Hearing Tests Show HIV Impacts Brain’s Ability to Process Sound

Anahita Kodali, Medical Sciences, News, Summer 2020

Figure 1: With the exception of certain Hawaiian Islands, every state in the US has some significant percentage of people with HIV. Georgia, Florida, and Louisiana have the most cases.

Image Citation: Wikimedia Commons

Acquired immunodeficiency syndrome (AIDS), the late stage of infection from the human immunodeficiency virus (HIV), is one of the world’s longest lasting and deadliest epidemics. There are 4 main stages of HIV infection. The first stage is primary infection (or acute HIV). Some people who contract HIV have mild flu-like symptoms between 2 to 4 weeks after the virus first enters the body. Next is clinical latent infection (or chronic HIV). In this stage, HIV is still present in the body and white blood cells, but most people will not have any symptoms. Even without the use of antiretroviral therapies, this stage can last several years; however, some people progress to more serious stages of the disease quickly. The third stage is symptomatic HIV infection. The virus will have destroyed so many of the body’s immune cells that people now have mild and chronic symptoms, like a cough, fever, fatigue, and weight loss. Finally, the disease progresses to AIDS. Most people in the US will never get AIDS, as constant use of antiretroviral therapies will keep the virus contained. Without treatment, HIV will progress to AIDS in 8 to 10 years. At this stage, the body’s immune system is extremely weakened, and people will have severe symptoms like sweats, high fever, swollen lymph glands, and lesions in the mouth; in addition, people are more likely to get certain diseases and cancers that an otherwise healthy person would not contract. It is ultimately fatal1.

Currently, there are about 1.2 million Americans with HIV2. This, combined with the fact that HIV is treatable if caught early, explains why it is critical to understand more about how the virus affects the body – the more scientists know, the more chances people have to get treated and live relatively normal lives. Now, researchers from Dartmouth’s Geisel School of Medicine and Northwestern’s Auditory Neuroscience Laboratory have gained insights into how HIV impacts the brain. After observing that the hearing of patients with HIV was affected, the team, led by Dr. Nina Kraus of Northwestern and Dr. Jay Buckey of Dartmouth, tested the hypothesis that HIV affects the brain’s ability to process sound rather than directly impacting the ear itself (a commonly held belief in the scientific community)3. They used a speech-evoked frequency-following response (FFR) test, in which researchers use electrodes to record brain waves while people listen to sounds4. When the team compared their collected FFR data from patients with HIV to people without HIV, they found that even though HIV-positive adults performed as expected on hearing tests, there were issues with auditory-neurophysiological responses in certain sound cues, causing the brain to process the sound incorrectly3. This allowed them to confirm that HIV impacts the brain itself, not the ears.

These findings are of great importance for the future of HIV research, as researchers will be able to further explore HIV’s complex impact on the brain. Perhaps more significantly, however, is that the team proved the value of FFR testing and research for a variety of cognitive impairments and diseases, including Alzheimer’s, concussions, and Zika virus4. Thus, in the coming years, there could be a host of new information about the brain and neurological disorders.

Bibliography

[1] HIV/AIDS. (2020, February 13). Retrieved July 06, 2020, from https://www.mayoclinic.org/diseases-conditions/hiv-aids/symptoms-causes/syc-20373524

[2] U.S. Statistics. (2020, June 30). Retrieved July 06, 2020, from https://www.hiv.gov/hiv-basics/overview/data-and-trends/statistics

[3] White-Schwoch, T., Magohe, A. K., Fellows, A. M., Rieke, C. C., Vilarello, B., Nicol, T., . . . Buckey, J. C. (2020). Auditory neurophysiology reveals central nervous system dysfunction in HIV-infected individuals. Clinical Neurophysiology,131(8), 1827-1832. doi:10.1016/j.clinph.2020.04.165

[4] The Geisel School of Medicine at Dartmouth. (2020, July 2). Tests of hearing can reveal HIV’s effects on the brain. ScienceDaily. Retrieved July 6, 2020 from www.sciencedaily.com/releases/2020/07/200702113723.htm

 

 

 

 

Bookmark the permalink.

Leave a Reply

Your email address will not be published.