Objective: In the current study we explored the clinical utility of Stop Signal Reaction Time (SSRT) as a diagnostic marker for functional cervical dystonia (FCD).
Background: FCD is characterized as a movement abnormality resembling adult-onset idiopathic cervical dystonia (CD). Treatment outcomes are often unsatisfactory due to inaccurate diagnosis. This limitation may be addressed through identification of a disease marker which can differentiate FCD and CD. Previous studies have demonstrated that the ability to stop an ongoing movement is impaired in adult-onset cervical dystonia. This was quantitatively estimated through a stop signal paradigm from which an index is derived called ‘Stop Signal Reaction Time’ (SSRT), first proposed by Logan and Cowan 1984. This index was further modified by our group using a Bayesian statistical approach to make it more reproducible, which we have termed optimal combination SSRT (ocSSRT).
Method: In this cross-sectional study, we recruited 14 FCD and 20 CD patients from the movement disorders and psychiatry outpatient departments, and 30 healthy subjects. ocSSRT was measured with a portable device programmed to execute and analyse a stop signal task. The participants were asked to release the button as quickly as possible after illumination of the GO (green) LED and abort the ongoing movement when the GO signal was followed by a STOP (red) signal.
Results: CD patients demonstrated a significantly prolonged ocSSRT compared to FCD patients (373±76, 285±80 p<0.05). There was no significant difference in ocSSRT between FCD patients and healthy controls (285±80, 248±64 p = 0.396). Median reaction time did not show a significant difference between CD and FCD patients. The area under the ROC curve comparing ocSSRT between FCD and CD was 0.775.
Conclusion: These preliminary results indicate that stop signal reaction time could be a potential marker in differentiating FCD from CD.
To cite this abstract in AMA style:
SB. Banerjee, SC. Choudhury, AR. Roy, PK. Jakati, PB. Basu, SM. Mukherjee, JG. Ganguly, NS. Singh, MRB. Baker, SNB. Baker, HK. Kumar. Stop signal reaction time: A promising Diagnostic marker for Functional Cervical Dystonia [abstract]. Mov Disord. 2023; 38 (suppl 1). https://www.mdsabstracts.org/abstract/stop-signal-reaction-time-a-promising-diagnostic-marker-for-functional-cervical-dystonia/. Accessed June 14, 2025.« Back to 2023 International Congress
MDS Abstracts - https://www.mdsabstracts.org/abstract/stop-signal-reaction-time-a-promising-diagnostic-marker-for-functional-cervical-dystonia/