L. Parmeggiani

Electroclinical features of idiopathic generalised epilepsy with persisting absences in adult life.

OBJECTIVES: To describe the electroclinical features of typical absences persisting in adult life. METHODS: Twelve adult patients (aged 21 to 56 years) with idiopathic generalised epilepsy featuring typical absences as the prominent clinical feature were studied. All patients underwent a full clinical and neurophysiological investigation including ictal documentation of seizures. RESULTS: Neurological examination and neuroradiological investigations were normal in all cases. Clinical findings included a median age at onset of absences of 14 (range 4-32) years, almost constant tonic-clonic seizures (in 83% of patients), frequent episodes of absence status (in 33% of patients), and associated cognitive or psychiatric disturbances. Interictal EEG findings showed normal background activity, generalised paroxysms of spike waves or polyspike waves, and inconstant focal spikes (in five patients); runs of polyspikes were seen during non-REM sleep. Ictal EEG findings showed generalised spike waves at 3 Hz, sometimes preceded by multiple spikes, or more complex EEG patterns with sequences of polyspikes intermingled with spike waves or polyspike waves, showing discharge fragmentation or variation of intradischarge frequency. CONCLUSION: The results of the present study show that absences persisting in adult life may show particular clinical and EEG patterns, distinct from those in childhood or adolescence.

Frontal inhibitory spike component associated with epileptic negative myoclonus

The aim of this study was to characterize paroxysmal EEG activities associated with epileptic negative myoclonus (ENM) in an epileptic patient presenting with ENM. ENM was predominant in the right upper limb and was correlated to a spike in the left central region. Spikes associated with ENM (SaENM) and spikes unrelated to ENM (SuENM) were identified by the temporal relation between the left central spike and the EMG silent period in the right wrist extensor. SaENM showed a significantly longer duration than SuENM (128 +/- 27 msec versus 92 +/- 21 msec, respectively; P < 0.01). SaENM and SuENM were submitted to spike averaging and topographic mapping. Spike averaging was performed averaging the EEG 640 msec before and after the peak of the spike. Both averaged SaENM and SuENM consisted of a negative spike with highest amplitude at C3 and similar topographic characteristics. The discriminant feature between the two types of spikes was the presence, in averaged SaENM, of a second smaller negative spike, 40 msec after the peak of the spike at C3, whose maxima were distributed over the left frontal region. We labeled this second spike as ENM-related component. We conclude that, in our patient, ENM was associated with a frontal cortical potential suggesting the involvement of frontal areas in the generation of negative myoclonus.

Single-blind, placebo-controlled dose-modification study of vigabatrin in refractory epileptic patients

Thirty patients with drug-resistant epileptic seizures received vigabatrin as add-on treatment in a single-blind, placebo-controlled dose-modification study. After a 3-month baseline period (1 month run-in, 2 months placebo), the patients were given vigabatrin (2 g/day, fixed dose) for 2 months, followed by a 2- to 6-month dose-titration period to achieve the individual optimal dose. Mean monthly seizure frequency significantly decreased from 29.5 seizures during the placebo period to 12.2 while taking vigabatrin, 2 g daily fixed-dose, and to 8.7 during titration phase with vigabatrin, 3 g daily, on average. Sixteen (53%) patients experienced a 50% or greater reduction in seizure frequency compared with placebo, and 3 (10%) patients reported a relevant improvement in seizure severity and duration while on vigabatrin, 3 g daily; therefore, 19 (63%) patients were allowed to continue the treatment on a long-term basis. Adverse effects, mostly drowsiness and weight gain, occurred particularly at the highest vigabatrin dose, although also in any case of mild severity. Serum phenytoin and phenobarbital levels significantly decreased during vigabatrin treatment. These results suggest that vigabatrin in a dose of 2–3 g daily is an effective and safe antiepileptic drug.