Deficits in Outpatient Neuropsychological Memory Test Are Predicted by the Load of Hippocampal HFOs
Abstract number :
1.436
Submission category :
1. Basic Mechanisms / 1C. Electrophysiology/High frequency oscillations
Year :
2022
Submission ID :
2232866
Source :
www.aesnet.org
Presentation date :
12/3/2022 12:00:00 PM
Published date :
Nov 22, 2022, 05:28 AM
Authors :
Sina Sadeghzadeh, AB – Stanford University School of Medicine; Eugene Liang, BA – Undergraduate, Molecular and Cell Biology, Berkeley University; Su Liu, PhD – Assistant Professor, Institute of Speech-language Pathology and Brain Science; James Stieger, PhD – Postdoctoral Scholar, NEUROLOGY AND NEUROLOGICAL SCIENCES, Stanford University; Lamara Allen, BA – Undergraduate, Program in Human Biology, Stanford University; Kurt Qing, MD, PhD – CLINICAL INSTRUCTOR, NEUROLOGY & NEUROLOGICAL SCIENCES, Stanford University; Vivek Buch, MD – CLINICAL ASSISTANT PROFESSOR, NEUROSURGERY, Stanford University; Gayle Deutsch, PhD, ABPP – Neuropsychologist, Neurology, Stanford University; Josef Parvizi, MD, PhD – Professor-Univ Med Line, Neurology, Stanford University
This is a Late Breaking abstract
Rationale: The presence of high frequency oscillations (HFOs) has been linked to impairments in acute cognitive performance. However, it is unclear whether total HFO burden can be indicative of overall cognitive status and more chronic cognitive decline. Here, we explore the relationship between hippocampal HFO burden in patients with temporal lobe epilepsy (TLE) and their performance in neuropsychological tests of memory at baseline.
Methods: Ten patients (five men, age = 36 ± 9.51) with medically refractory TLE who underwent invasive monitoring at Stanford University Medical Center were retrospectively selected. All patients completed a verbal recognition memory test, and 8 patients completed Rey Auditory Verbal Learning Test (RAVLT) as part of their preop neuropsychological evaluation. Baseline HFO load was measured in 1h EEG segments immediately after intracranial EEG set up was completed. We also measured HFO load during the experimental memory task. HFOs were automatically detected using a previously published algorithm (Liu and Parvizi, 2019) and validated using HFOApp, RippleLab, and RMS detector detectors (Zhou et. al., 2021). Channels with the highest HFO rates (counts per time) in each lobe were selected for statistical analysis.
Results: We observed higher HFO rates in the hemisphere of seizure origin (mean ipsilateral HFO rate = 1.94 events/min, mean contralateral HFO rate = 0.74 events/min). Baseline and encoding HFO rates were comparable in all except 2 patients. Performance in the RAVLT positively correlated with performance in the experimental verbal recognition memory test (R = 0.78, p = 0.022). Hippocampal HFO rate at baseline showed a strong negative relationship with performance in the Delayed Recall Trial of the RAVLT (R = -0.85, p = 0.009) and predicted it in a linear regression model (β: -0.48947, p = 4.57e-05). Hippocampal HFO rates during verbal recognition memory test also showed a strong negative relationship with subject task performance (R = -0.82, p = 0.0024) and predicted it in a linear regression model (β: -0.09908, p-value: 0.00117). We confirmed the statistical significance of our observations at the group level using a bootstrap method (mean: -0.57, SD: 0.24, 95% CI: [-1.10, -0.14]).
Conclusions: Cognitive dysfunction is a common and debilitating comorbidity in patients with epilepsy. We present preliminary data suggesting that hippocampal HFO load both at baseline and during memory encoding is negatively correlated with and can predict verbal memory function even during outpatient pre-operative neuropsychological testing. Further investigation with a larger sample size is warranted to better elucidate this relationship. These findings suggest that HFO burden can be used as a biomarker for memory function in epilepsy patients and present pathological HFOs as a potential target for closed loop neuromodulation for cognitive improvement.
Funding: This project was funded by the Stanford Medical Scholars Research (MedScholars) fellowship Discovery Grant.
Basic Mechanisms