Movement Component Analysis of Reaching Strategies in Individuals With Stroke: Preliminary Study

BACKGROUND

Upper limb motor paresis is a major symptom of stroke, which limits activities of daily living and compromises the quality of life. Kinematic analysis offers an in-depth and objective means to evaluate poststroke upper limb paresis, with anticipation for its effective application in clinical settings.

OBJECTIVE

This study aims to compare the movement strategies of patients with hemiparesis due to stroke and healthy individuals in forward reach and hand-to-mouth reach, using a simple methodology designed to quantify the contribution of various movement components to the reaching action.

METHODS

A 3D motion analysis was conducted, using a simplified marker set (placed at the mandible, the seventh cervical vertebra, acromion, lateral epicondyle of the humerus, metacarpophalangeal [MP] joint of the index finger, and greater trochanter of the femur). For the forward reach task, we measured the distance the index finger's MP joint traveled from its starting position to the forward target location on the anterior-posterior axis. For the hand-to-mouth reach task, the shortening of the vertical distance between the index finger MP joint and the position of the chin at the start of the measurement was measured. For both measurements, the contributions of relevant upper limb and trunk movements were calculated.

RESULTS

A total of 20 healthy individuals and 10 patients with stroke participated in this study. In the forward reach task, the contribution of shoulder or elbow flexion was significantly smaller in participants with stroke than in healthy participants (mean 52.5%, SD 24.5% vs mean 85.2%, SD 4.5%; P<.001), whereas the contribution of trunk flexion was significantly larger in stroke participants than in healthy participants (mean 34.0%, SD 28.5% vs mean 3.0%, SD 2.8%; P<.001). In the hand-to-mouth reach task, the contribution of shoulder or elbow flexion was significantly smaller in participants with stroke than in healthy participants (mean 71.8%, SD 23.7% vs mean 90.7%, SD 11.8%; P=.009), whereas shoulder girdle elevation and shoulder abduction were significantly larger in participants with stroke than in healthy participants (mean 10.5%, SD 5.7% vs mean 6.5%, SD 3.0%; P=.02 and mean 16.5%, SD 18.7% vs mean 3.0%, SD 10.4%; P=.02, respectively).

CONCLUSIONS

Compared with healthy participants, participants with stroke achieved a significantly greater distance via trunk flexion in the forward reach task and shoulder abduction and shoulder girdle elevation in the hand-to-mouth reach task, both of these differences are regarded as compensatory movements. Understanding the characteristics of individual motor strategies, such as dependence on compensatory movements, may contribute to tailored goal setting in stroke rehabilitation.

Treatment of upper limb spasticity with inhibitory repetitive transcranial magnetic stimulation: A randomized placebo-controlled trial

BACKGROUND

Upper limb dysfunction is a frequent complication after stroke impairing outcome. Inhibitory repetitive transcranial magnetic stimulation (rTMS) applied over the contralesional hemisphere is supposed to enhance the positive effects of conventional rehabilitative treatment.

OBJECTIVE

This double-blind randomized placebo-controlled trial investigated whether inhibitory rTMS as add-on to standard therapy improves upper limb spasticity.

METHODS

Twenty-eight patients (aged 44 to 80 years) with unilateral stroke in the middle cerebral artery territory were analyzed. Participants were randomly assigned to inhibitory, low-frequency (LF-) rTMS (n = 14) or sham-rTMS (n = 14). The primary outcome measure was the spasticity grade, which was assessed with the Modified Ashworth Scale (MAS). In addition, the Fugl-Meyer-Assessment (FMA) for the upper extremity (UE) and a resting-state fMRI were performed to measure motor functions and the sensorimotor network, respectively.

RESULTS

The MAS score was reduced in the LF-rTMS group only, whereas the FMA score improved in both groups over time. Regarding the fMRI data, both groups activated typical regions of the sensorimotor network. In the LF-rTMS group, however, connectivity to the left angular gyrus increased after treatment.

CONCLUSION

Changes in functional connectivity in patients receiving inhibitory rTMS over the contralesional motor cortex suggest that processes of neuronal plasticity are stimulated.

Multimodal Assessment of the Motor System in Patients With Chronic Ischemic Stroke

BACKGROUND AND PURPOSE

Despite continuing efforts in the multimodal assessment of the motor system after stroke, conclusive findings on the complementarity of functional and structural metrics of the ipsilesional corticospinal tract integrity and the role of the contralesional hemisphere are still lacking. This research aimed to find the best combination of motor system metrics, allowing the classification of patients into 3 predefined groups of upper limb motor recovery.

METHODS

We enrolled 35 chronic ischemic stroke patients (mean 47 [26-66] years old, 29 [6-58] months poststroke) with a single supratentorial lesion and unilateral upper extremity weakness. Patients were divided into 3 groups, depending on upper limb motor recovery: good, moderate, and bad. Nonparametric statistical tests and regression analysis were used to investigate the relationships among microstructural (fractional anisotropy (FA) ratio of the corticospinal tracts at the internal capsule (IC) level (classic method) and along the length of the tracts (Fréchet distance), and of the corpus callosum) and functional (motor evoked potentials [MEPs] for 2 hand muscles) motor system metrics. Stratification rules were also tested using a decision tree classifier.

RESULTS

IC FA ratio in the IC and MEP absence were both equally discriminative of the bad motor outcome (96% accuracy). For the 3 recovery groups' classification, the best parameter combination was IC FA ratio and the Fréchet distance between the contralesional and ipsilesional corticospinal tract FA profiles (91% accuracy). No other metrics had any additional value for patients' classification. MEP presence differed for 2 investigated muscles.

CONCLUSIONS

This study demonstrates that better separation between 3 motor recovery groups may be achieved when considering the similarity between corticospinal tract FA profiles along its length in addition to region of interest-based assessment and lesion load calculation. Additionally, IC FA ratio and MEP absence are equally important markers for poor recovery, while for MEP probing it may be important to investigate more than one hand muscle.