It's tricky: Rating alleviating maneuvers in cervical dystonia

Area of Science:

• Neurology
• Clinical Assessment
• Movement Disorders

Background:

• The sensory trick (alleviating maneuver, AM) is a key feature in managing cervical dystonia (CD).
• Previous analyses questioned the clinimetric properties of the AM item in the Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS-2).
• Hypothesized sources of error include insufficient demonstration time, inadequate baseline CD severity, and reversed rater scoring.

Purpose of the Study:

• To investigate and identify sources of error in quantifying the sensory trick's effect in CD using the TWSTRS-2.
• To test strategies for mitigating these identified errors.
• To provide guidance for future research on sensory trick assessment in CD.

Main Methods:

• Video recordings and TWSTRS-2 ratings were used for 185 patients with isolated CD.
• Ratings were performed by one site rater and a panel of five video raters.
• Hypotheses regarding testing time, CD severity, and rater scoring conventions were tested.

Main Results:

• 12% of patients lacked sufficient time to demonstrate their AM.
• 12% had CD severity too mild for confident AM effect rating.
• Isolated instances of reversed scoring by raters were identified.

Conclusions:

• Addressing identified sources of error in AM assessment and rating improves its utility in measuring CD motor severity.
• The AM's efficacy is significant for diagnosis and understanding pathophysiology.
• Modifications for assessing AMs in future CD research are recommended.