Icahn School of Medicine at Mount Sinai

A participant with severe upper-limb paralysis caused by amyotrophic lateral sclerosis (ALS) wore an endovascular stent-electrode array and a scalp EEG cap at the same time, in the same session, while attempting ankle flexion and extension. Both recordings changed markedly during attempted movement, but the stent array showed stronger per-channel motor modulation and was unaffected by skull attenuation. Scalp EEG was more susceptible to eye blinks and jaw-muscle activity, while the stent array picked up prominent cardiac signals. Neither method reliably distinguished left from right ankle movement, leaving spatial localization an open problem.

During removal of a right parafalcine meningioma, surgeons placed four Layer 7 μECoG arrays, 4,096 electrodes in total, on either side of the central sulcus and recorded somatosensory evoked potentials under 5 contralateral stimulation conditions. Using a 2 MΩ impedance cutoff, 3,739 channels were usable, a 91.3% yield; phase-reversal latencies were 19, 21, 25, 26 and 25 ms, consistent with the standard intraoperative mapping performed in the same operation. The researchers caution that the setup provides dense spatial sampling rather than submillimeter physiological resolution: measured responses were correlated across roughly 3–4 mm of cortex.

A workshop at the BCI Society Meeting 2025, run with the Implantable BCI Collaborative Community (iBCI-CC), took up how clinical outcome assessments (COAs) for pivotal BCI trials should be selected, developed and validated. Participants pointed to patient heterogeneity, the absence of widely validated COAs, and the difficulty of capturing outcomes that matter in home and daily-life settings. The discussion lays groundwork for the iBCI-CC Clinical Study Endpoints Workgroup to build a transparent process for identifying meaningful aspects of health and concepts of interest, in support of regulatory approval and reimbursement.

A paper in *Neurorehabilitation and Neural Repair* examines the outcome measures needed as implantable motor BCIs move from safety and feasibility studies toward regulatory approval, reimbursement and sustained clinical use. It calls for valid and reliable assessments that satisfy regulators and payers while reflecting activities that matter to people with severe motor impairment.