A componential analysis of proverb interpretation in patients with frontal lobe epilepsy and temporal lobe epilepsy: relationships with disease-related factors.

The ability to interpret nonliteral, metaphoric language was explored in patients with frontal lobe epilepsy (FLE) and temporal lobe epilepsy (TLE), and matched control participants, to determine (1) if patients with FLE were impaired in their interpretations relative to those with TLE and controls, and (2) if disease-related variables (e.g., age of seizure onset) predicted performances in either patient group. A total of 22 patients with FLE, 20 patients with TLE, and 23 controls were administered a test of proverb interpretation to assess their ability to grasp the abstract meaning of nonliteral language. Participants were presented with a series of proverbs and asked to provide an oral interpretation of each. Responses to each proverb were scored according to their accuracy and level of abstractness. Patients with FLE, but not TLE, were impaired relative to controls in their overall interpretation of proverbs. However, a subgroup analysis revealed that only patients with left FLE showed impaired interpretation accuracy relative to the other groups, whereas patients with both left FLE and left TLE showed impaired abstraction. Patients with FLE were also impaired when they were asked to select the best interpretation of the proverb from response alternatives. In patients with FLE, only a left-sided seizure focus was associated with poorer performance. In patients with TLE, both an early age of onset and a left-sided seizure focus predicted poorer performance. Overall, FLE patients exhibit greater impairment than TLE patients in interpreting proverbs. However, the nature and disease-specific correlates of impaired performances in proverb interpretation differ between the groups.