Brain Stimul. 2025 Jun 6:S1935-861X(25)00255-4. doi: 10.1016/j.brs.2025.06.004. Online ahead of print.
ABSTRACT
BACKGROUND: Essential tremor (ET), the most common movement disorder in adults, presents with involuntary shaking of the upper extremities during postural hold and kinetic tasks linked to dysfunction in the cerebello-thalamo-cortical network. Recently, transcutaneous afferent patterned stimulation (TAPS), applied through a wrist-worn device, has emerged as a non-invasive treatment for medication-refractory ET. However, its mechanism remains unclear.
OBJECTIVE: We hypothesize that TAPS reduces tremors through modulation of the VIM thalamus in the cerebello-thalamo-cortical network.
METHODS: Employing refractory pure ET patients seeking VIM deep brain stimulation (DBS), we quantified clinical tremor improvement following TAPS treatment in a pre-operative setting, followed by intra-operative, microelectrode recording of the contralateral thalamus with concurrent TAPS treatment on and off.
RESULTS: After one preoperative session, TAPS significantly reduces upper limb tremor average (0.61, p=0.002), with an asymmetric effect favoring the treated limb (p=0.047) and the greatest improvement tending to kinetic tremor (R2=0.943, p=0.002). The magnitude of TAPS-related tremor reduction demonstrates a positive correlation with the modulation of alpha (R2=0.213, p<0.001) and beta band LFPs (R2=0.255, p<0.001) in the VIM. TAPS also suppressed spiking activity in the VIM (R2=0.104, p=0.029), though it was uncorrelated with the degree of tremor reduction. Of note, TAPS-related modulation of LFPs and spiking activity was greatest near the optimal placement location for the DBS lead in treating ET (R2=0.122, p=0.006).
CONCLUSION: In sum, TAPS likely reduces tremor in ET by modulating the VIM and connected nodes in the cerebello-thalamo-cortical pathway.medRxiv Preprint: https://doi.org/10.1101/2024.12.02.24317799.
PMID:40484122 | DOI:10.1016/j.brs.2025.06.004