Long-term cognitive outcome of hemiconvulsion-hemiplegia-epilepsy syndrome affecting the left cerebral hemisphere.

Long-term cognitive outcome following hemiconvulsion-hemiplegia-epilepsy (HHE) syndrome has been poorly studied, with little attention to the implications of side of involvement in HHE. This retrospective study describes language lateralization and cognitive performance in five patients with HHE syndrome affecting the left cerebral hemisphere. All of the patients had to have intracarotid sodium amytal testing (IAT) to be included in this study. The mean age of the patients was 30.2 years (range: 13-50). All patients had their hemiconvulsive seizures before age 1(1/2) years (range: 6-13 months). All patients had right-sided hemiatrophy of the body, left mesial temporal sclerosis, and seizures originating from the left temporal lobe. The habitual seizures began at a mean age of 4.5 years (range: 1.5-12 years). Performance on tests of intelligence, verbal memory, and visual memory was examined. Language was represented in the right cerebral hemisphere in three patients, the left hemisphere in one patient, and both hemispheres with predominance on the right side in the fifth patient. Intellectual functioning was in the borderline to extremely low range among the patients with right hemispheric or bilateral representation for language. These patients were variably impaired on measures of verbal and visual memory. The patient with left hemispheric representation for language performed in the average range on tests of intellectual functioning and verbal memory, whereas scores on visual memory were variable. This study demonstrated that reorganization of language to the right cerebral hemisphere or its bilateral representation is common in patients with HHE syndrome affecting the left cerebral hemisphere, and is associated with poor cognitive outcome.

Impaired familiarity with preserved recollection after anterior temporal-lobe resection that spares the hippocampus.

It is well established that the medial-temporal lobe (MTL) is critical for recognition memory. The MTL is known to be composed of distinct structures that are organized in a hierarchical manner. At present, it remains controversial whether lower structures in this hierarchy, such as perirhinal cortex, support memory functions that are distinct from those of higher structures, in particular the hippocampus. Perirhinal cortex has been proposed to play a specific role in the assessment of familiarity during recognition, which can be distinguished from the selective contributions of the hippocampus to the recollection of episodic detail. Some researchers have argued, however, that the distinction between familiarity and recollection cannot capture functional specialization within the MTL and have proposed single-process accounts. Evidence supporting the dual-process view comes from demonstrations that selective hippocampal damage can produce isolated recollection impairments. It is unclear, however, whether temporal-lobe lesions that spare the hippocampus can produce selective familiarity impairments. Without this demonstration, single-process accounts cannot be ruled out. We examined recognition memory in NB, an individual who underwent surgical resection of left anterior temporal-lobe structures for treatment of intractable epilepsy. Her resection included a large portion of perirhinal cortex but spared the hippocampus. The results of four experiments based on three different experimental procedures (remember-know paradigm, receiver operating characteristics, and response-deadline procedure) indicate that NB exhibits impaired familiarity with preserved recollection. The present findings thus provide a crucial missing piece of support for functional specialization in the MTL.

The relationship between parental report on the BRIEF and performance-based measures of executive function in children with moderate to severe traumatic brain injury.

The Behavior Rating Inventory of Executive Function (BRIEF) is a questionnaire that assesses parental observations of behaviors associated with executive function in children in the home environment. The current investigation examines the relationship between the BRIEF and individually-administered neuropsychological tests in children with traumatic brain injury. Forty-eight children with moderate to severe traumatic brain injury were administered the WISC-III and several performance-based tests of executive function (the Wisconsin Card Sorting Test, Trail Making Test Part B, verbal fluency), and a parent completed the BRIEF. Results indicate that the Metacognition Index from the BRIEF correlates with Verbal IQ, but none of the index scores from the BRIEF correlate with any of the performance-based tests of executive function. Results are discussed with respect to the ecological validity of standardized clinical neuropsychological tests of executive function.