Event-related fMRI of myoclonic jerks arising from dysplastic cortex.
BACKGROUND
Malformations of cortical development can cause epileptiform activity and myoclonic jerks, yet EEG correlates of jerks can be difficult to obtain.


METHODS
We studied a woman who had frequent episodes of persistent right-foot jerking since childhood. Ictal and interictal EEG had shown no localizing epileptiform activity. Functional imaging experiments were performed with concurrent video monitoring to document the timing of foot jerks. These studies mapped brain regions controlling voluntary right- and left-foot movements, and spontaneous right-foot jerks.


RESULTS
High-resolution structural MR imaging revealed a dysplastic gyrus extending anteriorly off the left central sulcus. Event-related analysis of spontaneous jerks revealed prominent activation of the left precentral gyrus (right-foot motor area), bilateral medial frontal regions (supplementary motor area), and the dysplastic gyrus. Hemodynamic response modeling to foot jerks revealed the hemodynamic response peaked earlier in the dysplastic cortex and SMA regions than in the foot area.


CONCLUSIONS
Event-related fMRI in a patient with spontaneous and induced epileptic foot jerks revealed brain regions active during jerks. The results of this analysis allowed us to tailor subsequent intracerebral recordings. Analysis of the timing of the hemodynamic response showed certain brain regions with an earlier rise in BOLD signal, suggesting a possible initiating role, or different hemodynamic response functions. Hemodynamic response timing should be considered carefully when interpreting event-related studies of epileptiform activity.
Archer
John S
JS
Brain Research Institute, Health, Austin, Victoria, Australia.
Waites
Anthony B
AB
Abbott
David F
DF
Federico
Paolo
P
Jackson
Graeme D
GD
D000328:Adult; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000002:abnormalities* / Q000503:physiopathology*; D004569:Electroencephalography / Q000706:statistics & numerical data*; D004831:Epilepsies, Myoclonic / Q000175:diagnosis* / Q000503:physiopathology; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D005528:Foot / Q000294:innervation / Q000503:physiopathology; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000706:statistics & numerical data*; D016343:Monitoring, Intraoperative / Q000706:statistics & numerical data; D009044:Motor Cortex / Q000503:physiopathology; D009069:Movement Disorders / Q000175:diagnosis / Q000503:physiopathology; D009434:Neural Pathways / Q000503:physiopathology; D010100:Oxygen / Q000097:blood; D014743:Videotape Recording
D010100:Oxygen