A Williams Andrews

Distribution of muscle strength impairments following stroke

Objective: The purpose of this study was to quantify the distribution of strength impairments soon after stroke. We were specifically interested in differences in impairments between proximal and distal actions, flexion and extension actions, and upper and lower limb actions. Design: We conducted a retrospective chart review of strength scores of patients with acute stroke. Setting: Inpatient rehabilitation unit. Subjects: Forty-eight patients with a primary diagnosis of stroke underwent initial testing on admission; 31 of the same patients underwent final testing prior to discharge. Main outcome measures: The strength of eight muscle actions was assessed bilaterally using hand-held dynamometry. Force measurements obtained were expressed in newtons and as a percentage of normal. Results: Strength was impaired bilaterally but more so on the side contralateral to the brain lesion. Distal muscle actions were less impaired than proximal muscle actions on the stronger side. Extension actions were less impaired than flexion actions bilaterally but primarily in the upper limbs. Upper limb actions were less impaired than lower limb actions only on the stronger side. Conclusions: With a few exceptions, our results do not support common clinical assumptions regarding the distribution of strength impairments following stroke.

Relationships between impairments in strength of limb muscle actions following stroke.

To examine the relationships between impairments in limb muscle strength soon after stroke, a secondary analysis of a data base of 48 patients with stroke was undertaken. Measurements of isometric muscle strength obtained bilaterally from eight muscle actions and recorded in the data base were retrieved for analysis. Most of the strength measures correlated significantly with one another. The measures of muscle strength showed high internal consistency in each limb, on each side, and over-all. Principal components analysis and cluster analysis indicated that the closest relationships were between muscle actions of the upper limb contralateral to the stroke (the “paretic” side), limb muscle actions of the side ipsilateral to the stroke (the “nonparetic” side), and muscle actions of the lower limbs. These findings may reflect the organization of the central nervous system following stroke.

Minimal Clinically Important Difference for Comfortable Speed as a Measure of Gait Performance in Patients Undergoing Inpatient Rehabilitation after Stroke

[Purpose] The purpose of this retrospective study was to determine the minimal clinically important difference for comfortable gait speed for patients with stroke. [Subjects] Data were analyzed from 35 patients undergoing inpatient rehabilitation. [Methods] Two characteristics of gait were measured, assistance required and comfortable gait speed. Patients were grouped as either experiencing or not experiencing a decrease of 2 or more levels of assistance required over the course of rehabilitation. Receiver operating characteristic curve analysis was used to identify the change in gait speed that best differentiated between patients who did and did not experience the requisite decrease in assistance required for gait. [Results] Twenty-one patients decreased 2 or more levels of assistance whereas 14 did not. Walking speed increased significantly more in the group who experienced a decrease in assistance of at least 2 levels. The receiver operating characteristic curve analysis showed a change in walking speed of 0.13 m/s best distinguished between patients who did versus did not experience a reduction in assistance required. [Conclusion] An improvement in gait speed of 0.13 m/s or more is clinically important in patients with stroke.

Discharge function and length of stay for patients with stroke are predicted by lower extremity muscle force on admission to rehabilitation.

Objective: We sought to determine the relative value of lower extremity muscle strength as a predictor of discharge function and length of stay of patients with stroke. Methods: We studied 72 patients undergoing inpatient rehabilitation after a stroke and documented their outcome using length of stay and function [as measured by the Func tional Independence Measure (FIM) at discharge]. Results: Knee-extension force and the total force of four lower extremity muscle actions (hip flexion, knee extension, knee flexion, and ankle dorsiflexion) were correlated significantly with discharge FIM and length of stay. The correlations involving the actions of the weaker side were higher. Admission FIM was also correlated significantly with discharge FIM and length of stay. Previous stroke and age were correlated significantly with discharge FIM but not length of stay. The set of variables offering the best explanation of discharge FIM (R = 0.867) was admission FIM, admission FIM squared, age, and total force of the weaker side. The set of variables offering the best explanation of length of stay (R = 0.812) was knee- extension force of the weaker side squared, admission FIM, admission FIM squared, and age. Conclusions: Lower extremity muscle force of the weaker side on admission has value as a predictor of function at discharge and length of stay for patients with stroke admitted to inpatient rehabilitation. Muscle force, therefore, is a reasonable target of measurement and treatment. Knowledge of muscle force on admission can assist clini cians, patients, families, and others to anticipate patient outcomes after rehabilitation.

Relationship between impairments and gait performance after stroke: a summary of relevant research

Abstract This review was undertaken to describe the relationship between clinical measures of impairment and gait performance in patients with stroke. Twenty-four studies were analysed. Four major gait variables and five major impairments were identified. Strength of the paretic lower extremity and standing balance were found consistently to be correlated with gait performance. These variables therefore represent appropriate targets for evaluation and treatment in patients with stroke.

Relative Strength of Seven Upper Extremity Muscle Groups in Hemiparetic Stroke Patients

This study was undertaken to determine whether or not some upper extremity muscle groups are affected more than others after a stroke, and subsequently to identify which muscle group was impaired the most in each of three pairs of opposing muscle groups. The static force production (strength) of seven upper extremity muscle groups was assessed bilaterally in 69 patients, all of whom had suffered an initial stroke. When compared with the values obtained in the nonparetic extremity, the relative strength was not consistent across the seven paretic upper extremity muscle groups. Paretic elbow extensor strength was preserved more than elbow flexor strength. In the paretic shoulder, internal rotator and extensor strengths were preserved more than external rotator and abductor strengths. The muscle strength imbalance, which tends to exist between the paretic shoulder depressors and elevators, and its possible influence on other problems that can occur in the hemiparetic shoulder are discussed.

Association of Rehabilitation Intensity for Stroke and Risk of Hospital Readmission

Background Little is known about the use of rehabilitation in the acute care setting and its impact on hospital readmissions. Objective The objective of this study was to examine the association between the intensity of rehabilitation services received during the acute care stay for stroke and the risk of 30-day and 90-day hospital readmission. Design A retrospective cohort analysis of all acute care hospitals in Arkansas and Florida was conducted. Methods Patients (N=64,065) who were admitted for an incident stroke in 2009 or 2010 were included. Rehabilitation intensity was categorized as none, low, medium-low, medium-high, or high based on the sum and distribution of physical therapy, occupational therapy, and speech therapy charges within each hospital. Cox proportional hazards regression was used to estimate hazard ratios, controlling for demographic characteristics, illness severity, comorbidities, hospital variables, and state. Results Relative to participants who received the lowest intensity therapy, those who received higher-intensity therapy had a decreased risk of 30-day readmission. The risk was lowest for the highest-intensity group (hazard ratio=0.86; 95% confidence interval=0.79, 0.93). Individuals who received no therapy were at an increased risk of hospital readmission relative to those who received low-intensity therapy (hazard ratio=1.30; 95% confidence interval=1.22, 1.40). The findings were similar, but with smaller effects, for 90-day readmission. Furthermore, patients who received higher-intensity therapy had more comorbidities and greater illness severity relative to those who received lower-intensity therapy. Limitations The results of the study are limited in scope and generalizability. Also, the study may not have adequately accounted for all potentially important covariates. Conclusions Receipt of and intensity of rehabilitation therapy in the acute care of stroke is associated with a decreased risk of hospital readmission.

Standards for judgments of unilateral impairments in muscle strength.

A secondary analysis of a data base of isometric strength measures from 136 asymptomatic adults (50–79 years) was conducted to estimate the normal difference between dominant and nondominant side strengths. Measures of strength obtained by hand-held dynamometry from 13 muscle actions were expressed as a ratio, dominant side strength:nondominant side strength. The ratios indicated that the dominant side was stronger on average but that the normal range of differences between sides could reach 23.2 to 40.2%, depending on the action. The findings do not provide much support for the convention of using a 10% difference in strength between sides to designate impairment.