Utility of the Repeatable Battery for the Assessment of Neuropsychological Status in Focal Epilepsy Patients in an Arab Cohort

Patients with temporal lobe epilepsy account for about 30 to 40% of the pharmacoresistant epilepsy and can be associated with impairments in multiple cognitive domains, including memory, language, executive function, intelligence and motor speed. Research studies investigating the generalized nature of cognitive impairment in temporal lobe epilepsy, which accounts for the commonest form of focal epilepsy, suggest that structural brain changes might be present outside the epileptogenic zone. Many studies have shown the involvement of extratemporal regions [1-12]. Significant bilateral volumetric reductions in frontoparietal regions have been reported in TLE male patients [1] as well as whole brain volumetric abnormalities [2]. Riley et al. [3] reported widespread disturbances in four white matter regions, namely, anterior temporal lobe, posterior mesial temporal lobe, cerebellum ipsilateral, as well as frontoparietal lobe contralateral to the side of seizure onsetin temporal epilepsy patients. The authors reported an association between three of these abnormal white matter clusters and distinct cognitive functions using the Repeatable Battery of Neuropsychological Status (RBANS). The mesial temporal and anterior temporal lobes clusters were correlated with performances on immediate and delayed memory. The cerebellar, an extra-temporal region, was correlated with executive function performances. Compared to temporal lobe epilepsy, extratemporal epilepsies occur in approximately 20% of patients with partial epilepsy with Frontal Lobe Epilepsy (FLE) being the most prevalent type of extra-temporal epilepsy. Much of the literature has examined differences in cognitive performances between patients with FLE and temporal lobe epilepsy. The research has found that FLE patients have higher IQ and less significant memory difficulties than patients with temporal lobe epilepsy [13]. Moreover, patients with FLE have shown to perform more poorly on executive function measures, motor programming/sequencing and coordination, phonological processing, visuomotor and visuoperceptual speed and complex visuoconstruction. Detailed neuropsychological evaluations are clinically valuable, but time-consuming. Some research has suggested the use of short cognitive screening measures for use with pre-ictal, ictal and post-ictal patients. For example, Andrewes et al. [14] found a significant association between side of seizure focus and selective memory impairment, postictally. The Montreal Cognitive Assessment (MoCA) was found to detect mild cognitive impairment in cryptogenic epilepsy patients despite normal Mini Mental State Examination (MMSE) scores and has been recommended as a screening test for patients with epilepsy [15].