Pitfall Intention Explanation Task with Clue Questions (Pitfall task): assessment of comprehending other people's behavioral intentions in Alzheimer's disease.

BACKGROUND

In Alzheimer's disease (AD) patients, deficits in contextual understanding and intentions/beliefs of other people (theory of mind; ToM) cause communication problems between patients and caregivers. To evaluate deficits of contextual understanding/ToM, we developed the Pitfall Intention Explanation Task with Clue Questions (Pitfall task).

METHODS

We recruited 26 healthy older adults in clinical dementia rating (CDR) 0, and 62 outpatients: 12 with amnestic mild cognitive impairment (aMCI) in CDR 0.5; 36 mild AD in CDR 1; and 14 moderate AD in CDR 2. The Pitfall task consists of a single-frame cartoon that shows a character's intention and seven serial questions that provide clues for contextual understanding/ToM.

RESULTS

The total score (0-7) was decreased with progression of AD (CDR 0, 5.4 ± 2.6; CDR 0.5, 3.7 ± 2.7; CDR 1, 1.9 ± 3.1; CDR 2, 0.0 ± 0.0; respectively). In CDR 0, two-third of the participants responded correctly without clue questions. In CDR 0.5, one-third of the participants responded correctly without clue questions, and half of them understood with the help of the clue questions. In CDR 1, one-fourth of the participants responded correctly without clue questions, and the clue questions did not increase the correct response. In CDR 2, none responded correctly. Additionally, the Pitfall task provided the chance for patients' families to observe patients' responses.

CONCLUSION

Contextual understanding/ToM, a kind of social cognition, was impaired with progression of AD. The Pitfall task evaluates the function quickly with low burden for memory function, and may provide helpful clues for caregivers to achieve good communication with AD patients.