Chinese validation of the Rasch-Built Overall Amyotrophic Lateral Sclerosis Disability Scale.

BACKGROUND AND PURPOSE

The Rasch-Built Overall Amyotrophic Lateral Sclerosis Disability Scale (ROADS) was developed using Rasch methodology. This scale has been demonstrated as a reliable outcome measure of amyotrophic lateral sclerosis (ALS) trials. To date, there are no similar interval-weighted scales to assess disability in ALS patients. The current study aimed to validate a Chinese version of the ROADS via Rasch methodology.

METHODS

The Chinese version of the ROADS was obtained through a standardized forward-backward translation and cultural adaptation. ALS patients were recruited from the Department of Neurology of Peking University Third Hospital in Beijing, China to complete the ROADS and the revised ALS Functional Rating Scale (ALSFRS-R). Overall, 254 participants with ALS finished the Chinese scale. Rasch analysis was performed on the ROADS for validation and the ALSFRS-R for comparison.

RESULTS

The Chinese version of the ROADS was modified according to the statistical results. A final 28-question scale was constructed that fulfilled all the requirements of the Rasch model with proper validity and reliability. Furthermore, the ROADS showed improved item targeting compared to the ALSFRS-R. Conversely, the ALSFRS-R did not fit the Rasch model expectations due to misfit values and disordered thresholds for all 12 items.

CONCLUSIONS

The Chinese adaptation of the ROADS is a linearly weighted scale that specifically captures overall disability in ALS patients. This scale indicates a wider range of item difficulties and better responsiveness than the ALSFRS-R. The ROADS could be used as a valuable tool for use in ALS trials and in the clinic in Chinese settings.