Cognitive and psychiatric evaluation of 40 patients with myotonic dystrophy

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.

Mbnl2 loss alters novel context processing and impairs object recognition memory

Patients with myotonic dystrophy type I (DM1) demonstrate visuospatial dysfunction and impaired performance in tasks requiring recognition or memory of figures and objects. In DM1, CUG expansion RNAs inactivate the muscleblind-like (MBNL) proteins. We show that constitutive Mbnl2 inactivation in Mbnl2ΔE2/ΔE2 mice selectively impairs object recognition memory in the novel object recognition test. When exploring the context of a novel arena in which the objects are later encountered, the Mbnl2ΔE2/ΔE2 dorsal hippocampus responds with a lack of enrichment for learning and memory-related pathways, mounting instead transcriptome alterations predicted to impair growth and neuron viability. In Mbnl2ΔE2/ΔE2 mice, saturation effects may prevent deployment of a functionally relevant transcriptome response during novel context exploration. Post-novel context exploration alterations in genes implicated in tauopathy and dementia are observed in the Mbnl2ΔE2/ΔE2 dorsal hippocampus. Thus, MBNL2 inactivation in patients with DM1 may alter novel context processing in the dorsal hippocampus and impair object recognition memory.

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.

Affective symptoms and apathy in myotonic dystrophy type 1 a systematic review and meta-analysis

BACKGROUND

To gain insight into the prevalence of apathy, depression and anxiety symptoms in myotonic dystrophy type 1 (DM1) patients on the basis of a systematic review with a meta-analysis.

METHODS

One author systematically searched and selected studies from Embase, Medline, PsychInfo and Web of Science (index periods up to August 2018). Data extraction and bias assessment were performed independently by two authors. We calculated (1) a weighted pooled prevalence and (2) weighted pooled standardized mean difference (Hedges' g) from studies comparing DM1 patients to healthy and/or neuromuscular disease controls separately for symptoms of depression, anxiety and apathy.

RESULTS

The pooled prevalences of depression (26 studies, n = 1267 DM1 patients), anxiety (19 studies, n = 896) and apathy (5 studies, n = 428), were 18% (95%CI: 12-25), 16 (95%CI: 13-18) and 55% (95%CI: 50-60), respectively. Effect sizes (Hedges' g) for depression, anxiety and apathy in DM1 patients compared to healthy controls were 1.04 (95%-CI: 0.71 to 1.37), 0.87 (95%-CI: 0.51 to 1.24) and 1.13 (95%-CI:0.54-1.71). Effect sizes for symptoms of depression, anxiety and apathy were 0.29 (95% CI: -0.12 to 0.70), 0.45 (95%-CI: -0.31 to 1.22) and 1.12 (95%-CI: 0.32-1.93) for DM1 patients versus neuromuscular disease controls. In most analyses, statistical heterogeneity was high.

CONCLUSIONS

Estimated pooled prevalences of clinically significant levels of symptoms of depression, anxiety and apathy in DM1 are 19, 17 and 55% respectively. Symptoms of depression and anxiety in DM1 may reflect reactive adjustment to progressive impairment and restricted participation similar to other chronic neuromuscular disease. The literature on the prevalence and severity of apathy, although a clinically relevant and characteristic symptom of DM1, is relatively scarce.

A Review of Psychopathology Features, Personality, and Coping in Myotonic Dystrophy Type 1

BACKGROUND

The last literature review on psychopathological features in Myotonic Dystrophy type 1 had been conducted by Ambrosini and Nurnberg in 1979. Since that date, many researches had been carried out.

OBJECTIVE

The aim of this study is (i) to systematically obtain and evaluate the relevant literature on psychopathological features, personality, and coping in individuals with adult phenotypes of Myotonic Dystrophy type 1. (ii) To summarize current research findings and draw conclusions for future research.

METHODS

A systematic search was conducted on Pubmed, PubPsych, PsycInfo, Science Direct, and Scopus covering the period of January 1979 to July 2017.

RESULTS

In view of our literature review, patients show mild psychopathological problems, such as interpersonal difficulties, lack of interest, dysphoria, concern about bodily functioning, and hypersensibility. However, they do not experience more psychiatric disorder in comparison to the general population, except for personality disorders and depression. We discussed problems concerning depression's assessment tool. Patients also present symptoms of several personality disorders: avoidant personality disorder was the most common. Finally, coping strategies relative to limitations resulting from their disease have a negative impact on their quality of life.

CONCLUSIONS

In conclusion, Myotonic Dystrophy type 1 patients did not present homogeneous psychopathological and psychological features. However, based on tendencies observed among Myotonic Dystrophy type 1 patients, elements to conceptualize their social difficulties are provided.

Neuropsychological and Psychological Functioning Aspects in Myotonic Dystrophy Type 1 Patients in Italy

Introduction: Myotonic Dystrophy Type 1 (DM1) is an autosomal dominant genetic illness, characterized by a progressive loss of strength. Important deficits in cognitive functioning and a significant prevalence of psychiatric disorders have been previously reported.

Methods:A neuropsychological and psychological assessment was carried out in 31 DM1 patients (61% males) in order to measure the cognitive functioning and explore their personality profiles. The MMSE Mini-Mental State Examination, Frontal Assessment Battery (FAB), ENB-2 Battery assessing memory (short term, long term and working memory), integration capacities, visual-spatial ability, attention (selective, divided, shifting/switching) executive functions, praxis, discrimination and logic capabilities and psychopathology Symptom Check List 90-R (SCL-90-R) were administered. The neuropsychological and psychological evaluation of DM1 patients was carried out taking into consideration the clinical parameters (CTG repeat, age at onset, disease duration, Muscular Impairment Rate Scale (MIRS), Medical Research Council Scale (MRC) and the Epworth Sleepiness Scales (EPS)).

Results: Regarding psychopathology 19.4% of patients scored a moderate or high level of symptoms intensity index (GSI), 12.9% reported a high number of symptoms (PST) and 16.1% reported a high intensity level of the perceived symptoms (PSDI). Fatigue and daytime sleepiness resulted as being associated with higher levels of psychoticism (PSY). Only 1 patient reported a severe impairment in the spatial and temporal orientation, memory, language, praxis, attention and calculation. Longer disease duration was also associated with cognitive impairment evaluated through ENB-2 (p < 0.05).

Discussions and Conclusions:There are indications of the utility of neuropsychological and psychological screening and support for these patients and their families due to the link between disease duration and cognitive performances. A proposal of a clinical protocol, with an illustration of a clinical case report of a family is presented.

Psychological characteristics of patients with myotonic dystrophy type 1

OBJECTIVES

Myotonic dystrophy type 1 (DM1) is the most common adult-onset muscular dystrophy. It is associated with motor symptoms but patients also display non-motor symptoms such as particular personality traits. Studies have reported mixed results about personality characteristics which may be attributable to small sample sizes, different disease severity of groups studied, and use of different questionnaires or method. This study aimed to describe the psychological characteristics of a large cohort of patients with DM1, to characterize those at risk of developing a psychiatric disorder, and to compare characteristics between two DM1 phenotypes, a mild and more severe adult-onset phenotype.

METHODS

Two hundred patients with DM1 (152 adult-onset; 48 mild) were asked to complete questionnaires assessing personality traits, psychological symptoms, self-esteem, and suicidal risk. Neurological and neuropsychological assessments were performed to compare personality characteristics to clinical and cognitive measures.

RESULTS

Patients with DM1 globally showed personality traits and psychological symptoms in the average range compared to normative data, with normal levels of self-esteem and suicidal ideation. However, 27% of patients were found to be at high risk of developing a psychiatric disorder. Moreover, psychological traits differed across phenotypes, with the most severe phenotype tending to show more severe psychological symptoms. The presence of higher phobic anxiety and lower self-esteem was associated with lower education, a higher number of CTG repeats, more severe muscular impairment, and lower cognitive functioning (P < 0.001).

CONCLUSIONS

Different phenotypes should thus be taken into account in clinical settings for individual management of patients and optimizing therapeutic success.

Muscleblind1, but not Dmpk or Six5, contributes to a complex phenotype of muscular and motivational deficits in mouse models of myotonic dystrophy

Assessment of molecular defects that underlie cognitive deficits observed in mendelian disorders provides a unique opportunity to identify key regulators of human cognition. Congenital Myotonic Dystrophy 1 (cDM1), a multi-system disorder is characterized by both cognitive deficits and a spectrum of behavioral abnormalities, which include visuo-spatial memory deficits, anxiety and apathy. Decreased levels of DMPK (Dystrophia Myotonica-protein kinase), SIX5, a transcription factor or MBNL1 (Muscleblind-like 1), an RNA splice regulator have been demonstrated to contribute to distinct features of cDM1. Mouse strains in which either Dmpk, Six5 or Mbnl1 are inactivated were therefore studied to determine the relative contribution of each gene to these cognitive functions. The open field and elevated plus maze tasks were used to examine anxiety, sucrose consumption was used to assess motivation, whereas the water maze and context fear conditioning were used to examine spatial learning and memory. Cognitive and behavioral abnormalities were observed only in Mbnl1 deficient mice, which demonstrate behavior consistent with motivational deficits in the Morris water maze, a complex visuo-spatial task and in the sucrose consumption test for anhedonia. All three models of cDM1 exhibit normal spatial learning and memory. These data identify MBNL1 as a potential regulator of emotional state with decreased MBNL1 levels underlying the motivational deficits observed in cDM1.

Toward understanding cognitive impairment in patients with myotonic dystrophy type 1

Cognitive dysfunction and sleep disruption are two frequent but underestimated features of adult onset myotonic dystrophy type 1 (MD1). In order to investigate the MD1 cognitive profile and its relationship with sleep disruption, 23 patients with genetically proved MD1 (mild-moderate in severity) underwent neuropsychological (nps) and polysomnography assessment. Patients scored lower than controls on almost all nps tests but cognitive impairments were mostly observed in executive functions (z-score = -2.14), with complex attention (z-score = -1.04), memory (z-score = -0.65), constructions (z-score = -1.29), and reasoning (z-score = -0.75) being slightly affected. Moderate-severe sleep apnea (apnea-hypopnea index [AHI] > or =15) was very frequent with most of the apneas being of the obstructive type. However, we found hardly any evidence of association between subjective, objective sleep parameters, and nps performance (p > .001). Thus, in our cohort of 23 adult MD1 patients, mild cognitive dysfunction, which is mostly related to the dysfunction of frontal association cortex and its underlying neural networks, does not seem to be significantly influenced by sleep disruption, which is mainly caused by obstructive apnea events.

Cerebral involvement in myotonic dystrophies

Myotonic dystrophy types 1 (DM1) and 2 (DM2) are similar yet distinct autosomal-dominant disorders characterized by muscle weakness, myotonia, cataracts, and multiple organ involvement, including the brain. One key difference between DM1 and DM2 is that a congenital form has been described for DM1 only. Expression of RNA transcripts containing pathogenic repeat lengths produces defects in alternative splicing of multiple RNAs, sequesters specific repeat-binding proteins, and ultimately leads to developmentally inappropriate splice products for a particular tissue. Whether brain pathology in its entirety in adult DM1 and DM2 is caused by interference in RNA processing remains to be determined. This review focuses on the similarities and differences between DM1 and DM2 with respect to neuropsychological, neuropathological, and neuroimaging data relating to cerebral involvement, with special emphasis on the clinical relevance and social consequences of such involvement.

Normal pressure hydrocephalus in a patient with myotonic dystrophy: case report with a 10-year follow-up

OBJECTIVE AND IMPORTANCE

Myotonic dystrophy (MD) is the most common adult muscular dystrophy involving multiple organs. Normal pressure hydrocephalus (NPH) is characterized by gait apraxia, urinary incontinence, and dementia. NPH in association with MD has been reported in only three cases. This report provides for the first time the complete evaluation, treatment, and long-term follow-up of a patient with NPH and MD.

CLINICAL PRESENTATION

A 61-year-old man known to have MD complained of 4 years of progressive deterioration of long-term memory and gait disturbance, which was the main clinical feature. Computed tomography scan and magnetic resonance imaging showed ventricular enlargement. Intracranial pressure monitoring showed B waves with amplitude superior to 9 mm Hg in more than 5% of the recording.

TECHNIQUE

We performed a ventriculoperitoneal shunt with clear postoperative improvement, confirming the diagnosis of NPH. The clinical improvement has remained stable through prolonged follow-up.

CONCLUSION

Association between MD and NPH could be more than coincidental, and it is important to recognize this potential insidious association because a ventriculoperitoneal shunt can provide excellent long-term clinical improvement.

Temperament and character in patients with classical myotonic dystrophy type 1 (DM-1)

This study was designed to investigate personality in classical Myotonic Dystrophy (DM-1). Forty-six patients with DM-1 (25 women and 21 men), 31 healthy controls and 37 subjects in a contrast group, consisting of patients with other muscle disorders (spinal muscular atrophy, facioscapulohumeral dystrophy and limb girdle muscular dystrophy), completed the Temperament and Character Inventory (TCI) (Cloninger, 1994). We aimed to establish whether CTG triplet repeat size correlated with ratings of personality dimensions in the TCI. The DM-1 patients scored significantly higher on the TCI dimension Harm avoidance and lower on Persistence, Self-directedness and Cooperativeness. Signs of a personality disorder were found in 20% of the DM-1 patients. No correlation was found between the number of CTG repeats and scores in the TCI. This study indicates deviant personality in classical DM-1 regarding temperament and character, both in comparison to healthy controls and to patients with other muscle disorders with no known brain disorder.

In situ hybridization analysis of Dmpk mRNA in adult mouse tissues

Myotonic dystrophy1 (DM1) is an autosomal dominant, multi-system disorder resulting from a CTG repeat expansion located in the 3' untranslated region of DMPK and immediately in the 5' of SIX5. Skeletal muscle, heart and smooth muscle are prominently affected in DM1. Endocrine abnormalities, gonadal atrophy, brain, skin, skeletal, immune and respiratory defects are also features of the disorder. Both DMPK and SIX5 levels are decreased in DM1 patients. Importantly, expression of mutant mRNAs encoding expanded CUG repeats has been shown to alter the activity of CUG repeat binding proteins in DM1. Mouse models have demonstrated that decreased levels of Dmpk, Six5 and the expression of expanded CUG repeats independently contribute to the development of DM1 pathology. However, an important gap in these studies is a lack of clear understanding of the expression pattern of Dmpk. We demonstrate that Dmpk mRNA is expressed in a range of adult mouse tissues that show pathology in DM1 including skeletal muscle, heart, smooth muscle, bone, testis, pituitary, brain, eye, skin, thymus and lung. Thus DMPK loss or CUG repeat expansion could contribute to DM1 pathology to these tissues. Dmpk mRNA is not detected in the ovary, pancreas or kidney. Significantly, Dmpk mRNA is expressed in the intestinal epithelium, cartilage and liver, which have not been reported to show consistent abnormalities in Dmpk(-/-) mice or in transgenic animals expressing CUG repeats. Taken together these data suggest that Dmpk loss or CUG repeat expression per se may not be sufficient to initiate pathology and are consistent with the hypothesis that coexpression of specific CUG repeat binding proteins with the mutant Dmpk mRNA or deregulation of genes such as Six5 that flank the CTG repeat tract may be necessary for DM1 to manifest.

Cardiovascular autonomic control in myotonic dystrophy type 1: a correlative study with clinical and genetic data

The autonomic nervous system has been evaluated in myotonic dystrophy with contradictory results and its relationship with heart disturbances remains unclear. Twenty-three patients with myotonic dystrophy type 1 were investigated by a battery of six cardiovascular autonomic tests and power spectral analysis of heart rate variability. Although 15 patients (65%) revealed abnormal or borderline results in some tests, only one patient had a definite autonomic damage, as indicated by two or more abnormal tests. As a group, myotonic dystrophy type 1 patients showed a significant reduction of heart rate variability during deep breathing (P < 0.0001). The exclusive involvement of parasympathetic tests suggests that a mild vagal dysfunction occurs in some myotonic dystrophy type 1 patients. The results indicate that such autonomic abnormalities are not: (1) part of a peripheral neuropathy; (2) related to cytosine-thymine-guanine repeat size or breathing pattern. Power spectral analysis showed a reduction of supine low-frequency band, which is, but not exclusively, a marker of sympathetic activity. It was inversely correlated to disease duration (P < 0.04), suggesting a progression as the disease advances. A low-frequency power, recorded after standing, was significantly associated (P < 0.02) with presence of heart involvement. Our findings suggest that a mixed, especially parasympathetic, autonomic dysfunction may occur in myotonic dystrophy type 1, although it is not a major finding. It could play a role in the occurrence of cardiac abnormalities, or increase the risk of sudden cardiovascular events.

Cognitive impairment and (CTG)n expansion in myotonic dystrophy patients

BACKGROUND

Myotonic dystrophy (DM) is a genetic multisystemic disease with muscular, endocrine, ocular, cardiac and cognitive impairment. The molecular basis of the disease has been identified in an unstable base triplet (CTG)n repeat located in the 3' untranslated region of the miotonin protein-kinase (MT-PK) gene on the long arm of chromosome 19. Cognitive impairment could be a direct expression of this genetic alteration at the central nervous system (CNS) level rather than a consequence of the neuromuscular impairment. To explore this hypothesis, we tested a group of genetically diagnosed, adult onset DM, of their nonaffected relatives (NAR), of patients with spinal muscle atrophy (SMA), and of normal controls using the Wechsler Adult Intelligence Scale (WAIS).

METHODS

Seventeen adult-onset DM patients, 9 NAR, 10 SMA patients and 20 unrelated normal controls (NC) were studied. Clinical, neuromuscular and neuropsychiatric evaluation, which included WAIS and the Schedule for Affective Disorders and Schizophrenia (SADS), were performed on the four groups. DM, NAR and NC were also assessed by a neurophysiological (P300) evaluation. A DNA analysis was performed in DM and in NAR to measure presence and magnitude of CTG expansion.

RESULTS

We found a statistically significant difference between verbal (p < .0003), nonverbal (p < .0001) and total (p < .0001) IQ of DM patients compared to IQs of NAR, SMA and NC. Seven out of 11 WAIS subtests were significantly and consistently lower in DM patients compared to SMA and/or NC. In DM patients there was a statistically significant negative correlation between nonverbal (r = -.68; p < .002) and total (r = .59; p < .01) IQ and (CTG)n. Patients with DM had a significantly lower P300 amplitude compared to NAR and NC.

CONCLUSIONS

Our study indicates that in DM there is a mild but significant cognitive impairment which correlates with the degree of CTG expansion and it is not dependent on the neuromuscular impairment; however further studies with larger groups of patients and controls are suggested to confirm our results, due to the small sample size and to a possible effect of educational level in our patients.

Psychopathological and emotional deficits in myotonic dystrophy

OBJECTIVE

To evaluate psychopathological disturbances in patients with myotonic dystrophy (MD) and compare patients with MD to both patients with facioscapulohumeral dystrophy (FSHD) and healthy control subjects.

METHODS

A semistructured interview was used to determine DSM III-R criteria for major depressive episodes, dysthymic episodes, and generalised anxiety. The Montgomery and Asberg and the Hamilton depressive scales, the Covi and Tyrer anxiety scales, the Abrams and Taylor scale for emotional blunting, and the depressive mood scale were all used in the study. Subjects were also asked to complete questionnaires for physical and social anhedonia.

RESULTS

Fifteen patients with MD, 11 patients with FSHD, and 14 healthy subjects were studied. Patients with MD were not more depressed or anxious than healthy controls. Patients with FSHD were the most depressed and most anxious. However, patients with MD had significantly lower scores for expressiveness and significantly higher scores for anhedonia than the other two groups.

CONCLUSION

Patients with MD did not present significant depressive or anxious symptomatology but rather an emotional deficit. This emotional deficit may be an adaptive reaction to the threatening implications of the disease, or the effect of the CNS lesions which occur with MD, or both.

Asperger syndrome associated with Steinert's myotonic dystrophy

Steinert's myotonic dystrophy was diagnosed in a 10-year-old girl with Asperger syndrome. This form of myotonic dystrophy is one of a growing list of genetic diseases that can be diagnosed by analysis of a gene with trinucleotide repeats that may expand. The patient has the largest such expansion known within her pedigree. She has many of the psychological deficits that have been reported in adult-onset myotonic dystrophy. This is the first known report of an association of this disorder with Asperger syndrome. Recently Moebius syndrome has been found in association with disorders of the autistic spectrum; physicians practicing developmental medicine should now also consider Steinert's myotonic dystrophy when evaluating children with facial diplegia.

Intelligence quotient profile in myotonic dystrophy, intergenerational deficit, and correlation with CTG amplification

An abbreviated Wechsler Adult Intelligence Scale Revised (WAIS-R) was used to assess verbal and arithmetical cognitive performance in 55 subjects with myotonic dystrophy (DM), covering all grades of disease severity, and 31 controls at 50% risk of inheriting DM. Scaled scores from the assessment were converted into an intelligence quotient (IQ) estimation on each person. Significant IQ differences were found between: (1) all 55 DM subjects (mean 90.2, SD 16.1) and 31 controls (102.6, SD 9.4), with no sex differences in either group; (2) 15 affected parents (99.3, SD 12.2) and their affected children (88.1, SD 17.2), where significance was dependent on parental sex being female; and (3) 15 pairs of affected sibs (89.6, SD 13.2) and their normal sibs (100.2, SD 7.6). IQ steadily declined as (1) the age of onset of signs and symptoms decreased, and (2) the CTG expansion size increased. The correlation appeared to be more linear with age of onset. The correlation of IQ difference and CTG expansion difference in both the DM parent-child pairs and normal sib-affected sib pairs was poor, indicating that CTG expansion is not a reliable predictor of IQ either in individual persons or families. Further analysis of cognitive function in DM is required to clarify specific deficits characteristic of this patient group.