Abstracts

RATIONALE: Startle corresponds to an exaggerate motor response to an intense proprioceptive stimulation which projects to the central region and could induce a reflex seizure. Startle responses are triggered by unexpected and sudden stimuli associated to a specific electroclinical pattern followed by a reflex motor seizure in startle epilepsy. Reflex seizures of the central region represents a rare electroclinical entity in whom a somatosensitive or sensorial stimuli, without startle response, induce focal motor seizures. Neurophysiological and anatomical basis of those two reflex seizures are partially defined. We studied those two forms of central motor reflex seizures with or without startle response in order to investigate anatomo-functional networks by SISCOM (substraction of ictal and interictal SPECT images co-registrated to 3D MRI).
METHODS: All patients present symptomatic focal epilepsy, one case had somatosensitive reflex seizures and two had startle seizures. Investigations included video-EEG recordings, SISCOM (software: MEDIMAX, Biophysic Institut Strasbourg, France).
RESULTS: In all patients, SISCOM data showed an unilateral hyperperfusion of motor cortex (startle seizures), widespread to parietal cortex (somatosensitive reflex seizure) and subcortical structures (thalamus, basal ganglia). In startle seizures subcortical hyperperfusion was more evident on basal ganglia, brainstem, controlateral cerebellum.
CONCLUSIONS: SISCOM helps to define epileptic networks involved in extrapemporal epilepsies. Our results suggest that those two reflex epilepsies, (classified as different electroclinical entities) share partially the same neuroanatomical basis. However subcortical structures look to be more involved in startle seizures.