Are there distinctive EEG Signatures of tinnitus-related emotional distress? Evidence from spectral parameterization and source-level functional connectivity.

Subjective tinnitus is the perception of sound in the absence of an external acoustic source. This study used resting-state electroencephalography (EEG) to characterize abnormal neural oscillatory activity and electrophysiological features potentially associated with tinnitus-related emotional distress. Resting-state EEG data were collected from patients with tinnitus and healthy controls. Spectral parameterization was applied to separate aperiodic and periodic components and to extract the alpha center frequency. At the same time, source-level phase-locking value (PLV) was calculated to assess inter-regional functional connectivity. Patients with tinnitus exhibited a significantly higher aperiodic exponent than healthy controls, consistent with altered cortical excitation-inhibition (E/I) balance. In addition, the alpha peak frequency was significantly reduced in temporal regions, indicating slowing of local oscillatory activity within auditory cortical networks. Functional connectivity analysis revealed increased synchronization within and between auditory and parietal regions, accompanied by decreased connectivity involving the auditory regions, the anterior cingulate cortex, and prefrontal regions. These findings suggest that tinnitus is characterized by altered neural oscillatory activity and functional connectivity. These alterations may reflect abnormal auditory-network synchronization and altered cortical dynamics in tinnitus and may represent electrophysiological characteristics associated with tinnitus-related emotional distress that are not fully consistent with some findings previously reported in primary depressive disorders. These results further clarify the neurophysiological basis of tinnitus and may inform future neuromodulatory interventions.