Adequacy of language function and verbal memory performance in unilateral temporal lobe epilepsy

We examined adequacy of language functions, their influence on verbal learning and memory performance, and the relative effects of language function and laterality of seizure focus on the memory performance of 99 left-hemisphere dominant patients with invasively verified epilepsy of left (N = 47) or right (N = 52) temporal lobe origin. Patients with left temporal lobe epilepsy (TLE) scored significantly lower than the right TLE group on several aphasia battery subtests (Visual Naming, Sentence Repetition, Token Test, Reading Comprehension, Aural Comprehension). Adequacy of language function (nominal speech) was significantly related to verbal learning and memory performance for both left and right TLE groups. Finally, comparison of the predictive significance of laterality of TLE and adequacy of language function indicated that language functions (Visual Naming and Aural Comprehension), but not laterality of TLE, were significant predictors for verbal learning and memory performance. It is concluded that: 1) adequacy of basic language functions is particularly compromised in left TLE, 2) there is a significant relationship between adequacy of language function and several aspects of verbal learning and memory ability in both left and right temporal lobe groups, and 3) clinical assessment and theoretical models of memory need to consider these relationships.