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Abstract Intravenous arachnoid granulations (AGs) are protrusions of the arachnoid membrane into the venous lumen and function as contributors to the cerebrospinal fluid (CSF) flow circuit. Patients with Parkinson disease (PD) often present with accumulation of alpha synuclein. Previous works have provided evidence for neurofluid circulation dysfunction in neurodegenerative diseases associated with changes in CSF egress, which may have implications regarding AG morphology. The present study aims to investigate group differences in AG volumetrics between healthy and PD participants, as well as relationships between AG characteristics and clinical assessments. Generalized linear models revealed significant increases in AG volumetrics and number in PD compared to healthy controls. Partial Spearman-rank correlation analyses demonstrated significant relationships between AG metrics and motor and cognitive assessments. Finally, AG volumetrics were positively correlated with objective actigraphy measures of sleep dysfunction, but not self-report sleep symptoms.

Abstract Background Parkinson’s disease is characterized by dopamine-responsive symptoms as well as aggregation of α-synuclein protofibrils. New diagnostic methods assess α-synuclein aggregation characteristics from cerebrospinal fluid (CSF) and recent pathophysiologic mechanisms suggest that CSF circulation disruptions may precipitate α-synuclein retention. Here, diffusion-weighted MRI with low-to-intermediate diffusion-weightings was applied to test the hypothesis that CSF motion is reduced in Parkinson’s disease relative to healthy participants. Methods Multi-shell diffusion weighted MRI (spatial resolution = 1.8 × 1.8 × 4.0 mm) with low-to-intermediate diffusion weightings (b-values = 0, 50, 100, 200, 300, 700, and 1000 s/mm2) was applied over the approximate kinetic range of suprasellar cistern fluid motion at 3 Tesla in Parkinson’s disease (n = 27; age = 66 ± 6.7 years) and non-Parkinson’s control (n = 32; age = 68 ± 8.9 years) participants. Wilcoxon rank-sum tests were applied to test the primary hypothesis that the noise floor-corrected decay rate of CSF signal as a function of b-value, which reflects increasing fluid motion, is reduced within the suprasellar cistern of persons with versus without Parkinson’s disease and inversely relates to choroid plexus activity assessed from perfusion-weighted MRI (significance-criteria: p

Abstract Introduction Deutetrabenazine is a vesicular monoamine transporter 2 inhibitor used to treat tardive dyskinesia (TD) and chorea associated with Huntington disease (HD). To enhance detection of safety signals across individual trials, integrated safety analyses of deutetrabenazine in TD and HD chorea were conducted. Methods For TD, safety data were integrated from two 12-week pivotal studies (ARM-TD and AIM-TD) and through week 15 of the open-label extension (OLE) study (RIM-TD). Data were analyzed by deutetrabenazine treatment group and placebo. For HD, safety data were integrated from the 12-week pivotal study (First-HD) and through week 15 of the OLE study (ARC-HD) for patients previously receiving placebo. Integrated deutetrabenazine data were compared with placebo from the pivotal study. Results For TD, deutetrabenazine (n = 384) was generally well tolerated compared with placebo (n = 130). Adverse event (AE) incidence was numerically higher in the response-driven deutetrabenazine vs the fixed-dose deutetrabenazine and placebo groups, respectively (any AE, 59.5% vs 44.4–50.0% and 53.8%; treatment-related AE, 38.1% vs 18.1–25.0% and 30.8%). Serious AEs were reported for 2.8–8.3% of patients in the deutetrabenazine groups and 6.9% in the placebo group. Common AEs (≥ 4%) included headache, somnolence, nausea, anxiety, fatigue, dry mouth, and diarrhea. AE incidence was higher during the titration vs maintenance periods. For HD, AE incidence was numerically higher with deutetrabenazine (n = 84) vs placebo (n = 45; any AE, 64.3% vs 60.0%; treatment-related AE, 38.1% vs 26.7%); serious AEs were reported for similar proportions for the deutetrabenazine and placebo groups, 2.4% and 2.2%, respectively. Common AEs (≥ 4%) included irritability, fall, depression, dry mouth, and fatigue. Conclusions Data from an integrated analysis of studies in TD and an integrated analysis of studies of chorea in HD showed that deutetrabenazine has a favorable safety profile and is well tolerated across indications. Trial Registration ClinicalTrials.gov identifiers, NCT02291861, NCT02195700, NCT01795859, NCT02198794, NCT01897896.

Abstract Background Peri-sinus structures such as arachnoid granulations (AG) and the parasagittal dural (PSD) space have gained much recent attention as sites of cerebral spinal fluid (CSF) egress and neuroimmune surveillance. Neurofluid circulation dysfunction may manifest as morphological changes in these structures, however, automated quantification of these structures is not possible and rather characterization often requires exogenous contrast agents and manual delineation. Methods We propose a deep learning architecture to automatically delineate the peri-sinus space (e.g., PSD and intravenous AG structures) using two cascaded 3D fully convolutional neural networks applied to submillimeter 3D T 2-weighted non-contrasted MRI images, which can be routinely acquired on all major MRI scanner vendors. The method was evaluated through comparison with gold-standard manual tracing from a neuroradiologist (n = 80; age range = 11–83 years) and subsequently applied in healthy participants (n = 1,872; age range = 5-100 years), using data from the Human Connectome Project, to provide exemplar metrics across the lifespan. Dice-Sørensen and a generalized linear model was used to assess PSD and AG changes across the human lifespan using quadratic restricted splines, incorporating age and sex as covariates. Results Findings demonstrate that the PSD and AG volumes can be segmented using T 2-weighted MRI with a Dice-Sørensen coefficient and accuracy of 80.7 and 74.6, respectively. Across the lifespan, we observed that total PSD volume increases with age with a linear interaction of gender and age equal to 0.9 cm3 per year (p

Abstract Background The choroid plexus functions as the blood-cerebrospinal fluid (CSF) barrier, plays an important role in CSF production and circulation, and has gained increased attention in light of the recent elucidation of CSF circulation dysfunction in neurodegenerative conditions. However, methods for routinely quantifying choroid plexus volume are suboptimal and require technical improvements and validation. Here, we propose three deep learning models that can segment the choroid plexus from commonly-acquired anatomical MRI data and report performance metrics and changes across the adult lifespan. Methods Fully convolutional neural networks were trained from 3D T1-weighted, 3D T2-weighted, and 2D T2-weighted FLAIR MRI using gold-standard manual segmentations in control and neurodegenerative participants across the lifespan (n = 50; age = 21–85 years). Dice coefficients, 95% Hausdorff distances, and area-under-curve (AUCs) were calculated for each model and compared to segmentations from FreeSurfer using two-tailed Wilcoxon tests (significance criteria: p

Abstract Objective The cerebellum has been identified as the key brain region that modulates reward processing in animal models. Consistently, we recently found that people with cerebellar ataxia have impulsive and compulsive behaviors (ICBs), the main symptoms related to abnormal reward processing. Due to the lack of a validated scale to quantitatively measure ICBs in cerebellar disorders, we aim to develop and validate a new scale, Cerebellar Impulsivity–Compulsivity Assessment (CIA). Methods We recruited 62 cerebellar ataxia cases, categorized into those with ICBs and those without. We developed a preliminary version of CIA, containing 17 questions. We studied the internal consistency, test–retest reliability, and inter‐rater reliability to formulate the final version of CIA, which constitutes only 10 questions. The receiver operating characteristic curve (ROC) was generated to assess the sensitivity and specificity of CIA. Results Cerebellar ataxia cases with ICBs have threefold higher total preliminary CIA scores than those without ICBs (12.06 ± 5.96 vs. 4.68 ± 3.50, p = 0.038). Cronbach's alpha revealed good internal consistency across all items (α > 0.70). By performing the test–retest reliability and inter‐rater reliability on the preliminary version of CIA, we excluded seven questions (r

BackgroundImpulsivity is a common clinical feature of Huntington disease (HD), but the underlying cognitive dynamics of impulse control in this population have not been well-studied.ObjectiveTo investigate the temporal dynamics of action impulse control in HD patients using an inhibitory action control task.MethodsSixteen motor manifest HD patients and seventeen age-matched healthy controls (HC) completed the action control task. We applied the activation-suppression theoretical model and distributional analytic techniques to differentiate the strength of fast impulses from their top-down suppression.ResultsOverall, HD patients produced slower and less accurate reactions than HCs. HD patients also exhibited an exacerbated interference effect, as evidenced by a greater slowing of RT on non-corresponding compared to corresponding trials. HD patients made more fast, impulsive errors than HC, evidenced by significantly lower accuracy on their fastest reaction time trials. The slope reduction of interference effects as reactions slowed was similar between HD and controls, indicating preserved impulse suppression.ConclusionOur results indicate that patients with HD show a greater susceptibility to act rapidly on incorrect motor impulses but preserved proficiency of top-down suppression. Further research is needed to determine how these findings relate to clinical behavioral symptoms.

Abstract The importance of metal biology in neurodegenerative diseases such as Huntingtin Disease is well documented with evidence of direct interactions between metals such as copper, zinc, iron and manganese and mutant Huntingtin pathobiology. To date, it is unclear whether these interactions are observed in humans, how this impacts other metals, and how mutant Huntington alters homeostatic mechanisms governing levels of copper, zinc, iron and manganese in cerebrospinal fluid and blood in HD patients. Plasma and cerebrospinal fluid from control, pre-manifest, manifest and late manifest HD participants were collected as part of HD-Clarity. Levels of cerebrospinal fluid and plasma copper, zinc, iron and manganese were measured as well as levels of mutant Huntingtin and neurofilament in a sub-set of cerebrospinal fluid samples. We find that elevations in cerebrospinal fluid copper, manganese and zinc levels are altered early in disease prior to alterations in canonical biomarkers of HD although these changes are not present in plasma. We also evidence that CSF iron is elevated in manifest patients. The relationships between plasma and cerebrospinal fluid metal are altered based on disease stage. These findings demonstrate that there are alterations in metal biology selectively in the CSF which occur prior to changes in known canonical biomarkers of disease. Our work indicates that there are pathological changes related to alterations in metal biology in individuals without elevations in neurofilament and mutant Huntingtin.

Abstract Impulsivity is inherent to behavioral disorders such as substance abuse and binge eating. While the role of dopamine in impulse behavior is well established, γ-aminobutyric acid (GABA) therapies have promise for the treatment of maladaptive behaviors. In Parkinson disease (PD), dopaminergic therapies can result in the development of impulsive and compulsive behaviors, and this clinical syndrome shares similar pathophysiology to that seen in addiction, substance abuse, and binge-eating disorders. We hypothesized that impulsive PD patients have a reduced thalamic GABAergic response to dopamine therapy. To test this hypothesis, we employed GABA magnetic resonance spectroscopy, D2-like receptor PET imaging, and clinical and quantitative measures of impulsivity in PD patients (n = 33), before and after dopamine agonist administration. We find a blunted thalamic GABA response to dopamine agonists in patients with elevated impulsivity (p = 0.027). These results emphasize how dopamine treatment differentially augments thalamic GABA concentrations, which may modify behavioral impulsivity.

Abstract Background Recent studies have suggested alternative cerebrospinal fluid (CSF) clearance pathways for brain parenchymal metabolic waste products. One fundamental but relatively under-explored component of these pathways is the anatomic region surrounding the superior sagittal sinus, which has been shown to have relevance to trans-arachnoid molecular passage. This so-called parasagittal dural (PSD) space may play a physiologically significant role as a distal intracranial component of the human glymphatic circuit, yet fundamental gaps persist in our knowledge of how this space changes with normal aging and intracranial bulk fluid transport. Methods We re-parameterized MRI methods to assess CSF circulation in humans using high resolution imaging of the PSD space and phase contrast measures of flow through the cerebral aqueduct to test the hypotheses that volumetric measures of PSD space (1) are directly related to CSF flow (mL/s) through the cerebral aqueduct, and (2) increase with age. Multi-modal 3-Tesla MRI was applied in healthy participants (n = 62; age range = 20–83 years) across the adult lifespan whereby phase contrast assessments of CSF flow through the aqueduct were paired with non-contrasted T 1-weighted and T 2-weighted MRI for PSD volumetry. PSD volume was extracted using a recently validated neural networks algorithm. Non-parametric regression models were applied to evaluate how PSD volume related to tissue volume and age cross-sectionally, and separately how PSD volume related to CSF flow (significance criteria: two-sided p

Objective: To identify factors associated with job satisfaction and retention, we surveyed a large cohort of clinical research coordinators (CRCs). In recent years, the clinical research coordinator has changed from a semi-permanent role to one that has a high turnover rate. The CRCs are integral to clinical research and instability in this role can cause patient stress and increase the burden on clinical teams through unnecessary delegation of resources toward hiring and retraining new talent. The cultural shift toward CRCs as a temporary position may be driven by the perspective that the role positions an individual for other health care careers, but understanding what influences low retention rates are necessary. Methods: A survey containing 13 multiple choice or open-ended and 32 Likert scale questions was distributed to previous and current CRCs using REDCap. The questionnaires were self-administered and completed over a 12-month period between October 11, 2017, and September 16, 2018. Results: A total of 85 CRCs completed the study. From the 32 potential predictors of retention, we investigated 9 significant predictors: salary, work setting, understanding the role, level of CRC, understanding protocol development, actively engaged principal investigator (PI), having a collaborative role with PI, feeling respected by PI, and having a close relationship with PI. Adequate salary, greater respect, collaboration, and engagement from the PI were significantly associated with higher retention. Surprisingly, greater workload and lack of opportunity for professional growth were not associated with retention. Conclusion: The CRCs who feel respected and engaged by the PI and are adequately compensated are more likely to have higher job satisfaction and retention.

OBJECTIVES/GOALS: To identify an electroencephalographic (EEG) signature of SOR in adults with TS METHODS/STUDY POPULATION: We will recruit 60 adults with CTD and 60 sex- and age-matched healthy controls to complete scales assessing severity of SOR (Sensory Gating Inventory, SGI), tics, and psychiatric symptoms. Subjects will then be monitored on dense-array scalp EEG during sequential auditory and tactile sensory gating paradigms, as such paradigms have been shown to correlate with self-report measures of SOR in other populations. Single-trial EEG data will be segmented into 100-ms epochs and spectrally deconvoluted into standard frequency bands (delta, theta, alpha, beta, gamma) for pre-defined regions of interest. We will conduct between-group contrasts (Wilcoxon rank-sum) of band-specific sensory gating indices and within-group correlations (Spearman rank correlations) between sensory gating indices and SGI scores. RESULTS/ANTICIPATED RESULTS: We hypothesize that, relative to controls, adults with CTD exhibit impaired sensory gating and that extent of impairment correlates with severity of SOR. 14 adults with CTD (9 men, 5 women) and 16 controls (10 men, 6 women) have completed the protocol to date. Within this sample, adults with CTD showed significantly reduced sensory gating compared to controls in frontal (CTD median 0.12 dB (interquartile range -0.15–0.70 dB); control -0.37 dB (-0.80–-0.13 dB); p = 0.01) and parietal (CTD 0.17 dB (-0.08–0.50 dB); control -0.20 dB (-0.43–0.10 dB); p = 0.01) gamma band during the 100-200 ms epoch in the tactile paradigm. No significant between-group differences were evident for the auditory paradigm. Among adults with CTD, multiple sensory gating indices significantly correlated with SGI scores. Enrollment continues. DISCUSSION/SIGNIFICANCE: Results aim to clarify the extent of sensory gating impairment in TS and identify a clinical correlate of neurophysiologic dysfunction in the disorder. Such knowledge has direct implications for identification of candidate neurophysiologic biomarkers, an express goal of the National Institutes of Health.

Abstract Objective Impulsive decision‐making is characterized by actions taken without considering consequences. Patients with Parkinson's disease (PD) who receive dopaminergic treatment, especially dopamine agonists, are at risk of developing impulsive–compulsive behaviors (ICBs). We assessed impulse‐related changes across a large heterogeneous PD population using the Barratt impulsivity scale (BIS‐11) by evaluating BIS‐11 first‐ and second‐order factors. Methods We assessed a total of 204 subjects: 93 healthy controls (HCs), and 68 ICB– and 43 ICB + PD patients who completed the BIS‐11. Using a general linear model and a least absolute shrinkage and selection operation regression, we compared BIS‐11 scores between the HC, ICB– PD, and ICB + PD groups. Results Patients with PD rated themselves as more impulsive than HCs in the BIS‐11 total score, second‐order attention domain, and first‐order attention and self‐control domains. ICB + patients recorded higher total scores as well as higher scores in the second‐order non‐planning domain and in self‐control and cognitive complexity than ICB– patients. Interpretation These results indicate that the patients with PD show particular problems with attentional control, whereas ICB + patients show a distinct problem in cognitive control and complexity. Additionally, it appears that all patients with PD are more impulsive than their age‐ and sex‐matched healthy peers. Increased impulsivity may be a result of the disease course, or attributed to dopaminergic medication use, but these results emphasize the importance of the cognitive components of impulsivity in patients with PD.

Background: Sensory over-responsivity (SOR) refers to excessively intense and/or prolonged behavioral responses to environmental stimuli typically perceived as non-aversive. SOR is prevalent in several neurodevelopmental disorders, including chronic tic disorders (CTDs) and obsessive-compulsive disorder (OCD). Few studies have examined the extent and clinical correlates of SOR across disorders, limiting insights into the phenomenon's transdiagnostic clinical and biological relevance. Such cross-disorder comparisons are of particular interest for CTDs and OCD given their frequent co-occurrence. Objective: We sought to compare the magnitude of SOR between adults with CTD and adults with OCD and to identify the clinical factors most strongly associated with SOR across these disorders. Methods: We enrolled 207 age- and sex-matched participants across four diagnostic categories: CTD without OCD (designated “CTD/OCD-”; n = 37), CTD with OCD (“CTD/OCD+”; n = 32), OCD without tic disorder (“OCD”; n = 69), and healthy controls (n = 69). Participants completed a self-report battery of rating scales assessing SOR (Sensory Gating Inventory, SGI), obsessive-compulsive symptoms (Dimensional Obsessive-Compulsive Scale, DOCS), inattention and hyperactivity (Adult ADHD Self-Report Screening Scale for DSM-5, ASRS-5), anxiety (Generalized Anxiety Disorder-7), and depression (Patient Health Questionnaire-9). CTD participants were also administered the Yale Global Tic Severity Scale (YGTSS). To examine between-group differences in SOR, we compared SGI score across all groups and between pairs of groups. To examine the relationship of SOR with other clinical factors, we performed multivariable linear regression. Results: CTD/OCD-, CTD/OCD+, and OCD participants were 86.7%, 87.6%, and 89.5%, respectively, more likely to have higher SGI total scores than healthy controls. SGI total score did not differ between CTD/OCD-, CTD/OCD+, and OCD groups. In the regression model of log-transformed SGI total score, OCD diagnosis, DOCS score, and ASRS-5 score each contributed significantly to model goodness-of-fit, whereas CTD diagnosis and YGTSS total tic score did not. Conclusion: SOR is prevalent in adults with CTD and in adults with OCD but does not significantly differ in magnitude between these disorders. Across CTD, OCD, and healthy control adult populations, SOR is independently associated with both obsessive-compulsive and ADHD symptoms, suggesting a transdiagnostic relationship between these sensory and psychiatric manifestations. Future cross-disorder, longitudinal, and translational research is needed to clarify the role and prognostic import of SOR in CTDs, OCD, and other neurodevelopmental disorders.

**Background:** Chorea is recognized as a prototypic motor feature of Huntington’s disease (HD), but its effect on health-related quality of life (HRQoL) has not been fully explored. This study describes the impact of chorea on HRQoL in patients with HD. **Objective:** To determine the impact of HD-related chorea on employment, self-care activities, activities of daily living, and health-care resource utilization (HCRU). **Methods:** Data were drawn from the Adelphi HD Disease Specific Programme, a real-world point-in-time survey of 144 neurologists and 427 patients in the United States between July and October 2017. HD patients with and without chorea were identified and examined for differences in employment status, reasons for employment changes, self-care activities, and modifications to cope with involuntary movements. Bivariate tests and inverse probability weighted regression adjustment methods were used to determine differences in outcomes between patients with and without chorea. **Results:** HD patients with (n=287) and without (n=140) chorea were identified. Patients with chorea were less likely to be employed full-time (16.7% vs 25.7%; _P_

Tics are the hallmark feature of Tourette syndrome (TS), but psychiatric and sensory symptoms are widely prevalent and increasingly recognized as core manifestations of the disorder. Accumulating evidence suggests that these psychiatric and sensory symptoms exert greater influence on quality of life (QOL) than tics themselves. However, much remains uncertain about determinants of QOL in TS due to the complexity of the clinical presentation. Here, we sought to clarify the association between health-related QOL (HRQOL) and common psychiatric and sensory symptoms in adults with TS and other chronic tic disorders. To do so, we prospectively recruited 52 patients from a tertiary care clinic to complete self-report measures assessing HRQOL (Gilles de la Tourette-Quality of Life Scale, GTS-QOL), depression (Patient Health Questionnaire-9, PHQ-9), anxiety (Generalized Anxiety Disorder Scale-7, GAD-7), obsessive-compulsive symptoms (Dimensional Obsessive-Compulsive Scale, DOCS), attention deficit hyperactivity disorder symptoms (Adult ADHD Self-Report Screening Scale for DSM-5, ASRS-V), and premonitory urge (Premonitory Urge to Tic Scale, PUTS). All participants were also administered the Yale Global Tic Severity Scale (YGTSS) to quantify tic severity. Using correlational analysis and multivariable linear regression modeling, we found that GTS-QOL score was significantly associated with scores from all other rating scales, with the exception of the PUTS. GTS-QOL was most strongly associated with PHQ-9, followed by ASRS-V, GAD-7, DOCS, and YGTSS total tic score. The regression model including these five independent variables, as well as sex, explained 79% of GTS-QOL score variance [F(6,40) = 29.6, p < 0.001]. Specific psychiatric symptoms differentially impacted physical, psychological, and cognitive HRQOL. Systematic assessment of psychiatric comorbidities is imperative for clinical care and clinical research efforts directed at improving QOL in adults with chronic tic disorders.

Abstract Introduction The orbitofrontal cortex (OFC) is involved in diverse cognitive and behavioral processes including incentive valuation, decision‐making, and reinforcement learning. Anatomic and cytoarchitectonic studies divide the OFC along both medial‐lateral and rostral‐caudal axes. OFC regions diverge in structure and function, assessed in vivo using white matter tractography and blood oxygenation level‐dependent (BOLD) MRI, respectively. However, interpretation of T2*‐weighted BOLD is limited by susceptibility artifacts in the inferior frontal lobes, with the spatial pattern of these artifacts frequently assuming the geometry of OFC organization. Here, we utilize a novel perfusion‐weighted arterial spin labeling (ASL) functional connectivity approach, which is minimally susceptibility‐weighted, to test the hypothesis that OFC topology reflects correlated temporal hemodynamic activity. Methods In healthy participants (n = 20; age = 29.5 ± 7.3), 3D ASL scans were acquired (TR/TE = 3,900/13 ms; spatial resolution = 3.8 mm isotropic). To evaluate reproducibility, follow‐up scanning on a separate day was performed on a participant subset (n = 8). ASL‐based connectivity was modeled for gray matter OFC voxels, and k‐means clustering (k = 2–8) applied to correlation statistics. Results These approaches revealed both medial‐lateral and rostral‐caudal OFC divisions, confirming our hypothesis. Longitudinal reproducibility testing revealed 84% voxel clustering agreement between sessions for the k = 2 solution. Conclusion To our knowledge, this constitutes the first in vivo cortical parcellation based on perfusion fluctuations. Our approach confirms functional OFC subdivisions predicted from anatomy using a less susceptibility‐sensitive method than the conventional approach.

Objective: To determine the impact of photophobia on persons with Progressive Supranuclear Palsy (pwPSP) by determining the functional impact of light sensitivity using methods established in migraine research. Methods: All 60 participants (pwPSP = 15, persons with Parkinson Disease (pwPD) = 15, Older adults = 30) completed a series of questionnaires designed to assess the impact of photophobia on activities of daily living. Group comparisons were controlled for multiple comparisons using a false discovery rate of 0.05. Results: Most (14/15) pwPSP participants noted that bright light hurt their eyes, and this proportion was significantly greater than pwPD (6/15; p = 0.03, corrected). PSP participants reported statistically significantly more severe light sensitivity on a subjective 0–100 scale (p = 0.003, corrected), and noted reduced time spent in both indoor and outdoor activities. Some PSP participants (n = 3) noted that they needed to wear sunglasses indoors, but most noted a reluctance to leave their house during the day due to photophobia. PwPSP indicated that they require more help from others to complete daily tasks that require them to be outside during daylight hours. Conclusions: Overall, we note a significant debility due to photophobia in PSP, and this impacts outdoor more than indoor activities. The functional disability in PSP caused by photophobia appears to cause a substantive reduction in quality of life. Future studies could consider incorporating specific metrics to evaluate measurable differences with photophobia onset and worsening severity.

Although researchers have recognized the need to better account for the heterogeneous perceptual speech characteristics among talkers with the same disease, guidance on how to best establish such dysarthria subgroups is currently lacking. Therefore, we compared subgroup decisions of two data-driven approaches based on a cohort of talkers with Huntington’s disease (HD): (1) a statistical clustering approach (STATCLUSTER) based on perceptual speech characteristic profiles and (2) an auditory free classification approach (FREECLASS) based on listeners’ similarity judgments. We determined the amount of overlap across the two subgrouping decisions and the perceptual speech characteristics driving the subgrouping decisions of each approach. The same speech samples produced by 48 talkers with HD were used for both grouping approaches. The STATCLUSTER approach had been conducted previously. The FREECLASS approach was conducted in the present study. Both approaches yielded four dysarthria subgroups, which overlapped between 50% to 78%. In both grouping approaches, overall bizarreness and speech rate characteristics accounted for the grouping decisions. In addition, voice abnormalities contributed to the grouping decisions in the FREECLASS approach. These findings suggest that apart from overall bizarreness ratings, indexing dysarthria severity, speech rate and voice characteristics may be important features to establish dysarthria subgroups in HD.

Abstract Background Neurogenic orthostatic hypotension (nOH) results from impaired vasoconstriction due to dysfunction of the autonomic nervous system and is commonly associated with Parkinson disease (PD), multiple system atrophy (MSA), and pure autonomic failure. nOH can increase the risk of falls due to symptoms that include postural lightheadedness or dizziness, presyncope, and syncope. The purpose of this study was to obtain information from patients and caregivers regarding the symptoms and burden of nOH to expand on limited knowledge regarding the impact of nOH on quality of life. Methods This author-designed survey included questions regarding nOH (e.g., frequency and impact of symptoms, management) and was conducted online by Harris Poll via distribution to individuals who agreed to participate in Harris Poll online surveys or who were members of relevant disease advocacy organizations. Eligible patients were aged ≥ 18 years with PD, MSA, or pure autonomic failure and ≥ 1 of the following: orthostatic hypotension (OH), nOH, low blood pressure upon standing, or OH/nOH symptoms. Eligible caregivers cared for such patients but were not necessarily linked to any patient participant. Results Survey responses were received from 363 patients and 128 caregivers. PD was the most frequent underlying disorder (90% of patients; 88% of individuals managed by the caregivers). Despite meeting survey diagnosis criteria, a formal diagnosis of OH or nOH was reported by only 36% of patients and 16% of caregivers. The most frequent symptoms of nOH were dizziness or lightheadedness, fatigue when standing, and difficulty walking. A negative impact on patient quality of life caused by nOH symptoms was reported by 59% of patients and 75% of caregivers. Most respondents (≥87%) reported that nOH symptoms adversely affected patients’ ability to perform everyday activities (most frequently physical activity/exercise, housework, and traveling). Falls (≥1) in the previous year due to nOH symptoms were reported by 57% of patients and 80% of caregivers. Conclusions These survey results support the premise that nOH symptoms have a substantial negative impact on patient function and quality of life. The relatively low rates of formal nOH/OH diagnosis suggest the need for heightened awareness regarding the condition and its symptom burden.

Abstract Introduction Alzheimer's and Parkinson's disease (AD and PD) are distinct disorders but share similar biomarker profiles. The regions of the default mode network are implicated in these diseases and are associated with amnestic symptoms. The role of apolipoprotein‐ε4 (APOE‐ε4), which is associated with cognitive function, is unclear in PD. Methods In this work, we evaluated cortical thickness of default mode network regions that are likely affected in both early AD and PD individuals, that is, with amnestic mild cognitive impairment. We identified the prevalence of APOE‐ε4 and evaluated its association with cortical atrophy. Results We observed significant parahippocampal atrophy and hippocampal atrophy rates in amnestic mild cognitive impairment subjects, regardless of disease origins (AD or PD). Similarly, mild cognitive impairment ε4 carriers showed significant precuneal atrophy compared with noncarriers. Discussion This work supports that converging changes to default mode network regions, especially the temporal lobe and precuneus, are shared in AD and PD.

Parkinson's disease (PD) is characterized by widespread degeneration of monoaminergic (especially dopaminergic) networks, manifesting with a number of both motor and non-motor symptoms. Regional alterations to dopamine D2/3 receptors in PD patients are documented in striatal and some extrastriatal areas, and medications that target D2/3 receptors can improve motor and non-motor symptoms. However, data regarding the combined pattern of D2/3 receptor binding in both striatal and extrastriatal regions in PD are limited. We studied 35 PD patients off-medication and 31 age- and sex-matched healthy controls (HCs) using PET imaging with [18F]fallypride, a high affinity D2/3 receptor ligand, to measure striatal and extrastriatal D2/3 nondisplaceable binding potential (BPND). PD patients completed PET imaging in the off medication state, and motor severity was concurrently assessed. Voxel-wise evaluation between groups revealed significant BPND reductions in PD patients in striatal and several extrastriatal regions, including the locus coeruleus and mesotemporal cortex. A region-of-interest (ROI) based approach quantified differences in dopamine D2/3 receptors, where reduced BPND was noted in the globus pallidus, caudate, amygdala, hippocampus, ventral midbrain, and thalamus of PD patients relative to HC subjects. Motor severity positively correlated with D2/3 receptor density in the putamen and globus pallidus. These findings support the hypothesis that abnormal D2/3 expression occurs in regions related to both the motor and non-motor symptoms of PD, including areas richly invested with noradrenergic neurons. Keywords: Parkinson's disease, Dopamine, Positron emission tomography (PET), Neurodegeneration, Fallypride