Selection of the Better Dual-Timed Up and Go Cognitive Task to Be Used in Patients With Stroke Characterized by Subtraction Operation Difficulties

Background: The Timed Up and Go Test (TUG) with serial subtraction is commonly used to assess cognitive-dual task performance during walking for fall prediction. Some stroke patients cannot perform number subtraction and it is unclear which cognitive task can be used to substitute for the subtraction task in the TUG test. The aim of this study was to determine the type of cognitive task that produced the highest decrease on both motor and cognitive performances during TUG-dual in stroke patients. Methods: A total of 23 persons with stroke but capable of completing subtraction (ST) and 19 persons with subtraction operation difficulties (SOD) participated. Both groups have a similar age range (ST: 59.3 ± 10.4 years and SOD: 62.0 ± 6.8 years) and stroke onset duration (ST: 44.13 ± 62.29 months and SOD: 42.34 ± 39.69 months). The participants performed TUG without a cognitive task (TUG-single) followed by a cognitive task when seated (cognitive-single). In addition, TUG with a cognitive task (TUG-dual) was performed, with the activity randomly selected from four cognitive tasks, including alternate reciting, auditory working memory, clock task, and phonologic fluency. The main outcome variables—TUG duration measured by OPAL accelerometer and cognitive-dual task effect (DTE)—were analyzed using repeated-measures analyses of variance (ANOVA). Results: The number of correct responses when seated were significantly lower in the SOD as compared to the ST (p < 0.05) during all cognitive tasks, except the phonologic fluency. During TUG-cognitive, TUG duration in the ST was significantly longer for all cognitive tasks compared with TUG-single (p < 0.0001), whereas TUG duration in the SOD was significantly increased only during the phonologic fluency task (p < 0.01). In the ST, there was a significant difference in cognitive DTE between the subtraction and the phonologic fluency tasks (p < 0.01). The highest cognitive cost was found in the subtraction task, whereas the highest cognitive benefit was shown in the phonologic fluency task. No significant cognitive DTE was found among the cognitive tasks in the SOD. Conclusion: For stroke persons with SOD, phonologic fluency is suitable to be used in the TUG-cognitive assessment. In contrast, subtraction (by 3s) is recommended for the assessment of TUG-cognitive in stroke persons who can perform subtraction.