Neuropsychological functioning in children with temporal lobe epilepsy and hippocampal atrophy without mesial temporal sclerosis: a distinct clinical entity?

Unilateral hippocampal atrophy (HA) is considered as a precursor of mesial temporal sclerosis (MTS) in some patients with temporal lobe epilepsy. However, in other cases, it has been suggested that HA without MTS may constitute a distinct epileptic entity. Hippocampal atrophy without MTS was defined as HA without T2-weighted hyperintensity, loss of internal architecture, or associated lesion seen on the MRI data. To date, no study has focused on the cognitive pattern of children with epilepsy with HA without MTS. The objectives of the present study were to characterize the cognitive profile of these children and to investigate the presence (or the absence) of material-specific memory deficits in these young patients, as found in patients with MTS. Toward this end, 16 young patients with epilepsy with either left or right HA without MTS completed a set of neuropsychological tests, assessing overall intelligence, verbal memory and nonverbal memory, and some aspects of attention and executive functions. Results showed normal intellectual functioning without specific memory deficits in these patients. Furthermore, comparison between patients with left HA and patients with right HA failed to reveal a material-specific lateralized memory pattern. Instead, attention and executive functions were found to be impaired in most patients. These results suggest that HA may constitute a distinct epileptic entity, and this information may help health-care providers initiate appropriate and timely interventions.