Auditory Differences Between Children With and Without HIV

Despite having clinically normal hearing, research shows that children living with HIV (CLWH) in Tanzania have lower distortion product otoacoustic emissions (DPOAEs) and lower auditory brainstem responses (ABR) wave V amplitudes, compared with children without HIV.

The researchers called these differences subtle but significant, and warrant tracking auditory function and development outcomes in CLWH.

The findings of this study, which was published in JAMA Network Open, are consistent with previous findings among young adults with HIV.

This study included 340 children recruited from an infectious disease center in Dares Salaam, Tanzania. Children were aged between 3 and 9 years with clinically normal hearing, type A tympanograms bilaterally, and air-conduction thresholds of 20 dB HL or less from 0.5 to 8 kHz.

Of this group, 141 children had HIV, with a mean (SD) age of 7.24 (1.67) years. The mean age among the 199 children without HIV was almost identical at 7.26 (1.44) years. The 2 groups also did not differ significantly in static immittance or air-conduction thresholds.

At the infectious disease center, these participants or their parent or guardian completed a series of questionnaires, which gathered data on hearing ability and general health. They also covered ear pathology and asked about birth history, education, antiretroviral therapy, gentamicin exposure, and use of other ototoxic drugs.

Peripheral auditory assessment protocols included:

• Otoscopy to ensure a clear ear canal, and cerumen removal if there was a substantial obstruction that could impede auditory measures
• Tympanometry performed at 226 Hz by a Madsen Otoflex 100
• Pure-tone audiometry performed using Creare LLC’s wireless automated hearing test system
• Measurement of pure-tone air conduction thresholds in octaves from 0.5 to 8 kHz using a modified Hughson-Westlake procedure
• Collection of DPOAEs using Creare LLC’s system at f2 values of 1.5, 2, 3, 4, 6, and 8 kHz using an f2 to f1 ratio of 1.2, and L1/L2 values of 65/55 dB sound pressure level
• ABR measurements in the right ear, recorded by an Intelligent Hearing Systems SmartEP

As expected by the researchers, mixed-effects models showed no difference between the 2 groups on static immittance or air-conduction thresholds.

However, CLWH had significantly decreased DPOAE amplitudes at 6.0 and 8.0 kHz in both left and right ears, and significantly reduced ABR wave V amplitude for the slow and fast click rate, compared with children without HIV.

HIV status was associated with approximately 1.4 dB (95% CI, −3.28 to 0.30 dB) to 3.8 dB (95% CI, 6.03 to −1.99 dB) lower DPOAE amplitudes at 6 and 8 kHz bilaterally. HIV status was also independently association with a 0.28 μV (95% CI, 0.01-0.33 μV) lower ABR wave V amplitudes in the right ear.

“The magnitude of these differences was small, but results suggest an early and consistent association between HIV infection or treatment and outer hair cell and auditory brainstem responses in children as young as 3 years,” the study authors said.

They also said these findings were consistent with those among young adults with and without HIV in 2 main ways. First, the directionality of change is similar, as young adults with HIV have been shown to have smaller DPOAEs and ABR amplitude profiles compared with their HIV-negative counterparts. Second, they said the only significant differences on ABR are related to amplitude, with significantly different ABR latencies between groups in either analysis.

At the same time, there are also key differences between this study and the study with young adults. First, among participants with HIV, young adults showed impaired DPOAEs across a broader frequency range compared with children, potentially due to deterioration of the outer hair cells of the cochlea as age increases. Second, the statistically significant components of the ABR profile differed between studies, with a significantly smaller wave I in young adults with HIV, and a smaller wave V amplitude among CLWH, which could be caused by multiple factors.

According to the authors, future research is needed to examine several possible relationships noted in this study, including potential effects of HIV on central auditory pathways, effects of central nervous system changes on DPOAEs, and effects of the cochlea on subclinical peripheral deficits.

“These subclinical auditory deficits in CLWH highlight the importance of characterizing any effects on cognitive and literacy development,” the authors said. “Long-term studies are also needed to understand how these subtle deficits in peripheral auditory function evolve in combination with concurrent drug therapies, comorbid conditions, and aging.”

Reference

Niemczak CE, Ealer C, Fellows A, et al. Peripheral auditory function in Tanzanian children living with HIV with clinically normal hearing. JAMA Netw Open. 2023;6(3):e233061. doi:10.1001/jamanetworkopen.2023.3061