Authors :
Presenting Author: Oman Magana-Tellez, PhD – UTHealth Houston
Jowah Gorbachev, MD – UTHealth Houston
Blanca Talavera, MD – UTHealth Houston
Vladimir Vashin, BS – UTHealth Houston
Chaitanya Ganne, MD, PhD – UTHealth Houston
Johnson Hampson, MBBE – UTHealth Houston
Sandhya Rani, PhD – UTHealth Houston
Nitin Tandon, MD – McGovern Medical School, University of Texas Health Science Center at Houston
Sandipan Pati, MBBS – UT Health Houston
Samden Lhatoo, MD – UTHealth Houston
Nuria Lacuey, MD, PhD – UTHealth Houston
Rationale:
Video-electroencephalography (EEG) monitored sudden unexpected death in epilepsy (SUDEP) deaths have established the role of central apnea in the fatal cascade of cardiorespiratory phenomena terminating in death. Electrical stimulation of cortico-limbic regions has confirmed their involvement in respiration, however, the participation of thalamic nuclei in these processes is not well understood. In this study, we aimed to investigate thalamic nuclei involved in respiration by analyzing respiratory changes induced by stimulation of the anterior thalamic nucleus (ANT), pulvinar (PUL), centromedian nucleus (CM), ventral posterolateral nucleus (VPL), ventral anterior nucleus (VA), and ventral lateral nucleus (VL). We used visual and quantitative analysis of breathing rate (BR), tidal volume (TV), and minute ventilation (MV) to corroborate our hypothesis that the thalamic nuclei modulate breathing rate, depth, and volume.
Methods:
We analyzed 11 patients with medically refractory epilepsy. These were patients undergoing stereoelectroencephalography (SEEG) and those with chronically implanted electrodes (deep brain stimulation) in the thalamus who were undergoing EEG evaluation. Bedside bipolar, biphasic electrical stimulation was performed with cardiorespiratory data, EEG, and SEEG, end-tidal carbon dioxide (ETCO2), and airflow obtained during the session. BR, MV, and TV were calculated for each stimulation and pre-stimulation baseline trial using the Breathmetrics toolbox. We studied stimulation-induced changes in the respiration parameters as a percentage change from preceding interstimulus baseline windows. Individual and group level analyses were performed, as well as a linear mixed-effects model for the relationship between MV and the blood gasesResults:
We analyzed a total of 319 stimulation trials with a total of 50/74 (67.57%) electrode contacts being stimulated. ANT stimulation was associated with significant changes in respiration, including tidal volume (0.0001) and minute ventilation (0.0001). Unilateral ANT stimulation induced a decrease in minute ventilation (p = 0.0001), tidal volume (p = 0.0170), and breathing rate (p = 0.03). In contrast, bilateral stimulation induced an increase in tidal volume (p = 0.0073) and minute ventilation (p = 0.0059). MV increases were associated with an increase in SpO2 (p < 0.001) and a decrease in ETCO2 (p < 0.001), while MV decreases were associated with a decrease in SpO2 (p < 0.001) and an increase in ETCO2 (p < 0.001).