Presurgical Motor Mapping With Transcranial Magnetic Stimulation (TMS)
Condition: Epilepsy
MeSH terms: Epilepsy
Study type: Interventional

Summary: 
      The aim of the study is to examine the degree of concordance between presurgical
      neuronavigation guided TMS (nTMS) and direct cortical stimulation (DCS) in identifying hand
      motor cortex in adults undergoing epilepsy surgery.

      Navigated transcranial magnet stimulation (nTMS), MagStim RapidStim2 Magnetic stimulation
      will be delivered to hand primary motor cortex, with positive and negative functional sites
      determined through surface electromyography (EMG).

      The study will involve patients ages 12-60 years, with planned neurosurgery involving
      implantation of intracranial subdural electrodes including over the precentral gyrus.

      Navigated transcranial magnet stimulation (nTMS), MagStim RapidStim2 Magnetic stimulation
      will be delivered to hand primary motor cortex, with positive and negative functional sites
      determined through surface electromyography (EMG).

      The primary outcome measure will be spatial correlation between topographic maps of hand
      motor representation obtained through nTMS compared to direct, extra-operative cortical
      stimulation performed as part of routine clinical care. A secondary outcome measure will be
      safety and tolerability of TMS in the epilepsy patients.
    

Detailed description: 
      This study will be an open-label feasibility study which applies nTMS to subjects with
      incoming epilepsy surgery and pre-surgical motor mapping. No study-related medication changes
      are expected -- participants will remain compliant with their regular anticonvulsant regimen
      throughout each study phase. All patients will have undergone a complete history and
      neurological exam as part of their routine clinical care at the New York University (NYU)
      Comprehensive Epilepsy Center.

      Fourteen (14) patients will undergo epilepsy surgery with expected subdural grid coverage
      over primary motor cortex. Potential subjects will be identified at the weekly
      multi-disciplinary epilepsy conference. Subjects must have a recent (<2 years) MRI scan, and
      registration of the TMS coil to the MRI scan via the Brainsight neuronavigation system will
      be utilized to guide TMS coil placement (Gugino et al 2001). When a presurgical fMRI
      (functional magnetic resonance imaging) is available which demonstrates the patient's hand
      knob, the fMRI will be used with the Brainsight neuronavigation system. Subjects will be
      recruited and consented during a presurgical clinical visit where the patient's primary
      epileptologist will introduce members of the research team.

      nTMS mapping

      Patients will receive a session of single-pulse TMS mapping of the motor area, at the
      outpatient TMS clinic at NYU Neurology Ambulatory Care Center, at 240 E 38th St 20th Floor
      prior their epilepsy surgery according to the following procedures:

        1. Determination of the motor threshold by (1) finding the most excitable region in the
           hand knob which elicits the strongest compound muscle action potential (CMAP) in the APB
           muscle; (2) finding the motor threshold by determining output stimulation intensity
           which generates peak to peak CMAP response above 50 mV (Millivolts) in 5/10 stimulation
           cycles (Rossini et al., 1994).

        2. Concurrent EMG will be measured with electrodes placed at APB (abductor policis brevis
           atrial premature beat), abductor digiti minimi, flexor carpiradialis muscles. Reference
           electrode will be placed at the ipsilateral elbow above the brachial biceps muscle.

        3. Mapping of the upper extremity. After determination of the MT (motor threshold), mapping
           of the UE(Upper Extremity) will be performed at 110% of the rMT (resting motor
           threshold). All positive and negative stimulation sites will be recorded and saved.
           Patients will be closely monitored during TMS stimulation. Each subject will have a
           complete neurological examined by a neurologist before and immediately after nTMS.
           Patients will also be provided a side effects questionnaire after TMS mapping. Patients
           will then be asked to keep a 7 day seizure diary after the nTMS session.

      After epilepsy surgery patients will receive the standard care for post-operative patients
      which including close monitoring in ICU overnight. Patients will be transferred to the floor
      for further clinical evaluation before discharge. Clinical outcome will be evaluated in the
      post-operative clinic visit within 1 month after discharge. The value of a clinical follow up
      is to evaluate for any discrepancy between nTMS and DCS, to determine which modality better
      predicts functional outcome. Any seizure recurrence or neurological deficit will be recorded
      at the follow-up clinical visit.

      The trial is designed to detect strength of spatial correlation between topographic maps of
      hand motor representation obtained through noninvasive nTMS compared to direct,
      extra-operative cortical stimulation obtained as part of usual clinical evaluation during
      epilepsy surgery, as measured by (a) average distance between positive motor mapping sites of
      DCS compared to nTMS and (b) degree of concordance between positive and negative motor
      mapping sites between DCS and nTMS, to generate positive and negative predictive values, and
      (c) average distance between positive motor functional sites of fMRI compared to nTMS.
    

Intervention name(s): The Magstim Rapid2,
Intervention type(s): Device
Intervention description(s): Transcranial Magnetic Stimulation, which is a microprocessor-controlled machine which delivers both single and repetitive transcranial magnetic stimulation (TMS).
single and repetitive transcranial magnetic stimulation (TMS). TMS will be applied as single pulses to determine motor evoked potentials (MEPs), there will be no modulation of cortical excitability.
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Diagnostic
Keywords: Transcranial magnet stimulation (nTMS); Brainsight Neuronavigation; Electromyography; EMG