Effect of body orientation on proprioception during active and passive motions.

OBJECTIVE: To investigate whether passive and active reproduction of joint position, as well as detection of passive motion (as measures of a subject's proprioception) of the shoulder differ while sitting compared with lying supine. DESIGN: Shoulder proprioception of 28 healthy subjects (age, 22.2 +/- 1.7 yrs, 15 men) was tested. To test proprioception, angular motion (in degrees) for threshold to detection of passive motion and absolute matching error (in degrees) for passive and active reproduction of joint position were measured using an isokinetic dynamometer. As a measure of consistency, the standard deviation per subject and test (threshold to detection of passive motion and passive and active reproduction of joint position) was measured over three trials. The test scores during sitting and lying supine were compared using repeated-measures analysis of variance. RESULTS: No effect of body orientation on threshold to detection of passive motion and passive and active reproduction of joint position scores was found. Significantly larger errors were found during active reproduction of joint position compared with passive reproduction of joint position (F = 58.5; P < 0.01), and subjects were also significantly less accurate during active reproduction of joint position (F = 30.1; P < 0.01). CONCLUSIONS: Body orientation does not significantly influence proprioceptive errors or consistency, whereas movement mode (active or passive) does. The significance of these findings is that, depending on the situation or the patient's ability, proprioception tests can be conducted while they are lying or sitting, but movement modes cannot be used interchangeably.

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.