Identifying Neuromodulation Targets for Disorders of Consciousness with Single-Pulse Electrical Stimulation Sima Mofakham PhD; Adam Fry; Susan M. Fiore MS, CCRC; Charles B. Mikell MD Stony Brook University Hospital

Introduction Evoked responses were compared to Both ACC and DLPFC stimulation ACC Stimulation (8 mA, 130 Hz, 4 Consciousness has been linked to consciousness, as measured using the caused broad evoked potentials, but seconds ending at time 0). functional connectivity across broad Coma Recovery Scale-Revised (CRS- ACC stimulation lead to bihemispheric cortical networks that enable rapid R). responses. Electrical stimulation of ACC modulates integration of information across EEG activity in PFC distant areas. Thus, potential targets Depth electrode placed across PFC and for neuromodulation should have ACC broad projections throughout the The amplitude of cortical-cortical cortex. Here, we used single-pulse evoked potential and its spatial spread stimulation of two potential targets, correlates with the level of prefrontal cortex and anterior consciousness cingulate cortex, to probe the connectivity of relevant cortical networks.

Results Conclusions Depth electrical recordings from ACC stimulation lead to broad evoked comatose patients exhibit very distinct potentials, which correlated with the A, B) The CCEP amplitude, here recorded features when compared to awake level of consciousness, a finding which at F3/C3, grows as the patient waking up patients. was less clearly seen with PFC Methods from TBI and deep midazolam sedation. C) stimulation. This suggests that ACC We enrolled four comatose traumatic Spatial spread of the stimulus correlates could be a potential neuromodulation brain injury patients with GCS<8 and ECoG distinguishes coma and with the CRS score when ACC (top row) or target for disorders of consciousness. with no major brain structural wakefulness PFC (bottom row) is stimulated. Contacts abnormalities. After informed consent with significant change from baseline were by a legally authorized representative, marked red. Learning Objectives we implanted a stereotactic ten- By the conclusion of this session, We have attempted to increase contact depth electrode spanning participants should be able to:1) arousal with electrical stimulation of anterior cingulate cortex (ACC) and Describe how electrical stimulation can ACC. Stimulation was associated with dorsolateral prefrontal cortex (DLPFC), be used to map corticocortical effective suppression of EEG activity in PFC. used clinically for seizure monitoring. connectivity 2) Identify the critical To probe frontal connectivity, we In the awake state, frequency profile criteria in selecting a potential administered repetitive single-pulse exhibit alpha and beta peaks for ACC and neuromodulation target stimulation to ACC and DLPFC (200 PFC, while in comatose patient power is µS, 1 Hz, 100 reps). We recorded mostly concentrated at low frequencies. evoked potentials on the depth electrode and scalp contacts.