"The development of a Unified Dyskinesia Rating Scale will provide a critical research tool for any future clinical trial," says Dr. Christopher G. Goetz, Director of Movement Disorders of Rush University Medical Center, who along with Dr. John G. Nutt, Oregon Health and ScienceUniversity, are working to develop the rating scale.
Goetz says that without a comprehensive scale, current clinical trials make use of many disparate scales that rely on different types of clinical assessments. "The lack of a Unified Dyskinesia Rating Scale makes it difficult to compare results across research studies and decreases the robustness of clinical trials testing dyskinesia treatments."
When it comes to measuring a new therapy's effects on dyskinesias — the involuntary, uncontrollable, and excessive movements that are a common side effect of drugs used to treat Parkinson's Disease— different clinicians observing the same evidence can potentially come to very different conclusions. No standardized and comprehensive tool exists to make the judgment easier.
"Dyskinesias have such a large impact on patients' day-to-day lives that nearly every Parkinson's clinical trial measures them — even trials that don't explicitly involve a dyskinesia therapy," said Katie Hood, the Michael J. Fox Foundation's (MJFF) vice president of research programs, one of the two research funding agencies. "But the resulting body of evidence lacks cohesion because there is no common set of metrics for reporting on dyskinesias. Practitioners agree on the strong need for a 'common language' if we are to successfully address this difficult complication of Parkinson's treatment."
Dyskinesiascan be lurching, dance-like or jerky and are distinct from the rhythmic tremor commonly associated with Parkinson's DISEASE.. Hood says they are a research priority for the MJFF because patients often cite them as one of the most disabling aspects of living with the disease.
Goetz and Nutt have already consolidated elements of existing dyskinesia scales into a working draft of the unified scale. Funding from the MJFF will allow this draft to be finalized, tested and presented to the movement disorder community.
The validation studies will be done in several steps. The researchers must first test the consistency and reliability of the scale. To do this, they will videotape examinations of about 70 Parkinson's patients with varying dyskinesia severity levels. The videotapes will be distributed to clinician raters along with a preliminary version of the scale, which the clinicians will use to rate the taped patients' dyskinesias. Goetz and Nutt will look for variations in the raters' scores on these identical cases to refine the scale and the instructions for using it.
The physicians will then prepare a teaching tape for widespread distribution to clinicians.
The teaching tape will include segments featuring at least four patients at each level of dyskinesia severity. The teaching tape will have an "answer key" — ratings made by three internationally recognized dyskinesia experts. Clinicians learning to use the scale will be able to watch the tape, make their own assessments, and then compare their ratings to the experts'.
The researchers plan to present the Unified Dyskinesia Rating Scale, together with all instructions and teaching tools for its use, to the movement disorder community by early 2008.
The Michael J. Fox Foundation (MJFF) has awarded the researchers $84,000 and EMD Pharmaceutic has given $50,000 in funding.
Contact: Mary Ann Schultz
Rush University Medical Center