Faculty Bibliography

OBJECTIVE:To estimate the prevalence of having at least one or two or more chronic health conditions among US adults with self-reported migraine or severe headaches. DESIGN/METHODS:Cross-sectional study. METHODS:Using data collected from the 2013-2015 National Health Interview Survey, we examined adults with and without migraine or severe headache and associations with chronic obstructive pulmonary disease, cancer, heart disease, stroke, diabetes, and hypertension. We calculated point estimates, variances, and 95% confidence intervals and conducted bivariate and multivariable logistic regression modeling to examine the relationships between migraine or severe headache and each of the chronic health conditions, as well as multinomial modeling, to examine the relationship between migraine or severe headache and having one or more chronic health conditions. RESULTS:A total of 104,926 people were in the study. Adults aged 18 to 44 years (18.2%), women (20.1%), and those with some college education (17.6%) had the greatest proportion with migraine or severe headache (P < 0.0001). Using multinomial modeling with the number of chronic health conditions as the dependent variable, adults reporting migraine had an increased odds of reporting a single chronic health condition (adjusted odds ratio [aOR] = 1.7, 95% confidence interval [CI] = 1.6-1.8) and more than double the odds of reporting two or more chronic health conditions (aOR = 2.5, 95% CI = 2.3-2.8) compared with adults who did not have migraine or severe headache. CONCLUSIONS:Our study confirms observed relationships between migraine or severe headache and chronic health conditions and supports the need for further research to uncover the shared biological pathways.

We analyze the role of inhibition in sustaining focal epileptic seizure activity. We review ongoing seizure activity at the mesoscopic scale that can be observed with microelectrode arrays as well as at the macroscale of standard clinical EEG. We provide clinical, experimental, and modeling data to support the hypothesis that paroxysmal depolarization (PD) is a critical component of the ictal machinery. We present dual-patch recordings in cortical cultures showing reduced synaptic transmission associated with presynaptic occurrence of PD, and we find that the PD threshold is cell size related. We further find evidence that optically evoked PD activity in parvalbumin neurons can promote propagation of neuronal excitation in neocortical networks in vitro. Spike sorting results from microelectrode array measurements around ictal wave propagation in human focal seizures demonstrate a strong increase in putative inhibitory firing with an approaching excitatory wave, followed by a sudden reduction of firing at passage. At the macroscopic level, we summarize evidence that this excitatory ictal wave activity is strongly correlated with oscillatory activity across a centimeter-sized cortical network. We summarize Wilson-Cowan-type modeling showing how inhibitory function is crucial for this behavior. Our findings motivated us to develop a network motif of neurons in silico, governed by a reduced version of the Hodgkin-Huxley formalism, to show how feedforward, feedback, PD, and local failure of inhibition contribute to observed dynamics across network scales. The presented multidisciplinary evidence suggests that the PD not only is a cellular marker or epiphenomenon but actively contributes to seizure activity.NEW & NOTEWORTHY We present mechanisms of ongoing focal seizures across meso- and macroscales of microelectrode array and standard clinical recordings, respectively. We find modeling, experimental, and clinical evidence for a dual role of inhibition across these scales: local failure of inhibition allows propagation of a mesoscopic ictal wave, whereas inhibition elsewhere remains intact and sustains macroscopic oscillatory activity. We present evidence for paroxysmal depolarization as a mechanism behind this dual role of inhibition in shaping ictal activity.

Cognitive impairment is frequent in progressive supranuclear palsy (PSP) and less common in multiple system atrophy (MSA), but characteristics and progression compared with Parkinson's disease (PD) need to be properly defined. We evaluated 35 PSP with Richardson's syndrome (PSP-RS), 30 MSA as well as 65 age-, sex-, and education-matched PD with an extensive clinical and neuropsychological assessment, allowing Level II cognitive diagnosis. Eighteen PSP, 12 MSA and 30 PD had a second evaluation between 12 and 18 months (mean 15 months) after the first assessment. PSP performance at Montreal Cognitive Assessment (MoCA), verbal fluencies (phonemic and semantic tasks), Stroop test (Error and Time), Digit Span Sequencing (DSS), incomplete letters of Visual Object and Space Perception (VOSP) and Benton's Judgment of Line Orientation (JLO) performance were significantly poorer at baseline compared to PD and MSA. Executive, language and visuospatial abilities declined longitudinally in PSP, but not in PD and MSA. After 1.5 year, 16% of PSP converted to dementia. Our study provides evidence that cognitive progression is more severe and rapid in PSP-RS than PD and MSA. Further, we observed that MoCA, verbal fluency (particularly semantic), DSS and Benton's JLO are valuable tests to detect cognitive progression in PSP-RS and may be proposed as possible biomarker to assess efficacy of disease modification strategies.

The glossopharyngeal and vagus cranial nerves provide the brainstem with sensory inputs from different receptors in the heart, lung, and vasculature. This afferent information is critical for the short-term regulation of arterial blood pressure and the buffering of emotional and physical stressors. Glossopharyngeal afferents supply the medulla with continuous mechanoreceptive signals from baroreceptors at the carotid sinus. Vagal afferents ascending from the heart supply mechanoreceptive signals from baroreceptors in different reflexogenic areas including the aortic arch, atria, ventricles, and pulmonary arteries. Ultimately, afferent information from each of these distinct pressure/volume baroreceptors is all relayed to the nucleus tractus solitarius, integrated within the medulla, and used to rapidly adjust sympathetic and parasympathetic activity back to the periphery. Lesions that selectively destroy the afferent fibers of the vagus and/or glossopharyngeal nerves can interrupt the transmission of baroreceptor signaling, leading to extreme blood pressure fluctuations. Vagal efferent neurons project back to the heart to provide parasympathetic cholinergic inputs. When activated, they trigger profound bradycardia, reduce myocardial oxygen demands, and inhibit acute inflammation. Impairment of the efferent vagal fibers seems to play a role in stress-induced neurogenic heart disease (i.e., takotsubo cardiomyopathy). This focused review describes: (1) the importance of the vagus and glossopharyngeal afferent neurons in regulating arterial blood pressure and heart rate, (2) how best to assess afferent and efferent cardiac vagal function in the laboratory, and (3) two clinical phenotypes that arise when the vagal and/or glossopharyngeal nerves do not survive development or are functionally impaired.

BACKGROUND:Recent studies estimate nearly half of the US population can access mobile medical applications (apps) on their smartphones. The are no systematic data available on apps focused on stroke survivors/caregivers. OBJECTIVE:To identify apps (a) designed for stroke survivors/caregivers, (b) dealing with a modifiable stroke risk factor (SRF), or (c) were developed for other purposes but could potentially be used by stroke survivors/caregivers. METHODS:A systematic review of the medical apps in the US Apple iTunes store was conducted between August 2013 and January 2016 using 18 predefined inclusion/exclusion criteria. SRFs considered were: diabetes, hypertension, smoking, obesity, atrial fibrillation, and dyslipidemia. RESULTS:Out of 30,132 medical apps available, 843 (2.7%) eligible apps were identified. Of these apps, (n = 74, 8.7%) apps were specifically designed for stroke survivors/caregivers use and provided the following services: language/speech therapy (n = 28, 37%), communication with aphasic patients (n = 19, 25%), stroke risk calculation (n = 11, 14%), assistance in spotting an acute stroke (n = 8, 10%), detection of atrial fibrillation (n = 3, 4%), direction to nearby emergency room (n = 3, 4%), physical rehabilitation (n = 3, 4%), direction to the nearest certified stroke center (n = 1, < 2%), and visual attention therapy (n = 1, <2%). 769 apps identified that were developed for purposes other than stroke. Of these, the majority (n = 526, 68%) addressed SRFs. CONCLUSIONS:Over 70 medical apps exist to specifically support stroke survivors/caregivers and primarily targeted language and communication difficulties. Apps encompassing most stroke survivor/caregiver needs could be developed and tested to ensure the issues faced by these populations are being adequately addressed.

OBJECTIVE:To determine the underlying etiology in a patient with progressive dementia with extrapyramidal signs and chronic inflammation referred to the National Institutes of Health Undiagnosed Diseases Program. METHODS:Extensive investigations included metabolic profile, autoantibody panel, infectious etiologies, genetic screening, whole exome sequencing and the phage-display assay, VirScan, for viral immune responses. An etiological diagnosis was established post-mortem. RESULTS:Using VirScan, enrichment of dengue viral antibodies were detected in cerebrospinal fluid as compared to serum. No virus was detected in serum or cerebrospinal fluid, but post-mortem analysis confirmed dengue virus in the brain by immunohistochemistry, in situ hybridization, quantitative polymerase chain reaction and sequencing. Dengue virus was also detectable by polymerase chain reaction and sequencing from brain biopsy tissue collected 33 months ante-mortem, confirming a chronic infection despite a robust immune response directed against the virus. Immunoprofiling and whole exome sequencing of the patient did not reveal any immunodeficiency and sequencing of the virus demonstrated wild-type dengue virus in the central nervous system. INTERPRETATION/CONCLUSIONS:Dengue virus is the most common arbovirus worldwide and represents a significant public health concern. Infections with dengue virus are usually self-limiting and chronic dengue infections have not been previously reported. Our findings suggest that dengue virus infections may persist in the central nervous system and should be considered in patients with progressive dementia with extrapyramidal features in endemic regions or with relevant travel history. Further, this work highlights the utility of comprehensive antibody profiling assays to aid in the diagnosis of encephalitis of unknown etiologies. This article is protected by copyright. All rights reserved.

Myelin has traditionally been considered a static structure that is produced and assembled during early developmental stages. While this characterization is accurate in some contexts, recent studies have revealed that oligodendrocyte generation and patterns of myelination are dynamic and potentially modifiable throughout life. Unique structural and biochemical properties of the myelin sheath provide opportunities for the development and implementation of multimodal label-free and fluorescence optical imaging approaches. When combined with genetically encoded fluorescent tags targeted to distinct cells and subcellular structures, these techniques offer a powerful methodological toolbox for uncovering mechanisms of myelin generation and plasticity in the live brain. Here, we discuss recent advances in these approaches that have allowed the discovery of several forms of myelin plasticity in developing and adult nervous systems. Using these techniques, long-standing questions related to myelin generation, remodeling, and degeneration can now be addressed.