Accentuated Paralimbic and Reduced Mesolimbic D2/3-Impulsivity Associations in Parkinson's Disease.

Impulsivity is a behavioral trait that is elevated in many neuropsychiatric disorders. Parkinson's disease (PD) patients can exhibit a specific pattern of reward-seeking impulsive-compulsive behaviors (ICBs), as well as more subtle changes to generalized trait impulsivity. Prior studies in healthy controls (HCs) suggest that trait impulsivity is regulated by D2/3 autoreceptors in mesocorticolimbic circuits. While altered D2/3 binding is noted in ICB+ PD patients, there is limited prior assessment of the trait impulsivity-D2/3 relationship in PD, and no prior direct comparison with patterns in HCs. We examined 54 PD (36 M; 18 F) and 31 sex- and age-matched HC (21 M; 10 F) subjects using [18F]fallypride, a high-affinity D2/3 receptor ligand, to measure striatal and extrastriatal D2/3 nondisplaceable binding potential (BPND). Subcortical and cortical assessment exclusively used ROI or exploratory-voxelwise methods, respectively. All completed the Barratt Impulsiveness Scale, a measure of trait impulsivity. Subcortical ROI analyses indicated a negative relationship between trait impulsivity and D2/3 BPND in the ventral striatum and amygdala of HCs but not in PD. By contrast, voxelwise methods demonstrated a positive trait impulsivity-D2/3 BPND correlation in ventral frontal olfactocentric-paralimbic cortex of subjects with PD but not HCs. Subscale analysis also highlighted different aspects of impulsivity, with significant interactions between group and motor impulsivity in the ventral striatum, and attentional impulsivity in the amygdala and frontal paralimbic cortex. These results suggest that dopamine functioning in distinct regions of the mesocorticolimbic circuit influence aspects of impulsivity, with the relative importance of regional dopamine functions shifting in the neuropharmacological context of PD.SIGNIFICANCE STATEMENT The biological determinants of impulsivity have broad clinical relevance, from addiction to neurodegenerative disorders. Here, we address biomolecular distinctions in Parkinson's disease. This is the first study to evaluate a large cohort of Parkinson's disease patients and age-matched healthy controls with a measure of trait impulsivity and concurrent [18F]fallypride PET, a method that allows quantification of D2/3 receptors throughout the mesocorticolimbic network. We demonstrate widespread differences in the trait impulsivity-dopamine relationship, including (1) loss of subcortical relationships present in the healthy brain and (2) emergence of a new relationship in a limbic cortical area. This illustrates the loss of mechanisms of behavioral regulation present in the healthy brain while suggesting a potential compensatory response and target for future investigation.

IMbrave152/SKYSCRAPER-14: a Phase III study of atezolizumab, bevacizumab and tiragolumab in advanced hepatocellular carcinoma.

Atezolizumab plus bevacizumab is a standard of care, first-line therapy for advanced hepatocellular carcinoma (HCC). Myeloid and T regulatory cells are key immunosuppressive cell types within the hepatic tumor microenvironment associated with clinical resistance to atezolizumab and bevacizumab therapy for HCC and overall poor prognosis. Therapeutic targeting of TIGIT, which is highly expressed in these cells, with tiragolumab may overcome the immunosuppressive environment and improve clinical benefit, a hypothesis supported by positive efficacy signals in the Phase Ib/II MORPHEUS-Liver study. This paper describes the rationale and design of IMbrave152/SKYSCRAPER-14, a randomized, double-blind, placebo-controlled Phase III study comparing atezolizumab and bevacizumab with tiragolumab or placebo in patients with HCC and no prior systemic treatment.Clinical Trial Registration: NCT05904886 (ClinicalTrials.gov).

This research study is designed to test a new treatment combination for liver cancer, specifically for patients whose cancer cannot be removed with surgery or has spread. The treatment involves three medications: atezolizumab, bevacizumab and tiragolumab.Atezolizumab and bevacizumab are already used together as a standard treatment for liver cancer. Tiragolumab is designed to block the TIGIT receptor, which is normally involved in holding back the immune cells that would attack the tumor. Because tiragolumab may restore the immune response against the tumor, adding tiragolumab might make the treatment more effective.The study is being done worldwide and includes patients who have not received any previous systemic treatment for their advanced liver cancer. Patients participating in the study will be randomly placed into two groups. One group will receive the new combination of three medications, while the other group will receive the standard treatment of two medications plus a placebo (a treatment with no active ingredient). The main goal is to see if the new combination helps patients live longer and slows the cancer's growth compared with the standard treatment. Safety and how patients feel during the treatment are also important parts of the study.

Competitive binding of antagonistic peptides fine-tunes stomatal patterning.

During development, cells interpret complex and often conflicting signals to make optimal decisions. Plant stomata, the cellular interface between a plant and the atmosphere, develop according to positional cues, which include a family of secreted peptides called epidermal patterning factors (EPFs). How these signalling peptides orchestrate pattern formation at a molecular level remains unclear. Here we report in Arabidopsis that Stomagen (also called EPF-LIKE9) peptide, which promotes stomatal development, requires ERECTA (ER)-family receptor kinases and interferes with the inhibition of stomatal development by the EPIDERMAL PATTERNING FACTOR 2 (EPF2)-ER module. Both EPF2 and Stomagen directly bind to ER and its co-receptor TOO MANY MOUTHS. Stomagen peptide competitively replaced EPF2 binding to ER. Furthermore, application of EPF2, but not Stomagen, elicited rapid phosphorylation of downstream signalling components in vivo. Our findings demonstrate how a plant receptor agonist and antagonist define inhibitory and inductive cues to fine-tune tissue patterning on the plant epidermis.

Structural Correlates of the Sensorimotor Cerebellum in Parkinson's Disease and Essential Tremor.

BACKGROUND: Parkinson's disease (PD) and essential tremor (ET) are commonly encountered movement disorders. Pathophysiologic processes that localize to the cerebellum are described in both. There are limited studies investigating cerebellar structural changes in these conditions, largely because of inherent challenges in the efficiency of segmentation. METHODS: We applied a novel multiatlas cerebellar segmentation method to T1-weighted images in 282 PD and 111 essential tremor patients to define 26 cerebellar lobule volumes. The severity of postural and resting tremor in both populations and gait and postural instability in PD patients were defined using subscores of the UPDRS and Washington Heights-Inwood Genetic Study motor scales. These clinical measurements were related to lobule volume size. Multiple comparisons were controlled using a false discovery rate method. RESULTS: Group differences were identified between ET and PD patients, with reductions in deep cerebellar nucleus volume in ET versus reduced lobule VI volume in PD. In ET patients, lobule VIII was negatively correlated with the severity of postural tremor. In PD patients, lobule IV was positively correlated with resting tremor and total tremor severity. We observed differences in cerebellar structure that localized to sensorimotor lobules of the cerebellum. Lobule volumes appeared to differentially relate to clinical symptoms, suggesting important clinicopathologic distinctions between these conditions. These results emphasize the role of the cerebellum in tremor symptoms and should foster future clinical and pathologic investigations of the sensorimotor lobules of the cerebellum. © 2020 International Parkinson and Movement Disorder Society.

Nigrostriatal and Mesolimbic D2/3 Receptor Expression in Parkinson's Disease Patients with Compulsive Reward-Driven Behaviors.

The nigrostriatal and mesocorticolimbic dopamine networks regulate reward-driven behavior. Regional alterations to mesolimbic dopamine D2/3 receptor expression are described in drug-seeking and addiction disorders. Parkinson's disease (PD) patients are frequently prescribed D2-like dopamine agonist (DAgonist) therapy for motor symptoms, yet a proportion develop clinically significant behavioral addictions characterized by impulsive and compulsive behaviors (ICBs). Until now, changes in D2/3 receptor binding in both striatal and extrastriatal regions have not been concurrently quantified in this population. We identified 35 human PD patients (both male and female) receiving DAgonist therapy, with (n = 17) and without (n = 18) ICBs, matched for age, disease duration, disease severity, and dose of dopamine therapy. In the off-dopamine state, all completed PET imaging with [18F]fallypride, a high affinity D2-like receptor ligand that can measure striatal and extrastriatal D2/3 nondisplaceable binding potential (BPND). Striatal differences between ICB+/ICB- patients localized to the ventral striatum and putamen, where ICB+ subjects had reduced BPND In this group, self-reported severity of ICB symptoms positively correlated with midbrain D2/3 receptor BPND Group differences in regional D2/3 BPND relationships were also notable: ICB+ (but not ICB-) patients expressed positive correlations between midbrain and caudate, putamen, globus pallidus, and amygdala BPNDs. These findings support the hypothesis that compulsive behaviors in PD are associated with reduced ventral and dorsal striatal D2/3 expression, similar to changes in comparable behavioral disorders. The data also suggest that relatively preserved ventral midbrain dopaminergic projections throughout nigrostriatal and mesolimbic networks are characteristic of ICB+ patients, and may account for differential DAgonist therapeutic response.SIGNIFICANCE STATEMENT The biologic determinants of compulsive reward-based behaviors have broad clinical relevance, from addiction to neurodegenerative disorders. Here, we address biomolecular distinctions in Parkinson's disease patients with impulsive compulsive behaviors (ICBs). This is the first study to image a large cohort of ICB+ patients using positron emission tomography with [18F]fallypride, allowing quantification of D2/3 receptors throughout the mesocorticolimbic network. We demonstrate widespread differences in dopaminergic networks, including (1) D2-like receptor distinctions in the ventral striatum and putamen, and (2) a preservation of widespread dopaminergic projections emerging from the midbrain, which is associated with the severity of compulsive behaviors. This clearly illustrates the roles of D2/3 receptors and medication effects in maladaptive behaviors, and localizes them specifically to nigrostriatal and extrastriatal regions.

Quantitative magnetization transfer imaging of the human locus coeruleus.

The locus coeruleus (LC) is the major origin of norepinephrine in the central nervous system, and is subject to age-related and neurodegenerative changes, especially in disorders such as Parkinson's disease and Alzheimer's disease. Previous studies have shown that neuromelanin (NM)-sensitive MRI can be used to visualize the LC, and it is hypothesized that magnetization transfer (MT) effects are the primary source of LC contrast. The aim of this study was to characterize the MT effects in LC imaging by applying high spatial resolution quantitative MT (qMT) imaging to create parametric maps of the macromolecular content of the LC and surrounding tissues. Healthy volunteers (n = 26; sex = 17 F/9M; age = 41.0 ±â€¯19.1 years) underwent brain MRI on a 3.0 T scanner. qMT data were acquired using a 3D MT-prepared spoiled gradient echo sequence. A traditional NM scan consisting of a T1-weighted turbo spin echo sequence with MT preparation was also acquired. The pool-size ratio (PSR) was estimated for each voxel using a single-point qMT approach. The LC was semi-automatically segmented on the MT-weighted images. The MT-weighted images provided higher contrast-ratio between the LC and surrounding pontine tegmentum (PT) (0.215 ±â€¯0.031) than the reference images without MT-preparation (-0.005 ±â€¯0.026) and the traditional NM images (0.138 ±â€¯0.044). The PSR maps showed significant differences between the LC (0.090 ±â€¯0.009) and PT (0.188 ±â€¯0.025). The largest difference between the PSR values in the LC and PT was observed in the central slices, which also correspond to those with the highest contrast-ratio. These results highlight the role of MT in generating NM-related contrast in the LC, and should serve as a foundation for future studies aiming to quantify pathological changes in the LC and surrounding structures in vivo.

Ventral striatal network connectivity reflects reward learning and behavior in patients with Parkinson's disease.

A subgroup of Parkinson's disease (PD) patients treated with dopaminergic therapy develop compulsive reward-driven behaviors, which can result in life-altering morbidity. The mesocorticolimbic dopamine network guides reward-motivated behavior; however, its role in this treatment-related behavioral phenotype is incompletely understood. Here, mesocorticolimbic network function in PD patients who develop impulsive and compulsive behaviors (ICB) in response to dopamine agonists was assessed using BOLD fMRI. The tested hypothesis was that network connectivity between the ventral striatum and the limbic cortex is elevated in patients with ICB and that reward-learning proficiency reflects the extent of mesocorticolimbic network connectivity. To evaluate this hypothesis, 3.0T BOLD-fMRI was applied to measure baseline functional connectivity on and off dopamine agonist therapy in age and sex-matched PD patients with (n = 19) or without (n = 18) ICB. An incentive-based task was administered to a subset of patients (n = 20) to quantify positively or negatively reinforced learning. Whole-brain voxelwise analyses and region-of-interest-based mixed linear effects modeling were performed. Elevated ventral striatal connectivity to the anterior cingulate gyrus (P = 0.013), orbitofrontal cortex (P = 0.034), insula (P = 0.044), putamen (P = 0.014), globus pallidus (P < 0.01), and thalamus (P < 0.01) was observed in patients with ICB. A strong trend for elevated amygdala-to-midbrain connectivity was found in ICB patients on dopamine agonist. Ventral striatum-to-subgenual cingulate connectivity correlated with reward learning (P < 0.01), but not with punishment-avoidance learning. These data indicate that PD-ICB patients have elevated network connectivity in the mesocorticolimbic network. Behaviorally, proficient reward-based learning is related to this enhanced limbic and ventral striatal connectivity. Hum Brain Mapp 39:509-521, 2018. © 2017 Wiley Periodicals, Inc.

Volumetric brain MRI signatures of heart failure with preserved ejection fraction in the setting of dementia.

Heart failure with preserved ejection fraction (HFpEF) is an important, emerging risk factor for dementia, but it is not clear whether HFpEF contributes to a specific pattern of neuroanatomical changes in dementia. A major challenge to studying this is the relative paucity of datasets of patients with dementia, with/without HFpEF, and relevant neuroimaging. We sought to demonstrate the feasibility of using modern data mining tools to create and analyze clinical imaging datasets and identify the neuroanatomical signature of HFpEF-associated dementia. We leveraged the bioinformatics tools at Vanderbilt University Medical Center to identify patients with a diagnosis of dementia with and without comorbid HFpEF using the electronic health record. We identified high resolution, clinically-acquired neuroimaging data on 30 dementia patients with HFpEF (age 76.9 ± 8.12 years, 61% female) as well as 301 age- and sex-matched patients with dementia but without HFpEF to serve as comparators (age 76.2 ± 8.52 years, 60% female). We used automated image processing pipelines to parcellate the brain into 132 structures and quantify their volume. We found six regions with significant atrophy associated with HFpEF: accumbens area, amygdala, posterior insula, anterior orbital gyrus, angular gyrus, and cerebellar white matter. There were no regions with atrophy inversely associated with HFpEF. Patients with dementia and HFpEF have a distinct neuroimaging signature compared to patients with dementia only. Five of the six regions identified in are in the temporo-parietal region of the brain. Future studies should investigate mechanisms of injury associated with cerebrovascular disease leading to subsequent brain atrophy.

CONTACT-01: A Randomized Phase III Trial of Atezolizumab + Cabozantinib Versus Docetaxel for Metastatic Non-Small Cell Lung Cancer After a Checkpoint Inhibitor and Chemotherapy.

PURPOSE: Although checkpoint inhibitors have improved first-line treatment for non-small cell lung cancer (NSCLC), a therapeutic need remains for patients whose disease does not respond or who experience disease progression after anti-PD-L1/PD-1 immunotherapy. CONTACT-01 (ClinicalTrials.gov identifier: NCT04471428) evaluated atezolizumab plus cabozantinib versus docetaxel in patients with metastatic NSCLC who developed disease progression after concurrent or sequential treatment with anti-PD-L1/PD-1 and platinum-containing chemotherapy. METHODS: This multicenter, open-label, phase III trial randomly assigned patients 1:1 to atezolizumab 1,200 mg intravenously once every 3 weeks (q3w) plus cabozantinib 40 mg orally once daily or docetaxel 75 mg/m2 intravenously once every 3 weeks. The primary end point was overall survival (OS). RESULTS: One hundred eighty-six patients were assigned atezolizumab plus cabozantinib, and 180 docetaxel. Minimum OS follow-up was 10.9 months. Median OS was 10.7 months (95% CI, 8.8 to 12.3) with atezolizumab plus cabozantinib and 10.5 months (95% CI, 8.6 to 13.0) with docetaxel (stratified hazard ratio [HR], 0.88 [95% CI, 0.68 to 1.16]; P = .3668). Median progression-free survival was 4.6 months (95% CI, 4.1 to 5.6) and 4.0 months (95% CI, 3.1 to 4.4), respectively (stratified HR, 0.74 [95% CI, 0.59 to 0.92]). Serious adverse events (AEs) occurred in 71 (38.4%) patients receiving atezolizumab plus cabozantinib and 58 (34.7%) receiving docetaxel. Grade 3/4 treatment-related AEs occurred in 73 (39.5%) patients receiving atezolizumab plus cabozantinib and 58 (34.7%) receiving docetaxel. Grade 5 AEs occurred in 14 (7.6%) and 10 (6.0%) patients in the atezolizumab plus cabozantinib and docetaxel arms, respectively (treatment-related in four [2.2%] and one [0.6%], respectively). CONCLUSION: Atezolizumab plus cabozantinib after disease progression following anti-PD-L1/PD-1 immunotherapy and platinum-containing chemotherapy for metastatic NSCLC did not improve OS compared with docetaxel. Safety was consistent with known profiles of these agents.

Overcome the Limitation of Phenome-Wide Association Studies (PheWAS): Extension of PheWAS to Efficient and Robust Large-Scale ICD Codes Analysis.

The Phenome-wide association studies (PheWAS) have become widely used for efficient, high-throughput evaluation of relationship between a genetic factor and a large number of disease phenotypes, typically extracted from a DNA biobank linked with electronic medical records (EMR). Phecodes, billing code-derived disease case-control status, are usually used as outcome variables in PheWAS and logistic regression has been the standard choice of analysis method. Since the clinical diagnoses in EMR are often inaccurate with errors which can lead to biases in the odds ratio estimates, much effort has been put to accurately define the cases and controls to ensure an accurate analysis. Specifically in order to correctly classify controls in the population, an exclusion criteria list for each Phecode was manually compiled to obtain unbiased odds ratios. However, the accuracy of the list cannot be guaranteed without extensive data curation process. The costly curation process limits the efficiency of large-scale analyses that take full advantage of all structured phenotypic information available in EMR. Here, we proposed to estimate relative risks (RR) instead. We first demonstrated the desired nature of RR that overcomes the inaccuracy in the controls via theoretical formula. With simulation and real data application, we further confirmed that RR is unbiased without compiling exclusion criteria lists. With RR as estimates, we are able to efficiently extend PheWAS to a larger-scale, phenome construction agnostic analysis of phenotypes, using ICD 9/10 codes, which preserve much more disease-related clinical information than Phecodes.

Symptoms of Medication Withdrawal in Parkinson's Disease: Considerations for Informed Consent in Patient-Oriented Research.

INTRODUCTION: Dopamine medication withdrawal in Parkinson's disease (PD) is commonly employed in clinical practice and can be required for participation in research studies. When asked to withdraw from medications, participants often enquire as to what symptoms they should expect. OBJECTIVES: This study sought to improve the informed consent process by identifying patient-reported symptoms when dopamine treatment is withheld. We also sought to provide clinical guidance regarding the extent of these symptoms and consider participant willingness to undergo these assessments. METHODS: Participants were recruited from community-based PD programs and support groups in Nashville, Tennessee, USA. A patient-based questionnaire determined the frequency and severity of motor and nonmotor symptoms. The questionnaire also assessed whether patients would be willing to abstain from medication at a future date and under what circumstances. RESULTS: A total of 31/90 participants reported willingness to withdraw from dopaminergic medications for clinical or research purposes. Tremor, walking, and balance were the most common motor symptoms that worsened during this time. Sleep dysfunction, constipation, and tremor were noted as the most severe symptoms. Of note, 10% of participants indicated that they would not be willing to go off medications again, suggesting that a minority of patients find this to be most discomforting. When prompted for a reason why participants would be willing to come off of their medications again, "for clinical purposes" was selected the most. CONCLUSIONS: Study teams should list these symptoms in the applications to their institutional review board and in the informed consent to provide guidance for participants.

Clinical implications of photophobia in progressive supranuclear palsy.

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.

Empowering the Clinical Research Coordinator in Academic Medical Centers.

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.

Diffusion along perivascular spaces reveals evidence supportive of glymphatic function impairment in Parkinson disease.

BACKGROUND: Reduced diffusion along perivascular spaces in adults with Alzheimer's-disease-related-dementias has been reported and attributed to reduced glymphatic function. OBJECTIVES: To apply quantitative measures of diffusion along, and orthogonal to, perivascular spaces in a cohort of older adults with and without clinical symptoms of alpha-synuclein related neurodegeneration. METHODS: 181 adults with Parkinson disease (PD) or essential tremor (ET) additionally sub-classified by the presence of cognitive impairment underwent 3 T MRI. Diffusion-tensor-imaging (spatial resolution = 2x2x2 mm; b-value = 1000 s/mm2; directions = 33) measures of diffusion (mm2/s) parallel and orthogonal to perivascular spaces at the level of the medullary veins, and the ratio of these measures (ALPS-index), were calculated. Regions were identified by a board-certified neuroradiologist from T1-weighted and T2-weighted MRI. Evaluations of motor impairment and mild cognitive impairment (MCI) were interpreted by a board-certified neurologist and neuropsychologist, respectively. Multiple regression with false discovery rate correction was applied to understand how diffusion metrics related to (i) disease category (PD vs. ET), (ii) cognition (MCI status), and (iii) white matter disease severity from the Fazekas score. RESULTS: The ALPS-index was reduced in PD compared to ET participants (p = 0.037). No association between the ALPS-index and MCI status, but an inverse association between the ALPS-index and Fazekas score (p = 0.002), was observed. The ALPS-index was inversely associated with age (p = 0.007). CONCLUSION: Diffusion aberrations near perivascular spaces are evident in patients with alpha-synuclein related neurodegenerative disorders, and are related to age and white matter disease severity.

Healthcare Delivery and Huntington's Disease During the Time of COVID-19.

BACKGROUND: Safer-at-home orders during the COVID-19 pandemic altered the structure of clinical care for Huntington's disease (HD) patients. This shift provided an opportunity to identify limitations in the current healthcare infrastructure and how these may impact the health and well-being of persons with HD. OBJECTIVE: The study objectives were to assess the feasibility of remote healthcare delivery in HD patients, to identify socioeconomic factors which may explain differences in feasibility and to evaluate the impact of safer-at-home orders on HD patient stress levels. METHODS: This observational study of a clinical HD population during the 'safer-at-home' orders asked patients or caregivers about their current access to healthcare resources and patient stress levels. A chart review allowed for an assessment of socioeconomic status and characterization of HD severity. RESULTS: Two-hundred and twelve HD patients were contacted with 156 completing the survey. During safer-at-home orders, the majority of HD patients were able to obtain medications and see a physician; however, 25% of patients would not commit to regular telehealth visits, and less than 50% utilized an online healthcare platform. We found that 37% of participants were divorced/single, 39% had less than a high school diploma, and nearly 20% were uninsured or on low-income health insurance. Patient stress levels correlated with disease burden. CONCLUSION: A significant portion of HD participants were not willing to participate in telehealth services. Potential explanations for these limitations may include socioeconomic barriers and caregiving structure. These observations illustrate areas for clinical care improvement to address healthcare disparities in the HD community.

Self-reported rates of impulsivity in Parkinson's Disease.

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.

Motor speech patterns in Huntington disease.

OBJECTIVE: Dysarthric speech of persons with Huntington disease (HD) is typically described as hyperkinetic; however, studies suggest that dysarthria can vary and resemble patterns in other neurologic conditions. To test the hypothesis that distinct motor speech subgroups can be identified within a larger cohort of patients with HD, we performed a cluster analysis on speech perceptual characteristics of patient audio recordings. METHODS: Audio recordings of 48 patients with mild to moderate dysarthria due to HD were presented to 6 trained raters. Raters provided scores for various speech features (e.g., voice, articulation, prosody) of audio recordings using the classic Mayo Clinic dysarthria rating scale. Scores were submitted to an unsupervised k-means cluster analysis to determine the most salient speech features of subgroups based on motor speech patterns. RESULTS: Four unique subgroups emerged from the cohort of patients with HD. Subgroup 1 was characterized by an abnormally fast speaking rate among other unique speech features, whereas subgroups 2 and 3 were defined by an abnormally slow speaking rate. Salient speech features for subgroup 2 overlapped with subgroup 3; however, the severity of dysarthria differed. Subgroup 4 was characterized by mild deviations of speech features with typical speech rate. Length of CAG repeats, Unified Huntington's Disease Rating Scale total motor score, and percent intelligibility were significantly different for pairwise comparisons of subgroups. CONCLUSION: This study supports the existence of distinct presentations of dysarthria in patients with HD, which may be due to divergent pathologic processes. The findings are discussed in relation to previous literature and clinical implications.

Dopamine effects on frontal cortical blood flow and motor inhibition in Parkinson's disease.

Parkinson's disease (PD) is characterized by dysfunction in frontal cortical and striatal networks that regulate action control. We investigated the pharmacological effect of dopamine agonist replacement therapy on frontal cortical activity and motor inhibition. Using Arterial Spin Labeling MRI, we examined 26 PD patients in the off- and on-dopamine agonist medication states to assess the effect of dopamine agonists on frontal cortical regional cerebral blood flow. Motor inhibition was measured by the Simon task in both medication states. We applied the dual process activation suppression model to dissociate fast response impulses from motor inhibition of incorrect responses. General linear regression model analyses determined the medication effect on regional cerebral blood flow and motor inhibition, and the relationship between regional cerebral blood flow and motor inhibitory proficiency. We show that dopamine agonist administration increases frontal cerebral blood flow, particularly in the pre-supplementary motor area (pre-SMA) and the dorsolateral prefrontal cortex (DLPFC). Higher regional blood flow in the pre-SMA, DLPFC and motor cortex was associated with better inhibitory control, suggesting that treatments which improve frontal cortical activity could ameliorate motor inhibition deficiency in PD patients.

White matter differences between essential tremor and Parkinson disease.

OBJECTIVE: To assess white matter integrity in patients with essential tremor (ET) and Parkinson disease (PD) with moderate to severe motor impairment. METHODS: Sedated participants with ET (n = 57) or PD (n = 99) underwent diffusion tensor imaging (DTI) and fractional anisotropy, mean diffusivity, axial diffusivity, and radial diffusivity values were computed. White matter tracts were defined using 3 well-described atlases. To determine candidate white matter regions that differ between ET and PD groups, a bootstrapping analysis was applied using the least absolute shrinkage and selection operator. Linear regression was applied to assess magnitude and direction of differences in DTI metrics between ET and PD populations in the candidate regions. RESULTS: Fractional anisotropy values that differentiate ET from PD localize primarily to thalamic and visual-related pathways, while diffusivity differences localized to the cerebellar peduncles. Patients with ET exhibited lower fractional anisotropy values than patients with PD in the lateral geniculate body (p < 0.01), sagittal stratum (p = 0.01), forceps major (p = 0.02), pontine crossing tract (p = 0.03), and retrolenticular internal capsule (p = 0.04). Patients with ET exhibited greater radial diffusivity values than patients with PD in the superior cerebellar peduncle (p < 0.01), middle cerebellar peduncle (p = 0.05), and inferior cerebellar peduncle (p = 0.05). CONCLUSIONS: Regionally, distinctive white matter microstructural values in patients with ET localize to the cerebellar peduncles and thalamo-cortical visual pathways. These findings complement recent functional imaging studies in ET but also extend our understanding of putative physiologic features that account for distinctions between ET and PD.