Epileptic K-complexes: An Underrated yet Potential Diagnostic Marker in Idiopathic Generalized Epilepsy
Abstract number :
2.147
Submission category :
3. Neurophysiology / 3C. Other Clinical EEG
Year :
2024
Submission ID :
138
Source :
www.aesnet.org
Presentation date :
12/8/2024 12:00:00 AM
Published date :
Authors :
Presenting Author: Hassan Souidan, MD – Detroit Medical Center-Wayne State University
Taha Ataya, MD – Detroit Medical Center-Wayne State University
Hana Danieli, MD – University of Louisville
Abdelrahman Alsherbini, MD – Wayne State University
Arichena Ramanathan Manmatharayan, MD – Detroit Medical Center - Wayne State University
Farah Abdelhak, Student – Wayne State University
Mona Elsayed, MD – Wayne State University School of Medicine
Rationale:
Since its discovery in the 1930s, the K-complex has been variously interpreted as representing an arousal phenomenon, a sleep promoting response, and many other theories. Clinically, it remains a reassuring signal that the patient has achieved a sleep state, specifically stage II1. A detailed description of an epileptic K-complex (EKC) and its association with idiopathic generalized epilepsy (IGE) was not widely circulated until 1965 when Niedermeyer reported this phenomenon as a disturbance in the sleep EEG, which he later termed 'dyshormia,' a pathological arousal during sleep2. To our knowledge, the largest study on EKC included 107 patients with IGE found no significant impact of clinical variables on the presence of EKCs. In this observational study, we report our observations of epileptic sleep structures in patients with IGE to assess their clinical significance and implications.
Methods: We retrospectively reviewed long-term EEGs from four randomly selected patients with idiopathic generalized epilepsy (IGE), classified according to the International League Against Epilepsy (ILAE) criteria. Each EEG was analyzed for the presence of epileptic K-complexes (EKCs) and/or epileptic sleep spindles. The review included 24-72 hours of EEG recordings, and identification of EKCs and epileptic sleep spindles was conducted through visual inspection by a board-certified epileptologist.
Results: A total of four patients with IGE were identified, three of whom were female and one male, aged between 21 and 38 years. Two patients were diagnosed with Juvenile Absence Epilepsy (JAE) and had absence and myoclonic seizures. Their EEGs showed two distinct patterns of generalized interictal discharges i) 3-4Hz spike-wave discharges, and ii) epileptic K-complexes preceded by diffuse 4-6Hz spike-wave spindles (Fig. 1). The other two patients were diagnosed with Juvenile Myoclonic Epilepsy (JME) and had absence, myoclonic, and generalized tonic-clonic seizures. Their EEGs recorded four types of generalized interictal discharges; the previously mentioned (i) 3-4Hz spike-wave discharges, and (ii) epileptic K-complexes preceded by diffuse 4-6Hz spike-wave spindles, in addition to (iii) very frequent epileptic K-complexes which were preceded and sometimes overridden by 8-10Hz epileptic sleep spindles (Fig. 2), and (iv) independent synchronous 10-12Hz epileptic sleep spindles.
Conclusions:
Epileptic K-complexes (EKCs) were observed in all patients with idiopathic generalized epilepsy (IGE) identified in this observational study. Our findings suggest that recognizing EKCs as a distinct EEG abnormality could enhance the diagnostic process for IGE, provided these results are validated in larger patient samples. The specific EEG patterns identified correlated with particular IGE diagnoses and highlight the need for statistical validation. Although previous studies did not find significant clinical correlations, we recommend further research to assess the morphologies, frequencies, and treatment responses of EKCs in relation to specific IGE diagnoses. Additionally, it is crucial to avoid overreading normal K-complexes to prevent diagnostic errors.
Funding: No funding
Neurophysiology