Quantitative and qualitative interpretation of neuropsychological data in the assessment of temporal lobectomy candidates

Neuropsychologists who serve as members of an epilepsy surgery team are often asked to provide information regarding localized cerebral dysfunction that may relate to the seizure focus in patients with intractable temporal lobe epilepsy (TLE). However, the rate at which neuropsychological (NP) assessment results correspond with the side of seizure focus (i.e., left vs. right) in TLE patients is unknown. The majority of literature in this area has focused on the ability of single NP tests to detect lateralized cognitive dysfunction in groups of TLE patients, with mixed findings and few consistent replications. The primary purpose of this study was to examine the rate at which qualitative clinician interpretations of NP profiles agree with seizure lateralization as determined by a multidisciplinary surgery team in temporal lobectomy candidates. Quantitative analyses of single NP test scores and groups of test scores (i.e., cognitive domain composite scores) were also conducted to examine their effectiveness in discriminating left from right TLE groups. Only four of the 19 NP test variables and three of the nine composite cognitive domain scores significantly differed between the groups. However, clinician interpretation of NP profiles agreed with the surgery conference team's determination of seizure laterality in two-thirds of cases. These findings suggest that qualitative aspects of NP performance play an important role in identifying lateralized cerebral dysfunction in TLE patients, and provide additional support for the use of NP assessment results in the selection of temporal lobectomy candidates.