Relationship between 18F-Flutemetamol uptake and RBANS performance in non-demented community-dwelling older adults.

OBJECTIVE: The Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) has been used extensively for clinical care and in research for patients with mild cognitive impairment and Alzheimer's disease (AD); however, relatively few studies have evaluated the relationship between RBANS performance and AD imaging biomarkers. The purpose of the current study was to evaluate the association between a relatively new amyloid positron emission tomography imaging biomarker and performance on the RBANS. METHODS: Twenty-seven nondemented community-dwelling adults over the age of 65 underwent 18F-Flutemetamol amyloid- positron emission tomography imaging, along with cognitive testing using the RBANS and select behavioral measures. Partial correlation coefficients were used to identify relationships between the imaging and behavioral markers. RESULTS: After controlling for age and education, amyloid deposition and RBANS Indexes of Immediate Memory, Delayed Memory, and Total Scale score were significantly correlated (p's < .001, r's = -.73 to -.77, d's = 2.13-2.39), with greater amyloid burden being associated with lower RBANS scores. The Delayed Memory Index was particularly highly associated with 18F-Flutemetamol binding (r2 = .59, p < .001, d = 2.39). Neither 18F-Flutemetamol binding nor RBANS performance was significantly correlated with levels of depression, subjective cognitive difficulties, or premorbid intellect. CONCLUSIONS: Because of the limited use of amyloid imaging in clinical settings due to high cost and lack of reimbursement, these findings suggest that in particular RBANS Delayed Memory Index may be a cost-efficient tool to identify early signs of AD pathology, and its use may enlighten clinical decision-making regarding potential progression to dementia due to AD.

Amyloid Positivity Using [18F]Flutemetamol-PET and Cognitive Deficits in Nondemented Community-Dwelling Older Adults.

Little research exists examining the relationship between beta-amyloid neuritic plaque density via [18F]flutemetamol binding and cognition; consequently, the purpose of the current study was to compare cognitive performances among individuals having either increased amyloid deposition (Flute+) or minimal amyloid deposition (Flute-). Twenty-seven nondemented community-dwelling adults over the age of 65 underwent [18F]flutemetamol amyloid-positron emission tomography imaging, along with cognitive testing using the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) and select behavioral measures. Analysis of variance was used to identify the differences among the cognitive and behavioral measures between Flute+/Flute- groups. Flute+ participants performed significantly worse than Flute- participants on RBANS indexes of immediate memory, language, delayed memory, and total scale score, but no significant group differences in the endorsed level of depression or subjective report of cognitive difficulties were observed. Although these results are preliminary, [18F]flutemetamol accurately tracks cognition in a nondemented elderly sample, which may allow for better prediction of cognitive decline in late life.

Amyloid deposition and cognition in older adults: the effects of premorbid intellect.

Although amyloid deposition remains a marker of the development of Alzheimer's disease, results linking amyloid and cognition have been equivocal. Twenty-five community-dwelling non-demented older adults were examined with (18)F-flutemetamol, an amyloid imaging agent, and a cognitive battery, including an estimate of premorbid intellect and the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). In the first model, (18)F-flutemetamol uptake significantly correlated with the Delayed Memory Index of the RBANS (r = -.51, p = .02) and premorbid intellect (r = .43, p = .03). In the second model, the relationship between (18)F-flutemetamol and cognition was notably stronger when controlling for premorbid intellect (e.g., three of the five RBANS Indexes and its Total score significantly correlated with (18)F-flutemetamol, r's = -.41 to -.58). Associations were found between amyloid-binding (18)F-flutemetamol and cognitive functioning in non-demented older adults. These associations were greatest with delayed memory and stronger when premorbid intellect was considered, suggesting that cognitive reserve partly compensates for the symptomatic expression of amyloid pathology in community-dwelling elderly.