The utility of the Montreal Cognitive Assessment as a mental capacity assessment tool for patients with a learning disability

Abstract

Accessible summary Accurate assessment of a patient's mental capacity is important, yet out of the clinical assessments currently available, there does not appear to be sufficient accessible tools suitable for people with a learning disability. Incorrect assumptions are often made regarding the capacity of patients who have learning disabilities to make decisions about important aspects of their life. This preliminary study investigated whether or not it was possible to adapt a well‐known assessment of cognitive impairment (The Montreal Cognitive Assessment) and use this as a tool to determine capacity in patients with a learning disability. Abstract Objective: To determine the psychometric properties of the Montreal Cognitive Assessment (MoCA) in patients with a learning disability and examine it's utility for conducting mental capacity assessment.Method: This study was a cross‐sectional, instrument validation study in an inpatient hospital setting, located in the East of England. The sample consisted of two groups: (i) 31 consecutively admitted hospital patients and (ii) 10 multidisciplinary team members who served as a comparison group. The MoCA, a 12‐item screen for mild cognitive impairment and the Dysexecutive Questionnaire (DEX), were used in this study. Item analysis was conducted by comparing item endorsement for all participants that had a learning disability utilising Difficulty and Discrimination Indices for each item on the MoCA. We examined the internal consistency of a revised scale derived from item analysis and used a one‐way ANOVA to determine concurrent validity by comparing scores between two patient subgroups and the comparison group.Results: A 7‐item scale, ‘MoCA‐LD’ (alpha coefficient = 0.82) emerged from item analysis. A statistically significant negative correlation was observed between MoCA‐LD and DEX (Pearson correlation = −0.66, P < 0.01). As expected, participants in the borderline category scored higher on MoCA‐LD than those with mild learning disability, as did those with no learning disability (P < 0.001).Conclusion: The MoCA‐LD has the potential to be a useful tool for mental capacity assessment in patients with a learning disability.

The predictive validity of the MoCA‐LD for assessing mental capacity in adults with intellectual disabilities

“…Good internal consistency (α = 0.78) has also been confirmed when using the test for people with intellectual disabilities (Edge et al, 2016 (Vogel, Banks, Cummings, & Miller, 2015).…”

“…Good internal consistency ( α = 0.83) and test–retest reliability ( r = 0.92, p < 0.001) have been confirmed with a variety of different populations including individuals with Alzheimer's and mild cognitive impairment (Nasreddine et al, ). Good internal consistency ( α = 0.78) has also been confirmed when using the test for people with intellectual disabilities (Edge et al, ). Construct validity is supported by significant correlations with performance on a comprehensive test battery comprising a number of different neuropsychological measures: items from the Brief Visuospatial Memory Test; Hopkins Verbal Learning Test; Wechsler Memory Scale; Delis–Kaplan Executive Function System; Boston Naming Test; and Wechsler Adult Intelligence Scale (Vogel, Banks, Cummings, & Miller, ).…”

“…Overall cognitive ability was estimated using the eight items that best discriminate between high-and low-performing individuals with intellectual disabilities. The good psychometric properties of this more specialized MoCA-Learning Disability (MoCA-LD) have been confirmed for the population of interest (Edge et al, 2016). Levels of ability in the four specific cognitive functions were estimated by summing scores for the MoCA items that share high factor loadings with standard neuropsychological measures (Vogel et al, 2015).…”

“…When applying this theoretical framework to mental capacity assessment, if a person were unable to engage a Type Two process, this would support a lack of mental capacity. The four cognitive functions associated with a Type Two process certainly align with the conceptual considerations specified in the MCA (Edge, Oyefeso, Evans, & Evans, ; Wilner et al, ), but researchers have yet to test empirically for links between these functions and “real life” mental capacity assessment outcomes when someone has an intellectual disability.…”

“…The four cognitive functions associated with a Type Two process certainly align with the conceptual considerations specified in the MCA (Edge, Oyefeso, Evans, & Evans, 2016;Wilner et al, 2010), but researchers have yet to test empirically for links between these functions and "real life" mental capacity assessment outcomes when someone has an intellectual disability.…”