Responsiveness of the Neuromuscular Recovery Scale During Outpatient Activity-Dependent Rehabilitation for Spinal Cord Injury.

BACKGROUND: The Neuromuscular Recovery Scale (NRS) was developed by researchers and clinicians to functionally classify people with spinal cord injury (SCI) by measuring functionally relevant motor tasks without compensation. Previous studies established strong interrater and test-retest reliability and validity of the scale. OBJECTIVE: To determine responsiveness of the NRS, a version including newly added upper-extremity items, in an outpatient rehabilitation setting. METHODS: Assessments using the NRS and 6 other instruments were conducted at enrollment and discharge from a locomotor training program for 72 outpatients with SCI classified as American Spinal Injury Association Impairment Scale grades A to D (International Standards for Neurological Classification of Spinal Cord Injury). Mixed-model t statistics for instruments were calculated and adjusted for confounding factors (eg, sample size, demographic variables) for all patients and subgroups stratified by injury level and/or severity. The resulting adjusted response means (ARMs) and 95% confidence intervals (CIs) were used to determine responsiveness, and significant differences between instruments were identified with pairwise comparisons. RESULTS: The NRS was significantly responsive for SCI outpatients (ARM = 1.05; CI = 0.75-1.35). Changes in motor function were detected across heterogeneous groups. Regardless of injury level or severity, the responsiveness of the NRS was equal to, and often significantly exceeded, the responsiveness of other instruments. CONCLUSIONS: The NRS is a responsive measure that detects change in motor function during outpatient neurorehabilitation for SCI. There is potential utility for its application in randomized controlled trials and as a measure of clinical recovery across diverse SCI populations.

Foot placement variability as a walking balance mechanism post-spinal cord injury.

BACKGROUND: Spinal cord injury affects walking balance control, which necessitates methods to quantify balance ability. The purposes of this study were to 1) examine walking balance through foot placement variability post-injury; 2) assess the relationship between measures of variability and clinical balance assessments; and 3) determine if spatial parameter variability might be used as a clinical correlate for more complex balance measurements. METHODS: Ten persons with spinal cord injury walked without devices on a split-belt treadmill at self-selected speeds. Ten healthy controls walked at 0.3 and 0.6m/s for comparison. Variability of step width and length, anteroposterior and mediolateral foot placements relative to center-of-mass, and margin-of-stability were calculated. Clinical assessments included Berg Balance Scale and Dynamic Gait Index. FINDINGS: Participants with spinal cord injury demonstrated significantly different variability in all biomechanical measures compared to controls (P ≤ 0.007). Berg Balance Scale scores were significantly inversely associated with step length as well as anteroposterior and mediolateral foot placement variability (P ≤ 0.05). Dynamic Gait Index scores were significantly inversely associated with mediolateral foot placement variability (P ≤ 0.05). Participants with spinal cord injury showed significant correlations between spatial parameter variability and all other measures (P ≤ 0.005), except between step length and margin-of-stability (P=0.068); controls revealed fewer correlations. INTERPRETATION: Persons post-spinal cord injury exhibit an abnormal amount of stepping variability when challenged to walk without devices, yet preserve the ability to avoid falling. When complex laboratory measures of variability are unavailable clinically, spatial parameter variability or standardized balance assessments may be plausible indicators of walking balance control.