The functional neuroanatomy of tinnitus: evidence for limbic system links and neural plasticity.
We used PET to map brain regions responding to changes in tinnitus loudness in four patients who could alter tinnitus loudness by performing voluntary oral facial movements (OFMs). Cerebral blood flow was measured in four patients and six controls at rest, during the OFM, and during stimulation with pure tones. OFM-induced loudness changes affected the auditory cortex contralateral to the ear in which tinnitus was perceived, whereas unilateral cochlear stimulation caused bilateral effects, suggesting a retrocochlear origin for their tinnitus. Patients, compared with controls, showed evidence for more widespread activation by the tones and aberrant links between the limbic and auditory systems. These abnormal patterns provide evidence for cortical plasticity that may account for tinnitus and associated symptoms. Although audiologic symptoms and examinations of these patients were typical, the unusual ability to modulate tinnitus loudness with an OFM suggests some caution may be warranted in generalizing these findings.
Lockwood
A H
AH
Center for Positron Emission Tomography, Department of Neurology, VA Western New York Health Care System, and State University of New York, University at Buffalo, 14215, USA.
Salvi
R J
RJ
Coad
M L
ML
Towsley
M L
ML
Wack
D S
DS
Murphy
B W
BW
D000161:Acoustic Stimulation; D000328:Adult; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000000981:diagnostic imaging / Q000503:physiopathology; D003056:Cochlear Nerve / Q000503:physiopathology; D005260:Female; D006801:Humans; D008032:Limbic System / Q000000981:diagnostic imaging / Q000503:physiopathology*; D008297:Male; D009473:Neuronal Plasticity; D014012:Tinnitus / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D014055:Tomography, Emission-Computed