Neuropsychiatric Burden in Huntington's Disease

Huntington's disease is a disorder that results in motor, cognitive, and psychiatric problems. The symptoms often take different forms and the presence of disturbances of the psychic sphere reduces patients' autonomy and quality of life, also impacting patients' social life. It is estimated that a prevalence between 33% and 76% of the main psychiatric syndromes may arise in different phases of the disease, often in atypical form, even 20 years before the onset of chorea and dementia. We present a narrative review of the literature describing the main psychopathological patterns that may be found in Huntington's disease, searching for a related article in the main database sources (Medline, ISI Web of Knowledge, Scopus, and Medscape). Psychiatric conditions were classified into two main categories: affective and nonaffective disorders/symptoms; and anxiety and neuropsychiatric features such as apathy and irritability. Though the literature is extensive, it is not always convergent, probably due to the high heterogeneity of methods used. We summarize main papers for pathology and sample size, in order to present a synoptic vision of the argument. Since the association between Huntington's disease and psychiatric symptoms was demonstrated, we argue that the prevalent and more invalidating psychiatric components should be recognized as early as possible during the disease course in order to best address psychopharmacological therapy, improve quality of life, and also reduce burden on caregivers

Onset and evolution of dysphagia in Huntington’s Disease

Background Huntington's disease (HD) is a neurodegenerative disorder characterized by motor disturbances, cognitive decline and behaviour changes. Dysphagia is a well-recognized feature in advanced HD stage that leads to malnutrition and aspiration pneumonia, the latter representing the first causes of death in HD. However, no data are available about the onset of dysphagia during the disease course and the correlation between dysphagia severity and disease progression. Aim The aim of the study was to characterize dysphagia in patients with HD from early to advanced stages of the disease. Methods Dysphagia was investigated in 43 patients with HD by fiberoptic endoscopic examination of swallowing (FEES). FEES recordings were de-identified and assessed by a blinded judge. Dysphagia Outcome and Severity Scale (DOSS), Penetration-Aspiration Scale (PAS), and Yale Pharyngeal Residue Severity Rating Scale (YALE) were used to rate dysphagia severity, swallowing safety, and swallowing efficacy, respectively. For disease severity, all patients were assessed with the Unified Huntington's Disease Rating Scale (UHDRS) and were classi\ufb01ed as early-stage, moderate-stage or advanced stage HD based on Shoulson-Fahn stages. Results FEES was well tolerated in all the subjects. Data showed that 30% of early-stage patients with HD already exhibit dysphagia (DOSS 645). Prevalence of dysphagia noticeably increased to 90% in the moderate stage of the disease, while reached 100% in the advanced stage. PAS scores progressively worsened with the disease stage. On the contrary, YALE scores remained stable in the various stages of disease and showed a greater amount of residue in the valleculae compared to pyriform sinus. A Total Motor Score of the UHDRS >37 correctly identified patients with dysphagia with 82% sensitivity and 73% specificity. Conclusion This study provides a better understanding of dysphagia onset and development in HD and may guide the definition of clinical care standard for dysphagia recognition and management, aimed at reducing nutritional and pulmonary complications

Defining the role of the Bcl-2 family proteins in Huntington's disease

B-cell lymphoma 2 (Bcl-2) family proteins regulate survival, mitochondria morphology dynamics and metabolism in many cell types including neurons. Huntington's disease (HD) is a neurodegenerative disorder caused by an expanded CAG repeat tract in the IT15 gene that encodes for the protein huntingtin (htt). In vitro and in vivo models of HD and HD patients' tissues show abnormal mitochondrial function and increased cell death rates associated with alterations in Bcl-2 family protein expression and localization. This review aims to draw together the information related to Bcl-2 family protein alterations in HD to decipher their potential role in mutated htt-related cell death and mitochondrial dysfunction

Brain-Computer Interface for Clinical Purposes : Cognitive Assessment and Rehabilitation

Alongside the best-known applications of brain-computer interface (BCI) technology for restoring communication abilities and controlling external devices, we present the state of the art of BCI use for cognitive assessment and training purposes. We first describe some preliminary attempts to develop verbal-motor free BCI-based tests for evaluating specific or multiple cognitive domains in patients with Amyotrophic Lateral Sclerosis, disorders of consciousness, and other neurological diseases. Then we present the more heterogeneous and advanced field of BCI-based cognitive training, which has its roots in the context of neurofeedback therapy and addresses patients with neurological developmental disorders (autism spectrum disorder and attention-deficit/hyperactivity disorder), stroke patients, and elderly subjects. We discuss some advantages of BCI for both assessment and training purposes, the former concerning the possibility of longitudinally and reliably evaluating cognitive functions in patients with severe motor disabilities, the latter regarding the possibility of enhancing patients' motivation and engagement for improving neural plasticity. Finally, we discuss some present and future challenges in the BCI use for the described purposes

Parkin regulates kainate receptors by interacting with the GluK2 subunit

Although loss-of-function mutations in the PARK2 gene, the gene that encodes the protein parkin, cause autosomal recessive juvenile parkinsonism, the responsible molecular mechanisms remain unclear. Evidence suggests that a loss of parkin dysregulates excitatory synapses. Here we show that parkin interacts with the kainate receptor (KAR) GluK2 subunit and regulates KAR function. Loss of parkin function in primary cultured neurons causes GluK2 protein to accumulate in the plasma membrane, potentiates KAR currents and increases KAR-dependent excitotoxicity. Expression in the mouse brain of a parkin mutant causing autosomal recessive juvenile parkinsonism results in GluK2 protein accumulation and excitotoxicity. These findings show that parkin regulates KAR function in vitro and in vivo, and suggest that KAR upregulation may have a pathogenetic role in parkin-related autosomal recessive juvenile parkinsonism

Brain-Derived Neurotrophic Factor in Patients with Huntington's Disease

Reduced Brain-Derived Neurotrophic Factor (BDNF) levels have been described in a number of patho-physiological conditions, most notably, in Huntington's disease (HD), a progressive neurodegenerative disorder. Since BDNF is also produced in blood, we have undertaken the measurement of its peripheral levels in the attempt to identify a possible link with HD prognosis and/or its progression. Here we evaluated BDNF level in 398 blood samples including 138 controls, 56 preHD, and 204 HD subjects. We found that BDNF protein levels were not reliably different between groups, whether measured in plasma (52 controls, 26 preHD, 105 HD) or serum (39 controls, 5 preHD, 29 HD). Our experience, and a reanalysis of the literature highlighted that intra-group variability and methodological aspects affect this measurement, especially in serum. We also assessed BDNF mRNA levels in blood samples from 47 controls, 25 preHD, and 70 HD subjects, and found no differences among the groups. We concluded that levels of BDNF in human blood were not informative (mRNA levels or plasma protein level) nor reliable (serum protein levels) as HD biomarkers. We also wish to warn the scientific community in interpreting the significance of changes measured in BDNF protein levels in serum from patients suffering from different conditions

Mutant Huntingtin induces activation of the Bcl-2/adenovirus E1B 19-kDa interacting protein (BNip3)

Huntington's disease (HD) is a neurodegenerative disorder characterized by progressive neuronal death in the basal ganglia and cortex. Although increasing evidence supports a pivotal role of mitochondrial dysfunction in the death of patients' neurons, the molecular bases for mitochondrial impairment have not been elucidated. We provide the first evidence of an abnormal activation of the Bcl-2/adenovirus E1B 19-kDa interacting protein 3 (BNip3) in cells expressing mutant Huntingtin. In this study, we show an abnormal accumulation and dimerization of BNip3 in the mitochondria extracted from human HD muscle cells, HD model cell cultures and brain tissues from HD model mice. Importantly, we have shown that blocking BNip3 expression and dimerization restores normal mitochondrial potential in human HD muscle cells. Our data shed light on the molecular mechanisms underlying mitochondrial dysfunction in HD and point to BNip3 as a new potential target for neuroprotective therapy in HD

Biofluid Biomarkers in Huntington's Disease

Huntington's disease (HD) is a chronic progressive neurodegenerative condition where new markers of disease progression are needed. So far no disease-modifying interventions have been found, and few interventions have been proven to alleviate symptoms. This may be partially explained by the lack of reliable indicators of disease severity, progression, and phenotype.Biofluid biomarkers may bring advantages in addition to clinical measures, such as reliability, reproducibility, price, accuracy, and direct quantification of pathobiological processes at the molecular level; and in addition to empowering clinical trials, they have the potential to generate useful hypotheses for new drug development.In this chapter we review biofluid biomarker reports in HD, emphasizing those we feel are likely to be closest to clinical applicability

The pseudopolyneuritic form of Amyotrophic Lateral Sclerosis (Patrikios' disease)

The line distinguishing motor neuron diseases (MNDs) from motor neuropathies is sometimes blurred. Among MNDs, the pseudopolyneuritic form of amyotrophic lateral sclerosis (ALS) strictly mimics a neuropathy. We describe the clinical and electrophysiological features in the early stages of the pseudopolyneuritic ALS, and assess the disease progression in eight patients. Early symptoms were unilateral foot-drop and, less commonly, paraparesis. At the clinical examination, weakness of distal and proximal leg muscles was often detected, while the hand muscles were rarely involved and craniobulbar muscles were spared. Definite upper motor neuron signs were rare in the early stages of the disease. Electromyography (EMG) showed active denervation in the lower limbs of all patients (distal > proximal) and in the paraspinal muscles of 7 patients (lumbosacral > thoracic), and more rarely in the upper limbs. Transcranial magnetic stimulation (TMS) yielded abnormal responses (low amplitude or absent cortical motor evoked potentials and prolonged central motor conduction time) in most lower-limb recordings, while mild abnormalities were rarely observed in the upper limbs. Haematologic and cerebrospinal fluid examinations were normal. Brain and spinal MRI showed no significant abnormalities. After a three years follow-up on seven patients, all cases were nonambulatory and had upper limb weakness, and most of them had bulbar dysfunction. The electrophysiological finding of both upper and lower motor neuron involvement of the lower limbs in the early stages of the disease could be a useful marker to distinguish the pseudopolyneuritic form of ALS from other MNDs and motor neuropathies