Marapin, R.S. (Ramesh) (2019) Altered posterior midline activity in patients with hyperkinetic functional movement disorders: a resting-state fMRI study. thesis, Medicine.
Full text available on request.Abstract
Functional movement disorders (FMD) are clinical neurological syndromes comprising weakness or hyperkinetic movement disorders that are genuine but incongruent with recognized neural correlates. Effective treatments have yet to be established and most people fail to substantially improve under current treatment regimes. Notably, FMD have a dramatic impact on disability and quality of life, comparable to Parkinson’s Disease and Multiple Sclerosis. Taken together, this yields an unfavorable prognosis for patients with FMD, and thus warrants further investigation into the mechanisms underlying FMD. Currently, the pathophysiological basis of FMD remains poorly understood. Recently, a Bayesian model was proposed to explain the genesis of FMD and posits that functional symptoms are the result of pathological prior experiences that are modulated by alterations of sense of agency and attention dysregulation. These altered mechanisms are pertinent in patients with FMD as they experience a lack of control over their movements and often direct too much attention towards their body. Restingstate fMRI provides the opportunity to study brain network function in patients while at rest. Against this background, we reasoned that examining the functioning of brain networks associated with attention and sense of agency in FMD patients can provide valuable insight into its underlying mechanisms. Therefore, we aimed to study the central executive network, salience network, and default mode network in a homogenous population of FMD patients consisting of hyperkinetic functional movement disorders (hFMD) using resting-state fMRI. Resting-state fMRI data from seventeen patients with hFMD and seventeen age-, sex-, and education matched healthy controls was investigated. Independent component analysis was used to examine the central executive network, salience network, and default mode network. Frequency distribution of network signal fluctuations, intra- and internetwork functional connectivity were investigated. Symptom severity was measured using the Clinical Global Impression-Severity scale. Compared with healthy controls, patients with hFMD had significantly decreased power of lower-range (0.01-0.10 Hz) frequency fluctuations and significantly increased power of upperrange (0.11-0.25 Hz) frequency fluctuations in a precuneus and posterior cingulate cortex component of the default mode network (FDR-corrected P<0.05). In patients with hFMD, symptom severity was correlated with reduced intranetwork functional connectivity in the cuneus and the anterior part of the inferior parietal lobule. No significant group differences were found for internetwork functional connectivity. In conclusion, given the contributions of the precuneus and posterior cingulate cortex to attention shifting and sense of agency, the hFMD-related functional alterations in these regions provide support for the concept that attentional dysregulation and impaired sense of agency are fundamental disturbances in these patients. The association between symptom severity and reduced intranetwork functional connectivity in the cuneus and the inferior parietal lobule further supports this idea. These findings might contribute to new perspectives and avenues for future studies and to the growing conceptualization of FMD.
| Item Type: | Thesis (Thesis) |
|---|---|
| Supervisor name: | Supervisor: and Gelauff, J.M. and Faculty supervisor: and Koning-Tijssen, prof. dr. de and Department of Neurology, University Medical Center Groningen |
| Faculty: | Medical Sciences |
| Date Deposited: | 25 Jun 2020 10:44 |
| Last Modified: | 25 Jun 2020 10:44 |
| URI: | https://umcg.studenttheses.ub.rug.nl/id/eprint/599 |
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