title: Delineation of somatosensory finger areas using vibrotactile stimulation, an ECoG study.
abstract: BACKGROUND
  In surgical planning for epileptic focus resection, functional mapping of eloquent cortex is attained through direct electrical stimulation of the brain. This procedure is uncomfortable, can trigger seizures or nausea, and relies on subjective evaluation. We hypothesize that a method combining vibrotactile stimulation and statistical clustering may provide improved somatosensory mapping.
  
  
  METHODS
  Seven pediatric candidates for surgical resection underwent a task in which their fingers were independently stimulated using a custom designed finger pad, during electrocorticographic monitoring. A cluster-based statistical analysis was then performed to localize the elicited activity on the recording grids.
  
  
  RESULTS
  Mid-Gamma clusters (65-115 Hz) arose in areas consistent with anatomical predictions as well as clinical findings, with five subjects presenting a somatotopic organization of the fingers. This process allowed us to delineate finger representation even in patients who were sleeping, with strong interictal activity, or when electrical stimulation did not successfully locate eloquent areas.
  
  
  CONCLUSIONS
  We suggest that this scheme, relying on the endogenous neural response rather than exogenous electrical activation, could eventually be extended to map other sensory areas and provide a faster and more objective map to better anticipate outcomes of surgical resection.
authors.affiliation: Barrow Neurological Institute at Phoenix Children's Hospital Children's Neuroscience Research Phoenix Arizona ; School of Biological and Health Systems Engineering Arizona State University Tempe Arizona.
authors.forename: Rémy
authors.initials: R
authors.lastname: Wahnoun
authors.affiliation: Barrow Neurological Institute at Phoenix Children's Hospital Children's Neuroscience Research Phoenix Arizona.
authors.forename: Michelle
authors.initials: M
authors.lastname: Benson
authors.affiliation: School of Biological and Health Systems Engineering Arizona State University Tempe Arizona.
authors.forename: Stephen
authors.initials: S
authors.lastname: Helms-Tillery
authors.affiliation: Barrow Neurological Institute at Phoenix Children's Hospital Children's Neuroscience Research Phoenix Arizona ; School of Biological and Health Systems Engineering Arizona State University Tempe Arizona.
authors.forename: P David
authors.initials: PD
authors.lastname: Adelson
mesh_terms: D000293:Adolescent; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping / Q000379:methods*; D002540:Cerebral Cortex / Q000502:physiology; D002648:Child; D016000:Cluster Analysis; D004558:Electric Stimulation / Q000379:methods*; D000069280:Electrocorticography; D004569:Electroencephalography / Q000379:methods; D005260:Female; D005385:Fingers / Q000294:innervation*; D006801:Humans; D008297:Male; D010296:Parietal Lobe / Q000502:physiology; D013003:Somatosensory Cortex / Q000502:physiology; D055815:Young Adult
keywords: Electroencephalography; epilepsy; event‐related potentials; evoked potentials; fingers; somatosensory cortex