Neuropsychological profile of adult patients with nonsymptomatic occipital lobe epilepsies

To explore the neuropsychological and neurobehavioral profile in adult patients affected by nonsymptomatic (cryptogenic and idiopathic) occipital lobe epilepsy (OLE), with normal intelligence, we enrolled 20 adult patients with nonsymptomatic OLE and 20 age-, sex-, and education-matched healthy subjects. All participants underwent neuropsychiatric assessment scales, and standardized neuropsychological tests tapping memory, executive functions, constructional, visuospatial and visuoperceptual skills. After Bonferroni correction for multiple comparisons, patients performed significantly worse than controls on several tests tapping complex visuospatial skills and frontal lobe functions. The analysis of single patients' performance revealed that a significantly higher number of OLE patients achieved age- and education-adjusted pathological scores on three tests (Benton Judgment of Line Orientation Test, Freehand Copying of Drawings Test, color-word interference task of Stroop test) with respect to controls. Patients did not differ from control subjects on neuropsychiatric aspects. The direct comparison between OLE subtypes showed that cryptogenetic OLE patients tended to achieve lower scores than idiopathic OLE patients on most tests, but no difference between the two groups was fully significant. In summary, patients with nonsymptomatic OLE can be affected by clinically relevant impairments in selected neuropsychological domains: complex visuospatial skills and executive functions. It could be speculated that frontal and visuospatial cognitive deficits might be the result of epileptic activity spreading within a neural network that includes structures far beyond the occipital lobe.