Shirley A. Sahrmann

Sensorimotor Impairments and Reaching Performance in Subjects With Poststroke Hemiparesis During the First Few Months of Recovery

Background and Purpose Little is known about the relationship between upper-extremity (UE) sensorimotor impairment and reaching performance during the first few months after stroke. The purpose of this study was to examine: (1) how measures of UE sensorimotor impairment are related to the speed, accuracy, and efficiency of reaching in subjects with hemiparesis during the subacute phase after stroke and (2) how impairments measured during the acute phase after stroke may predict the variance in reaching performance a few months later. Subjects and Methods Upper-extremity sensorimotor impairments and reaching performance were evaluated in 39 subjects with hemiparesis at 2 time points: during the acute phase (8.7±3.6 [X̄±SD] days) and the subacute phase (108.7±16.5 days) after stroke. Ten subjects who were healthy (control subjects) were evaluated once. Regression analyses were used to determine which impairments were the best predictors of variance in reaching performance in the subacute phase after stroke. Results Only a small amount of variance (<30%) in reaching performance was explained at the subacute time point, using either acute or subacute impairments as predictor variables. Of the impairments measured, UE strength deficits were the strongest, most consistent predictors of the variance in reaching performance during the first 3 months after stroke. Discussion and Conclusion Surprisingly, the detailed clinical assessment of UE sensorimotor impairment, measured at the acute or subacute phase after stroke, did not explain much of the variance in reaching performance during the subacute phase after stroke. The findings that UE strength deficits (ie, decreased active range of motion and isometric force production) were the most common predictors of the variance in reaching performance during the first 3 months after stroke are consistent with the current viewpoint that impaired volitional muscle activation, clinically apparent as UE weakness, is a prominent contributing factor to UE dysfunction after stroke.

Relationships between upper-limb functional limitation and self-reported disability 3 months after stroke

This study explored relationships between upper-limb (UL) functional limitations and self-reported disability in stroke patients with relatively pure motor hemiparesis who were enrolled in an acute rehabilitation treatment trial. All participants were enrolled in the VECTORS (Very Early Constraint Treatment for Recovery from Stroke) study. VECTORS is a single-center pilot clinical trial of early application of constraint-induced movement therapy (CIMT). All 39 subjects who completed 90 days of VECTORS were included in this analysis. Trained study personnel who were blinded to the treatment type performed all evaluations. Data in this article examine relationships between assessments performed 90 days after stroke. Functional limitation measures included the Action Research Arm (ARA) test and Wolf Motor Function Test (WMFT), and self-reported disability measures included the Functional Independence Measure (FIM) and Motor Activity Log (MAL) (by telephone). Mean plus or minus standard deviation time from stroke onset to randomization was 9.4 plus or minus 4.3 days, and median time to follow-up was 99 days (range 68-178). Subjects with perfect or near-perfect scores on the ARA test or WMFT reported residual disability on the FIM and MAL. Quality of movement on the WMFT (functional ability score) was not strongly associated with self-reported frequency, and speed of movement on the WMFT (timed score) was not associated with self-reported frequency (MAL amount of use). In this early UL intervention trial, we found that perceived disability measures captured information that was not assessed by functional limitation and impairment scales. Our results indicate that excellent motor recovery as measured by functional limitation and impairment scales did not equal restoration of everyday productive UL use and speed of task completion did not translate to actual use. Our results confirm the need for a measurement strategy that is sensitive to change, assesses a broad performance range, and detects meaningful clinical improvements in early rehabilitation intervention trials.

Recovery of Grasp versus Reach in People with Hemiparesis Poststroke

Background and Objective. The authors recently found that grasping was not relatively more disrupted than reaching in people with acute hemiparesis. They now extend this work to the recovery of reach versus grasp. Methods. Hemiparetic subjects were tested acutely, after 90 days, and then after 1 year poststroke, and a control group was evaluated once. Using kinematic techniques, subjects were studied performing reach and reach-to-grasp movements. The authors quantified 3 characteristics of performance for each movement: speed, accuracy, and efficiency, where an efficient movement was defined as a movement directly to the target without extraneous or abnormally circuitous movements. To evaluate the relative deficits and recovery in reach versus grasp, performance measures were converted to z scores using control group means and standard deviations. Results. The authors’ results showed that, starting with small deficits in speed acutely, both reach speed and grasp speed improved over time. Deficits in accuracy were greater in the reach than the grasp acutely, and these deficits lessened such that by the 90-day time point, the relative accuracy of the 2 movements was the same. In contrast, deficits in efficiency were greater in the grasp than the reach acutely, and grasp efficiency did not recover. The majority of recovery in reaching and grasping occurred by the 90-day time point, with little change occurring between the 90-day and 1-year time points. Conclusions. The authors hypothesize that, in chronic hemiparesis, purposeful movements requiring distal control may be more impaired than purposeful movements requiring proximal control, not because of the initial lesion, but because, over the course of recovery, spared components of the descending motor systems may be able to compensate for the accuracy deficits in reaching (proximal control) but not the efficiency deficits in grasping (distal muscular control).

Relationships between Sensorimotor Impairments and Reaching Deficits in Acute Hemiparesis

To determine the relationships between sensorimotor impairments and upper extremity reaching performance during the acute phase of stroke and to determine which, if any, measures of sensorimotor impairment can predict variance in reaching performance during this phase. Methods. Sensorimotor impairments of upper extremity (UE) strength, active range of motion, isolated movement control, light touch sensation, joint position sense, spasticity, and shoulder pain were evaluated in a group of 46 individuals with acute hemiparesis (mean time since insult = 9.2 days). Subjects performed a reaching task to a target placed on their affected side. Three-dimensional kinematic analyses were used to assess reaching speed, accuracy, and efficiency. Forward stepwise multiple linear regression analyses were used to determine which impairment was the best predictor of variance in reaching performance. Results. Measures of UE strength predicted the largest proportion of variance in the speed, accuracy, and efficiency of forward reaching. Isolated movement control, somatosensory deficits, and elbow spasticity predicted smaller amounts of variance in reaching performance. Conclusions. The authors’ data show that deficits in strength appear to be the most influential sensorimotor impairment associated with limited reaching performance in subjects with acute hemiparesis.

Upper Extremity Muscle Activation during Recovery of Reaching in Subjects with Post-stroke Hemiparesis

OBJECTIVE To investigate upper extremity muscle activation and recovery during the first few months after stroke. METHODS Subjects with hemiparesis following stroke were studied performing a reaching task at an acute time point (mean=9 days post-stroke) and then again at a subacute time point (mean=109 days post-stroke). We recorded kinematics and electromyographic activity of six upper extremity muscles. RESULTS At the acute time point, the hemiparetic group had delayed muscle onsets, lower modulation ratios, and higher relative levels of muscle activation (%MVIC) during reaching than controls. From the acute to the subacute time points, improvements were noted in all three variables. By the subacute phase, muscle onsets were similar to controls, while modulation ratios remained lower than controls and %MVIC showed a trend toward being greater in the hemiparetic group. Changes in muscle activation were differentially related to changes in reaching performance. CONCLUSIONS Our data show that improvements in muscle timing and decreases in the relative level of volitional activation may underlie improved reaching performance in the early months after stroke. SIGNIFICANCE Given that stroke is one of the leading causes of persistent physical disability, it is important to understand how the ability to activate muscles changes during the early phases of recovery after injury.

Patterns of Lumbar Region Movement During Trunk Lateral Bending in 2 Subgroups of People With Low Back Pain

Background and Purpose The movement system impairment (MSI) system is one proposed system for classifying low back pain (LBP) problems. Prior clinical data and observations for the MSI system suggest that different LBP subgroups demonstrate different patterns of movement during clinical tests, such as trunk lateral bending (TLB). The purpose of this study, therefore, was to examine the validity of the observation that lumbar region (LR) movement patterns during TLB are different between 2 subgroups of people with LBP: lumbar rotation with extension (Rotation With Extension) and lumbar rotation (Rotation). Subjects Participants were 44 people (28 men and 16 women; age [X̄±SD], 28.5±8.4 years) with chronic or recurrent LBP. Methods Each participants LBP problem was classified with the MSI system. Kinematic variables were measured, and LBP symptoms were recorded during the TLB test. Results People in the 2 LBP subgroups demonstrated different patterns of LR movement during TLB. People in the Rotation With Extension subgroup displayed an asymmetric (right versus left) pattern of LR movement across the TLB movement, whereas people in the Rotation subgroup displayed a symmetric pattern of LR movement. Equal proportions of people in the 2 subgroups reported an increase in symptoms with the TLB test. Discussion and Conclusion The patterns of LR movement across the TLB movement were different in 2 subgroups of people with LBP. The difference in the LR movement patterns between subgroups may be an important factor to consider in specifying the details of the interventions for these 2 LBP problems.

Effect of position and alteration in synergist muscle force contribution on hip forces when performing hip strengthening exercises

BACKGROUND Understanding the magnitude and direction of joint forces generated by hip strengthening exercises is essential for appropriate prescription and modification of these exercises. The purpose of this study was to evaluate hip joint forces created across a range of hip flexion and extension angles during two hip strengthening exercises: prone hip extension and supine hip flexion. METHODS A musculoskeletal model was used to estimate hip joint forces during simulated prone hip extension and supine hip flexion under a control condition and two altered synergist muscle force conditions. Decreased strength or activation of specific muscle groups was simulated by decreasing the modeled maximum force values by 50%. For prone hip extension, the gluteal muscle strength was decreased in one condition and the hamstring muscle strength in the second condition. For supine hip flexion, the strength of the iliacus and psoas muscles was decreased in one condition, and the rectus femoris, tensor fascia lata, and sartorius muscles in the second condition. FINDINGS The hip joint forces were affected by hip joint position and partially by alterations in muscle force contribution. For prone hip extension, the highest net resultant force occurred with the hip in extension and the gluteal muscles weakened. For supine hip flexion, the highest resultant forces occurred with the hip in extension and the iliacus and psoas muscles weakened. INTERPRETATION Clinicians can use this information to select exercises to provide appropriate prescription and pathology-specific modification of exercise.

Classification, treatment and outcomes of a patient with lumbar extension syndrome.

The purpose of the current report is to describe the classification, treatment, and outcomes of a patient with lumbar extension syndrome. The patient was a 40-year-old female with an 18-month history of mechanical low back pain (LBP). The patient reported a history of daily, intermittent pain (mean intensity of 9/10) that limited her ability to sit, stand, walk, and sleep, as well as perform work-related activities. Symptom-provoking movement and alignment impairments associated with the direction of lumbar extension were identified and modification of these impairments consistently resulted in a decrease in pain. Treatment was provided in 3 sessions over a 2-month period. Priority of treatment was to train the patient to restrict lumbar extension-related alignments and movements during symptom-provoking functional activities. Exercises to address the extension-related impairments also were prescribed. The primary change in outcome was a decrease in the mean intensity (2 months: 2/10; 6 months: 1/10) and frequency of pain (2 months: decreased pain with standing and walking; 6 months: additional decrease with sitting, standing and walking). She also reported a decreased duration and number of LBP episodes. Classification directed treatment resulted in improvement in short and long term impairment and functional-level outcomes.

The immediate effect of passive scapular elevation on symptoms with active neck rotation in patients with neck pain.

ObjectiveTo examine the effect of elevating the scapulae on symptoms during neck rotation. MethodsA retrospective analysis of clinical records was conducted. One physical therapist examined 46 patients with neck pain (30 women, 16 men; mean age 45.89+14.39 y) using a standardized examination. Patients had a long-standing history of neck pain with a moderate level of symptoms and disability. Reports of symptoms were obtained in 2 scapulae position conditions: a patient-preferred scapulae position and a passively elevated scapulae position. ResultsIn the patient-preferred positions, 29 (63%) of the 46 patients reported an increase in symptoms with neck rotation in at least one direction. In the scapulae elevated position, a significant percentage of patients reported a decrease in symptoms with neck rotation, right (82%) and left (76%) (both comparisons, P≤0.01). ConclusionsPassive elevation of the scapulae resulted in a decrease in symptoms with right and left neck rotation in the majority of patients. These findings are important because they indicate that neck symptoms can be immediately improved within the context of the examination. Such information potentially can be used to assist in directing intervention.

The Human Movement System: Our Professional Identity

The 2013 House of Delegates of the American Physical Therapy Association adopted a vision statement that addresses the role of physical therapy in transforming society through optimizing movement. The accompanying guidelines address the movement system as key to achieving this vision. The profession has incorporated movement in position statements and documents since the early 1980s, but movement as a physiological system has not been addressed. Clearly, those health care professions identified with a system of the body are more easily recognized for their expertise and role in preventing, diagnosing, and treating dysfunctions of the system than health professions identified with intervention but not a system. This perspective article provides a brief history of how leaders in the profession have advocated for clear identification of a body of knowledge. The reasons are discussed for why movement can be considered a physiological system, as are the advantages of promoting the system rather than just movement. In many ways, a focus on movement is more restrictive than incorporating the concept of the movement system. Promotion of the movement system also provides a logical context for the diagnoses made by physical therapists. In addition, there is growing evidence, particularly in relation to musculoskeletal conditions, that the focus is enlarging from pathoanatomy to pathokinesiology, further emphasizing the timeliness of promoting the role of movement as a system. Discussion also addresses musculoskeletal conditions as lifestyle issues in the same way that general health has been demonstrated to be clearly related to lifestyle. The suggestion is made that the profession should be addressing kinesiopathologic conditions and not just pathokinesiologic conditions, as would be in keeping with the physical therapists role in prevention and as a life-span practitioner.