Reliability and validity of the range of motion scale (ROMS) in patients with abnormal postures

Sustained abnormal postures (i.e., fixed dystonia) are the most frequently reported motor abnormalities in complex regional pain syndrome (CRPS), but these symptoms may also develop after peripheral trauma without CRPS. Currently, there is no valid and reliable measurement instrument available to measure the severity and distribution of these postures. The range of motion scale (ROMS) was therefore developed to assess the severity based on the possible active range of motion of all joints (arms, legs, trunk, and neck), and the present study evaluates its reliability and validity.

Inter- and intra-rater reliability of the ROMS was determined in 16 patients with abnormal sustained postures, who were videotaped following a standard video protocol in a university hospital. The recordings were rated by a panel of international experts. In addition, 30 patients were clinically tested with both the Burke-Fahn-Marsden (BFM) scale as well as the ROMS to assess construct validity.

Inter-rater reliability for total ROMS scores showed an intra-class correlation coefficient (ICC) of 0.85. The majority of the scores for the separate joints (13 out of 18) demonstrated an almost perfect agreement with ICCs ranging from 0.81 to 0.94; of the other items, one showed fair, one moderate, and three substantial agreement. The ICCs for the intra-rater reliability ranged from moderate to almost perfect (0.68-0.98). Spearman's correlation coefficients between corresponding body areas as measured with the ROMS or BFM were all above 0.82.

The ROMS is a reliable and valid instrument to evaluate the severity and distribution of sustained abnormal postures.