Interrater and intrarater reliability of the Modified Ashworth Scale in children with hypertonia.

Purpose: The Modified Ashworth Scale (MAS) is a six-point scale used to assess spasticity. This study assessed interrater and intrarater reliability of the MAS for children with hypertonia.

Methods: Five raters participated in this examination of interrater and intrarater reliability. The study included 17 children who showed hypertonus. Elbow flexor, hip adductor, quadriceps, hamstring, gastrocnemius, and soleus muscles were tested bilaterally.

Results: Results demonstrated good interrater reliability (intraclass correlation coefficient [ICC] >0.75) for elbow flexors and hamstrings and poor interrater reliability (ICC <0.50) for other muscles. Intrarater scores were good (ICC >0.75) for hamstrings and moderate (ICC = 0.50 to 0.75) for other muscles.

Conclusion: Interrater reliability of the MAS may be lower than desired for clinical use for muscles other than hamstrings and elbow flexors, and intrarater reliability may also be lower than desired for muscles other than the hamstrings.