Oropharyngeal Dysphagia Phenotypes Across Huntington's Disease Stages: Endoscopic Findings and Tongue Pressure Analysis.

Background: Oropharyngeal dysphagia (OD) is a common symptom in Huntington's disease (HD) and is associated with severe health and psychosocial consequences. Different OD phenotypes are defined on the basis of characteristic patterns at fiberoptic endoscopic evaluation of swallowing (FEES), and they may vary during disease progression. Objective: To describe OD phenotypes in different HD stages and to analyze their association with neurological data and tongue pressure measurements. Methods: Twenty-four patients with HD at different stages of disease progression underwent a FEES. Data on penetration/aspiration, pharyngeal residue, and OD phenotypes were gained. Neurological examination was performed with the Unified Huntington's Disease Rating Scale (UHDRS). Patient Maximum tongue pressure (MTP) and tongue endurance were measured. Results: We confirmed that the occurrence of penetration/aspiration increased with disease duration and pharyngeal residue increased from 16.7% to 100% , respectively. The most common OD phenotypes were oropharyngeal dyspraxia (91.7% ), posterior oral incontinence (87.5% ), and delayed pharyngeal phase (87.5% ). These types of dysfunctions are already detectable in >80% of patients in the early disease stages. In more advanced stages, we also observed propulsion deficit (66.7% ), resistive issue (54.2% ), and protective deficit (37.5% ). Propulsion deficit was associated with higher disease stage, greater motor dysfunction (UHDRS-I), and lower MTP and tongue endurance (p <  0.05). Conclusions: OD in HD results from a combination of different swallowing phenotypes. Early assessment of swallowing and periodical follow-ups are necessary to monitor OD severity and phenotypes and to revise diet recommendations.

Validity, diagnostics and feasibility of the Italian version of the Montreal Cognitive Assessment (MoCA) in Huntington's disease.

BACKGROUND: This study is aimed at assessing the clinimetric properties and feasibility of the Italian version of the Montreal Cognitive Assessment (MoCA) in patients with Huntington's disease (HD). METHODS: N = 39 motor-manifest HD patients, N = 74 Parkinson's disease (PD) patients and N = 92 matched HCs were administered the MoCA. HD patients further underwent the Unified Huntington's Disease Rating Scale (UHDRS), self-report questionnaires for anxiety and depression and a battery of first- and second-level cognitive tests. Construct validity was tested against cognitive and behavioural/psychiatric measures, whereas ecological validity against motor-functional subscales of the UHDRS. Sensitivity to disease severity was tested, via a logistic regression, by exploring whether the MoCA discriminated between patients in Shoulson-Fahn stage ≤ 2 vs. > 2. The same analysis was employed to test its ability to discriminate HD patients from HCs and PD patients. RESULTS: The MoCA converged towards cognitive and behavioural measures but diverged from psychiatric ones, being also associated with motor/functional measures from the UHDRS. In identifying patients with cognitive impairment, adjusted MoCA scores were highly accurate (AUC = .92), yielding optimal diagnostics at the cut-off of < 19.945 (J = .78). The MoCA was able to discriminate patients in the middle-to-advanced from those in the early-to-middle stages of the disease (p = .037), as well as to differentiate HD patients from both HCs (p < .001) and PD patients (p < .001). CONCLUSIONS: The MoCA is a valid, diagnostically sound and feasible cognitive screener in motor-manifest HD patients, whose adoption is thus encouraged in clinical practice and research.

Validity and diagnostics of the Italian version of the Montreal Cognitive Assessment (MoCA) in non-demented Parkinson's disease patients.

BACKGROUND: This study aimed at: (1) assessing, in an Italian cohort of non-demented Parkinson's disease (PD) patients, the construct validity of the Montreal Cognitive Assessment (MoCA) against both first- and second-level cognitive measures; (2) delivering an exhaustive and updated evaluation of its diagnostic properties. METHODS: A retrospective cohort of N = 237 non-demented PD patients having been administered the MoCA was addressed, of whom N = 169 further underwent the Mini-Mental State Examination (MMSE) and N = 68 the Parkinson's Disease Cognitive Rating Scale (PD-CRS). A subsample (N = 60) also underwent a second-level cognitive battery encompassing measures of attention/executive functioning, language, memory, praxis and visuo-spatial abilities. Construct validity was assessed against both the PD-CRS and the second-level cognitive battery. Diagnostics were tested via receiver-operating characteristics analyses against a below-cut-off MMSE score. RESULTS: The MoCA was associated with both PD-CRS scores (p < .001) and the vast majority of second-level cognitive measures (ps < .003). Both raw and adjusted MoCA scores proved to be highly accurate to the aim of identifying patients with MMSE-confirmed cognitive dysfunctions. A MoCA score adjusted for age and education according to the most recent normative dataset and < 19.015 is herewith suggested as indexing cognitive impairment in this population (AUC = .92; sensitivity = .92; specificity = .80). DISCUSSION: The Italian MoCA is a valid and diagnostically sound screener for global cognitive inefficiency in non-demented PD patients. Further studies are nevertheless needed that confirm its diagnostic values against a measure other than the MMSE.

Clinimetrics of the Italian version of the Montreal Cognitive Assessment (MoCA) in adult-onset idiopathic focal dystonia.

This study aimed at assessing the clinimetrics of the Montreal Cognitive Assessment (MoCA) in an Italian cohort of patients with adult-onset idiopathic focal dystonia (AOIFD). N = 86 AOIFD patients and N = 92 healthy controls (HCs) were administered the MoCA. Patients further underwent the Trail-Making Test (TMT) and Babcock Memory Test (BMT), being also screened via the Beck Depression Inventory-II (BDI-II) and the Dimensional Apathy Scale (DAS). Factorial structure and internal consistency were assessed. Construct validity was tested against TMT, BMT, BDI-II and DAS scores, whilst diagnostics against the co-occurrence of a defective performance on at least one TMT measure and on the BMT. Case-control discrimination was examined. The association between MoCA scores and motor-functional measures was explored. The MoCA was underpinned by a mono-component structure and acceptably reliable at an internal level. It converged towards TMT and BMT scores, as well as with the DAS, whilst diverging from the BDI-II. Its adjusted scores accurately detected cognitive impairment (AUC = .86) at a cut-off of < 17.212. The MoCA discriminated patients from HCs (p < .001). Finally, it was unrelated to disease duration and severity, as well as to motor phenotypes. The Italian MoCA is a valid, diagnostically sound and feasible cognitive screener in AOIFD patients.

Clinimetrics and feasibility of the Italian version of the Frontal Assessment Battery (FAB) in non-demented Parkinson's disease patients.

BACKGROUND: This study aimed at assessing the cross-sectional and longitudinal clinimetrics and feasibility of the Frontal Assessment Battery (FAB) in non-demented Parkinson's disease (PD) patients. METHODS: N = 109 PD patients underwent the FAB and the Montreal Cognitive Assessment (MoCA). A subsample of patients further underwent a thorough motor, functional and behavioral evaluation (the last including measures of anxiety, depression and apathy). A further subsample was administered a second-level cognitive battery tapping on attention, executive functioning, language, memory, praxis and visuo-spatial abilities. The following properties of the FAB were tested: (1) concurrent validity and diagnostics against the MoCA; (2) convergent validity against the second-level cognitive battery; (4) association with motor, functional and behavioral measures; (5) capability to discriminate patients from healthy controls (HCs; N = 96); (6) assessing its test-retest reliability, susceptibility to practice effects and predictive validity against the MoCA, as well as deriving reliable change indices (RCIs) for it, at a ≈ 6-month interval, within a subsample of patients (N = 33). RESULTS: The FAB predicted MoCA scores at both T0 and T1, converged with the vast majority of second-level cognitive measures and was associated with functional independence and apathy. It accurately identified cognitive impairment (i.e., a below-cut-off MoCA score) in patients, also discriminating patients from HCs. The FAB was reliable at retest and free of practice effects; RCIs were derived according to a standardized regression-based approach. DISCUSSION: The FAB is a clinimetrically sound and feasible screener for detecting dysexecutive-based cognitive impairment in non-demented PD patients.

Diagnostic properties of the Frontal Assessment Battery (FAB) in Huntington's disease.

Background: This study aimed at assessing the diagnostic properties of the Frontal Assessment Battery (FAB) as to its capability to (1) discriminate healthy controls (HCs) from patients with Huntington's disease (HD) and (2) identify cognitive impairment in this population. Materials: Thirty-eight consecutive HD patients were compared to 73 HCs on the FAB. Patients further underwent the Montreal Cognitive Assessment (MoCA) and the Unified Huntington's Disease Rating Scale (UHDRS). Receiver-operating characteristics (ROC) analyses were run to assess both intrinsic-i.e., sensitivity (Se) and specificity (Sp), and post-test diagnostics, positive and negative predictive values (PPV; NPV) and likelihood ratios (LR+; LR-), of the FAB both in a case-control setting and to identify, within the patient cohort, cognitive impairment (operationalized as a below-cut-off MoCA score). In patients, its diagnostic accuracy was also compared to that of the cognitive section of the UHDRS (UHDRS-II). Results: The FAB and UHDRS-II were completed by 100 and 89.5% of patients, respectively. The FAB showed optimal case-control discrimination accuracy (AUC = 0.86-0.88) and diagnostic properties (Se = 0.68-0.74; Sp = 0.88-0.9; PPV = 0.74-0.8; NPV = 0.84-0.87; LR+ = 5.6-7.68; LR- = 0.36-0.29), performing even better (AUC = 0.9-0.91) at identifying cognitive impairment among patients (Se = 0.73-1; Sp = 0.86-0.71; PPV = 0.79-0.71; NPV = 0.82-1; LR+ =5.13-3.5; LR- = 0.31-0) and comparably to the UHDRS-II (89% vs. 85% of accuracy, respectively; p = 0.46). Discussion: In HD patients, the FAB is highly feasible for cognitive screening aims, being also featured by optimal intrinsic/post-test diagnostics within both case-control and case-finding settings.

Semiology and determinants of apathy across neurodegenerative motor disorders: A comparison between amyotrophic lateral sclerosis, Parkinson's and Huntington's disease.

Background: The semiology and determinants of apathy are largely unknown across amyotrophic lateral sclerosis (ALS), Parkinson's disease (PD), and Huntington's disease (HD), due to both motor and non-motor confounders. This study thus aimed at (1) profiling apathy in ALS, PD, and HD and (2) exploring its clinical determinants. Materials: Consecutive ALS (N = 99), PD (N = 73), and HD (N = 25) patients underwent a motor-free assessment of apathy (Dimensional Apathy Scale, DAS), global cognition, anxiety and depression. Function was assessed through disease-specific scales. The DAS was also completed by N = 101 healthy controls (HCs). Between-group comparisons on DAS scores were implemented by covarying for all applicable confounders. Predictive models on DAS scores were built through multiple, stepwise regressions. Results: Parkinson's disease and HD, but not ALS, patients were more apathetic than HCs-with HD patients also selectively showing lower initiation and poorer goal-directed planning than HCs. Higher apathetic features were detected in PD and HD as compared to ALS. Education was a protective factor against apathy in ALS. Anxiety was a risk factor for global apathy in ALS, HD, and to a lesser extent, in PD, whereas, protective only toward affective disintegration in PD and ALS. Cognitive inefficiency was a risk factor toward apathy in both PD and ALS. Depression was a risk factor for executive-related apathy in PD. Discussion: This study provides unprecedented insights into the heterogeneous semiology and determinants of apathy across ALS, PD, and HD via the DAS, in turn informing clinical practice and research.

Progressive motor neuron syndromes with single CNS lesions and CSF oligoclonal bands: never forget solitary sclerosis!

We describe 3 cases of solitary sclerosis (SS), a rare condition characterized by a single inflammatory demyelinating lesion in the white matter of the brain or spinal cord. All patients had progressive limb motor impairment (patient 1, 66-year-old female: left spastic hemiparesis; patient 2, 39-year-old male: right spastic hemiparesis; patient 3, 42-year-old female: proximally predominant left upper limb weakness with amyotrophy and fasciculations). In all patients, MRI disclosed a single small T2-hyperintense demyelinating lesion: in the right anterior paramedian upper medulla, in the median-left paramedian anterior lower medulla, and in the left paramedian anterior cervical spinal cord at C4 level, respectively. In patients 1 and 2, transcranial magnetic stimulation (TMS) demonstrated altered motor evoked potentials (MEPs) and increased central motor conduction time (CMCT) in the affected limbs; in patient 3, needle EMG revealed chronic neurogenic changes in C5-C7 muscles of left upper limb. Patients 1 and 2 had normal brain 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET). CSF analysis demonstrated IgG oligoclonal bands in all patients. In patients 2 and 3, levels of neurofilament light chain (NFL) in CSF and serum, respectively, were within normal limits. The three cases were consistent with the diagnosis of SS. Notably, while the first two cases mimicked Mills' syndrome (the hemiparetic variant of primary lateral sclerosis, PLS), the third one was rather reminiscent of amyotrophic lateral sclerosis (ALS). This suggests including SS in the differential diagnosis not only of PLS, but also of ALS. We also report the first quantification of NFL levels in SS.

Hands-feet wireless devices: Test-retest reliability and discriminant validity of motor measures in Parkinson's disease telemonitoring.

BACKGROUND: Telemonitoring, a branch of telemedicine, involves the use of technological tools to remotely detect clinical data and evaluate patients. Telemonitoring of patients with Parkinson's disease (PD) should be performed using reliable and discriminant motor measures. Furthermore, the method of data collection and transmission, and the type of subjects suitable for telemonitoring must be well defined. OBJECTIVE: To analyze differences in patients with PD and healthy controls (HC) with the wearable inertial device SensHands-SensFeet (SH-SF), adopting a standardized acquisition mode, to verify if motor measures provided by SH-SF have a high discriminating capacity and high intraclass correlation coefficient (ICC). METHODS: Altogether, 64 patients with mild-to-moderate PD and 50 HC performed 14 standardized motor activities for assessing bradykinesia, postural and resting tremors, and gait parameters. SH-SF inertial devices were used to acquire movements and calculate objective motor measures of movement (total: 75). For each motor task, five or more biomechanical parameters were measured twice. The results were compared between patients with PD and HC. RESULTS: Fifty-eight objective motor measures significantly differed between patients with PD and HC; among these, 32 demonstrated relevant discrimination power (Cohen's d > 0.8). The test-retest reliability was excellent in patients with PD (median ICC = 0.85 right limbs, 0.91 left limbs) and HC (median ICC = 0.78 right limbs, 0.82 left limbs). CONCLUSION: In a supervised environment, the SH-SF device provides motor measures with good results in terms of reliability and discriminant ability. The reliability of SH-SF measurements should be evaluated in an unsupervised home setting in future studies.

Parkinsonian Syndromes in Motor Neuron Disease: A Clinical Study.

Background: Parkinsonian syndromes may rarely occur in motor neuron disease (MND). However, previous studies are heterogeneous and mostly case reports or small case series. Therefore, we aimed to identify and characterize patients with concurrent parkinsonian syndromes extracted from a cohort of 1,042 consecutive cases diagnosed with MND at a tertiary Italian Center. Methods: Diagnosis of Parkinson's disease (PD), progressive supranuclear palsy (PSP) and corticobasal syndrome (CBS) was made according to current criteria. Clinical characterization included: upper and lower motor neuron disease features, typical and atypical parkinsonian features, oculomotor disorders, cognitive testing, MRI features, and, when available molecular neuroimaging. Genetic testing was carried out for major MND and PD-associated genes. Results: Parkinsonian syndromes were diagnosed in 18/1042 (1.7%) of MND patients (7 PD, 6 PSP, 3 CBS, 2 other parkinsonisms). Based on phenotype, patients could be categorized into amyotrophic lateral sclerosis (ALS)-parkinsonism and primary lateral sclerosis (PLS)-parkinsonism clusters. Across the whole database, parkinsonism was significantly more common in PLS than in other MND phenotypes (12.1 vs. 1.1%, p = 5.0 × 10-10). MND patients with parkinsonian features had older age of onset, higher frequency of oculomotor disorders, cognitive impairment, and family history of parkinsonism or dementia. Two patients showed pathogenic mutations in TARDBP and C9orf72 genes. Conclusion: Specific patterns in MND-parkinsonism were observed, with PLS patients often showing atypical parkinsonian syndromes and ALS patients more frequently showing typical PD. Systematic clinical, genetic, and neuropathologic characterization may provide a better understanding of these phenotypes.

Predictors of malnutrition risk in neurodegenerative diseases: The role of swallowing function.

BACKGROUND AND PURPOSE: Oropharyngeal dysphagia is generally recognized to increase the risk of malnutrition; however, its role in patients with neurodegenerative disease has yet to be determined. This cross-sectional study aimed to investigate the impact of swallowing function on malnutrition risk in patients with neurodegenerative diseases. METHODS: Patients with oral nutrition and diagnosis of Huntington disease (HD), Parkinson disease (PD), or amyotrophic lateral sclerosis (ALS) were recruited. Demographic and clinical data were collected. The swallowing assessment included a fiberoptic endoscopic evaluation of swallowing, an oral phase assessment, and a meal observation scored with the Mealtime Assessment Scale (MAS). Malnutrition risk was assessed with the Mini Nutritional Assessment. RESULTS: Overall, 148 patients were recruited (54 HD, 33 PD, and 61 ALS). One hundred (67.6%) patients were considered at risk of malnutrition. In the multivariate analysis, age ≥ 65 years (odds ratio [OR] = 3.16, p = 0.014), disease severity (moderate vs mild OR = 3.89, severe vs mild OR = 9.71, p = 0.003), number of masticatory cycles (OR = 1.03, p = 0.044), and MAS safety (OR = 1.44, p = 0.016) were significantly associated with malnutrition risk. CONCLUSIONS: Prolonged oral phase and signs of impaired swallowing safety during meals, together with older age and disease severity, are independent predictors of malnutrition risk in neurodegenerative diseases. This study broadens the focus on dysphagia, stressing the importance of early detection not only of pharyngeal signs, but also of oral phase impairment and meal difficulties through a multidimensional swallowing assessment.

Ecological Validity of the Montreal Cognitive Assessment in Non-Demented Parkinson's Disease Patients.

BACKGROUND: The ecological validity of performance-based cognitive screeners needs to be tested in order for them to be fully recommended for use within clinical practice and research. OBJECTIVES: The objective of this study was to examine, within an Italian cohort of non-demented Parkinson's disease (PD) patients, the ecological validity of the Montreal Cognitive Assessment (MoCA) by assessing its association with (1) functional independence (FI), (2) quality of life (QoL), and (3) behavioural-psychological (BP) outcomes. METHODS: Seventy-four non-demented PD patients were administered the MoCA and underwent motor functional - i.e., Unified Parkinson's Disease Rating Scale (UPDRS), Modified Hoehn-Yahr Scale (HY), and Schwab and England Scale (SES) -, behavioural and psychological - i.e., State- and Trait-Anxiety Inventory-Form Y (STAI-Y1/-Y2), Beck Depression Inventory (BDI), and Dimensional Apathy Scale (DAS) - and QoL evaluations - i.e., MOS 36-Item Short Form Health Survey (SF-36). Associations of interest against FI, QoL, and BP outcomes were tested via Bonferroni-corrected Pearson's/Spearman's correlations while covarying for demographics, disease duration as well as UPDRS-III, UPDRS-IV, and HY scores. Intake of psychotropic drugs was also covaried when assessing the association between the MoCA and BP/QoL measures. RESULTS: MoCA scores were significantly associated with the SES (rs(73) = 0.34; p = 0.005) and the DAS-Executive (r(67) = -0.47; p < 0.001), while not to other FI/BP outcomes and QoL measures. CONCLUSIONS: The MoCA is a valid estimate of daily life functional autonomy in non-demented PD patients, also reflecting apathetic features of a dysexecutive nature.

Early Dysfunction of Substantia Nigra Dopamine Neurons in the ParkinQ311X Mouse.

Mutations in the PARK2 gene encoding the protein parkin cause autosomal recessive juvenile parkinsonism (ARJP), a neurodegenerative disease characterized by early dysfunction and loss of dopamine (DA) neurons in the substantia nigra pars compacta (SNc). No therapy is currently available to prevent or slow down the neurodegeneration in ARJP patients. Preclinical models are key to clarifying the early events that lead to neurodegeneration and reveal the potential of novel neuroprotective strategies. ParkinQ311X is a transgenic mouse model expressing in DA neurons a mutant parkin variant found in ARJP patients. This model was previously reported to show the neuropathological hallmark of the disease, i.e., the progressive loss of DA neurons. However, the early dysfunctions that precede neurodegeneration have never been investigated. Here, we analyzed SNc DA neurons in parkinQ311X mice and found early features of mitochondrial dysfunction, extensive cytoplasmic vacuolization, and dysregulation of spontaneous in vivo firing activity. These data suggest that the parkinQ311X mouse recapitulates key features of ARJP and provides a useful tool for studying the neurodegenerative mechanisms underlying the human disease and for screening potential neuroprotective drugs.

Compensating for verbal-motor deficits in neuropsychological assessment in movement disorders: sensitivity and specificity of the ECAS in Parkinson's and Huntington's diseases.

INTRODUCTION: The study aims at investigating psychometric properties of the Edinburgh cognitive and behavioural ALS screen (ECAS) in Parkinson's (PD) and Huntington's (HD) diseases. The sensitivity and specificity of the ECAS in highlighting HD and PD cognitive-behavioural features and in differentiating between these two populations and from healthy controls (HC) were evaluated. Moreover, correlations between the ECAS and traditional cognitive measures, together with core clinical features, were analysed. METHODS: Seventy-three PD patients, 38 HD patients, and 49 education-matched healthy participants were enrolled. Participants were administered the ECAS, together with other cognitive screening tools and psychological questionnaires. Patients' behavioural assessment was also carried out with carers. RESULTS: The ECAS distinguished between HD patients and HC and between the two clinical syndromes with high sensitivity and specificity. Even if the diagnostic accuracy of the ECAS in distinguishing between PD and HC was low, the PD cognitive phenotype was very well described by the ECAS performances. Convergent validity of the ECAS against other traditional cognitive screening was observed, as well as correlations with psychological aspects and typical clinical features, especially for the HD group. CONCLUSIONS: The ECAS represents a rapid and feasible tool, useful also in other neurodegenerative disorders affecting verbal-motor abilities than the amyotrophic lateral sclerosis such as PD and HD. Clinical applications in these neurodegenerative conditions require further investigations and, probably, some adaptations of the original test.

Counterfactual thinking in psychiatric and neurological diseases: A scoping review.

BACKGROUND: The ability to simulate alternatives to factual events is called counterfactual thinking (CFT) and it is involved both in emotional and behavioral regulation. CFT deficits have been reported in psychiatric and neurological conditions, possibly contributing to patients' difficulties in modulating behaviors and affections. Thus, acknowledging the presence and possible consequences of CFT impairments might be essential for optimal clinical management. OBJECTIVES: This scoping review aims to summarize the previous evidence about CFT in psychiatric and neurological diseases to determine the extent of the previous research and what has been discovered so far, the variety of clinical conditions considered, the methodologies adopted, and the relevant issues to be addressed by future investigations. METHODS: PsycInfo, PubMed, Scopus, and Web of Science were searched to identify articles published up to January 2020, written in English and focused on CFT in adults affected by psychiatric or neurological conditions. RESULTS: Twenty-nine studies have been included; most of them focused on psychiatric conditions, a minority considered neurological diseases. The generation of counterfactual thoughts related to a negative real-life or a fictional event and the counterfactual inference test were the most popular tasks adopted. CFT impairments were reported in both psychiatric and neurological conditions, likely associated with a fronto-executive dysfunction. CONCLUSIONS: Future research might further explore CFT in those psychiatric and neurological conditions in which CFT difficulties have been preliminary reported. Furthermore, it would be recommendable to extend this investigation to all the clinical conditions possibly at risk of fronto-executive dysfunction. In the end, we speculate that since CFT plays a role in driving everyday behaviors, it might be crucial also when medical decisions are involved; thus, future research might extend the investigation of CFT especially to those populations that implicate complex clinical management.

Pharmacological antagonism of kainate receptor rescues dysfunction and loss of dopamine neurons in a mouse model of human parkin-induced toxicity.

Mutations in the PARK2 gene encoding the protein parkin cause autosomal recessive juvenile Parkinsonism (ARJP), a neurodegenerative disease characterized by dysfunction and death of dopamine (DA) neurons in the substantia nigra pars compacta (SNc). Since a neuroprotective therapy for ARJP does not exist, research efforts aimed at discovering targets for neuroprotection are critically needed. A previous study demonstrated that loss of parkin function or expression of parkin mutants associated with ARJP causes an accumulation of glutamate kainate receptors (KARs) in human brain tissues and an increase of KAR-mediated currents in neurons in vitro. Based on the hypothesis that such KAR hyperactivation may contribute to the death of nigral DA neurons, we investigated the effect of KAR antagonism on the DA neuron dysfunction and death that occur in the parkinQ311X mouse, a model of human parkin-induced toxicity. We found that early accumulation of KARs occurs in the DA neurons of the parkinQ311X mouse, and that chronic administration of the KAR antagonist UBP310 prevents DA neuron loss. This neuroprotective effect is associated with the rescue of the abnormal firing rate of nigral DA neurons and downregulation of GluK2, the key KAR subunit. This study provides novel evidence of a causal role of glutamate KARs in the DA neuron dysfunction and loss occurring in a mouse model of human parkin-induced toxicity. Our results support KAR as a potential target in the development of neuroprotective therapy for ARJP.

Fiberoptic endoscopic evaluation of swallowing in early-to-advanced stage Huntington's disease.

Huntington's disease (HD) is a neurodegenerative disorder characterized by motor disturbances, cognitive decline, and behaviour changes. A well-recognized feature of advanced HD is dysphagia, which leads to malnutrition and aspiration pneumonia, the latter being the primary cause of death in HD. Previous studies have underscored the importance of dysphagia in HD patients with moderate-to-advanced stage disease, but it is unclear whether dysphagia affects patients already at an early stage of disease and whether genetic or clinical factors can predict its severity. We performed fiberoptic endoscopic evaluation of swallowing (FEES) in 61 patients with various stages of HD. Dysphagia was found in 35% of early-stage, 94% of moderate-stage, and 100% of advanced-stage HD. Silent aspiration was found in 7.7% of early-stage, 11.8% of moderate-stage, and 27.8% of advanced-stage HD. A strong correlation was observed between disease progression and dysphagia severity: worse dysphagia was associated with worsening of motor symptoms. Dysphagia severity as assessed by FEES correlated with Huntington's Disease Dysphagia Scale scores (a self-report questionnaire specific for evaluating swallowing in HD). The present findings add to our understanding of dysphagia onset and progression in HD. A better understanding of dysphagia onset and progression in HD may inform guidelines for standard clinical care in dysphagia, its recognition, and management.