Motor Threshold: A Possible Guide to Optimizing Stimulation Parameters for Motor Cortex Stimulation

Cyclization of Motor Cortex Stimulation for Neuropathic Pain: A Prospective, Randomized, Blinded Trial

“…Patients typically began to feel the ill effects of an ineffective cyclized setting approximately three days after the setting was changed. This was similar to the time course to observe beneficial effects when adjusting voltage as a PMT in our previous study .…”

“…Baseline data collection included age, sex, underlying pain condition, MCS devices used, location and duration of pain prior to MCS, quality of life (QoL) as measured by SF‐36 questionnaire, and current level of pain measured by the visual analog scale (VAS) (Table ). Voltage, selected as a PMT for each individual , pulse width, frequency (50 Hz), and active contacts remained unchanged.…”

“…Since the raw voltage required to produce pain relief in a given individual will vary based on electrode positioning, brain atrophy, and cortical excitability, in our previous study , we sought to convert the raw voltage into a more physiological parameter that measures the degree to which MCS affects the motor cortex. In brief, we calculated PMT as the raw voltage (required for pain relief) divided by the lowest voltage required to cause a motor contraction with all other variables held constant.…”

“…In brief, we calculated PMT as the raw voltage (required for pain relief) divided by the lowest voltage required to cause a motor contraction with all other variables held constant. We determined that an effective voltage for MCS for neuropathic pain can be predicted as a PMT and that minor deviations (±10%) could cause loss of pain control . Prior to entering this MCS cyclization study, patients’ effective MCS voltage as a PMT was determined in the clinic with the patient sitting upright and activating the muscle of interest.…”

“…There are no standardized programming protocols and the majority of programming strategies reported in literature rely on time‐consuming trial and error . Previously, our team has published an algorithm for MCS programing related to patient position and activity and selection of the optimal voltage as a percentage of motor threshold (PMT) . Cyclization of stimulation is another potentially important aspect of programming which needs to be systematically investigated.…”