Primary afferent dendrite degeneration as a cause of tinnitus.
Chronic tinnitus affects millions of people, but the mechanisms responsible for the development of this abnormal sensory state remain poorly understood. This study examined the type and extent of cochlear damage that occurs after acoustic trauma sufficient to induce chronic tinnitus in rats. Tinnitus was evaluated by using a conditioned suppression method of behavioral testing. Cochlear damage was assessed 6 months after acoustic trauma. There was minimal loss of inner and outer hair cells in the exposed cochleas of subjects demonstrating evidence of tinnitus. However, a significant loss of large-diameter fibers in the osseous spiral lamina of exposed cochleas of trauma subjects was observed. The significance of this finding in the context of a model of tinnitus is discussed.
Bauer
Carol A
CA
Division of Otolaryngology Head and Neck Surgery, Southern Illinois University School of Medicine, Springfield, Illinois 62794, USA. cbauer@siumed.edu
Brozoski
Thomas J
TJ
Myers
Kristin
K
D000161:Acoustic Stimulation; D000818:Animals; D001306:Auditory Pathways / Q000473:pathology*; D002908:Chronic Disease; D003051:Cochlea / Q000473:pathology*; D003712:Dendrites / Q000473:pathology*; D004195:Disease Models, Animal; D006198:Hair Cells, Auditory / Q000473:pathology; D008297:Male; D009410:Nerve Degeneration / Q000473:pathology*; D051381:Rats; D020318:Rats, Long-Evans; D014012:Tinnitus / Q000473:pathology*