| Poster | Poster Session 09 Program Schedule
02/16/2024
03:30 pm - 04:45 pm
Room: Majestic Complex (Posters 61-120)
Poster Session 09: Epilepsy | Oncology | MS | Infectious Disease
Final Abstract #74
Design of Fronto-Temporal Cognitive Tests in SEEG (Stereoelectrencephalography) using Direct Electrical Brain Stimulation (DBS): Caase-Report.
María Martin, Fleni, CABA, Argentina
Micaela Arruabarrena, Fleni, CABA, Argentina
Abril Marone, Fleni, CABA, Argentina
Gabriela Ugarnes, Fleni, CABA, Argentina
Lucía Crivelli, Fleni, CABA, Argentina
Ricardo Allegri, Fleni, CABA, Argentina
Walter Silva, Fleni, CABA, Argentina
Category: Epilepsy/Seizures
Keyword 1: temporal lobes
Keyword 2: brain injury
Objective:
Introduction
Epilepsy surgery is sometimes necessary as a treatment for patients with drug-unresponsive epilepsy. Pre quirugical invasive neurophysiological evaluations are in some cases, necessary to determine the epileptogenic zone of resection,. One of the most widely used methods currently used is stereoelectroencephalography (SEEG), which applies deep electrodes. This method allows for the observation of cortico-subcortical electroencephalographic activity (EEG) during interictal and ictal states, triggering of habitual seizures with EEDC, and evaluation of the localization of primary motor, language, and primary visual areas. Deep-electrode stimulation in conjunction with SEEG and cognitive testing presents a novel and revolutionary approach to determining cognitive functions, locating them, and predicting post-surgical cognitive deficits.
Objectives
To evaluate the cognitive effects of deep brain stimulation.
To design and select appropriate cognitive tests to measure the cognitive effects of DEBS.
Participants and Methods:
The participant in this study is a 37-year-old male patient with a history of severe epilepsy and refractory seizures. This study follows a single-case design, using a within-subject approach to assess cognitive function and its correlation with deep brain activity, recorded through SEEG. Initially, a comprehensive neuropsychological evaluation was conducted to assess memory, attention, processing speed, language, and executive functions. The results indicated a normal score of 26/30 on the MOCA. The patient showed normal performance in logical memory, serial learning, and the Wechsler Memory Scale, as well as in visuospatial skills. Deficits were observed in attention and working memory tasks, particularly in the Direct (PZ: -3.85) and Inverse Digits (PZ: -1.938) tasks, as well as in the TMB (-8.84) and Stroop (-2.9 and PZ: -2) tests. Additionally there were deficits in both semantic (PZ: -1.74) and phonological (PZ: -1.53) verbal fluency. The study involved placing eleven deep electrodes to record brain activity during rest and cognitive tasks, with varying intensities and specific timings. Initial training trials without brain stimulation confirmed the patient's ability to perform the tests correctly. Subsequently, the same neuropsychological tests were administered during resta and during SEEG, with four electrodes placed in different contact areas.
Results:
Stimulation in the polo-temporal region did not impact semantic recognition, irrespective of intensity (mA) or frequency (Hz). However, in the gyro-orbitofrontal region, at intensities of 1mA, 2mA, and 3mA, with a frequency of 1Hz/30sec, reductions in processing speed and errors in working memory were observed. Gyro-fusiform stimulation affected the task of recognizing famous faces only at an intensity of 3mA and a frequency of 50Hz/5sec, showing no effects at lower intensities. Interestingly, stimulation in the hippocampus did not influence the recognition of previously learned visual stimuli.
Conclusions:
Deep brain stimulation in patients with refractory epilepsy can help elucidate cognitive functions that vary based on electrode placement. These findings suggest the potential for localizing specific cognitive functions and predicting the consequences of their resection. Further research is essential to comprehend and optimize interventions, thereby enhancing the quality of life for patients undergoing epilepsy surgery.
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