title: Visualizing the effects of rTMS in a patient sample: small N vs. group level analysis.
abstract: The use of transcranial magnetic stimulation (TMS) to assess changes in cortical excitability is a tool used with increased prevalence in healthy and impaired populations. One factor of concern with this technique is how to achieve adequate statistical power given constraints of a small number of subjects and variability in responses. This paper compares a single pulse excitability measure using traditional group-level statistics vs single subject analyses in a patient population of subjects with focal hand dystonia, pre and post repetitive TMS (rTMS). Results show significant differences in cortical excitability for 4/5 subjects using a split middle line analysis on plots of individual subject data. Group level statistics (ANOVA), however, did not detect any significant findings. The consideration of single subject statistics for TMS excitability measures may assist researchers in describing the variably of rTMS outcome measures.
authors.affiliation: Department of Physical Medicine and Rehabilitation, University of Minnesota, Minneapolis, Minnesota, United States of America. tjk@umn.edu
authors.forename: Teresa Jacobson
authors.initials: TJ
authors.lastname: Kimberley
authors.forename: Richard P
authors.initials: RP
authors.lastname: Di Fabio
mesh_terms: D000328:Adult; D018592:Cross-Over Studies; D003627:Data Interpretation, Statistical; D020821:Dystonic Disorders / Q000503:physiopathology*; D019054:Evoked Potentials, Motor / Q000502:physiology; D005260:Female; D006225:Hand / Q000503:physiopathology; D006230:Hand Injuries / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D009044:Motor Cortex / Q000502:physiology; D012107:Research Design; D050781:Transcranial Magnetic Stimulation / Q000379:methods*