Abstract

Functional neurological disorders (FNDs), also known as conversion disorder, are unexplained neurological symptoms unrelated to a neurological cause. The disorder is common, yet poorly understood. The symptoms are experienced as involuntary but have similarities to voluntary processes. Here we studied intention awareness in FND. A total of 26 FND patients and 25 healthy volunteers participated in this functional magnetic resonance study using Libet's clock. FND is characterized by delayed awareness of the intention to move relative to the movement itself. The reporting of intention was more precise, suggesting that these findings are reliable and unrelated to non-specific attentional deficits. That these findings were more prominent with aberrant positive functional movement symptoms rather than negative symptoms may be relevant to impairments in timing for an inhibitory veto process. Attention towards intention relative to movement was associated with lower right inferior parietal cortex activity in FND, a region early in the processing of intention. During rest, aberrant functional connectivity was observed with the right inferior parietal cortex and other motor intention regions. The results converge with observations of low inferior parietal activity comparing involuntary with voluntary movement in FND, emphasizing core deficiencies in intention. Heightened precision of this impaired intention is consistent with Bayesian theories of impaired top-down priors that might influence the sense of involuntariness. A primary impairment in voluntary motor intention at an early processing stage might explain clinical observations of slowed effortful voluntary movement, heightened self-directed attention and underlie functional movements. These findings further suggest novel therapeutic targets.

Highlights

  • Functional neurological disorder (FND), or conversion disorder, refers to neurological symptoms in the absence of a neurological condition (American Psychiatric Association, 2013)

  • An early crucial study hypothesized that a disturbance of volition might underlie FND (Spence et al 2000)

  • We aimed to explore awareness of voluntary motor intention in a larger sample of FND patients with mixed symptoms and healthy volunteers (HV)

Read more

Summary

Introduction

Functional neurological disorder (FND), or conversion disorder, refers to neurological symptoms in the absence of a neurological condition (American Psychiatric Association, 2013). The disorder is common (Carson et al 2000) and physically debilitating as Parkinson’s disease, with greater impact on mental health and quality of life (Anderson et al 2007; Voon et al 2016). Functional neurological disorders (FNDs), known as conversion disorder, are unexplained neurological symptoms unrelated to a neurological cause.

Objectives
Methods
Results
Discussion
Conclusion
Full Text
Published version (Free)

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 call