Researchers at Children’s Hospital, Boston, MA, and other centers in the US; Winnipeg, Canada; and Barcelona, Spain compared the prevalence during a 14-year period and the type of early developmental lesions in 147 patients with electrical status epilepticus in sleep (ESES), 100 with prominent sleep-potentiated epileptiform activity (PSPEA) and 47 patients without PSPEA as controls. Mean age at EEG recording was 7.9 years. All patients had at least one MRI. Early developmental lesions, chiefly thalamic, were more frequent in cases with PSPEA than in controls (48% vs 19.2%, p=0.002). Thalamic, mainly vascular, lesions occurred in 14% cases vs 2.1% in controls (p=0.037). Early developmental lesions were 14% vascular, 9% periventricular leukomalacia, and 5% cortical malformations. Clinical features of 100 patients with non-REM-PSPEA included developmental regression (50%), language regression (43%), clinical seizures (78%), cerebral palsy (22%), autistic behavior (20%), and attention deficit (7%). [1]

COMMENT. Almost 50% of children with epilepsy and PSPEA have early developmental lesions, especially vascular and thalamic in origin. In patients with language regression, behavioral changes, and epilepsy accompanied by sleep-potentiated EEG abnormalities, the search for thalamic dysfunction may prove to be a helpful anatomic correlate [2]. An MRI should be considered in children with PSPEA.

Electrical status epilepticus during sleep is found in 50% of patients with acquired epileptic aphasia (Landau-Kleffner syndrome) [3], and language regression occurs in 43% of the patients with sleep-potentiated epileptic activity in the EEG. [1]. The present article links acquired epileptic aphasia with sleep-potentiated epileptic activity in the EEG and MRI findings of early thalamic injury. The thalamus has a role not only in the facilitation of seizure activity during non-REM sleep but also in sleep-related electrical status epilepticus and associated language and behavioral regression.