Transcranial magnetic stimulation-evoked cortical inhibition: a consistent marker of attention-deficit/hyperactivity disorder scores in tourette syndrome.
BACKGROUND
Prior case-control studies using Transcranial Magnetic Stimulation (TMS) to probe the neural inhibitory circuitry of Attention Deficit Hyperactivity Disorder (ADHD), Tourette Syndrome (TS), and Obsessive Compulsive Disorder (OCD), have yielded conflicting results. Using regression analysis in TS patients with tics, ADHD, and/or OCD symptoms, all ranging from none to severe, we previously found that TMS-evoked short interval intracortical inhibition (SICI) correlated inversely with ADHD scores. We sought to validate this observation.


METHODS
We used regression to estimate the consistency of the association between ADHD symptom scores and TMS-evoked SICI at two separate visits in 28 children and adults with TS.


RESULTS
ADHD scores correlated significantly and consistently with SICI, particularly in patients not taking dopamine receptor blockers (r=.60 and r=.58). Hyperactivity, not inattention, scores accounted for ADHD-related variance in SICI.


CONCLUSIONS
SICI reliably reflects the severity of hyperactivity in children and adults with TS.
Gilbert
Donald L
DL
Division of Neurology, Cincinnati Children's Hospital Medical Center and University of Cincinnati, OH 45229-3039, USA. d.gilbert@cchmc.org
Sallee
Floyd R
FR
Zhang
Jie
J
Lipps
Tara D
TD
Wassermann
Eric M
EM
D000293:Adolescent; D000328:Adult; D001289:Attention Deficit Disorder with Hyperactivity / Q000175:diagnosis / Q000503:physiopathology* / Q000628:therapy; D002540:Cerebral Cortex / Q000187:drug effects / Q000503:physiopathology / Q000528:radiation effects; D002648:Child; D018492:Dopamine Antagonists / Q000627:therapeutic use; D004558:Electric Stimulation; D019054:Evoked Potentials, Motor / Q000187:drug effects / Q000528:radiation effects; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009433:Neural Inhibition / Q000502:physiology*; D009483:Neuropsychological Tests / Q000706:statistics & numerical data; D012044:Regression Analysis; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D018709:Statistics, Nonparametric; D005879:Tourette Syndrome / Q000175:diagnosis / Q000503:physiopathology* / Q000628:therapy; D050781:Transcranial Magnetic Stimulation
D018492:Dopamine Antagonists