Tailor-made notched music training–induced residual inhibition in subjective tinnitus: resting-state EEG spectral power ratio evidence

Objective: Residual inhibition (RI) is clinically useful but lacks objective markers. Tailor-made notched music training (TMNMT) is a non-invasive paradigm that may elicit RI. We evaluated whether resting-state EEG spectral power ratios (SPR) provide a convergent electrophysiological signature of TMNMT-induced RI. Methods: We retrospectively analyzed 29 adults with chronic subjective tinnitus who underwent a single 10-min TMNMT session. Resting-state EEG was recorded immediately before (pre-stim), during (during-stim), and after stimulation (post-stim). Power was estimated by Welch's method and summarized as band-limited SPR for delta (1-4 Hz), theta (4-8 Hz), alpha (8-13 Hz), and beta (13-30 Hz) relative to broadband power (1-30 Hz). Behavioral outcomes included visual analogue scales (VAS) for loudness/annoyance and RI intensity and duration. Repeated-measures non-parametric tests with false-discovery-rate (FDR) correction were the primary analyses; effect sizes were reported where applicable. Results: RI was observed in 20 of 29 patients (69%) following the routine TMNMT exposure. Across the cohort, VAS loudness/annoyance decreased within-session. SPR showed a frequency-specific shift characterized by increases in delta and theta power ratios and a reduction in alpha, with a non-significant downward trend in beta. Exploratory analyses suggested that higher baseline tinnitus severity (THI) was associated with greater VAS improvement and higher likelihood of RI positivity. Conclusion: The present retrospective analysis characterized behavioral and EEG spectral patterns observed during routine TMNMT exposure. We observed that TMNMT produced measurable tinnitus relief accompanied by frequency-specific SPR shifts. These findings collectively offer preliminary observational evidence and practical rationale for the potential clinical utility of TMNMT.