A prospective longitudinal study on visuo-cognitive development in Dravet syndrome: Is there a "dorsal stream vulnerability"?

A group of five DS patients whose first development was already reported were longitudinally followed up till the scholar age. Beside the general and epileptic clinical evolution, visual and cognitive functions were investigated in order to define their trajectory and possibly provide information about mechanisms of cognitive decline as well as to improve prognosis and tertiary prevention. Neuropsychological assessment was performed with a test battery investigating the development of visual function that progressively integrates into extrastriate components and higher cognitive skills (global form and motion coherence, stereopsis, crowding cards, ABCDEFV battery, general intelligence and specific cognitive tests). Main results showed a fall in visuo-motor items including global motion coherence and specific cognitive skills, presenting a continuity of the visual function deterioration extended from basic abilities to visuo-motor dorsal pathway skills. Moreover, a case whose previous visual and cognitive functions had been in the normal range began showing a visual deterioration with increasing age, followed by the cognitive decline; that prevents from excluding in early ages a poor development in presence of a normal visual function. A dorsal stream vulnerability seems thus shown in this sample of DS patients, like in other genetic syndromes (Williams, Prader Willi. fragile-X), providing new information about mechanisms underlying cognitive decline and suggesting a possible strategy to improve their neuropsychological outcome. Larger cohorts may confirm whether these findings are part of a specific pattern of DS neuropsychological phenotype.

Functional hemispherectomy in children with epilepsy and CSWS due to unilateral early brain injury including thalamus: sudden recovery of CSWS.

PURPOSE: To try to prove in patients with refractory symptomatic epilepsy due to early brain injury involving thalamus and complicated by CSWS the effects of the isolation of the injured hemisphere, performed with functional hemisperectomy, on epilepsy, namely on CSWS. METHODS: Full clinical follow-up before and after surgery of two cases with CSWS onset at four years in whom functional hemispherecomy was performed with resection of inter-hemispheric connections. RESULTS: An immediate effectiveness of the surgical treatment was observed on both epileptic evolution (no more seizures) and EEG abnormalities. In particular, CSWS completely disappeared, together with a concurrent progressive improving of the cognitive and behavioural disorders. DISCUSSION: The isolation of the injured hemisphere through the section of inter-hemispheric cortico-cortical connections could prevent the contralateral diffusion of discharges coming from the injured cortex and cortico-thalamic network, favouring a normal function of thalamo-cortico-thalamic circuitries in the healthy hemisphere. That could explain the disappearance of CSWS after surgery in our patients and the consequent improvement of cognitive abilities and behaviour.

Hemiconvulsion-hemiplegia-epilepsy syndrome: early magnetic resonance imaging findings and neuroradiological follow-up.

We describe a case of hemiconvulsion-hemiplegia-epilepsy (HHE) syndrome documented by longitudinal magnetic resonance imaging (MRI). A two-year and nine-month-old boy had a prolonged hemiconvulsion during fever followed by right hemiparesis. Seven days later the imaging abnormality on T2 and diffusion-weighted images (DWI) was limited to the white matter of the left hemisphere. One month later severe gliosis and unilateral brain atrophy were already evident. MRI is useful in the early stages of prolonged seizures and T2 and DWI abnormalities appear to be well correlated with parenchymal damage that results from sustained ictal activity. The neuroradiological findings in our case and in the few HHE patients reported in the literature seem to be very characteristic and, if confirmed in larger series, could permit an early diagnosis.