Survival, Mortality, Causes and Places of Death in a European Huntington's Disease Prospective Cohort

The impact of expiratory muscle strength training on voluntary cough effectiveness in Huntington's disease

BACKGROUND AND PURPOSE

Dysfunction of the airway defence system in Huntington's disease (HD) is a significant but often overlooked problem. Although expiratory muscle strength training (EMST) is frequently utilized in cough effectiveness treatment, its specific impact in HD patients has not yet been explored. This study investigated the effects of EMST on voluntary peak cough flow (vPCF) in HD patients and evaluated the retention of potential gains post-intervention.

METHODS

In this prospective case-controlled trial, 29 HD patients completed an 8-week wait-to-start period, which served to identify the natural development of expiratory muscle strength and vPCF. This was followed by 8 weeks of EMST training and an additional 8 weeks of follow-up. The study's outcome parameters, vPCF and maximum expiratory pressure (MEP), were measured against those of age- and sex-matched healthy controls.

RESULTS

Huntington's disease patients had significantly lower MEP (p < 0.001) and vPCF (p = 0.012) compared to healthy controls at baseline. Following the EMST, significant improvements in MEP (d = 1.39, p < 0.001) and vPCF (d = 0.77, p = 0.001) were observed, with HD patients reaching the cough performance levels of healthy subjects. However, these gains diminished during the follow-up, with a significant decline in vPCF (d = -0.451, p = 0.03) and in MEP (d = -0.71; p = 0.002).

CONCLUSIONS

Expiratory muscle strength training improves expiratory muscle strength and voluntary cough effectiveness in HD patients, but an ongoing maintenance programme is necessary to sustain the improvements.

Development of a General Composite Scale (GENCOMS) for Progressive Neurodegenerative Diseases and Implications for the Assessment of Disease-Modifying Therapies

INTRODUCTION

The reliable assessment of treatment outcomes for disease-modifying therapies (DMT) in neurodegenerative disease is challenging. The objective of this paper is to describe a generalized framework for developing composite scales that can be applied in diverse, degenerative conditions, termed "GENCOMS." Composite scales optimize the sensitivity for detecting clinically meaningful effects that slow disease progression.

METHODS

The GENCOMS method relies on robust natural history data and/or placebo arm data from DMT trials. Validated scales that are core to the disease process have been identified, and item level data obtained to standardize the response outcomes from 0 (best possible score) to 1 (worst possible score). A partial least squares regression analysis was conducted with temporal change as the dependent variable and change scores in standardized items as the explanatory variables. The derived model coefficients constitute a weighted sum of items that most effectively measure disease progression.

RESULTS

The resultant composite scale was optimized to detect disease progression and can be examined in a range of slow or fast progressing populations. The scale can be used in studies with comparable patient populations as an endpoint optimized to measure disease progression and therefore ideally suited to assess treatment effects in DMTs.

CONCLUSION

The methodology presented here provides a generalizable framework for developing composite scales in the assessment of neurodegenerative disease progression and evaluation of DMT effects. By objectively selecting and weighting items from previously validated measures based solely on their sensitivity to disease progression, this methodology allows for the creation of a more responsive measurement of clinical decline. This heightened sensitivity to clinical decline can be utilized to detect modest yet meaningful treatment effects in the early stages of neurogenerative diseases, when it is optimal to begin a DMT.

Outcomes of Percutaneous Endoscopic Gastrostomy in Huntington's Disease at a Tertiary Center

BACKGROUND

Clinically assisted nutrition and hydration via percutaneous endoscopic gastrostomy (PEG) is a therapeutic option to ameliorate the difficulties associated with enhanced catabolism, weight loss, and dysphagia in Huntington's disease (HD).

OBJECTIVES

The objective is to provide insights into demographics, staging (Shoulson-Fahn), complications, weight trajectories, and survival rates in people with HD (pwHD) who underwent PEG.

METHODS

This retrospective study included 705 consecutive pwHD who attended our HD clinic between July 2006 and March 2024, of whom 52 underwent PEG. A control group (n = 52), comprising pwHD without PEG, were closely matched for sex, stage, age, CAG length, and disease burden score at PEG. The study was registered as a service evaluation at the National Hospital for Neurology and Neurosurgery.

RESULTS

PEG prevalence was 15.0% (n = 52/347) among manifest pwHD: 4.8% (n = 3/62) for Stage 3; 33.3% (n = 16/48) for stage 4; and 44.1% (n = 30/68) for stage 5. Commonest indications were dysphagia, weight loss, and inadequate oral intake. Complications included chest infection, tube dislodgement, and peristomal and skin infections. Modeling of weight trajectories after PEG found no difference between PEG and non-PEG groups. Mortality rate was 34.6% (n = 18/52) in the PEG and 36.5% (n = 19/52) in the non-PEG groups (P = 0.84). Treatment duration (until study endpoint or death) was 3.48 years (interquartile range = 1.71-6.02; range = 0.23-18.8), with 65.4% (n = 34/52) alive at the study endpoint.

CONCLUSION

PEG in pwHD at-risk for weight loss may help slow weight loss. Prospective studies are required to strengthen PEG decision-making in pwHD. PEG survival was much longer than other dementias, highlighting the need to consider PEG independently in pwHD.

Risk Factors and Interventions for Suicide in Huntington's Disease-A Systematic Review

Background/Objectives: Huntington's disease (HD) is an autosomal dominant genetic disorder causing progressive neurodegeneration which, aside from symptomatic therapies for controlling psychological and motor problems, currently has no effective treatment. People who receive this diagnosis often feel disoriented and lost without guidance. Furthermore, HD patients are estimated to have a two to seven times greater risk of suicide death compared to the general population. The current review investigates the complex relationship between HD and suicide, seeking to identify key risk factors influencing suicidal ideation and behaviour in affected individuals. Methods: We conducted a systematic review following the PRISMA guidelines. Studies were searched for on the PubMed, Cochrane, and Web of Science databases, and 17 articles met the inclusion criteria. Results: The findings reveal that emotional strain, neuropsychiatric symptoms, and the absence of a cure contribute to heightened suicidal tendencies in HD patients. Critical periods for suicide risk coincide with early symptomatic stages of disease or the successive phase, with the loss of independence impacting on daily functioning. Risk factors associated with HD include a depressive mood, cognitive impairments, and a history of suicide attempts. Conclusions: From a prevention perspective, a comprehensive multidisciplinary and multidimensional approach could enhance the overall well-being of people with HD. In particular, screening for suicidal thoughts in people with HD could mitigate suicide risk.

Experiences of young people growing up in a family with Huntington's disease: A meta-ethnography of qualitative research

Huntington's disease is a genetic neurodegenerative condition with wide physical and psychological impacts. Children of a parent with the condition have a 50% chance of carrying the gene expansion and developing the condition themselves. This systematic review and meta-ethnography presents a synthesis of the qualitative research on the experiences of young people growing up in a family with Huntington's disease. The MEDLINE, PsycINFO, and CINAHL databases were systematically searched, and 13 papers met the inclusion criteria. Through the process of meta-ethnography, four themes were identified highlighting aspects of childhood that were stolen and fought for: thief of relationships, thief of self, thief of transparency, and search for reclamation. Within the themes, the complex challenges young people faced when growing up in a HD family were explored such as the impact of adverse childhood experiences and the possible effects of HD on attachment and social relationships. Clinical implications are considered, and recommendations are made for future research.

Huntington's Disease-Related Mortality Patterns: A Two-Decade Analysis of Mortality Trends in the United States, from 1999-2019

Background

Huntington's disease (HD) is an autosomal dominant, progressive neurodegenerative disorder debilitating mainly in adults.

Objective

This study aimed to assess the trends in HD-related mortality regarding various demographic factors.

Methods

Death certificates from the CDC WONDER were studied from 1999 to 2019, for HD-related mortality in adults aged 25 + years. Age-adjusted Mortality Rate (AAMR) per 100,000 persons and Annual Percentage Change (APC) were calculated and stratified by year, age groups, gender, race/ethnicity, state, census region, urbanization, and place of death.

Results

Between 1999 to 2019, 22,595 deaths occurred in adults due to HD. The AAMR increased from 0.43 to 0.54 during this period (APC = 0.50; 95% CI: 0.18 to 0.84). Old adults (65-85 + years) had the highest overall AAMR, followed by middle-aged adults (45-64 years) and young adults (25-44 years) (AAMR old: 1.01 vs. AAMR middle-age: 0.68 vs. AAMR young: 0.16). Men had slightly greater overall AAMRs than women (AAMR men: 0.54 vs. AAMR women: 0.48). When stratified by race, non-Hispanic (NH) Whites had significantly higher mortality rates than NH African Americans (AAMR NH White: 0.61 vs. NH African American: 0.35), while the AAMR were lowest in Hispanic/Latino (0.28). The AAMRs also showed variation by region (overall AAMR: Midwest: 0.63, Northeast: 0.47, West: 0.48, South: 0.46), and non-metropolitan areas had higher HD-related AAMR (0.66) than metropolitan areas (0.47).

Conclusions

HD-related mortality in US adults has increased since 1999. Reflecting on the variations in trends observed, new strategies are required to optimize the quality of care in long-term care facilities.

DSM-5-TR diagnosis as a guide to suicide risk assessment

A specific mental disorder can itself constitute a risk factor for a completed suicide. Even more important, the disorder is typically a modifiable risk factor which informs its own treatment. Recent editions of the DSM have included "suicide subsections" for specific mental disorders and conditions in which the risks of suicidal thoughts and behaviors for the disorder are noted in the literature. The DSM-5-TR can therefore serve as a compendium to be referred to for initial guidance as to whether a specific disorder could contribute to the risk. Adding completed suicides and suicide attempts, also addressed in these subsections, the sections were examined individually for the four parameters of suicidality. Accordingly, the four parameters of suicidality examined here are: suicide, suicidal thoughts, suicidal behavior, and suicide attempts. After providing interpretive comments for each, the parameters for all disorders with a suicide subsection were tabulated for ease of reference. Because specific medical disorders are also associated with elevated rates of suicide, these disorders and the supporting research are tabulated and briefly acknowledged. Allowing for the limitations of the suicide subsections and their analysis, this exegesis is proposed to contribute to training in risk assessment for forensic psychiatry and psychology fellows and to highlight the potential referential value of the DSM-5-TR's suicide subsections for clinical practitioners and those who pursue research on suicide.

Factors Associated With the Place of Death in Huntington Disease: Analysis of Enroll-HD

Background: Most people prefer to die at home. Hospice is the standard in end-of-life care for people with Huntington disease (HD), a neurodegenerative genetic disorder that affects people in middle adulthood. Yet, we have little knowledge regarding the place of death for people with HD. Therefore, the current state of knowledge limits HD clinicians' ability to conduct high-quality goals of care conversations. Objectives: We sought to determine the factors associated with the place of death in people with HD. Design: We obtained cross-sectional data from Enroll-HD and included participants with a positive HD mutation of 36 or more CAG repeats. Results: Out of 16,120 participants in the Enroll-HD study, 536 were reported as deceased. The mean age at death was 60. The leading place of death was home (29%), followed by the hospital (23%). The adjusted odds ratio (aOR) of dying at a skilled nursing facility was significantly lower for those partnered (aOR: 0.48, confidence interval [95% CI]: 0.26-0.86). The aOR for dying on hospice compared to home was increased in a person with some college and above (aOR: 2.40, 95% CI: 1.21-4.75). Conclusions: Our data further suggest that models that predict the place of death for serious illnesses do not appear to generalize to HD. The distribution in the places of death within HD was not uniform. Our findings may assist HD clinicians in communication during goals of care conversations.

Novel EAAT2 activators improve motor and cognitive impairment in a transgenic model of Huntington's disease

Introduction

Glutamate excitotoxicity is causal in striatal neurodegeneration underlying motor dysfunction and cognitive deficits in Huntington's disease (HD). Excitatory amino acid transporter 2 (EAAT2), the predominant glutamate transporter accounting for >90% of glutamate transport, plays a key role in preventing excitotoxicity by clearing excess glutamate from the intrasynaptic cleft. Accordingly, EAAT2 has emerged as a promising therapeutic target for prevention of neuronal excitotoxicity underlying HD and other neurodegenerative diseases.

Methods

We have previously designed novel EAAT2 positive allosteric modulator GT951, GTS467, and GTS551, with low nanomolar efficacy in glutamate uptake and favorable pharmacokinetic properties. In this study, we test the neuroprotective abilities of these novel EAAT2 activators in vivo using the robust Drosophila HD transgenic model expressing human huntingtin gene with expanded repeats (Htt128Q).

Results

All three compounds significantly restored motor function impaired under HD pathology over a wide dose range. Additionally, treatment with all three compounds significantly improved HD-associated olfactory associative learning and short-term memory defects, while GT951 and GTS551 also improved middle-term memory in low-performing group. Similarly, treatment with GT951 and GTS551 partially protected against early mortality observed in our HD model. Further, treatment with all three EAAT2 activators induced epigenetic expression of EAAT2 Drosophila homolog and several cognition-associated genes.

Conclusion

Together, these results highlight the efficacy of GT951, GTS467 and GTS551 in treating motor and cognitive impairments under HD pathology and support their development for treatment of HD.

[Huntington disease in the Valencian Region]

INTRODUCTION

Huntington disease (HD) is a rare neurodegenerative disorder of the central nervous system characterized by unwanted choreatic movements, behavioral and psychiatric disturbances and dementia.

OBJECTIVE

Describe the geographical, age and sex distribution of HD in the Valencia Region (VR) and determine its prevalence and mortality.

MATERIALS AND METHODS

Cross-sectional study for the period 2010-2018. Confirmed cases of HD were identified through the Rare Disease Information System of the VR. Sociodemographic characteristics were described, and the prevalence and mortality rate were obtained.

RESULTS

225 cases were identified, 50.2% women. 52.0% lived in the province of Alicante. 68.9% were verified by their clinical diagnosis. The median age at diagnosis was 54.1 years, 54.7 years in men and 53.0 years in women. The prevalence in 2018 was 1.97/100,000 inhabitants (95%; CI: 0.39-2.37), showing a no significant increasing trend, overall and by sex. 49.8% died, 51.8% men. The median age at death was 62.7 years, being lower in men than in women. The mortality rate in 2018 was 0.32/100,000 inhabitants (95%; CI: 0.32-2.28), with no statistically significant differences.

CONCLUSIONS

The prevalence obtained was within the range estimated by Orphanet (1-9/100,000). A difference between sexes was observed in the diagnosis age. Men are the group with the highest mortality and the earliest age of death. It is a disease with high mortality with an average of 6.5 years between diagnosis and death.

Survival in Huntington's disease and other young-onset dementias

OBJECTIVES

To compare survival and risk factors associated with mortality in common young-onset dementias (YOD) including Huntington's disease.

METHODS

This retrospective cohort study included inpatients from an Australian specialist neuropsychiatry service, over 20 years. Dementia diagnoses were based on consensus criteria and Huntington's disease (HD) was confirmed genetically. Mortality and cause of death were determined using linkage to the Australian Institute of Health and Welfare National Death Index.

RESULTS

There were 386 individuals with YOD included. The dementia types included frontotemporal dementia (FTD) (24.5%), HD (21.2%) and Alzheimer's disease (AD) (20.5%). 63% (n = 243) individuals had died. The longest median survival was for those who had HD, 18.8 years from symptom onset and with a reduced mortality risk compared to AD and FTD (hazard ratio 0.5). Overall, people with YOD had significantly increased mortality, of 5-8 times, compared to the general population. Females with a YOD had higher standardised mortality ratio compared to males (9.3 vs. 4.9) overall. The most frequent cause of death in those with HD was reported as HD, with other causes of death in the other YOD-subtypes related to dementia and mental/behavioural disorders.

DISCUSSION

This is the first Australian study to investigate survival and risk factors of mortality in people with YOD. YOD has a significant risk of death compared to the general population. Our findings provide useful clinical information for people affected by YOD as well as future planning and service provision.

Diagnostic Uncertainties: Chorea

Chorea is a hyperkinetic movement disorder with a multitude of potential etiologies, both acquired and inherited. Although the differential diagnosis for new-onset chorea is extensive, there are often clues in the history, exam, and basic testing that can help to narrow the options. Evaluation for treatable or reversible causes should take priority, as rapid diagnosis can lead to more favorable outcomes. While Huntington's disease is most common genetic cause of chorea, multiple phenocopies also exist and should be considered if Huntington gene testing is negative. The decision of what additional genetic testing to pursue should be based on both clinical and epidemiological factors. The following review provides an overview of the many possible etiologies as well as a practical approach for a patient presenting with new-onset chorea.

Comorbidities and clinical outcomes in adult- and juvenile-onset Huntington's disease: a study of linked Swedish National Registries (2002-2019)

BACKGROUND

Huntington's disease (HD) is a rare, neurodegenerative disease and its complex motor, cognitive and psychiatric symptoms exert a lifelong clinical burden on both patients and their families.

OBJECTIVE

To describe the clinical burden and natural history of HD.

METHODS

This longitudinal cohort study used data from the linked Swedish national registries to describe the occurrence of comorbidities (acute and chronic), symptomatic treatments and mortality in an incident cohort of individuals who either received the first diagnosis of HD above (adult onset HD; AoHD) or below (juvenile-onset HD; JoHD) 20 years of age, compared with a matched cohort without HD from the general population. Disease burden of all individuals alive in Sweden was described during a single calendar year (2018), including the occurrence of key symptoms, treatments and hospitalizations.

RESULTS

The prevalence of HD in 2018 was approximately 10.2 per 100,000. Of 1492 individuals with a diagnosis of HD during 2002 and 2018, 1447 had AoHD and 45 had JoHD. Individuals with AoHD suffered a higher incidence of obsessive-compulsive disorder, acute psychotic episodes, pneumonia, constipation and fractures compared with matched controls. Individuals with JoHD had higher incidence rates of epilepsy, constipation and acute respiratory symptoms. Median time to all-cause mortality in AoHD was 12.1 years from diagnosis. Patients alive with HD in Sweden in 2018 displayed a pattern of increased clinical burden for a number of years since diagnosis.

CONCLUSIONS

This study demonstrates the significant and progressive clinical burden in individuals with HD and presents novel insights into the natural history of JoHD.

Layers of Loss: A Scoping Review and Taxonomy of HD Caregivers' Spiritual Suffering, Grief/Loss and Coping Strategies

CONTEXT

Huntington's disease (HD), an incurable, multi-generational, autosomal dominant disorder, creating unique challenges and a myriad of spiritually-related stressors in those affected and their familial caregivers. Spiritual suffering, experiences of grief/loss, and coping strategies have not been systematically studied in HD caregivers.

OBJECTIVES

To comprehensively define spiritual suffering, grief/loss, and coping strategies used by HD caregivers.

METHODS

A PRISMA-ScR scoping literature review was conducted. Data from included research articles were organized thematically using induction and open coding. A grounded, deductive approach was used to delineate a demarcated taxonomy of themes, which encompasses all three over-arching domains. Four reviewers, employing a modified Delphi approach, ascertained which themes were demonstrated by research participants in each study.

RESULTS

36 of 583 articles met the review criteria; none were published in the palliative care literature. Investigations primarily focused on intrapersonal (self-image) distress and existential angst; only rarely looking deeper into divine/transpersonal suffering, disrupted religious relationships, or meaning distress. HD caregivers experience profound grief/loss, expressed as disenfranchised grief that is associated with the ambiguous loss of their loved one, loss of family structure, social connectedness, and personal losses. Half of the studies reported maladaptive HD caregiver coping strategies-characterized by dysfunctional escape schemes; in contrast, transcendent/creative strategies were often unexplored.

CONCLUSION

HD caregivers experience prolonged grief and other forms of spiritual suffering as they progressively lose their loved ones and disruption to their own lives. With an improved assessment tool, teams with spiritual and palliative care experts will better be able to support HD family caregivers.

Huntington's disease: Mortality and risk factors in an Australian cohort

INTRODUCTION

There has not been any examination of the risk factors associated with mortality in Huntington's Disease (HD) in an Australian cohort.

METHOD

This retrospective study included inpatients admitted to a specialist neuropsychiatry service in Melbourne, Australia. HD status was based on genetic testing. Risk factors included age of onset, CAG repeat length and neuroimaging. Mortality data was acquired through the Australian Institute of Health and Welfare National Death Index.

RESULTS

The cohort included 83 participants, with 44 (53%) deceased. The median age of death was 59 years and median survival was 18.8 years from onset age (median 41.0 years). CAG repeat length (median 44.0, IQR 42.5, 47.0) was inversely correlated with age of onset (r = -0.73) and age at death (r = -0.80) but was not correlated with mortality status. There was no difference in functional and cognitive assessments, nor brain volumes, in the alive group compared to the deceased group. There were more people who were alive who had a positive family history of a psychiatric condition (p = 0.006) or dementia (p = 0.009). Standardised mortality ratios demonstrated a 5.9× increased risk of death for those with HD compared to the general population.

CONCLUSIONS

This is the first study to examine risk factors of mortality in HD in an Australian cohort. Median survival in our cohort is consistent with previous studies in HD, and markedly reduced compared to the general Australian population. CAG repeat length was not associated with mortality suggesting that non-genetic factors contribute to mortality status and warrant further investigation.

Home-Based Exercise to Improve Motor Functions, Cognitive Functions, and Quality of Life in People with Huntington's Disease: A Systematic Review and Meta-Analysis

Exercise in different settings has become a fundamental part of Huntington's disease (HD) management. The aim of this systematic review and meta-analysis was to investigate the effectiveness of home-based exercises (HBE) in HD. Randomized controlled trials (RCTs) investigating the effect of HBE on motor, cognitive, or health-related quality of life (QoL) outcomes in HD were included. Standardized mean difference (SMD), the 95% confidence interval, and p-values were calculated by comparing the outcomes change between HBE and control groups. Seven RCTs met the inclusion criteria. The included RCTs prescribed different types of HBEs, i.e., aerobic strengthening, walking, balance, and fine motor exercises. The HBE protocol length was between 6 and 36 weeks. The meta-analyses showed a significant effect of HBE intervention on motor function measure by Unified Huntington Disease Rating and overall QoL measure by Short Form-36 post-treatment respectively, [SMD = 0.481, p = 0.048], [SMD = 0.378, p = 0.003]. The pooled analysis did not detect significant changes in cognition, gait characteristics, or functional balance scales. The current study shows the positive effect of HBE in HD, especially on motor function and QoL. No significant adverse events were reported. The current results support the clinical effect of HBE intervention on motor function and QoL in HD patients. However, these results should be taken with caution due to the limited available evidence. Well-designed clinical studies that consider the disease severity and stages are required in the future.

Functional Intercellular Transmission of miHTT via Extracellular Vesicles: An In Vitro Proof-of-Mechanism Study

Huntington's disease (HD) is a fatal neurodegenerative disorder caused by GAG expansion in exon 1 of the huntingtin (HTT) gene. AAV5-miHTT is an adeno-associated virus serotype 5-based vector expressing an engineered HTT-targeting microRNA (miHTT). Preclinical studies demonstrate the brain-wide spread of AAV5-miHTT following a single intrastriatal injection, which is partly mediated by neuronal transport. miHTT has been previously associated with extracellular vesicles (EVs), but whether EVs mediate the intercellular transmission of miHTT remains unknown. A contactless culture system was used to evaluate the transport of miHTT, either from a donor cell line overexpressing miHTT or AAV5-miHTT transduced neurons. Transfer of miHTT to recipient (HEK-293T, HeLa, and HD patient-derived neurons) cells was observed, which significantly reduced HTT mRNA levels. miHTT was present in EV-enriched fractions isolated from culture media. Immunocytochemical and in situ hybridization experiments showed that the signal for miHTT and EV markers co-localized, confirming the transport of miHTT within EVs. In summary, we provide evidence that an engineered miRNA-miHTT-is loaded into EVs, transported across extracellular space, and taken up by neighboring cells, and importantly, that miHTT is active in recipient cells downregulating HTT expression. This represents an additional mechanism contributing to the widespread biodistribution of AAV5-miHTT.

Natural History and Burden of Huntington's Disease in the UK: A Population-Based Cohort Study

BACKGROUND

Huntington's disease (HD) is a rare neurodegenerative disease that presents with progressive psychological, cognitive and motor impairment. These diverse symptoms place a high burden on the patient, families and the healthcare systems they rely on. This study aimed to describe the epidemiology and clinical burden in individuals with HD compared with controls from the general population.

METHODS

This cohort study utilised data from general practitioner (GP) medical records to estimate the prevalence and incidence of HD between Jan 2000 and Dec 2018. A cohort of incident HD cases were matched 1:3 to controls from the general population, in whom common clinical diagnoses, medications and healthcare interventions were compared at the time of first recorded diagnosis and at a time close to death. Incidence rates of common diagnoses and mortality were compared with matched controls in the time following HD diagnosis.

RESULTS

Prevalence of HD increased between 2000 and 2018, whilst incidence remained stable. Prevalence of psychiatric diagnoses and symptomatic treatments were higher in HD cases than controls. A higher relative risk of psychotic disorders, depression, insomnia, dementia, weight loss, pneumonia and falls was observed in HD cases. Risk of death was >4 times higher in HD, with a median survival of ~12 years from first recorded diagnosis.

CONCLUSIONS

This study demonstrates the significant and progressive clinical burden in individuals up to 18 years after first recorded diagnosis.

Safety and Feasibility of Research Lumbar Puncture in Huntington's Disease: The HDClarity Cohort and Bioresource

BACKGROUND

Biomarkers are needed to monitor disease progression, target engagement and efficacy in Huntington's disease (HD). Cerebrospinal fluid (CSF) is an ideal medium to research such biomarkers due to its proximity to the brain.

OBJECTIVE

To investigate the safety and feasibility of research lumbar punctures (LP) in HD.

METHODS

HDClarity is an ongoing international biofluid collection initiative built on the Enroll-HD platform, where clinical assessments are recorded. It aims to recruit 1,200 participants. Biosamples are collected following an overnight fast: blood via venipuncture and CSF via LP. Participants are healthy controls and HD gene expansion carriers across the disease spectrum. We report on monitored data from February 2016 to September 2019.

RESULTS

Of 448 participants screened, 398 underwent at least 1 sampling visit, of which 98.24% were successful (i.e., CSF was collected), amounting to 10,610 mL of CSF and 8,200 mL of plasma. In the total 572 sampling visits, adverse events were reported in 24.13%, and headaches of any kind and post-LP headaches in 14.86% and 12.24%, respectively. Frequencies were less in manifest HD; gender, age, body mass index and disease burden score were not associated with the occurrence of the events in gene expansion carriers. Headaches and back pain were the most frequent adverse events.

CONCLUSION

HDClarity is the largest CSF collection initiative to support scientific research into HD and is now stablished as a leading resource for HD research. Our data confirm that research LP in HD are feasible and acceptable to the community, and have a manageable safety profile.

Geographic Barriers Drive Disparities in Specialty Center Access for Older Adults with Huntington's Disease

BACKGROUND

Huntington's Disease Society of America Centers of Excellence (HDSA COEs) are primary hubs for Huntington's disease (HD) research opportunities and accessing new treatments. Data on the extent to which HDSA COEs are accessible to individuals with HD, particularly those older or disabled, are lacking.

OBJECTIVE

To describe persons with HD in the U.S. Medicare program and characterize this population by proximity to an HDSA COE.

METHODS

We conducted a cross-sectional study of Medicare beneficiaries ages ≥65 with HD in 2017. We analyzed data on benefit entitlement, demographics, and comorbidities. QGis software and Google Maps Interface were employed to estimate the distance from each patient to the nearest HDSA COE, and the proportion of individuals residing within 100 miles of these COEs at the state level.

RESULTS

Among 9,056 Medicare beneficiaries with HD, 54.5% were female, 83.0% were white; 48.5% were ≥65 years, but 64.9% originally qualified for Medicare due to disability. Common comorbidities were dementia (32.4%) and depression (35.9%), and these were more common in HD vs. non-HD patients. Overall, 5,144 (57.1%) lived within 100 miles of a COE. Race/ethnicity, sex, age, and poverty markers were not associated with below-average proximity to HDSA COEs. The proportion of patients living within 100 miles of a center varied from < 10% (16 states) to > 90% (7 states). Most underserved states were in the Mountain and West Central divisions.

CONCLUSION

Older Medicare beneficiaries with HD are frequently disabled and have a distinct comorbidity profile. Geographical, rather than sociodemographic factors, define the HD population with limited access to HDSA COEs.

Risk of mortality from suicide in patients with Huntington's disease is increased compared to the general population in England

Objective

To examine the relative risk of suicide mortality in patients with Huntington’s disease (HD).

Methods

A case–control study design was used. We used linked electronic records from primary care, secondary care and Office for National Statistics from England from 2001 through 2019. Controls were matched to cases by general practice and suicide date. Odds ratios (ORs) were adjusted for gender and age at suicide/index date.

Results

Data were available for 594,674 individuals. Patients with HD who died from suicide were significantly younger at time of death than patients with HD who died from causes other than suicide (p < 0.001). The adjusted OR for HD was 9.2 (95% confidence intervals, CI 4.9–17.4) compared to those without HD. The increase in risk was higher amongst the younger age group who were ≤ 45.8 years at suicide/index date (OR 54.5, 95% CI 10.8–276.1).

Conclusion

The markedly elevated suicide risk in patients with HD suggests that implementation of suicide risk assessment may improve survival in individuals with these diseases, especially in younger patients.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00415-022-11085-z.

Effects of Percutaneous Endoscopic Gastrostomy in Patients With Huntington Disease

Objective

To determine the impact of percutaneous endoscopic gastrostomy (PEG) tubes in patients with advanced Huntington disease (HD).

Methods

A retrospective chart review of patients with HD was conducted to assess the rate of pneumonia and pressure ulcer, length of life, changes in weight, and serologic nutritional measures. Surviving and deceased patients with and without PEG tubes were compared using descriptive statistical analysis.

Results

One hundred forty-eight records were reviewed (39 patients with PEG tubes). The mean age of patients still alive and diagnosed with HD was 58.3 ± 12.7 years and age at death (n = 62) 57.7 ± 10.3 years. At the time of analysis, the mean duration of HD was 14.2 ± 7 years. Groups were similar in sex, age, and weight at admission. In those deceased, insertion of a PEG tube increased the length of life with HD by 3.6 years (16.2 ± 6.7 vs 13.2 ± 4.9 years). PEG tube placement significantly reduced cholesterol levels, increased the prevalence of skin ulcers and the rate of pneumonia. Insertion of a PEG tube did not significantly change weight or albumin levels.

Conclusions

PEG tube placement in advanced HD provided benefit in the length of life, but weight, other nutritional measures, and the rate of pneumonia were either not impacted or worsened with the insertion of a PEG tube. Impact on quality of life needs further study, but providers, patients, and families should consider all options when discussing preferences for interventions.

Classification of Evidence

This study provides Class IV evidence that for patients with advanced HD, PEG tube placement increases the length of life but has no or negative impacts on nutritional measures.

A MDS Evidence-Based Review on Treatments for Huntington's Disease

BACKGROUND

Huntington's disease (HD) is a rare neurodegenerative disorder with protean clinical manifestations. Its management is challenging, consisting mainly of off-label treatments.

OBJECTIVES

The International Parkinson and Movement Disorder Society commissioned a task force to review and evaluate the evidence of available therapies for HD gene expansion carriers.

METHODS

We followed the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. Eligible randomized controlled trials were identified via an electronic search of the CENTRAL, MEDLINE, and EMBASE databases. All eligible trials that evaluated one or more of 33 predetermined clinical questions were included. Risk of bias was evaluated using the Cochrane Risk of Bias tool. A framework was adapted to allow for efficacy and safety conclusions to be drawn from the balance between the GRADE level of evidence and the importance of the benefit/harm of the intervention.

RESULTS

Twenty-two eligible studies involving 17 interventions were included, providing data to address 8 clinical questions. These data supported a likely effect of deutetrabenazine on motor impairment, chorea, and dystonia and of tetrabenazine on chorea. The data did not support a disease-modifying effect for premanifest and manifest HD. There was no eligible evidence to support the use of specific treatments for depression, psychosis, irritability, apathy, or suicidality. Similarly, no evidence was eligible to support the use of physiotherapy, occupational therapy, exercise, dietary, or surgical treatments.

CONCLUSIONS

Data for therapeutic interventions in HD are limited and support only the use of VMAT2 inhibitors for specific motor symptoms. © 2021 International Parkinson and Movement Disorder Society.

Huntington's Disease in Israel: A Population-Based Study Using 20 Years of Routinely-Collected Healthcare Data

BACKGROUND

Huntington's disease (HD) is a rare, genetic, neurodegenerative disease. Obtaining population-level data on epidemiology and disease management is challenging.

OBJECTIVE

To investigate the epidemiology, clinical manifestations, treatment, and healthcare utilization of patients with HD in Israel.

METHODS

Retrospective population-based cohort study, including 20 years of routinely collected data from Maccabi Healthcare Services, an insurer and healthcare provider for one-quarter of the Israeli population.

RESULTS

The study cohort included 109 adult patients (aged ≥18 years) diagnosed with HD, with mean age of 49.9 years and 56%females. The most common HD-related conditions were anxiety (40%), behavioral problems (34%), sleep disorders (21%), and falls (13%). Annual incidence rates for HD ranged from 0.17 to 1.34 per 100,000 from 2000 to 2018; the 2018 crude prevalence in adults was 4.36 per 100,000. Median survival from diagnosis was approximately 12 years (95%CI: 10.4-15.3). The most frequent symptomatic treatments were antidepressants (69%), antipsychotics (63%), and tetrabenazine (63%), the only drug approved for the treatment of HD chorea in Israel during the examined period. Patterns of healthcare utilization changed as disease duration increased, reflected by increased frequency of emergency department visits and home visits.

CONCLUSION

This retrospective population-based study provides insights into the prevalence, incidence, clinical profile, survival, and resource utilization of patients with HD in ethnically diverse Israel. The findings in this study are generally consistent with the international literature and demonstrate the value of routinely collected healthcare data as a complementary resource in HD research.

Incidence of completed suicide and suicide attempts in a global prospective study of Huntington's disease

BACKGROUND

Risk of death from suicide in Huntington's disease is notably elevated relative to that in the general population, although the incidence within HD populations has not been precisely defined. Robust incidence estimates of suicidal behavior can serve as references for HD therapeutic research and post-marketing surveillance to help evaluate the suicidality risk of novel therapeutics.

AIMS

To estimate the incidence rate of completed suicide and suicide attempt in the global, prospective HD cohort study Enroll-HD that records these events per protocol.

METHOD

A total of 20 912 participants were available for analysis (HD gene-expansion carriers (HDGECs) n = 15 924; non-HDGECs n = 4988) representing a collective observation period of 53 390 participant-years. Each observed event was subject to clinical review and evaluation. We generated incidence rates (events per 100 000 person-years) for suicides and suicide attempts using all available data, as well as by year of study and geographical region. Proportionate mortality statistics for suicide and respective 95% confidence intervals were also generated.

RESULTS

The overall incidence rate of suicide in HDGECs was 72 per 100 000 person-years, and 8 per 100 000 person-years in non-HDGECs. Proportionate mortality attributable to suicide in HDGECs was 4.6%. For suicide attempts, the global overall incidence rate observed in HDGECs was 306-375 per 100 000 person-years, and 23-38 per 100 000 person-years in non-HDGECs.

CONCLUSIONS

The incidence estimates calculated here can be used as a reference to help evaluate drug safety and may also be useful in assessing progress in clinical care for HDGECs once therapeutic interventions become widely available.

Disparities in Palliative Care Utilization Among Hospitalized People With Huntington Disease: A National Cross-Sectional Study

BACKGROUND

People with Huntington's disease (HD) often become institutionalized and more frequently die away from the home setting. The reasons behind differences in end-of-life care are poorly understood. Less than 5% of people with HD report utilization of palliative care (PC) or hospice services, regardless of the lack of curative therapies for this neurodegenerative disease. It is unknown what factors are associated with in-patient specialty PC consultation in this population and how PC might be related to discharge disposition.

OBJECTIVES

To determine what HD-specific (e.g., psychosis) and serious illness-specific factors (e.g., resuscitation preferences) are associated with PC encounters in people with HD and explore how PC encounters are associated with discharge disposition.

DESIGN

We analyzed factors associated with PC consultation for people with HD using discharge data from the National Inpatient Sample and the Nationwide Inpatient Sample (NIS), Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality. An anonymized, cross-sectional, and stratified sample of 20% of United States hospitalizations from 2007 through 2014 were included using ICD-9 codes.

RESULTS

8521 patients with HD were admitted to the hospital. Of those, 321 (3.8%) received specialty PC. Payer type, (specifically private insurer or other insurer as compared to Medicare), income, (specifically the top quartile as compared to the bottom quartile), mortality risk, D.N.R., aspiration pneumonia, and depression were significantly associated with PC in a multivariate model. Among those who received PC, the odds ratio (OR) of discharge to a facility was 0.43 (95% CI, 0.32-0.58), whereas the OR of discharge to home with services was 2.25 (95% CI 1.57-3.23), even after adjusting for possible confounders.

CONCLUSIONS

Among patients with HD, economic factors, depression, and serious illness-specific factors were associated with PC, and PC was associated with discharge disposition. These findings have implications for the adaptation of inpatient PC models to meet the needs of persons with HD.

Meaning and purpose in Huntington's disease: a longitudinal study of its impact on quality of life

Objective

Previous work in Huntington’s disease (HD) has shown that a sense of meaning and purpose (M&P) is positively associated with positive affect and well‐being (PAW); however, it was unknown whether HD‐validated patient‐reported outcomes (PROs) influence this association and how M&P impacts PROs in the future. Our study was designed to examine if HD‐validated PROs moderate the relationship between M&P and PAW and to evaluate if baseline M&P predicts 12‐ and 24‐month changes in HD‐validated PROs.

Methods

This was a longitudinal, multicenter study to develop several PROs (e.g., specific for the physical, emotional, cognitive, and social domains) for people with HD (HDQLIFE). The sample consisted of 322 people with HD (n = 50 prodromal, n = 171 early‐stage manifest, and n = 101 late‐stage manifest HD). A single, multivariate linear mixed‐effects model was performed with PAW as the outcome predicted by main effects for M&P and several moderators (i.e., an HD‐validated PRO) and interactions between M&P and a given PRO. Linear‐mixed models were also used to assess if baseline M&P predicted HD‐validated PROs at 12 and 24 months.

Results

Higher M&P was positively associated with higher PAW regardless of the magnitude of symptom burden, as represented by HD‐validated PROs, and independent of disease stage. In our primary analysis, baseline M&P predicted increased PAW and decreased depression, anxiety, anger, emotional/behavioral disruptions, and cognitive decline at 12 and 24 months across all disease stages.

Interpretation

These findings parallel those seen in the oncology population and have implications for adapting and developing psychotherapeutic and palliative HD interventions.

Utility of Huntington's Disease Assessments by Disease Stage: Floor/Ceiling Effects

Introduction: An understanding of the clinimetric properties of clinical assessments, including their constraints, is critical to sound clinical study and trial design. Utilizing data from Enroll-HD—a global, prospective HD observational study and clinical research platform—we examined several well-established HD clinical assessments across all stages of disease for evidence of instrument constraints, specifically floor/ceiling effects, to inform selection of appropriate instruments for use in future studies/trials and identify gaps in instrument utility over the life-course of the disease.

Material and Methods: Analyzing publicly available data from 6,614 HD gene-expansion carriers (HDGECs), we grouped participants into deciles based on baseline CAP score, which ranged from 26 to 229. We used descriptive statistics to characterize data distribution for 25 outcome measures (encompassing motor, function, cognition, and psychiatric/behavioral domains) in each CAP decile. A skewness statistic threshold of ±2 was defined a priori to indicate floor/ceiling effects.

Results: We found evidence of floor/ceiling effects in the early premanifest stages of disease for most motor and function assessments (e.g., TMS, TFC) and select cognitive tasks (MMSE, Trail Making tests). Other cognitive assessments, and the HADS-SIS scales, performed well ubiquitously, with no evidence of floor/ceiling effects at any disease stage. Floor/ceiling effects were evident at every disease stage for certain assessments, including PBA-s measures. Ceiling effects were apparent for DCL from onset stages onwards, as expected.

Discussion: Developing instruments sensitive to subtle differences in performance at the earlier stages of the disease spectrum, particularly in motor and function domains, is warranted.

A qualitative meta-synthesis of evidence (meta-ethnography) exploring the personal experiences of gastrostomy tube in neurodegenerative diseases: a case of motor neurone disease

PURPOSE

The lived experiences of a gastrostomy tube (GT) in adults with neurodegenerative diseases (NDDs) are not well understood. The aim of this qualitative meta-synthesis was to review and synthesise the available evidence to inform clinical practice and identify research gaps.

METHODS

Meta-ethnographic synthesis of qualitative studies was conducted with systematic searching of eight databases from inception to March 2021. Qualitative studies reporting personal experiences of GTs in adults with NDDs were identified. New theories were developed during translation of concepts from each study and combined as a "line-of-argument" synthesis. Patient and public involvement was incorporated as two of the authors are living with an NDD and a GT.

RESULTS AND CONCLUSIONS

Of 2863 unique records identified, only nine fulfilled the review criteria. All studies recruited participants with motor neurone disease (MND); no other NDDs were represented. Two main themes emerged: decision making and living with GT. Decision making was the predominant theme and data regarding living with GT were sparse. There is limited research on the lived experience of a GT in adults with NDDs. The lived experience of GT in MND is complex and individualised. Future research is indicated to inform clinical practice.Implications for rehabilitationEvidence related to the lived experiences of gastrostomy tube (GT) in neurodegenerative diseases (NDDs) is lacking especially in relation to the time after GT insertion.Decision making in relation to GT is a complex and individualised psychological process for some people, while others perceive no decisional conflict.Support from healthcare professionals is crucial during the decision-making time and should not cease after GT insertion.Support from healthcare professionals can help resolve any clinical complications and also incorporate GT into everyday routines.Healthcare professionals should be aware that their views on the benefits and problems related to GT may differ to those of individuals with a NDD.

An Australian Neuro-Palliative perspective on Huntington's disease: a case report

BACKGROUND

Huntington's Disease (HD) is an incurable, progressive neuro-degenerative disease. For patients with HD access to palliative care services is limited, with dedicated Neuro-Palliative Care Services rare in Australia. We discuss the experiences of and benefits to a patient with late-stage HD admitted to our Neuro-Palliative Care service.

CASE PRESENTATION

We present the case of a patient with a 16-year history of HD from time of initial genetic testing to admission to our Neuro-Palliative Care service with late-stage disease.

CONCLUSIONS

Given the prolonged, fluctuating and heterogenous HD trajectory, measures need to be implemented to improve earlier access to multi-specialty integrative palliative care services. Given the good outcomes of our case, we strongly advocate for the role of specialised Neuro-Palliative Care services to bridge the gap between clinical need and accessibility.

Validation of diagnostic codes and epidemiologic trends of Huntington disease: a population-based study in Navarre, Spain

BACKGROUND

There is great heterogeneity on geographic and temporary Huntington disease (HD) epidemiological estimates. Most research studies of rare diseases, including HD, use health information systems (HIS) as data sources. This study investigates the validity and accuracy of national and international diagnostic codes for HD in multiple HIS and analyses the epidemiologic trends of HD in the Autonomous Community of Navarre (Spain).

METHODS

HD cases were ascertained by the Rare Diseases Registry and the reference Medical Genetics Centre of Navarre. Positive predictive values (PPV) and sensitivity with 95% confidence intervals (95% CI) were estimated. Overall and 9-year periods (1991-2017) HD prevalence, incidence and mortality rates were calculated, and trends were assessed by Joinpoint regression.

RESULTS

Overall PPV and sensitivity of combined HIS were 71.8% (95% CI: 59.7, 81.6) and 82.2% (95% CI: 70.1, 90.4), respectively. Primary care data was a more valuable resource for HD ascertainment than hospital discharge records, with 66% versus 50% sensitivity, respectively. It also had the highest number of "unique to source" cases. Thirty-five per cent of HD patients were identified by a single database and only 4% by all explored sources. Point prevalence was 4.94 (95% CI: 3.23, 6.65) per 100,000 in December 2017, and showed an annual 6.1% increase from 1991 to 1999. Incidence and mortality trends remained stable since 1995-96, with mean annual rates per 100,000 of 0.36 (95% CI: 0.27, 0.47) and 0.23 (95% CI: 0.16, 0.32), respectively. Late-onset HD patients (23.1%), mean age at onset (49.6 years), age at death (66.6 years) and duration of disease (16.7 years) were slightly higher than previously reported.

CONCLUSION

HD did not experience true temporary variations in prevalence, incidence or mortality over 23 years of post-molecular testing in our population. Ascertainment bias may largely explain the worldwide heterogeneity in results of HD epidemiological estimates. Population-based rare diseases registries are valuable instruments for epidemiological studies on low prevalence genetic diseases, like HD, as long as they include validated data from multiple HIS and genetic/family information.

Brain-derived neurotrophic factor in cerebrospinal fluid and plasma is not a biomarker for Huntington's disease

Brain-derived neurotrophic factor (BDNF) is implicated in the survival of striatal neurons. BDNF function is reduced in Huntington's disease (HD), possibly because mutant huntingtin impairs its cortico-striatal transport, contributing to striatal neurodegeneration. The BDNF trophic pathway is a therapeutic target, and blood BDNF has been suggested as a potential biomarker for HD, but BDNF has not been quantified in cerebrospinal fluid (CSF) in HD. We quantified BDNF in CSF and plasma in the HD-CSF cohort (20 pre-manifest and 40 manifest HD mutation carriers and 20 age and gender-matched controls) using conventional ELISAs and an ultra-sensitive immunoassay. BDNF concentration was below the limit of detection of the conventional ELISAs, raising doubt about previous CSF reports in neurodegeneration. Using the ultra-sensitive method, BDNF concentration was quantifiable in all samples but did not differ between controls and HD mutation carriers in CSF or plasma, was not associated with clinical scores or MRI brain volumetric measures, and had poor ability to discriminate controls from HD mutation carriers, and premanifest from manifest HD. We conclude that BDNF in CSF and plasma is unlikely to be a biomarker of HD progression and urge caution in interpreting studies where conventional ELISA was used to quantify CSF BDNF.

Composite UHDRS Correlates With Progression of Imaging Biomarkers in Huntington's Disease

BACKGROUND

The composite Unified Huntington's Disease Rating Scale (cUHDRS) is a multidimensional measure of progression in Huntington's disease (HD) being used as a primary outcome in clinical trials investigating potentially disease-modifying huntingtin-lowering therapies.

OBJECTIVE

Evaluating volumetric and structural connectivity correlates of the cUHDRS.

METHODS

One hundred and nineteen premanifest and 119 early-HD participants were included. Gray and white matter (WM) volumes were correlated with cUHDRS cross-sectionally and longitudinally using voxel-based morphometry. Correlations between baseline fractional anisotropy (FA); mean, radial, and axial diffusivity; and baseline cUHDRS were examined using tract-based spatial statistics.

RESULTS

Worse performance in the cUHDRS over time correlated with longitudinal volume decreases in the occipito-parietal cortex and centrum semiovale, whereas lower baseline scores correlated with decreased volume in the basal ganglia and surrounding WM. Lower cUHDRS scores were also associated with reduced FA and increased diffusivity at baseline.

CONCLUSION

The cUHDRS correlates with imaging biomarkers and tracks atrophy progression in HD supporting its biological relevance. © 2021 International Parkinson and Movement Disorder Society.

Huntington's disease in Turkey: genetic counseling, clinical features, and outcome

Objective: This study aims to report the data of genetic counseling and to identify the clinical features of Turkish Huntington's disease (HD) patients and to investigate its possible relationship with genetic data.Method: A regular weekly outpatient clinic has been held routinely since January 2018. Patients and their referred relatives have been evaluated regarding clinical features and genetic counseling. The database of our collaborative team was used for the study.Results: Total 141 individuals have been evaluated. Among 84 subjects genetic counseling was given, diagnosis of HD was confirmed genetically in 34 (42.0%) of individuals (25 were symptomatic-HD, 9 were presymptomatic-HD). Fifty-seven patients were previously diagnosed with HD. The mean age of onset was 42.4 (11.9) years. Chorea was mostly reported initial symptom. The mean CAG repeat number of the expanded allele was 44.1 (5.1) and correlated inversely with the age of onset (p < 0.001). During a 4.8 (3.1) year follow-up, 10% of the patients were deceased. At the last visit, over half of patients had all of the movement, behavioral and cognitive problems, and 41.6% of them had required 24-hr supervision appropriate (UHDRS-independence score 64.6 (24.4)). Paternal inheritance was related to higher CAG repeats, younger age of disease onset, and higher UHDRS-motor scores.Conclusion: HD in Turkey is a severe disabling disease affecting a younger adult population. Over half of patients had all of the movement, behavioral and cognitive problems. Genetic counseling gives the opportunity to diagnose subjects at the pre-symptomatic phase. A collaborative approach is rational in the management of HD.

Age of onset and behavioral manifestations in Huntington's disease: An Enroll-HD cohort analysis

Huntington's disease is associated with motor, cognitive and behavioral dysfunction. Behavioral symptoms may present before, after, or simultaneously with clinical disease manifestation. The relationship between age of onset and behavioral symptom presentation and severity was explored using the Enroll-HD database. Manifest individuals (n = 4469) were initially divided into three groups for preliminary analysis: early onset (<30 years; n = 479); mid-adult onset (30-59 years; n = 3478); and late onset (>59 years; n = 512). Incidence of behavioral symptoms reported at onset was highest in those with early onset symptoms at 26% (n = 126), compared with 19% (n = 678) for mid-adult onset and 11% (n = 56) for late onset (P < 0.0001). Refined analysis, looking across the continuum of ages rather than between categorical subgroups found that a one-year increase in age of onset was associated with a 5.6% decrease in the odds of behavioral symptoms being retrospectively reported as the presenting symptom (P < 0.0001). By the time of study enrollment, the odds of reporting severe behavioral symptoms decreased by 5.5% for each one-year increase in reported age of onset. Exploring environmental, genetic and epigenetic factors that affect age of onset and further characterizing types and severity of behavioral symptoms may improve treatment and understanding of Huntington's disease's impact on affected individuals.

Psychiatric morbidity and poor follow-up underlie suboptimal functional and survival outcomes in Huntington's disease

Background

Huntington’s disease (HD), an inherited, often late-onset, neurodegenerative disorder, is considered to be a rare, orphan disease. Research into its genetic correlates and services for those affected are inadequate in most low-middle income countries, including India. The apparent ‘incurability’ often deters symptomatic and rehabilitative care, resulting in poor quality of life and sub-optimal outcomes. There are no studies assessing disease burden and outcomes from India.

Methods

We attempted to evaluate individuals diagnosed to have HD at our tertiary-care center between 2013 and 2016 for clinical symptoms, functionality, mortality, follow up status through a structured interview, clinical data from medical records and UHDRS-TFC scoring.

Results

Of the 144 patients, 25% were untraceable, and another 17 (11.8%) had already died. Mean age at death and duration of illness at the time of death, were 53 years and 7 years respectively, perhaps due to suicides and other comorbidities at an early age. The patients who could be contacted (n = 81) were assessed for morbidity and total functional capacity (TFC). Mean CAG repeat length and TFC score were 44.2 and 7.5 respectively. Most individuals (66%) were in TFC stage I and II and could perhaps benefit from several interventions. The TFC score correlated inversely with duration of illness (p < 0.0001). The majority were being taken care of at home, irrespective of the physical and mental disability. There was a high prevalence of psychiatric morbidity (91%) including suicidal tendency (22%). Three of the 17 who died had committed suicide, and several other families reported suicidal history in other family members. Only about half the patients (57%) maintained a regular clinical follow-up.

Conclusions

This study demonstrates the poor follow-up rates, significant suicidality and other psychiatric symptoms, sub-optimal survival durations and functional outcomes highlighting the need for holistic care for the majority who appear to be amenable to interventions.

A Systematic Review of Rehabilitation for Corticobulbar Symptoms in Adults with Huntington's Disease

Background:

Corticobulbar symptoms have been reported in all stages of Huntington’s disease (HD); aspiration pneumonia associated with swallowing impairment has been identified as the most common cause of death. Whilst recent research has described positive effects of corticobulbar rehabilitation in other neurodegenerative conditions, it is unclear if this is similarly effective in HD. Preliminary evidence in corticospinal rehabilitation has revealed physical therapy and exercise could be beneficial for individuals with HD.

Objective:

This systematic review will explore the literature relative to rehabilitation of corticobulbar symptoms in adults with HD.

Methods:

Two investigators independently searched relevant electronic databases for literature related to corticobulbar rehabilitation in HD, published in English until October 2019. Included studies were critically appraised using the Oxford Centre for Evidence-based Medicine Levels of Evidence, Cochrane Risk of Bias Tool and Scottish Intercollegiate Guidelines Network checklists. Study outcomes included measurements of function, quality of life or neuromuscular physiology.

Results:

Seventy-seven publications were screened with eight studies meeting the inclusion criteria – two randomised control trials and six intervention studies. Validated and objective outcome measures of corticobulbar symptoms were infrequently used. There was a high risk of bias identified in 7/8 studies. The data suggested positive clinical outcomes, no adverse effects and no deterioration observed across longitudinal studies.

Conclusions:

This systematic review documented a lack of high-quality evidence to support the use of rehabilitation to treat corticobulbar symptoms in HD. However, the suggestion of potential positive effects based on available, albeit limited, studies provides justification for further research in this area.

Suicidal ideation and behavior in Huntington's disease: Systematic review and recommendations

BACKGROUND

An increased risk of suicide in Huntington's disease (HD) patients is well documented, with rates significantly higher than those of the general population as well as other neurodegenerative diseases. However, despite its prevalence, the magnitude of this phenomenon as well as its predictors and etiology are still poorly understood.

METHODS

We performed the first systematic review of all the studies published between March 1993 and December 2018 which investigated HD patients and gene carriers that reported suicidal ideation, suicide attempt, or suicide as an outcome.

RESULTS

This review reveals that some aspects of suicidality in HD are more clearly understood than others. We confirm an increased risk of suicidal ideation, suicide attempt, and suicide for HD patients. We found that suicidal ideation is elevated throughout the course of the disease, and that psychiatric comorbidities are common risk factors with depression being the most prominent.

LIMITATIONS

Important data are still largely missing, specifically regarding cognitive and neuroanatomical mechanisms and potential effective interventions. Moreover, inconsistencies in terminology, assessment tools, and outcome measures limit the comparability of the research and the conclusions that can be drawn.

CONCLUSIONS

Incidence of suicidal ideation, suicide attempt, and suicide are higher among those with HD relative to the non-HD population. It is therefore important that suicidal thoughts and behaviors are closely monitored in HD clinics and that clinical trials use standardized scales. Future research should focus on better understanding the etiology of this high suicide risk and on testing the efficacy of potential interventions.

Cerebrospinal fluid flow dynamics in Huntington's disease evaluated by phase contrast MRI

Multiple targeted therapeutics for Huntington's disease are now in clinical trials, including intrathecally delivered compounds. Previous research suggests that CSF dynamics may be altered in Huntington's disease, which could be of paramount relevance to intrathecal drug delivery to the brain. To test this hypothesis, we conducted a prospective cross-sectional study comparing people with early stage Huntington's disease with age- and gender-matched healthy controls. CSF peak velocity, mean velocity and mean flow at the level of the cerebral aqueduct, and sub-arachnoid space in the upper and lower spine, were quantified using phase contrast MRI. We calculated Spearman's rank correlations, and tested inter-group differences with Wilcoxon rank-sum test. Ten people with early Huntington's disease, and 10 controls were included. None of the quantified measures was associated with potential modifiers of CSF dynamics (demographics, osmolality, and brain volumes), or by known modifiers of Huntington's disease (age and HTTCAG repeat length); and no significant differences were found between the two studied groups. While external validation is required, the attained results are sufficient to conclude tentatively that a clinically relevant alteration of CSF dynamics - that is, one that would justify dose-adjustments of intrathecal drugs - is unlikely to exist in Huntington's disease.

Evidence of cardiac electrical remodeling in patients with Huntington disease

OBJECTIVE

Although Huntington's disease (HD) is a disease of the central nervous system, HD mortality surveys indicate heart disease as a major cause of death. Cardiac dysfunction in HD might be a primary consequence of peripherally expressed mutant huntingtin or secondary to either a general decline in health or the onset of neurological dysfunction. The aim of the study was to clarify the heart muscle involvement.

MATERIALS AND METHODS

We measured conventional and advanced resting ECG indices. Thirty-one subjects with a confirmed huntingtin gene mutation and 31 age- and gender-matched controls were included. The HD subjects were divided into four groups based on their Unified Huntington Disease Rating Scale (UHDRS) motor score.

RESULTS

We detected changes in advanced ECG variables connected with electrical ventricular remodeling (t test, p < 0.01). The increase in the unexplained part of both QT variability and the standard deviation of normal-to-normal QT intervals, presumably reflecting beat-to-beat changes in repolarization, was most pronounced. Further, both variables correlated with the product of the cytosine-adenine-guanine (CAG) triplets' repeat length and the subjects' age (CAP), the former R = 0.423 (p = 0.018) and the latter R = 0.499 (p = 0.004). There was no correlation between the CAP score and any of variables representing autonomic nervous system activity.

CONCLUSIONS

Both autonomic nervous system dysfunction and cardiac electrical remodeling are present in patients with HD. The changes in advanced ECG variables observed in the study evolve with HD progression. The increased values of QT unexplained variability may be a marker of temporal inhomogeneity in ventricular repolarization associated with malignant ventricular arrhythmias.

Fifteen Years of Clinical Trials in Huntington's Disease: A Very Low Clinical Drug Development Success Rate

BACKGROUND

Drug development in Huntington's disease (HD) is particularly challenging, and only two compounds are approved by the FDA. It is therefore essential to appraise drug development programs in order to understand the reasons for their failure during the early stages of development.

OBJECTIVES

To describe the landscape of HD therapeutic development and critically explore the causes of compound attrition in the different stages of drug development, from phase 1 to phase 4.

METHODS

All HD clinical trials registered in the WHO International Clinical Trials Search Portal, from inception to May 2017, were analyzed. Two independent authors selected and extracted data. Success rate in a trial phase was calculated as the number of compounds that progressed to the next trial phase divided by the number of compounds in that phase. The overall success rate was calculated as the ratio between the number of compounds that receive regulatory approval and the total number of compounds.

RESULTS

Ninety-nine trials assessing 41 compounds and eleven non-pharmacological interventions (devices and cell therapies) were identified. Twenty-four (24.2%) were phase 1 trials, 46 (46.5%) phase 2, 20 (20.2%) phase 3, and two (2.0%) phase 4. Sixty trials (60.6%) received industry sponsorship. The most frequently studied compounds were creatine, latrepirdine and pridopidine. The mean number of participants enrolled was 92.0 and the length of treatment was 262.9 days, and both increased from phase 1 to phase 3 trials. The success rate was 25.0% from phase 1 to phase 2, 19.4% from phase 2 to phase 3, and 14.3% from phase 3 to approval. The overall success rate was 3.5%.

CONCLUSIONS

Although HD is a rare condition, 99 HD trials were identified in a comprehensive clinical trial registry. We found a low success rate at earlier phases of drug-development and a very low trial success rate at later phases. There is a significant gap between drug discovery and development success rates that warrants careful appraisal and improvement.