Generalised periodic epileptiform discharges (GPEDs) are very rare patterns and are classified as periodic short-interval diffuse discharges (PSIDDs), periodic long-interval diffuse discharges (PLIDDs) and suppression-burst patterns according to the interval between the discharges. In this study we analysed the demographics, history of the seizures during the current illness, mental status, diagnosis, metabolic abnormalities, neuroimaging studies and prognosis of 37 adult patients who had GPEDs in their EEGs. Ages ranged from 17 to 82 years (mean 45 years). There were 19 males and 18 females. The most common aetiology of GPEDs was metabolic and/or infectious disease which was established in 22 patients (59.5%). Other aetiologies included subacute sclerosing panencephalitis (SSPE) in 11 patients (29.7%) and Creutzfeld-Jakob disease (CJD) in 4 patients (10.8%). We showed that structural lesions were found in most of the patients with GPEDs, but concurrent metabolic abnormalities and/or infectious diseases were also detected. Consciousness was impaired and clinical conditions were poor in various degrees in all of the patients when GPEDs were seen. Relatively little is known regarding the mechanism of GPEDs. When GPEDs are seen in EEG, the patient should carefully be checked for metabolic abnormalities and/or infectious diseases and intracranial lesions. GPEDs may be helpful in the determination of prognosis, showing the poor prognosis especially in cases when suppression-burst pattern is seen.

In this study we investigated the structural lesions of patients with periodic lateralized epileptiform discharges (PLEDs) to determine the possible relationship of lesions to PLEDs' localization on EEG and to metabolic abnormality. Clinical findings and electroencephalography (EEG), computerized tomography (CT) and magnetic resonance imaging (MRI) of the 71 adult patients with PLEDs were evaluated. Stroke, herpes encephalitis and intracranial tumor or abscess were the most common etiological factors. Cortical gray matter and adjacent subcortical white matter lesions were detected in 64.7%, cortical gray matter lesions in 11.3% and subcortical white matter lesions in 4.2% of the patients. Although it is thought that PLEDs occur mostly with acute lesions, chronic lesions causing PLEDs were found in 35.2% of the patients. Bilateral lesions were detected in 19.7% and 33.8% of the patients had metabolic abnormality. PLEDs localized the region of the lesion in 63.4% of the patients. PLEDs are usually self-limited features, but chronic PLEDs were detected in 5 patients in this study. Acute structural lesions involving cortical gray matter with adjacent subcortical white matter were found in most of the patients with PLEDs, but the lesion localization and age, acute or chronic, varied.

ECS is more common in females. It may overlap with photosensitivity but be independent from photosensitivity. It may be seen in different epilepsy syndromes including IOE which was not reported previously.

In this study we reviewed the clinical, electrophysiological and neuroimaging data of 21 patients with epilepsia partialis continua (EPC), which is a rare form of epilepsy with focal motor seizures persisting hours to years. We found infections, cerebrovascular events and tumors as the most common causes of EPC in adults. SSPE was also shown as a cause of EPC. EPC in SSPE patients was resistant to therapies and persisted more than 1 year. EPC is usually a predictor of poor outcome and 29% of patients died after EPC in this study. As prognosis is usually bad and as response to treatment is poor in patients who had EPC, early diagnosis and treatment of the underlying cause is important. Although the most common etiologies are infections, cerebrovascular events and tumors, if EPC persists several months SSPE should be kept in mind as a rare cause of EPC. MRI should be repeated in chronic cases to show dysplastic cortex, which was shown in 1 patient in this study.

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