Sympathectomy is an effective treatment of certain forms of of tinnitus, such as that which occurs in Meniere's disease and it has therefore been suggested that the sympathetic nervous system may modulate (increase) the sensitivity of cochlear hair cells.
Aage R. Moller:
Hearing: Anatomy, Physiology, and Disorders of the Auditory System
Academic Press, 2006
ISBN: 0123725194