HIV may affect the brain’s ability to process sound, according to new research. 

Even with effective antiretroviral therapy (ART), HIV can still damage the central nervous system. According to new research by a collaboration between Dartmouth College’s Geisel School of Medicine and Northwestern University’s Auditory Neuroscience Laboratory, HIV may disrupt auditory-neurophysiological responses to certain speech cues. 

The study, which was published in Clinical Neurophysiology, was composed of 68 HIV-positive adults and 59-HIV negative adults living in Dar es Salaam, Tanzania. The researchers measured brain waves using the noninvasive speech-evoked frequency-following response (FFR) technique. As common speech sounds like “ba,” “da,” and “ga,” are played into the ear, brain waves are recorded from scalp electrodes. 

Researchers were able to use FFR to determine that even though HIV-positive adults performed normally on hearing tests, certain speech cues were disrupted. According to the press release, this indicates that the hearing problems are grounded in the central nervous system. 

"When the brain processes sound, it's not like a volume knob where all of the acoustic ingredients are either processed well or poorly…With the FFR, we're able to see which aspects of auditory processing are affected or diminished and ask, 'Is there a specific neural signature that aligns itself with HIV,'" study co-author and Hugh Knowles professor of Communication Sciences and Neurobiology at Northwestern Nina Kraus, PhD, said in the press release. 

According to the press release, researchers hope that FFR could not only be an effective tool in studying HIV, but also other disorders that affect the brain, such as Alzheimer disease and Zika virus infection. 

New study shows how tests of hearing can reveal HIV's effects on the brain (News Release); Hanover, New Hampshire; June 29, 2020; EurekAlert!; Accessed June 30, 2020