Action Outcome Latencies as a Measure of Sense of Agency in Functional Movement Disorders.

Action Outcome Latencies as a Measure of Sense of Agency in Functional Movement Disorders.

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.

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.

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.

Exclusion criteria for healthy subjects:

1. Unable to read and understand English.