Abstracts

Rationale: Out-of-body experience (OBE) is frequently described as a feature of near death experience in post cardiac arrest survivors. Similar phenomenon has been reported in patients with epilepsy, and migraine. Rare reports of OBE with cortical stimulation have been documented. Most of these reports indicate involvement of the non dominant lateral temporo-parietal junction. We report a patient with OBE during extra-operative cortical stimulation of the right ('non-dominant')precuneus. Precuneus has not been recognized previously as a potential generator of OBE. Methods: A 35-year-old, right handed woman, had intractable epilepsy from the age of 12 years. Non invasive evaluation suggested right frontal lobe epilepsy. She underwent intracranial EEG monitoring using subdural grids in the fronto-temporal and medial parietal regions. Seizure onset was localized to the right superior and middle frontal gyrus. She became seizure free following resection of right superior and middle frontal gyri, she remained seizure free at 2-year-follow up. Cortical stimulation was performed pre-operatively to identify eloquent areas in the frontal and medial fronto-parietal regions. Results: On stimulation of the anterior part of right precuneus, at 6 mA, patient reported subjective out-of-body experience. She reported: I just feel the same thing again I know everybody is here but I don t feel like I am in the room I feel like I am watching down from above I feel very detached I feel disconnected from every one in the room ". The same subjective experience was reproduced with repeat stimulation, performed an hour later. OBE was not part of her seizure semiology. Out-of-body experience following cortical stimulation of right (non dominant)lateral temporo-parietal junction has been well documented. There are no previous reports of OBE elicited from precuneus. In one previous report of PET study performed during OBE elicited by cortical stimulation of right temporo-parietal junction, simultaneous activation of the inferior parietal lobule and ipsilateral precuneus was noted. Findings in our patient also support a role for precuneus in the generation of OBE. Conclusions: We report out-of-body experience elicited by electrical stimulation of right anterior precuneus. This finding is at variance from earlier observations of out-of-body experience with stimulation of non dominant lateral temporo-parietal junction. Connections between the non dominant temporo-parietal junction and ipsilateral precuneus may be important for the generation of out of body experience.