Ictal pattern of EEG and muscular activation in symptomatic infantile spasms: a videopolygraphic and computer analysis.
OBJECTIVE
To investigate ictal muscular phenomena characterizing symptomatic infantile spasms (ISs) and their relation to ictal EEG.


METHODS
Four children with severe encephalopathy, neurologic impairment, and refractory ISs related to different dysplastic lesions, underwent videopolygraphic recordings collecting surface electromyogram (EMG) activity from several cranial and limb muscles to evaluate the pattern of muscular recruitment, duration, and side-to-side asymmetry of ISs. Acquired data were stored for off-line analysis by a computerized polygraphic system.


RESULTS
Spasms were characterized by a complex pattern of muscular activation. A constant or rostrocaudal propagation pattern was lacking in all patients. Intervals between the onset of EMG activity in different muscles in each spasm were very long: </=100-200 ms. Two patients, with hemispheric cortical dysplasia and agenesis of the corpus callosum, had asymmetric and asynchronous spasms in which the EMG onset of the muscles contralateral to the affected hemisphere constantly anticipated that of the ipsilateral ones. Backaveraging of EEG activity disclosed a high-amplitude EEG complex on the same side as the dysplastic lesion, preceding or succeeding the contralateral muscle activity onset. In the other two patients with diffuse cortical dysplasia, no EEG transient was related to EMG activity onset.


CONCLUSIONS
Despite clinical similarity between spasms in the same patient, our data demonstrate the complexity and heterogeneity of these motor phenomena. Our findings cannot be explained simply in terms of cortical or reticular generators like other motor phenomena such as cortical myoclonus or startle reflex.
Bisulli
Francesca
F
Department of Neurological Sciences, University of Bologna, Bellaria Hospital, Bologna, Italy. francesca.bisulli@neuro.unibo.it
Volpi
Lilia
L
Meletti
Stefano
S
Rubboli
Guido
G
Franzoni
Emilio
E
Moscano
Milena
M
d'Orsi
Giuseppe
G
Tassinari
Carlo Alberto
CA
D001925:Brain Damage, Chronic / Q000151:congenital* / Q000175:diagnosis / Q000503:physiopathology; D002540:Cerebral Cortex / Q000002:abnormalities / Q000503:physiopathology; D002675:Child, Preschool; D004292:Dominance, Cerebral / Q000502:physiology; D004569:Electroencephalography; D004576:Electromyography; D005260:Female; D006801:Humans; D007223:Infant; D007537:Isometric Contraction / Q000502:physiology*; D018482:Muscle, Skeletal / Q000294:innervation*; D011999:Recruitment, Neurophysiological / Q000502:physiology*; D012815:Signal Processing, Computer-Assisted; D013036:Spasms, Infantile / Q000175:diagnosis* / Q000503:physiopathology; D014741:Video Recording