BIẾN THỂ BÌNH THƯỜNG TRÊN ĐIỆN NÃO ĐỒ

Abstract

Objectives: To determine the prevalence and the correlation between clinical and paraclinical characteristics with each type of normal variants (NVs) on electroencephalography (EEG). Methods: A retrospective, prospective, cross-sectional descriptive study was conducted on 357 EEG recordings from 348 patients who underwent wakeful and sleep electroencephalography at Nguyen Tri Phuong Hospital from 22 April 2022 to 15 October 2024 and at International Neurosurgery Hospital from 15 February to 15 October 2024. Results: The overall prevalence of NVs, during wakefulness and sleep, was 49.9%, 14.3%, and 45.3%, respectively. The most common NVs were positive occipital sharp transients of sleep (POSTs) at 39.5%, followed by mu rhythm, small sharp spikes, rhythmic mid-temporal discharges, wicket spikes, Lambda waves, midline theta rhythm, breach rhythm, and 14 and 6Hz positive spikes. Factors associated with sleep variants included the absence of imaging abnormalities (OR = 1.58). Factors associated with POSTs included female neuro (OR = 1.91), absence of EEG abnormalities (OR = 2.05), absence of seizures (OR = 3.62), absence of EEG abnormalities (OR = 1.62), and the absence of frontal (OR = 2.24) or focal occipital lesions (OR = 4.82) on neuroimaging. Conclusion: NVs are prevalent during both wakefulness and sleep EEGs; therefore, routine identification of these variants helps distinguish them from interictal epileptiform discharges, thereby improving diagnosis accuracy and epilepsy treatment.