Axons are a unique cellular structure that allows for the communication between neurons. Axon damage compromises neuronal communications and often leads to functional deficits. Thus, developing strategies that promote effective axon regeneration for functional restoration is highly desirable. One fruitful approach is to dissect the regenerative mechanisms used by some types of neurons in both mammalian and nonmammalian systems that exhibit spontaneous regenerative capacity. Additionally, numerous efforts have been devoted to deciphering the barriers that prevent successful axon regeneration in the most regeneration-refractory system-the adult mammalian central nervous system. As a result, several regeneration-promoting strategies have been developed, but significant limitations remain. This review is aimed to summarize historic progression and current understanding of this exciting yet incomplete endeavor.
The analysis of nuclear morphology plays an important role in glioma diagnosis and grading. We previously described intranuclear rods (rods) labeled with the SDL.3D10 monoclonal antibody against class III beta-tubulin (TUBB3) in human ependymomas. In a cohort of adult diffuse gliomas, we identified nuclear rods in 71.1% of IDH mutant lower-grade gliomas and 13.7% of IDH wild-type glioblastomas (GBMs). The presence of nuclear rods was associated with significantly longer postoperative survival in younger (≤65) GBM patients. Consistent with this, nuclear rods were mutually exclusive with Ki67 staining and their prevalence in cell nuclei inversely correlated with the Ki67 proliferation index. In addition, rod-containing nuclei showed a relative depletion of lamin B1, suggesting a possible association with senescence. To gain insight into their functional significance, we addressed their antigenic properties. Using a TUBB3-null mouse model, we demonstrate that the SDL.3D10 antibody does not bind TUBB3 in rods but recognizes an unknown antigen. In the present study, we show that rods show immunoreactivity for the nucleotide synthesizing enzymes inosine monophosphate dehydrogenase (IMPDH) and cytidine triphosphate synthetase. By analogy with the IMPDH filaments that have been described previously, we postulate that rods regulate the activity of nucleotide-synthesizing enzymes in the nucleus by sequestration, with important implications for glioma behavior.
PURPOSE OF REVIEW: Dementia is a term for loss of memory, language, problem-solving, and other thinking abilities, which significantly interferes with daily life. Certain dementing conditions may also affect visual function. The eye is an accessible window to the brain that can provide valuable information for the early diagnosis of people who suffer from Alzheimer's disease, Parkinson's disease, dementia with Lewy bodies as well as from more rare causes of dementias, such as Creutzfeldt-Jacob and Huntington's diseases. Herein, we present the ocular manifestations of neurocognitive disorders focusing on the neuro-ophthalmic ones and further discuss potential ocular biomarkers that could help in early detection of these disorders. RECENT FINDINGS: Ophthalmic examination along with the recent developments in in-vivo testing have provided a strong foundation of useful knowledge about brain disorder in neurodegenerative diseases without the need for invasive studies. Currently, a number of visual measures, such as visual acuity, contrast sensitivity, pupil response, and saccades in addition to various ophthalmic tests, such as electroretinogram, visual evoked potential, optical coherence tomography (OCT), and OCT-angiography have been widely used and evaluated as potential biomarkers for different stages of dementia. SUMMARY: Ophthalmologic and neuro-ophthalmic evaluation is evolving as an important part of the early diagnosis and management of people with dementia. A particular focus on ocular biomarkers in dementing illnesses has arisen over the past few years and there are several promising measures and imaging tools that have been proposed as potential biomarkers for these diseases.
BACKGROUND: Optic nerve astrocytomas (ONAs) are neurological neoplasms in the central nervous system (CNS), and they have the highest incidence rate among all the tumor types in the visual pathway. In this study, we conducted a Surveillance, Epidemiology, and End Results (SEER) -based research to explore the demographic, survival, and prognostic factors of patients diagnosed with ONAs. METHODS: Utilizing the SEER database, we retrospectively evaluated data of patients diagnosed with ONAs of all ages from 1984 to 2016. We used the Student's t distribution to test variables of patients and various characteristics, and Kaplan-Meier curve to illustrate overall survival (OS) with 95.0% confidence intervals (CIs). We also performed univariate and multivariate analyses to evaluate various variables' validity on overall survival. RESULTS: A total of 1004 cases were analyzed, and revealed that age (P<0.001, hazard ratio (HR) = 8.830, 95% CI: 4.088-19.073), tumor grade (P<0.001, HR = 1.927, 95% CI: 1.516-2.450), diagnostic confirmation (P<0.001, HR = 2.444, 95% CI: 1.632-3.660), and histology type (P = 0.046, HR = 1.563, 95% CI: 1.008-2.424) of the tumor were associated with decreased survival. CONCLUSIONS: From this large, comparative study of ONAs, we found that younger age may be considered as a protective indicator, while high-grade astrocytic tumors have a worse prognosis. We also found that diagnostic confirmation and tumor grade were independent prognostic factors in this patient population.
PURPOSE: To examine the association between Post-Concussion Symptom Scale (PCSS) scores, Convergence Insufficiency Symptom Survey (CISS) scores, and oculomotor deficits post-concussion. METHODS: Records of adolescent patients examined in a multidisciplinary concussion clinic between July 2014 and May 2019 were reviewed. PCSS and CISS scores, results of eye examination and oculomotor assessment, concussion history, and demographics were abstracted. RESULTS: One hundred and forty patient records (median age, 15.3 years; 52 males, presented 109 days (median) from their most recent concussion) met inclusion criteria. Mean total scores on PCSS and CISS were 46.67 ± 25.89 and 27.13 ± 13.22, respectively, and were moderately correlated with each other (r = 0.53, p < .001). Oculomotor deficits were observed in 123 (88%) patients. Step-wise linear regression identified increased PCSS total score to be significantly associated with decreased amplitude of accommodation (p < .001). Increased CISS total score was significantly associated with receded near point of convergence, developmental eye movement test error scores, and cause of concussion. CONCLUSION: High PCSS scores may indicate an accommodation deficit and thus prompt an oculomotor assessment in patients following a concussion. Using the CISS and a detailed oculomotor assessment may reveal underlying oculomotor deficits, which may benefit from treatment.
Cerebral visual impairment (CVI) often presents with deficits associated with higher order visual processing. We report a case of an individual with CVI who uses a verbal mediation strategy to perceive and interact with his visual surroundings. Visual perceptual performance was assessed using a virtual reality based visual search task combined with eye tracking. Functional magnetic resonance imaging (fMRI) was employed to identify the neural correlates associated with this strategy. We found that when using verbal mediation, the individual could readily detect and track the target within the visual scene which was associated with robust activation within a network of occipito-parieto-temporal visual cortical areas. In contrast, when not using verbal mediation, the individual was completely unable to perform the task, and this was associated with dramatically reduced visual cortical activation. This unique compensatory strategy may be related to the individual's use of verbal working memory for the purposes of understanding complex visual information.
History A 24-year-old right-handed woman presented to a neuro-ophthalmology clinic in Massachusetts in the summer with acute binocular diplopia when looking down and to the left, which started about 1 month earlier. Her medical history was notable for Raynaud syndrome, recurrent streptococcal pharyngitis, and an allergy to amoxicillin. Three days prior to developing diplopia, she presented to an outside emergency department due to fever, chills, and back pain. She received ciprofloxacin for presumed urinary tract infection based on urinalysis, which demonstrated few bacteria and was negative for leukocyte esterase, nitrites, and white blood cells. She then presented again to an outside emergency department for diplopia evaluation. Initial MRI and MR angiography of the brain at that time did not demonstrate any relevant findings, and the patient was referred to our department for neuro-ophthalmic evaluation, where she was seen 4 weeks later. Neuro-ophthalmic examination revealed 20/20 visual acuity in both eyes, and a right hypertropia in left gaze, downgaze and right head tilt, with right eye excyclotorsion. There were no ocular signs of myasthenia gravis or thyroid eye disease, nor did the patient report ocular or systemic symptoms. She denied recent travel. High-spatial-resolution MRI of the brain and orbit were performed.
BACKGROUND: The typical natural history of optic neuritis is subjected to important exceptions. Recognition of these exceptions has led to valuable insights regarding specific etiologies of optic neuritis. Exceptions to the natural history of recovering optic neuritis are well-defined (e.g., chronic relapsing inflammatory optic neuropathy), but exceptions to the natural history of evolving optic neuritis are less so. METHODS: Medical records of patients illustrating an atypical course of evolving optic neuritis were reviewed in a retrospective manner. Each patient was treated by at least one of the authors. RESULTS: Four patients were identified who illustrated an atypical natural history of incipient optic neuritis. Diagnoses included idiopathic optic neuritis, seropositive neuromyelitis optica spectrum disease, anti-myelin oligodendrocyte glycoprotein antibody disease, and multiple sclerosis in 1 patient each. Features of interest included an atypical temporal relationship between development of pain and onset of clinical optic neuropathy, an unusually protracted duration of pain, and an unusually long duration of worsening optic neuropathy before stabilization. CONCLUSIONS: This case series illustrates the substantial clinical heterogeneity which may be observed in the evolution of optic neuritis. The temporal relationship between development of pain and onset of clinical optic neuropathy, the duration of pain, and duration of worsening optic neuropathy before stabilization are all subjected to significant variability. Although most patients with optic neuritis present with painful vision loss which progresses over 1 week or less, careful attention to the exceptions described herein may facilitate earlier recognition of diagnostically challenging cases.
Background: Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is characterized by leukoencephalopathy leading to cognitive impairment. Subtle cognitive deficits can be observed early in the course of the disease, before the occurrence of the first stroke. Therefore, markers that can predict disease progression at this early stage, when interventions are likely to alter disease course, are needed. We aimed to examine the biological cascade of microstructural and macrostructural white matter (WM) abnormalities underlying cognitive deficits in CADASIL. Methods: We examined 20 nondemented CADASIL mutation carriers and 23 noncarriers who underwent neuropsychological evaluation and magnetic resonance imaging. Using probabilistic tractography of key WM tracts, we examined group differences in diffusivity measures and WM hyperintensity volume. Successive mediation models examined whether tract-specific WM abnormalities mediated subtle cognitive differences between CADASIL mutation carriers and noncarriers. Results: The largest effect size differentiating the two groups was observed for left superior longitudinal fasciculus-temporal (SLFt) diffusivity (Cohen's f = 0.49). No group differences were observed with a global diffusion measure. These specific microstructural differences in the SLFt were associated with higher WM hyperintensities burden, and subtle executive deficits in CADASIL mutation carriers. Discussion: Worse diffusivity in the left SLFt is related to greater severity of small vessel disease and worse executive functioning in the asymptomatic stage of the disease. Worse diffusivity of the left SLFt may potentially hold promise as an indicator of disease progression.
PURPOSE: To provide a summary of the neuro-ophthalmic manifestations of coronavirus disease 19 (COVID-19) documented in the literature thus far. METHODS: The PubMed and Google Scholar databases were searched using the keywords: Neuro-Ophthalmology, COVID-19, SARS-CoV-2, and coronavirus. A manual search through reference lists of relevant articles was also performed. RESULTS/CONCLUSIONS: The literature on COVID-associated neuro-ophthalmic disease continues to grow. Afferent neuro-ophthalmic complications associated with COVID-19 include optic neuritis, papillophlebitis, papilledema, visual disturbance associated with posterior reversible encephalopathy syndrome, and vision loss caused by stroke. Efferent neuro-ophthalmic complications associated with COVID-19 include cranial neuropathies, Miller Fisher syndrome, Adie's pupils, ocular myasthenia gravis, nystagmus and eye movement disorders. Proposed mechanisms of neurologic disease include immunologic upregulation, vasodilation and vascular permeability, endothelial dysfunction, coagulopathy, and direct viral neurotropism. When patients present to medical centers with new onset neuro-ophthalmic conditions during the pandemic, COVID-19 infection should be kept on the differential.
BACKGROUND: Cardiovascular risk factors increase the risk of developing dementia, including Alzheimer's disease and vascular dementia. OBJECTIVE: Studying individuals with autosomal dominant mutations leading to the early onset of dementia, this study examines the effect of the global cardiovascular risk profile on early cognitive and neuroimaging features of Alzheimer's disease and vascular dementia. METHODS: We studied 85 non-demented and stroke-free individuals, including 20 subjects with Presenilin1 (PSEN1) E280A mutation leading to the early onset of autosomal dominant Alzheimer's disease (ADAD), 20 subjects with NOTCH3 mutations leading to cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) and to the early onset of vascular dementia, and 45 non-affected family members (non-carriers). All subjects underwent clinical and neuropsychological evaluations and an MRI. The global cardiovascular risk profile was estimated using the office-based Framingham Cardiovascular Risk Profile (FCRP) score. RESULTS: In individuals with CADASIL, a higher FCRP score was associated with a reduced hippocampal volume (B = -0.06, p < 0.05) and an increased severity of cerebral microbleeds (B = 0.13, p < 0.001), lacunes (B = 0.30, p < 0.001), and perivascular space enlargement in the basal ganglia (B = 0.50, p < 0.05). There was no significant association between the FCRP score and neuroimaging measures in ADAD or non-carrier subjects. While the FCRP score was related to performance in executive function in non-carrier subjects (B = 0.06, p < 0.05), it was not significantly associated with cognitive performance in individuals with CADASIL or ADAD. CONCLUSION: Our results suggest that individuals with CADASIL and other forms of vascular cognitive impairment might particularly benefit from early interventions aimed at controlling cardiovascular risks.
Neuronal ceroid lipofuscinoses (NCLs) are a group of rare neurodegenerative storage disorders associated with devastating visual prognosis, with an incidence of 1/1,000,000 in the United States and comparatively higher incidence in European countries. The pathophysiological mechanisms causing NCLs occur due to enzymatic or transmembrane defects in various sub-cellular organelles including lysosomes, endoplasmic reticulum, and cytoplasmic vesicles. NCLs are categorized into different types depending upon the underlying cause i.e., soluble lysosomal enzyme deficiencies or non-enzymatic deficiencies (functions of identified proteins), which are sub-divided based on an axial classification system. In this review, we have evaluated the current evidence in the literature and reported the incidence rates, underlying mechanisms and currently available management protocols for these rare set of neuroophthalmological disorders. Additionally, we also highlighted the potential therapies under development that can expand the treatment of these rare disorders beyond symptomatic relief.
SARS-CoV-2 was originally identified as an outbreak in Wuhan, China towards the end of 2019 and quickly became a global pandemic, with a large death toll. Originally identified as a respiratory disease, similar to previously discovered SARS and MERS type viruses, concern has since been raised about the effects of SARS-CoV-2 infection on the vasculature. This viral-vascular involvement is of particular concern with regards to the small vessels present in the brain, with mounting evidence demonstrating that SARS-CoV-2 is capable of crossing the blood-brain-barrier. Severe symptoms of infection, termed COVID-19, often result in neurological complications, regardless of patient age. These neurological complications range from mild to severe across all demographics, however, the long-term repercussions of neurological involvement on patient health are still unknown.
BACKGROUND: Addison disease, corticosteroid withdrawal, and taking synthetic growth hormone have been linked with development of intracranial hypertension, but there is still debate on whether administration of other exogenous hormones plays a role in precipitating elevated pressure. The growing use of hormonal therapy for gender affirmation provides an opportunity to explore this possibility. METHODS: All transgender patients taking exogenous hormones for female-to-male (FTM) and male-to-female (MTF) transitions who were diagnosed with intracranial hypertension at Massachusetts Eye and Ear Infirmary, Massachusetts General Hospital and Beth Israel Deaconess Medical Center between August 2014 and November 2018 were included in a retrospective review. Visual acuity, type, and dose of exogenous hormone, visual field testing, clinical exam, results of neuroimaging and lumbar puncture, and treatment modalities were catalogued and analyzed. RESULTS: Six transgender individuals were identified. Five were FTM, with an average hormone treatment time of 18.4 months, and one was MTF who had been treated with hormones for 4 years. The average age of all patients was 23.5 years. The average time between onset of symptoms and presentation was 5 months. Fifty percent of the patients reported pulse-synchronous tinnitus, 83% reported positional headache, 33% reported transient visual obscurations, and 16% reported diplopia. Lumbar punctures performed on 4 of the patients revealed elevated opening pressures and normal cerebrospinal fluid constituents. MRI findings consistent with elevated intracranial pressure (ICP) were present in the other 2 patients in whom lumbar puncture was unsuccessful. Four patients were treated with acetazolamide and one was treated with topiramate, with an average follow-up time of 15.7 months. All patients demonstrated bilateral optic disc swelling, and all maintained normal acuity and color vision. Performance on visual field testing was not significantly affected in any patient. CONCLUSIONS: This is the largest reported series to date of gender-transitioning patients with intracranial hypertension, including one novel MTF conversion. These observations warrant further investigation into the possible link of exogenous hormonal therapy and elevated ICP and any mechanisms or confounders underlying this potential association.