Relationship between motor FIM and muscle strength in lower cervical-level spinal cord injuries

Study design: Retrospective analysis. Objectives: The objectives of this research were to, in subjects with lower cervical spinal cord injury (SCI), examine the relationship between strength of muscle groups as measured by the manual muscle test (MMT) and function (reflected as burden of care) as measured by individual functional independence measure (FIM) motor tasks, and investigate the extent to which MMT scores explain the variance of the motor FIM scores. Setting: Acute rehabilitation hospitals, Boston, MA, USA. Methods: Retrospective pilot study of 20 in-patients, age 18 - 62 years, with an SCI between C5 and C7. Discharge demographic variables, MMT and motor FIM scores were analyzed. Descriptive statistics, Spearman's rank correlation coefficients, stepwise regressions were performed. Results: MMT scores for elbow flexion followed by shoulder flexion and wrist extension correlated with the greatest number of FIM tasks. MMT scores explained some part of the variance in the eight of 12 motor FIM tasks. In six of eight tasks, one key muscle explained a large portion of the variance. Conclusion: Key muscles relative to FIM tasks can be identified. These findings may help focus therapeutic interventions aimed at achievement in these tasks.