Action perception predicts action performance

Abstract

Everyday action impairments often are observed in demented older adults, and they are common potential barriers to functional independence. We evaluated whether the ability to segment and efficiently encode activities is related to the ability to execute activities. Further, we evaluated whether brain regions important for segmentation also were important for action performance. Cognitively healthy older adults and those with very mild or mild dementia of the Alzheimer's type watched and segmented movies of everyday activities and then completed the Naturalistic Action Test. Structural MRI was used to measure volume in the dorsolateral prefrontal cortex (DLPFC), medial temporal lobes (MTL), posterior cortex, and anterior cingulate cortex (ACC). Dementia status and the ability to segment everyday activities strongly predicted naturalistic action performance, and MTL volume largely accounted for this relationship. In addition, the current results supported the Omission-Commission Model: Different cognitive and neurological mechanisms predicted different types of action error. Segmentation, dementia severity, and MTL volume predicted everyday omission errors, DLPFC volume predicted commission errors, and ACC volume predicted action additions. These findings suggest that event segmentation may be critical for effective action production, and that the segmentation and production of activities may recruit the same event representation system.

Keywords: Action performance; Dementia; MTL volume; Perception; Segmentation.

Fig. 1

Stills taken from each of the three experimental movies: making breakfast, decorating for a party, and planting window boxes. Durations were 329 s, 376 s, and 354 s.

Fig. 2

Schematic for how the objects were arranged for the NAT Task 3.

Fig. 3

Segmentation agreement scores by CDR group. Error bars are standard errors of the mean.

Fig. 4

NAT scores ranging from 0–6 by CDR group. Error bars are standard errors of the mean.

Fig. 5

Mean number of errors (omission, commissions, and action additions) committed on the NAT. Error bars are standard errors of the mean.

Fig. 6

Mean proportion of each error type from total errors. Error bars are standard errors of the mean.

Fig. 7

Scatter plot for the relationship between segmentation agreement and NAT scores.

Fig. 8

Scatter plots for the relationships between segmentation agreement and (a) omission errors, (b) commission errors, and (c) action additions.