NCT06646302

Residual Inhibition of 40 Hz Burst Sound in Tinnitus Patients

Neural and Clinical Effects of 40 Hz Burst Stimulation in Tinnitus: a Four-phase Self-controlled Study

• Status: Completed
• Phase: N/A
• Study type: Interventional
• Enrollment: 265 (actual)
• Sponsor: Eye & ENT Hospital of Fudan University · Academic / Other
• Sex: All
• Age: 18 Years – 70 Years
• Healthy volunteers: Not accepted

Summary

Tinnitus affects 10-15% of adults and is frequently associated with impaired quality of life, anxiety, and sleep disturbance. Conventional sound therapies based on continuous masking provide inconsistent and short-lived relief, and the neural mechanisms underlying residual inhibition (RI) remain unclear. This study aims to determine whether 40 Hz burst stimulation with high-frequency carriers can achieve longer-lasting RI than continuous sound, and to explore its underlying neural mechanisms using EEG.

Detailed description

Residual inhibition (RI) refers to the temporary reduction or disappearance of tinnitus following sound stimulation and provides an important clue for identifying patients who may benefit from acoustic therapy. However, the effects of different sound stimulation strategies on RI remain poorly understood. This study evaluates whether 40 Hz burst-modulated sound achieves stronger and longer RI compared with conventional continuous stimulation. The trial follows a four-phase design: Phase 1: Exploratory testing of burst versus continuous tones at different frequencies. Phase 2: Large-scale validation in 265 patients. Phase 3: Development of a personalized stimulation protocol using adaptive spectral optimization. Phase 4: EEG investigation of neural mechanisms, focusing on gamma oscillations and functional connectivity changes. The primary outcomes are the strength and duration of tinnitus suppression. Secondary outcomes include EEG markers such as γ-band power spectral density and phase-locking value. By combining behavioral and neurophysiological measures, this study aims to establish 40 Hz burst stimulation as a novel rhythm-based sound therapy and to provide mechanistic insights that may enable more effective, personalized tinnitus management.

Conditions

• Tinnitus

Interventions

Type	Name	Description
OTHER	Personalized 40 Hz Broadband Stimulation	Broadband acoustic stimulus (125 Hz-12 kHz) amplitude-modulated at 40 Hz with a 50% duty cycle. A polynomial regression and FFT-based algorithm applies individualized frequency weighting, combining population data (70%) and patient-specific responses (30%). Delivered for 60 seconds at 10 dB above the individual minimum masking level (MML).
OTHER	40 Hz Pure Tone Stimulation	Pure tone stimulus at the optimized frequency (matched to tinnitus characteristics or high-frequency carrier), amplitude-modulated at 40 Hz with a 50% duty cycle. Delivered for 60 seconds at 10 dB above MML.
OTHER	Continuous Broadband Noise	Continuous broadband noise spanning 125 Hz-12 kHz without 40 Hz modulation. Delivered for 60 seconds at 10 dB above MML as an active control condition.

Timeline

• Start date: 2024-10-28
• Primary completion: 2025-07-18
• Completion: 2025-07-18
• First posted: 2024-10-17
• Last updated: 2025-09-11

Locations

1 site across 1 country: China