A major theme of the research conducted in the lab is the study of auditory processing disorders, especially tinnitus. Tinnitus or ringing in the ears is often associated with hearing loss but not every person with hearing loss develops tinnitus. It is estimated that nearly 50 million Americans experience it. Dr. Husain has initiated MRI experiments to understand why some individuals with hearing loss develop tinnitus whereas others do not. The lab continues to study the neural bases of tinnitus using behavioral, modeling, and MRI tools. By using detailed audiological assessments and behavioral studies, we plan to link more subjective markers of tinnitus with a greater amount of objective data obtained using MRI. The computational modeling will be used to account for both the behavioral and MRI data. There is no cure for tinnitus, although there are therapies that alleviate it in some cases. The goal of my research is to contribute to a more desirable evaluation of current therapies and to the development of new treatments.
We have compiled a brief description of our current main findings from the research that has been conducted in our lab the past 10 years.
Sound Tolerance Disorders
The lab conducts experiments to delineate the neurological, psychological and audiological basis of sound tolerance disorders (DST) such as misophonia and hyperacusis. Misophonia is a DST that causes patients to have an involuntary negative emotional and physical reaction to certain sounds. Hyperacusis is characterized by an increased sensitivity to everyday sounds that causes significant distress and interferes with daily activities. Dr. Husain has begun MRI experiments, including functional and resting state imaging, to investigate the neural basis of these disorders. Furthermore, detailed audiological and psychological evaluations performed in the lab aid in understanding the audiological characteristics and psychological impact of these disorders. This comprehensive understanding of DST will aid in the development of models for their mechanisms.
Dr. Husain has generated models of auditory perception in the cortex and has conducted fMRI studies to verify the models (Husain et al., 2004). The model processes simple non-speech sounds such as tonal sweeps. The model has been used to investigate the neural bases of auditory continuity illusion (Husain et al., 2005).
Categorization stands at the junction of perception and higher-level cognition. It allows us to investigate the next-step of processing beyond perception. Dr. Husain has conducted fMRI (Husain et al., 2006a) and functional connectivity studies (Husain et al., 2006b) into the categorization of simple speech (vowels, CV syllables) and non-speech sounds (tones, tonal sweeps). She has also investigated the categorization of sign language and other manual gestures by both Deaf signers and hearing non-sginers (manuscript submitted).
In the past Dr. Husain has studied the acquisition of phonemes of a second language by adult learners, specifically the acquisition of American English vowels by Spanish speakers. More recently, the lab is initiating studies to understand the acquisition of Mandarin Chinese tones by older adults.