Rationale:
Epileptic events consistently elicited by specific stimuli are denominated reflex seizures. The trigger can be a sensory stimulus, visual being more common than tactile, proprioceptive or auditory. Less commonly, voluntary elementary movements or more complex cognitive tasks are the precipitating factors. We present an interesting case of focal seizures that are triggered by ambulation.
Method:
A 21 year-old male presented to our epilepsy monitoring unit for spells of decreased awareness, staring, head turning and involuntary arm movements, at times preceded by nausea. The spells lasted two minutes and were followed by confusion before the patient returned to his baseline cognition with no recollection of events. They occurred monthly up to multiple times a week. Walking frequently triggered these events. The patient was otherwise healthy and did not take medications. He had normal birth and development, without history of seizures. He reported a remote head trauma at age 4. His mother had epilepsy in childhood, transiently recurred as an adult after a head trauma. He did not use alcohol, tobacco products or recreational substances. His occupation was with physical labor in his family business.
Results:
Pre-admission consisted of normal routine electroencephalogram (EEG) and contrast enhanced magnetic ressonance imaging (MRI) brain revealed a left orbital hemangioma, but no brain pathology. The neurological exam was unremarkable on admission. The patient was kept off anticonvulsants for the five days of video-EEG monitoring. After two days without events, he was instructed to walk inside his room. Two events were then captured, both during ambulation. Clinically on both occasions there was behavioral arrest, head version to the right and clonic movements of the right arm. These lasted 50 and 90 seconds each, during which he did not answer questions appropriately. The patient was amnestic of what had occurred. Electrographically, both events started as background attenuation for three seconds followed by rhythmic right frontal theta discharges maximal at Fp2-F4 with a field at F8. Within seconds, it spread contralaterally becoming bihemispheric high voltage rhythmic delta discharges. Interictal EEG showed independent bihemispheric frontotemporal sharps and intermittent semi-rhythmic bifrontal slowing during drowsiness and sleep. Prior to discharge, the patient was started on Levetiracetam. Later a combination of Levetiracetam 1000 mg and Zonisamide 100 mg twice a day was effective in controlling his seizures.
Conclusion:
Movement-induced seizures are rare and share similar characteristics of kinesigenic dyskinesias. Potential described triggers for spells caused by ambulation include afferent proprioceptive stimuli or more complex cortical motor planning. The key clinical feature that differentiates these reflex seizures from a movement disorder is the altered awareness typical of epileptic events. In some patients the presentation is not always clear and both conditions respond to anticonvulsants. Therefore prolonged video-EEG monitoring is a vital tool for appropriate diagnosis and management, as well as for better counseling of these individuals. Identifying an epileptogenic zone is also helpful for future surgical planning. The role of the supplementary motor area was previously described a case of movement-induced seizures, and its resection resulted in resolution of epilepsy. Our patient has been well controlled with medications, but would benefit from more advanced work up if his seizures recur.
Funding:
:None.
FIGURES
Figure 1