Marenka Smit

University of Groningen | RUG · Department of Developmental Neurology

Background Dystonia is a rare movement disorder, in which patients suffer from involuntary twisting movements or abnormal posturing. Next to these motor symptoms, patients have a high prevalence of psychiatric comorbidity, suggesting a role for serotonin in its pathophysiology. This study investigates the percentage of DNA methylation of the gene e...

Adult-onset dystonia can be acquired, inherited or idiopathic. The dystonia is usually focal or segmental and for a limited number of cases causal treatment is available. In recent years, rapid developments in neuroimmunology have led to increased knowledge on autoantibody-related dystonias. At the same time, genetic diagnostics in sequencing techn...

GTP-cyclohydrolase deficiency in dopa-responsive dystonia (DRD) patients impairs the biosynthesis of dopamine, but also of serotonin. The high prevalence of non-motor symptoms suggests involvement of the serotonergic pathway. Our study aimed to investigate the serotonergic system in vivo in the brain of`DRD patients and correlate this to (non-)moto...

Introduction In dystonia, dopaminergic alterations are considered to be responsible for the motor symptoms. Recent attention for the highly prevalent non-motor symptoms suggest also a role for serotonin in the pathophysiology. In this study we investigated the dopaminergic, serotonergic and noradrenergic metabolism in blood samples of dystonia pati...

Improved care for people with dystonia presents a number of challenges. Major gaps in knowledge exist with regard to how to optimize the diagnostic process, how to leverage discoveries in pathophysiology into biomarkers, and how to develop an evidence base for current and novel treatments. These challenges are made greater by the realization of the...

Objectives Non‐motor symptoms (NMS) are commonly present along with motor impairment in patients with cervical dystonia (CD) and have a significant impact on health‐related quality of life (HRQoL). However, the prevalence of NMS and their association with dystonia are still unclear. The aim of our study was to assess the prevalence of depression, a...

Purpose: The pathophysiology of cervical dystonia (CD) is thought to be related to changes in dopamine and serotonin levels in the brain. We performed a double-blind trial with escitalopram (selective serotonin reuptake inhibitor; SSRI) in patients with CD. Here, we report on changes in dopamine D2/3 receptor (D2/3R), dopamine transporter (DAT) and...

Background: Myoclonus-dystonia (M-D) due to a pathogenic variant of SGCE is an autosomal dominant inherited movement disorder. Apart from motor symptoms, psychiatric disorders are highly prevalent in patients with M-D. Previous studies suggest, but never tested directly, that the type of psychiatric disorder differs between dystonia syndromes, pro...

Background A previous study reported a dramatic mismatch in objectively detected and self-reported tremor duration in patients with functional tremor. As these findings have an important and widespread impact in both clinical care and research, we conducted a validation study with a longer study duration and a larger sample of patients. Methods Fo...

PurposeAlterations of the central serotonergic system have been implicated in the pathophysiology of dystonia. In this molecular imaging study, we assessed whether altered presynaptic serotonin transporter (SERT) binding contributes to the pathophysiology of cervical dystonia (CD), concerning both motor and non-motor symptoms (NMS).Methods We asses...

Objective: Trials for additional or alternative treatments for cervical dystonia (CD) are scarce since the introduction of botulinum neurotoxin (BoNT). We performed the first trial to investigate whether dystonic jerks/tremor in patients with CD respond to the selective serotonin reuptake inhibitor (SSRI) escitalopram. Methods: In a randomised,...

Background: Cervical dystonia (CD) is often accompanied by depressive symptoms, anxiety, and jerks/tremor. The dopamine transporter (DAT) binding is related with both depressive symptoms and jerks/tremor in CD. Serotonergic and dopaminergic systems are closely related. As serotonin is involved in the pathophysiology of psychiatric symptoms and jer...

Background: In patients with GTP-cyclohydrolase deficient dopa-responsive dystonia (DRD) the occurrence of associated non-motor symptoms (NMS) is to be expected. Earlier studies report conflicting results with regard to the nature and severity of NMS. The aim of our study was to investigate the prevalence of psychiatric disorders, sleep problems,...

Introduction: Functional movement disorders are accompanied by a high occurrence of psychopathology and cause serious impairments in quality of life. However, little is known about this in patients with functional jerks and no comparison has been made between patients with functional jerks and organic myoclonus. This case control study compares th...

PurposeCervical dystonia (CD) is associated with tremor/jerks (50%) and psychiatric complaints (17–70%). The dopaminergic system has been implicated in the pathophysiology of CD in animal and imaging studies. Dopamine may be related to the motor as well as non-motor symptoms of CD. CD is associated with reduced striatal dopamine D2/3 (D2/3) recepto...

Background Evidence suggests that non‐motor symptoms (NMS) are the most important predictors of decreased health‐related quality of life (HR‐QoL) in patients with cervical dystonia (CD). In this study, we evaluate an NMS screening list and examine the influence of motor symptoms and NMS on HR‐QoL. Methods In 40 patients with CD, the frequency of N...

[This corrects the article on p. 165 in vol. 7, PMID: 27733842.].

Background Nonmotor symptoms (NMS) are highly prevalent in cervical dystonia (CD). In general, fatigue and sleep are important NMS that determine a decreased health‐related quality of life (HR‐QoL), but their influence in CD is unknown. The authors systematically investigated fatigue, excessive daytime sleepiness (EDS), and sleep quality in patient...

Cervical dystonia is a movement disorder which affects daily living of many patients. In clinical practice several unmet treatment needs remain open. This article focusses on the four main aspects of treatment. We describe existing and emerging treatment approaches for cervical dystonia, including botulinum toxin injections, surgical therapy, manag...

Introduction: The aim of this study was to systematically investigate the prevalence of psychiatric disorders and factors influencing health-related quality of life (HR-QoL) in cervical dystonia (CD) patients, in the context of objective dystonia motor severity. Methods: We studied 50 CD patients and 50 matched healthy controls. Psychiatric asse...

Dystonia is a hyperkinetic movement disorder characterized by sustained or intermittent muscle contractions. Emerging data describe high prevalences of non-motor symptoms, including psychiatric co- morbidity, as part of the phenotype of dystonia. Basal ganglia serotonin and serotonin-dopamine interactions gain attention, as imbalances are known to...

Dystonia is a hyperkinetic movement disorder characterized by sustained or intermittent muscle contractions. Emerging data describe high prevalences of non-motor symptoms, including psychiatric co-morbidity, as part of the phenotype of dystonia. Basal ganglia serotonin and serotonin-dopamine interactions gain attention, as imbalances are known to b...