Regional glucose metabolic increases in left auditory cortex in tinnitus patients: a preliminary study with positron emission tomography.
OBJECTIVE
To investigate the relationship between tinnitus and glucose metabolism in auditory cortex and whether positron emission tomography (PET) can be an objective tool in measuring tinnitus.


METHODS
Eleven right-handed patients with severe tinnitus and ten right-handed control subjects participated in the 18F-FDG/PET study. Analysis with regions of interests was used to calculate asymmetry indices according to the formula: [(L-R) x 100/[(L + R) divided by 2]].


RESULTS
Glucose metabolism in the auditory cortex of tinnitus patients was asymmetric between the left and right auditory cortices, with that of the left being much higher than that of the right. The asymmetry indices of tinnitus patients was significantly higher than that of the control group (unpaired t test, P < 0.001). This revealed that the increased metabolic activity was present in the predominant left hemisphere with a significant focus on the superior and transverse temporal gyri (Brodmann areas 41 and 42, respectively corresponding to primary and secondary auditory cortex), and the results were independent of the subjective localization of the tinnitus sensation.


CONCLUSIONS
It is suggested that the increased metabolism in the left auditory cortex is related to the tinnitus sensation. PET is capable of providing objective evidence for tinnitus and may be used as a potential tool in measuring tinnitus.
Wang
H
H
Institute of Otolaryngology, Chinese PLA General Hospital, Beijing 100853, China. wht301@263.net
Tian
J
J
Yin
D
D
Jiang
S
S
Yang
W
W
Han
D
D
Yao
S
S
Shao
M
M
D000293:Adolescent; D000328:Adult; D001303:Auditory Cortex / Q000378:metabolism*; D005260:Female; D019788:Fluorodeoxyglucose F18; D005947:Glucose / Q000378:metabolism*; D006801:Humans; D008297:Male; D008875:Middle Aged; D019275:Radiopharmaceuticals; D014012:Tinnitus / Q000000981:diagnostic imaging / Q000378:metabolism*; D014055:Tomography, Emission-Computed
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; D005947:Glucose