A Cross-Species Approach to Understanding the Physiological Mechanisms underlying Age-related Hearing Loss
Age-related hearing loss, defined as declines in the hearing thresholds, affects more than 60% of individuals over 70 years of age. Untreated hearing loss decreases the quality of life and has also been associated with other age-related comorbidities such as cognitive impairment or Alzheimer’s disease. However, assessing hearing thresholds alone fails to capture critical aspects of real-world hearing difficulties. At the auditory periphery, in addition to sensory loss that typically affect thresholds, there is a progressive loss of synapses between the inner hair cells and the auditory nerve that is undetected by threshold assessments, earning it the moniker of ‘hidden’ hearing loss. In the central auditory pathway, synaptopathy is accompanied by compensatory changes to various neural circuits. Thus, age-related hearing loss reflects a complex mixture of degeneration and neural compensation from cochlea to cortex, which affects aged listeners, who experience problems listening in complex listening environments.
This talk will focus on studies aimed at diagnosing hidden hearing loss, understanding the central consequences of hidden hearing loss on neural coding of sounds, and the effects of cochlear synapse loss on speech understanding using a translational approach which combines studies in animal models and human clinical populations. Using non-invasive, auditory evoked potentials as the translational bridge, we study the functional aspects of age-related hearing loss with the goal of designing the next generation of objective neurophysiological biomarkers for assessing changes in hearing due to neurodegenerative processes or with therapeutic interventions.
Dr. Parthasarathy is an Assistant Professor at the University of Pittsburgh.
NACS Seminars are free and open to the public.