摘要
BACKGROUND Cognitive issues such as Alzheimer’s disease and other dementias confer a substantial negative impact.Problems relating to sensitivity,subjectivity,and inherent bias can limit the usefulness of many traditional methods of assessing cognitive impairment.AIM To determine cut-off scores for classification of cognitive impairment,and assess Cognivue®safety and efficacy in a large validation study.METHODS Adults(age 55-95 years)at risk for age-related cognitive decline or dementia were invited via posters and email to participate in two cohort studies conducted at various outpatient clinics and assisted-and independent-living facilities.In the cut-off score determination study(n=92),optimization analyses by positive percent agreement(PPA)and negative percent agreement(NPA),and by accuracy and error bias were conducted.In the clinical validation study(n=401),regression,rank linear regression,and factor analyses were conducted.Participants in the clinical validation study also completed other neuropsychological tests.RESULTS For the cut-off score determination study,92 participants completed St.Louis University Mental Status(SLUMS,reference standard)and Cognivue^®tests.Analyses showed that SLUMS cut-off scores of<21(impairment)and>26(no impairment)corresponded to Cognivue^®scores of 54.5(NPA=0.92;PPA=0.64)and 78.5(NPA=0.5;PPA=0.79),respectively.Therefore,conservatively,Cognivue^®scores of 55-64 corresponded to impairment,and 74-79 to no impairment.For the clinical validation study,401 participants completed≥1 testing session,and 358 completed 2 sessions 1-2 wk apart.Cognivue^®classification scores were validated,demonstrating good agreement with SLUMS scores(weightedκ0.57;95%CI:0.50-0.63).Reliability analyses showed similar scores across repeated testing for Cognivue^®(R2=0.81;r=0.90)and SLUMS(R2=0.67;r=0.82).Psychometric validity of Cognivue^®was demonstrated vs.traditional neuropsychological tests.Scores were most closely correlated with measures of verbal processing,manual dexterity/speed,visual contrast sensitivity,visuospatial/executive function,and speed/sequencing.CONCLUSION Cognivue^®scores≤50 avoid misclassification of impairment,and scores≥75 avoid misclassification of unimpairment.The validation study demonstrates good agreement between Cognivue^®and SLUMS;superior reliability;and good psychometric validity.
