AIDS Care, 2015 Vol. 27, No. 8, 1037–1041, http://dx.doi.org/10.1080/09540121.2015.1021746
Hearing assessment data in HIV-infected and uninfected children of Cape Town, South Africa Peter Torre IIIa*, Alyssa Cooka, Haley Elliottb, Gouwa Dawoodc and Barbara Laughtond a School of Speech, Language, and Hearing Sciences, San Diego State University, San Diego, CA, USA; bTygerberg Children’s Hospital, Cape Town, South Africa; cDivision of Speech, Language and Hearing Therapy, Stellenbosch University, Cape Town, South Africa; dDepartment of Paediatrics and Child Health, Stellenbosch University and Tygerberg Children’s Hospital, Cape Town, South Africa
(Received 10 October 2014; accepted 18 February 2015) Researchers are showing that the rate of hearing loss in children with perinatal HIV infection (PHIV) is higher than in HIV-unexposed, uninfected children. These data, however, have been collected mostly in the USA; extensive hearing data from low- and middle-income countries are lacking. The purpose of this study was to collect audiometric data in PHIV and HIV-uninfected children living in Cape Town, South Africa. Questionnaire data along with distortion product otoacoustic emissions (DPOAEs) and pure-tone testing were completed. Hearing loss was determined using the puretone thresholds defined as a pure-tone average (PTA) of 500, 1000, 2000, and 4000 Hz of >15 dB HL in the poorer ear. All data were compared between PHIV and HIV-uninfected children. Sixty-one (37 PHIV and 24 HIV-uninfected) children had hearing data. HIV status was not significantly associated with DPOAEs. The rate of conductive hearing loss was 11.5%; five PHIV and two HIV-uninfected children. The rate of any hearing loss was higher in PHIV children, but this difference was not statistically significant. PHIV children had a significantly higher mean PTA in the poorer ear than HIV-uninfected children. Conductive type of hearing loss was more common than sensorineural hearing loss. The underlying cause of hearing loss in the present study therefore remains unclear. Future research should include an examination of auditory neural function in an effort to determine the possible reason for differences in hearing. Keywords: hearing loss; children; perinatal HIV infection; distortion product otoacoustic emissions
Introduction There is an increased risk for hearing loss in HIVinfected children (Chao et al., 2012; Taipale et al., 2011), including children with perinatal HIV infection (PHIV) and in perinatally HIV-exposed, uninfected children, compared with HIV-uninfected children (Torre et al., 2012). Early identification of pediatric hearing loss is essential for optimal language and educational outcomes (Yoshinaga-Itano & Apuzzo, 1998; YoshinagaItano, Sedey, Coulter, & Mehl, 1998). Otoacoustic emissions (OAEs) represent the outer hair cell response, within the cochlea, to external acoustic stimuli and are measured in the ear canal (Brownell, 1990). This objective measure provides an underlying subclinical assessment of auditory function, which is important in PHIV children. Recently, it was reported that HIV infection was not significantly associated with poorer distortion product OAEs (DPOAEs; Torre et al., 2014), but OAEs have been used to screen for hearing loss in newborns born to HIV-infected mothers (Manfredi, Zuanetti, Mishima, & Granzotti, 2011; Olusanya, Afe, & Onyia, 2009). The purpose of this study was to evaluate two components of the hearing mechanism in PHIV and HIVuninfected children. These components were outer hair
*Corresponding author. Email: [email protected] © 2015 Taylor & Francis
cell function using DPOAEs and the entire auditory system using pure-tone testing.
Methods Participants Parents or guardians of children between 4 and 14 years of age attending infectious disease or general pediatric outpatient clinics at Tygerberg Children’s Hospital, Cape Town, South Africa were invited to participate. Children 14 years are rarely seen at pediatric clinics. Procedures Ethical approval was obtained from the San Diego State University Institutional Review Board and Stellenbosch University Health Research Ethics Committee (N12/10/ 069). Written informed consent was obtained from the child’s parent or guardian in person and in their home language. Children ≥7 years provided assent. The research team was: a pediatrician who identified eligible participants and collected health-related data; audiology students who performed initial procedures;
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two certified audiologists who completed the hearing protocol in a sound-treated room; and research assistants who obtained consent to participate, assisted with translation, and completed questionnaires. Assessments were completed at one visit. Demographic information using questionnaires was obtained from parents or guardians. HIV viral load, CD4%, and CD4 cell count data, collected within six months of hearing testing, were obtained from medical records. Otoscopy and tympanometry measures were completed before hearing testing. DPOAEs (GSI 70 Automated OAE Screener) were measured using a screening protocol at 2000, 3000, and 4000 Hz at 65/55 dB SPL. Pure-tone air-conduction (AC) threshold testing across a 250–8000 Hz octave frequency range was completed. For children ≤5 years, the frequency range was 500– 4000 Hz in octave steps. Bone conduction (BC) thresholds were obtained in octave steps from 250 to 4000 Hz when AC thresholds were ≥20 dB HL. Hearing loss was determined using the pure-tone AC thresholds defined as a pure-tone average (PTA) of 500, 1000, 2000, and 4000 Hz of >15 dB HL in the poorer ear. Unilateral hearing loss was defined as one normal ear and one ear with hearing loss. Conductive hearing loss was defined as a ≥15 dB difference between AC thresholds and BC thresholds at two of the four frequencies tested in either ear. Statistical methods Proportion of hearing loss between groups was compared using Fisher’s exact test whereas PTA data were evaluated using Wilcoxon rank-sum tests. DPOAE data were analyzed using a mixed analysis of variance with frequency as the “within-subjects” variable and HIV status as the “between-subjects” variable. Risk factors for hearing loss were examined by fitting logistic regression models to obtain odds ratios (ORs) and 95% confidence intervals (CIs). For PHIV children, the associations between hearing loss and HIV disease severity and treatment approach were evaluated. Two-sided p values
Hearing assessment data in HIV-infected and uninfected children of Cape Town, South Africa Peter Torre IIIa*, Alyssa Cooka, Haley Elliottb, Gouwa Dawoodc and Barbara Laughtond a School of Speech, Language, and Hearing Sciences, San Diego State University, San Diego, CA, USA; bTygerberg Children’s Hospital, Cape Town, South Africa; cDivision of Speech, Language and Hearing Therapy, Stellenbosch University, Cape Town, South Africa; dDepartment of Paediatrics and Child Health, Stellenbosch University and Tygerberg Children’s Hospital, Cape Town, South Africa
(Received 10 October 2014; accepted 18 February 2015) Researchers are showing that the rate of hearing loss in children with perinatal HIV infection (PHIV) is higher than in HIV-unexposed, uninfected children. These data, however, have been collected mostly in the USA; extensive hearing data from low- and middle-income countries are lacking. The purpose of this study was to collect audiometric data in PHIV and HIV-uninfected children living in Cape Town, South Africa. Questionnaire data along with distortion product otoacoustic emissions (DPOAEs) and pure-tone testing were completed. Hearing loss was determined using the puretone thresholds defined as a pure-tone average (PTA) of 500, 1000, 2000, and 4000 Hz of >15 dB HL in the poorer ear. All data were compared between PHIV and HIV-uninfected children. Sixty-one (37 PHIV and 24 HIV-uninfected) children had hearing data. HIV status was not significantly associated with DPOAEs. The rate of conductive hearing loss was 11.5%; five PHIV and two HIV-uninfected children. The rate of any hearing loss was higher in PHIV children, but this difference was not statistically significant. PHIV children had a significantly higher mean PTA in the poorer ear than HIV-uninfected children. Conductive type of hearing loss was more common than sensorineural hearing loss. The underlying cause of hearing loss in the present study therefore remains unclear. Future research should include an examination of auditory neural function in an effort to determine the possible reason for differences in hearing. Keywords: hearing loss; children; perinatal HIV infection; distortion product otoacoustic emissions
Introduction There is an increased risk for hearing loss in HIVinfected children (Chao et al., 2012; Taipale et al., 2011), including children with perinatal HIV infection (PHIV) and in perinatally HIV-exposed, uninfected children, compared with HIV-uninfected children (Torre et al., 2012). Early identification of pediatric hearing loss is essential for optimal language and educational outcomes (Yoshinaga-Itano & Apuzzo, 1998; YoshinagaItano, Sedey, Coulter, & Mehl, 1998). Otoacoustic emissions (OAEs) represent the outer hair cell response, within the cochlea, to external acoustic stimuli and are measured in the ear canal (Brownell, 1990). This objective measure provides an underlying subclinical assessment of auditory function, which is important in PHIV children. Recently, it was reported that HIV infection was not significantly associated with poorer distortion product OAEs (DPOAEs; Torre et al., 2014), but OAEs have been used to screen for hearing loss in newborns born to HIV-infected mothers (Manfredi, Zuanetti, Mishima, & Granzotti, 2011; Olusanya, Afe, & Onyia, 2009). The purpose of this study was to evaluate two components of the hearing mechanism in PHIV and HIVuninfected children. These components were outer hair
*Corresponding author. Email: [email protected] © 2015 Taylor & Francis
cell function using DPOAEs and the entire auditory system using pure-tone testing.
Methods Participants Parents or guardians of children between 4 and 14 years of age attending infectious disease or general pediatric outpatient clinics at Tygerberg Children’s Hospital, Cape Town, South Africa were invited to participate. Children 14 years are rarely seen at pediatric clinics. Procedures Ethical approval was obtained from the San Diego State University Institutional Review Board and Stellenbosch University Health Research Ethics Committee (N12/10/ 069). Written informed consent was obtained from the child’s parent or guardian in person and in their home language. Children ≥7 years provided assent. The research team was: a pediatrician who identified eligible participants and collected health-related data; audiology students who performed initial procedures;
1038
P. Torre et al.
two certified audiologists who completed the hearing protocol in a sound-treated room; and research assistants who obtained consent to participate, assisted with translation, and completed questionnaires. Assessments were completed at one visit. Demographic information using questionnaires was obtained from parents or guardians. HIV viral load, CD4%, and CD4 cell count data, collected within six months of hearing testing, were obtained from medical records. Otoscopy and tympanometry measures were completed before hearing testing. DPOAEs (GSI 70 Automated OAE Screener) were measured using a screening protocol at 2000, 3000, and 4000 Hz at 65/55 dB SPL. Pure-tone air-conduction (AC) threshold testing across a 250–8000 Hz octave frequency range was completed. For children ≤5 years, the frequency range was 500– 4000 Hz in octave steps. Bone conduction (BC) thresholds were obtained in octave steps from 250 to 4000 Hz when AC thresholds were ≥20 dB HL. Hearing loss was determined using the pure-tone AC thresholds defined as a pure-tone average (PTA) of 500, 1000, 2000, and 4000 Hz of >15 dB HL in the poorer ear. Unilateral hearing loss was defined as one normal ear and one ear with hearing loss. Conductive hearing loss was defined as a ≥15 dB difference between AC thresholds and BC thresholds at two of the four frequencies tested in either ear. Statistical methods Proportion of hearing loss between groups was compared using Fisher’s exact test whereas PTA data were evaluated using Wilcoxon rank-sum tests. DPOAE data were analyzed using a mixed analysis of variance with frequency as the “within-subjects” variable and HIV status as the “between-subjects” variable. Risk factors for hearing loss were examined by fitting logistic regression models to obtain odds ratios (ORs) and 95% confidence intervals (CIs). For PHIV children, the associations between hearing loss and HIV disease severity and treatment approach were evaluated. Two-sided p values
