Lower-Extremity Function in Cognitively Healthy Aging, Mild Cognitive Impairment, and Alzheimer's Disease

Abstract

Objective To examine differences in lower-extremity function in cognitive healthy older persons, older persons with mild cognitive impairment (MCI), and older persons with Alzheimer’s disease (AD). Design Descriptive study. Setting University Alzheimer’s disease clinical and research program. Participants Older persons (N=66) were studied (mean age, 76.7y); 22 were cognitively normal, 22 were diagnosed with probable MCI, 22 were diagnosed with probable AD. Interventions Not applicable. Main Outcome Measures Lower-extremity function was assessed by the four-meter walk test (4MWT), Timed Up & Go (TUG) test, and sit-to-stand (STS) test. Results Analysis of variance, adjusting for covariates, revealed that performance on the 4MWT was significantly lower in the MCI and AD groups as compared with controls. TUG test performance was worse in the AD group compared with controls. No significant group differences were found for STS performance. Conclusions These results suggest an association between cognitive impairment and lower-limb function in older persons Walking speed could be evaluated for its possible utility in screening older persons at risk for cognitive impairment and falls.

Cognitive Impairment Is Reflected by an Increased Difference between Real and Imagined Timed Up and Go Test Performance

“…This, too, is consistent with other studies, which also did not report any significant slowing in TUG times related to cognitive status [13,36]. Referring to Mirelman et al [13], one could suggest that the gait disturbances related to executive dysfunction are shown in subtasks of gait but do not impair gait speed.…”

Dual task-related gait changes in patients with mild cognitive impairment

“…High CoV values have been related to impaired executive function (Allali et al, 2007). WS is a measure of gait stability and the risk of falls (Abellan van Kan et al, 2009) and has previously been used as a functional measure to assess the presence of MCI (Eggermont et al, 2010;Pettersson et al, 2007). Finally, higher DS values have been related to unsteadiness (Benedetti et al, 2012).…”

“…However, patients with MCI are at a high risk of developing Alzheimer's dementia (Aggarwal et al, 2006). Besides cognitive decline, MCI patients may manifest early motor and gait dysfunction (Verghese et al, 2008;Eggermont et al, 2010). Gait impairment entails a high risk of falls and institutionalization, as has been shown both in healthy elderly individuals and in patients with dementia (Sheridan and Hausdorff, 2007).…”

Preserving Cognition, Quality of Life, Physical Health and Functional Ability in Alzheimer's Disease: The Effect of Physical Exercise (ADEX Trial): Rationale and Design

“…The 6-min Astrand Cycle Ergometer test (Monark Ergomedic 839E; Monark Exercise AB, Sweden) estimates the maximal oxygen uptake based on age, body weight and the workload, and average heart rate during the last minute of the test [51]. Functional performance tests include the Timed Up and Go (TUG) test [52], the 30-second chair stand test (the number of full stands in 30 s with arms folded across the chest from a standard chair) [32], the timed 10-min walk test (usual speed) [53] and the timed 400-meter walk test (fast speed) [54]. In addition, dual task performance is measured with the timed 10-min walk test combined with naming the months backwards and counting backwards from 50, respectively [53].…”

“…In general, most studies are on nursing home residents with AD and methodological issues restrict the conclusions which may be drawn from these studies [26,27]. In nursing home residents with AD or unspecified dementia, some intervention studies show a positive effect of physical exercise on cognition [28,29], whereas others show no effect [30,31,32]. In home-dwelling patients with AD, cognition has been the primary outcome in only one small study [33], which showed a positive effect of low-intensity physical exercise on tests of global cognition.…”