Although a great majority of the patients with juvenile myoclonic epilepsy had continuing seizures after a follow-up of 20 years, almost all had either 5-year remission or a substantial alleviation of the myoclonic seizures.
This study evaluated the EEG findings of patients whose seizures were associated with a possible autoimmune etiology. Our aim was to find clues to distinguish patients with antineuronal antibodies (Ab) through EEG studies. We reviewed our database and identified antineuronal Ab positive epilepsy patients with or without autoimmune encephalitis. These patients had Abs to N-methyl-d-aspartate receptor (NMDAR) (n = 5), glycine receptor (GLY-R) (n = 5), contactin-associated protein-like 2 (CASPR-2) (n = 4), uncharacterized voltage-gated potassium channel complex (VGKC) antigens (n = 2), glutamic acid decarboxylase (GAD) (n = 2), Hu (n = 1), and amphiphysin (n = 1). The control group consisted of 21 seronegative epilepsy or encephalopathy patients with similar clinical features. EEG findings were compared between the groups in a blindfolded design. We did not find any significant difference in EEG findings between antineuronal Ab positive epilepsy patients and seronegative control group. It was remarkable that four seropositive but none of the seronegative patients presented with nonconvulsive status epilepticus (NCSE) or focal motor status epilepticus. Continuous theta and delta rhythms were observed in 5 (71%) seropositive patients with autoimmune encephalitis and 2 (25%) seronegative patients. Eight (40 %) seropositive patients showed a frontal intermittent rhythmic delta activity (FIRDA) pattern as opposed to 5 (24%) seronegative patients. Two patients with NMDAR Ab positivity showed rhythmic delta waves superimposed with beta frequency activity resembling "delta brush" pattern. EEG seems as a limited diagnostic tool in differentiating epilepsy and/or encephalopathy patients with a possible autoimmune etiology from those without. However, antineuronal Abs associated with encephalitis should be considered in the etiology of status epilepticus forms. A possible autoimmune etiology for seizures may be considered in the presence of continuous slow waves, FIRDA, and delta brush pattern in the EEG.
Our results underlined that DBP is not unique to NMDAR encephalitis; it may very rarely occur in MTLE with good prognosis after surgery and second, in ICU patients who have high mortality rate. Therefore, the presence of this pattern should alert the clinician for NMDAR encephalitis but other possible etiologies should not be ignored.
SUMMARYPurpose: Studies on seizures only with an alteration of consciousness were limited mainly to generalized epilepsy. This seizure type has been described rarely in focal epilepsy. We aimed to analyze the semiologic features of this seizure type in focal and generalized epilepsies in a blinded design. Methods: A total of 338 seizure videos in 100 patients were included exclusively by semiologic criteria. Two investigators evaluated the seizure semiology (aura, seizure duration, blinking, mild motor phenomena including automatisms, and so on) from the videos. Primarily the ictal electroencephalography (EEGs) studies and all laboratory findings were evaluated for the localization of the epileptogenic zone and delineating the syndromes, in the second step. Key Findings: Of the focal epilepsy patients (n = 57), the epileptogenic zone could be localized to the temporal (n = 20), frontal (n = 9), and parietooccipital (n = 3) regions. The most common etiology of the generalized epilepsy patients (n = 43) was presumably genetic (n = 33). The presence of aura (none in generalized epilepsy vs. 35% in focal epilepsy; p = 0.0008), lack of blinking (19.3% in focal vs 65.1% in generalized epilepsy; p = 0.01), and longer seizure duration (generalized 14.3 ± 17.7 s vs focal 54.9 ± 40.1 s; p < 0.0001) are significantly associated with focal epilepsy, whereas high seizure frequency (p = 0.002), family history of epilepsy (p = 0.016), and responsiveness to therapy (p = 0.004) point to generalized epilepsy with logistic regression analysis. Significance: Seizures consisting mainly of an alteration in consciousness may originate from any brain lobe in focal epilepsies and also occur in generalized epilepsies. Several semiologic and clinical features that help to differentiate between focal and generalized epilepsy should be considered in the syndrome diagnosis.
The focal findings in adult absence epilepsy patients could have some unknown etio-pathogenetic and prognostic implications. We emphasize the cautious interpretation of isolated interictal focal EEG abnormalities to prevent a wrong diagnosis of focal epilepsy in patients who may indeed suffer from generalized epilepsy.
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