Abstract Details

Title Subdural Recording of Generalized Photoepileptic Responses in a Patient with Focal Cortical Dysplasia

Topic Epilepsy

Presentation(s) P06 - (-)

Poster/Presentation
Number 174

Objective

Background BACKGROUND: Generalized PERs are rare in patients with focal epilepsy. We describe a young man with right frontocentral cortical dysplasia who also exhibited photosensitivity.

Design/Methods DESIGN/METHODS: Presurgical testing was reviewed with special attention to PERs on scalp and intracranial video EEG monitoring. Photic stimulation (PS) was performed daily at 1 to 30 Hz frequencies; responses classified as photic driving, photoparoxysmal or photoconvulsive responses. The spatiotemporal evolution of these responses on intracranial recordings were noted.

Results RESULTS: The 18 year old right-handed young man had medically refractory epilepsy since age three. On scalp video-EEG monitoring, he had generalized myoclonic seizures and complex partial seizures with focal tonic features, occurring in sleep with secondary generalization. PS elicited generalized PERs. Two right convexity subdural grids (SFG and GRD) were implanted. Frontal, parietooccipital (P, O) and interhemispheric (AIH, PIH) strips were placed to define relationship of the PERs with the epileptogenic lesion. Photic driving responses (PDRs) were elicited at 1-30 Hz frequencies at contacts O1-O3, more extensively at O4-6, P5-6 and SFG5/7 at frequencies of 12 Hz and higher. Focal spikes were induced first at P6-8 and O7, followed by SFG 5/7, AI2, lastly PIH 5-6. Generalized myoclonic activity (face, trunk, limbs) was activated with involvement of SFG 5/7 (central) electrodes. Generalized spikes, associated with generalized myoclonic activity, were only induced after onset of focal discharges in the visual cortices.

Conclusions CONCLUSIONS: The focal interictal epileptiform discharges were induced adjacent to regions reflecting the PDR, before spikes appeared more anteriorly in frontoparietal cortices. Myoclonic activity was associated with focal and generalized discharges involving the primary visual cortex. Despite limitations of the subdural electrode coverage, this study suggests a focal generation of photomyoclonic response.

Authors/Disclosures
Lakshmi Mukundan, MD (Cedar Park Neurology and Sleep Medicine) PRESENTER	No disclosure on file
Octavian V. Lie, MD	No disclosure on file
Linda Leary, MD (UT Health)	No disclosure on file
Alexander M. Papanastassiou	Alexander M. Papanastassiou has received intellectual property interests from a discovery or technology relating to health care.
Lola C. Morgan, MD (Department of Neurology)	Dr. Morgan has nothing to disclose.
Charles A. Szabo, MD, FAAN (UT Health San Antonio)	Dr. Szabo has received personal compensation in the range of $500-$4,999 for serving as a Consultant for LivaNova. Dr. Szabo has received personal compensation in the range of $500-$4,999 for serving as an officer or member of the Board of Directors for Epilepsy Foundation of Central and South Texas. Dr. Szabo has received personal compensation in the range of $0-$499 for serving as a Reviewer with NINDS.
Mitchell S. Elkind, MD, MS, FAAN	Dr. Elkind has received personal compensation for serving as an employee of American Heart Association. Dr. Elkind has received personal compensation in the range of $10,000-$49,999 for serving as a Consultant for Atria Academy.

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