Characterizing coma in large vessel occlusion stroke

BACKGROUND

Coma is an unresponsive state of disordered consciousness characterized by impaired arousal and awareness. The epidemiology and pathophysiology of coma in ischemic stroke has been underexplored. We sought to characterize the incidence and clinical features of coma as a presentation of large vessel occlusion (LVO) stroke.

METHODS

Individuals who presented with LVO were retrospectively identified from July 2018 to December 2020. Coma was defined as an unresponsive state of impaired arousal and awareness, operationalized as a score of 3 on NIHSS item 1a.

RESULTS

28/637 (4.4%) patients with LVO stroke were identified as presenting with coma. The median NIHSS was 32 (IQR 29-34) for those with coma versus 11 (5-18) for those without (p < 0.0001). In coma, occlusion locations included basilar (13), vertebral (2), internal carotid (5), and middle cerebral (9) arteries. 8/28 were treated with endovascular thrombectomy (EVT), and 20/28 died during the admission. 65% of patients not treated with EVT had delayed presentations or large established infarcts. In models accounting for pre-stroke mRS, basilar occlusion location, intravenous thrombolysis, and EVT, coma independently increased the odds of transitioning to comfort care during admission (aOR 6.75; 95% CI 2.87,15.84; p < 0.001) and decreased the odds of 90-day mRS 0-2 (aOR 0.12; 95% CI 0.03,0.55; p = 0.007).

CONCLUSIONS

It is not uncommon for patients with LVO to present with coma, and delayed recognition of LVO can lead to poor outcomes, emphasizing the need for maintaining a high index of suspicion. While more commonly thought to result from posterior LVO, coma in our cohort was similarly likely to result from anterior LVO. Efforts to improve early diagnosis and care of patients with LVO presenting with coma are crucial.

Does Vestibular Motion Perception Correlate with Axonal Pathways Stimulated by Subthalamic Deep Brain Stimulation in Parkinson's Disease?

Perception of our linear motion - heading - is critical for postural control, gait, and locomotion, and it is impaired in Parkinson's disease (PD). Deep brain stimulation (DBS) has variable effects on vestibular heading perception, depending on the location of the electrodes within the subthalamic nucleus (STN). Here, we aimed to find the anatomical correlates of heading perception in PD. Fourteen PD participants with bilateral STN DBS performed a two-alternative forced-choice discrimination task where a motion platform delivered translational forward movements with a heading angle varying between 0 and 30° to the left or to the right with respect to the straight-ahead direction. Using psychometric curves, we derived the heading discrimination threshold angle of each patient from the response data. We created patient-specific DBS models and calculated the percentages of stimulated axonal pathways that are anatomically adjacent to the STN and known to play a major role in vestibular information processing. We performed correlation analyses to investigate the extent of these white matter tracts' involvement in heading perception. Significant positive correlations were identified between improved heading discrimination for rightward heading and the percentage of activated streamlines of the contralateral hyperdirect, pallido-subthalamic, and subthalamo-pallidal pathways. The hyperdirect pathways are thought to provide top-down control over STN connections to the cerebellum. In addition, STN may also antidromically activate collaterals of hyperdirect pathway that projects to the precerebellar pontine nuclei. In select cases, there was strong activation of the cerebello-thalamic projections, but it was not consistently present in all participants. Large volumetric overlap between the volume of tissue activation and the STN in the left hemisphere positively impacted rightward heading perception. Altogether, the results suggest heavy involvement of basal ganglia cerebellar network in STN-induced modulation of vestibular heading perception in PD.

Caregiver Burden in Parkinson Disease: A Scoping Review of the Literature from 2017-2022

Caregiver burden is a term that refers to the adverse effect of caregiving on the physical, emotional, social, spiritual, and financial well-being of the caregiver. Caregiver burden is associated with providing care to an individual with a chronic illness or disability, and the unique symptoms of Parkinson disease (PD) can amplify a patient's needs and reliance on others, leading to adverse outcomes for patients and their caregivers. In this scoping review of the literature from January 2017 through April 2022 that included 114 studies, we provide an updated, evidence-based summary of patient and caregiver-related factors that contribute to caregiver burden in PD. We also describe the impact of caregiver stress and burden on caregivers based on qualitative research studies and review recent interventions to mitigate burden. By providing clinical updates for practitioners, this review is designed to improve recognition of caregiver burden in the post-pandemic era and foster the development of targeted interventions to reduce caregiver burden in PD.

Impact of the COVID-19 Pandemic on Inpatient Utilization for Acute Neurologic Disease

Background and Objective: The initial months of the Corona Virus 2019 (COVID-19) pandemic resulted in decreased hospitalizations. We aimed to describe differences in hospitalizations and related procedures across neurologic disease. Methods: In our retrospective observational study using the California State Inpatient Database and state-wide population-level estimates, we calculated neurologic hospitalization rates for a control period from January 2019 to February 2020 and a COVID-19 pandemic period from March to December 2020. We calculated incident rate ratios (IRR) for neurologic hospitalizations using negative binomial regression and compared relevant procedure rates over time. Results: Population-based neurologic hospitalization rates were 29.1 per 100,000 (95% CI 26.9-31.3) in April 2020 compared to 43.6 per 100,000 (95% CI 40.4-46.7) in January 2020. Overall, the pandemic period had 13% lower incidence of neurologic hospitalizations per month (IRR 0.87, 95% CI 0.86-0.89). The smallest decreases were in neurotrauma (IRR 0.92, 95% CI 0.89-0.95) and neuro-oncologic cases (IRR 0.93, 95% CI 0.87-0.99). Headache admissions experienced the greatest decline (IRR 0.62, 95% CI 0.58-0.66). For ischemic stroke, greater rates of endovascular thrombectomy (5.6% vs 5.0%; P < .001) were observed in the pandemic. Among all neurologic disease, greater rates of gastrostomy (4.0% vs 3.5%; P < .001), intubation/mechanical ventilation (14.3% vs 12.9%, P < .001), and tracheostomy (1.4 vs 1.2%; P < .001) were observed during the pandemic. Conclusions: During the first months of the COVID-19 pandemic there were fewer hospitalizations to varying degrees for all neurologic diagnoses. Rates of procedures indicating severe disease increased. Further study is needed to determine the impact on triage, patient outcomes, and cost consequences.

Use of Natural Language Processing to Identify Sexual and Reproductive Health Information in Clinical Text

OBJECTIVES

This study aimed to enable clinical researchers without expertise in natural language processing (NLP) to extract and analyze information about sexual and reproductive health (SRH), or other sensitive health topics, from large sets of clinical notes.

METHODS

(1) We retrieved text from the electronic health record as individual notes. (2) We segmented notes into sentences using one of scispaCy's NLP toolkits. (3) We exported sentences to the labeling application Watchful and annotated subsets of these as relevant or irrelevant to various SRH categories by applying a combination of regular expressions and manual annotation. (4) The labeled sentences served as training data to create machine learning models for classifying text; specifically, we used spaCy's default text classification ensemble, comprising a bag-of-words model and a neural network with attention. (5) We applied each model to unlabeled sentences to identify additional references to SRH with novel relevant vocabulary. We used this information and repeated steps 3 to 5 iteratively until the models identified no new relevant sentences for each topic. Finally, we aggregated the labeled data for analysis.

RESULTS

This methodology was applied to 3,663 Child Neurology notes for 971 female patients. Our search focused on six SRH categories. We validated the approach using two subject matter experts, who independently labeled a sample of 400 sentences. Cohen's kappa values were calculated for each category between the reviewers (menstruation: 1, sexual activity: 0.9499, contraception: 0.9887, folic acid: 1, teratogens: 0.8864, pregnancy: 0.9499). After removing the sentences on which reviewers did not agree, we compared the reviewers' labels to those produced via our methodology, again using Cohen's kappa (menstruation: 1, sexual activity: 1, contraception: 0.9885, folic acid: 1, teratogens: 0.9841, pregnancy: 0.9871).

CONCLUSION

Our methodology is reproducible, enables analysis of large amounts of text, and has produced results that are highly comparable to subject matter expert manual review.

Proprioceptive Modulation of Pallidal Physiology in Cervical Dystonia

BACKGROUND

There is a growing body of evidence suggesting that botulinum toxin can alter proprioceptive feedback and modulate the muscle-spindle output for the treatment of dystonia. However, the mechanism for this modulation remains unclear.

METHODS

We conducted a study involving 17 patients with cervical dystonia (CD), seven of whom had prominent CD and 10 with generalized dystonia (GD) along with CD. We investigated the effects of neck vibration, a form of proprioceptive modulation, on spontaneous single-neuron responses and local field potentials (LFPs) recorded from the globus pallidum externus (GPe) and internus (GPi).

RESULTS

Our findings demonstrated that neck vibration notably increased the regularity of neck-sensitive GPi neurons in focal CD patients. Additionally, in patients with GD and CD, the vibration enhanced the firing regularity of non-neck-sensitive neurons. These effects on single-unit activity were also mirrored in ensemble responses measured through LFPs. Notably, the LFP modulation was particularly pronounced in areas populated with burst neurons compared to pause or tonic cells.

CONCLUSION

The results from our study emphasize the significance of burst neurons in the pathogenesis of dystonia and in the efficacy of proprioceptive modulation for its treatment. Moreover, we observed that the effects of vibration on focal CD were prominent in the α band LFP, indicating modulation of pallido-cerebellar connectivity. Moreover, the pallidal effects of vibration in GD with CD involved modulation of cerebro-pallidal θ band connectivity. Our analysis provides insight into how vibration-induced changes in pallidal activity are integrated into the downstream motor circuit. © 2023 International Parkinson and Movement Disorder Society.

Unraveling the Twist: Spatial Navigational Challenges in Cervical Dystonia

BACKGROUND

Cervical dystonia (CD) is an intricate neurological condition with motor and nonmotor symptoms. These include disruptions in visual perception, self-orientation, visual working memory, and vestibular functions. However, the specific impact of CD on perceiving self-motion direction, especially with isolated visual or vestibular stimuli, remains largely unexplored.

OBJECTIVE

This study aimed to examine the effects of CD on linear motion perception, hypothesizing impaired heading discrimination in both vestibular and visual tasks, and that such deficits correlate with the disease severity.

METHODS

We employed a cutting-edge motion platform to precisely control whole-body linear motion. Through repeated two-alternative forced-choice tasks, we assessed vestibular heading direction discrimination. Participants observed dynamic star clouds in immersive virtual reality and indicated their perceived self-motion direction, evaluating visual heading direction discrimination. Sensitivity to direction variations and response accuracy errors were analyzed using robust Gaussian cumulative distribution psychometric functions.

RESULTS

Heading perception is impaired in individuals with CD, particularly evident in vestibular heading discrimination. CD severity correlated with elevated thresholds for both vestibular and visual heading discrimination. Surprisingly, lateralized CD did not introduce bias in either system, suggesting widespread disruption over localized effects.

CONCLUSIONS

Contrary to previous beliefs, our findings challenge the idea that CD-related heading discrimination issues mainly arise from peripheral vestibular effects. Instead, abnormal proprioceptive input from dystonic neck muscles introduces noise into the central mechanism integrating visual, vestibular, and proprioceptive signals. These insights into spatial navigation deficits have implications for future CD research. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.

In humans, striato-pallido-thalamic projections are largely segregated by their origin in either the striosome-like or matrix-like compartments

Cortico-striato-thalamo-cortical (CSTC) loops are fundamental organizing units in mammalian brains. CSTCs process limbic, associative, and sensorimotor information in largely separated but interacting networks. CTSC loops pass through paired striatal compartments, striosome (aka patch) and matrix, segregated pools of medium spiny projection neurons with distinct embryologic origins, cortical/subcortical structural connectivity, susceptibility to injury, and roles in behaviors and diseases. Similarly, striatal dopamine modulates activity in striosome and matrix in opposite directions. Routing CSTCs through one compartment may be an anatomical basis for regulating discrete functions. We used differential structural connectivity, identified through probabilistic diffusion tractography, to distinguish the striatal compartments (striosome-like and matrix-like voxels) in living humans. We then mapped compartment-specific projections and quantified structural connectivity between each striatal compartment, the globus pallidus interna (GPi), and 20 thalamic nuclei in 221 healthy adults. We found that striosome-originating and matrix-originating streamlines were segregated within the GPi: striosome-like connectivity was significantly more rostral, ventral, and medial. Striato-pallido-thalamic streamline bundles that were seeded from striosome-like and matrix-like voxels transited spatially distinct portions of the white matter. Matrix-like streamlines were 5.7-fold more likely to reach the GPi, replicating animal tract-tracing studies. Striosome-like connectivity dominated in six thalamic nuclei (anteroventral, central lateral, laterodorsal, lateral posterior, mediodorsal-medial, and medial geniculate). Matrix-like connectivity dominated in seven thalamic nuclei (centromedian, parafascicular, pulvinar-anterior, pulvinar-lateral, ventral lateral-anterior, ventral lateral-posterior, ventral posterolateral). Though we mapped all thalamic nuclei independently, functionally-related nuclei were matched for compartment-level bias. We validated these results with prior thalamostriate tract tracing studies in non-human primates and other species; where reliable data was available, all agreed with our measures of structural connectivity. Matrix-like connectivity was lateralized (left > right hemisphere) in 18 thalamic nuclei, independent of handedness, diffusion protocol, sex, or whether the nucleus was striosome-dominated or matrix-dominated. Compartment-specific biases in striato-pallido-thalamic structural connectivity suggest that routing CSTC loops through striosome-like or matrix-like voxels is a fundamental mechanism for organizing and regulating brain networks. Our MRI-based assessments of striato-thalamic connectivity in humans match and extend the results of prior tract tracing studies in animals. Compartment-level characterization may improve localization of human neuropathologies and improve neurosurgical targeting in the GPi and thalamus.

Unique characteristics of end-of-life hospitalizations in Parkinson disease

Introduction

Persons with Parkinson disease (PD) are hospitalized at higher rates, have longer lengths of stay, and are more likely to die in the hospital than age-matched peers. Although prior studies have compared inpatient outcomes between persons with and without PD, little is known about inpatient outcomes across the PD trajectory, or whether hospitalizations occurring in the last 6 months of life differ from earlier hospitalizations.

Methods

This cross-sectional study compared Medicare Part A and B beneficiaries aged 65 and older with a qualifying PD diagnosis who were hospitalized in 2017: decedents who died between 7/1/2017 and 12/31/2017 from all causes and were hospitalized at least once in their last 6 months of life, and non-decedents who were hospitalized between 1/1/2017 and 6/30/2017 and lived 6 or more months after discharge. End-of-life (EoL) hospitalizations were defined as those occurring in the last 6 months of life. Descriptive analyses compared patient-level variables (e.g., demographics, comorbidities, treatment intensity) and encounter-level variables (e.g., length of stay, total charges) between groups. Multivariable logistic regression models also compared rates of intensive care unit (ICU) admission and 30-day readmission between hospitalized decedents and hospitalized non-decedents, adjusting for age, sex, race/ethnicity, rural residence, and Charlson Comorbidity Index Score.

Results

Of 26,492 Medicare decedents with PD, 16,187 (61.1%) were hospitalized in their last 6 months of life. Of 347,512 non-decedents with PD, 62,851 (18.1%) were hospitalized in a 6-month period. Hospitalized decedents were slightly older than hospitalized non-decedents (82.3 [SD 7.40] vs. 79.5 [SD 7.54] years) and had significantly more comorbidities. Compared to non-EoL hospitalizations, EoL hospitalizations were slightly longer (5 [IQR 3-9] vs. 4 [IQR 3-7] days) and more expensive based on total charges per admission ($36,323 [IQR 20,091-69,048] vs. $32,309 [IQR 18,789-57,756]). In covariate-adjusted regression models using hospitalized non-decedents as the reference group, hospitalized decedents were more likely to experience an ICU admission (AOR 2.36; CI 2.28-2.45) and 30-day readmission (AOR 2.43; CI 2.34-2.54).

Discussion

Hospitalizations occurring in the last 6 months of life among persons with PD in the United States are longer, more costly, and more resource intensive than earlier hospitalizations and may stem from medical comorbidities. Once hospitalized, ICU admission and 30-day readmission may aid in prognostication and serve as markers of transition to the EoL period.

The effects of closed-loop auditory stimulation on sleep oscillatory dynamics in relation to motor procedural memory consolidation

STUDY OBJECTIVES

Healthy aging and many disorders show reduced sleep-dependent memory consolidation and corresponding alterations in non-rapid eye movement sleep oscillations. Yet sleep physiology remains a relatively neglected target for improving memory. We evaluated the effects of closed-loop auditory stimulation during sleep (CLASS) on slow oscillations (SOs), sleep spindles, and their coupling, all in relation to motor procedural memory consolidation.

METHODS

Twenty healthy young adults had two afternoon naps: one with auditory stimulation during SO upstates and another with no stimulation. Twelve returned for a third nap with stimulation at variable times in relation to SO upstates. In all sessions, participants trained on the motor sequence task prior to napping and were tested afterward.

RESULTS

Relative to epochs with no stimulation, upstate stimuli disrupted sleep and evoked SOs, spindles, and SO-coupled spindles. Stimuli that successfully evoked oscillations were delivered closer to the peak of the SO upstate and when spindle power was lower than stimuli that failed to evoke oscillations. Across conditions, participants showed similar significant post-nap performance improvement that correlated with the density of SO-coupled spindles.

CONCLUSIONS

Despite its strong effects on sleep physiology, CLASS failed to enhance motor procedural memory. Our findings suggest methods to overcome this failure, including better sound calibration to preserve sleep continuity and the use of real-time predictive algorithms to more precisely target SO upstates and to avoid disrupting endogenous SO-coupled spindles and their mnemonic function. They motivate continued development of CLASS as an intervention to manipulate sleep oscillatory dynamics and improve memory.

Can immunological imprinting drive neurological dysfunction in long COVID?

This scientific commentary refers to ‘Neurologic sequelae of COVID-19 are determined by immunologic imprinting from previous coronaviruses’ by Spatola et al. (https://doi.org/10.1093/brain/awad155).

Neurologic sequelae of COVID-19 are determined by immunologic imprinting from previous coronaviruses

Coronavirus disease 2019 (COVID-19), which is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), remains a global public health emergency. Although SARS-CoV-2 is primarily a respiratory pathogen, extra-respiratory organs, including the CNS, can also be affected. Neurologic symptoms have been observed not only during acute SARS-CoV-2 infection, but also at distance from respiratory disease, also known as long-COVID or neurological post-acute sequelae of COVID-19 (neuroPASC). The pathogenesis of neuroPASC is not well understood, but hypotheses include SARS-CoV-2-induced immune dysfunctions, hormonal dysregulations and persistence of SARS-CoV-2 reservoirs. In this prospective cohort study, we used a high throughput systems serology approach to dissect the humoral response to SARS-CoV-2 (and other common coronaviruses: 229E, HKU1, NL63 and OC43) in the serum and CSF from 112 infected individuals who developed (n = 18) or did not develop (n = 94) neuroPASC. Unique SARS-CoV-2 humoral profiles were observed in the CSF of neuroPASC compared with serum responses. All antibody isotypes (IgG, IgM, IgA) and subclasses (IgA1-2, IgG1-4) were detected in serum, whereas CSF was characterized by focused IgG1 (and absence of IgM). These data argue in favour of compartmentalized brain-specific responses against SARS-CoV-2 through selective transfer of antibodies from the serum to the CSF across the blood-brain barrier, rather than intrathecal synthesis, where more diversity in antibody classes/subclasses would be expected. Compared to individuals who did not develop post-acute complications following infection, individuals with neuroPASC had similar demographic features (median age 65 versus 66.5 years, respectively, P = 0.55; females 33% versus 44%, P = 0.52) but exhibited attenuated systemic antibody responses against SARS-CoV-2, characterized by decreased capacity to activate antibody-dependent complement deposition (ADCD), NK cell activation (ADNKA) and to bind Fcγ receptors. However, surprisingly, neuroPASC individuals showed significantly expanded antibody responses to other common coronaviruses, including 229E, HKU1, NL63 and OC43. This biased humoral activation across coronaviruses was particularly enriched in neuroPASC individuals with poor outcome, suggesting an 'original antigenic sin' (or immunologic imprinting), where pre-existing immune responses against related viruses shape the response to the current infection, as a key prognostic marker of neuroPASC disease. Overall, these findings point to a pathogenic role for compromised anti-SARS-CoV-2 responses in the CSF, likely resulting in incomplete virus clearance from the brain and persistent neuroinflammation, in the development of post-acute neurologic complications of SARS-CoV-2 infection.

Utilizing machine learning and lipidomics to distinguish primary lateral sclerosis from amyotrophic lateral sclerosis

INTRODUCTION/AIMS

There are currently no imaging or blood diagnostic biomarkers that can differentiate amyotrophic lateral sclerosis (ALS) from primary lateral sclerosis (PLS) patients early in their disease courses. Our objective is to examine whether patients with PLS can be differentiated from ALS reliably by using plasma lipidome profile and supervised machine learning.

METHODS

40 ALS and 28 PLS patients derived from the Multicenter Cohort study of Oxidative Stress (COSMOS) and 28 healthy control volunteers (CTR) were included. ALS, PLS, and CTR were matched by age and sex. Plasma samples were obtained after overnight fasting. Lipids were extracted from the plasma samples and analyzed using liquid chromatography/mass spectrometry to obtain relative concentrations of 392 lipid species. The lipid data were partitioned into training and testing datasets randomly. An elastic net algorithm was trained using cross-validation to classify PLS vs ALS and PLS vs CTR. Final accuracy was evaluated in the testing dataset.

RESULTS

The elastic net model trained with labeled PLS and ALS training lipid dataset demonstrated accuracy (number classified correctly/total number), sensitivity, and specificity of 100% in classifying PLS vs ALS in the unlabeled testing lipid dataset. Similarly, the elastic net model trained with labeled PLS and CTR training lipid datasets demonstrated accuracy, sensitivity, and specificity of 88% in classifying PLS vs CTR in the unlabeled testing lipid dataset.

DISCUSSION

Our study suggests PLS patients can be accurately distinguished from ALS and CTR by combining lipidome profile and supervised machine learning without clinical information.

A qualitative study of factors resulting in care delays for adults with meningitis in Zambia

BACKGROUND

Meningitis causes significant mortality in regions with high comorbid HIV and TB. Improved outcomes are hindered by limited understanding of factors that delay adequate care.

METHODS

In-depth interviews of patients admitted to the University Teaching Hospital with suspected meningitis, their caregivers, doctors and nurses were conducted. Patient/caregiver interviews explored meningitis understanding, treatment prior to admission and experiences since admission. Provider interviews addressed current and prior experiences with meningitis patients and hospital barriers to care. A conceptual framework based on the Three Delays Model identified factors that delayed care.

RESULTS

Twenty-six patient/caregiver, eight doctor and eight nurse interviews occurred. Four delays were identified: in-home care; transportation to a health facility; clinic/first-level hospital care; and third-level hospital. Overcrowding and costly diagnostic testing delayed outpatient care; 23% of patients began with treatment inside the home due to prior negative experiences with biomedical care. Admission occurred after multiple clinic visits, where subsequent delays occurred during testing and treatment.

CONCLUSIONS

Delays in care from home to hospital impair quality meningitis care in Zambia. Interventions to improve outcomes must address patient, community and health systems factors. Patient/caregiver education regarding signs of meningitis and indications for care-seeking are warranted to reduce treatment delays.

Large vessel occlusion prediction scales provide high negative but low positive predictive values in prehospital suspected stroke patients

Introduction

We studied a registry of Emergency Medical Systems (EMS) identified prehospital suspected stroke patients brought to an academic endovascular capable hospital over 1 year to assess the prevalence of disease and externally validate large vessel occlusion (LVO) stroke prediction scales with a focus on predictive values.

Methods

All patients had last known well times within 6 hours and a positive prehospital Cincinnati Prehospital Stroke Scale. LVO prediction scale scores were retrospectively calculated from emergency department arrival National Institutes of Health Stroke Scale scores. Final diagnoses were determined by chart review. Prevalence and diagnostic performance statistics were calculated. We prespecified analyses to identify scale thresholds with positive predictive values (PPVs) ≥80% and negative predictive values (NPVs) ≥95%. A secondary analysis identified thresholds with PPVs ≥50%.

Results

Of 220 EMS transported patients, 13.6% had LVO stroke, 15.9% had intracranial haemorrhage, 20.5% had non-LVO stroke and 50% had stroke mimic diagnoses. LVO stroke prevalence was 15.8% among the 184 diagnostic performance study eligible patients. Only Field Assessment Stroke Triage for Emergency Destination (FAST-ED) ≥7 had a PPV ≥80%, but this threshold missed 83% of LVO strokes. FAST-ED ≥6, Prehospital Acute Severity Scale =3 and Rapid Arterial oCclusion Evaluation ≥7 had PPVs ≥50% but sensitivities were <50%. Several standard and lower alternative scale thresholds achieved NPVs ≥95%, but false positives were common.

Conclusions

Diagnostic performance tradeoffs of LVO prediction scales limited their ability to achieve high PPVs without missing most LVO strokes. Multiple scales provided high NPV thresholds, but these were associated with many false positives.

Axonal Charcot-Marie-Tooth Disease: from Common Pathogenic Mechanisms to Emerging Treatment Opportunities

Inherited peripheral neuropathies are a genetically and phenotypically diverse group of disorders that lead to degeneration of peripheral neurons with resulting sensory and motor dysfunction. Genetic neuropathies that primarily cause axonal degeneration, as opposed to demyelination, are most often classified as Charcot-Marie-Tooth disease type 2 (CMT2) and are the focus of this review. Gene identification efforts over the past three decades have dramatically expanded the genetic landscape of CMT and revealed several common pathological mechanisms among various forms of the disease. In some cases, identification of the precise genetic defect and/or the downstream pathological consequences of disease mutations have yielded promising therapeutic opportunities. In this review, we discuss evidence for pathogenic overlap among multiple forms of inherited neuropathy, highlighting genetic defects in axonal transport, mitochondrial dynamics, organelle-organelle contacts, and local axonal protein translation as recurrent pathological processes in inherited axonal neuropathies. We also discuss how these insights have informed emerging treatment strategies, including specific approaches for single forms of neuropathy, as well as more general approaches that have the potential to treat multiple types of neuropathy. Such therapeutic opportunities, made possible by improved understanding of molecular and cellular pathogenesis and advances in gene therapy technologies, herald a new and exciting phase in inherited peripheral neuropathy.

Deep clinicopathological phenotyping identifies a previously unrecognized pathogenic EMD splice variant

Exome sequencing (ES) has revolutionized rare disease management, yet only ~25%-30% of patients receive a molecular diagnosis. A limiting factor is the quality of available phenotypic data. Here, we describe how deep clinicopathological phenotyping yielded a molecular diagnosis for a 19-year-old proband with muscular dystrophy and negative clinical ES. Deep phenotypic analysis identified two critical data points: (1) the absence of emerin protein in muscle biopsy and (2) clinical features consistent with Emery-Dreifuss muscular dystrophy. Sequencing data analysis uncovered an ultra-rare, intronic variant in EMD, the gene encoding emerin. The variant, NM_000117.3: c.188-6A > G, is predicted to impact splicing by in silico tools. This case thus illustrates how better integration of clinicopathologic data into ES analysis can enhance diagnostic yield with implications for clinical practice.

Loss of Tsc1 in cerebellar Purkinje cells induces transcriptional and translation changes in FMRP target transcripts

Tuberous sclerosis complex (TSC) is a genetic disorder that is associated with multiple neurological manifestations. Previously, we demonstrated that Tsc1 loss in cerebellar Purkinje cells (PCs) can cause altered social behavior in mice. Here, we performed detailed transcriptional and translational analyses of Tsc1-deficient PCs to understand the molecular alterations in these cells. We found that target transcripts of the Fragile X Mental Retardation Protein (FMRP) are reduced in mutant PCs with evidence of increased degradation. Surprisingly, we observed unchanged ribosomal binding for many of these genes using translating ribosome affinity purification. Finally, we found that multiple FMRP targets, including SHANK2, were reduced, suggesting that compensatory increases in ribosomal binding efficiency may be unable to overcome reduced transcript levels. These data further implicate dysfunction of FMRP and its targets in TSC and suggest that treatments aimed at restoring the function of these pathways may be beneficial.

Machine Learning-Driven Metabolomic Evaluation of Cerebrospinal Fluid: Insights Into Poor Outcomes After Aneurysmal Subarachnoid Hemorrhage

BACKGROUND

Aneurysmal subarachnoid hemorrhage (aSAH) is associated with a high mortality and poor neurologic outcomes. The biologic underpinnings of the morbidity and mortality associated with aSAH remain poorly understood.

OBJECTIVE

To ascertain potential insights into pathological mechanisms of injury after aSAH using an approach of metabolomics coupled with machine learning methods.

METHODS

Using cerebrospinal fluid (CSF) samples from 81 aSAH enrolled in a retrospective cohort biorepository, samples collected during the peak of delayed cerebral ischemia were analyzed using liquid chromatography-tandem mass spectrometry. A total of 138 metabolites were measured and quantified in each sample. Data were analyzed using elastic net (EN) machine learning and orthogonal partial least squares-discriminant analysis (OPLS-DA) to identify the leading CSF metabolites associated with poor outcome, as determined by the modified Rankin Scale (mRS) at discharge and at 90 d. Repeated measures analysis determined the effect size for each metabolite on poor outcome.

RESULTS

EN machine learning and OPLS-DA analysis identified 8 and 10 metabolites, respectively, that predicted poor mRS (mRS 3-6) at discharge and at 90 d. Of these candidates, symmetric dimethylarginine (SDMA), dimethylguanidine valeric acid (DMGV), and ornithine were consistent markers, with an association with poor mRS at discharge (P = .0005, .002, and .0001, respectively) and at 90 d (P = .0036, .0001, and .004, respectively). SDMA also demonstrated a significantly elevated CSF concentration compared with nonaneurysmal subarachnoid hemorrhage controls (P = .0087).

CONCLUSION

SDMA, DMGV, and ornithine are vasoactive molecules linked to the nitric oxide pathway that predicts poor outcome after severe aSAH. Further study of dimethylarginine metabolites in brain injury after aSAH is warranted.

Uric Acid and Gluconic Acid as Predictors of Hyperglycemia and Cytotoxic Injury after Stroke

Hyperglycemia is a feature of worse brain injury after acute ischemic stroke, but the underlying metabolic changes and the link to cytotoxic brain injury are not fully understood. In this observational study, we applied regression and machine learning classification analyses to identify metabolites associated with hyperglycemia and a neuroimaging proxy for cytotoxic brain injury. Metabolomics and lipidomics were carried out using liquid chromatography-tandem mass spectrometry in admission plasma samples from 381 patients presenting with an acute stroke. Glucose was measured by a central clinical laboratory, and a subgroup of patients (n = 201) had apparent diffusion coefficient (ADC) imaging quantified on magnetic resonance imaging (MRI) to estimate cytotoxic injury. Uric acid was the leading metabolite in univariate analysis of both hyperglycemia (OR 19.6, 95% CI 8.6-44.7, P = 1.44 × 10-12) and ADC (OR 5.3, 95% CI 2.2-13.0, P = 2.42 × 10-4). To further prioritize model features and account for non-linear correlation structure, a random forest machine learning algorithm was applied to separately model hyperglycemia and ADC. The statistical techniques used have identified uric acid and gluconic acids as leading candidate markers common to all models (R2 = 68%, P = 2.2 × 10-10 for uric acid; R2 = 15%, P = 8.09 × 10-10 for gluconic acid). Both uric acid and gluconic acid were associated with hyperglycemia and cytotoxic brain injury. Both metabolites are linked to oxidative stress, which highlights two candidate targets for limiting brain injury after stroke.

Home-cage monitoring ascertains signatures of ictal and interictal behavior in mouse models of generalized seizures

Epilepsy is a significant contributor to worldwide disability. In epilepsy, disability can be broadly divided into two components: ictal (pertaining to the burden of unpredictable seizures and associated medical complications including death) and interictal (pertaining to more pervasive debilitating changes in cognitive and emotional behavior). In this study, we objectively and noninvasively appraise aspects of ictal and interictal behavior in mice using instrumented home-cage chambers designed to assay kinematic and appetitive behavioral measures. Through daily intraperitoneal injections of the chemoconvulsant pentylenetetrazole (PTZ) applied to C57BL/6J mice, we coordinately measure how “behavioral severity” (complex dynamic changes in movement and sheltering behavior) and convulsive severity (latency and occurrence of convulsive seizures) evolve or kindle with repeated injections. By closely studying long epochs between PTZ injections, we identify an interictal syndrome of nocturnal hypoactivity and increased sheltering behavior which remits with the cessation of seizure induction. We observe elements of this interictal behavioral syndrome in seizure-prone DBA/2J mice and in mice with a pathogenic Scn1a mutation (modeling Dravet syndrome). Through analyzing their responses to PTZ, we illustrate how convulsive severity and “behavioral” severity are distinct and independent aspects of the overall severity of a PTZ-induced seizure. Our results illustrate the utility of an ethologically centered automated approach to quantitatively appraise murine expressions of disability in mouse models of seizures and epilepsy. In doing so, this study highlights the very unique psychopharmacological profile of PTZ.

Past and Present of Eye Movement Abnormalities in Ataxia-Telangiectasia

Ataxia-telangiectasia is the second most common autosomal recessive hereditary ataxia, with an estimated incidence of 1 in 100,000 births. Besides ataxia and ocular telangiectasias, eye movement abnormalities have long been associated with this disorder and is frequently present in almost all patients. A handful of studies have described the phenomenology of ocular motor deficits in ataxia-telangiectasia. Contemporary literature linked their physiology to cerebellar dysfunction and secondary abnormalities at the level of brainstem. These studies, while providing a proof of concept of ocular motor physiology in disease, i.e., ataxia-telangiectasia, also advanced our understanding of how the cerebellum works. Here, we will summarize the clinical abnormalities seen with ataxia-telangiectasia in each subtype of eye movements and subsequently describe the underlying pathophysiology. Finally, we will review how these deficits are linked to abnormal cerebellar function and how it allows better understanding of the cerebellar physiology.

The neutrophil-to-lymphocyte and monocyte-to-lymphocyte ratios are independently associated with neurological disability and brain atrophy in multiple sclerosis

BACKGROUND

Serum hematological indices such as the neutrophil-lymphocyte ratio (NLR) or monocyte-lymphocyte ratio (MLR) have been used as biomarkers of pathogenic inflammation and prognostication in multiple areas of medicine; recent evidence shows correlation with psychological parameters as well.

OBJECTIVES/AIMS

To characterize clinical, neuroimaging, and psycho-neuro-immunological associations with NLR and MLR in persons with multiple sclerosis (MS).

METHODS

We identified a large cohort of clinically well-defined patients from our longitudinal database that included MS-related outcomes, disease-modifying therapy, patient-reported outcome (PRO) measures, and quantified cerebral MRI at 1.5 T. We queried hospital records for complete blood counts within 2 months of each clinic visit and excluded those obtained during clinical relapses. Four hundred eighty-three patients, with a mean of 3 longitudinal observations each, were identified who met these criteria. Initial analyses assessed the association between NLR and MLR as the outcomes, and psychological and demographic predictors in univariable and multivariable models controlling for age, gender and treatment. The second set of analyses assessed the association between clinical and MRI outcomes including whole brain atrophy and T2-hyperintense lesion volume, with NLR and MLR as predictors in univariable and multivariable models. All analyses used a mixed effects linear or logistic regression model with repeated measures.

RESULTS

Unadjusted analyses demonstrated significant associations between higher (log-transformed) NLR (but not MLR) and PRO measures including increasing depression (p = 0.01), fatigue (p < 0.01), and decreased physical quality of life (p < 0.01). Higher NLR and MLR strongly predicted increased MS-related disability as assessed by the Expanded Disability Status Scale, independent of all demographic, clinical, treatment-related, and psychosocial variables (p < 0.001). Lastly, higher NLR and MLR significantly discriminated progressive from relapsing status (p ≤ 0.01 for both), and higher MLR correlated with increased whole-brain atrophy (p < 0.05) but not T2 hyperintense lesion volume (p > 0.05) even after controlling for all clinical and demographic covariates. Sensitivity analyses using a subset of untreated patients (N = 146) corroborated these results.

CONCLUSIONS

Elevated NLR and MLR may represent hematopoetic bias toward increased production and pro-inflammatory priming of the myeloid innate immune system (numerator) in conjunction with dysregulated adaptive immune processes (denominator), and consequently reflect a complementary and independent marker for severity of MS-related neurological disability and MRI outcomes.

Measurement of spinal cord atrophy using phase sensitive inversion recovery (PSIR) imaging in motor neuron disease

BACKGROUND

The spectrum of motor neuron disease (MND) includes numerous phenotypes with various life expectancies. The degree of upper and lower motor neuron involvement can impact prognosis. Phase sensitive inversion recovery (PSIR) imaging has been shown to detect in vivo gray matter (GM) and white matter (WM) atrophy in the spinal cord of other patient populations but has not been explored in MND.

METHODS

In this study, total cord, WM and GM areas of ten patients with a diagnosis within the MND spectrum were compared to those of ten healthy controls (HC). Patients' diagnosis included amyotrophic lateral sclerosis (ALS), primary lateral sclerosis, primary muscular atrophy, facial onset sensory and motor neuronopathy and ALS-Frontotemporal dementia. Axial 2D PSIR images were acquired at four cervical disc levels (C2-C3, C3-C4, C5-C6 and C7-T1) with a short acquisition time (2 minutes) protocol. Total cross-sectional areas (TCA), GM and WM areas were measured using a combination of highly reliable manual and semi-automated methods. Cord areas in MND patients were compared with HC using linear regression analyses adjusted for age and sex. Correlation of WM and GM areas in MND patients was explored to gain insights into underlying atrophy patterns.

RESULTS

MND patients as a group had significantly smaller cervical cord GM area compared to HC at all four levels (C2-C3: p = .009; C3-C4: p = .001; C5-C6: p = .006; C7-T1: p = .002). WM area at C5-C6 level was significantly smaller (p = .001). TCA was significantly smaller at C3-C4 (p = .018) and C5-C6 (p = .002). No significant GM and WM atrophy was detected in the two patients with predominantly bulbar phenotype. Concomitant GM and WM atrophy was detected in solely upper or lower motor neuron level phenotypes. There was a significant correlation between GM and WM areas at all four levels in this diverse population of MND.

CONCLUSION

Spinal cord GM and WM atrophy can be detected in vivo in patients within the MND spectrum using a short acquisition time 2D PSIR imaging protocol. PSIR imaging shows promise as a method for quantifying spinal cord involvement and thus may be useful for diagnosis, prognosis and for monitoring disease progression.

Mapping movement, mood, motivation and mentation in the subthalamic nucleus

The anatomical connections of the subthalamic nucleus (STN) have driven hypotheses about its functional anatomy, including the hypothesis that the precise anatomical location of STN deep brain stimulation (DBS) contributes to the variability of motor and non-motor responses across patients with Parkinson's disease (PD). We previously tested the hypothesis using a three-dimensional (3D) statistical method to interpret the acute effects of unilateral DBS at each patient's clinically optimized DBS settings and active contact. Here, we report a similar analysis from a new study in which DBS parameters were standardized and DBS locations were chosen blind to clinical response. In 74 individuals with PD and STN DBS, STN contacts were selected near the dorsal and ventral borders of the STN contralateral to the more affected side of the body. Participants were tested off PD medications in each of three unilateral DBS conditions (ventral STN DBS, dorsal STN DBS and DBS off) for acute effects on mood, apathy, working memory, response inhibition and motor function. Voltage, frequency and pulse width were standardized, and participants and raters were blind to condition. In a categorical analysis, both dorsal and ventral STN DBS improved mean motor function without affecting cognitive measures. Ventral STN DBS induced greater improvement in rigidity and anxiety than dorsal STN DBS. In the 3D analysis, contact location was significant for body hypokinesia, rigidity and resting tremor, with the greatest improvement occurring with DBS in dorsal STN and zona incerta. The 3D results provide new, direct functional evidence for the anatomically derived model of STN, in which motor function is best represented in dorsal STN. However, our data suggest that functional segregation between motor and non-motor areas of the STN is limited, because locations that induced improvements in motor function and mood overlapped substantially.

Thalamic Volume Is Reduced in Cervical and Laryngeal Dystonias

BACKGROUND

Dystonia, a debilitating movement disorder characterized by abnormal fixed positions and/or twisting postures, is associated with dysfunction of motor control networks. While gross brain lesions can produce secondary dystonias, advanced neuroimaging techniques have been required to identify network abnormalities in primary dystonias. Prior neuroimaging studies have provided valuable insights into the pathophysiology of dystonia, but few directly assessed the gross volume of motor control regions, and to our knowledge, none identified abnormalities common to multiple types of idiopathic focal dystonia.

METHODS

We used two gross volumetric segmentation techniques and one voxelwise volumetric technique (voxel based morphometry, VBM) to compare regional volume between matched healthy controls and patients with idiopathic primary focal dystonia (cervical, n = 17, laryngeal, n = 7). We used (1) automated gross volume measures of eight motor control regions using the FreeSurfer analysis package; (2) blinded, anatomist-supervised manual segmentation of the whole thalamus (also gross volume); and (3) voxel based morphometry, which measures local T1-weighted signal intensity and estimates gray matter density or volume at the level of single voxels, for both whole-brain and thalamus.

RESULTS

Using both automated and manual gross volumetry, we found a significant volume decrease only in the thalamus in two focal dystonias. Decreases in whole-thalamic volume were independent of head and brain size, laterality of symptoms, and duration. VBM measures did not differ between dystonia and control groups in any motor control region.

CONCLUSIONS

Reduced thalamic gross volume, detected in two independent analyses, suggests a common anatomical abnormality in cervical dystonia and spasmodic dysphonia. Defining the structural underpinnings of dystonia may require such complementary approaches.