Kilohertz Transcranial Magnetic Perturbation (kTMP) for Upper Extremity Motor Recovery After Stroke: A Nonrandomized Pilot Trial
- 1Department of Neurology, University of California San Francisco
Abstract
Structured AbstractO_ST_ABSImportanceC_ST_ABSUpper extremity impairment is a leading cause of post-stroke disability, yet clinically approved neuromodulation therapies are currently limited by the risks and costs of surgical implantation. There is an unmet need for non-invasive brain stimulation.
ObjectiveTo evaluate the feasibility, safety, and preliminary clinical efficacy of a novel form of non-invasive brain stimulation, kilohertz transcranial magnetic perturbation (kTMP), for upper limb motor recovery after stroke.
DesignA single-center, open-label trial was conducted between September 2025 and April 2026 and comprised a 4-week standard-of-care baseline period, 4 weeks of active treatment with kTMP combined with motor training, and a 4-week follow-up.
SettingAcademic research center.
ParticipantsSeven individuals with chronic stroke and upper extremity motor deficits. Intervention: Four weeks of kTMP (3 sessions/week), a brain stimulation approach using magnetic induction to generate subthreshold electric fields, paired with motor tasks.
Main OutcomesChange in Fugl-Meyer Assessment for Upper Extremity (FMA-UE) scores across study periods (standard-of-care baseline, active treatment, follow up). Secondary outcomes included measures of movement smoothness (Spectral Arc Length, SPARC) and fragmentation (mean velocity peak count), and intervention tolerability ratings.
ResultsAcross 7 participants (mean [SD] age, 57.4 [8.7] years; 4 males; mean [SD] time poststroke, 3.5 [2.1] years). No device-related adverse events occurred, and the intervention was well-tolerated (participants rated sensation intensity at an average of less than 0.5 on a 0-10 scale). FMA-UE scores remained stable during the baseline period (mean change, +0.14 points; 95% CI, -1.21 to 1.50; adjusted P =.98), increased significantly following the kTMP-intervention (mean change, +7.00 points; 95% CI, 5.31 to 8.69; adjusted P =.047), and were sustained at the 4-week follow-up (mean change, -1.33 points; 95% CI, -2.42 to -0.25; adjusted P =.13). Movement smoothness improved significantly within 1 week of kTMP onset (mean change, 1.48 points; 95% CI, 0.49-2.47; adjusted P =.03); movement fragmentation showed a similar but nonsignificant trend.
Conclusions and RelevanceThis pilot trial provides preliminary evidence that kTMP combined with motor tasks is safe, feasible, and may support upper extremity recovery. These pilot data warrant large, randomized controlled trials to evaluate efficacy in support of poststroke motor recovery.
Trial Registration: ClinicalTrials.gov IdentifierNCT06317194
Key PointsO_ST_ABSQuestionC_ST_ABSIs kilohertz transcranial magnetic perturbation (kTMP) a safe, feasible, and effective non-invasive intervention for improving upper extremity motor recovery in chronic stroke?
FindingsIn this single-center, open-label pilot trial of 7 participants with chronic stroke, upper extremity motor impairment (FMA-UE) remained stable during a 4-week baseline period and significantly improved (mean change, +7.0 points) following 4 weeks of active kTMP treatment combined with motor tasks, with gains sustained at 4-week follow-up. No device-related adverse events occurred.
MeaningThese preliminary findings suggest that kTMP is safe and feasible and may support upper extremity motor recovery after stroke, warranting further evaluation.
Related
- Mechanisms of transcranial magnetic brain stimulation
- Accelerated transcranial magnetic stimulation for depression: optimizing dose, spacing, targeting, and durability rather than speed alone
- Robot-Assisted Transcranial Magnetic Stimulation Guided by Cortical Topography
- Characterizing the mechanisms that determine the strength of the subjectively perceived discomfort during transcranial magnetic stimulation
- Physics-informed neural operators for rapid electric field prediction in transcranial magnetic stimulation of healthy and tumor subjects
BibTeX
@misc{merrick2026kilohertz,
title = {{Kilohertz Transcranial Magnetic Perturbation (kTMP) for Upper Extremity Motor Recovery After Stroke: A Nonrandomized Pilot Trial}},
author = {C. M. Merrick and F. Dai and S. Singh and I. O'Kidhain and P. Reber and C. Luu and A. V. Peterchev and D. Sheltraw and R. B. Ivry and L. Labruna and K. Ganguly},
howpublished = {medRxiv},
year = {2026},
month = oct,
doi = {10.64898/2026.10.05.26364594},
url = {https://www.medrxiv.org/content/10.64898/2026.10.05.26364594v1},
note = {CC BY},
}
RIS
TY - UNPB
TI - Kilohertz Transcranial Magnetic Perturbation (kTMP) for Upper Extremity Motor Recovery After Stroke: A Nonrandomized Pilot Trial
AU - C. M. Merrick
AU - F. Dai
AU - S. Singh
AU - I. O'Kidhain
AU - P. Reber
AU - C. Luu
AU - A. V. Peterchev
AU - D. Sheltraw
AU - R. B. Ivry
AU - L. Labruna
AU - K. Ganguly
PY - 2026
DA - 2026/10/05
PB - medRxiv
DO - 10.64898/2026.10.05.26364594
UR - https://www.medrxiv.org/content/10.64898/2026.10.05.26364594v1
AB - Structured AbstractO_ST_ABSImportanceC_ST_ABSUpper extremity impairment is a leading cause of post-stroke disability, yet clinically approved neuromodulation therapies are currently limited by the risks and costs of surgical implantation. There is an unmet need for non-invasive brain stimulation. ObjectiveTo evaluate the feasibility, safety, and preliminary clinical efficacy of a novel form of non-invasive brain stimulation, kilohertz transcranial magnetic perturbation (kTMP), for upper limb motor recovery after stroke. DesignA single-center, open-label trial was conducted between September 2025 and April 2026 and comprised a 4-week standard-of-care baseline period, 4 weeks of active treatment with kTMP combined with motor training, and a 4-week follow-up. SettingAcademic research center. ParticipantsSeven individuals with chronic stroke and upper extremity motor deficits. Intervention: Four weeks of kTMP (3 sessions/week), a brain stimulation approach using magnetic induction to generate subthreshold electric fields, paired with motor tasks. Main OutcomesChange in Fugl-Meyer Assessment for Upper Extremity (FMA-UE) scores across study periods (standard-of-care baseline, active treatment, follow up). Secondary outcomes included measures of movement smoothness (Spectral Arc Length, SPARC) and fragmentation (mean velocity peak count), and intervention tolerability ratings. ResultsAcross 7 participants (mean [SD] age, 57.4 [8.7] years; 4 males; mean [SD] time poststroke, 3.5 [2.1] years). No device-related adverse events occurred, and the intervention was well-tolerated (participants rated sensation intensity at an average of less than 0.5 on a 0-10 scale). FMA-UE scores remained stable during the baseline period (mean change, +0.14 points; 95% CI, -1.21 to 1.50; adjusted P =.98), increased significantly following the kTMP-intervention (mean change, +7.00 points; 95% CI, 5.31 to 8.69; adjusted P =.047), and were sustained at the 4-week follow-up (mean change, -1.33 points; 95% CI, -2.42 to -0.25; adjusted P =.13). Movement smoothness improved significantly within 1 week of kTMP onset (mean change, 1.48 points; 95% CI, 0.49-2.47; adjusted P =.03); movement fragmentation showed a similar but nonsignificant trend. Conclusions and RelevanceThis pilot trial provides preliminary evidence that kTMP combined with motor tasks is safe, feasible, and may support upper extremity recovery. These pilot data warrant large, randomized controlled trials to evaluate efficacy in support of poststroke motor recovery. Trial Registration: ClinicalTrials.gov IdentifierNCT06317194 Key PointsO_ST_ABSQuestionC_ST_ABSIs kilohertz transcranial magnetic perturbation (kTMP) a safe, feasible, and effective non-invasive intervention for improving upper extremity motor recovery in chronic stroke? FindingsIn this single-center, open-label pilot trial of 7 participants with chronic stroke, upper extremity motor impairment (FMA-UE) remained stable during a 4-week baseline period and significantly improved (mean change, +7.0 points) following 4 weeks of active kTMP treatment combined with motor tasks, with gains sustained at 4-week follow-up. No device-related adverse events occurred. MeaningThese preliminary findings suggest that kTMP is safe and feasible and may support upper extremity motor recovery after stroke, warranting further evaluation.
ER -