[Purpose] This study aimed to evaluate performance on the Timed Up and Go test (TUG) under dual-task (DT) conditions using arithmetic tasks, and to investigate the relationship between the TUG performances and cognitive functions or falls. [Subjects] Thirty frail elders, who were certified as being in need of care, with a mean age of 84.7 years (SD=4.1), participated in this study. [Methods] TUG was repeated under three DT conditions, counting backward by 1 s (DT-TUG-1), 3 s (DT-TUG-3), and 7 s (DT-TUG-7) and with no DT (ST-TUG). Gait speed was measured and gait abnormality was scoredfrom videotapes of the subjects performing ST-TUG and DT-TUG-3. Dual-task-cost (DTC) was calculated for each DT-TUG as follows: [(difference between DT and ST performance)/ ST performance] ×100. Cognitive functions were assessed using the Letter Fluency Test (LFT), the Color Trails Test (CTT), the Rey Auditory Verbal Learning Test (RAVLT), and the Mini-Mental State Examination (MMSE). The participantʼs history of falls in the past 6 months was recorded. [Results] Gait speed in DT-TUGs was significantly reduced as the number of the arithmetic tasks increased. Significant correlations were found between DTC-1 and each of CTT, RAVLT, and MMSE. In addition, correlations were foundbetween DTC-3 and CTT, and between DTC-7 and each of CTT, and MMSE. There was no significant difference in DTC between the two groups according to the participantʼs history of falls. [Conclusion] Gait speed was reduced with increasing DT complexity. Attention was the most influential cognitive factor on change of TUG under DT conditions.
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