The complementary value of sleep-deprived EEG in childhood onset epilepsy

Early classification of childhood focal idiopathic epilepsies: is it possible at the first seizure?

PURPOSES

To evaluate the possibility of early syndrome classification of idiopathic partial epilepsies in children at the first seizure.

PATIENTS AND METHODS

In this observational study we prospectively evaluated 298 patients, aged between 1 month and 17 years and consecutively referred for the first unprovoked focal seizure. The whole cohort included 133 patients; the final analysis was carried out on 107 (59 males) individuals. Age at the first seizure ranged between 2.3 and 13.0 years. Clinical and EEG data of all patients were independently reviewed by two medical doctors. Patients were followed-up for at least 5 years, with a mean period of follow-up of 6.9 years.

RESULTS

After the first seizure, a specific syndrome could be diagnosed in eighty (74.7%) children. In particular, Childhood Epilepsy with Centro-Temporal Spikes (CECTS) 42.9% of cases, Panayiotopoulos Syndrome (PS) 28.9%, idiopathic childhood occipital epilepsy of Gastaut (ICOE-G) 2.8%. Unclassified cases were 25.4%. At the end of the follow-up, the diagnosis was confirmed in 72 of 80 children (90%): BCECTS 89% of patients, PS 90% and ICOE-G 100%: among the unclassified cases, in 11 patients (40.7%) the diagnosis did not change, whereas 16 patients (59.3%) evolved into other syndromes or into atypical forms.

CONCLUSIONS

At the onset an initial diagnosis is possible in the majority of cases; epilepsy syndromes can be identified at the time of the initial diagnosis and at follow up this diagnosis has not to be revised in 90% of the cases.

Controversial issues on EEG after sleep deprivation for the diagnosis of epilepsy

EEG after sleep deprivation (SD-EEG) is widely used in many epilepsy centers as an important tool in the epilepsy diagnosis process. However, after more than 40 years of use, there are a number of issues which still need to be clarified concerning its features and role. In particular, the many scientific papers addressing its role in epilepsy diagnosis often differ remarkably from each other in terms of the type of patients assessed, their description and study design. Furthermore, also the length and the type of EEG performed after SD, as well as the length of SD itself, vary dramatically from one study to another. In this paper we shortly underscore the abovementioned differences among the different reports, as well as some interpretations of the findings obtained in the different studies. This analysis emphasizes, if needed, how SD-EEG still represents a crucial step in epilepsy diagnosis, and how additional, controlled studies might further shape its precise diagnostic/prognostic role.

The adolescent or adult with generalized tonic-clonic seizures

Primary and secondary generalized tonic-clonic seizures (GTCs) together constitute up to 50% of adolescent and adult patients with epilepsy as diagnosed by history and EEG. Syncope and psychogenic nonepileptic seizures are major differential diagnoses and must be carefully excluded in therapy-resistant cases. Individual episodes can have up to seven phases in secondarily generalized GTCs. The distinction between primary and secondary GTCs depends mainly on history and EEG, and yield can be improved with sleep deprivation or overnight recording. Epilepsies with primary or unclassified GTCs can respond to any one of the five broad-spectrum antiepileptic drugs (AEDs): valproate, lamotrigine, levetiracetam, topiramate and zonisamide. Unless a focal onset is clearly confirmed, a sodium-channel blocking AED should not be used in the initial treatment of these conditions.

Levetiracetam reduces the frequency of interictal epileptiform discharges during NREM sleep in children with ADHD

BACKGROUND

Symptoms of attention deficit hyperactivity disorder (ADHD) are more common in children with epilepsy than in the general paediatric population. Epileptiform discharges in EEG may be seen in children with ADHD also in those without seizure disorders. Sleep enhances these discharges which may be suppressed by levetiracetam.

AIM

To assess the effect of levetiracetam on focal epileptiform discharges during sleep in children with ADHD.

METHOD

In this retrospective study a new semi-automatic quantitative method based on the calculation of spike index in 24-h ambulatory EEG recordings was applied. Thirty-five ADHD children, 17 with focal epilepsy, one with generalised epilepsy, and 17 with no seizure disorder were evaluated. Follow-up 24-h EEG recordings were performed after a median time of four months.

RESULTS

Mean spike index was 50 prior to levetiracetam treatment and 21 during treatment. Seventeen children had no focal interictal epileptiform discharges in EEG at follow-up. Five children had a more than 50% reduction in spike index. Thus, a more than 50% reduction in spike index was found in 22/35 children (63%). Out of these an improved behaviour was noticed in 13 children (59%).

CONCLUSION

This study shows that treatment with levetiracetam reduces interictal epileptiform discharges in children with ADHD. There is a complex relationship between epilepsy, ADHD and epileptiform activity, why it is a need for prospective studies in larger sample sizes, also to ascertain clinical benefits.