Toward a neurologic model of competency: Cognitive predictors ofcapacity to consent in Alzheimer's disease using three differentlegal standards
D.C. Marson
Bok Engelsk 1996
| Utgitt | 1996
|
|---|---|
| Omfang | Side 666- 672
|
| Opplysninger | Objective: To identify cognitive predictors of competency performanceand status in Alzheimer's disease (AD) using three differentiallystringent legal standards for capacity to consent. Design: Univariateand multivariate analyses of independent neuropsychological testmeasures with three dependent measures of competency to consent totreatment. Setting: University medical center. Subjects: 15 normalolder controls and 29 patients with probable AD (15 mild and 14moderate). Main Outcome Measures: Subjects were administered abattery of neuropsychological measures theoretically linked tocompetency function, as well as two clinical vignettes testingcapacity to consent to medical treatment under five legal standards(LSs). The present study focused on three differentially stringentLSs: the capacity simply to ''evidence a treatment of choice'' (LS1),which is a minimal standard; the capacity to ''appreciate theconsequences'' of a treatment choice (LS3), a moderately stringentstandard; and the capacity to ''understand the treatment situationand choices'' (LS5), the most stringent standard. Control subject andAD patient neuropsychological test scores were correlated with scoreson the three LSs. The resulting univariate correlates were thenanalyzed using stepwise regression and discriminant function toidentify key multivariate predictors of competency performance andstatus under each LS. Results: No neuropsychological measurespredicted control group performance on the LSs. For the AD group, ameasure of simple auditory comprehension predicted LS1 performance(r(2) = 0.44, p < 0.0001), a word fluency measure predicted LS3performance (r(2) = 0.58, p < 0.0001), and measures ofconceptualization and confrontation naming together predicted LS5performance (r(2) = 0.81, p < 0.0001). Under discriminant functionanalysis, confrontation naming was the best single predictor of LS1competency status for all subjects, correctly classifying 96% ofcases (42/44). Measures of visuomotor tracking and confrontationnaming were the best single predictors, respectively, of competencystatus under LS3 (91% [39/43]) and LS5 (98% [43/44]). Conclusions:Multiple cognitive functions are associated with loss of competencyin AD. Deficits in conceptualization, semantic memory, and probablyverbal recall are associated with the declining capacity of mild ADpatients to understand a treatment situation and choices (LS5);executive dysfunction with the declining capacity of mild to moderateAD patients to identify the consequences of a treatment choice (LS3);and receptive aphasia and severe dysnomia with the declining capacityof advanced AD patients to evidence a simple treatment choice (LS1).The results offer insight into the relationship between differentlegal thresholds of competency and the progressive cognitive changescharacteristic of AD, and represent an initial step toward aneurologic model of competency.
|
| Emner |
