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 auditory activation and potential hearing damage.
• A new quiet TMS double containment coil (qTMS-DCC) was developed to mitigate noise while preserving 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 impact of reduced auditory noise on brain activity during TMS.

Main Methods:

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

Main Results:

• No significant difference in RMT was found between the qTMS-DCC and Cool-B65 coils.
• qTMS-DCC was perceived as substantially quieter, with 100% RMT qTMS-DCC loudness comparable to 34% RMT Cool-B65.
• Similar ERP waveforms and early-latency components indicated comparable brain stimulation, while qTMS-DCC showed reduced P180 auditory responses.

Conclusions:

• The qTMS-DCC offers equivalent stimulation efficiency to conventional TMS coils.
• qTMS-DCC significantly reduces perceived loudness and auditory-evoked potentials, minimizing confounding auditory activation.
• This technology allows for reduced auditory interference in TMS without compromising stimulation effectiveness.