Perilesional pathological oscillatory activity in the magnetoencephalogram of patients with cortical brain lesions.
In the surrounding of focal ischemic brain lesions dysfunctional neuronal zones emerge often resulting in pathological oscillatory activity. Using whole-head magnetoencephalography we recorded brain activity during rest in 23 patients with ischemic cortical lesions to find out whether we can localise and characterise low-frequency oscillatory activity. We measured patients at different times after stroke and partly in a follow-up approach to determine the time course of slow-wave activity. Using the analysis tool Dynamic Imaging of Coherent Sources we computed tomographic maps of oscillatory power in the delta-band (0.5-3 Hz). Fifteen of 23 patients with cortical strokes showed delta-activity, which was localised in an area not more than 2 cm away from the lesion. We found this perilesional low-frequency activity in the acute as well as in the chronic stage of stroke. Follow-up measurements of individual patients revealed persistence of perilesional low-frequency activity for months and even years. No consistent relation between perilesional activity and clinical symptoms was observed. Our results indicate that perilesional delta activity is common after ischemic cortical stroke. However, the functional significance remains to be elucidated.
Butz
Markus
M
Department of Neurology, Heinrich-Heine-University, Moorenstrasse 5, 40225 Düsseldorf, Germany.
Gross
Joachim
J
Timmermann
Lars
L
Moll
Marek
M
Freund
Hans-Joachim
HJ
Witte
Otto W
OW
Schnitzler
Alfons
A
D000200:Action Potentials / Q000502:physiology; D000208:Acute Disease; D001683:Biological Clocks / Q000502:physiology*; D002545:Brain Ischemia / Q000175:diagnosis / Q000503:physiopathology*; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000473:pathology / Q000503:physiopathology*; D002544:Cerebral Infarction / Q000175:diagnosis / Q000503:physiopathology*; D002908:Chronic Disease; D003700:Delta Rhythm; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging; D015225:Magnetoencephalography; D008297:Male; D008875:Middle Aged; D009473:Neuronal Plasticity / Q000502:physiology; D011237:Predictive Value of Tests; D020127:Recovery of Function / Q000502:physiology; D013997:Time Factors