Focal Metabolic Activation in the Predominant Left Auditory Cortex in Patients Suffering from Tinnitus: A PET Study with [<sup>18</sup>F]Deoxyglucose

TLDR

Objective evidence links tinnitus to left auditory cortex activation, but interpretation is limited by scarce combined imaging and acoustic data. The study used FDG‑PET to measure metabolic activity in 11 chronic tinnitus patients, including repeated scans of one patient across varying symptom severity. Nine of eleven patients showed significantly higher left primary auditory cortex metabolism compared to controls, with activity correlating with tinnitus severity and absent in a patient without subjective symptoms.

Abstract

Eleven patients suffering from chronic disabling tinnitus underwent an FDG-PET study (positron emission tomography with [18F]deoxyglucose). Nine tinnitus patients revealed a significantly increased metabolic activity in the left, 1 in the right primary auditory cortex (PAC, Brodmann area 41). These results were statistically significant when compared to 14 healthy control individuals without tinnitus. A negative result was obtained from a chronic tinnitus patient but who had no subjective complaints during the period of PET investigation. One patient was first investigated during a disabling tinnitus period, later during a period with tinnitus relief and again when suffering from severe tinnitus. The metabolic activity of his left PAC was in good accordance with the subjective degree of tinnitus complaints present during each PET investigation. Although for the first time these results give objective evidence of tinnitus sensation and localization, they are difficult to interpret because of the limited research data available that combine functional brain imaging and acoustic stimuli.