Planning Ability After Frontal and Temporal Lobe Lesions in Humans: The Effects of Selection Equivocation and Working Memory Load

Twenty-one patients with unilateral frontal neurosurgical lesions (11 left and 10 right) and 38 patients with unilateral temporal lobectomies (19 left and 19 right) were compared to 44 normal control subjects in their performance on a computerised version of the Tower of Hanoi (TOH) test. In order to explore the effect of selection equivocation on performance, two types of problems were administered, determined by whetherthe two mainroutes to achieve the goal weresimilar or dissimilar in length. To explore the effectof working memory load, a task was administered that required the subject to repeat a sequence of Tower of Hanoi moves shown by the computer. For the frontal patients, those with right (RF), but not left (LF) lesions were impaired on TOH, but response equivocation had no effecton performance. The LF group, however, were impaired on the working memory task. Forthetemporal patients, only therightlesion group wereimpaired on TOH, but specifically on the dissimilar problems. This group were also i...