A study of clinical and EEG patterns in patients with Idiopathic generalized epilepsy

 

Soni Girish¹, Jagiasi Kamlesh^2*, Singh Rakesh³, Chheda Akash⁴, Kadam Nikhil⁴, Ansari Afroz⁴

 

¹Associate Professor, ²Professor, ³Assistant Professor, ⁴Resident, Department of Neurology, Grant Govt. Medical College and Sir JJ Group of Hospitals, Byculla, Mumbai 400008.

Email: kamleshjagiasi@yahoo.com

 

Abstract              Background: Idiopathic generalized epilepsies (IGE) are a group of disorders in which EEG shows generalized, bilateral, synchronous, symmetrical spike wave complex and constitute one third of all epilepsies. Patients with IGE have normal neurological status in inter-ictal period and no abnormality on brain imaging. Inter-ictal EEG shows normal background and generalized discharges such as spikes, polys-pikes, poly-spike/spike and waves. ¹In developing countries like India, focal seizures due to Tuberculoma, Neurocysticercosis and scar are common, but idiopathic generalized epilepsy still forms a measurable bulk contributing to seizure morbidity. IGE can have focal discharges in addition to generalized discharges adding to the confusion.² Thus, it is important to know about the clinical and EEG features of IGE, as treatment and prognosis varies. Aims and Objectives:To study clinical and EEG patterns in patients with Idiopathic Generalized Epilepsy. Methodology: This was a cross-sectional retrospective study in patients with Idiopathic Generalized epilepsy at the Department of Neurology at tertiary health care center during one year period i.e. January 2016 to January 2017 as regards to their seizure types, EEG patterns and syndromic epilepsy diagnosis. Sleep and Awake EEG were done for at least 30 minutes. Those with normal EEG on first time; underwent repeat sleep and awake EEG for 60 minutes. The data was presented in the tabular form and expressed in percentages. Results: 65 patients with IGE above the age of 5 years were included in the study. The majority of the patients were in the age group of 16-30 years (44.62%), followed by 31-45 years (23.07%); 6-15 years (18.46%); 46-60 years (13.84%); Females (61.54%) were more affected than males (38.46%).  Various types  seizure patterns were GTCS alone in 23.08% followed by Absences alone in 20.00%,  GTCS + myoclonic jerksin 13.85%,  GTCS + absences in 12.31%,  Myoclonic jerks in 7.69%,  Absences and myoclonus in 6.15%,  GTCS + absences + myoclonic jerks  in 6.15%,  Atonic drop in 4.62%,  Atonic drop and myoclonic jerks  in 3.08%,  Atonic drop and absence in 3.08%. EEG pattern was Abnormal in 81.54% and normalin 18.46% even with repeated EEG studies. Focal discharges were seen in 32.30% of patients, predominantly from fronto-central region.  The focal discharges were unilateral in 71.42% cases and were synchronous bilateral in the remaining 28.57%.Occipital rhythmic intermittent delta activity (ORIDA) was seen in 15.4% patients. Photic stimulation accentuated discharges in all 14 patients with JME whereas hyperventilation induced discharges in 92.3%of childhood absence epilepsy. Abortive generalized bursts of discharges (<2 seconds) constituted 53.08% of abnormal generalized EEG pattern whereas in the remaining 46.92%, bursts were more than 2seconds. Poly-spike, spike wave discharges were seen exclusively with JME. Conclusions: It can be concluded from our study that the majority of the patients were in the age group of 15-30 and majority were females. Most common seizure types were GTCs alone followed by absences alone followed by GTC + myoclonic jerks. Focal discharges can be seen with IGE, mostly from the frontocentral region. Also ORIDA can be seen in generalized epilepsy particularly CAE. Polyspike discharges are exclusively seen with JME.

Key Words:  EEG (Electro Encephalography), GTCS (Generalized Tonic Colonic Seizure), Myoclonic jerks, Absence.