Innovations In Clinical Neuroscience

JAN-FEB 2017

A peer-reviewed, evidence-based journal for clinicians in the field of neuroscience

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Page 33 of 63

Innovations in CLINICAL NEUROSCIENCE [ V O L U M E 1 4 , N U M B E R 1 – 2 , J A N U A R Y – F E B R U A R Y 2 0 1 7 ] 34 functional capacity assessment detects f airly substantial deficits in individuals with MCI and that the performance of these populations separates from both more severe AD on the one hand and healthy older individuals on the other. P erformance-based functional assessment, despite being an alternative form of cognitive assessment, is appealing because of its immediate clinical relevance as a direct measure of functioning and not a distal measure such as a word list recall. The FDA has endorsed the use of these measures as a functional co-primary in treatment trials aimed at cognition in severe mental illness and has verbally expressed interest in these in early AD as well. A critical factor here is the sensitivity of the functional assessment measure employed. Detection of functional impairment in cognitively normal individuals with a biomarker for AD will require instruments sensitive to very subtle functional changes. Global informant report rating measures commonly used to characterize functional decline in late MCI and AD type dementia are unlikely to detect presumably very subtle functional changes in cognitively normal persons with an amyloid biomarker. 34 In order to maximize sensitivity, such new assessment measures should incorporate the following features: 3 4 1. Assess cognitively complex functional abilities relevant to independent living and sensitive to early decline 2. Assess functional ability using an interval-scaled, direct-performance measure that evaluates performance variables in a highly detailed and granular manner 3. Include time limitations for performance items in order to enhance the item's cognitive complexity without changing basic task demands 4. In addition to performance items, include completion time variables in order to capture subtle processing speed changes. As noted above, financial capacity specifically represents an IADL critical to independent living. In this vein, the University of Alabama at Birmingham group has recently developed a new f unctional assessment measure, the Financial Capacity Instrument—Short Form (FCI-SF; 40 ), which evaluates performance on tasks of monetary calculation, financial conceptual k nowledge, use of a checkbook/register, and use of a bank statement and also includes time to completion variables. The FCI-SF takes 15 minutes or less to administer to cognitively normal older adults, and fulfills the four measure characteristics above for functional assessment measures in preclinical AD. A fuller description of the development and psychometric characteristics of the FCI-SF can be found elsewhere. 40–42 In promising initial field testing, the performance and timing variables of the FCI-SF have proven sensitive to early financial skill declines in cognitively normal older adults in the Mayo Clinic Study of Aging who are amyloid positive based on C11 PiB positron emission tomography (PET) neuroimaging. 4 0–42 Similar promise may hold for broader assessments like the UCSD Performance-Based Skills Assessment. 43 Several studies using the UPSA have shown that performance on tests that measure the ability to perform everyday functional skills are impaired in patients with MCI compared to healthy controls, with MCI patients performing better than patients with AD. Goldberg et al 4 4 used the UPSA to compare healthy individuals, people with amnestic MCI, and AD patients and found that patients with amnestic MCI had substantial effect size (d=0.86) impairments in UPSA performance compared to healthy individuals. These MCI patients were not rated as manifesting any impairment on the ADCS-ADL scale compared to healthy controls (HC), while both groups were less impaired than the AD patients. In the sample as a whole (MCI, AD, HC) the correlation between the ADCS-ADL subscale and the UPSA was substantial (Spearman rho=0.63). Thus, the UPSA was sensitive to impairments in MCI patients not detected by the ADCS-ADL scale and manifested considerable evidence of validly identifying the correlates of real-world functional deficits. Further, an abbreviated version of the UPSA was developed for use in MCI, 45 which also was found to have e xcellent discriminant validity and a very brief (7–10 minute) administration time. Given the correlations previously published between UPSA scores and cognitive test performance in healthy c ontrols, 4 6 i t would not be surprising to see impaired functional or performance- based skills in individuals whose impairments do not yet meet the criteria for MCI. A recent development in the assessment of functional capacity is that of computerized assessment strategies. Using both virtual reality and video technology, tasks have been developed that realistically simulate everyday functional tasks. Some of these tasks have demonstrated sensitivity to age related differences in healthy people, substantial correlations with cognitive test performance, and substantial separation of the performance of healthy people from various impaired populations. 4 7 Many real life functional tasks themselves are now performed on a computer, such as bill paying, information-seeking, and purchasing, rendering the task of the assessment creator to creating simulations that are particularly honed and relevant. Computerized tasks are also important because paper and pencil functional capacity measures, including the FCI-SF and the UPSA, have subtests that require performance of everyday tasks that may be becoming outdated, including writing paper checks and making paper check deposits. Computerized measures are more rapidly updatable with the latest technological innovations and have been shown for years to be sensitive to variation in performance in samples of healthy older community residents. 48 For example, in the study by Atkins et al , 48 a computerized assessment procedure called the Virtual Reality Functional Capacity Assessment (VRFCAT) was administered to 44 healthy younger adults (aged 18–30) and 41 healthy older adults ( aged 55– 70). The VRFCAT is a computer-based virtual-reality measure of functional capacity that relies on a realistic simulated environment to recreate routine IADLs, with a total of 12 different demands organized into a sequence that

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