Relevance of interictal epileptiform discharges and sleep related oscillatory activity in the human anterior thalamus for deep brain stimulation therapy
Abstract number :
2.4
Submission category :
3. Neurophysiology / 3E. Brain Stimulation
Year :
2021
Submission ID :
1886497
Source :
www.aesnet.org
Presentation date :
12/5/2021 12:00:00 PM
Published date :
Nov 22, 2021, 06:56 AM
Authors :
Daniel Fabo, MD PhD - National Institute of Mental Health, Neurology and Neurosurgery; Zsofia Jordan, MD - National Institute of Mental Health, Neurology and Neurosurgery, Budapest, Hungary; Barbora Deutschova, MD - St. Anne's University Hospital, Brno, Czech Republic; Orsolya Szalardy, MSC - Semmelweis University, Budapest, Hungary; Nora Peto, MD - National Institute of Mental Health, Neurology and Neurosurgery, Budapest, Hungary; Robert Bodizs, PhD - Semmelweis University, Budapest, Hungary; Ivan Rektor, MD PhD - St. Anne's University Hospital, Brno, Czech Republic; Lorand Eross, MD PhD - National Institute of Mental Health, Neurology and Neurosurgery, Budapest, Hungary
Rationale: Anterior thalamus (ANT) deep-brain stimulation (DBS) is an approved neuromodulation therapy for drug resistant epilepsy. The effectivity is based on double-blind clinical studies showing that the lesioning or high frequency stimulation of the ANT can reduce or alleviate epileptic seizures. Neuronal markers for good therapy outcome are largely unknown. In this study we aimed to record local field potentials in the ANT and correlate the finding with therapy response.
Methods: We implanted 22 therapy resistant epilepsy patients with bilateral ANT-DBS lead system. The lead was targeted stereotactically. After lead implantation an extension cable was attached and externalized, and the patients were monitored for two consecutive nights. Additional overnight scalp EEG data was collected 1 month after implantation at stimulator initial setup, and polysomnography performed between post implantation 1 and 3 years. We analysed the non-stimulated intrathalamic epileptiform activities, high frequency oscillations and sleep microstructure along with sleep structure changes after starting the chronic high-frequency stimulation and correlated the results with the clinical outcome of the therapy. Detailed anatomical reconstruction was performed to study the exact location of the lead within and around the ANT.
Results: 81% of the patients had interictal epileptiform discharges (IED) in the ANT in sleep and 69% in wakefulness. 6 patient had recorded seizures. The IEDs and seizures tended to follow the cortical activity. The responder patients had significantly more IED in the thalamus than non-responders in sleep (p=0,0002), but not in awake (p=0,604), and in case of hitting the IED performing regions in the ANT increased the odds ratio of being a responder from 1.6 to 17.5. Significant HFO activity difference was found in the ANT between responders and non-responders. Detailed analysis of intrathalamic sleep spindles revealed a major role of ANT in spindle generation that correlated with the neuropsychological performance of the patients. IID associated spindles had altered morphology compared to HFO activity associated ones indicating HFO activity being a marker of physiological but not pathological activity. Strong shifts in patterns of sleep spindle-related thalamocortical activity and connectivity were seen along the antero-posterior axis of the ANT. Sleep microstructure changes were recorded during stimulation ON periods.
Conclusions: We concluded that subacute to chronic recordings within the ANT can help selecting patients and aid intrathalamic targeting. The neuromodulatory effect of DBS therapy largely relies on the modification of the sleep structure and sleep related epileptogenesis.
Funding: Please list any funding that was received in support of this abstract.: 2017-1.2.1-NKP-2017-00002 (NKFIH), OTKA-128117 (NKFIH).
Neurophysiology