Bilateral Coupling Facilitates Recovery of Rhythmical Movements From Perturbation in Healthy and Post-Stroke Subjects.

Bilateral coupling facilitates recovery of rhythmical movements from perturbation in healthy and post-stroke subjects.

Exp Brain Res. 2013 Apr 23;
Ustinova KI, Feldman AG, Levin MF

The paretic arm of subjects with stroke has a decreased ability to quickly adapt to and recover from perturbations during rhythmical arm swinging. We investigated whether bilateral coupling in the synchronous motion of two arms may facilitate the restoration of rhythmical movement of the paretic arm in subjects with chronic hemiparesis due to stroke. While standing, stroke and age-matched healthy (control) subjects swung one or both arms synchronously at ~0.8 Hz from the shoulder joints. In randomly selected cycles, one arm was transiently arrested by an electromagnetic device when moving forward or backward. In the control group, bilateral swinging resumed faster than unilateral swinging regardless of which arm was perturbed. In the stroke group, this effect was observed only when the perturbation was applied to the paretic arm, suggesting that the motion of the non-paretic arm accelerated the recovery from perturbation of the paretic arm. In addition, bilateral swinging resumed after reduced anterior-posterior excursions of both arms in stroke subjects. Results confirm previous findings that bilateral swinging is normally guided by central changes in the referent configuration of the two arms that function as a single unit. As a consequence, both arms cooperate in recovery from perturbation of motion applied to one arm. Results also suggest that stroke-related brain damage alters the symmetry of bilateral interaction, resulting in deficits of inter-manual cooperative action. The involvement of the non-paretic arm could be beneficial for the recovery of swinging of both arms and may also facilitate movements of the paretic arm in certain tasks. HubMed – rehab


Posterior Condylar Offset Does Not Correlate With Knee Flexion After TKA.

Clin Orthop Relat Res. 2013 Apr 23;
Ishii Y, Noguchi H, Takeda M, Sato J, Toyabe SI

BACKGROUND: Studies of medial and lateral femoral posterior condylar offset have disagreed on whether posterior condylar offset affects maximum knee flexion angle after TKA. QUESTIONS/PURPOSES: We asked whether posterior condylar offset was correlated with knee flexion angle 1 year after surgery in (1) a PCL-retaining meniscal-bearing TKA implant, or in (2) a PCL-substituting mobile-bearing TKA implant. METHODS: Knee flexion angle was examined preoperatively and 12 months postoperatively in 170 patients who underwent primary TKAs to clarify the effect of PCL-retaining (85 knees) and PCL-substituting (85 knees) prostheses on knee flexion angle. A quasirandomized design was used; patients were assigned to receive one or the other implant using chart numbers. A quantitative three-dimensional technique with CT was used to examine individual changes in medial and lateral posterior condylar offsets. RESULTS: In PCL-retaining meniscal-bearing knees, there were no significant correlations between posterior condylar offset and knee flexion at 1 year. In these knees, the mean (± SD) postoperative differences in medial and lateral posterior condylar offsets were 0.0 ± 3.6 mm and 3.8 ± 3.6 mm, respectively. The postoperative change in maximum knee flexion angle was -5° ± 15°. In PCL-substituting rotating-platform knees, similarly, there were no significant correlations between posterior condylar offset and knee flexion 1 year after surgery. In these knees, the mean postoperative differences in medial and lateral posterior condylar offsets were -0.5 ± 3.3 mm and 3.3 ± 4.2 mm, respectively. The postoperative change in maximum knee flexion angle was -2° ± 18°. CONCLUSIONS: Differences in individual posterior condylar offset with current PCL-retaining or PCL-substituting prostheses did not correlate with changes in knee flexion 1 year after TKA. We should recognize that correctly identifying which condyle affects the results of the TKA may be difficult with conventional radiographic techniques. LEVEL OF EVIDENCE: Level II, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence. HubMed – rehab


Effect of Anodal Versus Cathodal Transcranial Direct Current Stimulation on Stroke Rehabilitation: A Pilot Randomized Controlled Trial.

Neurorehabil Neural Repair. 2013 Apr 22;
Khedr EM, Shawky OA, El-Hammady DH, Rothwell JC, Darwish ES, Mostafa OM, Tohamy AM

OBJECTIVE: . We compared the long-term effect of anodal versus cathodal transcranial direct current stimulation (tDCS) on motor recovery in patients after subacute stroke. METHODS: . Forty patients with ischemic stroke undergoing rehabilitation were randomly assigned to 1 of 3 groups: Anodal, Cathodal (over-affected and unaffected hemisphere, respectively), and Sham. Each group received tDCS at an intensity of 2 mA for 25 minutes daily for 6 consecutive days over of the motor cortex hand area. Patients were assessed with the National Institutes of Health Stroke Scale (NIHSS), Orgogozo’s MCA scale (OMCASS), the Barthel index (BI), and the Medical Research Council (MRC) muscle strength scale at baseline, after the sixth tDCS session and then 1, 2, and 3 months later. Motor cortical excitability was measured with transcranial magnetic stimulation (TMS) at baseline and after the sixth session. RESULTS: . By the 3-month follow-up, all groups had improved on all scales with P values ranging from .01 to .0001. Improvement was equal in the Anodal and Cathodal groups. When these treated groups were combined and compared with Sham, significant interactions were seen for the OMCASS and BI scales of functional ability (P = .002 for each). There was increased cortical excitability of the affected hemisphere in all groups with the changes being greater in the real versus sham groups. There were borderline significant improvements in muscle strength. CONCLUSION: . A brief course of 2 types of tDCS stimulation is superior to sham stimulation in enhancing the effect of rehabilitation training to improve motor recovery after stroke. HubMed – rehab