Dovepress Performance-based measures of balance have been described as attention-demanding physical tasks.4 The step test measures the speed of stepping movements during a dynamic standing task.33 It is a complex test that challenges both sta- bility and dynamic postural control. The test is performed at high speed, and it includes alternating movement patterns. To perform the task quickly, the subject must actively stop and reverse the direction of the moving leg, which places high demands on stability, limb coordination, and coordinated muscle activity in different muscle groups.Apart from demands on coordination of motor and postural control, the task also requires attention, planning, timing of movement sequences, and self-monitoring of motor behavior, which reflect executive function.52,58 We found an increase in the number of steps, ie, high movement speed, indicating good postural stability, to be associated with a lower risk of being cognitively impaired. Previous research has shown that slowing of rapid, alternating movements is associated with cognitive impairment;59 how- ever, to the best of our knowledge, no one has studied how the step test is associated with cognition. Using a composite measure score of balance, Wang et al43 found better balance to be associated with a lower risk of dementia, and the presence of poor balance to predict future cognitive decline in healthy older adults. We found poor performance of the OLS test to be related to an increased risk of being cognitively impaired, as have others.4,42 About half of our cases were not capable of balancing on one leg for 10 seconds and, compared to the controls, a considerably lower proportion was able to stand on one leg for $30 seconds. When using the ability to stand on one leg for up to 10 seconds as a time limit, Tabbarah et al4 found low OLS time to be related to a decline in cognitive performance. The three-word recall task of the MMSE has been found to be a good and valid measure of memory impairment to assess the domain of episodic memory, one of the earliest domains to decline in the course of cognitive impairment and incident dementia.14 The use of the subtest scores of the three-word recall item together with the total scores of the MMSE may increase the sensitivity of the MMSE in screening for mild cognitive impairment.60 The methodology of the three-word recall has been discussed previously.59 The three-word recall item has been shown to be sensitive to memory decline in older adults.24 However, variability in this test has been found among healthy elderly subjects as well,61 which may have led to misclassification of some of our subjects and, thus, affected the results. To reduce the effect of variability, adjustments were made for age, and prompting was used, as suggested by Chandler et al.24 We categorized the scores of delayed recall Clinical Interventions in Aging 2012:7 Cognitive impairment associated with slower physical test results into three groups, to study whether physical performance tests were able to differentiate cases from controls and intermediates. It was found that all the physical tests performed at high speed were able to separate cases from controls. WS, walking 2 × 15 m, and the step test also differentiated controls from intermediates. However, the lack of differentiation between cases and intermediates may indicate some degree of misclas- sification, or that moderate cognitive impairment also is related to physical performance. Our data indicate, from a clinical point of view, that tests of physical function that are performed at high speed, especially the step test and TUG, seem to be the most sensitive indicators of early memory decline. Physical tests performed at higher speeds may challenge the overall balance control system, necessitating attention and conscious control. The motor tests chosen may seem simple, but they require complex motor skills and psychomotor coordination, as well as the ability to sustain attention dur- ing a sequence of goal-directed movements. The anatomical network of motor control is interlinked with the network of higher-level cognitive processes, in particular executive func- tions, which are necessary for the implementation of goal- directed behavior.51 As mentioned previously, associations have been found between the results of physical performance tests and executive function. The strengths of the present study are that it is a population-based cohort study, involving a large number of old to very old community-dwelling people without clinical dementia. Examinations were conducted both at the research center and at the subjects’ homes, in order to reduce the effect of selection bias of the frailest individuals. Established, separate standardized tests of physical performance were applied and assessed by trained, licensed nurses. Several possible confounders that could influence the test results were also taken into account, such as comorbidity, education, lifestyle factors, medication, and pain. Using measures that are educationally unbiased may be of value when assessing elderly people with varying or lower levels of education, or backgrounds that differ linguistically or culturally.62 Physical performance tests that assess postural control and movements of the lower extremities that are sensitive to cognitive decline may facilitate early diagnosis and the identification of elderly people in need of monitoring, with regard to both cognitive and physical function. A limitation of this study is that only subjects attending the research center performed the 2 × 15 m walking test, pos- sibly excluding more frail individuals and introducing a floor effect on parameters related to this test. One consequence of this may be that the actual differences in functioning may submit your manuscript | www.dovepress.com Dovepress 203