J Am Acad Audiol 24:823–831 (2013)
Acceptable Noise Levels in Preschool Children with Normal Hearing DOI: 10.3766/jaaa.24.9.6 Melinda Freyaldenhoven Bryan* Clifford Franklin†‡ Krystal Sullivan Ware§ Rachel Horne**
Abstract Background: The acceptable noise level (ANL) measure is an indicator of hearing aid use. The majority of research in this area has focused primarily on adults. Research using school-aged listeners, specifically 8 and 12 yr old children, demonstrated that the average ANL values, standard deviations (SDs), and distribution of ANL values for these children were similar to those of adult listeners. Additionally, the ANL measure is reliable over time, even in school-aged listeners. Although ANL values from adult and school-aged listeners have been investigated, no research to date has been conducted using preschool children. Purpose: The purpose of the present study was to determine if ANLs could be obtained in preschool children, aged 4 and 5 yr, with normal hearing. This study also aimed to investigate the reliability and distribution of ANL measurements from preschool children, as well as any effect that background noise might present in the listening environment. Research Design: Seated in a sound-treated test suite, listeners were tasked with adjusting speech stimuli to their most comfortable listening level; then, with speech present, listeners were tasked with adjusting the background noise to their most acceptable background noise level. Three trials of each measure were averaged and were used to calculate each listener’s ANL. Study Sample: ANLs were attempted on 23 children, ages 4 yr (N 5 14) to 5 yr (N 5 9), with normal hearing. Results: Less than half of the 4 yr old listeners performed the ANL task, whereas all of the 5 yr old listeners completed the task successfully. Good test-retest reliability was found for those preschool children who were able to complete the task. Mean ANLs, SDs, ranges, and distributions demonstrated that these values agree with ANL data collected from older school-aged listeners. Conclusions: Although ANL values were reliably measured in all of the 5 yr old listeners, this was not the case for 4 yr old listeners. ANL values were not reliably obtained from 4 yr old listeners; however, the ANL procedure is appropriate for use for 5 yr old listeners. Furthermore, ANL means, SDs, ranges, and distributions were in agreement with those from older school-aged children and adults, and ANLs in preschool listeners were unaffected by the type of background noise stimuli. Key Words: Acceptance of noise, acceptable noise level, children, preschool children Abbreviations: ANL 5 acceptable noise level; ANOVA 5 analysis of variance; BNL 5 background noise level; MCL 5 most comfortable level; SBN 5 speech babble noise; SD 5 standard deviation; SSN 5 speech spectrum noise
*Louisiana Tech University, Ruston; †University of Arkansas at Little Rock; ‡University of Arkansas for Medical Sciences, Little Rock; §Overton Brooks VA Medical Center, Shreveport, LA; **Tampa Ear, Nose and Throat, FL Melinda F. Bryan, Associate Professor, Louisiana Tech University, PO Box 3165, Ruston, LA 71272; Phone: 318-257-2146; Fax: 318-257-4492; E-mail: [email protected] These data have been presented at the AudiologyNOW! 2009, Dallas, TX.
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INTRODUCTION
N
abelek et al (1991) introduced a procedure to measure the amount of background noise an individual is willing to listen to while following the words of a story. This procedure is known as acceptable noise level (ANL). To obtain an ANL, the listener adjusts running speech (e.g., Arizona Travelogue, Cosmos, Inc.) to his or her most comfortable listening level (MCL). Then, background noise (e.g., Revised SPIN, Cosmos, Inc.) is added and adjusted to a level that the listener is willing to “put up with” while listening to and following the words of a story. Originally, this procedure was used to measure how much background noise hearing aid users were willing to accept in order to investigate the relationship between hearing aid use and ANL (Nabelek et al, 1991). Results of the Nabelek et al (1991) study showed a direct relationship between hearing aid use and ANL in a small number of listeners. Nabelek et al (2006) continued the work of Nabelek et al (1991) by further investigating the (1) relationship between ANL and hearing aid use and (2) the predictability of hearing aid use on the basis of ANL score. Results revealed that ANLs were related to hearing aid use. Specifically, listeners with small ANLs accepted large amounts of background noise and were more likely to become full-time hearing aid users. Conversely, listeners with large ANLs accepted less background noise and were more likely to become part-time users or nonusers of hearing aids. Most importantly, the results showed that ANLs could predict hearing aid use with 85% accuracy. Furthermore, ANL research has also shown that ANLs are not related to age, gender, hearing sensitivity, and background noise stimuli with the exclusion of music, language, reported preference for background noise, pure-tone average, middle ear characteristics, or speech perception in noise performance (Freyaldenhoven and Smiley, 2006; Freyaldenhoven et al, 2006; Gordon-Hickey and Moore, 2008; Harkrider and Smith, 2005; Nabelek et al, 1991; Nabelek et al, 2006; Rogers et al, 2003; von Hapsburg and Bahng, 2006). It should be noted that most of the above discussed ANL research has been performed on the adult population. Therefore, to determine if ANLs could be measured in the pediatric population, Freyaldenhoven and Smiley (2006) measured ANLs in 32 children ages 8 and 12 yr. Results of this study demonstrated that ANLs could be reliably obtained in children ages 8 and 12 yr. Results further demonstrated that ANLs were not related to age, gender, or type of background noise stimuli, at least for children ages 8 and 12 yr. More importantly, the results showed that ANLs obtained in children were similar to the results obtained for the adult population. These results may indicate that ANLs in children may also be used to predict the success of hearing aid use in children with a hearing loss.
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Furthermore, Moore et al (2011) compared MCLs, background noise levels (BNLs), and ANLs in children (8–10 yr) and young adults (19–29 yr) with normal hearing. Results of the study revealed no significant difference in ANLs between children and adults; however, MCLs and BNLs were significantly higher for the adult population as compared to those obtained for children. These results indicated that ANLs are essentially unchanged from childhood to adulthood; however, differences in MCLs and BNLs were reported between the two groups (Moore et al, 2011). On the basis of available research, it would be reasonable to speculate that ANLs can be accurately measured in some children. However, at this point, what has not been determined is the youngest age that an ANL can be obtained in the pediatric population. With this knowledge, audiologists could understand at what age it would be practical to add ANL to the battery of tests used to document communication difficulties. Furthermore, ANLs are known to be a good predictor of hearing aid success in adult hearing aid users. It is unknown if this holds true for children with hearing loss; however, one of the first steps in answering this question is to determine the age at which ANLs can be accurately measured. Therefore, this study sought to determine if ANLs can be measured in preschoolaged children. The following research questions were addressed: 1. Can ANLs be reliably measured in preschool children ages 4 and 5 yr? 2. What are typical ANLs for preschool children ages 4 and 5 yr? 3. What is the distribution of ANLs in preschool children ages 4 and 5 yr? 4. Are ANLs affected by type of background noise in preschool children ages 4 and 5 yr?
METHODS Participants Data collection was attempted across two sites on 23 children with normal hearing. Seventeen of the children were tested on the Louisiana Tech University campus (Ruston, LA), and six of the children were tested on the Missouri State University campus (Springfield, MO). The specific inclusion criteria were as follows: (1) age 4 yr 0 mo to 5 yr 11 mo, and (2) normal hearing sensitivity (i.e., pass a pure-tone hearing screening at 20 dB HL for 0.5, 1, 2, and 4 kHz in each ear). Table 1 shows demographic information for the children across site and age. As you can see, ANLs were attempted on 14 children who were 4 yr 0 mo to 4 yr 11 mo (11 in Louisiana, 3 in Missouri), and ANLs were collected
ANLs in Preschool Children/Bryan et al
Table 1. Participant Demographic Information across Site and Age Site Louisiana (N 5 17) Age (yr) Race Gender
4 (N 5 11) Caucasian (N 5 11) Female (N 5 5) Male (N5 6)
Missouri (N 5 6)
5 (N 5 6) Caucasian (N 5 5) African American (N 5 1) Female (N 5 2) Male (N 5 4)
on 9 children who were 5 yr 0 mo to 5 yr 11 mo (6 in Louisiana, 3 in Missouri). Procedures The same test procedures were followed at both sites. Pure-tone hearing screenings were administered, and ANLs were measured in a sound-treated booth with acceptable ambient noise levels (ANSI S3; American National Standards Institute [ANSI], 1999). Speech and noise stimuli were delivered through a compact disk player (Tascam CD-160 – Louisiana; Sony SCDCE 545 – Missouri) routed through an audiometer (GSI-61 – Louisiana; Interacoustics AC40 – Missouri) to an ear-level loudspeaker located at 0° azimuth. A recording of male running speech (Arizona Travelogue, Cosmos Inc.) was used as the primary stimulus, and speech babble noise (SBN) (Revised SPIN, Cosmos Inc.) served as the competing stimuli. Furthermore, at the Louisiana site a secondary stimulus, speech spectrum noise (SSN) generated by the audiometer, was also used. All output levels for speech and noise stimuli were calibrated at the vertex of the listener and were checked periodically throughout the experiment. ANLs were measured using the procedures described by Freyaldenhoven and Smiley (2006). Before ANL testing began, the children were given two indicator buttons, which included the words and a pictorial representation of softer and louder. Each participant was instructed to use the indicator buttons to signal the examiner to manipulate the volume of the story and the background noise. The initial presentation for both the speech and background noises was 30 dB HL; both the MCL and BNLs were obtained using a method of adjustments. First, each participant was asked to adjust running speech to his or her MCL. Specifically, the children were instructed to increase the level of the story until “the level of the story was a little bit too loud.” Next, the children were asked to decrease the level of the speech until the story was just audible. These adjustments were completed using 5 dB steps. Lastly, the participants were asked to adjust the level of the story up and down to their MCL as if listening at their perfect listening level. This adjustment was completed using 2 dB steps. Then, background noise was introduced, and the participant was asked to adjust
4 (N 5 3) Caucasian (N 5 3)
5 (N 5 3) Caucasian (N 5 3)
Female (N 5 2) Male (N 5 1)
Female (N 5 2) Male (N 5 1)
the level of the background noise to the maximum he or she was willing to “put up with” while listening to and following the story (called BNL). Specifically, the participant adjusted the background noise up until the story could not be heard, and then down until the story was very clear. These adjustments were completed using 5 dB steps. Lastly, the children adjusted the level of the noise up or down to the maximum level of background noise that they were willing to accept or “put up with” without becoming tense or tired while listening to and following the words of the story. These adjustments were completed using 2 dB steps. Please note that during all testing, the participant was using the indicator buttons with the words “softer” and “louder” on them to signal the examiner to manipulate the volumes of the story and background noise; tapping the buttons was not directly changing the volume of the stimuli. The ANL was then calculated by subtracting the BNL from the MCL (i.e., MCL – BNL 5 ANL). Three ANL trials were obtained for each background noise (SSN [Louisiana Tech only] and SBN). It should be noted that ANLs obtained using SSN and SBN were counterbalanced at the Louisiana site. All experimental trials were completed within one session, lasting approximately 30 min. An average of the three trials for each background noise served as the mean ANL for that participant in the given condition. RESULTS Reliability One purpose of the present study was to determine if ANLs could be reliably obtained in preschool children with normal hearing. It should be noted that ANLs were attempted on 23 children ages 4–5 yr; however, eight children (34.8%) were excluded from the analysis because they did not complete the ANL task. Speech Babble Noise To determine the test-retest reliability of ANLs in children using SBN as the competing stimulus, single-measure intraclass correlation coefficients on the basis of the consistency definition were calculated for 15 (i.e., 23 – 8 5 15) children combined. It should be
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Figure 1. Scatterplots with lines of best fit comparing the three ANL trials for 15 children ages 4 and 5 yr using SBN as the background noise stimulus.
noted that, typically, for the behavioral sciences, intraclass correlation coefficients of $0.75 are interpreted as high (Boyle, 1991). The correlation coefficient for all children ages 4 and 5 yr (N 5 15) was r 5 0.80 (p , .001). Data for all children who completed the ANL task with SBN (N 5 15) are shown as scatterplots with accompanying R values for trial pairs (i.e., Trial 1–3, Trial 1–2, Trial 2–3) in Figure 1, and means and standard deviations (SDs) are listed in Table 2. Mean ANL results were analyzed using a two-factor repeatedmeasures analysis of variance (ANOVA). The withinparticipants factor was an ANL trial with three levels (Trial 1, 2, and 3), and the between-participants factor was age with two levels (ages 4 and 5 yr). No significant main effects were seen for ANL trial [F(2, 26) 5 2.26, p 5 .125], age [F(1, 13) 5 0.87, p 5 .368] or the ANL by age interaction [F(2, 26) 5 0.09, p 5 .911]. These results indicate no significant difference for ANLs obtained using SBN between the 3 trials, and ANLs did not significantly differ in listeners ages 4 and 5 yr old. Although no significant differences were noted in the above ANOVA, secondary data analyses revealed that many of the 4 yr old children either did not complete or did not finish the three ANL trails. This fact made the researchers question the reliability of ANL in 4 and 5 yr old children separately. Therefore, a secondary data analysis was completed to evaluate test-retest reliability for the 4 and 5 yr old children separately. For the 4 yr old children (N 5 14), the analysis showed that less than half of 4 yr old children (i.e., 42.9%) completed the ANL task. Of those who completed all three ANL trials,
the correlation coefficient was low (r 5 0.48, p 5 .04). Furthermore, data for the 4 yr old children who completed the ANL task with SBN (N 5 6) are shown as scatterplots with accompanying R values for trial pairs (i.e., Trial 1–3, Trial 1–2, Trial 2–3) in Figure 2, and means and SDs are listed in Table 2. Mean ANL results were analyzed using a one-way ANOVA. The withinparticipants factor was an ANL trial with three levels (Trial 1, 2, and 3). No significant main effects were seen for ANL trial [F(2, 10) 5 0.51, p 5 .61], indicating no significant difference for ANLs obtained with SBN between the three trials. Furthermore, all 5 yr old children completed the three ANL trials with high test-retest reliability (r 5 0.86, p , .001). ANL data for all 5 yr old children using SBN (N 5 9) are shown as scatterplots with accompanying R values for trial pairs (i.e., Trial 1–3, Trial 1–2, Trial 2–3) in Figure 3, and means and SDs are listed in Table 2. Mean ANL results were again analyzed using a one-way ANOVA. The within-participants factor was an ANL trial with three levels (Trial 1, 2, and 3). No significant main effects were seen for ANL trial [F(2, 16) 5 2.31, p 5 .13], indicating no significant difference for ANLs obtained with SBN between the 3 trials. Speech Spectrum Noise To determine the test-retest reliability of ANLs in children using SSN as the competing stimulus, another single-measure intraclass correlation coefficient on the basis of the consistency definition was calculated. It should be noted that ANLs using SSN were only completed in Louisiana (N 5 17). The correlation coefficient for all children ages 4 and 5 yr was r 5 0.79 ( p , .001). Data for all children who completed the ANL task with SSN (N 5 9) are shown as scatterplots with accompanying R values for trial pairs (i.e., Trial 1–3, Trial 1–2, Trial 2–3) in Figure 4, and means and SDs are listed in Table 3. Furthermore, mean ANLs were compared using a one-way ANOVA. The within-participants factor was ANL trial with three levels (Trial 1, 2, and 3). The between-participants factor of age was not analyzed because of the small number of participants in the 4 yr old group (N 5 3). No significant main effects were seen for ANL trial [F(2, 16) 5 0.29, p 5 .75], indicating that ANLs obtained with SSN between the three trials were similar.
Table 2. ANL Means and SDs (in dB) for All Children (N 5 15) Who Completed Three ANL Trials Reliably Using SBN as Background Noise Stimulus ANL (dB) All children (N 5 15) Age 4 yr (N 5 6) Age 5 yr (N 5 9)
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Trial 1
Trial 2
Trial 3
Mean
Mean Range
8.8 (6.4) 7.0 (5.2) 10.0 (7.1)
6.7 (5.7) 5.3 (4.2) 7.5 (6.6)
8.5 (5.8) 6.7 (2.8) 9.6 (7.1)
8.0 (5.5) 6.3 (3.4) 9.1 (6.6)
1.3–18.0 2.3–11.3 1.3–18.0
ANLs in Preschool Children/Bryan et al
Figure 2. Scatterplots with lines of best fit for the three ANL trials for six children age 4 yr using SBN as the background noise stimulus.
As previously stated, eight 4 yr old children (47.1%) were excluded from the analysis; for this reason, the test-retest reliability of ANLs was calculated for 4 and 5 yr old children separately. Similar to the results obtained using SBN, the results showed that only approximately one quarter (i.e., 27.3%) of 4 yr old children completed the ANL task. Stated differently, 72.7% of the 4 yr old children did not complete the ANL task. Because of the small number of participants, the correlational analysis was not completed for this group of children. Data for the 4 yr old children who completed the ANL task with SSN (N 5 3) are shown as scatterplots with accompanying R values for trial pairs (i.e., Trial 1–3, Trial 1–2, Trial 2–3) in Figure 5, and means and SDs are listed in Table 3. All 5 yr old children completed the three ANL trials with high test-retest reliability (r 5 0.75, p 5 .001). ANL data for all 5 yr old children using SBN (N 5 6) are shown as scatterplots with accompanying R-values for trial pairs (i.e., Trial 1–3, Trial 1–2, Trial 2–3) in
Figure 3. Scatterplots with lines of best fit for the three ANL trials for nine children age 5 yr using SBN as the background noise stimulus.
Figure 4. Scatterplots with lines of best fit for the three ANL trials for nine children ages 4 and 5 yr using SSN as the background noise stimulus.
Figure 6, and means and SDs are listed in Table 3. Mean ANL results were again analyzed using a one-way ANOVA. The within-participants factor was ANL trial with three levels (Trial 1, 2, and 3). No significant main effects were seen for ANL trial [F(2, 10) 5 0.20, p 5 .82], indicating no significant difference for ANLs obtained using SSN between the three trials. Typical ANL Values and Distributions The second purpose of the present study was to determine typical mean ANLs in preschool children ages 4–5 yr. ANLs were obtained three times for each noise type, and a mean ANL was determined for each participant with each type of background noise. Please note that the following sections will include data from all preschool children who completed the 3 ANL trials (N 5 15 for SBN and N 5 9 for SSN). Recall that Tables 2–3 show mean ANL data for SBN and SSN, respectively. As shown, mean ANLs for all children combined obtained using SBN and SSN are 8.0 and 6.1, respectively. These results indicate that mean ANLs and ranges for preschool children are similar to those of children and adults with normal hearing (Gordon-Hickey and Moore, 2008; Moore et al, 2011). The third purpose of the present study was to determine if ANLs in preschool children with normal hearing were normally distributed. A histogram was created for ANL measures for each background noise type (i.e., SBN and SSN, respectively; Figures 7A-B). Results of the distribution histograms for preschool children revealed that ANLs were near normal, centering z6– 8 dB for both types of background noise. Our final purpose was to determine if ANLs were affected by type of background noise for 4 and 5 yr old children. As such, a one-way ANOVA was completed with type of background noise as the independent variable and ANL as the dependent variable. The withinparticipants factor was type of background noise with
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Table 3. ANL Means and SDs (in dB) for All Children (N 5 9) Who Completed Three ANL Trials Using SSN as Background Noise Stimulus ANL (dB) All children (N 5 9) Age 4 yr (N 5 3) Age 5 yr (N 5 6)
Trial 1
Trial 2
Trial 3
Mean
Mean Range
6.8 (9.9) 8.0 (7.5) 6.2 (11.5)
5.8 (5.7) 8.0 (6.0) 4.7 (5.6)
5.7 (5.7) 6.3 (5.1) 5.3 (6.4)
6.1 (6.8) 7.4 (6.2) 5.3 (7.6)
22.3 to 19.0 1.7–14.0 22.3 to 19.0
two levels (SSN or SBN). The analysis revealed no significant main effects for type of background noise [F(1,8) 5 0.81, p 5 .40]. These results indicated that ANLs in preschool-aged children were not dependent on type of background noise. In summary, ANLs were only completed on approximately one quarter to one half of the 4 yr old children, depending on the background noise stimuli used. All 5 yr old children completed the ANL task with the testretest reliability being high. Furthermore, for those preschool children who completed all ANL trials, the mean, ranges, and distribution of ANL scores for these listeners were near normal. Lastly, ANLs were not related to type of background noise for these listeners.
he purposes of the present study were to determine the following: (1) the feasibility of obtaining reliable ANLs in preschool children with normal hearing; (2) typical mean ANLs for preschool children with normal hearing; (3) the distribution of ANLs in preschool children with normal hearing; and (4) the effect of type of background noise on ANL for these listeners. Recall that three ANL measurements were attempted for 23 preschool-aged children with normal hearing across two sites (Louisiana and Missouri), 14 children age 4 yr and 9 children age 5 yr. In addition, two types of background noise were used to evaluate ANL in a subset of children.
ANLs were reliably obtained in less than one half of the 4 yr old children with normal hearing. Furthermore, for those 4 yr old children who completed the ANL task, the test-retest reliability was low. However, ANLs were obtained in all 5 yr old children with high reliability. One explanation for these results is that most of the 4 yr old children tested, especially the children who did not complete the ANL task, were not yet in a structured school environment. On the other hand, all of the 5 yr old children participated in some sort of structured school environment, either preschool or kindergarten. On the basis of these results, the authors hypothesize that ANLs can be reliably obtained in children beginning at age 5 yr and/or after children enter a structured school setting. This is most likely because these children have had practice listening and following directions. Furthermore, this difference in the performance between 4 and 5 yr old listeners is consistent with expectations associated with the typical developmental milestones for language and cognitive abilities. For example, a normally developing child between ages 4 and 5 yr should be able to pay attention to a short story and possibly answer simple questions about the story (American Academy of Pediatrics, 2009; American Speech-Language-Hearing Association, n.d.). In addition to the developing language of children between 4 and 5 yr old, the ability to perform certain cognitive tasks in audiometric testing continues to develop during this period (Ross and Lerman, 1970; Jerger et al, 1980; Jerger et al, 1981; Jerger and Jerger, 1982; Jerger et al, 1983;
Figure 5. Scatterplots with lines of best fit for the three ANL trials for three children age 4 yr using SSN as the background noise stimulus. Please note that this analysis was completed using only three participants.
Figure 6. Scatterplots with lines of best fit for the three ANL trials for six children age 5 yr using SSN as the background noise stimulus.
DISCUSSION
T
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ANLs in Preschool Children/Bryan et al
Figure 7. Histogram displaying the frequency distribution of ANLs for preschool children ages 4.0–5.11 yr measured using SBN (N 5 15, 7A) and SSN (N 5 9, 7B).
Macpherson et al, 1991). The guidelines by the American Speech-Language-Hearing Association for hearing testing vary on techniques from infancy up to age 5 yr due to developmental limits (American Speech-LanguageHearing Association, 2004). At or around age 5 yr, the
guidelines recommend using the same testing techniques used with adults. Collectively, the ANL results (i.e., the correlational analysis, mean, SDs, and ranges) show that for listeners who completed all ANL trials, reliability is low for 4 yr old children and is high for 5 yr old children. Furthermore, the authors would like the readers to take note of the ANL values for Trials 1, 2, and 3 in Tables 2-3. As displayed for ANLs obtained on all children (N 5 15) using SBN, the means for Trials 1, 2, and 3 were 8.8, 6.7, and 8.5 dB, respectively. Although no significant difference among the trials was noted for speech spectrum or SBN, this trend in mean data (i.e., two of the ANL scores being very close in value whereby one of the scores is increased or decreased by 1–2 dB) was consistent. Analysis of individual data further displayed that 11 of the 15 participants (i.e., 73%) followed this trend. Due to this discovery and because the ANL can be obtained in z2 min, it is recommended that three ANLs be measured and the median score used when trying to determine the ANL for young listeners. Additionally, ANLs in the tested population were plotted on a distribution histogram for those listeners who completed the ANL procedure. The results of the distribution histogram (Figs. 7A-B) showed that ANLs were centered around 6–8 dB and ranged from 22.3 to 19 dB. These results are in good agreement with previous ANL research showing that ANLs typically center around 7–10 dB (Nabelek et al, 2006) and range from 21 to 24 dB (Gordon-Hickey and Moore, 2008; Nabelek et al, 1991; Rogers et al, 2003, Plyler et al, 2008). Table 4 shows a comparison of ANL means, SDs, and ranges for various ANL studies (Freyaldenhoven and Smiley, 2006; Gordon-Hickey and Moore, 2008; Moore et al, 2011; Plyler et al, 2008; Rogers et al, 2003). It should be noted that histograms from Freyaldenhoven and Smiley (2006) centered around 10 dB, whereas histograms from the present study centered around 6–8 dB, indicating that results from the present study revealed smaller ANLs. Furthermore, ANL means and ranges obtained in the present study are in agreement with other ANL studies for adults (Gordon-Hickey and Moore, 2008; Plyler et al, 2008) and children (Moore
Table 4. Comparison of Research Results for Mean ANLs (SDs) and Ranges (in dB) for Children and Adults with NH Mean ANL (SD) (in dB)
Range
Investigation
SBN ANL
SSN ANL
SBN ANL
SSN ANL
Present Study
N 5 15 8.0 (5.5) 9.7 (6.2) 8.4 (6.0) 7.1 (5.2) 7.82 (5.11) 10.9 (7.1)
N59 6.1 (6.8) 11.0 (5.7) NA NA NA NA
1.3–18.0 22.7 to 22.0 2–23.0 21 to 19.0 NA 0–24.7
22.3 to 19.0 22.7 to 21.7 NA NA NA NA
Freyaldenhoven and Smiley (2006) (N 5 32 children) Plyler et al (2008) (N 5 15 adults) Gordon-Hickey and Moore (2008) (N 5 30 adults) Moore et al (2011) (N 5 34 children) Rogers et al (2003) (N 5 50 adults) Note: NA 5 not available.
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et al, 2011) with normal hearing. Specifically, for the present study, mean ANLs ranged from 1.3–18 dB for SBN. Likewise, Rogers et al (2003) found ANLs to range from 0–24.7 dB, whereas von Hapsburg and Bahng (2006) measured a range from 22 to 20 dB, and Freyaldenhoven and Smiley (2006) measured ANLs ranging from 23 to 22 dB. ANLs were not dependent on type of background noise for these children. Specifically, the mean ANL for SBN was 8.0 dB, whereas the mean ANL for SSN was 6.1 dB; therefore, the mean difference between speech babble and SSNs was 1.9 dB. These results are consistent with those from Freyaldenhoven and Smiley (2006), who found mean ANLs of 9.7 dB for SBN and 11.0 dB for SSN (a difference of 1.3 dB). Furthermore, when comparing data from the present study to data from Freyaldenhoven and Smiley (2006), it should be noted that in the current study, ANLs were smaller when using SSN as compared to SBN. Conversely, Freyaldenhoven and Smiley (2006) found smaller ANLs when using SBN as the competing stimuli. This difference is perplexing and may be due to the difference in the age of the children. It should be noted, however, that in both studies ANLs between speech babble and spectrum noise were not significant, so although this difference existed and should be noted, the ANLs were not affected by background noise in either study. CONCLUSIONS AND CLINICAL IMPLICATIONS
T
he present study investigated typical ANL means and the reliability, distribution, and effect of type of background noise on ANL for preschool children ages 4 and 5 yr. ANLs were not reliably obtained in most 4 yr old children. The authors believe this was because these children could not be conditioned to the task because they could not understand the instructions given. As such, it is not recommended as a clinical tool for audiologists in listeners this young. However, 5 yr old children could complete the ANL task with high reliability within a session. For this reason, ANL may be added to the battery of tests used by audiologists for listeners beginning at age 5 yr or upon entry into a structured school setting. However, please note that when obtaining ANLs in young listeners, we recommend that ANLs be obtained three times, and the median score used as the listener’s ANL. The addition of ANL as a clinical tool for pediatric audiologists is important because children are typically poor reporters regarding factors related to hearing and/ or amplification (Kawell et al, 1988; Macpherson et al, 1991). Therefore, this research should be extended to children who use amplification to determine (1) if ANL is a predictor of hearing aid use, and (2) to potentially document or validate necessary hearing aid features for young listeners to effectively communicate.
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The results also showed that mean ANLs were similar to ANLs obtained from older children (i.e., 8–12 yr) and adults with normal hearing sensitivity. ANLs were also normally distributed for these children. These results indicate that ANLs measured in the preschool children with normal hearing are much like ANLs obtained in older children with normal hearing and adults with normal and impaired hearing. Lastly, the results revealed no difference between ANLs measured using speech babble and SSN. These results indicate that audiologists who do not have access to the traditional ANL stimuli can use running speech and background noise generated from the audiometer with no effect of ANLs, even for preschool-aged children. REFERENCES American Academy of Pediatrics. (2009) Caring for Your Baby and Young Child: Birth to age 5. USA: Bantam Books. American National Standards Institute. (1999) Maximum Permissible Ambient Noise Levels for Audiometric Test Rooms. (ANSI S3. 1-1999). New York: American National Standards Institute. American Speech-Language-Hearing Association. (n.d.) Development: Four to Five Years. Retrieved from http://www.asha.org/ public/speech/development/45.htm. American Speech-Language-Hearing Association. (2004) Guidelines for the Audiologic Assessment of Children From Birth to 5 Years of Age. Rockville, MD: Author. Boyle GJ. (1991) Does item homogeneity indicate internal consistency or item redundancy in psychometric scales? Pers Individ Dif 12:291–294. Freyaldenhoven MC, Smiley DF. (2006) Acceptance of background noise in children with normal hearing. J Ed Audiol 13:27–31. Freyaldenhoven MC, Smiley DF, Muenchen R, Konrad T. (2006) Acceptable noise level: reliability measures and comparison to preference for background sounds. J Am Acad Audiol 17:640–648. Gordon-Hickey S, Moore R. (2008) Acceptance of noise with intelligible, reversed, and unfamiliar primary discourse. Am J Audiol 17: 129–135. Harkrider AW, Smith SB. (2005) Acceptable noise level, phoneme recognition in noise, and measures of auditory efferent activity. J Am Acad Audiol 16:530–545. Jerger S, Lewis S, Hawkins J, Jerger J. (1980) Pediatric speech intelligibility test. I. Generation of test materials. Int J Pediatr Otorhinolaryngol 2:217–230. Jerger S, Jerger J, Lewis S. (1981) Pediatric speech intelligibility test. II. Effect of receptive language age and chronological age. Int J Pediatr Otorhinolaryngol 3:101–118. Jerger S, Jerger J. (1982) Pediatric speech intelligibility test: performance-intensity characteristics. Ear Hear 3:325–334. Jerger S, Jerger J, Abrams S. (1983) Speech audiometry in the young child. Ear Hear 4:56–66. Kawell ME, Kopun JG, Stelmachowicz PG. (1988) Loudness discomfort levels in children. Ear Hear 9:133–136.
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Macpherson BJ, Elfenbein JL, Schum RL, Bentler RA. (1991) Thresholds of discomfort in young children. Ear Hear 12:184–190. Moore R, Gordan-Hickey S, Jones A. (2011) Most comfortable listening levels, background noise levels, and acceptable noise levels for children and adults with normal hearing. J Am Acad Audiol 22:286–293.
Plyler PN, Bahng J, von Hapsburg D. (2008) The acceptance of background noise in adult cochlear implant users. J Speech Hear Lang Res 51:502–515. Rogers DS, Harkrider AW, Burchfield SB, Nabelek AK. (2003) The influence of listener’s gender on the acceptance of background noise. J Am Acad Audiol 14:372–382.
Nabelek AK, Freyaldenhoven MC, Tampas JW, Burchfield SB, Muenchen RA. (2006) Acceptable noise level as a predictor of hearing aid use. J Am Acad Audiol 17:626–639.
Ross M, Lerman J. (1970) A picture identification test for hearingimpaired children. J Speech Hear Res 13:44–53.
Nabelek AK, Tucker FM, Letowski TR. (1991) Toleration of background noises: relationship with patterns of hearing aid use by elderly persons. J Speech Hear Res 34:679–685.
von Hapsburg D, Bahng J. (2006) Acceptance of background noise levels in bilingual [Korean-English] listeners. J Am Acad Audiol 17:649–658.
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Acceptable Noise Levels in Preschool Children with Normal Hearing DOI: 10.3766/jaaa.24.9.6 Melinda Freyaldenhoven Bryan* Clifford Franklin†‡ Krystal Sullivan Ware§ Rachel Horne**
Abstract Background: The acceptable noise level (ANL) measure is an indicator of hearing aid use. The majority of research in this area has focused primarily on adults. Research using school-aged listeners, specifically 8 and 12 yr old children, demonstrated that the average ANL values, standard deviations (SDs), and distribution of ANL values for these children were similar to those of adult listeners. Additionally, the ANL measure is reliable over time, even in school-aged listeners. Although ANL values from adult and school-aged listeners have been investigated, no research to date has been conducted using preschool children. Purpose: The purpose of the present study was to determine if ANLs could be obtained in preschool children, aged 4 and 5 yr, with normal hearing. This study also aimed to investigate the reliability and distribution of ANL measurements from preschool children, as well as any effect that background noise might present in the listening environment. Research Design: Seated in a sound-treated test suite, listeners were tasked with adjusting speech stimuli to their most comfortable listening level; then, with speech present, listeners were tasked with adjusting the background noise to their most acceptable background noise level. Three trials of each measure were averaged and were used to calculate each listener’s ANL. Study Sample: ANLs were attempted on 23 children, ages 4 yr (N 5 14) to 5 yr (N 5 9), with normal hearing. Results: Less than half of the 4 yr old listeners performed the ANL task, whereas all of the 5 yr old listeners completed the task successfully. Good test-retest reliability was found for those preschool children who were able to complete the task. Mean ANLs, SDs, ranges, and distributions demonstrated that these values agree with ANL data collected from older school-aged listeners. Conclusions: Although ANL values were reliably measured in all of the 5 yr old listeners, this was not the case for 4 yr old listeners. ANL values were not reliably obtained from 4 yr old listeners; however, the ANL procedure is appropriate for use for 5 yr old listeners. Furthermore, ANL means, SDs, ranges, and distributions were in agreement with those from older school-aged children and adults, and ANLs in preschool listeners were unaffected by the type of background noise stimuli. Key Words: Acceptance of noise, acceptable noise level, children, preschool children Abbreviations: ANL 5 acceptable noise level; ANOVA 5 analysis of variance; BNL 5 background noise level; MCL 5 most comfortable level; SBN 5 speech babble noise; SD 5 standard deviation; SSN 5 speech spectrum noise
*Louisiana Tech University, Ruston; †University of Arkansas at Little Rock; ‡University of Arkansas for Medical Sciences, Little Rock; §Overton Brooks VA Medical Center, Shreveport, LA; **Tampa Ear, Nose and Throat, FL Melinda F. Bryan, Associate Professor, Louisiana Tech University, PO Box 3165, Ruston, LA 71272; Phone: 318-257-2146; Fax: 318-257-4492; E-mail: [email protected] These data have been presented at the AudiologyNOW! 2009, Dallas, TX.
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INTRODUCTION
N
abelek et al (1991) introduced a procedure to measure the amount of background noise an individual is willing to listen to while following the words of a story. This procedure is known as acceptable noise level (ANL). To obtain an ANL, the listener adjusts running speech (e.g., Arizona Travelogue, Cosmos, Inc.) to his or her most comfortable listening level (MCL). Then, background noise (e.g., Revised SPIN, Cosmos, Inc.) is added and adjusted to a level that the listener is willing to “put up with” while listening to and following the words of a story. Originally, this procedure was used to measure how much background noise hearing aid users were willing to accept in order to investigate the relationship between hearing aid use and ANL (Nabelek et al, 1991). Results of the Nabelek et al (1991) study showed a direct relationship between hearing aid use and ANL in a small number of listeners. Nabelek et al (2006) continued the work of Nabelek et al (1991) by further investigating the (1) relationship between ANL and hearing aid use and (2) the predictability of hearing aid use on the basis of ANL score. Results revealed that ANLs were related to hearing aid use. Specifically, listeners with small ANLs accepted large amounts of background noise and were more likely to become full-time hearing aid users. Conversely, listeners with large ANLs accepted less background noise and were more likely to become part-time users or nonusers of hearing aids. Most importantly, the results showed that ANLs could predict hearing aid use with 85% accuracy. Furthermore, ANL research has also shown that ANLs are not related to age, gender, hearing sensitivity, and background noise stimuli with the exclusion of music, language, reported preference for background noise, pure-tone average, middle ear characteristics, or speech perception in noise performance (Freyaldenhoven and Smiley, 2006; Freyaldenhoven et al, 2006; Gordon-Hickey and Moore, 2008; Harkrider and Smith, 2005; Nabelek et al, 1991; Nabelek et al, 2006; Rogers et al, 2003; von Hapsburg and Bahng, 2006). It should be noted that most of the above discussed ANL research has been performed on the adult population. Therefore, to determine if ANLs could be measured in the pediatric population, Freyaldenhoven and Smiley (2006) measured ANLs in 32 children ages 8 and 12 yr. Results of this study demonstrated that ANLs could be reliably obtained in children ages 8 and 12 yr. Results further demonstrated that ANLs were not related to age, gender, or type of background noise stimuli, at least for children ages 8 and 12 yr. More importantly, the results showed that ANLs obtained in children were similar to the results obtained for the adult population. These results may indicate that ANLs in children may also be used to predict the success of hearing aid use in children with a hearing loss.
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Furthermore, Moore et al (2011) compared MCLs, background noise levels (BNLs), and ANLs in children (8–10 yr) and young adults (19–29 yr) with normal hearing. Results of the study revealed no significant difference in ANLs between children and adults; however, MCLs and BNLs were significantly higher for the adult population as compared to those obtained for children. These results indicated that ANLs are essentially unchanged from childhood to adulthood; however, differences in MCLs and BNLs were reported between the two groups (Moore et al, 2011). On the basis of available research, it would be reasonable to speculate that ANLs can be accurately measured in some children. However, at this point, what has not been determined is the youngest age that an ANL can be obtained in the pediatric population. With this knowledge, audiologists could understand at what age it would be practical to add ANL to the battery of tests used to document communication difficulties. Furthermore, ANLs are known to be a good predictor of hearing aid success in adult hearing aid users. It is unknown if this holds true for children with hearing loss; however, one of the first steps in answering this question is to determine the age at which ANLs can be accurately measured. Therefore, this study sought to determine if ANLs can be measured in preschoolaged children. The following research questions were addressed: 1. Can ANLs be reliably measured in preschool children ages 4 and 5 yr? 2. What are typical ANLs for preschool children ages 4 and 5 yr? 3. What is the distribution of ANLs in preschool children ages 4 and 5 yr? 4. Are ANLs affected by type of background noise in preschool children ages 4 and 5 yr?
METHODS Participants Data collection was attempted across two sites on 23 children with normal hearing. Seventeen of the children were tested on the Louisiana Tech University campus (Ruston, LA), and six of the children were tested on the Missouri State University campus (Springfield, MO). The specific inclusion criteria were as follows: (1) age 4 yr 0 mo to 5 yr 11 mo, and (2) normal hearing sensitivity (i.e., pass a pure-tone hearing screening at 20 dB HL for 0.5, 1, 2, and 4 kHz in each ear). Table 1 shows demographic information for the children across site and age. As you can see, ANLs were attempted on 14 children who were 4 yr 0 mo to 4 yr 11 mo (11 in Louisiana, 3 in Missouri), and ANLs were collected
ANLs in Preschool Children/Bryan et al
Table 1. Participant Demographic Information across Site and Age Site Louisiana (N 5 17) Age (yr) Race Gender
4 (N 5 11) Caucasian (N 5 11) Female (N 5 5) Male (N5 6)
Missouri (N 5 6)
5 (N 5 6) Caucasian (N 5 5) African American (N 5 1) Female (N 5 2) Male (N 5 4)
on 9 children who were 5 yr 0 mo to 5 yr 11 mo (6 in Louisiana, 3 in Missouri). Procedures The same test procedures were followed at both sites. Pure-tone hearing screenings were administered, and ANLs were measured in a sound-treated booth with acceptable ambient noise levels (ANSI S3; American National Standards Institute [ANSI], 1999). Speech and noise stimuli were delivered through a compact disk player (Tascam CD-160 – Louisiana; Sony SCDCE 545 – Missouri) routed through an audiometer (GSI-61 – Louisiana; Interacoustics AC40 – Missouri) to an ear-level loudspeaker located at 0° azimuth. A recording of male running speech (Arizona Travelogue, Cosmos Inc.) was used as the primary stimulus, and speech babble noise (SBN) (Revised SPIN, Cosmos Inc.) served as the competing stimuli. Furthermore, at the Louisiana site a secondary stimulus, speech spectrum noise (SSN) generated by the audiometer, was also used. All output levels for speech and noise stimuli were calibrated at the vertex of the listener and were checked periodically throughout the experiment. ANLs were measured using the procedures described by Freyaldenhoven and Smiley (2006). Before ANL testing began, the children were given two indicator buttons, which included the words and a pictorial representation of softer and louder. Each participant was instructed to use the indicator buttons to signal the examiner to manipulate the volume of the story and the background noise. The initial presentation for both the speech and background noises was 30 dB HL; both the MCL and BNLs were obtained using a method of adjustments. First, each participant was asked to adjust running speech to his or her MCL. Specifically, the children were instructed to increase the level of the story until “the level of the story was a little bit too loud.” Next, the children were asked to decrease the level of the speech until the story was just audible. These adjustments were completed using 5 dB steps. Lastly, the participants were asked to adjust the level of the story up and down to their MCL as if listening at their perfect listening level. This adjustment was completed using 2 dB steps. Then, background noise was introduced, and the participant was asked to adjust
4 (N 5 3) Caucasian (N 5 3)
5 (N 5 3) Caucasian (N 5 3)
Female (N 5 2) Male (N 5 1)
Female (N 5 2) Male (N 5 1)
the level of the background noise to the maximum he or she was willing to “put up with” while listening to and following the story (called BNL). Specifically, the participant adjusted the background noise up until the story could not be heard, and then down until the story was very clear. These adjustments were completed using 5 dB steps. Lastly, the children adjusted the level of the noise up or down to the maximum level of background noise that they were willing to accept or “put up with” without becoming tense or tired while listening to and following the words of the story. These adjustments were completed using 2 dB steps. Please note that during all testing, the participant was using the indicator buttons with the words “softer” and “louder” on them to signal the examiner to manipulate the volumes of the story and background noise; tapping the buttons was not directly changing the volume of the stimuli. The ANL was then calculated by subtracting the BNL from the MCL (i.e., MCL – BNL 5 ANL). Three ANL trials were obtained for each background noise (SSN [Louisiana Tech only] and SBN). It should be noted that ANLs obtained using SSN and SBN were counterbalanced at the Louisiana site. All experimental trials were completed within one session, lasting approximately 30 min. An average of the three trials for each background noise served as the mean ANL for that participant in the given condition. RESULTS Reliability One purpose of the present study was to determine if ANLs could be reliably obtained in preschool children with normal hearing. It should be noted that ANLs were attempted on 23 children ages 4–5 yr; however, eight children (34.8%) were excluded from the analysis because they did not complete the ANL task. Speech Babble Noise To determine the test-retest reliability of ANLs in children using SBN as the competing stimulus, single-measure intraclass correlation coefficients on the basis of the consistency definition were calculated for 15 (i.e., 23 – 8 5 15) children combined. It should be
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Figure 1. Scatterplots with lines of best fit comparing the three ANL trials for 15 children ages 4 and 5 yr using SBN as the background noise stimulus.
noted that, typically, for the behavioral sciences, intraclass correlation coefficients of $0.75 are interpreted as high (Boyle, 1991). The correlation coefficient for all children ages 4 and 5 yr (N 5 15) was r 5 0.80 (p , .001). Data for all children who completed the ANL task with SBN (N 5 15) are shown as scatterplots with accompanying R values for trial pairs (i.e., Trial 1–3, Trial 1–2, Trial 2–3) in Figure 1, and means and standard deviations (SDs) are listed in Table 2. Mean ANL results were analyzed using a two-factor repeatedmeasures analysis of variance (ANOVA). The withinparticipants factor was an ANL trial with three levels (Trial 1, 2, and 3), and the between-participants factor was age with two levels (ages 4 and 5 yr). No significant main effects were seen for ANL trial [F(2, 26) 5 2.26, p 5 .125], age [F(1, 13) 5 0.87, p 5 .368] or the ANL by age interaction [F(2, 26) 5 0.09, p 5 .911]. These results indicate no significant difference for ANLs obtained using SBN between the 3 trials, and ANLs did not significantly differ in listeners ages 4 and 5 yr old. Although no significant differences were noted in the above ANOVA, secondary data analyses revealed that many of the 4 yr old children either did not complete or did not finish the three ANL trails. This fact made the researchers question the reliability of ANL in 4 and 5 yr old children separately. Therefore, a secondary data analysis was completed to evaluate test-retest reliability for the 4 and 5 yr old children separately. For the 4 yr old children (N 5 14), the analysis showed that less than half of 4 yr old children (i.e., 42.9%) completed the ANL task. Of those who completed all three ANL trials,
the correlation coefficient was low (r 5 0.48, p 5 .04). Furthermore, data for the 4 yr old children who completed the ANL task with SBN (N 5 6) are shown as scatterplots with accompanying R values for trial pairs (i.e., Trial 1–3, Trial 1–2, Trial 2–3) in Figure 2, and means and SDs are listed in Table 2. Mean ANL results were analyzed using a one-way ANOVA. The withinparticipants factor was an ANL trial with three levels (Trial 1, 2, and 3). No significant main effects were seen for ANL trial [F(2, 10) 5 0.51, p 5 .61], indicating no significant difference for ANLs obtained with SBN between the three trials. Furthermore, all 5 yr old children completed the three ANL trials with high test-retest reliability (r 5 0.86, p , .001). ANL data for all 5 yr old children using SBN (N 5 9) are shown as scatterplots with accompanying R values for trial pairs (i.e., Trial 1–3, Trial 1–2, Trial 2–3) in Figure 3, and means and SDs are listed in Table 2. Mean ANL results were again analyzed using a one-way ANOVA. The within-participants factor was an ANL trial with three levels (Trial 1, 2, and 3). No significant main effects were seen for ANL trial [F(2, 16) 5 2.31, p 5 .13], indicating no significant difference for ANLs obtained with SBN between the 3 trials. Speech Spectrum Noise To determine the test-retest reliability of ANLs in children using SSN as the competing stimulus, another single-measure intraclass correlation coefficient on the basis of the consistency definition was calculated. It should be noted that ANLs using SSN were only completed in Louisiana (N 5 17). The correlation coefficient for all children ages 4 and 5 yr was r 5 0.79 ( p , .001). Data for all children who completed the ANL task with SSN (N 5 9) are shown as scatterplots with accompanying R values for trial pairs (i.e., Trial 1–3, Trial 1–2, Trial 2–3) in Figure 4, and means and SDs are listed in Table 3. Furthermore, mean ANLs were compared using a one-way ANOVA. The within-participants factor was ANL trial with three levels (Trial 1, 2, and 3). The between-participants factor of age was not analyzed because of the small number of participants in the 4 yr old group (N 5 3). No significant main effects were seen for ANL trial [F(2, 16) 5 0.29, p 5 .75], indicating that ANLs obtained with SSN between the three trials were similar.
Table 2. ANL Means and SDs (in dB) for All Children (N 5 15) Who Completed Three ANL Trials Reliably Using SBN as Background Noise Stimulus ANL (dB) All children (N 5 15) Age 4 yr (N 5 6) Age 5 yr (N 5 9)
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Trial 1
Trial 2
Trial 3
Mean
Mean Range
8.8 (6.4) 7.0 (5.2) 10.0 (7.1)
6.7 (5.7) 5.3 (4.2) 7.5 (6.6)
8.5 (5.8) 6.7 (2.8) 9.6 (7.1)
8.0 (5.5) 6.3 (3.4) 9.1 (6.6)
1.3–18.0 2.3–11.3 1.3–18.0
ANLs in Preschool Children/Bryan et al
Figure 2. Scatterplots with lines of best fit for the three ANL trials for six children age 4 yr using SBN as the background noise stimulus.
As previously stated, eight 4 yr old children (47.1%) were excluded from the analysis; for this reason, the test-retest reliability of ANLs was calculated for 4 and 5 yr old children separately. Similar to the results obtained using SBN, the results showed that only approximately one quarter (i.e., 27.3%) of 4 yr old children completed the ANL task. Stated differently, 72.7% of the 4 yr old children did not complete the ANL task. Because of the small number of participants, the correlational analysis was not completed for this group of children. Data for the 4 yr old children who completed the ANL task with SSN (N 5 3) are shown as scatterplots with accompanying R values for trial pairs (i.e., Trial 1–3, Trial 1–2, Trial 2–3) in Figure 5, and means and SDs are listed in Table 3. All 5 yr old children completed the three ANL trials with high test-retest reliability (r 5 0.75, p 5 .001). ANL data for all 5 yr old children using SBN (N 5 6) are shown as scatterplots with accompanying R-values for trial pairs (i.e., Trial 1–3, Trial 1–2, Trial 2–3) in
Figure 3. Scatterplots with lines of best fit for the three ANL trials for nine children age 5 yr using SBN as the background noise stimulus.
Figure 4. Scatterplots with lines of best fit for the three ANL trials for nine children ages 4 and 5 yr using SSN as the background noise stimulus.
Figure 6, and means and SDs are listed in Table 3. Mean ANL results were again analyzed using a one-way ANOVA. The within-participants factor was ANL trial with three levels (Trial 1, 2, and 3). No significant main effects were seen for ANL trial [F(2, 10) 5 0.20, p 5 .82], indicating no significant difference for ANLs obtained using SSN between the three trials. Typical ANL Values and Distributions The second purpose of the present study was to determine typical mean ANLs in preschool children ages 4–5 yr. ANLs were obtained three times for each noise type, and a mean ANL was determined for each participant with each type of background noise. Please note that the following sections will include data from all preschool children who completed the 3 ANL trials (N 5 15 for SBN and N 5 9 for SSN). Recall that Tables 2–3 show mean ANL data for SBN and SSN, respectively. As shown, mean ANLs for all children combined obtained using SBN and SSN are 8.0 and 6.1, respectively. These results indicate that mean ANLs and ranges for preschool children are similar to those of children and adults with normal hearing (Gordon-Hickey and Moore, 2008; Moore et al, 2011). The third purpose of the present study was to determine if ANLs in preschool children with normal hearing were normally distributed. A histogram was created for ANL measures for each background noise type (i.e., SBN and SSN, respectively; Figures 7A-B). Results of the distribution histograms for preschool children revealed that ANLs were near normal, centering z6– 8 dB for both types of background noise. Our final purpose was to determine if ANLs were affected by type of background noise for 4 and 5 yr old children. As such, a one-way ANOVA was completed with type of background noise as the independent variable and ANL as the dependent variable. The withinparticipants factor was type of background noise with
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Table 3. ANL Means and SDs (in dB) for All Children (N 5 9) Who Completed Three ANL Trials Using SSN as Background Noise Stimulus ANL (dB) All children (N 5 9) Age 4 yr (N 5 3) Age 5 yr (N 5 6)
Trial 1
Trial 2
Trial 3
Mean
Mean Range
6.8 (9.9) 8.0 (7.5) 6.2 (11.5)
5.8 (5.7) 8.0 (6.0) 4.7 (5.6)
5.7 (5.7) 6.3 (5.1) 5.3 (6.4)
6.1 (6.8) 7.4 (6.2) 5.3 (7.6)
22.3 to 19.0 1.7–14.0 22.3 to 19.0
two levels (SSN or SBN). The analysis revealed no significant main effects for type of background noise [F(1,8) 5 0.81, p 5 .40]. These results indicated that ANLs in preschool-aged children were not dependent on type of background noise. In summary, ANLs were only completed on approximately one quarter to one half of the 4 yr old children, depending on the background noise stimuli used. All 5 yr old children completed the ANL task with the testretest reliability being high. Furthermore, for those preschool children who completed all ANL trials, the mean, ranges, and distribution of ANL scores for these listeners were near normal. Lastly, ANLs were not related to type of background noise for these listeners.
he purposes of the present study were to determine the following: (1) the feasibility of obtaining reliable ANLs in preschool children with normal hearing; (2) typical mean ANLs for preschool children with normal hearing; (3) the distribution of ANLs in preschool children with normal hearing; and (4) the effect of type of background noise on ANL for these listeners. Recall that three ANL measurements were attempted for 23 preschool-aged children with normal hearing across two sites (Louisiana and Missouri), 14 children age 4 yr and 9 children age 5 yr. In addition, two types of background noise were used to evaluate ANL in a subset of children.
ANLs were reliably obtained in less than one half of the 4 yr old children with normal hearing. Furthermore, for those 4 yr old children who completed the ANL task, the test-retest reliability was low. However, ANLs were obtained in all 5 yr old children with high reliability. One explanation for these results is that most of the 4 yr old children tested, especially the children who did not complete the ANL task, were not yet in a structured school environment. On the other hand, all of the 5 yr old children participated in some sort of structured school environment, either preschool or kindergarten. On the basis of these results, the authors hypothesize that ANLs can be reliably obtained in children beginning at age 5 yr and/or after children enter a structured school setting. This is most likely because these children have had practice listening and following directions. Furthermore, this difference in the performance between 4 and 5 yr old listeners is consistent with expectations associated with the typical developmental milestones for language and cognitive abilities. For example, a normally developing child between ages 4 and 5 yr should be able to pay attention to a short story and possibly answer simple questions about the story (American Academy of Pediatrics, 2009; American Speech-Language-Hearing Association, n.d.). In addition to the developing language of children between 4 and 5 yr old, the ability to perform certain cognitive tasks in audiometric testing continues to develop during this period (Ross and Lerman, 1970; Jerger et al, 1980; Jerger et al, 1981; Jerger and Jerger, 1982; Jerger et al, 1983;
Figure 5. Scatterplots with lines of best fit for the three ANL trials for three children age 4 yr using SSN as the background noise stimulus. Please note that this analysis was completed using only three participants.
Figure 6. Scatterplots with lines of best fit for the three ANL trials for six children age 5 yr using SSN as the background noise stimulus.
DISCUSSION
T
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Figure 7. Histogram displaying the frequency distribution of ANLs for preschool children ages 4.0–5.11 yr measured using SBN (N 5 15, 7A) and SSN (N 5 9, 7B).
Macpherson et al, 1991). The guidelines by the American Speech-Language-Hearing Association for hearing testing vary on techniques from infancy up to age 5 yr due to developmental limits (American Speech-LanguageHearing Association, 2004). At or around age 5 yr, the
guidelines recommend using the same testing techniques used with adults. Collectively, the ANL results (i.e., the correlational analysis, mean, SDs, and ranges) show that for listeners who completed all ANL trials, reliability is low for 4 yr old children and is high for 5 yr old children. Furthermore, the authors would like the readers to take note of the ANL values for Trials 1, 2, and 3 in Tables 2-3. As displayed for ANLs obtained on all children (N 5 15) using SBN, the means for Trials 1, 2, and 3 were 8.8, 6.7, and 8.5 dB, respectively. Although no significant difference among the trials was noted for speech spectrum or SBN, this trend in mean data (i.e., two of the ANL scores being very close in value whereby one of the scores is increased or decreased by 1–2 dB) was consistent. Analysis of individual data further displayed that 11 of the 15 participants (i.e., 73%) followed this trend. Due to this discovery and because the ANL can be obtained in z2 min, it is recommended that three ANLs be measured and the median score used when trying to determine the ANL for young listeners. Additionally, ANLs in the tested population were plotted on a distribution histogram for those listeners who completed the ANL procedure. The results of the distribution histogram (Figs. 7A-B) showed that ANLs were centered around 6–8 dB and ranged from 22.3 to 19 dB. These results are in good agreement with previous ANL research showing that ANLs typically center around 7–10 dB (Nabelek et al, 2006) and range from 21 to 24 dB (Gordon-Hickey and Moore, 2008; Nabelek et al, 1991; Rogers et al, 2003, Plyler et al, 2008). Table 4 shows a comparison of ANL means, SDs, and ranges for various ANL studies (Freyaldenhoven and Smiley, 2006; Gordon-Hickey and Moore, 2008; Moore et al, 2011; Plyler et al, 2008; Rogers et al, 2003). It should be noted that histograms from Freyaldenhoven and Smiley (2006) centered around 10 dB, whereas histograms from the present study centered around 6–8 dB, indicating that results from the present study revealed smaller ANLs. Furthermore, ANL means and ranges obtained in the present study are in agreement with other ANL studies for adults (Gordon-Hickey and Moore, 2008; Plyler et al, 2008) and children (Moore
Table 4. Comparison of Research Results for Mean ANLs (SDs) and Ranges (in dB) for Children and Adults with NH Mean ANL (SD) (in dB)
Range
Investigation
SBN ANL
SSN ANL
SBN ANL
SSN ANL
Present Study
N 5 15 8.0 (5.5) 9.7 (6.2) 8.4 (6.0) 7.1 (5.2) 7.82 (5.11) 10.9 (7.1)
N59 6.1 (6.8) 11.0 (5.7) NA NA NA NA
1.3–18.0 22.7 to 22.0 2–23.0 21 to 19.0 NA 0–24.7
22.3 to 19.0 22.7 to 21.7 NA NA NA NA
Freyaldenhoven and Smiley (2006) (N 5 32 children) Plyler et al (2008) (N 5 15 adults) Gordon-Hickey and Moore (2008) (N 5 30 adults) Moore et al (2011) (N 5 34 children) Rogers et al (2003) (N 5 50 adults) Note: NA 5 not available.
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et al, 2011) with normal hearing. Specifically, for the present study, mean ANLs ranged from 1.3–18 dB for SBN. Likewise, Rogers et al (2003) found ANLs to range from 0–24.7 dB, whereas von Hapsburg and Bahng (2006) measured a range from 22 to 20 dB, and Freyaldenhoven and Smiley (2006) measured ANLs ranging from 23 to 22 dB. ANLs were not dependent on type of background noise for these children. Specifically, the mean ANL for SBN was 8.0 dB, whereas the mean ANL for SSN was 6.1 dB; therefore, the mean difference between speech babble and SSNs was 1.9 dB. These results are consistent with those from Freyaldenhoven and Smiley (2006), who found mean ANLs of 9.7 dB for SBN and 11.0 dB for SSN (a difference of 1.3 dB). Furthermore, when comparing data from the present study to data from Freyaldenhoven and Smiley (2006), it should be noted that in the current study, ANLs were smaller when using SSN as compared to SBN. Conversely, Freyaldenhoven and Smiley (2006) found smaller ANLs when using SBN as the competing stimuli. This difference is perplexing and may be due to the difference in the age of the children. It should be noted, however, that in both studies ANLs between speech babble and spectrum noise were not significant, so although this difference existed and should be noted, the ANLs were not affected by background noise in either study. CONCLUSIONS AND CLINICAL IMPLICATIONS
T
he present study investigated typical ANL means and the reliability, distribution, and effect of type of background noise on ANL for preschool children ages 4 and 5 yr. ANLs were not reliably obtained in most 4 yr old children. The authors believe this was because these children could not be conditioned to the task because they could not understand the instructions given. As such, it is not recommended as a clinical tool for audiologists in listeners this young. However, 5 yr old children could complete the ANL task with high reliability within a session. For this reason, ANL may be added to the battery of tests used by audiologists for listeners beginning at age 5 yr or upon entry into a structured school setting. However, please note that when obtaining ANLs in young listeners, we recommend that ANLs be obtained three times, and the median score used as the listener’s ANL. The addition of ANL as a clinical tool for pediatric audiologists is important because children are typically poor reporters regarding factors related to hearing and/ or amplification (Kawell et al, 1988; Macpherson et al, 1991). Therefore, this research should be extended to children who use amplification to determine (1) if ANL is a predictor of hearing aid use, and (2) to potentially document or validate necessary hearing aid features for young listeners to effectively communicate.
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The results also showed that mean ANLs were similar to ANLs obtained from older children (i.e., 8–12 yr) and adults with normal hearing sensitivity. ANLs were also normally distributed for these children. These results indicate that ANLs measured in the preschool children with normal hearing are much like ANLs obtained in older children with normal hearing and adults with normal and impaired hearing. Lastly, the results revealed no difference between ANLs measured using speech babble and SSN. These results indicate that audiologists who do not have access to the traditional ANL stimuli can use running speech and background noise generated from the audiometer with no effect of ANLs, even for preschool-aged children. REFERENCES American Academy of Pediatrics. (2009) Caring for Your Baby and Young Child: Birth to age 5. USA: Bantam Books. American National Standards Institute. (1999) Maximum Permissible Ambient Noise Levels for Audiometric Test Rooms. (ANSI S3. 1-1999). New York: American National Standards Institute. American Speech-Language-Hearing Association. (n.d.) Development: Four to Five Years. Retrieved from http://www.asha.org/ public/speech/development/45.htm. American Speech-Language-Hearing Association. (2004) Guidelines for the Audiologic Assessment of Children From Birth to 5 Years of Age. Rockville, MD: Author. Boyle GJ. (1991) Does item homogeneity indicate internal consistency or item redundancy in psychometric scales? Pers Individ Dif 12:291–294. Freyaldenhoven MC, Smiley DF. (2006) Acceptance of background noise in children with normal hearing. J Ed Audiol 13:27–31. Freyaldenhoven MC, Smiley DF, Muenchen R, Konrad T. (2006) Acceptable noise level: reliability measures and comparison to preference for background sounds. J Am Acad Audiol 17:640–648. Gordon-Hickey S, Moore R. (2008) Acceptance of noise with intelligible, reversed, and unfamiliar primary discourse. Am J Audiol 17: 129–135. Harkrider AW, Smith SB. (2005) Acceptable noise level, phoneme recognition in noise, and measures of auditory efferent activity. J Am Acad Audiol 16:530–545. Jerger S, Lewis S, Hawkins J, Jerger J. (1980) Pediatric speech intelligibility test. I. Generation of test materials. Int J Pediatr Otorhinolaryngol 2:217–230. Jerger S, Jerger J, Lewis S. (1981) Pediatric speech intelligibility test. II. Effect of receptive language age and chronological age. Int J Pediatr Otorhinolaryngol 3:101–118. Jerger S, Jerger J. (1982) Pediatric speech intelligibility test: performance-intensity characteristics. Ear Hear 3:325–334. Jerger S, Jerger J, Abrams S. (1983) Speech audiometry in the young child. Ear Hear 4:56–66. Kawell ME, Kopun JG, Stelmachowicz PG. (1988) Loudness discomfort levels in children. Ear Hear 9:133–136.
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Macpherson BJ, Elfenbein JL, Schum RL, Bentler RA. (1991) Thresholds of discomfort in young children. Ear Hear 12:184–190. Moore R, Gordan-Hickey S, Jones A. (2011) Most comfortable listening levels, background noise levels, and acceptable noise levels for children and adults with normal hearing. J Am Acad Audiol 22:286–293.
Plyler PN, Bahng J, von Hapsburg D. (2008) The acceptance of background noise in adult cochlear implant users. J Speech Hear Lang Res 51:502–515. Rogers DS, Harkrider AW, Burchfield SB, Nabelek AK. (2003) The influence of listener’s gender on the acceptance of background noise. J Am Acad Audiol 14:372–382.
Nabelek AK, Freyaldenhoven MC, Tampas JW, Burchfield SB, Muenchen RA. (2006) Acceptable noise level as a predictor of hearing aid use. J Am Acad Audiol 17:626–639.
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Nabelek AK, Tucker FM, Letowski TR. (1991) Toleration of background noises: relationship with patterns of hearing aid use by elderly persons. J Speech Hear Res 34:679–685.
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