Dual-Task Performance: Influence of Frailty, Level of Physical Activity, and Cognition.

BACKGROUND AND PURPOSE: Cognition and level of physical activity have been associated with frailty syndrome. The development of tools that assess deficits related to physical and cognitive frailties simultaneously are of common interest. However, little is known about how much these aspects influence the performance of dual-task tests. Our aims were (a) to verify the influence of frailty syndrome and objectively measured physical activity and cognition on the Timed Up and Go (TUG) test and Timed Up and Go associated with dual-task (TUG-DT) performances; and (b) to compare TUG and TUG-DT performances between older adults who develop frailty syndrome. METHODS: Sixty-four community-dwelling older adults were divided into frail, prefrail, and nonfrail groups, according to frailty phenotype. Assessments included anamnesis, screening of frailty syndrome, cognitive assessment (Addenbrooke's Cognitive Examination), placement of a triaxial accelerometer to assess level of physical activity, and TUG and TUG-DT (TUG associated with a motor-cognitive task of calling a phone number) performances. After 7 days, the accelerometer was removed. A multiple linear regression was applied to identify which independent variables could explain performances in the TUG and TUG-DT. Subsequently, the analysis of covariance test, adjusted for age, cognition, and level of physical activity covariates, was used to compare test performances. RESULTS: There were no differences in cognition between groups. Significant differences in the level of physical activity were found in the frail group. Compared with the frail group, the nonfrail group required less time and fewer steps to complete the TUG. Regarding the TUG-DT, cognition and age influenced the time spent and number of steps, respectively; however, no differences were found between groups. CONCLUSIONS: Frail older adults presented worse performance in the TUG when compared with nonfrail older adults. The dual-task test does not differentiate older adults with frailty syndrome, regardless of cognitive performance.

ADAM10 gene expression in the blood cells of Alzheimer's disease patients and mild cognitive impairment subjects.

ADAM10 is a potential biomarker for Alzheimer's disease (AD). ADAM10 protein levels are reduced in platelets of AD patients. The aim was to verify the total blood and platelet ADAM10 gene expression in AD patients and to compare with mild cognitive impairment (MCI) and healthy subjects. No significant differences in ADAM10 gene expression were observed. Therefore, the decrease of ADAM10 protein in platelets of AD patients is not caused by a reduction in ADAM10 mRNA. Further studies must be performed to investigate other pathways in the down regulation of ADAM10 protein.