Abstract
Background: In functional movement disorders, explicit movements are impaired, while implicit movements are preserved. Furthermore, there is evidence that the sense of agency is abnormal.Aim: We aimed to investigate how motor responses and sense of agency were affected by subliminal or supraliminal cues in people with functional movement disorders.Methods: Twenty-three people with a functional movement disorder and 26 healthy controls took part in a subliminal and supraliminal priming experiment which investigated reaction times, choice and sense of agency. Participants pressed a left or right arrow key in response to an imperative left or right pointing arrow. Either key could be pressed in response to bidirectional arrows. The imperative arrow was preceded by a small left or right pointing prime arrow, that was non-predictive (50% correct) and was presented in either subliminal or supraliminal conditions. The participant's response caused the appearance of a colored circle and they rated the degree of control they felt over its appearance (sense of agency). The circle's color depended on whether their response was congruent or incongruent with the prime arrow direction. After exclusion, 19 participants remained in each group.Results: Prime-compatible responses led to faster reaction times in both the subliminal and supraliminal condition. Subliminal prime-compatible responses were chosen more frequently in the free choice condition. The sense of agency did not depend on prime-response congruency. There were no significant differences in any of these measures between the two groups.Conclusion: With non-predictive cues, reaction times, choices, and the sense of agency remain normal in people with functional movement disorders, for both subliminal and supraliminal primes. The findings suggest that it is not so much conscious awareness of the movement, but rather conscious motor preparation that is detrimental to motor function in functional movement disorders.
Highlights
Sense of agency refers to the sense of controlling one’s own actions, and, through them, events in the outside world
functional movement disorders (FMD) share many characteristics of voluntary movements: they manifest with attention and improve or disappear with distraction; voluntary movements interfere with them as exemplified by the phenomenon of “entrainment” [2]; and some FMDs are preceded by a “Bereitschaftspotential” on electroencephalography, which is typically present before self-paced voluntary movements and absent in involuntary movements [3]
Clearly state that their abnormal movements are involuntary. Could it be that the abnormal movements in FMD are voluntary movements in terms of the physiological pathway that generates them, but are anomalous in terms of the conscious experience that accompanies their generation? previous studies, both of intentional binding [4] and of the experience of conscious intention [5], have indicated an abnormal sense of agency in FMD
Summary
Sense of agency refers to the sense of controlling one’s own actions, and, through them, events in the outside world. It is the conscious experience that one has volitional or willed control over one’s own actions and can influence the environment [1]. There are several reasons for suspecting an abnormality of the sense of agency in functional movement disorders (FMD). Clearly state that their abnormal movements are involuntary. Could it be that the abnormal movements in FMD are voluntary movements in terms of the physiological pathway that generates them, but are anomalous in terms of the conscious experience that accompanies their generation? Previous studies, both of intentional binding [4] and of the experience of conscious intention [5], have indicated an abnormal sense of agency in FMD. There is evidence that the sense of agency is abnormal
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
