Functional Movement Disorder
Conditions
Keywords
functional movement disorder, sense of agency, judgment of agency
Brief summary
Functional movement disorders (FMD) are among the most common neurological conditions seen in clinical practice, yet they are poorly understood and often misdiagnosed. Impaired self-agency, the sense of controlling one's actions, is a key feature of FMD. Studies using functional MRI have shown reduced activation and connectivity in the right inferior parietal lobule, a region associated with agency. The sense of agency consists of two components: the feeling of agency, which is an implicit, low-level sense of control over voluntary actions, and the judgment of agency, which is the conscious attribution of actions to oneself. While the feeling of agency is often measured using intentional binding tasks, judgment of agency is assessed using self-reported scales. While studies have explored intentional binding as a measure of implicit agency in FMD, few have systematically investigated judgment of agency. This study aims to fill this gap by introducing a novel approach that quantitatively evaluates judgment of agency in FMD patients using action-outcome latencies as an objective metric.
Detailed description
Objective: The objective of this study is to investigate the differences between patients with FMD and healthy controls in perceiving visual and auditory outcomes as consequences of their actions. This will be assessed by measuring their judgment of agency through action-outcome latencies.
Interventions
None listed
Sponsors
Western University, Canada
Study design
Observational model
CASE_CONTROL
Time perspective
CROSS_SECTIONAL
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
Yes
Inclusion criteria
for patients: Inclusion criteria for patients: 1. Diagnosed with clinically definite functional movement disorder 2. Age \>18 years. 3. Able to read and understand English. Inclusion criteria for healthy subjects: 1. Age \>18 years. 2. Able to read and understand English
Exclusion criteria
for patients: 1. Moderate to severe action tremor in the dominant hand limiting the ability to perform the task. 2. Upper limb peripheral neuropathy. 3. Unable to read and understand English.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| SA Index | Day 1 | Latencies values corresponding to positive ("YES") responses will be extracted. SA (Sense of Agency) Index will be computed by multiplying the 90th percentile latencies by the number of positive responses below this latency threshold and then dividing the result by the total number of responses (positive, negative and unsure) occurring below the same threshold. |
| Latencies | Day 1 | The 90th percentile of latency values among trials with positive ("YES") responses. |
Countries
Canada
Contacts
CONTACTAditya Murgai, MBBS MD DM
Outcome results
None listed