The impact of semantic dementia on everyday actions : evidence from an ecological study

In theory, semantic memory may trigger and support the execution of everyday activities. This study explored this question by comparing three patients with semantic dementia to 40 normal controls performing different everyday activities. Participants were tested in their home using the Instrumental Activities of Daily Living Profile, an ecological measure of everyday functioning. Participants were informed that they had unknowingly invited two guests for lunch and should prepare accordingly. With these instructions, they dress to go outdoors, go to the grocery store, shop for food, prepare a hot meal, have the meal with the guests, and clean up after the meal. Performance was analyzed on the basis of four operations related to problem solving: formulate a goal, plan, execute, and verify attainment of the goal. Results indicate that compared to normal controls, two patients had significant difficulties and needed assistance with all operations of problem-solving, particularly while preparing a meal and cleaning up after the meal. One patient showed no difficulties despite severe semantic deficits. These results suggest that semantic deficits alone cannot explain the difficulties observed, but may contribute to some aspects of everyday actions such as those involved in everyday problem-solving