Motor and non-motor determinants of health-related quality of life in young dystonia patients

Focal dystonia in musicians, a literature review

BACKGROUND

Musician's focal dystonia (mFD) is a rare, neurological, task-specific disorder that mainly affects the upper extremity (especially the hands) and generally appears as a painless muscular incoordination that can mark the end of a musician's professional career. The present literature review intends to highlight the current understanding of musician's focal dystonia, its underlying neural mechanisms and the role of prevention and treatment in physiotherapy, psychotherapy and other fields as occupational therapy.

PURPOSE

The aim of the present literature review was to gain an overview of mFD in the medical, psychological and physical therapy literature and investigate what strategies for diagnosis and rehabilitation are available today.

STUDY DESIGN

The present article is a literature review, based on the search for full-text publications with the goal of comparing the main strategies for mFD rehabilitation and prevention presented in the literature.

METHODS

This literature review compared many relevant papers and studies available in literature today for mFD epidemiology, neural mechanisms, treatment and prevention, to discuss what we know today and highlight the aspects that can still be enhanced in the future.

RESULTS

According to our results, current literature gives a good understanding of mFD epidemiology, but further studies are needed to fully comprehend the neurological aspects and develop more rehabilitation strategies, especially in the psychological field. Our research also highlighted the need for a multidisciplinary approach that considers both physical and psychological aspects.

CONCLUSIONS

Physical rehabilitation strategies are helpful but, considering the amount of psychological aspects involved in mFD, a holistic approach should be considered and developed in the future. Finally, prevention must have a primary role in mFD treatment, raising awareness around it and, possibly, avoiding its development.

Content and readability of patient educational materials about neuromodulation for childhood movement disorders

PURPOSE

To assess content and readability of online patient educational materials (PEMs) for paediatric deep brain stimulation (DBS) and intrathecal baclofen (ITB).

METHODS

A content analysis of PEMs identified from top children's hospitals, institutions affiliated with published neuromodulation research, and DBS and ITB device manufacturers was conducted. PEM content was analysed using a predetermined framework. Readability was assessed using the Simple Measure of Gobbledygook (SMOG).

RESULTS

Of 109 PEMs (72 DBS; 37 ITB) identified, most (77 (71%)) originated in the United States. More ITB PEMs (27 (73%)) contained specific paediatric information than DBS PEMs (16 (22%)). PEMS more frequently described benefits (DBS: 92%; ITB: 89%) than risks (DBS: 49%; ITB: 78%). Frequent content included pre- and post-operative care, procedural details, and device information. Less common content included long-term lifestyle considerations, alternatives, patient experiences, and financial details. Median readability of PEMs was 13.2 (interquartile range [IQR]: 11.4-14.45) for DBS and 11.8 (IQR: 11-12.9) for ITB.

CONCLUSIONS

Available ITB and DBS PEMs often miss important broader details of the treatments, and have additional shortcomings such as poor readability scores. Our findings highlight need for more holistic content within neuromodulation PEMs, improved accessibility, and more balanced representation of risks and benefits.

Deep brain stimulation in dystonia: The added value of neuropsychological assessments

Deep brain stimulation (DBS) of the internal globus pallidus (GPi) is a recognized treatment for medication-refractory dystonia. Problems in executive functions and social cognition can be part of dystonia phenotypes. The impact of pallidal DBS on cognition appears limited, but not all cognitive domains have been investigated yet. In the present study, we compare cognition before and after GPi DBS. Seventeen patients with dystonia of various aetiology completed pre- and post-DBS assessment (mean age 51 years; range 20-70 years). Neuropsychological assessment covered intelligence, verbal memory, attention and processing speed, executive functioning, social cognition, language and a depression questionnaire. Pre-DBS scores were compared with a healthy control group matched for age, gender and education, or with normative data. Patients were of average intelligence but performed significantly poorer than healthy peers on tests for planning and for information processing speed. Otherwise, they were cognitively unimpaired, including social cognition. DBS did not change the baseline neuropsychological scores. We confirmed previous reports of executive dysfunctions in adult dystonia patients with no significant influence of DBS on cognitive functioning in these patients. Pre-DBS neuropsychological assessments appear useful as they support clinicians in counselling their patients. Decisions about post-DBS neuropsychological evaluations should be made on a case-by-case basis.

Non-Motor Symptoms and Quality of Life in Patients with PRRT2-Related Paroxysmal Kinesigenic Dyskinesia

Background

Monoallelic pathogenic variants of PRRT2 often result in paroxysmal kinesigenic dyskinesia (PKD). Little is known about health-related quality of life (HrQoL), non-motor manifestations, self-esteem, and stigma in patients with PKD.

Objectives

We investigated non-motor symptoms and how they related to HrQoL in a genetically homogeneous group of PRRT2-PKD patients. We paid special attention to perceived stigmatization and self-esteem.

Methods

We prospectively enrolled 21 consecutive PKD patients with a pathogenic variant of PRRT2, and 21 healthy controls matched for age and sex. They were evaluated with dedicated standardized tests for non-motor symptoms, HrQoL, anxiety, depression, stigma, self-esteem, sleep, fatigue, pain, and psychological well-being.

Results

Patients reported an alteration of the physical aspects of HrQoL, regardless of the presence of residual paroxysmal episodes. Non-motor manifestations were frequent, and were an important determinant of the alteration of HrQoL. In addition, patients perceived a higher level of stigmatization which positively correlated with a delay in diagnosis (ρ = 0.615, P = 0.003) and the fear of being judged (ρ = 0.452, P = 0.04), but not with the presence of paroxysmal episodes (ρ = 0.203, P = 0.379).

Conclusions

Our findings have important implications for care givers concerning patient management and medical education about paroxysmal dyskinesia. PRRT2-PKD patients should be screened for non-motor disorders in routine care. A long history of misdiagnosis may play a role in the high level of perceived stigmatization. Improving knowledge about diagnostic clues suggestive of PKD is mandatory.

Early Onset Dystonia: Complaints about Executive Functioning, Depression and Anxiety

Early Onset Dystonia (EOD) is thought to result from basal ganglia dysfunction, structures also involved in non-motor functions, like regulation of behavior, mood and anxiety. Problems in these domains have been found in proxy-reports but not yet in self-reports of EOD patients. The main questions are whether proxy-reports differ from those of patients and how problems relate to everyday social functioning. Subjective complaints about executive problems (BRIEF) and symptoms of depression and anxiety (CBCL) were obtained through a cross-sectional questionnaire study conducted on 45 EOD patients. Scores were in the normal range in patients and proxies. Proxy-rated behavior regulation was correlated with the estimated number of friends and quality of relations. Proxy-reported scores of depression correlated with the quality of relations and were higher than self-reports of adolescent/young adult patients. EOD patients and proxies do not seem to experience problematic regulation of behavior, mood and anxiety. Still, our study revealed two important aspects: (1) all measures were related to the estimated quality of relations with others, relating questionnaires to everyday social functioning; (2) proxies reported more symptoms of depression than patients. This may indicate overestimation by proxies or higher sensitivity of proxies to these symptoms, implying underestimation of problems by patients.

Elective and Emergency Deep Brain Stimulation in Refractory Pediatric Monogenetic Movement Disorders Presenting with Dystonia: Current Practice Illustrated by Two Cases

BACKGROUND

Dystonia is characterized by sustained or intermittent muscle contractions, leading to abnormal posturing and twisting movements. In pediatric patients, dystonia often negatively influences quality of life. Pharmacological treatment for dystonia is often inadequate and causes adverse effects. Deep brain stimulation (DBS) appears to be a valid therapeutic option for pharmacoresistant dystonia in children.

METHODS

To illustrate the current clinical practice, we hereby describe two pediatric cases of monogenetic movement disorders presenting with dystonia and treated with DBS. We provide a literature review of similar previously described cases and on different clinical aspects of DBS in pediatric dystonia.

RESULTS

The first patient, a 6-year-old girl with severe dystonia, chorea, and myoclonus due to an ADCY5 gene mutation, received DBS in an elective setting. The second patient, an 8-year-old boy with GNAO1-related dystonia and chorea, underwent emergency DBS due to a pharmacoresistant status dystonicus. A significant amelioration of motor symptoms (65% on the Burke-Fahn-Marsden Dystonia Rating Scale) was observed postoperatively in the first patient and her personal therapeutic goals were achieved. DBS was previously reported in five patients with ADCY5-related movement disorders, of which three showed objective improvement. Emergency DBS in our second patient resulted in the successful termination of his GNAO1-related status dystonicus, this being the eighth case reported in the literature.

CONCLUSION

DBS can be effective in monogenetic pediatric dystonia and should be considered early in the disease course. To better evaluate the effects of DBS on patients' functioning, patient-centered therapeutic goals should be discussed in a multidisciplinary approach.

Needs and Perceptions of Patients With Dystonia During the COVID-19 Pandemic: A Qualitative Framework Analysis of Survey Responses From Italy

Introduction:

The COVID-19 pandemic and its countermeasures have created changes in both life and healthcare. With the prioritization of COVID-19-related management, the risks and experiences of patients suffering from rare conditions, such as dystonia, during the pandemic remain understudied.

Materials and Methods

Using a framework analysis of a nationwide qualitative online survey, we sought to explore the perspectives of patients with dystonia on their clinical assistance and possible unmet needs during the first pandemic wave. An online survey consisting of 37 items (such as demographic characteristics, dystonia-related features, neurological service provision, therapeutic relationship with the neurologist, perceptions related to virus infection, perceptions about healthcare-related needs, work-related questions, requesting information, and seeking support during the pandemic) was carried out using both close and open-ended questions.

Results

Responses from 62 participants were collected, with most of them from the red zones in Italy, where they were confined indoors. Social isolation was a relevant stressor. Motor and non-motor symptoms increased with detrimental consequences for patients' job and daily functionality. Outpatient clinics and rehabilitation sessions were temporarily shut down, and even telephone/mail support was sparse. Despite efforts, patients felt alone in dealing with dystonia.

Conclusion

The first wave of the pandemic and its related restrictions had detrimental consequences for people living with dystonia, and their relevant needs remained unmet. These findings may contribute to implementing remedial healthcare provisions in this pandemic or in future pandemics.

Exploitation of Thermal Sensitivity and Hyperalgesia in a Mouse Model of Dystonia

Neuropathic pain is characterized by mechanical allodynia and thermal hyperalgesia to heat, and it affects some 20% of European population. Patients suffering from several neurologic diseases experience neuropathic pain, often finding no relief in therapy. Transgenic mice expressing the gene encoding the human mutant (hMT) or the human wild-type (hWT) torsin A represent a preclinical model of DYT1 dystonia which is the most common form of early-onset inherited dystonia. Baseline thermal sensitivity and hyperalgesia to heat have never been studied in models of dystonia. Therefore, the aim of this research has been to characterize thermal sensitivity in baseline conditions and hyperalgesia to heat after the induction of neuropathic pain through the spinal nerve ligation (SNL) model in mice overexpressing human wild-type and mutated torsin A in comparison to non-transgenic C57BL/6 mice. According to our results, the paw withdrawal latency time to heat in the Hargreaves’ test is significantly lower in the hMT mice (Kruskal–Wallis test = 6.933; p = 0.0312*; hMT vs. hWT p = 0.0317*). On the other hand, no significant differences in SNL-induced thermal hyperalgesia was found among the three strains (Friedman test = 4.933; p = 0.1019). Future studies are needed to better understand the role of torsin A in sensory processing of heat stimuli.

Personality Profile in Focal Hand Dystonia: A Cross-Sectional Study

It has been suggested that focal hand dystonia (FHD) should be viewed as a neuropsychiatric disorder rather than as a pure movement disorder. We aimed to compare the personality factors that are common to people with FHD and evaluate how personality factors could affect the functionality of the upper limbs and community participation. We conducted a cross-sectional case-control study in which 12 people with FHD were matched with 12 age and gender matched healthy control participants. The Big Five Questionnaire; the Quick Disabilities, Arm, Shoulder, and Hand questionnaire; and the Jebsen-Taylor Test of Hand Function were used as assessment measures. Control of emotions was the only variable for which a significant difference was found, with participants with FHD displaying lesser control. Correlations were not observed between different personality profiles, the functionality of the upper limbs and the perceived participation of people with FHD in activities of daily living. People with FHD may present with low emotional stability, but this does not have a negative impact on the functionality of the upper limbs and activities of daily living. These findings have clinical implications to be considered for interventions, as they suggest that personality aspects, such as extraversion, may not predict for better functionality and perceived participation in activities of daily living.

High prevalence of self-reported non-motor symptoms and lack of correlation with motor severity in adult patients with idiopathic isolated dystonia

BACKGROUND

Although abnormal movements and postures are the hallmark of dystonia, non-motor symptoms (NMS) are common and negatively affect quality of life.

OBJECTIVES

The aim of this study was to screen dystonia patients for NMS and analyze their association with clinical parameters, including motor disability.

METHODS

Adult patients with idiopathic isolated dystonia were interviewed and examined. Dystonia severity was evaluated with the Fahn-Marsden Dystonia Rating Scale and the presence of NMS was assessed using a list of 29 complaints.

RESULTS

A hundred and two patients (63.7% female) were enrolled. Dystonia began after 20 years of age in 61.8% and was focal or segmental in 82.8% of patients. Only eight patients (7.8%) had no NMS and 59.8% reported more than five. The most prevalent NMS were pain (72.5%) and anxiety (63.7%), followed by difficulty recalling information (44.1%), sadness/anhedonia (41.2%), and difficulty falling asleep (38.2%). No correlation was found between the total number of NMS and dystonia severity (p = 0.18) or regular botulinum toxin use (p = 0.66). The majority of NMS domains correlated with each other.

CONCLUSIONS

Our results confirm a high prevalence of NMS among dystonia patients, even in those with mild motor disability. The pathophysiology of NMS in dystonia remains to be completely understood.

Dystonia genes functionally converge in specific neurons and share neurobiology with psychiatric disorders

Dystonia is a neurological disorder characterized by sustained or intermittent muscle contractions causing abnormal movements and postures, often occurring in absence of any structural brain abnormality. Psychiatric comorbidities, including anxiety, depression, obsessive-compulsive disorder and schizophrenia, are frequent in patients with dystonia. While mutations in a fast-growing number of genes have been linked to Mendelian forms of dystonia, the cellular, anatomical, and molecular basis remains unknown for most genetic forms of dystonia, as does its genetic and biological relationship to neuropsychiatric disorders. Here we applied an unbiased systems-biology approach to explore the cellular specificity of all currently known dystonia-associated genes, predict their functional relationships, and test whether dystonia and neuropsychiatric disorders share a genetic relationship. To determine the cellular specificity of dystonia-associated genes in the brain, single-nuclear transcriptomic data derived from mouse brain was used together with expression-weighted cell-type enrichment. To identify functional relationships among dystonia-associated genes, we determined the enrichment of these genes in co-expression networks constructed from 10 human brain regions. Stratified linkage-disequilibrium score regression was used to test whether co-expression modules enriched for dystonia-associated genes significantly contribute to the heritability of anxiety, major depressive disorder, obsessive-compulsive disorder, schizophrenia, and Parkinson's disease. Dystonia-associated genes were significantly enriched in adult nigral dopaminergic neurons and striatal medium spiny neurons. Furthermore, 4 of 220 gene co-expression modules tested were significantly enriched for the dystonia-associated genes. The identified modules were derived from the substantia nigra, putamen, frontal cortex, and white matter, and were all significantly enriched for genes associated with synaptic function. Finally, we demonstrate significant enrichments of the heritability of major depressive disorder, obsessive-compulsive disorder and schizophrenia within the putamen and white matter modules, and a significant enrichment of the heritability of Parkinson's disease within the substantia nigra module. In conclusion, multiple dystonia-associated genes interact and contribute to pathogenesis likely through dysregulation of synaptic signalling in striatal medium spiny neurons, adult nigral dopaminergic neurons and frontal cortical neurons. Furthermore, the enrichment of the heritability of psychiatric disorders in the co-expression modules enriched for dystonia-associated genes indicates that psychiatric symptoms associated with dystonia are likely to be intrinsic to its pathophysiology.

Effect of Gabapentin in a Neuropathic Pain Model in Mice Overexpressing Human Wild-Type or Human Mutated Torsin A

BACKGROUND

DYT1 dystonia is the most common form of early-onset inherited dystonia, which is caused by mutation of torsin A (TA) belonging to the "ATPases associated with a variety of cellular activities" (AAA + ATPase). Dystonia is often accompanied by pain, and neuropathic pain can be associated to peripherally induced movement disorder and dystonia. However, no evidence exists on the effect of gabapentin in mice subjected to neuropathic pain model overexpressing human normal or mutated TA.

METHODS

Mice subjected to L5 spinal nerve ligation (SNL) develop mechanical allodynia and upregulation of the α2δ-1 L-type calcium channel subunit, forming a validated experimental model of neuropathic pain. Under these experimental conditions, TA is expressed in dorsal horn neurons and astrocytes and colocalizes with α2δ-1. Similar to this subunit, TA is overexpressed in dorsal horn 7 days after SNL. This model has been used to investigate (1) basal mechanical sensitivity; (2) neuropathic pain phases; and (3) the effect of gabapentin, an α2δ-1 ligand used against neuropathic pain, in non-transgenic (NT) C57BL/6 mice and in mice overexpressing human wild-type (hWT) or mutant (hMT) TA.

RESULTS

In comparison to non-transgenic mice, the threshold for mechanical sensitivity in hWT or hMT does not differ (Kruskal-Wallis test = 1.478; p = 0.4777, although, in the latter animals, neuropathic pain recovery phase is delayed. Interestingly, gabapentin (100 mg/Kg) reduces allodynia at its peak (occurring between post-operative day 7 and day 10) but not in the phase of recovery.

CONCLUSIONS

These data lend support to the investigation on the role of TA in the molecular machinery engaged during neuropathic pain.

Non-Motor Manifestations in Idiopathic Dystonia with Focal Onset - A Pilot Study

Recent studies emphasize an increased prevalence of non-motor symptoms in idiopathic dystonia with focal onset (IDFO), but their pathophysiological relationship is not clear. We aimed to identify the prevalence of depression and neurocognitive impairment in a group of patients with idiopathic dystonia with focal onset and their impact on the patients' quality of life. This study represents a component of an ongoing research project - GENDYS. From the database of this project, we selected 48 patients 56.62+/-14.16 years old who have been examined clinically and using specific scales: Patient Health Questionnaire-9 (for depression), Montreal Cognitive Assessment - MoCA (for cognitive impairment), and a 5-degree analog scale for subjective perception of the severity of the disease. We conducted a descriptive cross-sectional study on patients with depression and cognition evaluated by the above-mentioned scales. We also performed a nested case-control analysis on 20 IDFO patients with and without at least moderate depression matched for age and gender; the cut-offs for depression were PHQ-9 score ≥10 and PHQ9 <5, for the depression group and the control group, respectively. The cut-off for MoCA was 26 points. 22 IDFO patients (46%) had depression; 54.5% of IDFO patients with depression had cognitive impairment, indicating a slight trend of increased cognitive impairment in those with depression compared to those without; the perception of the severity of disease was the greatest in patients with depression. Depression is more prevalent in patients with IDFO and is associated with a worse perception of the disease severity.

Reliability and Validity of the Dyskinesia Impairment Scale in Children and Young Adults with Inherited or Idiopathic Dystonia

Background: The Dyskinesia Impairment Scale (DIS) is a new assessment scale for dystonia and choreoathetosis in children and youth with dyskinetic cerebral palsy. Today, the Burke–Fahn–Marsden Dystonia Rating Scale (BFM) is mostly used to assess dystonia in children with inherited dystonia. The aim of this study was to assess reliability and validity of the DIS in children and youth with inherited or idiopathic dystonia. Methods: Reliability was measured by (1) the intraclass correlation coefficients (ICCs) for inter-rater and test-retest reliability, as well as (2) standard error of measurement (SEM) and minimal detectable difference (MDD). For concurrent validity of the DIS-dystonia subscale, the BFM was administered. Results: In total, 11 males and 9 females (median age 16 years and 7 months, range 6 to 24 years) were included. For inter-rater reliability, the ICCs for the DIS total score and the dystonia and choreoathetosis subscale scores were 0.83, 0.87, and 0.71, respectively. For test-retest reliability, the ICCs for the DIS total score and the dystonia and choreoathetosis subscale scores were 0.95, 0.88, and 0.93, respectively. The SEM and MDD for the total DIS were 3.98% and 11.04%, respectively. The Spearman correlation coefficient between the dystonia subscale and the BFM was 0.88 (p < 0.01). Conclusions: Good to excellent inter-rater, test-retest reliability, and validity were found for the total DIS and the dystonia subscale. The choreoathetosis subscale showed moderate inter-rater reliability and excellent test-retest reliability. The DIS may be a promising tool to assess dystonia and choreoathetosis in children and young adults with inherited or idiopathic dystonia.

Non-motor Symptoms in Chinese Patients With Isolated Generalized Dystonia: A Case-Control Study

Background: Previous studies have indicated that non-motor symptoms are primary problems in focal dystonia, but limited data are available about non-motor problems and their correlation with motor severity in generalized dystonia (GD).

Methods: In the present study, we performed a case-control study and enrolled isolated inherited or idiopathic GD patients and age- and sex-matched healthy controls (HC). Clinical characteristics, motor symptoms, non-motor problems, including psychiatric co-morbidity, sleep problems, fatigue, and quality of life (QoL) were assessed in both groups using various rating scales and assessments.

Results: Thirty-three patients with GD and 33 controls were enrolled. Significant higher scores on depression and anxiety (p < 0.001) were shown in GD compared with HC, whereas the frequency of obsessive-compulsive disorders approached that of HC (p = 0.238). Patients with GD also had significantly higher Pittsburg Sleep Quality Index (PSQI) and fatigue scores than HC, whereas no difference was observed in excessive daytime somnolence. In GD, QoL was more impaired, with statistically lower scores in both physical and mental components. Psychiatric rating scales did not correlate to motor severity or disease duration but might influence quality of sleep. Subgroup analysis suggests non-motor manifestations differ with different etiologies in GD.

Conclusion: This study suggests that non-motor symptoms in GD, such as psychiatric problems, are likely to be primary determinants not correlated to motor severity, which may also affect quality of sleep and fatigue.

Plasticity and dystonia: a hypothesis shrouded in variability

Studying plasticity mechanisms with Professor John Rothwell was a shared highlight of our careers. In this article, we discuss non-invasive brain stimulation techniques which aim to induce and quantify plasticity, the mechanisms and nature of their inherent variability and use such observations to review the idea that excessive and abnormal plasticity is a pathophysiological substrate of dystonia. We have tried to define the tone of our review by a couple of Professor John Rothwell's many inspiring characteristics; his endless curiosity to refine knowledge and disease models by scientific exploration and his wise yet humble readiness to revise scientific doctrines when the evidence is supportive. We conclude that high variability of response to non-invasive brain stimulation plasticity protocols significantly clouds the interpretation of historical findings in dystonia research. There is an opportunity to wipe the slate clean of assumptions and armed with an informative literature in health, re-evaluate whether excessive plasticity has a causal role in the pathophysiology of dystonia.

Sex differences in movement disorders

In a range of neurological conditions, including movement disorders, sex-related differences are emerging not only in brain anatomy and function, but also in pathogenesis, clinical features and response to treatment. In Parkinson disease (PD), for example, oestrogens can influence the severity of motor symptoms, whereas elevation of androgens can exacerbate tic disorders. Nevertheless, the real impact of sex differences in movement disorders remains under-recognized. In this article, we provide an up-to-date review of sex-related differences in PD and the most common hyperkinetic movement disorders, namely, essential tremor, dystonia, Huntington disease and other chorea syndromes, and Tourette syndrome and other chronic tic disorders. We highlight the most relevant clinical aspects of movement disorders that differ between men and women. Increased recognition of these differences and their impact on patient care could aid the development of tailored approaches to the management of movement disorders and enable the optimization of preclinical research and clinical studies.