Abstracts

RATIONALE: Two fold purposes: 1) To quantify and analyze repetitive grasping, which we observed during the complex motor sequences, characterizing [dsquote]hypermotor[dsquote] (Luders et al., 1998), [dsquote]frontal[dsquote] (Williamson et al., 1985) seizures. 2) To ascertain whether grasping can occur in seizures types other than the [dsquote]hypermotor[dsquote] [dsquote]frontal[dsquote] one.
METHODS: 30 [dsquote]hypermotor[dsquote] seizures, lasting more than 30 seconds, were video and polygraphically recorded in 12 patients. Off-line frame by frame video-analysis were performed. Frequency, side and site of grasping and latency from seizure onset were evaluated. Occurrence of grasping was also analyzed in a control group of 41 consecutive patients, who presented 193 video-polygraphically recorded seizures, without the [dsquote]hypermotor[dsquote] manifestations, according to Luders (1998) semeiological definition.
RESULTS: 1) Grasping was observed in 29 hypermotor seizures out of 30 (96,66%); the total number of Grasping phenomena, recorded in all seizures, was 117 (mean value of 6,7 repetitive events per seizure), with a mean latency of 3 seconds from clinical onset. Grasping was mainly directed to bed equipment, genitals, thigh, gluteus; it often appeared to have function of steadying point for [dsquote]pedaling-bicycling-rocking[dsquote] movements. During the same seizure, both arms could perform the grasping, that was generally preceded by reaching and followed by holding or pulling, as in case of voluntary physiological prehension (Rizzolatti et al., 1993).
2) Grasping was not observed in 193 seizures without hypermotor behaviors (control group).
We can conclude that repetitive grasping is quite specifically related to the complex motor manifestations characterizing the [dsquote]hypermotor[dsquote] seizure.
CONCLUSIONS: Our data shows that forced prehension (Grasping) is a frequent and, in our experience, specific manifestation in [dsquote]frontal[dsquote] [dsquote]hypermotor[dsquote] seizures. Grasping can be considered as an innate motor behavior (Grillner and Wallen, 1985), physiologically present in newborn and lately occurring in pathological conditions related to disfunction of frontal lobe. According to Denny Brown (1960), [dsquote]instinctive tactile grasping and placing are related to mesial frontal lesion . and disturb the balance in favor of exaggeration of grasping[dsquote]. Therefore, the seizure event can trigger hypermotor clinical manifestations as well as interfere with inhibitory frontal function leading to a release of grasping innate behavior.