Bilateral changes in 3-D scapular kinematics in individuals with chronic stroke.

BACKGROUND: Stroke can lead to altered scapular motion that may limit the ability to perform activities of daily living. The aims were to evaluate scapular kinematics of individuals with chronic stroke and the correlation with paretic arm function. METHODS: Scapular kinematics was assessed in thirty-four individuals (Chronic stroke=17; controls=17) during arm elevation and lowering in scapular and self-selected planes, and during hair combing. The use of the paretic arm to perform activities of daily living was assessed by the Motor Activity Log (MAL-30). Scapular kinematics was compared among paretic and non-paretic arms, and controls. Correlation between scapular kinematics and MAL-30 was also verified. FINDINGS: Paretic and non-paretic arms showed increased scapular internal rotation (p<0.05) during arm lowering in the scapular plane, and during arm elevation and lowering in the self-selected plane compared to controls. Increased internal rotation (p<0.05) was also found in the paretic arm during hair combing compared to controls. Increased scapular anterior tilt (p<0.05) was observed in the paretic arm during arm elevation while performing the activity of hair combing and during arm elevation and lowering in the scapular and self-selected planes compared to controls. The non-paretic arm showed increased anterior tilt (p<0.05) during arm elevation and lowering in self-selected plane compared to controls. No difference in scapular upward rotation among neither arms, nor correlation between scapular kinematics and MAL-30 were found (p>0.05). INTERPRETATION: Individuals with chronic stroke showed bilateral scapular kinematics alterations. However, these alterations are not correlated with paretic arm function.

Muscle atrophy, voluntary activation disturbances, and low serum concentrations of IGF-1 and IGFBP-3 are associated with weakness in people with chronic stroke.

BACKGROUND: The muscle weakness that is exhibited poststroke is due to a multifactorial etiology involving the central nervous system and skeletal muscle changes. Insulinlike growth factor 1 (IGF-1) and IGF binding protein 3 (IGFBP-3) have been described as biomarkers of neuromuscular performance in many conditions. However, no information about these biomarkers is available for people with chronic hemiparesis. OBJECTIVE: The purpose of this study was to investigate possible factors involved in muscle weakness, such as IGF-1 and IGFBP-3 serum concentrations, muscle volume, and neuromuscular performance of the knee flexors and extensors, in people with chronic hemiparesis poststroke. DESIGN: This was a cross-sectional study. METHODS: A cross-sectional study was performed on 14 individuals poststroke who were paired with healthy controls. Mobility, function, balance, and quality of life were recorded as outcome measures. Knee flexor and extensor muscle volumes and neuromuscular performance were measured using nuclear magnetic resonance imaging, dynamometry, and electromyography. The serum concentrations of IGF-1 and IGFBP-3 were quantified by enzyme-linked immunosorbent assay (ELISA). RESULTS: The hemiparetic group had low serum concentrations of IGF-1 (25%) and IGFBP-3 (40%); reduced muscle volume in the vastus medialis (32%), vastus intermedius (29%), biceps femoris (16%), and semitendinosus and semimembranosus (12%) muscles; reduced peak torque, power, and work of the knee flexors and extensors; and altered agonist and antagonist muscle activation compared with controls. CONCLUSIONS: Low serum concentrations of IGF-1 and IGFBP-3, deficits in neuromuscular performance, selective muscle atrophy, and decreased agonist muscle activation were found in the group with chronic hemiparesis poststroke. Both hemorrhagic and ischemic stroke were considered, and the data reflect a chronic poststroke population with good function.