Reduced auditory perception and brain response with quiet TMS coil

Area of Science:

• Neuroscience
• Biomedical Engineering
• Auditory Neuroscience

Background:

• Transcranial magnetic stimulation (TMS) coils produce loud noise, causing confounding auditory activation and potential hearing hazards.
• A novel quiet TMS double containment coil (qTMS-DCC) was developed to mitigate noise while maintaining stimulation efficacy.

Purpose of the Study:

• To compare the stimulation strength, perceived loudness, and electroencephalography (EEG) responses between the qTMS-DCC and a commercial TMS coil.
• To assess the efficacy of the qTMS-DCC in reducing auditory artifacts during TMS.

Main Methods:

• A within-subject study compared qTMS-DCC and MagVenture Cool-B65 in nine healthy volunteers.
• Resting motor thresholds (RMTs) were measured, and psychoacoustic titration matched loudness levels.
• Event-related potentials (ERPs) were recorded with coils on and off the scalp to differentiate auditory from electromagnetic stimulation.

Main Results:

• No significant difference in RMT was found between the qTMS-DCC and Cool-B65.
• qTMS-DCC was perceived as substantially quieter than Cool-B65.
• ERP analysis revealed similar brain stimulation but significantly reduced auditory activation (smaller P180 component) with qTMS-DCC.

Conclusions:

• The qTMS-DCC demonstrates comparable stimulation efficiency to conventional TMS coils.
• The qTMS-DCC significantly reduces perceived loudness and auditory-evoked potentials.
• This quiet TMS coil offers a promising alternative for reducing confounding auditory effects in TMS research and therapy.