A single session of anodal transcranial direct current stimulation applied over the affected primary motor cortex does not alter gait parameters in chronic stroke survivors.

OBJECTIVES: The excitability of some neural circuits involved in walking and affected in individuals with chronic stroke can be modulated during and/or immediately after anodal transcranial direct current stimulation (a-tDCS). This study was designed to investigate the effects of a-tDCS during and immediately after application on leg muscle activity during gait, and on spatiotemporal and kinematic gait parameters in patients with chronic stroke. METHODS: This study was randomized, sham-controlled and double-blinded with a cross-over design and included 24 individuals with chronic stroke. Each participant underwent one 30-minute session each of effective a-tDCS at 2mA and sham tDCS. In both sessions, the anode was placed over the leg motor cortex of the affected hemisphere and the cathode over the contralateral orbit. Six gait trials were performed before, during and immediately after each effective/sham tDCS session. Electromyographic activity of leg muscles, as well as spatiotemporal (e.g. gait speed) and kinematic (e.g. peak knee flexion and ankle dorsiflexion in the swing phase of gait) gait parameters were recorded. Genotyping for the brain-derived neurotrophic factor (BDNF) Val66Met polymorphism was undertaken since this gene may influence motor skill learning and the effects of tDCS. RESULTS: No significant effects of a-tDCS on gait parameters were found either for the total group or for the Val66Met (N=10) and Val66Val (N=14) subgroups. CONCLUSION: A single session of a-tDCS delivered to the leg motor cortex did not immediately improve gait parameters in individuals with chronic stroke, regardless of their BDNF genotype.

Effect of botulinum toxin injection on length and force of the rectus femoris and triceps surae muscles during locomotion in patients with chronic hemiparesis (FOLOTOX).

BACKGROUND: After stroke, spasticity of the rectus femoris (RF) and triceps surae (TS) muscles frequently alters the gait pattern. Knee flexion and ankle dorsiflexion in swing are often reduced, respectively called Stiff Knee Gait (SKG) and equinus. A preliminary uncontrolled study suggested that botulinum toxin type A (BTX-A) injections could improve muscle length and force generated during gait, improving inter-segmental coordination. The aim of this randomised controlled study is thus to evaluate changes in the length of the RF and TS muscles during gait 1 month after either BTX-A or placebo injection in patients with chronic stroke, SKG and spastic equinus. The secondary aims are to evaluate peak length and peak force generated during gait, as well inter-segmental coordination assessed using the continuous relative phase method initially described by Barela et al. in patients with stroke. METHODS: This is a prospective, three-centre, randomised, placebo-controlled, triple blind study over 3 months with 4 visits. Forty patients will be included. During visits V1, V3 and V4, length and force generated by RF and TS during gait will be assessed using musculoskeletal models (MSM). Muscle force will also be assessed using an isokinetic dynamometer. Inter segmental coordination will be evaluated using 3D gait analysis and functional tests will be performed. During V2, patients will receive either an injection of BTX-A in the RF and TS muscles or a placebo injection of saline solution. DISCUSSION: We expect an increase in peak length and a decrease in peak force generated by the RF and TS muscles in the BTX-A group 1 month post injection. Moreover, we expect these parameters to be more improved in the BTX-A than the Control group. This is the first study to assess these parameters in a randomised, controlled trial using instrumented methods (isokinetic evaluation and 3D gait analysis). The results should help to improve understanding of the mechanism(s) underlying improvements in inter-segmental coordination that have been found in many previous uncontrolled studies. TRIAL REGISTRATION: ClinicalTrials.gov: NCT01821573 , First received: March 27, 2013 Last updated: September 14, 2016 Last verified: September 2016 Other Study ID Numbers: P110136 AOM11223.

Assessing of imagined and real expanded Timed Up and Go tests in patients with chronic stroke: A case-control study.

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.

Evaluating the Effect of Cognitive Dysfunction on Mental Imagery in Patients with Stroke Using Temporal Congruence and the Imagined 'Timed Up and Go' Test (iTUG).

BACKGROUND: Motor imagery (MI) capacity may be altered following stroke. MI is evaluated by measuring temporal congruence between the timed performance of an imagined and an executed task. Temporal congruence between imagined and physical gait-related activities has not been evaluated following stroke. Moreover, the effect of cognitive dysfunction on temporal congruence is not known. OBJECTIVE: To assess temporal congruence between the Timed Up and Go test (TUG) and the imagined TUG (iTUG) tests in patients with stroke and to investigate the role played by cognitive dysfunctions in changes in temporal congruence. METHODS: TUG and iTUG performance were recorded and compared in twenty patients with chronic stroke and 20 controls. Cognitive function was measured using the Montreal Cognitive Assessment (MOCA), the Frontal Assessment Battery at Bedside (FAB) and the Bells Test. RESULTS: The temporal congruence of the patients with stroke was significantly altered compared to the controls, indicating a loss of MI capacity (respectively 45.11 ±35.11 vs 24.36 ±17.91, p = 0.02). Furthermore, iTUG test results were positively correlated with pathological scores on the Bells Test (r = 0.085, p = 0.013), likely suggesting that impairment of attention was a contributing factor. CONCLUSION: These results highlight the importance of evaluating potential attention disorder in patients with stroke to optimise the use of MI for rehabilitation and recovery. However further study is needed to determine how MI should be used in the case of cognitive dysfunction.