Test-Retest Reliability of the Neuromuscular Recovery Scale

Abstract Objective To determine the test-retest reliability of the Neuromuscular Recovery Scale (NRS), a measure to classify lower extremity and trunk recovery of individuals with spinal cord injury (SCI) to typical preinjury performance of functional tasks without use of external and behavioral compensation. Design Multicenter observational study. Setting Five outpatient rehabilitation clinics. Participants Physical therapists (N=13), trained and competent in conducting NRS, rated outpatients with SCI (N=69) using the NRS. Testing occurred on 2 days, separated by 24 to 48 hours, on the same patient by the same therapist. Interventions Not applicable. Main Outcome Measures Spearman rank correlation coefficients to compare NRS results. The NRS scores of motor performance were based on normal, preinjury function on 11 items: 4 treadmill-based items (standing and stepping), 7 overground/mat items (sitting, sit-up, reverse sit-up, trunk extension, sit to stand, standing, walking). Results Test-retest reliability was very strong for the NRS items. Ten of the 11 items exhibited Spearman correlation coefficients ≥.92, and lower bounds of the 95% confidence intervals (CIs) for these items met or exceeded .83. The exception was stand retraining (ρ=.84; 95% CI, .68–.96). The test-retest reliability of the measurement model-derived summary score was very strong (ρ=.99; 95% CI, .96–.99). Conclusions The NRS had excellent test-retest reliability when conducted by trained therapists in adults with chronic SCI across all levels of injury severity. All raters had undergone standardized training in use of the NRS. The minimal requirement of training to achieve test-retest reliability has not been established.