JMIR Publications

ABSTRACT

Background:

Conventional methods of functional assessment include subjective self/informant- report, which may be biased by personal characteristics, cognitive abilities, and lack of standardization (e.g., influenced by idiosyncratic task demands). Traditional performance-based assessments offer some advantages over self/informant reports, but they are time consuming to administer and score.

Objective:

To evaluate the validity and reliability of the Virtual Kitchen Challenge -Version 2 (VKC-2), an objective, standardized, and highly efficient alternative to current functional assessments for older adults across the spectrum of cognitive aging, from preclinical to mild dementia.

Methods:

236 community-dwelling diverse older adults completed a comprehensive neuropsychological evaluation to classify their cognitive abilities as healthy, mild cognitive impairment or mild dementia, after adjustment of demographic variables (age, education, sex, estimated IQ). Participants were administered the VKC-2, which required completion of two everyday tasks (breakfast, lunch) in a virtual kitchen using a touch-screen interface to select objects and sequence steps. Automated scoring reflected completion time and performance efficiency (e.g., number of screen interactions, % time spent off screen, interactions with distractor objects). Participants also completed the VKC-2 tasks using real objects (Real Kitchen) and questionnaires of everyday function. Informants for 219 participants completed questionnaires regarding everyday function. A subsample of participants (n = 143) performed the VKC-2 again in a second session 4-6 weeks after the baseline for retest analyses. Analyses evaluated construct and convergent validity and retest and internal reliability of VKC-2 automated scores.

Results:

Construct validity was supported by ANCOVA results showing participants with healthy cognition obtained significantly better VKC-2 scores than participants with cognitive impairment (all ps < .001), even after controlling for demographics and general computer visuomotor dexterity. Convergent validity was supported by significant correlations between VKC-2 scores and performance on the Real Kitchen (r values = -.58 to .64, ps < .001), conventional cognitive test scores (r values = -.50 to -.22, ps < .001), and to self and informant questionnaires evaluating everyday function (r values = .25 to .43, ps < .001). Retest reliability was strong as evidenced by high intraclass correlations between VKC-2 scores across the two timepoints (κ = 0.27, p < .001). Reliability improved in analyses including only participants who reported no change in cognitive status between time 1 and time 2 (n=123). Spearman-Brown correlations showed acceptable to good internal consistency between the VKC-2 tasks (breakfast, lunch) for all scores (.77 to .81) supporting the use of total scores.

Conclusions:

The VKC-2 is an efficient, valid, and sensitive measure of everyday function for diverse older adults that may be used for large scale longitudinal studies, clinical trials, and clinical assessments. The VKC-2 holds promise to improve the status quo of functional assessment in aging particularly when informants are unavailable or unreliable.