Authors :
Presenting Author: Claudia Vallin, DO – Cleveland Clinic, Florida
Debolina Ghosh, MD – Cleveland Clinic
Imad Najm, MD – Cleveland Clinic
Paul Marasco, PhD – Cleveland Clinic
Ahsan Moosa Naduvil Valappil, MD, FAES – Cleveland Clinic
Rationale:
Body ownership is the feeling that one’s limbs and body parts belong to them. The sense of ownership arises from multisensory brain networks that compare internal expectations with sensory experiences. An inferential understanding of the complex relationships between parietal-focused brain areas involved with ownership is emerging through neuroimaging and lesion studies in humans, and neurophysiological studies in animals. However, the real-time function of the specific human brain areas involved in these processes is unknown. We were able to study a real time temporary dysfunction of the body ownership network during a seizure in a patient undergoing stereoelectroencephalography (SEEG) with dense right parietal implantation.
Methods:
We describe a 38-year-old right-handed woman with drug-resistant focal epilepsy. Her habitual seizures had psychic aura followed by oral automatisms or generalized motor seizures. Complications from a prior intracranial EEG evaluation with subdural grids resulted in right frontoparietal encephalomalacia and mild left hand numbness and weakness. She underwent right hemispheric SEEG to localize the epileptogenic zone and determine involvement of the right frontoparietal gliosis. An atypical spontaneous seizure with a unique seizure semiology of ictal disembodiment of the left upper extremity that slowly evolved over 10 minutes is the main focus of this report.
Results:
The seizure evolved in three phases: an initial period with no clinical signs, a second phase with left arm ataxia, and a third with loss of ownership of the left arm. The patient was asleep at seizure onset with no clinical signs for the first 4 minutes, followed by feeling 'weird in the head.’ Subsequently, when asked to raise both arms above the head, the left arm was ataxic and dropped behind her head, out of her view. In the final phase, she was unable to locate or move her left arm, which was out of sight. Expecting it to be at her side, she exclaimed loudly, 'Where is it? Where the hell is my hand?' while actively searching for it with her right hand. When the left arm was brought to her view passively by the bedside caregiver, she appeared frightened and reported that ‘it is not there’ while looking at it and feeling it. Ictal onset and organization also showed 3 phases with onset in the right supramarginal gyrus with initial spread to the dorsal post-central gyrus, later evolving to parietal operculum, precentral gyrus and lateral post-central gyrus in the second phase. The third phase with disembodiment occurred with involvement of the precuneus, superior parietal lobule, intraparietal sulcus, and angular gyrus.
Conclusions:
This seizure evolution captured the patient’s actions, reactions, exclamations, and descriptive responses coupled to electrophysiological activity as the seizure progressed through brain regions known to be functionally intertwined in multisensory integration. The overt sense of this patient’s left upper limb ownership was specifically interrupted when the seizure organized in the right intraparietal sulcus/angular gyrus and precuneus/superior parietal lobule.
Funding: None