Petersen, Ronald C.

Abstract Background Objective cost estimates and source of cost differences are needed across the spectrum of cognition, including cognitively normal (CN), mild cognitive impairment (MCI), newly discovered dementia, and prevalent dementia. Methods Subjects were a subset of the Mayo Clinic Study of Aging stratified‐random sampling of Olmsted County, MN, residents aged 70 to 89 years. A neurologist reviewed provider‐linked medical records to identify prevalent dementia (review date = index). Remaining subjects were invited to participate in prospective clinical/neuropsychological assessments; participants were categorized as CN, MCI, or newly discovered dementia (assessment date = index). Costs for medical services/procedures 1‐year pre‐index (excluding indirect and long‐term care costs) were estimated using line‐item provider‐linked administrative data. We estimated contributions of care‐delivery site and comorbid conditions (including and excluding neuropsychiatric diagnoses) to between‐category cost differences. Results Annual mean medical costs for CN, MCI, newly discovered dementia, and prevalent dementia were $6042, $6784, $9431, $11,678, respectively. Hospital inpatient costs contributed 70% of total costs for prevalent dementia and accounted for differences between CN and both prevalent and newly discovered dementia. Ambulatory costs accounted for differences between CN and MCI. Age‐, sex‐, education‐adjusted differences reached significance for CN versus newly discovered and prevalent dementia and for MCI versus prevalent dementia. After considering all comorbid diagnoses, between‐category differences were reduced (e.g., prevalent dementia minus MCI (from $4842 to $3575); newly discovered dementia minus CN (from $3578 to $711)). Following the exclusion of neuropsychiatric diagnoses from comorbidity adjustment, between‐category differences tended to revert to greater differences. Conclusions Cost estimates did not differ significantly between CN and MCI. Substantial differences between MCI and prevalent dementia reflected high inpatient costs for dementia and appear partly related to co‐occurring mental disorders. Such comparisons can help inform models aimed at identifying where, when, and for which individuals proposed interventions might be cost‐effective.

AbstractIntroductionThe feasibility and validity of brief computerized cognitive batteries at the population‐level are unknown.MethodsNondemented participants (n = 1660, age 50–97 years) in the Mayo Clinic Study on Aging completed the computerized CogState battery and standard neuropsychological battery. The correlation between tests was examined and comparisons between CogState performance on the personal computer (PC) and iPad (n = 331), and in the clinic vs. at home (n = 194), were assessed.ResultsWe obtained valid data on greater than 97% of participants on each test. Correlations between the CogState and neuropsychological tests ranged from −0.462 to 0.531. Although absolute differences between the PC and iPad were small and participants preferred the iPad, performance on the PC was faster. Participants performed faster on Detection, One Card Learning, and One Back at home compared with the clinic.DiscussionThe computerized CogState battery, especially the iPad, was feasible, acceptable, and valid in the population.

It is recognized that individuals with mild cognitive impairment (MCI) already demonstrate difficulty in aspects of daily functioning, which predicts disease progression. This study examined the relationship between self‐ versus informant‐report of functional ability, and how those reports relate to objective disease measures across the disease spectrum (i.e. cognitively normal, MCI, Alzheimer's disease). A total of 1080 subjects with self‐ and/or informant‐rated Everyday Cognition questionnaires were included. Objective measures included cognitive functioning, structural brain atrophy, cerebrospinal fluid abnormalities, and a marker of amyloid deposition using positron emission tomography with [ 18 F]AV45 (florbetapir). Overall, informant‐report was consistently more associated with objective markers of disease than self‐report although self‐reported functional status may still have some utility in early disease.