Stella Maris Michaelsen

Task-Specific Training With Trunk Restraint on Arm Recovery in Stroke Randomized Control Trial

Background and Purpose— Task-specific training improves functional outcomes after stroke. However, gains may be accompanied by increases in movements compensating for motor impairments. We hypothesized that restriction of compensatory trunk movements may encourage recovery of premorbid movement patterns leading to better functional outcomes. The goal was to determine whether task-specific training with trunk-restraint (TR) produces greater improvements in arm impairment and function than training without TR in patients with chronic hemiparesis. Methods— Double-blind randomized control trial of a therapist-supervised home program (3 times per week, 5 weeks) in 30 patients with chronic hemiparesis stratified by arm impairment level (Fugl-Meyer) was performed. Intervention group (TR group) received progressive object-related reach-to-grasp training with prevention of trunk movements. Control group (C) practiced tasks without TR. Main outcome measures were upper limb impairment (Fugl-Meyer Arm Section) and function (TEMPA) and movement kinematics (trunk displacement, elbow extension; Optotrak, 10 trials) of a reach-to-grasp movement. Evaluations were repeated before, immediately after, and 1 month postintervention by blind evaluators. Results— TR training led to greater improvements in impairment and function compared with C. Improvements were accompanied by increased active joint range and were greater in initially more severe patients. In these patients, TR decreased trunk movement and increased elbow extension, whereas C had opposite effects (increased compensatory movements). In TR, changes in arm function were correlated with changes in arm and trunk kinematics. Conclusions— Treatment should be tailored to arm impairment severity with particular attention to controlling excessive trunk movements if the goal is to improve arm movement quality and function.

Use of the trunk for reaching targets placed within and beyond the reach in adult hemiparesis

Multijoint movements such as reaching are impaired after brain lesions involving sensorimotor areas and pathways. However, the mechanisms by which such lesions affect motor control are not fully understood. Direct effects of the lesion may be partly compensated by both the system’s redundancy and its plasticity. Indeed stroke patients with limited arm movement can reach objects placed within the reach of the arm by using a compensatory strategy involving trunk recruitment. A similar strategy is observed in healthy individuals reaching for objects placed beyond the reach of the arm. Determining the control mechanism(s) governing this compensatory strategy in stroke patients was the goal of this study. Kinematics of reaching movements in hemiparetic and healthy participants to targets placed within and beyond the length of the arm were analysed. Targets were placed sagittally in front of the midline of the body. Two targets (targets 1 and 2) were within reaching distance defined as the length of the stretched arm from axilla to wrist crease. Two others were beyond arm’s reach so that one required a forward trunk inclination (target 3) and the other required body raising to a semi-standing position (target 4). Healthy participants used minimal trunk displacement for reaches to targets 1 and 2. For reaches to targets 3 and 4, trunk displacement increased with target distance. Whenever the trunk was involved, there was a stereotyped sequential recruitment of the arm and trunk in that the trunk began moving simultaneously with or before the hand and stopped moving after the end of hand movement. This suggested that the control system predicts that the trunk movement will be needed to extend the reach and includes the trunk, in an anticipatory way, into the reach. In contrast, most hemiparetic participants recruited their trunk for reaches to all four targets, even those placed close to the body. Similar to healthy individuals, the sequence of hand and trunk recruitment was stereotyped, suggesting that temporal planning aspects of the motor program underlying movement coordination were relatively unaffected. In contrast to healthy participants, the contribution of the trunk movement to the endpoint displacement was substantially higher in the hemiparetic group and occurred earlier in the reach. It is suggested that the target distance at which the trunk is integrated into the movement to extend the reach of the arm is attained around the limit of arm extension and that this limit is reduced in hemiparetic individuals.

Effect of Trunk Restraint on the Recovery of Reaching Movements in Hemiparetic Patients

Background and Purpose— Reaching movements made with the affected arm in hemiparetic patients are often accompanied by compensatory trunk or shoulder girdle movements, which extend the reach of the arm. We investigated the effects of the suppression of these compensatory movements on reaching ability in hemiparetic individuals. Methods— Eleven healthy and 11 hemiparetic individuals participated. Three-dimensional kinematic analysis was used to quantify reaches made to a close and a distant target (near the limit of arm’s length). Unrestrained reaches were compared with those in which shoulder girdle and trunk movements were restrained by a harness. Results— During unrestrained reaching, abnormal trunk recruitment and limitations in elbow and shoulder movements were correlated with the degree of clinical stroke severity (r =−0.91 to −0.96) in hemiparetic patients. During trunk restraint, ranges of elbow and shoulder joint movement increased in both groups. In addition, elbow and shoulder interjoint coordination improved. This was caused by increases in the range of joint motion as well as by a better dynamic temporal relation between joints. Conclusions— Trunk restraint allowed patients with hemiparetic stroke to make use of arm joint ranges that are present but not normally recruited during unrestrained arm-reaching tasks. Thus, the underlying “normal” patterns of movement coordination may not be entirely lost after stroke. Appropriate treatments, such as trunk restraint, may be effective in uncovering latent movement patterns to maximize arm recovery in hemiparetic patients.

Compensation for distal impairments of grasping in adults with hemiparesis.

Previous studies have shown that patients with arm and hand paresis following stroke recruit an additional degree of freedom (the trunk) to transport the hand during reaching and use alternative strategies for grasping. The few studies of grasping parameters of the impaired hand have been case studies mainly focusing on describing grasping in the presence of particular impairments such as hemi-neglect or optic ataxia and have not focussed on the role of the trunk in prehension. We hypothesized that the trunk movement not only ensures the transport of the hand to the object, but it also assists in orienting the hand for grasping when distal deficits are present. Nineteen patients with chronic hemiparesis and seven healthy subjects participated in the study. Patients had sustained a stroke of non-traumatic origin 6–82xa0months previously (31±22xa0months) and had mild or moderate to severe arm paresis. Using a whole hand grasp, subjects reached and grasped a cylinder (35xa0mm) that was placed sagittally (T1) or at a 45° angle to the sagittal midline in the ipsilateral workspace (T2), both at about 90% arm’s length (10 trials per target). Eight infrared emitting diodes were placed on bony landmarks of the hand, arm and trunk and kinematic data were recorded by an optical motion analysis system (Optotrak) for 2–5xa0s at 120xa0Hz. Hand position and orientation were recorded by a Fastrack Polhemus system. Our results show that during goal-directed prehension tasks, individuals with hemiparesis oriented the hand more frontally for grasping and used more trunk anterior displacement or rotation to transport the hand to the target compared to healthy subjects. Despite these changes, the major characteristics of reaching and grasping such as grip aperture size, temporal coordination between hand transport and aperture formation and the relative timing of grip aperture were largely preserved. For patients with more severe distal impairments, the amount of trunk displacement was also correlated with a more frontal hand orientation for grasping. Furthermore, in healthy subjects and patients without distal impairments, the trunk movement was mostly related to proximal arm movements while in those with distal impairments, trunk movement was related to both proximal and distal arm movements. Data support the hypothesis that the trunk movement is used to assist both arm transport and hand orientation for grasping when distal deficits are present.

Short-Term Effects of Practice With Trunk Restraint on Reaching Movements in Patients With Chronic Stroke A Controlled Trial

Background and Purpose— In prehension tasks with objects placed within arm’s reach, patients with hemiparesis caused by stroke use excessive trunk movement to compensate for arm motor impairments. Compensatory trunk movements may improve motor function in the short term but may limit arm recovery in the long term. Previous studies showed that restriction of trunk movements during reach-to-grasp movements results in immediate increases in active arm joint ranges and improvement in interjoint coordination. To evaluate the potential of this technique as a therapeutic intervention, we compared the effects of short-term reach-to-grasp training (60-trial training session) with and without physical trunk restraint on arm movement patterns in patients with chronic hemiparesis. Methods— A total of 28 patients with hemiparesis were assigned to 2 groups: 1 group practiced reach-to-grasp movements during which compensatory movement of the trunk was prevented by a harness (trunk restraint), and the second group practiced the same task while verbally instructed not to move the trunk (control). Kinematics of reaching and grasping an object placed within arm’s length were recorded before, immediately after, and 24 hours after training. Results— The trunk restraint group used more elbow extension, less anterior trunk displacement, and had better interjoint coordination than the control group after training, and range of motion was maintained 24 hours later in only the trunk restraint group. Conclusions— Restriction of compensatory trunk movements during practice may lead to greater improvements in reach-to-grasp movements in patients with chronic stroke than practice alone, and longer-term effects of this intervention should be evaluated.

Development and validation of two new sensory tests of the hand for patients with stroke

Objective: To establish validity and reliability of two new sensory tests evaluating moving (MTP) and sustained (STP) touch-pressure and their relationship to hand function for patients with stroke. The STP had four components in which a light or heavy ball was applied passively or held actively. Participants: Twenty-eight participants with hemiparesis (1–109 months) from rehabilitation hospitals or outpatient programmes. Design: Content validity was established. Then reliability and concurrent and construct validity were determined. Sensation was compared with hand functional ability using the Modified Moberg recognition task, the Box and Block test and one task of the TEMPA test. Results: Reliability: Both types of reliability were significant for MTP (ICC = 0.92) and all components of STP (ICC = 0.62 to 0.92). Concurrent validity:MTP and STP correlated significantly (r = -0.39 to -0.83) with the Semmes–Weinstein Monofilament test used as a ‘gold standard comparison. Construct validity: MTP was significantly related to Moberg (r = 0.49). Three of four components of STP correlated with TEMPA (r = 0.49–0.53) and Moberg (0.45–0.71). Only STP (heavy ball) correlated with Box and Block (0.42–0.48). Of the four components of STP, only the passive STP (light ball) was not related to hand function. Conclusion: The new sensory tests of moving, and three components of sustained touch-pressure were reliable. The passive STP (light ball) was discarded. All but this test were relevant to the two functional roles of sensation: exploration for MTP and dexterity during holding for STP.

Comparison of reaching and grasping kinematics in patients with hemiparesis and in healthy controls in virtual and physical environments

Kinematics of reaching and grasping movements to physical and virtual objects placed on a table in front of the body midline were compared in 10 healthy and 12 hemiparetic subjects post-stroke. Despite minor differences in performance variables (movement time, arm trajectory) and joint ranges, arm and hand movement patterns were similar in the two environments. Differences may be due to attributes of the VR environment. Relevance to rehabilitation will be discussed.