Research consent capacity varies with executive function and memory in Parkinson's disease.

BACKGROUND: We examined the association between cognitive domains and research consent capacity in PD. Our hypothesis was that research consent capacity is best predicted by executive function. METHODS: A cohort of 90 PD patients and 30 healthy older adults were administered the MacArthur Competence Assessment Tool for Clinical Research, Dementia Rating Scale-2, and the MoCA. Experts classified patients as either "capable" or "not capable" of providing informed consent to participate in two clinical trials. RESULTS: MacArthur Competence Assessment Tool for Clinical Research Reasoning scores for both clinical trial types were most associated with executive functions and delayed recall. As scores on these domains improved, the odds of an expert rating of "capable of consent" increased. CONCLUSIONS: These results extend our previous findings by demonstrating that memory and executive abilities appear closely associated with capacity when evaluated using either a structured interview or expert judgment of that interview.

Untimed Design Fluency in Aging and Alzheimer's Disease: Psychometrics and Normative Data.

Design fluency tests, commonly used in both clinical and research contexts to evaluate nonverbal concept generation, have the potential to offer useful information in the differentiation of healthy versus pathological aging. Although normative data for older adults (OAs) are available for multiple timed versions of this test, similar data have been unavailable for a previously published untimed test, the Graphic Pattern Generation Test (GPG). Time constraints common to almost all of the available design fluency tests may cloud interpretation of higher-level executive abilities-for example, in individuals with slow processing speed. The current study examined the psychometric properties of the GPG and presents normative data in a sample of 167 healthy OAs and 110 individuals diagnosed with Alzheimer's disease (AD). Results suggest that a brief version of the GPG can be administered reliably and that this short form has high test-retest and interrater reliability. Number of perseverations was higher in individuals with AD as compared with OAs. A cutoff score of 4 or more perseverations showed a moderate degree of sensitivity (76%) and specificity (37%) in distinguishing individuals with AD and OAs. Finally, perseverations were associated with nonmemory indexes, thereby underscoring the nonverbal nature of this error in OAs and individuals with AD.

Cognitive correlates of metamemory in Alzheimer's disease.

OBJECTIVE: Metamemory, or knowledge of one's memory abilities, is often impaired in individuals with Alzheimer's disease (AD), although the basis of this metacognitive deficit has not been fully articulated. Behavioral and imaging studies have produced conflicting evidence regarding the extent to which specific cognitive domains (i.e., executive function; memory) and brain regions contribute to memory awareness. The primary aim of this study was to disentangle the cognitive correlates of metamemory in AD by examining the relatedness of objective metamemory performance to cognitive tasks grouped by domain (executive function or memory) as well as by preferential hemispheric reliance defined by task modality (verbal or nonverbal). METHOD: Eighty-nine participants with mild AD recruited at Columbia University Medical Center and the University of Pennsylvania underwent objective metamemory and cognitive testing. Partial correlations were used to assess the relationship between metamemory and four cognitive variables, adjusted for recruitment site. RESULTS: The significant correlates of metamemory included nonverbal fluency (r = .27, p = .02) and nonverbal memory (r = .24, p = .04). CONCLUSIONS: Our findings suggest that objectively measured metamemory in a large sample of individuals with mild AD is selectively related to a set of interdomain nonverbal tasks. The association between metamemory and the nonverbal tasks may implicate a shared reliance on a right-sided cognitive network that spans frontal and temporal regions.

Cognitive impairment and PD patients' capacity to consent to research.

OBJECTIVE: To examine how cognitive impairment affects Parkinson disease (PD) patients' research consent capacity. METHODS: A cross-sectional study of 90 patients with PD, divided using Mattis Dementia Rating Scale-2 scores into 3 groups of 30 (normal, borderline, and impaired), and 30 neurologically normal older adults completed 2 capacity interviews (an early-phase randomized and controlled drug trial and a sham-controlled surgical implantation of genetic tissue) using the MacArthur Competence Assessment Tool for Clinical Research. Expert clinicians used the interviews to classify the patients as either capable or not capable of providing their own informed consent. These judgments were compared with performance on the Montreal Cognitive Assessment (MoCA) and the Mini-Mental State Examination (MMSE). RESULTS: Cognitively normal PD patients typically scored well on the capacity measures. In contrast, patients with impaired cognition were not capable of providing their own informed consent: 17% (5/30) on the drug trial and 3% (1/30) on the surgery trial were judged capable. Patients with borderline impairment showed adequate performance on measures of appreciation and reasoning, but impaired performance on understanding the drug trial compared with normal controls and normal PD patients, and on understanding the surgery trial compared with normal controls. Sixty-seven percent (20/30) on the drug trial and 57% (17/30) on the surgery trial were judged capable of consent. Receiver operating characteristic analyses showed that the MMSE and MoCA could detect the likelihood of impaired capacity, with the MoCA demonstrating greater sensitivity. CONCLUSIONS: PD patients with borderline cognitive impairment have impairments in their decisional capacity. The MoCA may be useful to identify the patients at risk of impaired capacity.