Cognition in myotonic dystrophy type 1: a 5-year follow-up study

Association between Reported Sleep Disorders and Behavioral Issues in Children with Myotonic Dystrophy Type 1-Results from a Retrospective Analysis in Italy

Background: Sleep disorders have been poorly described in congenital (CDM) and childhood (ChDM) myotonic dystrophy despite being highly burdensome. The aims of this study were to explore sleep disorders in a cohort of Italian CDM and ChDM and to assess their association with motor and respiratory function and disease-specific cognitive and behavioral assessments. Methods: This was an observational multicenter study. Reported sleep quality was assessed using the Pediatric Daytime Sleepiness Scale (PDSS) and Pediatric Sleep Questionnaire (PSQ). Sleep quality was correlated to motor function (6 min walk test, 6MWT and grip strength; pulmonary function (predicted Forced Vital Capacity%, FVC% pred.); executive function assessed by BRIEF-2; autism traits assessed by Autism Spectrum Screening Questionnaire (ASSQ) and Repetitive Behavior Scale-revised (RBS-R); Quality of life (PedsQL) and disease burden (Congenital Childhood Myotonic Dystrophy Health Index, CCMDHI). Results: Forty-six patients were included, 33 CDM and 13 ChDM, at a median age of 10.4 and 15.1 years. Daytime sleepiness and disrupted sleep were reported by 30% children, in both subgroups of CDM and ChDM. Daytime sleepiness correlated with autism traits in CDM (p < 0.05). Disrupted sleep correlated with poorer executive function (p = 0.04) and higher disease burden (p = 0.03). Conclusions: Sleep issues are a feature of both CDM and ChDM. They correlate with behavioral issues and impact on disease burden.

Common Characteristics Between Frailty and Myotonic Dystrophy Type 1: A Narrative Review

Myotonic dystrophy type 1 (DM1) is an inherited neuromuscular disorder often considered a model of accelerated aging due to the early appearance of certain age-related clinical manifestations and cellular and molecular aging markers. Frailty, a state of vulnerability related to aging, has been recently studied in neurological conditions but has received considerably less attention in neuromuscular disorders. This narrative review aims to describe 1) the common characteristics between Fried's frailty phenotype criteria (muscular weakness, slow gait speed, weight loss, exhaustion/fatigue, and low physical activity) and DM1, and 2) the psychological and social factors potentially contributing to frailty in DM1. This review gathered evidence suggesting that DM1 patients meet four of the five frailty phenotype criteria. Additionally, longitudinal studies report the deterioration of these criteria over time in DM1. Patients also exhibit psychological/cognitive and social factors that might contribute to frailty. Monitoring frailty criteria in the DM1 population could help to implement timely preventions and interventions to reduce the disease burden and severity of frailty symptoms.

Neurocognitive disorder in Myotonic dystrophy type 1

Cognitive deficits and abnormal cognitive aging have been associated with Myotonic dystrophy type 1 (DM1), but the knowledge of the extent and progression of decline is limited. The aim of this study was to examine the prevalence of signs of neurocognitive disorder (mild cognitive impairment and dementia) in adult patients with DM1. A total of 128 patients with childhood, juvenile, adult, and late onset DM1 underwent a screening using the Montreal Cognitive Assessment (MoCA). Demographic and clinical information was collected. The results revealed that signs of neurocognitive disorder were relatively rare among the participants. However, 23.8 % of patients with late onset DM1 (aged over 60 years) scored below MoCA cut-off (=23), and this group also scored significantly worse compared to patients with adult onset. Age at examination were negatively correlated with MoCA scores, although it only explained a small portion of the variation in test results. Other demographic and clinical factors showed no association with MoCA scores. In conclusion, our findings indicate a low prevalence of signs of neurocognitive disorder in adult patients with DM1, suggesting that cognitive deficits rarely progress to severe disorders over time. However, the performance of patients with late onset DM1 suggests that this phenotype warrants further exploration in future studies, including longitudinal and larger sample analyses.

Myotonic dystrophy type 1 - a multiorgan disorder

Myotonic dystrophy type 1 is an autosomal dominant, inherited multiorgan disorder that can affect people of all ages. It is the most prevalent inherited muscular disease in adults. Late diagnosis points to limited knowledge among the medical community that symptoms other than typical muscular symptoms can dominate. The condition often worsens with each generation and some families are severely affected. Significantly delayed diagnosis means a risk of more serious development of the disorder and inadequate symptomatic treatment. We hope that this clinical review article may lead to more rapid diagnosis and better follow-up of this patient group.

Cognitive impairment, neuroimaging abnormalities, and their correlations in myotonic dystrophy: a comprehensive review

Myotonic dystrophy (DM) encompasses a spectrum of neuromuscular diseases characterized by myotonia, muscle weakness, and wasting. Recent research has led to the recognition of DM as a neurological disorder. Cognitive impairment is a central nervous system condition that has been observed in various forms of DM. Neuroimaging studies have increasingly linked DM to alterations in white matter (WM) integrity and highlighted the relationship between cognitive impairment and abnormalities in WM structure. This review aims to summarize investigations into cognitive impairment and brain abnormalities in individuals with DM and to elucidate the correlation between these factors and the potential underlying mechanisms contributing to these abnormalities.

Transcranial brain parenchyma sonographic findings in patients with myotonic dystrophy type 1 and 2

Introduction

Myotonic dystrophy type 1 (DM1) and 2 (DM2) are genetically determined progressive muscular disorders with multisystemic affection, including brain involvement. Transcranial sonography (TCS) is a reliable diagnostic tool for the investigation of deep brain structures. We sought to evaluate TCS findings in genetically confirmed DM1 and DM2 patients, and further correlate these results with patients' clinical features.

Methods

This cross-sectional study included 163 patients (102 DM1, 61 DM2). Echogenicity of the brainstem raphe (BR) and substantia nigra (SN) as well as the diameter of the third ventricle (DTV) were assessed by TCS. Patients were evaluated using the Hamilton Depression Rating Scale, Fatigue Severity Scale and Daytime Sleepiness Scale.

Results

SN hyperechogenicity was observed in 40% of DM1 and 34% of DM2 patients. SN hypoechogenicity was detected in 17% of DM1 and 7% of DM2 patients. BR hypoechogenicity was found in 36% of DM1 and 47% of DM2 subjects. Enlarged DTV was noted in 19% of DM1 and 15% of DM2 patients. Older, weaker, depressive, and fatigued DM1 patients were more likely to have BR hypoechogenicity (p < 0.05). DTV correlated with age and disease duration in DM1 (p < 0.01). In DM2 patients SN hyperechogenicity correlated with fatigue. Excessive daytime sleepiness was associated with hypoechogenic BR (p < 0.05) and enlarged DVT (p < 0.01) in DM2 patients.

Conclusions

TCS is an easy applicable and sensitive neuroimaging technique that could offer new information regarding several brainstem structures in DM1 and DM2. This may lead to better understanding of the pathogenesis of the brain involvement in DM with possible clinical implications.

Neurobehavioral Phenotype of Children With Congenital Myotonic Dystrophy

BACKGROUND AND OBJECTIVES

To describe the neurobehavioral phenotype of congenital myotonic dystrophy. Congenital myotonic dystrophy (CDM) is the most severe form of myotonic dystrophy, characterized by symptom presentation at birth and later, cognitive impairment, autistic features, and disordered sleep.

METHODS

The neurobehavioral phenotype was assessed in this cross-sectional study by a neuropsychological battery consisting of the Wechsler Preschool and Primary Scale of Intelligence, Third Edition, Weschler Intelligence Scale for Children, Fourth Edition, Vineland Adaptive Behavior Scale, Second Edition (Vineland-II), Behavior Rating Inventory of Executive Function including preschool and teacher reports, Autism Spectrum Screening Questionnaire, Social Communication Scale, and Repetitive Behavior Scale-Revised. Sleep quality was evaluated with the Pediatric Sleep Questionnaire and Pediatric Daytime Sleepiness Scale.

RESULTS

Fifty-five children with CDM, ages 5 weeks to 14 years, were enrolled. The mean age and (CTG)n repeats (±SD) were 6.4 ± 3.8 years and 1,263 ± 432, respectively. The mean IQ was 64.1 ± 14.9 on the Weschler scales with 65.6% of participants falling in the extremely low range for IQ. Adaptive functioning was significantly low for 57.1% of participants (n = 20). Caregiver report of executive functioning indicated 23.1% (9/39) of participants had clinically elevated levels of dysfunction, though teacher report was discrepant and indicated 53.3% of participants with CDM fell in this range (8/15). Spearman correlations were strongly positive (p ≤ 0.05) for estimated full scale IQ, overall adaptive functioning and with daily living and socialization domain standard scores on the Vineland-II ranging from r = 0.719 to r = 0.849 for all ages. Aspects of executive function were directly related to features of autism and sleep quality. Social communication was inversely related to all aspects of daily functioning, except communication, and directly related to aspects of autism behavior.

DISCUSSION

Depressed IQ, adaptive skills, and executive functioning, poor sleep quality, and features of autism and altered social functioning individually describe different aspects of the neurobehavioral phenotype in CDM. These neurobehavioral and sleep measures could help quantitatively measure and assess the burden of cognitive impairment in CDM.

Longitudinal changes in white matter as measured with diffusion tensor imaging in adult-onset myotonic dystrophy type 1

Myotonic dystrophy type 1 is characterized by neuromuscular degeneration. Our objective was to compare change in white matter microstructure (fractional anisotropy, radial and axial diffusivity), and functional/clinical measures. Participants underwent yearly neuroimaging and neurocognitive assessments over three-years. Assessments encompassed full-scale intelligence, memory, language, visuospatial skills, attention, processing speed, and executive function, as well as clinical symptoms of muscle/motor function, apathy, and hypersomnolence. Mixed effects models were used to examine differences. 69 healthy adults (66.2% women) and 41 DM1 patients (70.7% women) provided 156 and 90 observations, respectively. There was a group by elapsed time interaction for cerebral white matter, where DM1 patients exhibited declines in white matter (all p<0.05). Likewise, DM1 patients either declined (motor), improved more slowly (intelligence), or remained stable (executive function) for functional outcomes. White matter was associated with functional performance; intelligence was predicted by axial (r = 0.832; p<0.01) and radial diffusivity (r = 0.291, p<0.05), and executive function was associated with anisotropy (r = 0.416, p<0.001), and diffusivity (axial: r = 0.237, p = 0.05 and radial: r = 0.300, p<0.05). Indices of white matter health are sensitive to progression in DM1. These results are important for clinical trial design, which utilize short intervals to establish treatment efficacy.

267th ENMC International workshop: psychological interventions for improving quality of life in slowly progressive neuromuscular disorders

This workshop aimed to develop recommendations for psychological interventions to support people living with slowly progressive neuromuscular disorders (NMD). The workshop comprised clinicians, researchers, people living with NMD and their relatives. First, participants considered the key psychological challenges presented by NMD and the impact of NMD on relationships and mental health. Later, several psychological approaches for enhancing well-being in NMD were described. The results of randomised controlled trials of Cognitive Behaviour Therapy and Acceptance and Commitment Therapy for improving fatigue, quality of life, and mood in adults with NMD were examined. Then the group considered ways to adapt therapies for cognitive impairments or neurodevelopmental differences that occur in some NMD, alongside ways to support children and adolescents with NMD and their family members. Based on the evidence from randomised controlled trials, carefully conducted observational studies, and the coherence of these data with the experience of those living with NMD, the group recommends that psychological interventions should be embedded in the routine clinical care offered to people living with NMD.

Do classical and computerized cognitive tests have equal intrarater reliability in myotonic dystrophy type 1?

Myotonic dystrophy type 1 (DM1) is a multisystemic inherited neuromuscular disease leading to central nervous system symptoms, including cognitive impairments, among multiple other symptoms. However, information is presently lacking regarding the psychometric properties of neuropsychological tests and promising computerized cognitive tests, such as the Cambridge Neuropsychological Test Automated Battery (CANTAB^Ⓡ). This type of information is critical to improve clinical trial readiness and provide knowledge of DM1 natural history. The aims of the present study were (1) to document the intrarater reliability of classic paper-pencil tests assessing visuospatial working memory, cognitive flexibility, attention, episodic memory and apathy, and (2) to compare these findings with their equivalent computerized automated tests from the CANTAB^Ⓡ. Thirty participants were seen twice at four-week intervals. Results showed that the Stroop Color and Word Test (ICC = 0.741-0.869) and the Ruff 2 & 7 (ICC = 0.703-0.871) appear to be reliable paper-and-pencil tests in the DM1 population. For the CANTAB^Ⓡ, a similar observation was made for the Multitasking test (ICC = 0.588-0.792). Further studies should explore the applicability and concurrent validity of the CANTAB® and classic neuropsychological assessments in additional cohorts of DM1 patients.

Shedding light on motor premanifest myotonic dystrophy type 1: A molecular, muscular and central nervous system follow-up study

BACKGROUND AND PURPOSE

Myotonic dystrophy type 1 (DM1) is a hereditary and multisystemic disease that is characterized by heterogeneous manifestations. Although muscular impairment is central to DM1, a premanifest DM1 form has been proposed for those characterized by the absence of muscle signs in precursory phases. Nevertheless, subtle signs and/or symptoms related to other systems, such as the central nervous system (CNS), may emerge and progress gradually. This study aimed to validate the premanifest DM1 concept and to characterize and track affected individuals from a CNS centred perspective.

METHODS

Retrospective data of 120 participants (23 premanifest DM1, 25 manifest DM1 and 72 healthy controls) were analysed transversally and longitudinally (over 11.17 years). Compiled data included clinical, neuropsychological and neuroradiological (brain volume and white matter lesion, WML) measures taken at two time points.

RESULTS

Manifest DM1 showed significantly more molecular affectation, worse performance on neuropsychological domains, lower grey and white matter volumes and a different pattern of WMLs than premanifest DM1. The latter was slightly different from healthy controls regarding brain volume and WMLs. Additionally, daytime sleepiness and molecular expansion size explained 50% of the variance of the muscular deterioration at follow-up in premanifest individuals.

CONCLUSIONS

Premanifest DM1 individuals showed subtle neuroradiological alterations, which suggests CNS involvement early in the disease. Based on follow-up data, a debate emerges around the existence of a 'non-muscular DM1' subtype and/or a premanifest phase, as a precursory stage to other DM1 manifestations.

Longitudinal Changes in Neuropsychological Functioning in Japanese Patients with Myotonic Dystrophy Type 1: A Five Year Follow-Up Study

BACKGROUND

Myotonic dystrophy type 1 (DM1) is a form of muscular dystrophy that causes various symptoms, including those of the central nervous system. Some studies have reported cognitive decline in patients with DM1, although the available evidence is limited.

OBJECTIVE

This study aimed to describe longitudinal differences in neuropsychological function in patients with DM1.

METHODS

A total of 66 Japanese adult patients with DM1 were investigated using a neuropsychological battery to assess several cognitive domains, including memory, processing speed, and executive function. The patients underwent neuropsychological evaluation approximately five years after baseline (Times 1 and 2).

RESULTS

Thirty-eight patients underwent a second neuropsychological evaluation. The participants in the Time 2 evaluation were younger than those who did not participate in Time 2. Patients showed a decline in the Mini-Mental State Examination, Trail Making Test (TMT), Block Design, and Symbol Digit Modalities Test at Time 2 (P < 0.05). Age at Time 1 was associated with a decline in TMT-A and TMT-B scores (rho = 0.57 and 0.45, respectively).

CONCLUSION

These results suggest a cognitive decline in patients with DM1 and warrant further investigation into the possible effects of age-related changes.

Gray Matter Abnormalities in Myotonic Dystrophy Type 1: A Voxel-Wise Meta-Analysis

Background

A growing number of voxel-based morphometry (VBM) studies have demonstrated widespread gray matter (GM) abnormalities in myotonic dystrophy type 1 (DM1), but the findings are heterogeneous. This study integrated previous VBM studies to identify consistent GM changes in the brains of patients with DM1.

Methods

Systematic retrieval was conducted in Web of Science, Pubmed, and Embase databases to identify VBM studies that met the inclusion requirements. Data were extracted. The Seed-based d Mapping with Permutation of Subject Images (SDM-PSI) software was used for meta-analysis of voxel aspects.

Results

A total of eight VBM studies were included, including 176 patients with DM1 and 198 healthy controls (HCs). GM volume in patients with DM1 was extensively reduced compared with HCs, including bilateral rolandic operculum, bilateral posterior central gyrus, bilateral precentral gyrus, right insula, right heschl gyrus, right superior temporal gyrus, bilateral supplementary motor area, bilateral middle cingulate gyrus/paracingulate gyrus, left paracentral lobule, and bilateral caudate nucleus. Meta-regression analysis found that regional GM abnormalities were associated with disease duration and Rey-Osterrieth Complex Figure (ROCF)-recall scores.

Conclusion

DM1 is not only a disease of muscle injury but also a multisystem disease involving brain motor and neuropsychiatric regions, providing a basis for the pathophysiological mechanism of DM1.

Cognitive, neuropsychological and emotional-behavioural functioning in a sample of children with myotonic dystrophy type 1

AIM

An observational longitudinal study to evaluate the feasibility of assessing cognitive, neuropsychological and emotional-behavioural functioning in children with myotonic dystrophy type 1 (DM1), and to estimate prospectively changes in functioning over time.

METHOD

Ten DM1 patients, aged 1.5-16 years (mean 9.1), 5 with congenital DM1, and 5 with childhood DM1, were assessed with standardized measures of intellectual, neuropsychological, and emotional-behavioural functioning. For 6 patients, assessments were repeated 2 years later.

RESULTS

At baseline, intellectual disability was found both in the congenital and the childhood group. A clear-cut reduction of the mean and individual developmental/intelligence quotient after 2 years was demonstrated in re-tested patients. As regards to the neuropsychological aspects, the baseline evaluation identified impairments in visuospatial skills and attentional functions, with no clear trend observed after two years. In executive functions, no significant profile was identified even though impairments were detected in a few patients. At the emotional-behavioural assessment, scores in clinical range were found, but they remained heterogeneous and no trends could be recognized.

CONCLUSION

Several aspects of CNS functions in DM1 children deserve better definition and a longitudinal assessment. A comprehensive protocol should include cognitive, neuropsychological, emotional and behavioural assessment but larger longitudinal studies are needed to better evaluate the trajectories over time and inform practice.

Tau positron emission tomography, cerebrospinal fluid and plasma biomarkers of neurodegeneration, and neurocognitive testing: an exploratory study of participants with myotonic dystrophy type 1

OBJECTIVE

To investigate Tau pathology using multimodal biomarkers of neurodegeneration and neurocognition in participants with myotonic dystrophy type 1 (DM1).

METHODS

We recruited twelve participants with DM1 and, for comparison, two participants with Alzheimer's Disease (AD). Participants underwent cognitive screening and social cognition testing using the Dépistage Cognitif de Québec (DCQ), among other tests. Biomarkers included Tau PET with [18F]-AV-1451, CSF (Aβ, Tau, phospho-Tau), and plasma (Aβ, Tau, Nf-L, GFAP) studies.

RESULTS

Of the twelve DM1 participants, seven completed the full protocol (Neurocognition 11/12; PET 7/12, CSF 9/12, plasma 12/12). Three DM1 participants were cognitively impaired (CI). On average, CI DM1 participants had lower scores on the DCQ compared to cognitively unimpaired (CU) DM1 participants (75.5/100 vs. 91.4/100) and were older (54 vs. 44 years old) but did not differ in years of education (11.3 vs. 11.1). The majority (6/7) of DM1 participants had no appreciable PET signal. Only one of the CI participants presented with elevated Tau PET SUVR in bilateral medial temporal lobes. This participant was the eldest and most cognitively impaired, and had the lowest CSF Aβ 1-42 and the highest CSF Tau levels, all suggestive of co-existing AD. CSF Tau and phospho-Tau levels were higher in the 3 CI compared to CU DM1 participants, but with a mean value lower than that typically observed in AD. Nf-L and GFAP were elevated in most DM1 participants (9/11 and 8/11, respectively). Finally, CSF phospho-Tau was significantly correlated with plasma Nf-L concentrations.

CONCLUSIONS AND RELEVANCE

We observed heterogenous cognitive and biomarker profiles in individuals with DM1. While some participants presented with abnormal PET and/or CSF Tau, these patterns were highly variable and only present in a small subset. Although DM1 may indeed represent a non-AD Tauopathy, the Tau-PET tracer used in this study was unable to detect an in vivo Tau DM1 signature in this small cohort. Interestingly, most DM1 participants presented with elevated plasma Nf-L and GFAP levels, suggestive of other, possibly related, central brain alterations which motivate further research. This pioneering study provides novel insights towards the potential relationship between biomarkers and neurocognitive deficits commonly seen in DM1.

Explanatory factors of dynamic balance impairment in myotonic dystrophy type 1

INTRODUCTION/AIMS

Myotonic dystrophy type 1 (DM1) is a neuromuscular disease affecting many systems and for which muscle weakness is one of the cardinal symptoms. People with DM1 also present with balance-related impairments and high fall risk. The aim of this study was to explore explanatory factors of dynamic balance impairment in the DM1 population.

METHODS

A secondary analysis of data collected as part of a larger study was performed. The Mini Balance Evaluation System Test (Mini-BESTest) was used to assess dynamic balance. Age, sex, and CTG repeat length in blood were retrieved from medical records and research files. The maximal isometric muscle strength of five lower limb muscle groups (hip flexors and extensors, knee flexors and extensors, and ankle dorsiflexors) was quantitatively assessed as well as fatigue. Standard multiple regression analysis was used.

RESULTS

Fifty-two individuals (31 men) aged between 24 and 81 years were included. The final model explains 65.9% of the balance score; ankle dorsiflexor muscle strength was the strongest explanatory factor, followed by CTG repeat length, age and fatigue to a lesser extent.

DISCUSSION

Dynamic balance is impaired in people with DM1. Results of this study suggest that rehabilitation interventions aimed at improving strength of the ankle dorsiflexors and managing fatigue could help to improve dynamic balance in this specific population.

Unravelling the impact of frontal lobe impairment for social dysfunction in myotonic dystrophy type 1

Myotonic dystrophy type 1 is an autosomal dominant multisystemic disorder affecting muscular and extra muscular systems, including the central nervous system. Cerebral involvement in myotonic dystrophy type 1 is associated with subtle cognitive and behavioural disorders, of major impact on socio-professional adaptation. The social dysfunction and its potential relation to frontal lobe neuropsychology remain under-evaluated in this pathology. The neuroanatomical network underpinning that disorder is yet to disentangle. Twenty-eight myotonic dystrophy type 1 adult patients (mean age: 46 years old) and 18 age and sex-matched healthy controls were included in the study. All patients performed an exhaustive neuropsychological assessment with a specific focus on frontal lobe neuropsychology (motivation, social cognition and executive functions). Among them, 18 myotonic dystrophy type 1 patients and 18 healthy controls had a brain MRI with T1 and T2 Flair sequences. Grey matter segmentation, Voxel-based morphometry and cortical thickness estimation were performed with Statistical Parametric Mapping Software SPM12 and Freesurfer software. Furthermore, T2 white matter lesions and subcortical structures were segmented with Automated Volumetry Software. Most patients showed significant impairment in executive frontal functions (auditory working memory, inhibition, contextualization and mental flexibility). Patients showed only minor difficulties in social cognition tests mostly in cognitive Theory of Mind, but with relative sparing of affective Theory of Mind and emotion recognition. Neuroimaging analysis revealed atrophy mostly in the parahippocampal and hippocampal regions and to a lesser extent in basal ganglia, regions involved in social navigation and mental flexibility, respectively. Social cognition scores were correlated with right parahippocampal gyrus atrophy. Social dysfunction in myotonic dystrophy type 1 might be a consequence of cognitive impairment regarding mental flexibility and social contextualization rather than a specific social cognition deficit such as emotion recognition. We suggest that both white matter lesions and grey matter disease could account for this social dysfunction, involving, in particular, the frontal-subcortical network and the hippocampal/arahippocampal regions, brain regions known, respectively, to integrate contextualization and social navigation.

Cellular Senescence and Aging in Myotonic Dystrophy

Myotonic dystrophy (DM) is a dominantly inherited multisystemic disorder affecting various organs, such as skeletal muscle, heart, the nervous system, and the eye. Myotonic dystrophy type 1 (DM1) and type 2 (DM2) are caused by expanded CTG and CCTG repeats, respectively. In both forms, the mutant transcripts containing expanded repeats aggregate as nuclear foci and sequester several RNA-binding proteins, resulting in alternative splicing dysregulation. Although certain alternative splicing events are linked to the clinical DM phenotypes, the molecular mechanisms underlying multiple DM symptoms remain unclear. Interestingly, multi-systemic DM manifestations, including muscle weakness, cognitive impairment, cataract, and frontal baldness, resemble premature aging. Furthermore, cellular senescence, a critical contributor to aging, is suggested to play a key role in DM cellular pathophysiology. In particular, several senescence inducers including telomere shortening, mitochondrial dysfunction, and oxidative stress and senescence biomarkers such as cell cycle inhibitors, senescence-associated secretory phenotype, chromatin reorganization, and microRNA have been implicated in DM pathogenesis. In this review, we focus on the clinical similarities between DM and aging, and summarize the involvement of cellular senescence in DM and the potential application of anti-aging DM therapies.

Brief assessment of cognitive function in myotonic dystrophy: multicenter longitudinal study using computer-assisted evaluation

INTRODUCTION/AIMS

Myotonic dystrophy type 1 (DM1) is known to affect cognitive function, but the best methods to assess CNS involvement in multicenter studies have not been determined. This study's primary aim was to evaluate the potential of computerized cognitive tests to assess cognition in DM1.

METHODS

We conducted a prospective, longitudinal, observational study of 113 adults with DM1 at 6 sites. Psychomotor speed, attention, working memory, and executive functioning were assessed at baseline, 3-months and 12-months using computerized cognitive tests. Results were compared with assessments of muscle function and patient reported outcomes (PROs), including the Myotonic Dystrophy Health Index (MDHI) and EQ-5D-5L.

RESULTS

Based on intra-class correlation coefficients (ICCs), computerized cognitive tests had moderate to good reliability for psychomotor speed (0.76), attention (0.82), working memory speed (0.79), working memory accuracy (0.65), and executive functioning (0.87). Performance at baseline was lowest for working memory accuracy (p < 0.0001). Executive function performance improved from baseline to 3-months (p < 0.0001), without further changes over one year. There was a moderate correlation between poorer executive function and larger CTG repeat size (r = -0.433). There were some weak associations between PROs and cognitive performance.

DISCUSSION

Computerized tests of cognition are feasible in multicenter studies of DM1. Poor performance was exhibited in working memory, which may be a useful variable in clinical trials. Learning effects may have contributed to the improvement in executive functioning. The relationship between PROs and cognitive impairment in DM1 requires further study. This article is protected by copyright. All rights reserved.

Brain Pathogenesis and Potential Therapeutic Strategies in Myotonic Dystrophy Type 1

Myotonic dystrophy type 1 (DM1) is the most common muscular dystrophy that affects multiple systems including the muscle and heart. The mutant CTG expansion at the 3'-UTR of the DMPK gene causes the expression of toxic RNA that aggregate as nuclear foci. The foci then interfere with RNA-binding proteins, affecting hundreds of mis-spliced effector genes, leading to aberrant alternative splicing and loss of effector gene product functions, ultimately resulting in systemic disorders. In recent years, increasing clinical, imaging, and pathological evidence have indicated that DM1, though to a lesser extent, could also be recognized as true brain diseases, with more and more researchers dedicating to develop novel therapeutic tools dealing with it. In this review, we summarize the current advances in the pathogenesis and pathology of central nervous system (CNS) deficits in DM1, intervention measures currently being investigated are also highlighted, aiming to promote novel and cutting-edge therapeutic investigations.

Deciphering the mechanisms underlying brain alterations and cognitive impairment in congenital myotonic dystrophy

Myotonic dystrophy type 1 (DM1) is a multisystemic and heterogeneous disorder caused by the expansion of CTG repeats in the 3' UTR of the myotonic dystrophy protein kinase (DMPK) gene. There is a congenital form (CDM1) of the disease characterized by severe hypotonia, respiratory insufficiency as well as developmental delays and intellectual disabilities. CDM1 infants manifest important brain structure abnormalities present from birth while, in contrast, older patients with adult-onset DM1 often present neurodegenerative features and milder progressive cognitive deficits. Promising therapies targeting central molecular mechanisms contributing to the symptoms of adult-onset DM1 are currently in development, but their relevance for treating cognitive impairment in CDM1, which seems to be a partially distinct neurodevelopmental disorder, remain to be elucidated. Here, we provide an update on the clinical presentation of CDM1 and review recent in vitro and in vivo models that have provided meaningful insights on its consequences in development, with a particular focus on the brain. We discuss how enhanced toxic gain-of-function of the mutated DMPK transcripts with larger CUG repeats and the resulting dysregulation of RNA-binding proteins may affect the developing cortex in utero. Because the methylation of CpG islets flanking the trinucleotide repeats has emerged as a strong biomarker of CDM1, we highlight the need to investigate the tissue-specific impacts of these chromatin modifications in the brain. Finally, we outline promising potential therapeutic treatments for CDM1 and propose future in vitro and in vivo models with great potential to shed light on this disease.

Cognitive Deficits, Apathy, and Hypersomnolence Represent the Core Brain Symptoms of Adult-Onset Myotonic Dystrophy Type 1

Myotonic dystrophy type 1 is the most common form of muscular dystrophy in adults, and is primarily characterized by muscle weakness and myotonia, yet some of the most disabling symptoms of the disease are cognitive and behavioral. Here we evaluated several of these non-motor symptoms from a cross-sectional time-point in one of the largest longitudinal studies to date, including full-scale intelligence quotient, depression, anxiety, apathy, sleep, and cerebral white matter fractional anisotropy in a group of 39 adult-onset myotonic dystrophy type 1 participants (27 female) compared to 79 unaffected control participants (46 female). We show that intelligence quotient was significantly associated with depression (P < 0.0001) and anxiety (P = 0.018), but not apathy (P < 0.058) or hypersomnolence (P = 0.266) in the DM1 group. When controlling for intelligence quotient, cerebral white matter fractional anisotropy was significantly associated with apathy (P = 0.042) and hypersomnolence (P = 0.034), but not depression (P = 0.679) or anxiety (P = 0.731) in the myotonic dystrophy type 1 group. Finally, we found that disease duration was significantly associated with apathy (P < 0.0001), hypersomnolence (P < 0.001), IQ (P = 0.038), and cerebral white matter fractional anisotropy (P < 0.001), but not depression (P = 0.271) or anxiety (P = 0.508). Our results support the hypothesis that cognitive deficits, hypersomnolence, and apathy, are due to the underlying neuropathology of myotonic dystrophy type 1, as measured by cerebral white matter fractional anisotropy and disease duration. Whereas elevated symptoms of depression and anxiety in myotonic dystrophy type 1 are secondary to the physical symptoms and the emotional stress of coping with a chronic and debilitating disease. Results from this work contribute to a better understanding of disease neuropathology and represent important therapeutic targets for clinical trials.

New developments in myotonic dystrophies from a multisystemic perspective

PURPOSE OF REVIEW

The multisystemic involvement of myotonic dystrophies (DMs) intricates disease monitoring, patients' care and trial design. This update of the multifaceted comorbidities observed in DMs aims to assist neurologists in the complex management of patients and to encourage further studies for still under-investigated aspects of the disease.

RECENT FINDINGS

We reviewed the most recent studies covering pathogenesis and clinical aspects of extra-muscular involvement in DM1 and DM2. The largest body of evidence regards the cardiac and respiratory features, for which experts' recommendations have been produced. Gastrointestinal symptoms emerge as one of the most prevalent complaints in DMs. The alteration of insulin signaling pathways, involved in gastrointestinal manifestations, carcinogenesis, muscle function, cognitive and endocrinological aspects, gain further relevance in the light of recent evidence of metformin efficacy in DM1. Still, too few studies are performed on large DM2 cohorts, so that current recommendations mainly rely on data gathered in DM1 that cannot be fully translated to DM2.

SUMMARY

Extra-muscular manifestations greatly contribute to the overall disease burden. A multidisciplinary approach is the key for the management of patients. Consensus-based recommendations for DM1 and DM2 allow high standards of care but further evidence are needed to implement these recommendations.

DNA methylation at the DMPK gene locus is associated with cognitive functions in myotonic dystrophy type 1

Aim: Myotonic dystrophy type 1 (DM1) is caused by an unstable trinucleotide (CTG) expansion at the DMPK gene locus. Cognitive dysfunctions are often observed in the condition. We investigated the association between DMPK blood DNA methylation (DNAm) and cognitive functions in DM1, considering expansion length and variant repeats (VRs). Method: Data were obtained from 115 adult-onset DM1 patients. Molecular analyses consisted of pyrosequencing, small pool PCR and Southern blot hybridization. Cognitive functions were assessed by validated neuropsychological tests. Results: For patients without VRs (n = 103), blood DNAm at baseline independently contributed to predict cognitive functions 9 years later. Patients with VRs (n = 12) had different DNAm and cognitive profiles. Conclusion: DNAm allows to better understand DM1-related cognitive dysfunction etiology.

Longitudinal study in patients with myotonic dystrophy type 1: correlation of brain MRI abnormalities with cognitive performances

PURPOSE

Myotonic dystrophy type 1 (DM1) is a muscular dystrophy with neurological, cognitive, and radiological abnormalities. The developmental or degenerative nature of these abnormalities, and their progression over time, remains unclear. The aim of this study is to perform a longitudinal assessment of imaging and cognitive performances in a group of patients with DM1.

METHODS

A longitudinal observational study was conducted in a group of 33 DM1 patients. All patients underwent cognitive and MRI evaluation, including the use of structural and diffusion tensor imaging techniques, at baseline and follow-up evaluation (4 years). Longitudinal changes in white matter lesion (WML), volumetric analysis, and diffusivity values were assessed and correlated with neuropsychological test findings.

RESULTS

An increase in WML was observed in 16 patients (48.5%). An increase in ventricular system volume and a decrease in volume of the left thalamus, caudates, putamen, and hippocampus were observed (p < 0.001). Global cortical volume showed a significant decrease (p < 0.001), although no changes were observed in white matter volume. A significant increase in mean diffusivity and decrease in fractional anisotropy for the white matter were found (p < 0.001). Neuropsychological evaluation showed a significant deterioration in test performance that measures working memory (Letter-Number Sequencing, p = 0.049) and visuospatial skills (Benton Visual Retention Test, p = 0.001). These findings were significantly associated with WML load (working memory p = 0.002 and visuospatial skills p = 0.021) and mean diffusivity increase (visuospatial skills p = 0.003 in the corpus callosum and working memory p = 0.043 in the right cerebral white matter).

CONCLUSION

White matter and grey matter involvement in DM1 patients is progressive. Patients experience a worsening in cognitive impairment that correlates with white matter involvement. These findings support the neurodegenerative nature of this disease.

Central Nervous System Involvement as Outcome Measure for Clinical Trials Efficacy in Myotonic Dystrophy Type 1

Increasing evidences indicate that in Myotonic Dystrophy type 1 (DM1 or Steinert disease), an autosomal dominant multisystem disorder caused by a (CTG)n expansion in DMPK gene on chromosome 19q13. 3, is the most common form of inherited muscular dystrophy in adult patients with a global prevalence of 1/8000, and involvement of the central nervous system can be included within the core clinical manifestations of the disease. Variable in its severity and progression rate over time, likely due to the underlying causative molecular mechanisms; this component of the clinical picture presents with high heterogeneity involving cognitive and behavioral alterations, but also sensory-motor neural integration, and in any case, significantly contributing to the disease burden projected to either specific functional neuropsychological domains or quality of life as a whole. Principle manifestations include alterations of the frontal lobe function, which is more prominent in patients with an early onset, such as in congenital and childhood onset forms, here associated with severe intellectual disabilities, speech and language delay and reduced IQ-values, while in adult onset DM1 cognitive and neuropsychological findings are usually not so severe. Different methods to assess central nervous system involvement in DM1 have then recently been developed, these ranging from more classical psychometric and cognitive functional instruments to sophisticated psycophysic, neurophysiologic and especially computerized neuroimaging techniques, in order to better characterize this disease component, at the same time underlining the opportunity to consider it a suitable marker on which measuring putative effectiveness of therapeutic interventions. This is the reason why, as outlined in the conclusive section of this review, the Authors are lead to wonder, perhaps in a provocative and even paradoxical way to arise the question, whether or not the myologist, by now the popular figure in charge to care of a patient with the DM1, needs to remain himself a neurologist to better appreciate, evaluate and speculate on this important aspect of Steinert disease.

Neurodegeneration trajectory in pediatric and adult/late DM1: A follow-up MRI study across a decade

OBJECTIVE

To characterize the progression of brain structural abnormalities in adults with pediatric and adult/late onset DM1, as well as to examine the potential predictive markers of such progression.

METHODS

21 DM1 patients (pediatric onset: N = 9; adult/late onset: N = 12) and 18 healthy controls (HC) were assessed longitudinally over 9.17 years through brain MRI. Additionally, patients underwent neuropsychological, genetic, and muscular impairment assessment. Inter-group comparisons of total and voxel-level regional brain volume were conducted through Voxel Based Morphometry (VBM); cross-sectionally and longitudinally, analyzing the associations between brain changes and demographic, clinical, and cognitive outcomes.

RESULTS

The percentage of GM loss did not significantly differ in any of the groups compared with HC and when assessed independently, adult/late DM1 patients and their HC group suffered a significant loss in WM volume. Regional VBM analyses revealed subcortical GM damage in both DM1 groups, evolving to frontal regions in the pediatric onset patients. Muscular impairment and the outcomes of certain neuropsychological tests were significantly associated with follow-up GM damage, while visuoconstruction, attention, and executive function tests showed sensitivity to WM degeneration over time.

INTERPRETATION

Distinct patterns of brain atrophy and its progression over time in pediatric and adult/late onset DM1 patients are suggested. Results indicate a possible neurodevelopmental origin of the brain abnormalities in DM1, along with the possible existence of an additional neurodegenerative process. Fronto-subcortical networks appear to be involved in the disease progression at young adulthood in pediatric onset DM1 patients. The involvement of a multimodal integration network in DM1 is discussed.

Methylphenidate Attenuates the Cognitive and Mood Alterations Observed in Mbnl2 Knockout Mice and Reduces Microglia Overexpression

Myotonic dystrophy type 1 (DM1) is a multisystem disorder affecting muscle and central nervous system (CNS) function. The cellular mechanisms underlying CNS alterations are poorly understood and no useful treatments exist for the neuropsychological deficits observed in DM1 patients. We investigated the progression of behavioral deficits present in male and female muscleblind-like 2 (Mbnl2) knockout (KO) mice, a rodent model of CNS alterations in DM1, and determined the biochemical and electrophysiological correlates in medial prefrontal cortex (mPFC), striatum and hippocampus (HPC). Male KO exhibited more cognitive impairment and depressive-like behavior than female KO mice. In the mPFC, KO mice showed an overexpression of proinflammatory microglia, increased transcriptional levels of Dat, Drd1, and Drd2, exacerbated dopamine levels, and abnormal neural spiking and oscillatory activities in the mPFC and HPC. Chronic treatment with methylphenidate (MPH) (1 and 3 mg/kg) reversed the behavioral deficits, reduced proinflammatory microglia in the mPFC, normalized prefrontal Dat and Drd2 gene expression, and increased Bdnf and Nrf2 mRNA levels. These findings unravel the mechanisms underlying the beneficial effects of MPH on cognitive deficits and depressive-like behaviors observed in Mbnl2 KO mice, and suggest that MPH could be a potential candidate to treat the CNS deficiencies in DM1 patients.

Dyslexia and cognitive impairment in adult patients with myotonic dystrophy type 1: a clinical prospective analysis

BACKGROUND

Cognitive impairments in patients with myotonic dystrophy type 1 (DM1) have often been described, however, there are only few studies differentiating between partial performance disorders and mental retardation in common. This study focused on the evaluation of reading performance and the frequency of dyslexia in adult DM1 patients.

METHODS

We performed a prospective cohort study including genetically confirmed adult DM1 patients registered in the DM registry of Germany or the internal database of the Friedrich-Baur-Institute, Munich, Germany. For the assessment of the patients' reading and spelling performance, we used the standardized and validated test 'Salzburger Lese- und Rechtschreibtest' (SLRT II). The 'CFT-20 R Grundintelligenztest Skala 2' in revised ("R") version (CFT 20-R), determining the intelligence level, was appropriate to differentiate between dyslexia and general mental retardation. The diagnosis of dyslexia, the combined reading and spelling disorder, was based on the guidelines for diagnosis and therapy of children and adolescents with dyslexia 2015 (S3-guideline) providing (1) the criterion of the divergence from age level and (2) the criterion of IQ-divergence.

RESULTS

Fifty-seven DM1 patients participated in our study. Evaluating the reading performance, 16 patients fulfilled the divergence criteria of the age level and 2 patients the IQ-divergence criteria. In total, the diagnosis of a reading disorder was given in 18 DM1 patients (31.6 %). In 11 out of these 18 patients with a reading disorder, a relevant impairment of spelling performance was observed with at least three spelling errors. As there are no normative values for adults in spelling performance, we assume a combined reading disorder and dyslexia, in those 11 DM1 patients (19.3 %). Regarding the separate analyses of the test procedures, in the SLRT II the performance was below average in 40.4 % of all patients for 'word reading' and in 61.4 % of all patients for 'pseudoword reading'. There was a significant positive correlation between the CTG expansion size and a reading disorder (p=0.027). The average IQ of 17 examined DM1 patients was in the lower normal range (86.1 ± 19.1). 54.5 % of patients with reading disorder had a normal IQ.

CONCLUSION

The calculated prevalence of dyslexia in the DM1 study cohort was 19.3 % and thus considerably increased compared to the normal German population. As dyslexia is not equivalent to a general cognitive impairment, it is important not to miss dyslexic features in cognitive inconspicuous DM1 patients. Case-by-case one should consider a differential diagnostic approach, as individualized therapies can be offered to support dyslexic patients in their performance.

Diagnosis of Myotonic Dystrophy Based on Resting State fMRI Using Convolutional Neural Networks

Myotonic dystrophies (DM) are neuromuscular conditions that cause widespread effects throughout the body. There are brain white matter changes on MRI in patients with DM that correlate with neuropsychological functional changes. How these brain alterations causally relate to the presence and severity of cognitive symptoms remains largely unknown. Deep neural networks have significantly improved the performance of image classification of huge datasets. However, its application in brain imaging is limited and not well described, due to the scarcity of labeled training data. In this work, we propose an approach for the diagnosis of DM based on a spatio-temporal deep learning paradigm. The obtained accuracy (73.71%) and sensitivities and specificities showed that the implemented approach based on 4-D convolutional neural networks leads to a compact, discriminative, and fast computing DM-based clinical medical decision support system.Clinical relevance- Many adults with DM experience cognitive and neurological effects impacting their quality of life, and ability to maintain employment. A robust and reliable DM-based clinical decision support system may help reduce the long diagnostic delay common to DM. Furthermore, it can help neurologists better understand the pathophysiology of the disease and analyze effects of new drugs that aim to address the neurological symptoms of DM.

Protective effects of mirtazapine in mice lacking the Mbnl2 gene in forebrain glutamatergic neurons: Relevance for myotonic dystrophy 1

Myotonic dystrophy type 1 (DM1) is a multisystemic disorder characterized by muscle weakness and wasting and by important central nervous system-related symptoms including impairments in executive functions, spatial abilities and increased anxiety and depression. The Mbnl2 gene has been implicated in several phenotypes consistent with DM1 neuropathology. In this study, we developed a tissue-specific knockout mouse model lacking the Mbnl2 gene in forebrain glutamatergic neurons to examine its specific contribution to the neurobiological perturbations related to DM1. We found that these mice exhibit long-term cognitive deficits and a depressive-like state associated with neuronal loss, increased microglia and decreased neurogenesis, specifically in the dentate gyrus (DG). Chronic treatment with the atypical antidepressant mirtazapine (3 and 10 mg/kg) for 21 days rescued these behavioral alterations, reduced inflammatory microglial overexpression, and reversed neuronal loss in the DG. We also show that mirtazapine re-established 5-HT_1A and histaminergic H₁ receptor gene expression in the hippocampus. Finally, metabolomics studies indicated that mirtazapine increased serotonin, noradrenaline, gamma-aminobutyric acid and adenosine production. These data suggest that loss of Mbnl2 gene in the glutamatergic neurons of hippocampus and cortex may underlie the most relevant DM1 neurobiological and behavioral features, and provide evidence that mirtazapine could be a novel potential candidate to alleviate these debilitating symptoms in DM1 patients.

Oxidative Stress in DNA Repeat Expansion Disorders: A Focus on NRF2 Signaling Involvement

DNA repeat expansion disorders are a group of neuromuscular and neurodegenerative diseases that arise from the inheritance of long tracts of nucleotide repetitions, located in the regulatory region, introns, or inside the coding sequence of a gene. Although loss of protein expression and/or the gain of function of its transcribed mRNA or translated product represent the major pathogenic effect of these pathologies, mitochondrial dysfunction and imbalance in redox homeostasis are reported as common features in these disorders, deeply affecting their severity and progression. In this review, we examine the role that the redox imbalance plays in the pathological mechanisms of DNA expansion disorders and the recent advances on antioxidant treatments, particularly focusing on the expression and the activity of the transcription factor NRF2, the main cellular regulator of the antioxidant response.

Myotonic Muscular Dystrophies

PURPOSE OF REVIEW

This article describes the clinical features, pathogenesis, prevalence, diagnosis, and management of myotonic dystrophy type 1 and myotonic dystrophy type 2.

RECENT FINDINGS

The prevalence of myotonic dystrophy type 1 is better understood than the prevalence of myotonic dystrophy type 2, and new evidence indicates that the risk of cancer is increased in patients with the myotonic dystrophies. In addition, descriptions of the clinical symptoms and relative risks of comorbidities such as cardiac arrhythmias associated with myotonic dystrophy type 1 have been improved.

SUMMARY

Myotonic dystrophy type 1 and myotonic dystrophy type 2 are both characterized by progressive muscle weakness, early-onset cataracts, and myotonia. However, both disorders have multisystem manifestations that require a comprehensive management plan. While no disease-modifying therapies have yet been identified, advances in therapeutic development have a promising future.

Recognition of emotions conveyed by facial expression and body postures in myotonic dystrophy (DM)

INTRODUCTION

Neuromuscular diseases may be of neuropsychological interest insofar as they may affect representations based on embodied cognition theories. Previous studies have shown impaired ability to recognize facial emotions and an association between facial emotion recognition and visuospatial abilities in myotonic dystrophy type 1 (DM1) patients. Here we examined the ability of both DM1 and DM2 patients to recognize emotions expressed by body postures and its relation, and their association with cognitive performance.

METHODS

Participants included 34 DM1 patients, 8 DM2 patients, and 24 healthy control subjects. Emotional recognition ability was assessed through two computerized matching tasks (face and bodies). A neuropsychological battery was used to measure cognition in three domains and global cognition. We used univariate and adjusted linear regression models to investigate the association between cognition and emotion recognition performance.

RESULTS

DM patients (combined DM1 and DM2) performed worse on emotional facial expression (p = .006) and body posture (p = .004) accuracy measures than healthy controls. In linear regression models, DM patients' facial expression accuracy was associated with executive function (p = .013) and visuospatial (p < .001) z-scores. Body posture accuracy was associated with visuospatial (p = .001) and memory (p = .012) z-scores. There were no associations among controls or between cognition and reaction time.

DISCUSSION

These findings suggest that impaired emotional recognition among DM patients is also extended to emotions conveyed by body postures. Consistent with embodied cognition theories, people affected in their body and its movement may have impaired sensorimotor representation in ways that have yet to be fully understood.

Myotonic dystrophy type 1 accompanied with normal pressure hydrocephalus: a case report and literature review

Background

Myotonic dystrophy type 1 (DM1) is the most common disease that can cause muscle weakness and atrophy among adults. Normal pressure hydrocephalus (NPH) is characterized by the triad of gait disturbance, cognitive impairment and urinary incontinence. The association between DM1 and NPH is extremely rare. We report a Chinese female patient with DM1 in association with NPH.

Case presentation

The patient presented with a history of 3-year of walking instability and cognitive impairment. Her brain MRI showed ventriculomegaly with normal cerebrospinal fluid (CSF) pressure and the CSF tap-test was positive, which indicated the diagnosis of probable NPH. DM1 was confirmed by genetic testing.

Conclusions

Four patients with DM1-NPH association were found before. The association between NPH and DM1 may not be just a coincidence, NPH may occur in DM1 later in life and it is vital to recognize the association as a shunt surgery may improve patients’ quality of life.

Towards Central Nervous System Involvement in Adults with Hereditary Myopathies

There is increasing evidence of central nervous system involvement in numerous neuromuscular disorders primarily considered diseases of skeletal muscle. Our knowledge on cerebral affection in myopathies is expanding continuously due to a better understanding of the genetic background and underlying pathophysiological mechanisms. Intriguingly, there is a remarkable overlap of brain pathology in muscular diseases with pathomechanisms involved in neurodegenerative or neurodevelopmental disorders. A rapid progress in advanced neuroimaging techniques results in further detailed insight into structural and functional cerebral abnormalities. The spectrum of clinical manifestations is broad and includes movement disorders, neurovascular complications, paroxysmal neurological symptoms like migraine and epileptic seizures, but also behavioural abnormalities and cognitive dysfunction. Cerebral involvement implies a high socio-economic and personal burden in adult patients sometimes exceeding the everyday challenges associated with muscle weakness. It is especially important to clarify the nature and natural history of brain affection against the background of upcoming specific treatment regimen in hereditary myopathies that should address the brain as a secondary target. This review aims to highlight the character and extent of central nervous system involvement in patients with hereditary myopathies manifesting in adulthood, however also includes some childhood-onset diseases with brain abnormalities that transfer into adult neurological care.

Look at the cognitive deficits in patients with myotonic dystrophy type 1: an exploratory research on the effects of virtual reality

Myotonic dystrophy type 1 is a neuromuscular disease, characterized by a progressive loss of strength, muscle stiffness, and difficulty in relaxation. Myotonic dystrophy type 1 patients can present several neuropsychological deficits, as well as anxiety and mood disorders. Aim of this study is to evaluate the feasibility and the effect of virtual reality in the cognitive and behavioral recovery of myotonic dystrophy type 1 patients. Eleven patients (8 female and 3 male) underwent a specific cognitive rehabilitation program including a conventional neuropsychological treatment followed by a virtual reality neurorehabilitation training using the Virtual Reality Rehabilitation System (Khymeia, Italy). Virtual reality improved many cognitive domains, including executive function, attention, verbal and visuo-spatial abilities, as well as mood and coping strategies. Due to the high prevalence of neuropsychological symptoms in patients with myotonic dystrophy type 1, cognitive rehabilitation should enter into the framework of these patients to potentially boost cognitive and behavioral function and improve quality of life.

Regional brain atrophy in gray and white matter is associated with cognitive impairment in Myotonic Dystrophy type 1

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Predominance of white matter impairment in DM1 is questioned.

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Age poses vulnerability to grey matter loss in specific areas in DM1.

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White matter alterations in DM1 may be developmental.

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Muscular and genetic features are associated with brain abnormalities in DM1.

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Neuropsychology is an unspecific but strong predictor of gray matter damage in DM1.

Background

Myotonic Dystrophy type 1 (DM1) is a slowly progressive myopathy characterized by varying multisystemic involvement. Several cerebral features such as brain atrophy, ventricular enlargement, and white matter lesions (WMLs) have frequently been described. The aim of this study is to investigate the structural organization of the brain that defines the disease through multimodal imaging analysis, and to analyze the relation between structural cerebral changes and DM1 clinical and neuropsychological profiles.

Method

31 DM1 patients and 57 healthy controls underwent an MRI scan protocol, including T1, T2 and DTI. Global gray matter (GM), global white matter (WM), and voxel-level Voxel Based Morphometry (VBM) and voxel-level microstructural WM abnormalities through Diffusion Tensor Imaging (DTI) were assessed through group comparisons and linear regression analysis with age, degree of muscular impairment (MIRS score), CTG expansion size and neuropsychological outcomes from a comprehensive assessment.

Results

Compared with healthy controls, DM1 patients showed a reduction in both global GM and WM volume; and further regional GM decrease in specific primary sensory, multi-sensory and association cortical regions. Fractional anisotropy (FA) was reduced in both total brain and regional analysis, being most marked in frontal, paralimbic, temporal cortex, and subcortical regions. Higher ratings on muscular impairment and longer CTG expansion sizes predicted a greater volume decrease in GM and lower FA values. Age predicted global GM reduction, specifically in parietal regions. At the cognitive level, the DM1 group showed significant negative correlations between IQ estimate, visuoconstructive and executive neuropsychological scores and both global and regional volume decrease, mainly distributed in the frontal, parietal and subcortical regions.

Conclusions

In this study, we describe the structural brain signatures that delineate the involvement of the CNS in DM1. We show that specific sensory and multi-sensory — as well as frontal cortical areas — display potential vulnerability associated with the hypothesized neurodegenerative nature of DM1 brain abnormalities.

Clinical and genetic characteristics of childhood-onset myotonic dystrophy

INTRODUCTION

Myotonic dystrophy type 1 (DM1) is caused by a CTG (cytosine-thymine-guanine) trinucleotide repeat expansion. Congenital DM (CDM) presents in the first month of life, whereas individuals with infantile and juvenile DM1 have later onset of symptoms.

METHODS

We performed a retrospective chart review of patients with childhood-onset DM1 seen at one of three locations in Dallas, Texas between 1990 and 2018. Symptoms, disease course, cognitive features, and family history were reviewed.

RESULTS

Seventy-four patients were included; CDM was diagnosed in 52 patients. There was maternal inheritance in 74% of patients. CTG repeat number ranged from 143 to 2300. Neuropsychiatric and cognitive deficits were common. Over half of the patients had GI disturbances, and orthopedic complications were common.

DISCUSSION

Myotonic dystrophy type 1 in children requires a multidisciplinary approach to management. Presenting symptoms vary, and repeat expansion size does not necessarily directly relate to severity of symptoms. A consensus for outcome measures is required.

Cognitive and adaptive functioning in congenital and childhood forms of myotonic dystrophy type 1: a longitudinal study

AIM

To conduct a longitudinal follow-up of the development of global cognitive abilities and adaptive skills in individuals with congenital and childhood forms of myotonic dystrophy type 1 (DM1).

METHOD

Fifty-one participants (29 males, 22 females, mean age 19y 5mo, SD 4y 11mo, range 10y 10mo-28y 11mo) were divided into severe congenital (n=16), mild congenital (n=17), and childhood DM1 (n=18) subgroups. The average time between the first and second assessments was 7 years 8 months. Adaptive skills were evaluated using the Vineland Adaptive Behavior Scales and global cognitive functioning using Wechsler scales.

RESULTS

There was no statistically significant decline in cognitive abilities and adaptive behaviour. A tendency of decline regarding the level of intellectual disability was found in the congenital DM1 groups but not in the childhood group. In the congenital DM1 groups, the gap in relation to typically developing peers in cognitive and adaptive functioning increased. Predictors of change over time in adaptive skills were age and current level of intellectual disability: individuals with severe intellectual disability and younger individuals deteriorated the most. However, when raw scores were compared, no actual regression in adaptive functioning was found.

INTERPRETATION

The participants had not lost any important adaptive skills. Greater cognitive and adaptive development was found in the childhood group than in the congenital groups.

WHAT THIS PAPER ADDS

There is no absolute decline in cognitive and adaptive abilities in individuals with congenital and childhood myotonic dystrophy type 1. Pace of development is slow in comparison with normative data. The childhood group tended to show greater cognitive and adaptive development than the congenital groups.

High incidence of falls in patients with myotonic dystrophy type 1 and 2: A prospective study

We aimed to examine the incidence as well as the circumstances and the consequences of falling in adult patients with myotonic dystrophy type 1 and 2 (DM1/DM2). We performed a prospective cohort study in 209 subjects, of which 102 had DM1, 42 had DM2 and 65 healthy controls. An assessment of their falls was carried out during 100 consecutive days. In addition, falls during the previous year were reported. The primary outcome measure was the number of self-reported falls per participant during these 100 days. The secondary outcome measures included self-reported causes, circumstances and consequences of the falls. Mean (SD) falls per participant in 100 days was seven- to eightfold higher in patients with DM1 (0.74 (0.14)) and DM2 (0.62 (0.20)) compared to the controls (0.09 (0.04); p < 0.001)). Sixteen percent of DM1 and 17% of DM2 patients fell at least twice. Two-thirds of the falls occurred inside. Fifty percent of falls resulted in an injury, including a head trauma in four patients. Compared to non-fallers, those patients who fell were older (DM1/DM2), had a lower DM1-Activ score (DM1), had more muscle weakness (DM1), and reported less confidence in balance (DM1). This study demonstrates a high incidence and clinical relevance of falling in patients with DM1 and DM2. Fall prevention strategies in both DM1 and DM2 should focus on adaptations of the home environment and the patient's interaction in this environment.

Age-related cognitive decline in myotonic dystrophy type 1: An 11-year longitudinal follow-up study

Background

Myotonic dystrophy type 1 (DM1) is an inherited multi‐systemic disease involving the central nervous system (CNS) and is consequently characterized by a range of cognitive impairments. However, whether this cognitive profile progresses over time is still a matter of debate. The aim of this study was to longitudinally assess a DM1 sample, in order to compare, for the first time, this progression with that of a control group. Clinical and socio‐demographic predictive factors potentially implicated in this possible decline are analysed.

Method

Seventy‐five DM1 patients with childhood, juvenile, adult, and late‐onset, and 54 control participants were re‐assessed in an 11‐year follow‐up with a comprehensive neuropsychological battery. The analyses employed were mixed ANOVA for repeated measures to test intergroup comparisons over time and multiple linear regression for predictive variable analysis.

Results

Myotonic dystrophy type 1 patients significantly worsened in visuospatial/visuoconstructive abilities and visual memory compared with controls. Multiple linear regression revealed that progression of cognitive impairment measured by copy of the Rey–Osterrieth complex figure was predicted by muscular impairment, whilst on the block design test age predicted the change with a cut‐off at 31 years of age.

Discussion

A domain‐specific progressive cognitive decline was found in DM1, with visuospatial/visuoconstructive abilities showing the greatest vulnerability to the passage of time. In addition to important clinical implications, these results suggest the need for the scientific community to delve deeper into the potential mechanisms underlying early cognitive decline in this population.

Differences in the pattern of cognitive impairments between juvenile and adult onset myotonic dystrophy type 1

OBJECTIVE

To understand the different patterns of neuropsychological dysfunction observed between juvenile onset (jDM1) and adult onset (aDM1) myotonic dystrophy type 1.

METHOD

We enrolled 19 genetically confirmed DM1 patients, and neuropsychological tests-Wechsler Adult Intelligence Scale-Revised short form; Rey-Kim memory test; and Executive Intelligence Test for evaluating intelligence, memory, and executive function-were performed. Clinical parameters including cytosine-thymine-guanine (CTG) repeats, creatinine kinase level, pulmonary function test, six-minute walk test, motor scales, and cardiac function were evaluated.

RESULTS

Verbal intelligence was significantly lower in the jDM1 than the aDM1 group (7.50 ± 1.64 vs. 11.00 ± 2.54, respectively; p = 0.009), while no difference was observed in performance intelligence. There was significant differences between the two groups (p = 0.022) with respect to memory function, as specifically revealed by the pattern of lower function in the verbal memory of the jDM1 group. However, the executive function test showed no intergroup differences.

CONCLUSION

Verbal memory impairment significantly deteriorated in the jDM1 group as compared to the aDM1 group, reflecting a more profound neurodevelopmental change in the juvenile type.

Uncovering health and social care needs among myotonic dystrophy patients: Utility of the Needs and Provisions Complexity Scale

OBJECTIVES

Myotonic dystrophy type 1 (DM1) is a slowly progressive multisystem disorder. Guidelines recommend multidisciplinary follow-up. We aimed to investigate the presence of unmet health and social care needs among patients with DM1 and whether unmet needs correlated with motor function, cognitive impairments, or quality of life.

MATERIAL AND METHODS

Patients were 22 adults with DM1. "Needs and Provisions Complexity Scale" (NPCS) was applied to evaluate the individual's needs and provision of health and social services. The Muscular Impairment Rating Scale (MIRS) was used to measure motor function and disease stage. All patients underwent neuropsychological testing. The EQ-5D-3L questionnaire was used to evaluate the patients' health-related quality of life (HRQoL).

RESULTS

Median time from diagnosis was 11 years (range: 1-40). Twenty patients had developed needs related to social care, personal care, and rehabilitation that had not been met, whereas need for medical follow-up was largely met. The more pronounced the muscular impairment, the more unmet needs were experienced by DM1 patients (r = 0.50, P = 0.019). Degree of unmet needs did not correlate with full-scale IQ (r = -0.27, P = 0.23) or HRQoL (r = -0.14, P = 0.55).

CONCLUSION

Using NPCS, we discovered that patients with DM1 had unmet needs with respect to social care, personal care, and rehabilitation although their need for medical follow-up was met. Thus, the use of NPCS helped bring our practice in better accordance with guidelines. A higher MIRS grade should alert the clinician to the likelihood of unmet needs.