Repetitive reaching training combined with transcranial Random Noise Stimulation in stroke survivors with chronic and severe arm paresis is feasible: a pilot, triple-blind, randomised case series.

Only four participants were studied, each treated as a single case, so the study cannot show whether active transcranial random noise stimulation works better than sham. The study was designed for feasibility, not efficacy, and the clinical results were reported as individual changes rather than group comparisons. All participants received reaching training and outcome-triggered electrical stimulation in addition to active or sham transcranial random noise stimulation, so any improvement cannot be attributed to the stimulation alone. Stimulation timing was not precisely locked to each movement attempt; onset was not yoked to electromyography and offset was fixed at 5 seconds. Participants were restricted to 6 months to 5 years after first stroke and severe upper limb impairment, so the findings may not apply to milder impairment or earlier recovery. Medications that could affect cortical excitability or neural plasticity were excluded, which may limit generalisability to patients taking such medications. Some participants had aphasia, and carer interviews were used, so subjective experiences may be influenced by proxy report. The sample was too small to examine relationships between corticospinal tract integrity and recovery.

Do not conclude that transcranial random noise stimulation improves arm recovery. This pilot gave active or sham transcranial random noise stimulation together with reaching training and outcome-triggered electrical stimulation, included only four participants, and did not show benefit of active stimulation over sham.