Electroencephalogram Abnormalities in Neurologically Healthy Older Adults
Abstract number :
3.489
Submission category :
3. Neurophysiology / 3C. Other Clinical EEG
Year :
2023
Submission ID :
1475
Source :
www.aesnet.org
Presentation date :
12/4/2023 12:00:00 AM
Published date :
Authors :
Presenting Author: Joe James, MD, MRCP – Cleveland Clinic
Linda Franic, BA – Cleveland Clinic; Balu Krishnan, PhD – Cleveland Clinic; Mary Lenk, MS – Cleveland Clinic; Imad Najm, MD – Director of Epilepsy Center, Neurological Institute, Cleveland Clinic; Vineet Punia, MD, MS – Staff Physician, Neurological Institute, Cleveland Clinic
Rationale: Older adults are among the highest-risk age groups for new-onset epilepsy. In our rapidly aging population, it is critical to understand the natural history of late-onset epilepsy and identify its early biomarkers, including the pre-clinical stage before seizure onset. Electroencephalography (EEG) remains a fundamental, non-invasive tool for measuring electrophysiological and epileptiform abnormalities, including epilepsy diagnosis. The role of epileptiform abnormalities in dementia, especially Alzheimer's disease, has received heightened attention in recent years. However, limited data exists on EEG findings in neurologically healthy older adults. We are attempting to fill this knowledge gap using an ongoing prospective, longitudinal observational study.
Methods: Cleveland Clinic Brain Study (CCBS) is an ongoing prospective longitudinal observational study, enrolling 50 years and older adults who are neurologically healthy based on a thorough history and neurological examination. An overnight EEG using the international 10-20 system captures both awake and sleep states. The EEGs are reviewed by a board-certified technologist and/or neurologist and independently reviewed by a board-certified epileptologist. The interictal EEG findings are classified as normal transients, non-epileptiform abnormalities (including generalized or regional delta slow), and epileptiform discharges (IEDs) based on International Federation of Clinical Neurophysiology (IFCN) criteria. Sharp transients, which are not normal transients and do not fulfil the IFCN criteria of IEDs, are classified as epileptiform transients of unknown significance. A qualitative statistical analysis of abnormalities was performed, including their distribution by age group.
Results: A total of 495 EEGs were reviewed and reported here. The median age of study subjects is 60 years (range 50 to 86), and 362 subjects (73.1%) are females. As noted in Table 1, 45% of the subjects are in their fifties, 41% in their sixties, and the rest are 70 years or older. EEG abnormalities were observed in 156 (31.5%) subjects, almost all showing focal slowing (n = 152; 97.4%). IEDs were seen in 20 (4.0%) subjects, including 19 with sharp waves and two with spikes. As noted in Table 1, the IED prevalence is similar in the sixth and seventh decade of life. Epileptiform transients of unknown significance were noted in 40 (8.1%) subjects. Subclinical rhythmic EEG discharges of adults (SREDA) was noted in seven (1.4%) subjects, including three subjects with coexisting IEDs.
Conclusions: The IED prevalence in neurologically healthy older adults seems much higher than reported in young adults. The long-term follow-up of these subjects in CCBS through clinical (yearly) and electrophysiological (alternative-year) monitoring will clarify the significance of these abnormalities, reveal EEG biomarkers of late-onset epilepsy, inform their role in cognition decline, and guide early interventions.
Funding: Ohio Department of Higher Education
Neurophysiology