Bishara Awwad, Ph.D.
The Research
Mass Eye and Ear
Auditory-limbic circuit dynamics as therapeutic targets in hyperacusis
Our research addresses a critical gap in understanding the neural basis of hyperacusis by focusing on the emotional dimensions of sound hypersensitivity. Previous work has established that cochlear damage leads to hyperexcitability throughout the central auditory pathway, but our approach uniquely focuses on the circuit-specific mechanisms that link auditory processing to emotional responses.
Specifically, we investigate how noise-induced hearing loss affects two parallel pathways to the lateral amygdala: the cortico-amygdalar (CAmy) and thalamo-amygdalar (TAmy) projections. This pathway- specific investigation represents a novel approach to understanding hyperacusis, as it targets the precise neural circuits that may mediate both the perceptual and emotional components of this disorder.
Long-term goal: This research investigates why people with hearing loss sometimes develop hyperacusis—a condition where everyday sounds become overwhelmingly loud and can even cause physical pain. We're examining brain pathways that connect hearing centers to the amygdala, a region involved in emotional responses. Our specific aims are to: determine which brain circuits drive the heightened sound sensitivity and emotional distress in hyperacusis; test whether targeted stimulation at 40 Hz can restore more normal sound processing; and explore whether measurable physiological responses, such as pupil changes, correlate with symptom severity.
Hyperacusis affects millions of people and currently has no approved treatments. This work may contribute to future therapeutic approaches in several ways: The findings suggest that interventions targeting central brain circuits could potentially help even when inner ear damage cannot be reversed—similar to approaches in chronic pain management that focus on the nervous system rather than the original injury site; the 40 Hz stimulation protocol showing sustained effects in our animal model could inform development of non-invasive stimulation approaches for human patients, though significant additional research would be needed to translate these findings to clinical practice.
Generously funded by Hyperacusis Research
