Retinal Thickness Predicts the Risk of Cognitive Decline in Parkinson Disease.

OBJECTIVE: This study was undertaken to analyze longitudinal changes of retinal thickness and their predictive value as biomarkers of disease progression in idiopathic Parkinson's disease (iPD). METHODS: Patients with Lewy body diseases were enrolled and prospectively evaluated at 3 years, including patients with iPD (n = 42), dementia with Lewy bodies (n = 4), E46K-SNCA mutation carriers (n = 4), and controls (n = 17). All participants underwent Spectralis retinal optical coherence tomography and Montreal Cognitive Assessment, and Unified Parkinson's Disease Rating Scale score was obtained in patients. Macular ganglion cell-inner plexiform layer complex (GCIPL) and peripapillary retinal nerve fiber layer (pRNFL) thickness reduction rates were estimated with linear mixed models. Risk ratios were calculated to evaluate the association between baseline GCIPL and pRNFL thicknesses and the risk of subsequent cognitive and motor worsening, using clinically meaningful cutoffs. RESULTS: GCIPL thickness in the parafoveal region (1- to 3-mm ring) presented the largest reduction rate. The annualized atrophy rate was 0.63µm in iPD patients and 0.23µm in controls (p < 0.0001). iPD patients with lower parafoveal GCIPL and pRNFL thickness at baseline presented an increased risk of cognitive decline at 3 years (relative risk [RR] = 3.49, 95% confidence interval [CI] = 1.10-11.1, p = 0.03 and RR = 3.28, 95% CI = 1.03-10.45, p = 0.045, respectively). We did not identify significant associations between retinal thickness and motor deterioration. INTERPRETATION: Our results provide evidence of the potential use of optical coherence tomography-measured parafoveal GCIPL thickness to monitor neurodegeneration and to predict the risk of cognitive worsening over time in iPD. ANN NEUROL 2021;89:165-176.

Predictors of health-related quality of life in Parkinson's disease: the impact of overlap between health-related quality of life and clinical measures.

PURPOSE: This study aimed to determine predictors of health-related quality of life (HRQoL) in Parkinson's disease (PD) and to explore their predictive value before and after controlling overlapping items between HRQoL and clinical variables. METHODS: One hundred and eight PD patients underwent motor, anxiety, depression, apathy, fatigue, and neurocognition assessment. HRQoL was assessed by the Parkinson's Disease Questionnaire-39 (PDQ-39). In order to determine predictors of HRQoL in PD, stepwise multiple regression analyses were performed in two ways: before and after removing the emotional well-being dimension from PDQ-39 to control the overlap between depression and anxiety, and HRQoL. RESULTS: HRQoL total index was predicted by anxiety, fatigue, motor symptoms, and depression, explaining 26.9%, 7.2%, 2.8%, and 1.9% of the variance. However, after removing overlapping items, HRQoL total index was predicted by fatigue (16.5%), anxiety (6.1%), motor symptoms (3.9%), and neurocognition (2.5%), but not depression. Regarding HRQoL dimensions, mobility and activities of daily living were predicted by fatigue (19.7% and 5%) and UPDRS-III (4% and 10.2%); emotional well-being by fatigue (7.9%); social support by anxiety (12.2%) and UPDRS-III (8.6%); communication by neurocognition (5.3%) and UPDRS-III (3.4%); cognition by anxiety (10.6%) and bodily discomfort by anxiety (23%) and fatigue (4.1%). CONCLUSION: These findings showed the importance of identifying and controlling overlapping items of HRQoL and clinical measures to perform an accurate interpretation. HRQoL dimensions showed different predictors before and after controlling the overlap. Based on these results fatigue, anxiety, motor symptoms, and neurocognition, but not depression are the main predictors of HRQoL in PD patients.

The maintained attention assessment in patients affected by Myalgic encephalomyelitis/chronic fatigue syndrome: a reliable biomarker?

The maintained attention is the cause of great functional limitations in CFS/ME, a disease that mainly affects women in the central period of life. Cognitive function is explored using the Montreal Cognitive Assessment, the maintained attention using the Toulouse-Piéron test with which the Global Index of Attention and Perception (GIAP) is obtained, the fatigue using the visual analog scale and the perception of effort using the modified Borg scale. The final sample were 84 patients (66 women/18 men) who met diagnostic criteria (Fukuda-1994, Carruthers-2011) and 22 healthy controls (14 women/8 men). Most of patients maintain normal cognitive function, showing low or very low attention score in the 70% of patients with a marked cognitive fatigue compared to the control group (p < 0.05). There were no significant differences between genders in GIAP or fatigue for CFS/ME; however, sick women perceive cognitive effort higher than men. Deficits in sustained attention and the perception of fatigue, so effort after performing the proposed test are a sensitive and reliable indicator that allows us to substantiate a clinical suspicion and refer patients for further studies in order to confirm or rule out CFS/ME.

Foveal Pit Morphology Characterization: A Quantitative Analysis of the Key Methodological Steps.

Disentangling the cellular anatomy that gives rise to human visual perception is one of the main challenges of ophthalmology. Of particular interest is the foveal pit, a concave depression located at the center of the retina that captures light from the gaze center. In recent years, there has been a growing interest in studying the morphology of the foveal pit by extracting geometrical features from optical coherence tomography (OCT) images. Despite this, research has devoted little attention to comparing existing approaches for two key methodological steps: the location of the foveal center and the mathematical modelling of the foveal pit. Building upon a dataset of 185 healthy subjects imaged twice, in the present paper the image alignment accuracy of four different foveal center location methods is studied in the first place. Secondly, state-of-the-art foveal pit mathematical models are compared in terms of fitting error, repeatability, and bias. The results indicate the importance of using a robust foveal center location method to align images. Moreover, we show that foveal pit models can improve the agreement between different acquisition protocols. Nevertheless, they can also introduce important biases in the parameter estimates that should be considered.

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: A Neurological Entity?

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a disorder of unknown physiopathology with multisystemic repercussions, framed in ICD-11 under the heading of neurology (8E49). There is no specific test to support its clinical diagnosis. Our objective is to review the evidence in neuroimaging and dysautonomia evaluation in order to support the neurological involvement and to find biomarkers serving to identify and/or monitor the pathology. The symptoms typically appear acutely, although they can develop progressively over years; an essential trait for diagnosis is "central" fatigue together with physical and/or mental exhaustion after a small effort. Neuroimaging reveals various morphological, connectivity, metabolic, and functional alterations of low specificity, which can serve to complement the neurological study of the patient. The COMPASS-31 questionnaire is a useful tool to triage patients under suspect of dysautonomia, at which point they may be redirected for deeper evaluation. Recently, alterations in heart rate variability, the Valsalva maneuver, and the tilt table test, together with the presence of serum autoantibodies against adrenergic, cholinergic, and serotonin receptors were shown in a subgroup of patients. This approach provides a way to identify patient phenotypes. Broader studies are needed to establish the level of sensitivity and specificity necessary for their validation. Neuroimaging contributes scarcely to the diagnosis, and this depends on the identification of specific changes. On the other hand, dysautonomia studies, carried out in specialized units, are highly promising in order to support the diagnosis and to identify potential biomarkers. ME/CFS orients towards a functional pathology that mainly involves the autonomic nervous system, although not exclusively.

Myocardial MIBG scintigraphy in genetic Parkinson's disease as a model for Lewy body disorders.

PURPOSE: To identify myocardial sympathetic denervation patterns suggestive of Lewy body (LB) pathology in patients with genetic and idiopathic parkinsonisms by 123I-metaiodobenzylguanidine (MIBG) scintigraphy. METHODS: We retrospectively analysed myocardial MIBG images acquired with a dual-head gamma camera and low-energy high-resolution collimator (LEHR) in 194 patients with suspected synucleinopathy or atypical parkinsonism, including 34 with genetic Parkinson's disease (PD; 4 PARK1, 8 PARK2 and 22 PARK8), 85 with idiopathic PD (iPD), 6 with idiopathic REM sleep behaviour disorder (iRBD), 17 with dementia with LB (DLB), 40 with multiple system atrophy (MSA) and 12 with progressive supranuclear palsy (PSP), and in 45 healthy controls. We calculated heart-to-mediastinum MIBG uptake ratios (HMR) at 15 min and 4 h (HMR4H) for the LEHR and standardized medium-energy collimators, to obtain classification accuracies and optimal cut-off values for HMR using supervised classification and ROC analyses. RESULTS: While patients with LB disorders had markedly lower HMR4HLEHR than controls (controls 1.86 ± 0.26, iPD 1.38 ± 0.29, iRBD 1.23 ± 0.09, PARK1 1.20 ± 0.09, DLB 1.17 ± 0.11; p < 0.05), for the remaining patient categories differences were smaller (PARK8 1.51 ± 0.32; p < 0.05) or not significant (MSA 1.82 ± 0.37, PSP 1.59 ± 0.23, PARK2 1.51 ± 0.30; p > 0.05). The diagnostic accuracy of HMR4HLEHR was highest in patients with LB disorders (PARK1, iPD, DLB, iRBD; 89% to 97%) and lowest in those with PARK2, PARK8, PSP and MSA (65% to 76%), with an optimal HMR4HLEHR cut-off value of 1.72 for discriminating most patients with LB disorders including iPD and 1.40 for discriminating those with aggressive LB spectrum phenotypes (DLB, PARK1 and iRBD). CONCLUSION: Our study including patients with a wide spectrum of genetic and idiopathic parkinsonisms with different degrees of LB pathology further supports myocardial MIBG scintigraphy as an accurate tool for discriminating patients with LB spectrum disorders.

Parafoveal thinning of inner retina is associated with visual dysfunction in Lewy body diseases.

BACKGROUND: Retinal optical coherence tomography findings in Lewy body diseases and their implications for visual outcomes remain controversial. We investigated whether region-specific thickness analysis of retinal layers could improve the detection of macular atrophy and unravel its association with visual disability in Parkinson's disease. METHODS: Patients with idiopathic Parkinson's disease (n = 63), dementia with Lewy bodies (n = 8), and E46K mutation carriers in the α-synuclein gene (E46K-SNCA) (n = 4) and 34 controls underwent Spectralis optical coherence tomography macular scans and a comprehensive battery of visual function and cognition tests. We computed mean retinal layer thicknesses of both eyes within 1-, 2-, 3-, and 6-mm diameter macular discs and in concentric parafoveal (1- to 2-mm, 2- to 3-mm, 1- to 3-mm) and perifoveal (3- to 6-mm) rings. Group differences in imaging parameters and their relationship with visual outcomes were analyzed. A multivariate logistic model was developed to predict visual impairment from optical coherence tomography measurements in Parkinson's disease, and cutoff values were determined with receiver operating characteristic analysis. RESULTS: When compared with controls, patients with dementia with Lewy bodies had significant thinning of the ganglion cell-inner plexiform layer complex within the central 3-mm disc mainly because of differences in 1- to 3-mm parafoveal thickness. This parameter was strongly correlated in patients, but not in controls, with low contrast visual acuity and visual cognition outcomes (P < .05, False Discovery Rate), achieving 88% of accuracy in predicting visual impairment in Parkinson's disease. CONCLUSION: Our findings support that parafoveal thinning of ganglion cell-inner plexiform complex is a sensitive and clinically relevant imaging biomarker for Lewy body diseases, specifically for Parkinson's disease. © 2019 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.

The relationship between inflammatory bowel disease and Parkinson's disease: true or fiction?

Gastrointestinal (GI) symptoms can precede by many years the motor symptoms of Parkinson's disease (PD) and these patients can show some degree of inflammation associated with abnormal aggregates of alpha-synuclein in the GI tract. The abnormal accumulation of alpha-synuclein and the spreading of the aggregates from the gut to the brain might be promoted by inflammation, rising the hypothesis of a possible relationship between inflammatory bowel disease and PD. Many population-based studies have explored this association, but they have found conflicting results. It is essential to clarify this hypothesis and to try to elucidate the milestones of this relationship. There is no clear concordance between the results and the interpretation of different previous findings, probably due to many confounding factors such as drugs with anti-inflammatory activity, surgery, genetic predisposition and also selection bias. If there is a real association between both diseases, gastroenterologists and neurologists should be able to detect possible triggers of the disease or on the other hand, protective factors, that may be considered in clinical practice.

Cardiovascular autonomic effects of vagus nerve stimulation.

The vagus nerve is responsible for the parasympathetic innervation of the major thoracic and abdominal organs. It also carries sensory afferent fibres from these viscera and reaches different brain structures. These connections have proven useful in the treatment of different diseases. Afferent stimulation of the left vagus nerve is used to treat epilepsy and major depression, and stimulation of the right vagus nerve is being tried for the treatment of heart failure. The device used for the therapy delivers intermittent stimuli. It is indicated worldwide for the treatment of drug-resistant epilepsy in patients who are not appropriate candidates for respective surgery. It has also received approval for the treatment of major depression, obesity and episodic cluster headache by the Food and Drug Administration. Randomised controlled trials and prospective studies have confirmed the efficacy and safety of this therapy in epilepsy. Nevertheless, sporadic cases of ventricular asystole have been reported. To evaluate the effect of vagus nerve stimulation therapy on the autonomic nervous system, different studies that assess heart function and blood pressure changes have been conducted, although the methods employed were not homogeneous. These studies have found subtle or no significant changes in heart rate variability and blood pressure in epileptic patients. Moreover, this therapy may reduce the risk of one of the most lethal conditions in epilepsy-sudden unexpected death.

Rehabilitation, the Great Absentee of Virtual Coaching in Medical Care: Scoping Review.

BACKGROUND: In the last few years, several studies have focused on describing and understanding how virtual coaches (ie, coaching program or smart device aiming to provide coaching support through a variety of application contexts) could be key drivers for health promotion in home care settings. As there has been enormous technological progress in the field of artificial intelligence and data processing in the past decade, the use of virtual coaches gains an augmented attention in the considerations of medical innovations. OBJECTIVE: This scoping review aimed at providing an overview of the applications of a virtual coach in the clinical field. In particular, the review focused on the papers that provide tangible information for coaching activities with an active implication for engaging and guiding patients who have an ongoing plan of care. METHODS: We aimed to investigate the use of the term virtual coach in the clinical field performing a methodical review of the relevant literature indexed on PubMed, Scopus, and Embase databases to find virtual coach papers focused on specific activities dealing with clinical or medical contexts, excluding those aimed at surgical settings or electronic learning purposes. RESULTS: After a careful revision of the inclusion and exclusion criteria, 46 records were selected for the full-text review. Most of the identified articles directly or indirectly addressed the topic of physical activity. Some papers were focused on the use of virtual coaching (VC) to manage overweight or nutritional issues. Other papers dealt with technological interfaces to facilitate interactions with patients suffering from different chronic clinical conditions such as heart failure, chronic obstructive pulmonary disease, depression, and chronic pain. CONCLUSIONS: Although physical activity is a healthy practice that is most encouraged by a virtual coach system, in the current scenario, rehabilitation is the great absentee. This paper gives an overview of the tangible applications of this tool in the medical field and may inspire new ideas for future research on VC.

Transient Ischemic Attack while Injecting Intravenous Saline Contrast in a Patient with Persistent Left Superior Vena Cava.

In this case report, we describe a patient who has a persistent left superior vena cava (PLSVC) manifesting as a transient ischemic attack (TIA) and a remote brain abscess. PLSCV, when draining in the left atrium, is a cause of right to left shunt, and it has been related to brain abscesses and, as reported in a few cases, to ischemic stroke. After admission, our patient experienced 2 new episodes of TIA while being injected with agitated saline contrast through the left arm, producing echocardiographic images of right to left shunt, which gave the clue to the diagnosis.

Orthostatic hypotension in Parkinson disease: how much you fall or how low you go?

Orthostatic hypotension (OH) is frequent in patients with Parkinson's disease (PD) and can occur with or without symptoms. Pharmacological treatments are effective, but often exacerbate supine hypertension. Guidelines exist for the diagnosis, but not for the treatment of OH. We examined the relationship between blood pressure (BP) and symptoms in a cohort of PD patients with the goal of identifying a hemodynamic target to guide treatment. We measured BP supine and upright (tilt or active standing) and identified the presence or absence of symptomatic OH by using a validated patient-reported outcome questionnaire in 210 patients with PD. We evaluated the usefulness of the 20/10 and 30/15 mmHg diagnostic criteria (systolic/diastolic) to identify symptomatic OH. Fifty percent of the PD patient cohort met criteria for the 20/10 fall and 30% for the 30/15 BP fall. Among the patients who met either OH criteria, the percentage of those with symptoms was small (33% of those with 20/10 and 44% of those with 30/15 mmHg; 16% and 13%, respectively, overall). Symptomatic OH was associated with an upright mean BP below 75 mmHg. A mean standing BP <75 mmHg had a sensitivity of 97% and a specificity of 98% for detecting symptomatic OH. Although the prevalence of OH in PD is high, not all patients have symptoms of organ hypoperfusion. A mean standing BP below 75 mmHg appears to be a useful benchmark when deciding whether the benefits of initiating pharmacological treatment of OH outweigh the risks of exacerbating supine hypertension.

Prognostic factors for falls in Parkinson's disease: a systematic review.

BACKGROUND: Falls represent a critical concern in Parkinson's disease (PD), contributing to increased morbidity and reduced quality of life. PURPOSE: We conducted a systematic review to assess the prognostic factors associated with falls in PD, aiming to provide a comprehensive overview of relevant demographic and clinical parameters, and aid neurologists in identifying subsets of PD patients most susceptible to falls and associated injuries. METHODS: PubMed and Web of Science databases were searched for prospective studies assessing factors associated with falls in ambulatory PD patients across different settings, from inception to August 2023. Data extraction was conducted using CHARMS-PF checklist and risk of bias was assessed with QUIPS tool. PRISMA guidelines were followed. RESULTS: The initial search yielded 155 references. Thirty-four studies, involving a total of 3454 PD patients, were included in the final analysis. The mean pooled age was 67.6 years, and 45.1% were women. PD patients presented mild motor impairment (UPDRS III score 27.8) with mean pooled disease duration of 5.7 years. Gait and balance disorders and history of prior falls emerged as the most consistent predictors of falls across studies. Disease duration, disease severity, dysautonomic symptoms, freezing of gait, frontal cognitive functions, and PD medication dosages yielded inconsistent findings. Conversely, dyskinesias, age, sex, and depression were unrelated to future falls in PD. Logistic regression models were most commonly employed to identify factors significantly associated with falls in PD. Substantial heterogeneity prevailed in the inclusion of confounding factors. CONCLUSION: The evidence suggests that previous history of falls, gait disorders, and poor balance are robust prognostic markers for falls in PD.

Association of retinal neurodegeneration with the progression of cognitive decline in Parkinson's disease.

Retinal thickness may serve as a biomarker in Parkinson's disease (PD). In this prospective longitudinal study, we aimed to determine if PD patients present accelerated thinning rate in the parafoveal ganglion cell-inner plexiform layer (pfGCIPL) and peripapillary retinal nerve fiber layer (pRNFL) compared to controls. Additionally, we evaluated the relationship between retinal neurodegeneration and clinical progression in PD. A cohort of 156 PD patients and 72 controls underwent retinal optical coherence tomography, visual, and cognitive assessments between February 2015 and December 2021 in two Spanish tertiary hospitals. The pfGCIPL thinning rate was twice as high in PD (ß [SE] = -0.58 [0.06]) than in controls (ß [SE] = -0.29 [0.06], p < 0.001). In PD, the progression pattern of pfGCIPL atrophy depended on baseline thickness, with slower thinning rates observed in PD patients with pfGCIPL below 89.8 µm. This result was validated with an external dataset from Moorfields Eye Hospital NHS Foundation Trust (AlzEye study). Slow pfGCIPL progressors, characterized by older at baseline, longer disease duration, and worse cognitive and disease stage scores, showed a threefold increase in the rate of cognitive decline (ß [SE] = -0.45 [0.19] points/year, p = 0.021) compared to faster progressors. Furthermore, temporal sector pRNFL thinning was accelerated in PD (ßtime x group [SE] = -0.67 [0.26] µm/year, p = 0.009), demonstrating a close association with cognitive score changes (ß [SE] = 0.11 [0.05], p = 0.052). This study suggests that a slower pattern of pfGCIPL tissue loss in PD is linked to more rapid cognitive decline, whereas changes in temporal pRNFL could track cognitive deterioration.

Brain Degeneration in Synucleinopathies Based on Analysis of Cognition and Other Nonmotor Features: A Multimodal Imaging Study.

BACKGROUND: We aimed to characterize subtypes of synucleinopathies using a clustering approach based on cognitive and other nonmotor data and to explore structural and functional magnetic resonance imaging (MRI) brain differences between identified clusters. METHODS: Sixty-two patients (n = 6 E46K-SNCA, n = 8 dementia with Lewy bodies (DLB) and n = 48 idiopathic Parkinson's disease (PD)) and 37 normal controls underwent nonmotor evaluation with extensive cognitive assessment. Hierarchical cluster analysis (HCA) was performed on patients' samples based on nonmotor variables. T1, diffusion-weighted, and resting-state functional MRI data were acquired. Whole-brain comparisons were performed. RESULTS: HCA revealed two subtypes, the mild subtype (n = 29) and the severe subtype (n = 33). The mild subtype patients were slightly impaired in some nonmotor domains (fatigue, depression, olfaction, and orthostatic hypotension) with no detectable cognitive impairment; the severe subtype patients (PD patients, all DLB, and the symptomatic E46K-SNCA carriers) were severely impaired in motor and nonmotor domains with marked cognitive, visual and bradykinesia alterations. Multimodal MRI analyses suggested that the severe subtype exhibits widespread brain alterations in both structure and function, whereas the mild subtype shows relatively mild disruptions in occipital brain structure and function. CONCLUSIONS: These findings support the potential value of incorporating an extensive nonmotor evaluation to characterize specific clinical patterns and brain degeneration patterns of synucleinopathies.

Multimodal visual system analysis as a biomarker of visual hallucinations in Parkinson's disease.

Visual hallucinations (VH) are present in up to 75% of Parkinson's disease (PD) patients. However, their neural bases and participation of the visual system in VH are not well-understood in PD. Seventy-four participants, 12 PD with VH (PDVH), 35 PD without VH (PDnoVH) and 27 controls underwent a battery of primary visual function and visual cognition tests, retinal optical coherence tomography and structural and resting-state functional brain MRI. We quantified cortical thickness with Freesurfer and functional connectivity (FC) of Visual (VIS), Fronto-Parietal (FP), Ventral Attention (VAN) and Dorsal Attention (DAN) networks with CONN toolbox. Group comparisons were performed with MANCOVA. Area Under the Curve (AUC) was computed to assess the ability of visual variables to differentiate PDVH and PDnoVH. There were no significant PDVH vs PDnoVH differences in disease duration, motor manifestations, general cognition or dopamine agonist therapy (DA) use. Compared to PDnoVH and HC, and regardless of DA use, PDVH showed significantly reduced contrast sensitivity, visuoperceptive and visuospatial abilities, increased retina photoreceptor layer thickness, reduced cortical thickness mostly in right visual associative areas, decreased between-network VIS-VAN and VAN-DAN connectivity and increased within-network DAN connectivity. The combination of clinical and imaging variables that best discriminated PDVH and PDnoVH (highest AUC), where within-network DAN FC, photoreceptor layer thickness and cube analysis test from Visual Object and Space Perception Battery (accuracy of 81.8%). Compared to PDnoVH, PDVH have specific functional and structural abnormalities within the visual system, which can be quantified non-invasively and could potentially constitute biomarkers for VH in PD.

Retinal thickness as a biomarker of cognitive impairment in manifest Huntington's disease.

BACKGROUND: Cognitive decline has been reported in premanifest and manifest Huntington's disease but reliable biomarkers are lacking. Inner retinal layer thickness seems to be a good biomarker of cognition in other neurodegenerative diseases. OBJECTIVE: To explore the relationship between optical coherence tomography-derived metrics and global cognition in Huntington's Disease. METHODS: Thirty-six patients with Huntington's disease (16 premanifest and 20 manifest) and 36 controls matched by age, sex, smoking status, and hypertension status underwent macular volumetric and peripapillary optical coherence tomography scans. Disease duration, motor status, global cognition and CAG repeats were recorded in patients. Group differences in imaging parameters and their association with clinical outcomes were analyzed using linear mixed-effect models. RESULTS: Premanifest and manifest Huntington's disease patients presented thinner retinal external limiting membrane-Bruch's membrane complex, and manifest patients had thinner temporal peripapillary retinal nerve fiber layer compared to controls. In manifest Huntington's disease, macular thickness was significantly associated with MoCA scores, inner nuclear layer showing the largest regression coefficients. This relationship was consistent after adjusting for age, sex, and education and p-value correction with False Discovery Rate. None of the retinal variables were related to Unified Huntington's Disease Rating Scale score, disease duration, or disease burden. Premanifest patients did not show a significant association between OCT-derived parameters and clinical outcomes in corrected models. CONCLUSIONS: In line with other neurodegenerative diseases, OCT is a potential biomarker of cognitive status in manifest HD. Future prospective studies are needed to evaluate OCT as a potential surrogate marker of cognitive decline in HD.

Staging Parkinson's Disease According to the MNCD (Motor/Non-motor/Cognition/Dependency) Classification Correlates with Disease Severity and Quality of Life.

BACKGROUND: Recently, a novel simple classification called MNCD, based on 4 axes (Motor; Non-motor; Cognition; Dependency) and 5 stages, has been proposed to classify Parkinson's disease (PD). OBJECTIVE: Our aim was to apply the MNCD classification in a cohort of PD patients for the first time and also to analyze the correlation with quality of life (QoL) and disease severity. METHODS: Data from the baseline visit of PD patients recruited from 35 centers in Spain from the COPPADIS cohort fromJanuary 2016 to November 2017 were used to apply the MNCD classification. Three instruments were used to assess QoL:1) the 39-item Parkinson's disease Questionnaire [PDQ-39]); PQ-10; the EUROHIS-QOL 8-item index (EUROHIS-QOL8). RESULTS: Four hundred and thirty-nine PD patients (62.05±7.84 years old; 59% males) were included. MNCD stage was:stage 1, 8.4% (N = 37); stage 2, 62% (N = 272); stage 3, 28.2% (N = 124); stage 4-5, 1.4% (N = 6). A more advancedMNCD stage was associated with a higher score on the PDQ39SI (p < 0.0001) and a lower score on the PQ-10 (p< 0.0001) and EUROHIS-QOL8 (p< 0.0001). In many other aspects of the disease, such as disease duration, levodopa equivalent daily dose, motor symptoms, non-motor symptoms, and autonomy for activities of daily living, an association between the stage and severity was observed, with data indicating a progressive worsening related to disease progression throughout the proposed stages. CONCLUSION: Staging PD according to the MNCD classification correlated with QoL and disease severity. The MNCD could be a proper tool to monitor the progression of PD.

Plasma and serum alpha-synuclein as a biomarker in Parkinson's disease: A meta-analysis.

BACKGROUND: Reliable biomarkers for Parkinson's disease (PD) diagnosis are urgently needed. Alpha-synuclein (α-syn) and its proteoforms play a key role in PD pathology but in vivo measurements have raised conflicting results, and whether α-syn in blood could distinguish PD patients from healthy controls is still controversial. METHODS: A systematic literature search yielded 35 eligible studies for meta-analysis reporting the concentration of total, oligomeric or phosphorylated α-syn in plasma and/or serum of PD patients and healthy controls. Standardized mean differences (SMD) were pooled using multivariate/multilevel linear mixed-effects models. Meta-regression analyses were conducted to investigate possible modifiers. RESULTS: A meta-analysis of 32 articles involving 2683 PD patients and 1838 controls showed a significant overall effect of PD on total α-syn levels (SMD = 0.85, p = 0.004). Meta-regression showed that increased SMD of total α-syn in PD was significantly associated with lower age, shorter disease duration, mild motor impairment, and Immunomagnetic Reduction assay for protein quantification. In contrast, no significant differences were observed for oligomeric or phosphorylated α-syn between PD and controls but increased oligomeric α-syn was significantly associated with shorter disease duration. The heterogeneity among studies was high (>98%). CONCLUSIONS: These findings suggest that increased total plasma/serum α-syn levels in PD primarily occur in early phases of the disease. The evidence obtained from a small number of studies measuring plasma/serum concentrations of oligomeric and phosphorylated species of α-syn shows no difference. The clinical applicability of measuring plasma or serum α-syn species for differentiating PD from healthy control warrants further studies with better clinical profiling of PD patients.

Potential Tear Biomarkers for the Diagnosis of Parkinson's Disease-A Pilot Study.

Parkinson's disease (PD) is the second most common neurodegenerative disease after Alzheimer's disease. In this study, the tear proteome profile of patients with idiopathic PD (iPD, n = 24), carriers of the E46K-SNCA mutation (n = 3) and healthy control (CT, n = 27) subjects was analyzed to identify candidate biomarkers for the diagnosis of PD. An observational, prospective and case-control pilot study was carried out, analyzing the participants tear samples by nano-liquid chromatography-mass spectrometry (nLC-MS/MS) and assessing their neurological impairment. The proteomic data obtained are available at ProteomeXchange with identifier 10.6019/PXD028811. These analyses led to the identification of 560 tear proteins, some of which were deregulated in PD patients and that have been implicated in immune responses, inflammation, apoptosis, collagen degradation, protein synthesis, defense, lipid transport and altered lysosomal function. Of these proteins, six were related to neurodegenerative processes and showed a good capacity to classify patients and controls. These findings revealed that certain proteins were upregulated in the tears of PD patients, mainly proteins involved in lysosomal function. Thus, in this study, tear proteins were identified that are implicated in neurodegeneration and that may be related to an aggressive disease phenotype in PD patients.