Cognitive functions in the informed consent evaluation process: a pilot study.

Assessment of capacity to give informed consent in the general hospital setting usually rests on a clinical judgment made of a patient's understanding and appreciation of his or her illness, a process limited by its subjective nature, interexaminer variability, and relative deficiency of quantitative instruments available to provide collateral information. Inasmuch as identification of associated variables could strengthen this process, this study examines the association of cognitive functions to the capacity to give informed consent. Over a one-year period, 65 patients were evaluated independent of medical or psychiatric diagnoses. The study population consisted of medical and neurology inpatients seen for neuropsychiatric evaluation. All evaluations included assessment of capacity to give informed consent as it related to the reason for the admission to the hospital, followed by administration of the Hopkins Competency Assessment Test, the Mini-Mental Status Examination, the Trail-Making Test, Parts A and B, and the Executive Interview. Of 65 patients, 34 were excluded based on preset criteria. The remaining patients were assigned to either a "competent" or "noncompetent" group based on clinical evaluation. Number of patients, gender, and handedness distributions between groups were similar. The groups did not differ significantly in terms of age or education. Significant between-group differences were found on an empirical measure of competency, a general mental state measure, and on measures of attentional and executive cognitive functions. An analysis of classification rates indicated that a measure of executive cognitive functioning (Executive Interview) had the best sensitivity and specificity in correctly classifying competent and noncompetent patients. The results of this study support the association between the capacity to give informed consent in the hospital setting and measures of cognitive functioning, suggesting that utilization of cognitive function measures may strengthen the competency assessment process.