title: Cortical stimulation parameters for functional mapping.
abstract: OBJECTIVE
  There is significant variation in how patients respond to cortical electrical stimulation. It has been hypothesized that individual demographic and pathologic factors, such as age, sex, disease duration, and MRI findings, may explain this discrepancy. The purpose of our study is to identify specific patient characteristics and their effect on cortical stimulation, and discover the extent of variation in behavioral responses that exists among patients with epilepsy.
  
  
  METHODS
  We retrospectively analyzed data from 92 patients with medically intractable epilepsy who had extra-operative cortical electrical stimulation. Mapping records were evaluated and information gathered about demographic data, as well as the thresholds of stimulation for motor, sensory, speech, and other responses; typical seizure behavior; and the induction of afterdischarges.
  
  
  RESULTS
  Ninety-two patient cortical stimulation mapping reports were analyzed. The average of the minimum thresholds for motor response was 4.15mA±2.67. The average of the minimum thresholds for sensory response was 3.50mA±2.15. The average of the minimum thresholds for speech response was 4.48mA±2.42. The average of the minimum thresholds for afterdischarge was 4.33mA±2.37. Most striking were the degree of variability and wide range of thresholds seen between patients and within the different regions of the same patient.
  
  
  CONCLUSIONS
  Wide ranges of thresholds exist for the different responses between patients and within different regions of the same patient. With multivariate analysis in these series, no clinical or demographic factors predicted physiological response or afterdischarge threshold levels.
authors.affiliation: Department of Neurosurgery, Duke University Hospital, DUMC Box 3807, Durham, NC 27710, United States. Electronic address: jacqulyn.corley@duke.edu.
authors.forename: Jacquelyn A
authors.initials: JA
authors.lastname: Corley
authors.affiliation: Department of Neurological Surgery, Rush University Medical Center, Chicago, IL 60612, United States.
authors.forename: Pouya
authors.initials: P
authors.lastname: Nazari
authors.affiliation: Department of Neurological Surgery, Carolinas Medical Center, Charlotte, NC 28203, United States.
authors.forename: Vincent J
authors.initials: VJ
authors.lastname: Rossi
authors.affiliation: Department of Neurological Surgery, Rush University Medical Center, Chicago, IL 60612, United States.
authors.forename: Nora C
authors.initials: NC
authors.lastname: Kim
authors.affiliation: College of Nursing, Rush University, Chicago, IL 60612, United States.
authors.forename: Louis F
authors.initials: LF
authors.lastname: Fogg
authors.affiliation: Department of Neurological Sciences, Rush University, Chicago, IL 60612, United States.
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Hoeppner
authors.affiliation: Department of Neurological Sciences, Rush University, Chicago, IL 60612, United States.
authors.forename: Travis R
authors.initials: TR
authors.lastname: Stoub
authors.affiliation: Department of Neurological Surgery, Rush University Medical Center, Chicago, IL 60612, United States.
authors.forename: Richard W
authors.initials: RW
authors.lastname: Byrne
mesh_terms: D000293:Adolescent; D000328:Adult; D001931:Brain Mapping; D058256:Brain Waves / Q000502:physiology*; D002540:Cerebral Cortex / Q000000981:diagnostic imaging / Q000503:physiopathology*; D002648:Child; D002675:Child, Preschool; D004558:Electric Stimulation / Q000379:methods*; D004569:Electroencephalography; D004827:Epilepsy / Q000000981:diagnostic imaging / Q000473:pathology* / Q000503:physiopathology / Q000601:surgery; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D059906:Neuroimaging; D012189:Retrospective Studies; D012684:Sensory Thresholds / Q000502:physiology; D055815:Young Adult
keywords: Afterdischarge; Cortex functional mapping; Perirolandic epilepsy; Sensory and motor cortex; Stimulation threshold