Impaired object identification in idiopathic childhood occipital epilepsy.

PURPOSE: To investigate whether children with epilepsy primarily affecting the occipital cortex exhibit impairment of visual object identification and to what extent such a hypothesized dysfunction is related to an interfering functional, rather than structural, process. METHOD: We studied nine children with idiopathic childhood occipital epilepsy (ICOE) and compared them to eight children with lesional posterior cortex epilepsy (PCEs) and to 60 age-matched controls. We applied an "ascendent" paradigm of object identification, using a coarse-to-fine order procedure, which gradually integrated spatial frequency information from the most blurred image to the complete figure. In children with ICOE, we explored how epilepsy-related variables might be related to object identification task. KEY FINDINGS: Children with ICOE and those with PCEs needed more physical information than controls to identify visual stimuli. There was a decreasing accuracy from controls to children with ICOE and from children with ICOE to those with PCEs. Children with ICOE demonstrated slight selective impairment in visuospatial processing and those among them having experienced a higher number of seizures or in whom interictal electroencephalography (EEG) discharges had been present for a longer time, required a higher level of physical information to recognize objects. SIGNIFICANCE: The observation that children with ICOE performed worse than controls in object identification, although better than children with PCEs, might indicate that functional disruption caused by epileptiform EEG abnormalities and seizures, can interfere per se with perceptual processes, even in the absence of a lesion. This effect appears to be detected only by perceptual and cognitive screening.

Visual recognition memory in Alzheimer's disease: repetition-lag effects.

There is considerable evidence that visual recognition memory is largely affected by Alzheimer's disease (AD). Deficits might concern the forming, maintaining, and matching of the memory representation of the visual stimulus, especially when long interitem lags occur. The aim of the present study was to assess the effect of repetition lag on picture identification in mild- and moderate-AD patients, as well as in elderly controls. Participants underwent an old/new paradigm. To manipulate the temporal gradient, short and long lags were introduced between the first and second presentations. Pictures were presented at different levels of spatial filtering, following a coarse-to-fine order. This allowed for the measurement of the amount of physical information required for the identification of stimuli as a function of prior exposure and repetition lag. In the elderly, the magnitude of repetition priming did not differ as a function of interitem lag. Instead, repetition-lag effects interacted with dementia severity, and the capacity to retain memory traces for longer intervals worsened as the disease progresses. Current findings suggest that severe cortical degeneration may render AD patients unable to maintain their perceptual memories, and that dementia severity is a critical variable in the visual recognition memory assessment.

Dysgraphia as a Mild Expression of Dystonia in Children with Absence Epilepsy.

BACKGROUND: Absence epilepsy (AE) is etiologically heterogeneous and has at times been associated with idiopathic dystonia. OBJECTIVES: Based on the clinical observation that children with AE often exhibit, interictally, a disorder resembling writer's cramp but fully definable as dysgraphia, we tested the hypothesis that in this particular population dysgraphia would represent a subtle expression of dystonia. METHODS: We ascertained the prevalence of dysgraphia in 82 children with AE (mean age 9.7) and average intelligence and compared them with 89 age-, gender- and class-matched healthy children (mean age 10.57) using tests for handwriting fluency and quality, based on which we divided patients and controls into four subgroups: AE/dysgraphia, AE without dysgraphia, controls with dysgraphia and healthy controls. We compared the blink reflex recovery cycle in children belonging to all four subgroups. RESULTS: We identified dysgraphia in 17/82 children with AE and in 7/89 controls (20.7 vs 7.8%; P = 0.016) with the former having a 3.4-times higher risk of dysgraphia regardless of age and gender (odd ratio: 3.49; 95% CI 1.2, 8.8%). The AE/dysgraphia subgroup performed worse than controls with dysgraphia in one test of handwriting fluency (P = 0.037) and in most trials testing handwriting quality (P< 0.02). In children with AE/dysgraphia the blink reflex showed no suppression at short interstimulus intervals, with a difference for each value emerging when comparing the study group with the three remaining subgroups (P<0.001). CONCLUSIONS: In children with AE, dysgraphia is highly prevalent and has a homogeneous, distinctive pathophysiological substrate consistent with idiopathic dystonia.