Changes in mental state and behaviour in Huntington's disease

Pathomechanisms of behavioral abnormalities in Huntington disease: an update

Huntington disease (HD), a devastating autosomal-dominant neurodegenerative disease caused by an expanded CAG trinucleotide repeat, is clinically characterized by a triad of symptoms including involuntary motions, behavior problems and cognitive deficits. Behavioral symptoms with anxiety, irritability, obsessive-compulsive behaviors, apathy and other neuropsychiatric symptoms, occurring in over 50% of HD patients are important features of this disease and contribute to impairment of quality of life, but their pathophysiology is poorly understood. Behavior problems, more frequent than depression, can be manifest before obvious motor symptoms and occur across all HD stages, usually correlated with duration of illness. While specific neuropathological data are missing, the relations between gene expression and behavior have been elucidated in transgenic models of HD. Disruption of interneuronal communications, with involvement of prefronto-striato-thalamic networks and hippocampal dysfunctions produce deficits in multiple behavioral domains. These changes that have been confirmed by multistructural neuroimaging studies are due to a causal cascade linking molecular pathologies (glutamate-mediated excitotoxicity, mitochondrial dysfunctions inducing multiple biochemical and structural alterations) and deficits in multiple behavioral domains. The disruption of large-scale connectivities may explain the variability of behavior profiles and is useful in understanding the biological backgrounds of functional decline in HD. Such findings offer new avenues for targeted treatments in terms of minimizing neurobehavioral impairment in HD.

Prodromal Cognitive Changes as a Prognostic Indicator of Forthcoming Huntington's Disease Severity: A Retrospective Longitudinal Study

BACKGROUND

Cognitive changes in Huntington's disease (HD) precede motor manifestations. ENROLL-HD platform includes four cognitive measures of information processing speed (IPS). Our group is eager to seek clinical markers in the life stage that is as close as possible to the age of onset (ie, the so called prodromal HD phase) because this is the best time for therapeutic interventions.

OBJECTIVES

Our study aimed to test whether cognitive scores in prodromal ENROLL-HD mutation carriers show the potential to predict the severity of motor and behavioral changes once HD became fully manifested.

METHODS

From the global ENROLL-HD cohort of 21,343 participants, we first selected a premanifest Cohort#1 (ie, subjects with Total Motor Score (TMS) <10 and Diagnostic Confidence Level (DCL) <4, N = 1.222). From this cohort, we then focused on a prodromal Cohort#2 of subjects who were ascertained to phenoconvert into manifest HD at follow-up visits (ie, subjects from 6 ≤ TMS≤9 and DCL <4 to TMS≥10 and DCL = 4, n = 206).

RESULTS

The main results of our study showed that low IPS before phenoconversion in Cohort#2 predicted the severity of motor and behavioral manifestations. By combining the four IPS cognitive measures (eg, the Categorical Verbal Fluency Test; Stroop Color Naming Test; Stroop Word Reading; Symbol Digit Modalities Test), we generated a Composite Cognition Score (CCS). The lower the CCS score the higher the TMS and the apathy scores in the same longitudinally followed-up patients after phenoconversion.

CONCLUSIONS

CCS might represent a clinical instrument to predict the prognosis of mutation carriers who are close to manifesting HD.

Neurodegenerative Diseases: New Hopes and Perspectives

Alzheimer's disease, Parkinson's disease, Amyotrophic lateral sclerosis, Huntington's disease, and Friedrich ataxia are all incurable neurodegenerative diseases defined by the continuous progressive loss of distinct neuronal subtypes. Despite their rising prevalence among the world's ageing population, fewer advances have been made in the concurrent massive efforts to develop newer drugs. Recently, there has been a shift in research focus towards the discovery of new therapeutic agents for neurodegenerative diseases. In this review, we have summarized the recently developed therapies and their status in the management of neurodegenerative diseases.

The validation of the Italian version of multiple sclerosis neuropsychological screening questionnaire in Huntington's disease

INTRODUCTION

Multiple sclerosis neuropsychological questionnaire (MSNQ) is a brief questionnaire useful for screening patient's and informant's self-perception of cognitive dysfunctions in daily life activities. Our study aims to evaluate the MSNQ validity in Huntington's disease (HD) mutation carriers and to correlate MSNQ scores with neurological, cognitive, and behavioral variables.

METHODS

The study was conducted on a sample of 107 subjects from presymptomatic to the middle stage of HD recruited at LIRH Foundation and C.S.S. Mendel Institute in Rome. Unified Huntington's Disease Rating Scale (UHDRS), an internationally standardized and validated scale, was used to evaluate motor, functional cognitive, and behavioral domains.

RESULTS

Our results showed that in HD subjects, MSNQ has a unidimensional factor structure. Correlational analyses indicated a good correlation between the MSNQ-patient version (MSNQ-p) and clinical variables, specifically with cognitive dysfunction and behavioral alterations. Moreover, higher scores in MSNQ-p were associated with higher motor disease and functional impairment showing that patients in advanced stage of HD perceive a greater cognitive impairment. These results confirm the questionnaire's reliability.

CONCLUSIONS

The present study demonstrates the validity and adaptability of MSNQ in the HD population proposing it as a cognitive tool during routine clinical follow-ups, although further research is needed to determine an optimal cut-off score for this measure.

Nursing home residents with Huntington's disease: Heterogeneity in characteristics and functioning

BACKGROUND

In Huntington's disease (HD), admission to a nursing home (NH) is required in advanced disease stages. To gain insight in care needs, more knowledge is needed on the functioning of this group.

OBJECTIVE

Describing patient and disease characteristics, their functioning, and gender differences.

METHODS

A cross-sectional descriptive design was used to collect data of 173 patients living in eight Dutch HD-specialized NHs. Data were collected on characteristics and functioning. We tested for gender differences.

RESULTS

Mean age was 58.3 years and 49.7% were men. Activities of daily living and cognition varied from 46 to 49% mildly impaired to 22-23% severely impaired. Communication was severely impaired in 24%. Social functioning was low in 31% and high in 34%. A majority of patients used psychotropic medications (80.3%) and showed neuropsychiatric signs (74%). Women were on average more dependent in ADL (severely impaired 33.3% vs 12.8%), more often depressed (26.4% vs 11.6%), and prescribed antidepressant medications more often (64.4% vs 48.8%) than men.

CONCLUSIONS

The population of HD patients in NHs is heterogeneous in terms of patient and disease characteristics, and functioning. As a consequence, care needs are complex leading to implications for the required expertise of staff to provide adequate care and treatment.

Huntington disease exacerbates action impulses

Background

Impulsivity is a common clinical feature of Huntington disease (HD), but the underlying cognitive dynamics of impulse control in this population have not been well-studied.

Objective

To investigate the temporal dynamics of action impulse control in HD patients using an inhibitory action control task.

Methods

Sixteen motor manifest HD patients and seventeen age-matched healthy controls (HC) completed the action control task. We applied the activation-suppression theoretical model and distributional analytic techniques to differentiate the strength of fast impulses from their top-down suppression.

Results

Overall, HD patients produced slower and less accurate reactions than HCs. HD patients also exhibited an exacerbated interference effect, as evidenced by a greater slowing of RT on non-corresponding compared to corresponding trials. HD patients made more fast, impulsive errors than HC, evidenced by significantly lower accuracy on their fastest reaction time trials. The slope reduction of interference effects as reactions slowed was similar between HD and controls, indicating preserved impulse suppression.

Conclusion

Our results indicate that patients with HD show a greater susceptibility to act rapidly on incorrect motor impulses but preserved proficiency of top-down suppression. Further research is needed to determine how these findings relate to clinical behavioral symptoms.

Development and Psychometric Properties of a New Brief, Yet Comprehensive, Behavioral Questionnaire for Huntington's Disease

Background

Individuals with Huntington's disease (HD) experience motoric, cognitive, and psychiatric dysfunction. These difficulties can cause maladaptive behaviors that can be very distressing to family and caregivers. Capturing these behaviors in clinical and research settings is crucial.

Objectives

To develop and evaluate the psychometric properties of an instrument that is brief, yet comprehensive, in assessing a broad range of behaviors in HD.

Methods

A pool of 30 items encompassing common behaviors in HD was generated. Items were scored on a 4-point Likert scale ranging from completely disagree to completely agree, with higher scores indicating greater dysfunction. The self-report measure was piloted on a small sample of individuals with HD. Reliability (test-retest, internal consistency) and validity (convergent, discriminant, criterion) were evaluated.

Results

The HD-Behavioral Questionnaire (HD-BQ) demonstrated evidence for reliability with a test-retest correlation coefficient of r = 0.81 and an internal consistency of 0.96. Validity was established with evidence for good convergent, divergent, and criterion validity. A receiver operating characteristic curve showed that the HD-BQ outperformed a similar commonly used measure in diagnostic capability of behaviors in HD.

Conclusions

The HD-BQ, a patient self-report measure, was created to more fully explore behavioral issues that people with HD experience in response to limitations of commonly used instruments in the field. Psychometric evidence supports that the HD-BQ is a valid and reliable instrument for the brief, yet comprehensive, assessment of problematic behaviors in HD.

What we don't need to prove but need to do in multidisciplinary treatment and care in Huntington's disease: a position paper

BACKGROUND

Huntington's disease is a complex neurodegenerative hereditary disease with symptoms in all domains of a person's functioning. It begins after a healthy start in life and leads through the relentless progression over many years to complete care dependency and finally death. To date, the disease is incurable. The long progressive complex nature of the disease demands multiple disciplines for treatment and care of patient and family. These health care providers need inter- and multidisciplinary collaboration to persevere and be efficacious in this devastating disease trajectory.

DISCUSSION

The position paper outlines current knowledge and experience alongside the experience and consensus of a recognised group of HD multidisciplinary experts. Additionally the patient's voice is clear and calls for health care providers with a holistic view on patient and family. Building long-term trust is a cornerstone of the network around the patient. This paper describes a managed care network comprising all the needed professionals and services. In the health care system, the role of a central coordinator or case manager is of key importance but lacks an appropriate guideline. Other disciplines currently without guidelines are general practitioners, nurses, psychologists, and social workers. Guidelines for neurologists, psychiatrists, geneticists, occupational therapists, speech and language therapists, physiotherapists, dieticians, and dentists are being discussed. Apart from all these profession-specific guidelines, distinctive inter- and multidisciplinary collaboration requirements must be met.

CONCLUSIONS AND RECOMMENDATIONS

The complex nature of Huntington's disease demands multidisciplinary treatment and care endorsed by international regulations and the lay association. Available guidelines as reviewed in this paper should be used, made available by a central body, and updated every 3-5 years. Time needs to be invested in developing missing guidelines but the lack of this 'proof' should not prevent the 'doing' of good care.

Disgust as a transdiagnostic index of mental illness: A narrative review of clinical populations

Disgust is a basic emotion of rejection, providing an ancestral defensive mechanism against illness. Based on research that documents altered experiences of disgust across several psychopathological conditions, we conducted a narrative review to address the hypothesis that altered disgust may serve as a transdiagnostic index of mental illness. Our synthesis of the literature from past decades suggests that, compared to healthy populations, patients with mental disorders exhibit abnormal processing of disgust in at least one of the analyzed dimensions. We also outline evidence of alterations in brain areas relevant to disgust processing, such as the insula and the interconnected limbic network. Overall, we provide preliminary support for the hypothesis that altered disgust processing may serve as a transdiagnostic index of mental illness.

The risk of criminal behavior in the elderly and patients with neurodegenerative disease

Behavioral changes are commonly observed in patients with dementia and can lead to criminal offenses, even without a history of criminal or antisocial behavior. Due to the growth of the aging population, this poses a rising problem to deal with for the criminal justice system and in general for society. Criminal behavior may include minor crimes such as theft or traffic violations, but also serious crimes such as physical abuse, sexual offense, or murder. In the assessment of criminal behavior among elderly (first-time) offenders, it is important to be aware of possible neurodegenerative diseases at the time of the crime. This book chapter provides an overview on criminal behavior in the elderly and specifically discusses existing literature on patients suffering from a neurodegenerative disease, including Alzheimer disease, vascular dementia, frontotemporal dementia, Parkinson disease, and Huntington disease. Each section is introduced by a true case to illustrate how the presence of a neurodegenerative disease may affect the criminal judgment. The chapter ends with a summary, multifactorial model of crime risk, future perspectives, and concluding remarks.

Immunomodulation in age-related disorders and nanotechnology interventions

Recently, the aging population has increased exponentially around the globe bringing more challenges to improve quality of life in those populations while reducing the economic burden on healthcare systems. Aging is associated with changes in the immune system culminating in detrimental effects such as immune dysfunction, immunosenescence, and chronic inflammation. Age-related decline of immune functions is associated with various pathologies including cardiovascular, autoimmune, neurodegenerative, and infectious diseases to name a few. Conventional treatment addresses the onset of age-related diseases by early detection of risk factors, administration of vaccines as preventive care, immunomodulatory treatment, and other dietary supplements. However, these approaches often come with systemic side-effects, low bioavailability of therapeutic agents, and poor outcomes seen in the elderly. Recent innovations in nanotechnology have led to the development of novel biomaterials/nanomaterials, which explore targeted drug delivery and immunomodulatory interactions in vivo. Current nanotechnology-based immunomodulatory approaches that have the potential to be used as therapeutic interventions for some prominent age-related diseases are discussed here. Finally, we explore challenges and future aspects of nanotechnology in the treatments of age-related disorders to improve quality of life in the elderly. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Cardiovascular Disease Therapeutic Approaches and Drug Discovery > Nanomedicine for Neurological Disease Therapeutic Approaches and Drug Discovery > Emerging Technologies.

Alteration of Autophagy and Glial Activity in Nilotinib-Treated Huntington's Disease Patients

Nilotinib is a tyrosine kinase inhibitor that is safe and tolerated in neurodegeneration, it achieves CSF concentration that is adequate to inhibit discoidin domain receptor (DDR)-1. Nilotinib significantly affects dopamine metabolites, including Homovanillic acid (HVA), resulting in an increase in brain dopamine. HD is a hereditary disease caused by mutations in the Huntingtin's (HTT) gene and characterized by neurodegeneration and motor and behavioral symptoms that are associated with activation of dopamine receptors. We explored the effects of a low dose of nilotinib (150 mg) on behavioral changes and motor symptoms in manifest HD patients and examined the effects of nilotinib on several brain mechanisms, including dopamine transmission and gene expression via cerebrospinal fluid (CSF) miRNA sequencing. Nilotinib, 150 mg, did not result in any behavioral changes, although it significantly attenuated HVA levels, suggesting reduction of dopamine catabolism. There was no significant change in HTT, phosphorylated neuro-filament and inflammatory markers in the CSF and plasma via immunoassays. Whole miRNA genome sequencing of the CSF revealed significant longitudinal changes in miRNAs that control specific genes associated with autophagy, inflammation, microglial activity and basal ganglia neurotransmitters, including dopamine and serotonin.

Informal care in Huntington's disease: Assessment of objective-subjective burden and its associated risk and protective factors

BACKGROUND

Because of the genetic transmission of Huntington's disease (HD), informal caregivers (ICs, i.e., non-professional caregivers) might experience consecutive and/or concurrent caregiving roles to support several symptomatic relatives with HD over their life. Additionally, some ICs might be HD carriers. However, whether family burden of care is associated with specific factors in HD remains poorly studied.

OBJECTIVE

To provide a quantitative view of the IC burden and identify associated factors.

METHODS

This was a cross-sectional assessment of home-dwelling symptomatic HD individuals (from REGISTRY and Bio-HD studies) and their primary adult ICs, including the HD individual's motor, cognitive, behavioral, functional Unified Huntington's Disease Rating Scale score; IC objective burden (quantification of IC time in activities of daily living, instrumental activities of daily living and supervision, using the Resource Utilization in Dementia instrument), IC subjective burden (Zarit Burden Inventory), and ICs' social economic functioning and use of professional home care.

RESULTS

We included 80 ICs (mean [SD] age 57 [12.9] years, 60% women) in charge of 80 individuals with early to advanced stage HD (mean age 56 [12.6] years, 51% men). The mean hours of informal care time was high: 7.3 (7.9) h/day (range 0-24); the mean professional home care was 2.8 (2.8) h/day (range 0.1-12.3). This objective burden increased with higher functional loss of the HD individual and with more severe cognitive-behavioral disorders. The mean subjective burden (35.4 [17.8], range 4-73) showed a high level since the earliest stage of HD; it was associated with HD duration (mean 9.2 [4.7] years) and with aggressive symptoms in individuals (44% of cases). The burden was partially related to the multiplex caregiving status (19%). Protective factors lowering the IC burden included the absence of financial hardship (57%), a strong social network (16%) and keeping active on the job market outside home (46%).

CONCLUSIONS

The objective-subjective burden of ICs related to changing patterns of neuro-psychiatric symptoms and mitigating environmental characteristics around the HD individual-caregiver dyads.

Psychotropic medication use in Huntington's disease: A retrospective cohort study

BACKGROUND

Whereas the treatment of motor symptoms in Huntington's disease (HD) receives much attention, less is known about the treatment of neuropsychiatric symptoms.

OBJECTIVE

We aim to give an overview of psychotropic drug use in the treatment of neuropsychiatric symptoms across disease stages in HD.

METHODS

We conducted a descriptive cross-sectional study of psychotropic drug prescriptions in a large longitudinal database of HD patients, Enroll HD. Across disease stages, the number of prescriptions per medication class, as well as the registered indications for these prescriptions were listed, and compared with that in gene negative participants.

RESULTS

Of the 8967 included HD patients, 80% were using at least one psychotropic drug, compared to 27% of gene negative participants. In HD patients, 51% of all drug prescriptions was for psychotropic drugs. The average number of psychotropic drugs used per patient increased from 1.3 in the premanifest stage to 2.5 in stage 5. With progressing disease stages, the proportion of antidepressant drug prescriptions gradually decreased from 74.1% of all prescriptions to 27.3%, and antipsychotic drug prescriptions increased from 7.0% to 38.7%. In line with this, depression and anxiety as listed indications for prescription decreased with advancing disease stages (from 63.0% to 31.5% and from 30.0% to 15.4% respectively), whereas irritability and psychosis increased (from 3.1% to 28.6% and from 0.9% to 16.0% respectively).

CONCLUSIONS

Psychotropic medication is widely prescribed in HD, for various indications. Antidepressant use decreases proportionally and antipsychotic use increases with advancing disease stages, suggesting a relative decrease in prevalence of anxiety and depression over disease stages on one hand, and a relative increase in prevalence of irritability and delusions on the other.

Primary Palliative Care in Huntington's Disease

Background

Palliative care practices, including communication about patient-centered goals of care and advance care planning (ACP), have the potential to enhance care throughout the course of Huntington's disease (HD) and related disorders. The goal of our project was to develop a pilot program that integrates primary palliative care practices with interdisciplinary care for HD.

Objectives

(1) To train HD team members to facilitate goals of care and ACP conversations at all stages of HD; (2) To create materials for care planning in HD focused on patient-centered goals of care and health-related quality of life; and (3) To modify clinic workflow to include goals of care and ACP discussions.

Methods

We defined planning domains to expand care planning beyond end-of-life concerns. We created a patient and family guide to advance care planning in HD. We conducted VitalTalk communications training with the HD team. We modified the interdisciplinary clinic workflow to include ACP and developed an EMR template for documentation.

Results

After communication training, more team members felt well prepared to discuss serious news (12.5% to 50%) and manage difficult conversations (25% to 62.5%). The proportion of clinic visits including advance care planning discussions increased from 12.5% to 30.6% during the pilot phase.

Conclusions

Provision of primary palliative care for HD in an interdisciplinary clinic is feasible. Integration of palliative care practices into HD specialty care requires additional training and modification of clinic operations.

Pathogenesis of Huntington's Disease: An Emphasis on Molecular Pathways and Prevention by Natural Remedies

BACKGROUND

Huntington's disease is an inherited autosomal dominant trait neuro-degenerative disorder caused by changes (mutations) of a gene called huntingtin (htt) that is located on the short arm (p) of chromosome 4, CAG expansion mutation. It is characterized by unusual movements, cognitive and psychiatric disorders.

OBJECTIVE

This review was undertaken to apprehend biological pathways of Huntington's disease (HD) pathogenesis and its management by nature-derived products. Natural products can be lucrative for the management of HD as it shows protection against HD in pre-clinical trials. Advanced research is still required to assess the therapeutic effectiveness of the known organic products and their isolated compounds in HD experimental models.

SUMMARY

Degeneration of neurons in Huntington's disease is distinguished by progressive loss of motor coordination and muscle function. This is due to the expansion of CAG trinucleotide in the first exon of the htt gene responsible for neuronal death and neuronal network degeneration in the brain. It is believed that the factors such as molecular genetics, oxidative stress, excitotoxicity, mitochondrial dysfunction, neuroglia dysfunction, protein aggregation, and altered UPS leads to HD. The defensive effect of the natural product provides therapeutic efficacy against HD. Recent reports on natural drugs have enlightened the protective role against HD via antioxidant, anti-inflammatory, antiapoptotic, and neurofunctional regulation.

On the association between apathy and deficits of social cognition and executive functions in Huntington's disease

OBJECTIVE

To investigate if executive and social cognitive dysfunction was associated with apathy in a large cohort of Huntington's disease gene expansion carriers.

METHOD

Eighty premanifest and motor-manifest Huntington's disease gene expansion carriers (Mini-Mental State Examination score ≥ 24 and Montreal Cognitive Assessment score ≥ 19) and thirty-two controls were examined with the Lille Apathy Rating Scale (LARS), a tailored and quantitative measure of apathy, and a comprehensive cognitive battery on executive functions and social cognition (emotion recognition, theory of mind and sarcasm detection), as well as general correlates like demographic variables, and neuropsychiatric and cognitive screening tests.

RESULTS

The motor-manifest Huntington's disease gene expansion carriers had significantly different scores on most measures of social cognition and executive functions, compared to premanifest and control participants. Apathy was significantly correlated with most executive test scores, but the Emotion Hexagon was the only social cognitive test score significantly correlated with apathy. We found that the motor score and the depression score were the only significant predictors of the apathy score, when the social cognitive and executive tests with the strongest association with the global LARS score were entered into a multiple stepwise regression model. No cognitive test score could significantly predict apathy. The model explained 21 % of the total variance.

CONCLUSION

Despite being significantly correlated with apathy neuropsychological variables did not have a significant impact on apathy when variables as depression and motor symptoms were taken into account. Apathy should be considered an independent symptom of Huntington's disease that requires specific examination.

Huntington's Disease: A Clinical Review

The Huntington's gene on chromosome 4 has a dominantly inherited CAG trinucleotide repeat expansion, ultimately resulting in Huntington's disease (HD), a completely penetrant neurological condition. The frequency is 10-100 times higher in the population descended from Europe than in East Asia. Through various processes, including impairment of proteostasis, transcription, and cell function, as well as direct toxicity of the mutant protein, mutated huntingtin triggers neuronal malfunction and loss at the cellular level. As the disease worsens, the brain becomes affected together with the striatum's initial macroscopic alterations. Since there are presently few medications that can change the course of the disease, palliative therapy, and symptom control are the cornerstone of treatment. Studying the cellular pathology and gross structural changes to the brain which occur as the illness advances have made enormous progress in recent years. There's been a substantial increase in medical studies and possible treatment options over the past ten years. The new treatments that aim to reduce amounts of mutant huntingtin are the most optimistic. However, one strategy is antisense oligonucleotide treatment, for which clinical trials are currently being conducted. These control trials might help us get another inch ahead of managing and perhaps even eliminating this nasty disease.

Using a Clinical Formulation to Understand Psychological Distress in People Affected by Huntington’s Disease: A Descriptive, Evidence-Based Model

Huntington’s disease (HD) is an inherited, life-limiting neurodegenerative condition. People with HD experience changes in cognitive, motor and emotional functioning, and can also, mainly at later stages, exhibit behaviours that professionals and carers might find distressing such as hitting others, throwing objects, swearing or making inappropriate comments. While clinical formulation (an individualised approach used by mental health professionals to describe an individual’s difficulties) is a helpful tool to conceptualise patients’ wellbeing, a specific formulation framework has not yet been developed for HD. However, evidence has shown that formulation can help guide clinical interventions and increase consistency of approach across multi-disciplinary teams, refine risk management, and improve staff or carers’ empathic skills and understanding of complex presentations. As a consequence, this paper proposes a new clinical formulation model for understanding distress among people with HD, based on a biopsychosocial framework. More specifically, this includes key elements centring on an individual’s past experience and personal narratives, as well as anticipatory cognitions and emotions about the future. In-depth discussions regarding the components of the model and their importance in HD formulations are included, and a fictional yet representative case example is presented to illustrate their application within the context of personalised care.

Sleep Quality and Related Clinical Manifestations in Huntington Disease

(1) Background: Sleep patterns are frequently disrupted in neurodegenerative disorders such as Huntington disease (HD); however, they are still poorly understood, especially their association with clinic features. Our study aimed to explore potential correlations between sleep features and motor, cognitive, behavioural and functional changes in manifest HD subjects. (2) Methods: We enrolled 42 patients who were assessed by the Pittsburgh Sleep Quality Index (PSQI) and Insomnia Severity Index (ISI) questionnaires; clinical features were evaluated by the validated ENROLL-HD platform assay, including the Unified Huntington’s Disease Rating Scale (UHDRS) and the Problem Behaviours Assessment Short Form (PBA-s). (3) Results: We found a significant association between the patients’ perception of sleep abnormalities and scores of impaired independence, cognitive and motor performances. Specifically, sleep efficiency (PSQI—C4 subscores) and the use of sleep medications (PSQI—C6 subscores) seem to be more frequently associated with the severity of the disease progression. (4) Conclusion: sleep abnormalities represent an important part of the HD clinical profile and can impair patients’ quality of life by affecting their level of independence, cognition performance and mental well-being.

Increased Incidence of Mental Disorders in Children with Cataract: Findings from a Population-based Study

PURPOSE

To examine the incidence of mental disorders in children with cataract compared with children without cataract.

DESIGN

Nationwide cohort study based on entries in comprehensive national databases.

METHODS

The incidence of mental disorders in children born between 2000 and 2017 diagnosed with cataract before 10 years of age (n = 485) was compared with sex- and age-matched controls (n = 4358). Analyses were corrected to somatic disease in the child and parental socioeconomic status and psychiatric morbidity. The study was conducted as 2 university hospitals in Denmark managing children 6 years of age our younger with cataract.

RESULTS

The incidence of mental disorders was nearly doubled in children with cataract compared with controls (odds ratio [OR], 1.83; 95% CI, 1.28-3.63). The risk of anxiety disorders was quadrupled (OR, 4.10; 95% CI, 1.90-8.84) and the risk of developmental delay was doubled (OR, 2.66; 95% CI, 1.45-4.90). The risk of mental disorders was significantly higher in children diagnosed with cataract in the first 3 years of life compared with controls (OR, 2.36; 95% CI, 1.53-3.64), whereas those diagnosed with cataract later in childhood did not have an increased risk (OR, 1.24; 95% CI, 0.66-2.30).

CONCLUSIONS

The risk of mental disorders, in particular anxiety and neurodevelopmental delay, is markedly increased in children with cataract and even more so in those diagnosed within the first 3 years of life. Psychiatric screening instruments may be integrated in the management of these children.

Profiling Social Cognition in Premanifest Huntington's Disease

OBJECTIVE

Discrepancies exist in reports of social cognition deficits in individuals with premanifest Huntington's disease (HD); however, the reason for this variability has not been investigated. The aims of this study were to (1) evaluate group- and individual-level social cognitive performance and (2) examine intra-individual variability (dispersion) across social cognitive domains in individuals with premanifest HD.

METHOD

Theory of mind (ToM), social perception, empathy, and social connectedness were evaluated in 35 individuals with premanifest HD and 29 healthy controls. Cut-off values beneath the median and 1.5 × the interquartile range below the 25th percentile (P25 - 1.5 × IQR) of healthy controls for each variable were established for a profiling method. Dispersion between social cognitive domains was also calculated.

RESULTS

Compared to healthy controls, individuals with premanifest HD performed worse on all social cognitive domains except empathy. Application of the profiling method revealed a large proportion of people with premanifest HD fell below healthy control median values across ToM (>80%), social perception (>57%), empathy (>54%), and social behaviour (>40%), with a percentage of these individuals displaying more pronounced impairments in empathy (20%) and ToM (22%). Social cognition dispersion did not differ between groups. No significant correlations were found between social cognitive domains and mood, sleep, and neurocognitive outcomes.

CONCLUSIONS

Significant group-level social cognition deficits were observed in the premanifest HD cohort. However, our profiling method showed that only a small percentage of these individuals experienced marked difficulties in social cognition, indicating the importance of individual-level assessments, particularly regarding future personalised treatments.

Self-Reported Social Relationship Capacities Predict Motor, Functional and Cognitive Decline in Huntington’s Disease

Huntington’s Disease (HD) is an inherited neurodegenerative disease characterized by a combination of motor, cognitive, and behavioral disorders. The social and behavioral symptoms observed in HD patients impact their quality of life and probably explain their relational difficulties, conflicts, and social withdrawal. In this study, we described the development of the Social Relationship Self-Questionnaire (SRSQ), a self-reporting questionnaire that assesses how HD patients perceived their social relationships. The scale was proposed for 66 HD patients at an early stage of the disease, 32 PreHD patients (individuals carrying the mutant gene without motor symptoms), and 66 controls. The HD patients were included in a prospective longitudinal follow-up for an average of 1.07 years with motor, functional, cognitive, and behavioral assessments. Based on the HD patients’ answers at baseline, we identified two domains in the SRSQ. The first domain was related to social motivation and correlated with cognitive performance. The second domain was related to emotional insight and correlated with behavioral symptoms such as apathy, anxiety, and irritability. We discovered that both SRSQ domain scores at baseline predicted future motor, functional, and cognitive decline in HD.

Social cognition and quality of life in Huntington's disease

Individuals with Huntington's disease (HD) and their close others report difficulties with social interaction, and previous studies have shown that the areas of quality of life detrimentally impacted by HD include social and emotional domains. However, despite the finding that people with HD often exhibit difficulties on standard tests of social cognition, the relationship between such impairments and patients' everyday life has remained largely unexplored. We used a range of tasks assessing empathy, emotion recognition and Theory of Mind, to investigate whether patients' performance may predict quality of life within the social and emotional domains, while also accounting for broader cognitive function, behavioural changes, motor symptoms, disease stage and functional capacity. Poorer social functioning was predicted specifically by a reduced tendency to attribute intentionality while viewing social animations, in addition to emotional blunting and apathy, while role limitations due to emotional problems were predicted by personal distress, irritability and aspects of executive function. These findings highlight the potential impact of Theory of Mind impairment on quality of life in HD, and suggest that enhanced assessment of social cognition will offer unique insight into patients' social function and related wellbeing.

Intellectual Curiosity and Action Initiation are Subtypes of Apathy Affected in Huntington Disease Gene Expansion Carriers

BACKGROUND

Apathy is a prevalent behavioral syndrome of Huntington disease (HD) that can result in severe loss of function for the individual with HD and substantial caregiver distress. Research-based evidence of apathy is characterized by methodological differences, and there is a deficiency in the evidence concerning the subtypes of apathy.

OBJECTIVE

To characterize apathy in premanifest and motor-manifest HD gene expansion carriers and controls using the Short Problem Behaviors Assessment for Huntington's Disease (PBA-s) and the Lille Apathy Rating Scale (LARS).

METHOD

We included 82 HD gene expansion carriers (premanifest and motor manifest) and 32 controls (Mini-Mental State Examination score ≥24 and Montreal Cognitive Assessment score ≥19) in the study. We quantified apathy using the PBA-s and the LARS and performed correlation analyses between the global LARS score and motor function, cytosine-adenine-guanine repeat length, cytosine-adenine-guanine Age Product score, and neuropsychiatric and cognitive symptoms.

RESULTS

The motor-manifest HD gene expansion carriers scored significantly higher than the controls on the global score and the Intellectual Curiosity and Action Initiation subscales of the LARS. Apathy was present in 28% of the HD gene expansion carriers (including 7 premanifest). The apathetic participants had a significantly higher motor score, significantly higher scores on the neuropsychiatric instruments, and significantly lower cognitive scores compared with the controls.

CONCLUSION

Apathy is a frequent syndrome that is found in individuals with HD. Apathy has a specific expression, with symptoms such as reduced initiation, voluntary actions, and interests, that might be related to the underlying neuropathology. Apathy is related to disease progression, neuropsychiatric symptoms, and cognitive impairments.

The Impact of Anosognosia on Clinical and Patient-Reported Assessments of Psychiatric Symptoms in Huntington's Disease

BACKGROUND

Psychiatric symptoms are widely prevalent in Huntington's disease (HD) and exert greater impact on quality of life than motor manifestations. Despite this, psychiatric symptoms are frequently underrecognized and undertreated. Lack of awareness, or anosognosia, has been observed at all stages of HD and may contribute to diminished patient self-reporting of psychiatric symptoms.

OBJECTIVE

We sought to evaluate the impact of anosognosia on performance of commonly used clinical rating scales for psychiatric manifestations of HD.

METHODS

We recruited 50 HD patients to undergo a formal psychiatrist evaluation, the Problem Behavior Assessment-Short Form (PBA-s), and validated self-report rating scales for depression, anxiety, and anger. Motor impairment, cognitive function, and total functional capacity were assessed as part of clinical exam. Patient awareness of motor, cognitive, emotional, and functional capacities was quantified using the Anosognosia Rating Scale. Convergent validity, discriminant validity, classification accuracy, and anosognosia effect was determined for each psychiatric symptom rating scale.

RESULTS

Anosognosia was identified in one-third of patients, and these patients underrated the severity of depression and anxiety when completing self-report instruments. Anosognosia did not clearly influence self-reported anger, but this result may have been confounded by the sub-optimal discriminant validity of anger rating scales.

CONCLUSION

Anosognosia undermines reliability of self-reported depression and anxiety in HD. Self-report rating scales for depression and anxiety may have a role in screening, but results must be corroborated by provider and caregiver input when anosognosia is present. HD clinical trials utilizing patient-reported outcomes as study endpoints should routinely evaluate participants for anosognosia.

The experience of a sample of individuals in the United Kingdom living in the pre-manifest stage of Huntington's disease: An interpretative phenomenological analysis

This paper explores the experience of ten individuals living in the UK who were in the pre-manifest stage of Huntington's disease (HD), a genetic neurodegenerative condition. Data were gathered using semi-structured interviews and analyzed using interpretative phenomenological analysis. Three themes were reported from the data: 'feeling limited by time', 'the perception of stalling time', and 'making the most of time', all highlighting the way in which time holds significant meaning when living in the pre-manifest stage of HD. This study has highlighted the difficulties experienced by individuals when adjusting to the pre-manifest stage of HD. Feeling able to manage their anxieties and dealing with ongoing uncertainty related to future deterioration was key to supporting their wellbeing, facilitated by factors such as positivity and hope. Individuals may benefit from counseling which supports them to develop proactive coping strategies to manage their anxieties and acceptance of an uncertain future.

Cognitive and behavioral associated changes in manifest Huntington disease: A retrospective cross-sectional study

INTRODUCTION

Behavioral and cognitive changes can be observed across all Huntington disease (HD) stages. Our multicenter and retrospective study investigated the association between cognitive and behavioral scale scores in manifest HD, at three different yearly timepoints.

METHODS

We analyzed cognitive and behavioral domains by the Unified Huntington's Disease Rating Scale (UHDRS) and by the Problem Behaviors Assessment Short Form (PBA-s), at three different yearly times of life (t0 or baseline, t1 after one year, t2 after two years), in 97 patients with manifest HD (mean age 48.62 ± 13.1), from three ENROLL-HD Centers. In order to test the disease progression, we also examined patients' motor and functional changes by the UHDRS, overtime.

RESULTS

The severity of apathy and of perseveration/obsession was associated with the severity of the cognitive decline (p < .0001), regardless of the yearly timepoint. The score of irritability significantly and positively correlated with perseveration errors in the verbal fluency test at t0 (r = .34; p = .001), while the psychosis significantly and negatively correlated with the information processing speed at t0 (r = -.21; p = .038) and significantly and positively correlated with perseveration errors in the verbal fluency test at t1 (r = .35; p < .0001). The disease progression was confirmed by the significant worsening of the UHDRS-Total Motor Score (TMS) and of the UHDRS-Total Functional Capacity (TFC) scale score after two-year follow-up (p < .0001).

CONCLUSION

Although the progression of abnormal behavioral manifestations cannot be predicted in HD, the severity of apathy and perseveration/obsessions are significantly associated with the severity of the cognitive function impairment, thus contributing, together, to the disease development and to patients' loss of independence, in addition to the neurological manifestations. This cognitive-behavior pattern determines a common underlying deficit depending on a dysexecutive syndrome.

Gray Matter Vulnerabilities Predict Longitudinal Development of Apathy in Huntington's Disease

BACKGROUND

Apathy, a common neuropsychiatric disturbance in Huntington's disease (HD), is subserved by a complex neurobiological network. However, no study has yet employed a whole-brain approach to examine underlying regional vulnerabilities that may precipitate apathy changes over time.

OBJECTIVES

To identify whole-brain gray matter volume (GMV) vulnerabilities that may predict longitudinal apathy development in HD.

METHODS

Forty-five HD individuals (31 female) were scanned and evaluated for apathy and other neuropsychiatric features using the short-Problem Behavior Assessment for a maximum total of six longitudinal visits (including baseline). In order to identify regions where changes in GMV may describe changes in apathy, we performed longitudinal voxel-based morphometry (VBM) on those 33 participants with a magnetic resonance imaging (MRI) scan on their second visit at 18 ± 6 months follow-up (78 MRI datasets). We next employed a generalized linear mixed-effects model (N = 45) to elucidate whether initial and specific GMV may predict apathy development over time.

RESULTS

Utilizing longitudinal VBM, we revealed a relationship between increases in apathy and specific GMV atrophy in the right middle cingulate cortex (MCC). Furthermore, vulnerability in the right MCC volume at baseline successfully predicted the severity and progression of apathy over time.

CONCLUSIONS

This study highlights that individual differences in apathy in HD may be explained by variability in atrophy and initial vulnerabilities in the right MCC, a region implicated in action-initiation. These findings thus serve to facilitate the prediction of an apathetic profile, permitting targeted, time-sensitive interventions in neurodegenerative disease with potential implications in otherwise healthy populations. © 2021 International Parkinson and Movement Disorder Society.

Timing and Impact of Psychiatric, Cognitive, and Motor Abnormalities in Huntington Disease

Objective

To assess the prevalence, timing, and functional impact of psychiatric, cognitive, and motor abnormalities in Huntington disease (HD) gene carriers, we analyzed retrospective clinical data from individuals with manifest HD.

Methods

Clinical features of patients with HD were analyzed for 6,316 individuals in an observational study of the European Huntington's Disease Network (REGISTRY) from 161 sites across 17 countries. Data came from clinical history and the patient-completed Clinical Characteristics Questionnaire that assessed 8 symptoms: motor, cognitive, apathy, depression, perseverative/obsessive behavior, irritability, violent/aggressive behavior, and psychosis. Multiple logistic regression was used to analyze relationships between symptoms and functional outcomes.

Results

The initial manifestation of HD is increasingly likely to be motor and less likely to be psychiatric as age at presentation increases and is independent of pathogenic CAG repeat length. The Clinical Characteristics Questionnaire captures data on nonmotor symptom prevalence that correlate specifically with validated clinical measures. Psychiatric and cognitive symptoms are common in HD gene carriers, with earlier onsets associated with longer CAG repeats. Of patients with HD, 42.4% reported at least 1 psychiatric or cognitive symptom before motor symptoms, with depression most common. Each nonmotor symptom was associated with significantly reduced total functional capacity scores.

Conclusions

Psychiatric and cognitive symptoms are common and functionally debilitating in HD gene carriers. They require recognition and targeting with clinical outcome measures and treatments. However, because it is impossible to distinguish confidently between nonmotor symptoms arising from HD and primary psychiatric disorders, particularly in younger premanifest patients, nonmotor symptoms should not be used to make a clinical diagnosis of HD.

Trial Registration Information

ClinicalTrials.gov Identifier: NCT01590589

Conducting focus groups in neurodegenerative disease populations: ethical and methodological considerations

BACKGROUND

Involvement of vulnerable populations in research is critical to inform the generalisability of evidence-based medicine to all groups of the population.

OBJECTIVE

In this communication, we reflect on our previous research, and that of other authors, to identify and explore key ethical and methodological considerations.

DISCUSSION

Focus groups are a widely implemented qualitative methodology, but their use, particularly in vulnerable neurodegenerative disease populations, is not straightforward. Although the risk of harm is generally low in focus group research, neurodegenerative disease populations are particularly vulnerable to issues relating to comprehension and their capacity to consent. Physical and cognitive impairments may also affect social interactions among participants and therefore impact data collection and analyses.

CONCLUSION

We offer a number of ethical and methodological recommendations to facilitate the processes of recruitment and data collection when conducting focus groups with neurodegenerative disease populations.

Gaining insight into the views of outpatients with Huntington's disease regarding their future and the way they deal with their poor prognosis: a qualitative study

Background

Huntington’s disease (HD) has a poor prognosis. Decision-making capacity and communication ability may become lost as the disease progresses. Therefore, HD patients are encouraged to engage in advance care planning (ACP). To improve ACP for HD patients, there is a need to better understand how these patients face their poor prognosis.

Aim

To gain insight into the views of HD patients who receive outpatient care regarding their future and the way they deal with the poor prognosis of their disease.

Methods

A qualitative study using semi-structured interviews with 12 patients with HD (7 outpatient clinic, 3 day care, 2 assisted living facility). Audio-recorded interviews were transcribed verbatim. Through reading and re-reading interviews, writing memos and discussions in the research team, strategies were identified.

Results

Three strategies emerged for facing a future with HD. Participants saw the future: 1) as a period that you have to prepare for; 2) as a period that you would rather not think about; 3) as a period that you do not have to worry about yet. Participants could adopt more than one strategy at a time. Even though participants realized that they would deteriorate and would need more care in the future, they tried to keep this knowledge ‘at a distance’, with the motivation of keeping daily life as manageable as possible.

Conclusions

Official ACP guidelines recommend discussing goals and preferences for future treatment and care, but patients tend to want to live in the present. Further research is needed to elucidate the best approach to deal with this discrepancy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12904-020-00706-x.

Risk-Taking Behaviors in Huntington's Disease

BACKGROUND

Risky behaviors are common in Huntington's disease (HD) and can lead to significant adverse consequences. However, the prevalence and scope of these symptoms have not been studied systematically, and no empirically validated measures are available to screen for them.

OBJECTIVE

To test a novel screening tool designed to assess risk-taking behaviors in HD.

METHODS

We administered the Risk Behavior Questionnaire (RBQ-HD) to HD patients and caregivers at Vanderbilt University Medical Center between 2018-2019. Patients completed the questionnaire based on self-report; caregivers provided collateral reports. Clinical and demographic information were obtained from the electronic medical record.

RESULTS

60 patients and 60 caregivers completed the RBQ-HD. 80% of patients (n = 48) and 91.7% of caregivers (n = 60) reported at least one risky behavior. Adverse social behaviors, impulsive/compulsive behaviors, and reckless driving were the most common behavioral domains reported. Male patients were more likely to report risky behaviors than females (92.3% vs. 70.6%, p = 0.04). The number of risky behaviors reported by patients and caregivers was negatively correlated with patient age (r = -0.32, p = 0.01; r = -0.47, p = 0.0001, respectively). Patient and caregiver reports were highly correlated in matched pairs (n = 30; r = 0.63, p = 0.0002).

CONCLUSION

These findings emphasize that risky behaviors are highly prevalent in HD and can be effectively identified through the use of a novel screening measure. We hypothesize that early pathological involvement of frontostriatal and mesolimbic networks may be important factors in the development of these behaviors.

Cognitive and behavioural inhibition deficits in neurodegenerative dementias

Disinhibition, mainly caused by damage in frontotemporal brain regions, is one of the major causes of caregiver distress in neurodegenerative dementias. Behavioural inhibition deficits are usually described as a loss of social conduct and impulsivity, whereas cognitive inhibition deficits refer to impairments in the suppression of prepotent verbal responses and resistance to distractor interference. In this review, we aim to discuss inhibition deficits in neurodegenerative dementias through behavioural, cognitive, neuroanatomical and neurophysiological exploration. We also discuss impulsivity and compulsivity behaviours as related to disinhibition. We will therefore describe different tests available to assess both behavioural and cognitive disinhibition and summarise different manifestations of disinhibition across several neurodegenerative diseases (behavioural variant of frontotemporal dementia, Alzheimer's disease, Parkinson's disease, progressive supranuclear palsy, Huntington's disease). Finally, we will present the latest findings about structural, metabolic, functional, neurophysiological and also neuropathological correlates of inhibition impairments. We will briefly conclude by mentioning some of the latest pharmacological and non pharmacological treatment options available for disinhibition. Within this framework, we aim to highlight i) the current interests and limits of tests and questionnaires available to assess behavioural and cognitive inhibition in clinical practice and in clinical research; ii) the interpretation of impulsivity and compulsivity within the spectrum of inhibition deficits; and iii) the brain regions and networks involved in such behaviours.

Imbalance of the oxytocin-vasopressin system contributes to the neuropsychiatric phenotype in the BACHD mouse model of Huntington disease

Neuropsychiatric disturbances with altered social cognition, depression and anxiety are among the most debilitating early features in the fatal neurodegenerative disorder Huntington disease (HD) which is caused by an expanded CAG repeat in the huntingtin gene. The underlying neurobiological mechanisms are not known. Neuropathological analyses of postmortem human HD hypothalamic tissue have demonstrated loss of the neuropeptides oxytocin and vasopressin. The dynamic interplay between these neuropeptides is crucial for modulating emotional and social behavior but its role in HD is unclear. In the present study, we have investigated the effect of expressing the mutant huntingtin gene on the development of behavioral changes using the transgenic BACHD mouse model at different ages. We show for the first time that BACHD mice exhibit deficits in social behavior with parallel aberrations in the balance of the oxytocin-vasopressin system. Importantly, our data also show that restoration of the interplay within the system with an acute dose of intranasal oxytocin immediately prior to behavioral testing can rescue the depressive-like phenotype but not anxiety-like behavior in this transgenic model. These findings demonstrate that imbalances in the oxytocin-vasopressin interplay contribute to the neuropsychiatric component of HD and suggest that interventions aimed at restoring the blunted levels of oxytocin may confer therapeutic benefits for this disease.

The effects of multidisciplinary rehabilitation on neuroimaging, biological, cognitive and motor outcomes in individuals with premanifest Huntington's disease

BACKGROUND

Huntington's disease (HD) is a chronic, progressive neurodegenerative condition for which there are currently no proven disease-modifying therapies. Lifestyle factors have been shown to impact on the age of disease onset and progression of disease features. We therefore investigated the effects of a nine-month multidisciplinary rehabilitation intervention on neuroimaging, biological and clinical disease outcomes in individuals with premanifest HD.

METHODS

31 individuals with premanifest HD participated in the study. Eighteen participants underwent a nine-month multidisciplinary rehabilitation intervention comprising aerobic and resistance exercise, computerised cognitive training, dual-task training and sleep hygiene and nutritional guidance. The remaining 13 participants were allocated to a standard care control group. Neuroimaging, biological, cognitive, motor and cardiorespiratory fitness data was collected.

RESULTS

Participants displayed good adherence (87%) and compliance (85%) to the intervention. Maintenance of the shape of the right putamen was observed in the intervention group when compared to the control group. The intervention group displayed significant improvements in verbal learning and memory, attention, cognitive flexibility and processing speed following the intervention when compared to the control group. Performance on the mini-social cognition and emotional assessment (mini-SEA) was maintained in the intervention group, but decreased in the control group. No changes were observed in serum neurofilament light protein levels, postural stability outcomes or cardiorespiratory fitness.

CONCLUSION

This study adds to the accumulating body of literature to suggest that multidisciplinary rehabilitation is of clinical benefit for individuals with HD. Large randomised controlled trials are necessary to determine the extent to which benefits occur across the spectrum of the disease.

Why Woody got the blues: The neurobiology of depression in Huntington's disease

Huntington's disease (HD) is an extraordinary disorder that usually strikes when individuals are in the prime of their lives, as was the case for the influential 20th century musician Woody Guthrie. HD demonstrates the exceptionally fine line between life and death in such 'genetic diseases', as the only difference between those who suffer horribly and die slowly of this disease is often just a handful of extra tandem repeats (beyond the normal polymorphic range) in a genome that constitutes over 3 billion paired nucleotides of DNA. Furthermore, HD presents as a complex and heterogenous combination of psychiatric, cognitive and motor symptoms, so can appear as an unholy trinity of 'three disorders in one'. The autosomal dominant nature of the disorder is also extremely challenging for affected families, as a 'flip of a coin' dictates which children inherit the mutation from their affected parent, and the gene-negative family members bear the burden of caring for the other half of the family that is affected. In this review, we will focus on one of the earliest, and most devastating, symptoms associated with HD, depression, which has been reported to affect approximately half of gene-positive HD family members. We will discuss the pathogenesis of HD, and depressive symptoms in particular, including molecular and cellular mechanisms, and potential genetic and environmental modifiers. This expanding understanding of HD pathogenesis may not only lead to novel therapeutic options for HD families, but may also provide insights into depression in the wider population, which has the greatest burden of disease of any disorder and an enormous unmet need for new therapies.

Genetic Risk Underlying Psychiatric and Cognitive Symptoms in Huntington's Disease

BACKGROUND

Huntington's disease (HD) is an inherited neurodegenerative disorder caused by an expanded CAG repeat in the HTT gene. It is diagnosed following a standardized examination of motor control and often presents with cognitive decline and psychiatric symptoms. Recent studies have detected genetic loci modifying the age at onset of motor symptoms in HD, but genetic factors influencing cognitive and psychiatric presentations are unknown.

METHODS

We tested the hypothesis that psychiatric and cognitive symptoms in HD are influenced by the same common genetic variation as in the general population by 1) constructing polygenic risk scores from large genome-wide association studies of psychiatric and neurodegenerative disorders and of intelligence and 2) testing for correlation with the presence of psychiatric and cognitive symptoms in a large sample (n = 5160) of patients with HD.

RESULTS

Polygenic risk score for major depression was associated specifically with increased risk of depression in HD, as was schizophrenia risk score with psychosis and irritability. Cognitive impairment and apathy were associated with reduced polygenic risk score for intelligence.

CONCLUSIONS

Polygenic risk scores for psychiatric disorders, particularly depression and schizophrenia, are associated with increased risk of the corresponding psychiatric symptoms in HD, suggesting a common genetic liability. However, the genetic liability to cognitive impairment and apathy appears to be distinct from other psychiatric symptoms in HD. No associations were observed between HD symptoms and risk scores for other neurodegenerative disorders. These data provide a rationale for treatments effective in depression and schizophrenia to be used to treat depression and psychotic symptoms in HD.

Medical, Surgical, and Genetic Treatment of Huntington Disease

Huntington disease, a neurodegenerative disease characterized by progressive motor, behavioral, and cognitive decline, is caused by a CAG trinucleotide repeat expansion in the huntingtin gene on chromosome 4. Current treatments target symptom management because there are no disease-modifying therapies at this time. Investigation of RNA-based and DNA-based treatment strategies are emerging and hold promise of possible future disease-modifying therapy.

Longitudinal study revealing motor, cognitive and behavioral decline in a transgenic minipig model of Huntington's disease

Huntington's disease (HD) is an inherited devastating neurodegenerative disease with no known cure to date. Several therapeutic treatments for HD are in development, but their safety, tolerability and efficacy need to be tested before translation to bedside. The monogenetic nature of this disorder has enabled the generation of transgenic animal models carrying a mutant huntingtin (mHTT) gene causing HD. A large animal model reflecting disease progression in humans would be beneficial for testing the potential therapeutic approaches. Progression of the motor, cognitive and behavioral phenotype was monitored in transgenic Huntington's disease minipigs (TgHD) expressing the N-terminal part of human mHTT. New tests were established to investigate physical activity by telemetry, and to explore the stress-induced behavioral and cognitive changes in minipigs. The longitudinal study revealed significant differences between 6- to 8-year-old TgHD animals and their wild-type (WT) controls in a majority of the tests. The telemetric study showed increased physical activity of 4.6- to 6.5-year-old TgHD boars compared to their WT counterparts during the lunch period as well as in the afternoon. Our phenotypic study indicates progression in adult TgHD minipigs and therefore this model could be suitable for longstanding preclinical studies of HD.

This article has an associated First Person interview with the first author of the paper.

Summary: The transgenic minipig model of Huntington's disease demonstrates a slow-progressing motor, cognitive and behavioral phenotype with later onset in adulthood.

Discrete changes in the frequency and functions of autobiographical reminiscence in Huntington's disease

Autobiographical memory is widely posited to serve self, social and directive functions. Recent evidence suggests marked autobiographical memory impairments in Huntington's disease (HD), however, no study to date has determined how the perceived functions of autobiographical reminiscence may be altered in HD. The current study aimed to assess the self-reported frequency and function of autobiographical reminiscence in HD. We assessed autobiographical reminiscence in late premanifest (n = 16) and early stage HD (n = 14), relative to healthy controls (n = 30). Participants completed the Thinking About Life Experiences Scale Revised (TALE-R), which measures three putative functions of autobiographical memory (self, social, directive). People with manifest HD reported talking less frequently about the past compared to controls. In contrast, no group differences were found in terms of thinking about the past. Manifest HD participants further reported using their autobiographical memories for social functions less frequently compared to controls. No other group differences were evident in terms of self or directive functions of autobiographical memory. These self-report findings complement recent reports of autobiographical memory disruption on performance-based tasks in HD. Future studies exploring how changes in autobiographical reminiscence impact a sense of self continuity in HD will be important in this regard.

Exploring the Reliability and Validity of the Huntington's Disease Quality of Life Battery for Carers (HDQoL-C) within A Polish Population

Huntington’s disease (HD) is a rare genetic neurodegenerative disorder that causes motor disorders, neuropsychiatric symptoms and a progressing deterioration of cognitive functions. Complex issues resulting from the hereditary nature of HD, the complexity of symptoms and the concealed onset of the disease have a great impact on the quality of life of family carers. The caregivers are called the “forgotten people” in HD, especially with relation to genetic counseling. This study aims to explore the reliability and validity of the Huntington’s Disease Quality of Life Battery for carers (HDQoL-C) within a Polish population. A total of 90 carers recruited from the Enroll-HD study in Polish research centers of the European Huntington’s Disease Network completed a polish translation of the HDQoL-C. Data were subjected to Principle Components Analysis (PCA) and reliability measures. The Polish version of the shortened versions of the HDQoL-C is similarly valid compared to the original English version and suitable for use within this population. The HDQoL-C has previously demonstrated a wide range of benefits for practitioners in capturing and understanding carer experience and these benefits can now be extended to Polish speaking populations.

Huntington's Disease Outpatient Clinic for Functional Diagnosis and Treatment: Coming to Consensus: How Long Term Care Facility Procedures Complement Specialist Diagnosis and Treatment

Huntington’s disease (HD) patients and families deserve expert treatment and care throughout their lives, but uniformity in functional diagnosis and treatment was lacking. In the aim of reaching this uniformity on day-to-day treatment and care offered by multidisciplinary outreach teams from Dutch long term care facilities for ambulatory HD patients, a consensus trajectory was started to harmonise our care programme with international standards and within the country. The consensus statements, given as supplementary material, should lead to expert treatment and care for HD families throughout the Netherlands and this manuscript should contribute and revitalise a global discussion on standards of treatment and care.

Clinical Neurology and Epidemiology of the Major Neurodegenerative Diseases

Neurodegenerative diseases are a common cause of morbidity and cognitive impairment in older adults. Most clinicians who care for the elderly are not trained to diagnose these conditions, perhaps other than typical Alzheimer's disease (AD). Each of these disorders has varied epidemiology, clinical symptomatology, laboratory and neuroimaging features, neuropathology, and management. Thus, it is important that clinicians be able to differentiate and diagnose these conditions accurately. This review summarizes and highlights clinical aspects of several of the most commonly encountered neurodegenerative diseases, including AD, frontotemporal dementia (FTD) and its variants, progressive supranuclear palsy (PSP), corticobasal degeneration (CBD), Parkinson's disease (PD), dementia with Lewy bodies (DLB), multiple system atrophy (MSA), and Huntington's disease (HD). For each condition, we provide a brief overview of the epidemiology, defining clinical symptoms and diagnostic criteria, relevant imaging and laboratory features, genetics, pathology, treatments, and differential diagnosis.