Cognitive Correlates of Impaired Testamentary Capacity in Alzheimer's Dementia.

BACKGROUND: Testamentary capacity (TC) is a legal construct about the ability to make or change a will. Although studies of financial and medical capacities have noted a strong association between capacity and cognition, no study has examined the cognitive correlates of TC in Alzheimer's disease (ad). METHODS: Study participants were 22 cognitively healthy controls and 20 persons with mild to moderate ad who were administered a neuropsychological battery and the Testamentary Capacity Instrument (TCI), a new performance-based measure of TC. Both TCI Element and TCI Total scores were calculated. TCI Total scores were calculated for the purposes of expanding correlational analyses (i.e., Pearson's product-moment) and are not intended for forensic TC evaluations. Final predictors were identified using linear and logistic regression modeling. RESULTS: All ad participants but one obtained TCI Totals that fell >2.5 standard deviations below the control group mean. Initial cognitive correlates of TCI performance were measures of general cognition, language, verbal memory, executive function, and processing speed. The four cognitive variables showing the highest t values and correlating with TCI Total score > 0.7 were entered into logistic and linear regression models. Final predictor models consisted of measures of verbal memory, executive function, and semantic knowledge and demonstrated shared variance of 0.71 (linear) and 0.82 (logistic). CONCLUSIONS: A diagnosis of ad dementia is associated with clinical impairment in TC and associated cognitive abilities and indicates that a legal assessment of TC is warranted. Second, the results offer insight into the cognitive basis of TC in persons with Alzheimer's dementia.

Assessment of Testamentary Capacity in Older Adults: Description and Initial Validation of a Standardized Interview Instrument.

OBJECTIVE: Testamentary capacity (TC) is a legal construct, which concerns a person's mental capacity to make or amend a will. Although expert clinicians are frequently asked to assess TC in forensic settings, there are few instruments and little empirical research to inform and guide their assessments. The present study describes the development and psychometric properties of a standardized assessment measure of TC (Testamentary Capacity Instrument-TCI), and investigates its reliability and validity. METHODS: The TCI is an interview-based, psychometric measure, which assesses a testator's knowledge of four conceptual elements, which together comprise the legal basis for TC in the Anglo-American legal system: (1) what a will is, (2) nature and extent of assets/property, (3) possible heirs/claimants to property, and (4) plan to distribute assets to heirs after death. Cronbach's alpha and percentage exact agreement were used to examine TCI element reliabilities. Using independent samples t-tests, MANOVA and MANCOVA, we investigated validity by comparing TCI element performance of cognitively intact older adults (n = 22) and older adults with ad dementia (n = 20). RESULTS: The TCI elements showed good internal consistency and good inter-rater reliability. The ad group performed significantly below the control group on all four TCI elements, with effect sizes exceeding 1.2, suggesting that the TCI has content and construct validity. CONCLUSIONS: Relative to cognitively intact older adults, older adults with ad dementia showed significant impairment on all four TCI conceptual elements. The TCI has promise as a standardized quantitative measure of TC to support clinical assessment of TC in forensic settings.

WAIS-IV subtest covariance structure: conceptual and statistical considerations.

D. Wechsler (2008b) reported confirmatory factor analyses (CFAs) with standardization data (ages 16-69 years) for 10 core and 5 supplemental subtests from the Wechsler Adult Intelligence Scale-Fourth Edition (WAIS-IV). Analyses of the 15 subtests supported 4 hypothesized oblique factors (Verbal Comprehension, Working Memory, Perceptual Reasoning, and Processing Speed) but also revealed unexplained covariance between Block Design and Visual Puzzles (Perceptual Reasoning subtests). That covariance was not included in the final models. Instead, a path was added from Working Memory to Figure Weights (Perceptual Reasoning subtest) to improve fit and achieve a desired factor pattern. The present research with the same data (N = 1,800) showed that the path from Working Memory to Figure Weights increases the association between Working Memory and Matrix Reasoning. Specifying both paths improves model fit and largely eliminates unexplained covariance between Block Design and Visual Puzzles but with the undesirable consequence that Figure Weights and Matrix Reasoning are equally determined by Perceptual Reasoning and Working Memory. An alternative 4-factor model was proposed that explained theory-implied covariance between Block Design and Visual Puzzles and between Arithmetic and Figure Weights while maintaining compatibility with WAIS-IV Index structure. The proposed model compared favorably with a 5-factor model based on Cattell-Horn-Carroll theory. The present findings emphasize that covariance model comparisons should involve considerations of conceptual coherence and theoretical adherence in addition to statistical fit.