Maxime Geiger, Céline Bonnyaud, Bernard Bussel, Nicolas Roche
Physiology–Functional Testing Ward, AP-HP, Raymond Poincaré Teaching Hospital, 92380 Garches, France. E-mail: maxime.geiger@u-psud.fr
DOI: 10.2340/16501977-2315

Objective: To assess temporal congruence (the difference in performance-time and time to imagine) between the sub-tasks of the Expanded Timed Up and Go (ETUG) and imagined ETUG (iETUG) tests in patients with hemiparesis following unilateral hemispheric stroke, and to compare the results with those for with healthy subjects.
Design: Case-controlled study.
Subject/patients: Twenty patients with chronic stroke and 20 healthy subjects.
Methods: TUG, ETUG and iETUG test performance times were recorded for all participants. Temporal congruence was calculated with the following formula: (ETUG-iETUG)/[(ETUG+iETUG)/2]*100.
Results: Patients’ performances were slower than those of healthy subjects for all 5 sub-tasks of the TUG, ETUG and iETUG tests. However, there was no significant difference in temporal congruence between healthy subjects and patients. Intragroup analysis showed significant differences between the executed and the imagined conditions for both groups for the “walking”, “turn around” and “sitting” phases (healthy subjects p = 0. 01, p = 0. 03, p = 0. 03, and patients p = 0. 01, p = 0. 003, p = 0. 003, respectively).
Conclusion: Temporal congruence was similar for healthy subjects and patients for all sub-tasks of the ETUG test. Moreover, temporal congruence was reduced for the same sub-tasks of the ETUG test in patients and healthy subjects. This suggests that the motor imagery involved the same cerebral structures in both groups, probably including the cerebellum, since it was intact in all patients.

When we ask patients with stroke to imagine themselves in a functional activity including different movements such as standing up from a chair, walking three meters to attempt a target and get back to the chair and sitting down like in the clinical assessment called Timed Up and Go (TUG), patients with stroke exhibit more difficulties than healthy subjects. However, when each subtask of the TUG is sequenced, all subjects (patients with stroke and healthy subjects) have the same performances. Indeed: they show same difficulties to imagine certain sub-task whereas others are perfectly done. These differences likely suggest that this is not the same central nervous system structures that are involved in the imagination of the different subtasks which compose the TUG. In regards of the literature and the results of patients included in this study, it is possible that the cerebellum plays a key role in the imagination of some subtasks of the TUG since the comparison of the results between stroke patients and healthy subjects were similar and because this structure was always intact in the two-population studied. This seems to indicate that the difference of motor imagery performance depends on the nature of the task performed by the patients during clinical care.