Reflex Seizures Triggered from the Foot: Pathophysiological Mechanisms as Suggested by the Response to Surgical Procedures.
Abstract number :
2.282
Submission category :
Year :
2001
Submission ID :
493
Source :
www.aesnet.org
Presentation date :
12/1/2001 12:00:00 AM
Published date :
Dec 1, 2001, 06:00 AM
Authors :
A. Cukiert, MD, PhD, Neurosurgery, Hospital Brigadeiro, Sao Paulo, Brazil; E. Machado, MD, Neurosurgery, Hospital Brigadeiro, Sao Paulo, Brazil; J.A. Buratini, MD, Neurosurgery, Hospital Brigadeiro, Sao Paulo, Brazil; A. Sousa, MD, Neurosurgery, Hospital
RATIONALE: Reflex seizures triggered from the foot are rare and are often present in patients with widespread epileptogenic areas. This paper describes the response of such seizures to different surgical procedures.
METHODS: Two patients with foot[prime]s reflex seizures were studied. Patient I: MAR, a 32 years-old woman has had daily motor simple partial seizures starting in the left foot since the age of 8. The majority of the seizures were reflex and were triggered by touch in the left foot. MRI was normal. Somatosensitive evoked potentials (SSEP) were normal. Interictal EEG was normal as were ictal EEGs of the episodes restricted to the left foot. In fully developed hemibody[prime]s seizures a diffuse slowing over the right hemisphere was noted. She was submitted to subdural electrodes[ssquote] implantation with coverage of the entire fronto-parietal convexity and mesial regions. Ictal ECoG showed reflex seizures originating from both SMA and mid-mesial-parietal regions, simultaneously, sparing the rolandic gyri. SSEP obtained through the implanted electrodes were normal. She was submitted to SMA and mid-mesial parietal corticectomies, including the leg somatosensitive gyrus. Patient II: VR, a 7 years-old boy, has had seizures since the age of one. There were daily tonic, atonic, tonic-clonic, myoclonic, atypical absences and foot[prime]s reflex seizures. Atonic reflex seizures could be triggered by touch in either foot. MRI showed diffuse atrophy. Interictal EEG showed intense bilateral and synchronous spike and wave discharges. Ictal EEG showed bilateral and synchronous generalized discharges with no focal onset. He was submitted to complete callosal section.
RESULTS: Pathological examination in patient I showed moderate gliosis. She has been seizure-free since surgery (15 months). Post-operative left foot paresis was noted and lasted for 3 weeks. Patient II had 70% improvement in the frequency of non-reflex atonic, tonic, tonic-clonic and atypical absence seizures. Myoclonic and reflex atonic seizures remained unaltered. Post-operative interictal EEG showed interhemispheric disconnection.
CONCLUSIONS: The pathophysiology of foot[prime]s reflex seizures might include cortical mechanisms involving the mesio-parietal and SMA areas and is not influenced by the interhemispheric circuitry even when the reflex seizures are generalized (p.e., atonic) in nature. In same patients, widespread epileptogenic areas can be seen but the same phenomena can occur in patients with very restricted abnormal cortex.