Age-Related Hearing Loss and Memory

Hearing loss is the third most common chronic physical condition in the United States. The negative effects of hearing loss are so much greater than what we might think. The downside of hearing loss is not just missing some words that are spoken or not being able to understand what is being said. Studies have shown that hearing loss has a significant impact on a person's brain anatomy, cognition, and social life.

A decrease in auditory input has been shown to cause a decrease gray matter volume in the auditory cortex (Peelle et al., 2011). Atrophy of the auditory cortex may have downstream effects in the regions of the brain associated with speech processing and decrease the cognitive resources to which a person has access. Another significant side effect of hearing loss is increased social isolation, which has been directly related to poor diet, increased alcohol use, depression, and even earlier onset of dementia.  

Physiological Measures of Cognitive Effort

It is known that an increase in cognitive effort directly leads to an increase in dilation of the pupil of the eye. Our lab uses the latest eye-tracking software to measure pupil size as participants listen to and recall speech. Studies have shown that as a person increases their cognitive effort, the size of their pupil increases. Using this parameter, we are able to use pupillometry to study the amount of effort a person is putting in when completing a given task. In our lab, we change various prosodic features of speech and analyze changes in pupil size. By looking at the pupil size, we are able to determine how much cognitive effort is needed to overcome changes to certain prosodic features.

Cochlear Implants and Speech Comprehension

Cochlear implants are electronic hearing devices that stimulate nerves of the inner ear in response to auditory input. Older adults have received cochlear implants with a high rate of success, with immediate positive results and improvement over the first few months after practice and tune-ups from their audiologist. However, despite tests indicating that the implants are functioning correctly and the patients are hearing well, cochlear implant users indicate that they are exhausted after just a few minutes of conversation. This fatigue seems to be related to an increase in cognitive effort on the part of the cochlear implant user.

In collaboration with NYU Langone's Cochlear Implant Center, we are studying how much cognitive effort cochlear implant users need to put in for speech comprehension in comparison with normal-hearing adults. Our colleague's in NYU study cochlear implant users while our lab performs studies on older adults with normal hearing, older adults with hearing loss, and a control population of young normal hearing adults.