A teaching film, video library and online certification for the Unified Huntington's Disease Rating Scale Total Motor Score

Background: Clinical assessment of motor symptoms in Huntington's Disease (HD) is commonly performed using the Unified Huntington's Disease Rating Scale-Total Motor Score (UHDRS-TMS) (HSG 1996). Clinical diagnosis of HD is based on the presence of characteristic motor symptoms in the UHDRS-TMS. Therefore results of clinical trials are limited by (1) possible subjective error of raters (inter-rater and intra-rater variability), (2) the limited sensitivity of the categorical rating scale (non-continuous measure), and (3) insensitivity in pre-manifest subjects (de Boo et al., 1998).

Objective: In order to increase sensitivity and power of future clinical trials using the UHDRS-TMS as outcome measure, standardization of the application and rating of the UHDRS motor exam should be supported by a teaching film and library providing clinical samples of patients in all stages of HD and performance of raters should be assessed.

Methods: Using the service of a professional film team (Polaris Pictures, Hungary), the UHDRS-TMS exam of 165 patients with HD was filmed at several participating European Huntington's Disease Network (EHDN) sites. Each patient video was rated online by 6 members of an international expert rater panel (42 members from the EHDN and the Huntington Study Group). A teaching film explaining how to administer and how to rate the UHDRS-TMS sub-items was edited. Samples for different grades of disability were selected based on the ratings of the expert panel. A library providing fast access to samples was developed for use in clinics or for training and teaching purposes. Annual certification for UHDRS-TMS raters is offered at www.euro-hd.net requiring successful rating of 3 patient videos within ranges defined by an expert panel of the EHDN Motor Phenotype Working Group.

Results: EHDN UHDRS-TMS certification is now mandatory for motor raters in currently recruiting multicenter trials worldwide (e.g., the ACR-16 trial, REGISTRY, TRACK-HD, HART-Study). In 2008 more than 140 raters were certified.

Conclusion: Video based training programs should be used to improve standardization of test application and inter-rater variability of clinical rating scales. Online certification systems can be established and find acceptance in the field. Prospective evaluation of this system is in progress.

Acknowledgment: This project was funded by a grant to RR from the High-Q-Foundation and Cure Huntington's Disease Initiative Foundation, New York, and by the EHDN.