Reliability of the Modified Tardieu Scale and the Modified Ashworth Scale in adult patients with severe brain injury: a comparison study

Objective: To assess and to compare the reliability of the Modified Tardieu Scale with the Modified Ashworth Scale in patients with severe brain injury and impaired consciousness. Design: Cross-sectional observational comparison study. Setting: An early rehabilitation centre for adults with neurological disorders. Subjects: Thirty patients with impaired consciousness due to severe cerebral damage of various aetiologies. Measurement protocol: Four experienced physical therapists rated each patient in a randomized order once daily for two consecutive days. Shoulder, elbow, wrist, hip, knee and ankle spasticity were assessed by the use of Modified Tardieu Scale and Modified Ashworth Scale data collection procedures. Main outcome measures: Test-retest and inter-rater reliability (kappa = kappa value) of the Modified Tardieu Scale and the Modified Ashworth Scale. Results: The test-retest reliability of the Modified Ashworth Scale was moderate to good (kappa = 0.47-0.62) and of the Modified Tardieu Scale moderate to very good (kappa = 0.52-0.87). Test-retest reliability was significantly higher within the Modified Tardieu Scale in comparison with the Modified Ashworth Scale (Z > 1.96; p < 0.05) except for shoulder extensor and internal rotator muscles (Z< 1.96; p > 0.05). Although inter-rater reliability of both scales was poor to moderate (Modified Ashworth Scale: kappa = 0.16-0.42; Modified Tardieu Scale: kappa = 0.29-0.53), significantly higher K-values were revealed with the Modified Tardieu Scale for all tested muscle groups (Z > 1,96; p < 0.05) except for wrist extensors (Z< 1.96; p > 0.05). Conclusion: In patients with severe brain injury and impaired consciousness the Modified Tardieu Scale provides higher test-retest and inter-rater reliability compared with the Modified Ashworth Scale and may therefore be a more valid spasticity scale in adults.