Relationship among shoulder proprioception, kinematics, and pain after stroke.

OBJECTIVE: To identify a possible relationship among chronic poststroke shoulder pain (PSSP), scapular resting pose, and shoulder proprioception. DESIGN: Case-control study. SETTING: Rehabilitation center. PARTICIPANTS: A total of 21 inpatients with stroke and 10 healthy control subjects. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Orientations of both the contralateral and ipsilateral (ie, paretic and nonparetic) shoulders during rest in degrees, angular displacement (degrees) for threshold to detection of passive motion (TDPM) tests, and absolute error (degrees) for passive reproduction of joint position (PRJP) tests. RESULTS: The contralateral shoulder of patients with PSSP showed more scapular lateral rotation and larger TDPM and PRJP scores than both patients without PSSP and control subjects. Additionally, the contralateral shoulder of patients with deteriorated proprioception showed more scapular lateral rotation than control subjects, whereas their ipsilateral shoulder showed more scapular lateral rotation than both control subjects and patients with good proprioception. CONCLUSIONS: A clear relation among affected shoulder kinematics, affected proprioception, and PSSP was found. In determining the risk of developing PSSP, attention should be paid to a patients shoulder proprioception and kinematics. If both are altered after stroke, this could worsen the initial pathology or cause secondary pathologies and thus initiate a vicious circle of repetitive soft tissue damage leading to chronic PSSP. Additionally, more attention should be paid to the ipsilateral (ie, nonparetic) shoulder because it could be used in determining the risk of developing PSSP in the contralateral (ie, paretic) shoulder.

Proprioception of the shoulder after stroke.

OBJECTIVE: To investigate position sense and kinesthesia of the shoulders of stroke patients. DESIGN: Case-control study. SETTING: A rehabilitation center. PARTICIPANTS: A total of 22 inpatients with stroke and 10 healthy control subjects. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Angular displacement (in degrees) for threshold to detection of passive motion (TDPM) tests and absolute error (in degrees) for passive reproduction of joint position tests. RESULTS: For patients, the TDPM for internal and external rotation was significantly higher for both the contralateral (paretic) side (internal, 7.92 degrees +/-7.19 degrees ; external, 8.46 degrees +/-8.87 degrees ) and the ipsilateral (nonparetic) side (internal, 4.86 degrees +/-5.03 degrees ; external, 6.09 degrees +/-9.15 degrees ) compared with the control group (internal, 1.83 degrees +/-1.09 degrees ; external, 1.71 degrees +/-.85 degrees ). Also, for internal rotation, TDPM was significantly higher for patients on the contralateral side compared with the ipsilateral side. For passive reproduction of joint position tests, no differences were found. CONCLUSIONS: Both the contralateral and ipsilateral shoulders of stroke patients showed impaired TDPM. Passive reproduction of joint position does not seem to be affected as a result of a stroke. The control of the muscle spindles and central integration or processing problems of the afferent signals provided by muscle spindles might cause these effects.

Kinematic alterations in the ipsilateral shoulder of patients with hemiplegia due to stroke.

OBJECTIVE: To evaluate the assumption that shoulder kinematic patterns of the ipsilateral, nonparetic shoulder in hemiplegia are similar to kinematics recorded in a healthy population. DESIGN: Case control study of a convenience sample of ten patients with hemiplegia due to stroke in the subacute phase compared with a control group of similar age. Three-dimensional positions of the scapula and humerus were measured and expressed in Euler angles as a function of active arm elevation in the frontal and sagittal plane and during passive humeral internal/external rotation at an elevation angle of 90 degrees in the frontal and sagittal plane. RESULTS: Compared with controls, in the ipsilateral shoulder of patients, we found both a statistically significant diminished scapular protraction during elevation in the sagittal plane (35 +/- 5 vs. 51 +/- 8 degrees at 110 degrees of humeral elevation) and humeral external rotation during arm elevation in the frontal plane (51 +/- 7 vs. 69 +/- 14 degrees at 110 degrees of humeral elevation). Maximal passive humeral external rotation was found to be impaired in the frontal (64 +/- 13 vs. 98 +/- 14 degrees) and sagittal planes (65 +/- 11 vs. 94 +/- 12 degrees). In addition, there was significantly diminished anterior spinal tilt during humeral internal rotation (-5 +/- 10 vs. -20 +/- 9 degrees) and diminished posterior spinal tilt during external rotation in the frontal plane (-14 +/- 8 vs. -3 +/- 6 degrees). Maximal thoracohumeral elevation in patients was significantly impaired (126 +/- 12 vs. 138 +/- 8 degrees). CONCLUSION: Clear kinematic changes in the ipsilateral shoulder in patients with hemiplegia were found, indicating underlying alterations in muscle contraction patterns. The cause remains speculative. These results suggest that the ipsilateral shoulder should not be considered to function normally beforehand.