Reliability of the Modified Ashworth Scale and Modified Tardieu Scale in patients with spinal cord injuries

Abstract

Study design: Psychometrics study.

Objectives: To assess the reliability of the Modified Ashworth Scale (MAS) and Modified Tardieu Scale (MTS) in patients with spinal cord injuries (SCIs).

Setting: Inpatient rehabilitation clinics at two state hospitals.

Methods: The study included 65 participants aged between 18 and 88 years with SCI with spasticity. All participants were at least 6 months after injury and had an American Spinal Injury Association Impairment Scale grade of A-D. The MAS and MTS scores were collected from the right hip adductor and hip extensor muscles, right knee extensor and knee flexor muscles and right plantar flexor muscles. Each participant was assessed twice by two experienced physiatrists 1 week apart. The raters were blinded to each other's scores.

Results: Inter-rater and test-retest agreement for the MAS scores (κ=0.531-0.774) was moderate to substantial. Inter-rater and test-retest agreement for the MTS X scores (κ=0.692-0.917) was substantial to almost perfect. Inter-rater reliability and test-retest reliability of the MTS R2-R1 was excellent (intra-class correlation coefficient (ICC) 0.874-0.973, confidence interval (CI): 0.79-0.98) for all muscles tested. Inter-rater reliability of the MTS R2 for the hip adductor and knee extensor muscles was poor (ICC 0.248, CI: -0.00 to 0.47 and ICC 0.094, CI: -0.16 to 0.34, respectively). The test-retest reliability of the MTS R2 was also poor for the knee extensor muscles (ICC 0.318, CI: -0.06 to 0.53).

Conclusion: MAS has adequate reliability for determining lower-extremity spasticity in patients with SCI. The demonstration of excellent inter-rater reliability and test-retest reliability of the MTS R2-R1 suggests its utility as a complementary tool for informing treatment decisions in patients with SCI.