Perceptualand Motor Skills, 1991, 73, 880-882.
O Percepolal and Motor Skills 1991
FREQUENCY AND INTENSITY EFFECTS UPON TEMPORAL AND AERODYNAMIC ASPECTS O F VOCAL FOLD DIADOCHOKINESIS ' HERBERT A. LEEPER Department of Communicatiue Disordm University of Western Ontario
AND
ELIZABETH JONES Private Practice Winnipeg, Manitoba
Summary.-The present study of vocal fold diadochokinesis in 18 young adult women yielded statistically significant differences in intensity (at percentiles 25%, 50%, 75% of range) of production for vowel / A / repetition rate. In addition, there were statistically significant differences for vocal frequency and intensity effects for airflow rate through the vocal folds at the 25th, 50th, and 75th percentile points within the functional vocal range. Clinical applications of the data are suggested.
Diadochokinesis is the function of arresting one motor impulse and substituting one that is diametrically opposed. It is commonly examined through the use of rapid alternating motions. While such assessment is often used clinically by speech-language pathologists to assess motor control of the oral articulators (I), few data (6) are available to characterize the laryngeal mechanism. Information concerning the timing and amount of air used during rapid voluntary opening and closing of the vocal folds would be useful in determining the functional integrity (efficiency) of the voice-producing system during changes within the total range of vocal frequency and loudness production. Since few data are available, the present study was designed to examine the characteristics of vocal-fold opening and closing rate and the amount of air passing through the vocal folds during vowel / A / repetition at several levels (soft, moderate, loud) of vocal loudness and vocal frequency range (percentiles 25th, 50th, 75th) in young adult women.
Method Subjects.-Subjects were 18 healthy, young adult women volunteers (20 to 25 years old, M = 23.3 yr.) with no history of respiratory, neurological, or hearing difficulties. Peak inspiratory volume was measured with a wet spirometer (Stead-Wells, Model P-1400) while simultaneous pneumographic patterns (Sanborn, Model 108) fmm the upper rib cage motion were obtained and disolaved Model 184A). These measures were used to . * on an oscilloscooe . (Hewlett-Packard. . ensure depth and consistency of inhalation for the speech tasks. Vocal intensity range was recorded with a microphone (Electrovoice, Model 664) and measuring amplifier (Bruel & Kjaer, Model 2607). The intensity levels were recorded visually by the examiners from the W meter of the measuring amplifier. Frequency range was recorded with a microphone and associated electronic variable frequency filter (Krohn-Hite, Model 3202) and displayed on a commercial counterltimer (Hewlett-Packard, Model 5300A) as digital frequency values. A commercially available facemask-pneumota~ho~raph (Sanborn, Model A-959), differential pressure transducer (Honeywell, Model PM 15E), and amplifier (Honeywell, Model 113) were connected in series to one 'Requests for reprints should be addressed to Herbert A. Leeper, Ph.D., Department of Communicative Disorders, Elborn College, University of Western Ontario, London, Ontario N6G 1H1, Canada.
VOCAL FOLD DIADOCHOKINESIS: VOCAL FREQUENCY, INTENSITY
881
channel of an optical oscillograph (Honeywell, Model 2206) to record and display transglottal airflow for each subject during the vowel / A / repetition task. The microphone was placed 6 cm distal to the mouth-facemask apparatus to record acoustic voice production simultaneously with airflow measures and was displayed on the second channel of the optical oscillograph. The data on this channel were used to establish the production rate for each of the experimental conditions. Procedure.-Each subject inhaled deeply to a point of depth of inspiration (100% Inspiratory Reserve Volume) (IRV) just prior to the vowel repetitions. The 25th, 50th, and 75th percentiles of each subject's intensity and frequency range were calculated from each of their predetermined minimum and maximum intensity and frequency levels. The order of presentation of the nine levels was counterbalanced. Each subject produced the vowel / A / as rapidly as possible with the facemask-pneumotachograph system for each of the combinations of the three frequency and three intensity percentile levels. Three 5-sec. trials of each of the nine intensity-frequency levels were recorded. Retrials were required if frequency and intensity varied by more than f 2%. The middle 3-sec. segments of each of the three trials were measured and averaged by one of the examiners to produce one score for each condition for both peak airflow rate and rate of production of the vowel /A/.
Results Means and standard deviations for rate of vowel / A / production for the nine intensity-frequency conditions are presented in Table 1. A multifactor analysis of variance (7) indicated a significant difference (F,,,,= 6.34, p = .01) across the intensity conditions. Post hoc testing (Scheffk) indicated significant differences in production rate (p = .01) between the 25th and 75th and the 50th and 75th percentiles of the intensity range. TABLE 1 MEANSAND STANDARD DEVIATIONSFORTHE NINEFREQUENCY-INTENSITY CONDITIONS FOR (VFDDK) Fhm m SYLLABLES PER SECOND AND VOCALFOLDDIADOCHOKINETIC TRANSGLOTTAL h o w RATE IN CUBICC E N T ~ T E RPER S SECOND Percentiles Intensity, dB 25th 50th 75th
25th Percentiles Rate Airflow Rate Airflow Rate Airflow
Frequency, Hz 50th Percentiles
75th Percentiles
M
SD
M
SD
M
SD
3.0 151.6 3.5 165.6 2.4 281.0
.7 74.0 1.0 69.0 1.0 184.0
2.8 200.6 2.7 292.1 2.5 284.6
1.0 78.0 1.O 256.0 1.0 183.0
2.7 177.9 2.8 252.0 2.2 333.8
.7 130.0 1.1 130.0 .9 285.0
The fastest syllable rate occurred at the 50th percentile of intensity (3.5 syll./sec.), while the slowest rate was found at the 75th percentile of both intensity and frequency (2.2 1 syll./sec.). There were no significant differences for any of the frequency conditions. Means and standard deviations for transglottal airflow rate for the nine intensity-frequency conditions are also presented in Table 1. A separate anal-
882
H. A. LEEPER & E. JONES
ysis of variance inhcated a significant difference in airflow rate by intensity condition (F,,,,= 8.27, p = .01) and by frequency (F,,,,= 3.69, p = .05). Post hoc testing (Scheff6) of the main effects indicated significant differences ( p = .05) between the 25th and 50th percentiles of frequency, and between the 25th and 50th and the 50th and 75th percentiles of intensity. The greatest average airflow rate occurred at the 75th percentiles of frequency and intensity (338.8 cclsec.), while the lowest airflow rate occurred at the 25th percentiles of the frequency and intensity conditions (151.6 cclsec.). Discussion The results suggest that vocal intensity appears to be the primary controlling factor in vocal fold diadochokinetic (VFDDK) syllable rate and regulation of airflow through the glottis during vowel / A / production. The present results support earlier research (2) which demonstrated that at low vocal frequency, glottal resistance functioned to vary intensity, while at high frequency phonation, intensity was controlled by airflow rate via expiratory muscle force. At the middle of the vocal frequency range, both flow rate and glottal resistance increased linearly with increased vocal intensity. Similar findings were reported with indirect measures of laryngeal airway resistance with alterations in sound pressure level (intensity) (3). The use of VFDDK as a clinical tool in the assessment of laryngeal function appears warranted provided the parameters (intensity of production) under which the task is are specified. Knowledge of VFDDK permits further characterization of an individual's laryngeal neuromuscular integrity. Changes in range and speed of vocal fold movement will be reflected in changes in production rate, durational patterns, and transglottal airflow rate. Information concerning the efficiency of laryngeal valving allows greater efficacy in describing disorders which may involve several neuromuscular valves, e.g., laryngeal, velopharyngeal (5). Further research is necessary for a larger and more diversely aged sample of normal-speaking male and female subjects and individuals wrth a variety of laryngeal disorders (4). REFERENCES 1. DARLEY, F., ARONSON,A , , & BROWN,J. (1975) Motor speech disorders. Philadelphia, PA: Saunders. 2. I s s m , N. (1964) Regulatory mechanism of voice intensity variation. Journal of Speech and Hearing Research, 7, 17-23. D. (1984) Consistency of laryngeal airway resistance in adult 3. LEEPER,H. A,, & GRAVES, women. Journal of Communication Disorders, 17, 153-163. 4. LEEPER,H. A , , HEENEMAN, H., & REYNOLDS,C. (1991) Vocal function following vertical hemilaryngectomy: a preliminary investigation. Iournal of Otolaryngology, 19, 62-67. 5. NETSELL, R., & DANIEL,B. (1979) Dysarthria in adults: physiologic approach to rehabilitation. Archives of Physical Medicine and Rehabilitation, 60, 502-508. 6 . SHANKS,S. J. (1966) An investigation of the nature of vocal fold diadochokinesis. Unpublished Ph.D. dissertation, Louisiana State Umver 7. WINER, B. J. (1970) Statisticalprinciples in experimental derrgn New York: McGraw-Hd. Pp. 228-241.
Accepted November 11, 1991.
O Percepolal and Motor Skills 1991
FREQUENCY AND INTENSITY EFFECTS UPON TEMPORAL AND AERODYNAMIC ASPECTS O F VOCAL FOLD DIADOCHOKINESIS ' HERBERT A. LEEPER Department of Communicatiue Disordm University of Western Ontario
AND
ELIZABETH JONES Private Practice Winnipeg, Manitoba
Summary.-The present study of vocal fold diadochokinesis in 18 young adult women yielded statistically significant differences in intensity (at percentiles 25%, 50%, 75% of range) of production for vowel / A / repetition rate. In addition, there were statistically significant differences for vocal frequency and intensity effects for airflow rate through the vocal folds at the 25th, 50th, and 75th percentile points within the functional vocal range. Clinical applications of the data are suggested.
Diadochokinesis is the function of arresting one motor impulse and substituting one that is diametrically opposed. It is commonly examined through the use of rapid alternating motions. While such assessment is often used clinically by speech-language pathologists to assess motor control of the oral articulators (I), few data (6) are available to characterize the laryngeal mechanism. Information concerning the timing and amount of air used during rapid voluntary opening and closing of the vocal folds would be useful in determining the functional integrity (efficiency) of the voice-producing system during changes within the total range of vocal frequency and loudness production. Since few data are available, the present study was designed to examine the characteristics of vocal-fold opening and closing rate and the amount of air passing through the vocal folds during vowel / A / repetition at several levels (soft, moderate, loud) of vocal loudness and vocal frequency range (percentiles 25th, 50th, 75th) in young adult women.
Method Subjects.-Subjects were 18 healthy, young adult women volunteers (20 to 25 years old, M = 23.3 yr.) with no history of respiratory, neurological, or hearing difficulties. Peak inspiratory volume was measured with a wet spirometer (Stead-Wells, Model P-1400) while simultaneous pneumographic patterns (Sanborn, Model 108) fmm the upper rib cage motion were obtained and disolaved Model 184A). These measures were used to . * on an oscilloscooe . (Hewlett-Packard. . ensure depth and consistency of inhalation for the speech tasks. Vocal intensity range was recorded with a microphone (Electrovoice, Model 664) and measuring amplifier (Bruel & Kjaer, Model 2607). The intensity levels were recorded visually by the examiners from the W meter of the measuring amplifier. Frequency range was recorded with a microphone and associated electronic variable frequency filter (Krohn-Hite, Model 3202) and displayed on a commercial counterltimer (Hewlett-Packard, Model 5300A) as digital frequency values. A commercially available facemask-pneumota~ho~raph (Sanborn, Model A-959), differential pressure transducer (Honeywell, Model PM 15E), and amplifier (Honeywell, Model 113) were connected in series to one 'Requests for reprints should be addressed to Herbert A. Leeper, Ph.D., Department of Communicative Disorders, Elborn College, University of Western Ontario, London, Ontario N6G 1H1, Canada.
VOCAL FOLD DIADOCHOKINESIS: VOCAL FREQUENCY, INTENSITY
881
channel of an optical oscillograph (Honeywell, Model 2206) to record and display transglottal airflow for each subject during the vowel / A / repetition task. The microphone was placed 6 cm distal to the mouth-facemask apparatus to record acoustic voice production simultaneously with airflow measures and was displayed on the second channel of the optical oscillograph. The data on this channel were used to establish the production rate for each of the experimental conditions. Procedure.-Each subject inhaled deeply to a point of depth of inspiration (100% Inspiratory Reserve Volume) (IRV) just prior to the vowel repetitions. The 25th, 50th, and 75th percentiles of each subject's intensity and frequency range were calculated from each of their predetermined minimum and maximum intensity and frequency levels. The order of presentation of the nine levels was counterbalanced. Each subject produced the vowel / A / as rapidly as possible with the facemask-pneumotachograph system for each of the combinations of the three frequency and three intensity percentile levels. Three 5-sec. trials of each of the nine intensity-frequency levels were recorded. Retrials were required if frequency and intensity varied by more than f 2%. The middle 3-sec. segments of each of the three trials were measured and averaged by one of the examiners to produce one score for each condition for both peak airflow rate and rate of production of the vowel /A/.
Results Means and standard deviations for rate of vowel / A / production for the nine intensity-frequency conditions are presented in Table 1. A multifactor analysis of variance (7) indicated a significant difference (F,,,,= 6.34, p = .01) across the intensity conditions. Post hoc testing (Scheffk) indicated significant differences in production rate (p = .01) between the 25th and 75th and the 50th and 75th percentiles of the intensity range. TABLE 1 MEANSAND STANDARD DEVIATIONSFORTHE NINEFREQUENCY-INTENSITY CONDITIONS FOR (VFDDK) Fhm m SYLLABLES PER SECOND AND VOCALFOLDDIADOCHOKINETIC TRANSGLOTTAL h o w RATE IN CUBICC E N T ~ T E RPER S SECOND Percentiles Intensity, dB 25th 50th 75th
25th Percentiles Rate Airflow Rate Airflow Rate Airflow
Frequency, Hz 50th Percentiles
75th Percentiles
M
SD
M
SD
M
SD
3.0 151.6 3.5 165.6 2.4 281.0
.7 74.0 1.0 69.0 1.0 184.0
2.8 200.6 2.7 292.1 2.5 284.6
1.0 78.0 1.O 256.0 1.0 183.0
2.7 177.9 2.8 252.0 2.2 333.8
.7 130.0 1.1 130.0 .9 285.0
The fastest syllable rate occurred at the 50th percentile of intensity (3.5 syll./sec.), while the slowest rate was found at the 75th percentile of both intensity and frequency (2.2 1 syll./sec.). There were no significant differences for any of the frequency conditions. Means and standard deviations for transglottal airflow rate for the nine intensity-frequency conditions are also presented in Table 1. A separate anal-
882
H. A. LEEPER & E. JONES
ysis of variance inhcated a significant difference in airflow rate by intensity condition (F,,,,= 8.27, p = .01) and by frequency (F,,,,= 3.69, p = .05). Post hoc testing (Scheff6) of the main effects indicated significant differences ( p = .05) between the 25th and 50th percentiles of frequency, and between the 25th and 50th and the 50th and 75th percentiles of intensity. The greatest average airflow rate occurred at the 75th percentiles of frequency and intensity (338.8 cclsec.), while the lowest airflow rate occurred at the 25th percentiles of the frequency and intensity conditions (151.6 cclsec.). Discussion The results suggest that vocal intensity appears to be the primary controlling factor in vocal fold diadochokinetic (VFDDK) syllable rate and regulation of airflow through the glottis during vowel / A / production. The present results support earlier research (2) which demonstrated that at low vocal frequency, glottal resistance functioned to vary intensity, while at high frequency phonation, intensity was controlled by airflow rate via expiratory muscle force. At the middle of the vocal frequency range, both flow rate and glottal resistance increased linearly with increased vocal intensity. Similar findings were reported with indirect measures of laryngeal airway resistance with alterations in sound pressure level (intensity) (3). The use of VFDDK as a clinical tool in the assessment of laryngeal function appears warranted provided the parameters (intensity of production) under which the task is are specified. Knowledge of VFDDK permits further characterization of an individual's laryngeal neuromuscular integrity. Changes in range and speed of vocal fold movement will be reflected in changes in production rate, durational patterns, and transglottal airflow rate. Information concerning the efficiency of laryngeal valving allows greater efficacy in describing disorders which may involve several neuromuscular valves, e.g., laryngeal, velopharyngeal (5). Further research is necessary for a larger and more diversely aged sample of normal-speaking male and female subjects and individuals wrth a variety of laryngeal disorders (4). REFERENCES 1. DARLEY, F., ARONSON,A , , & BROWN,J. (1975) Motor speech disorders. Philadelphia, PA: Saunders. 2. I s s m , N. (1964) Regulatory mechanism of voice intensity variation. Journal of Speech and Hearing Research, 7, 17-23. D. (1984) Consistency of laryngeal airway resistance in adult 3. LEEPER,H. A,, & GRAVES, women. Journal of Communication Disorders, 17, 153-163. 4. LEEPER,H. A , , HEENEMAN, H., & REYNOLDS,C. (1991) Vocal function following vertical hemilaryngectomy: a preliminary investigation. Iournal of Otolaryngology, 19, 62-67. 5. NETSELL, R., & DANIEL,B. (1979) Dysarthria in adults: physiologic approach to rehabilitation. Archives of Physical Medicine and Rehabilitation, 60, 502-508. 6 . SHANKS,S. J. (1966) An investigation of the nature of vocal fold diadochokinesis. Unpublished Ph.D. dissertation, Louisiana State Umver 7. WINER, B. J. (1970) Statisticalprinciples in experimental derrgn New York: McGraw-Hd. Pp. 228-241.
Accepted November 11, 1991.
