An ecological approach to planning dysfunction: Script execution

Planning, which concerns many activities in everyday life, is a two-stage p rocess. The first one predetermines a course of actions aimed at achieving some specific goals. It is founded on managerial knowledge or overlearned s equences of events and may be tested by script generation. The second stage entails monitoring and guiding the execution of the plan to a successful c onclusion. It must take into account environmental contingencies and may be tested by script execution. If the frontal lobes intervene not only in man agerial knowledge (Grafman, 1989) but also in binding the plan with context ual environment (Damasio, Tranel and Damasio, 1991; Shallice and Burgess, 1 991), script execution would be more sensitive than script generation to pl anning deficits. To test this hypothesis, script execution and script gener ation were compared in 11 patients with a dysexecutive syndrome and 10 matc hed controls, using three scripts of daily life activities: (1) 'shopping f or groceries'; (2) 'cooking'; (3) 'answering a letter and finding the way t o post the reply'. Two way ANOVAs showed more errors in execution than in g eneration, more errors in patients than in controls, and a greater differen ce between execution and generation in patients than in controls. Furthermo re, 'context neglect' and 'environmental adherence' were the two types of e rrors that best differentiated patients from controls. Finally, the total n umber of errors in execution correlated with the score on behavioral questi onnaires answered by occupational therapists. These results confirm our hyp othesis and suggest that script execution may be a valid ecological approac h to estimate the severity of deficits in daily life activities.