Across neurodegenerative diseases, common mechanisms may reveal novel therapeutic targets based on neuronal protection, repair, or regeneration, independent of etiology or site of disease pathology. To address these mechanisms and discuss emerging treatments, in April, 2021, Glaucoma Research Foundation, BrightFocus Foundation, and the Melza M. and Frank Theodore Barr Foundation collaborated to bring together key opinion leaders and experts in the field of neurodegenerative disease for a virtual meeting titled "Solving Neurodegeneration". This "think-tank" style meeting focused on uncovering common mechanistic roots of neurodegenerative disease and promising targets for new treatments, catalyzed by the goal of finding new treatments for glaucoma, the world's leading cause of irreversible blindness and the common interest of the three hosting foundations. Glaucoma, which causes vision loss through degeneration of the optic nerve, likely shares early cellular and molecular events with other neurodegenerative diseases of the central nervous system. Here we discuss major areas of mechanistic overlap between neurodegenerative diseases of the central nervous system: neuroinflammation, bioenergetics and metabolism, genetic contributions, and neurovascular interactions. We summarize important discussion points with emphasis on the research areas that are most innovative and promising in the treatment of neurodegeneration yet require further development. The research that is highlighted provides unique opportunities for collaboration that will lead to efforts in preventing neurodegeneration and ultimately vision loss.
There is a broad differential for patients presenting with congenital facial weakness, and initial misdiagnosis unfortunately is common for this phenotypic presentation. Here we present a framework to guide evaluation of patients with congenital facial weakness disorders to enable accurate diagnosis. The core categories of causes of congenital facial weakness include: neurogenic, neuromuscular junction, myopathic, and other. This diagnostic algorithm is presented, and physical exam considerations, additional follow-up studies and/or consultations, and appropriate genetic testing are discussed in detail. This framework should enable clinical geneticists, neurologists, and other rare disease specialists to feel prepared when encountering this patient population and guide diagnosis, genetic counseling, and clinical care.
OBJECTIVE: The diagnosis of sarcoid optic neuropathy is time-sensitive, as delayed treatment risks irreversible vision loss. We sought to analyze its characteristics and outcomes. METHODS: We performed a multi-center retrospective study of sarcoid optic neuropathy among 5 USA medical centers. Inclusion criteria were: 1) clinical optic neuropathy; 2) optic nerve/sheath enhancement on neuroimaging; 3) pathological confirmation of systemic or nervous system sarcoidosis. RESULTS: Fifty-one patients were included. The median onset age of sarcoid optic neuropathy was 50 years (range, 17-70 years) and 71% were female. The median visual acuity at nadir in the most affected eye was 20/80 (range, 20/20 to no-light-perception). Thirty-four of 50 (68%) patients had radiologic evidence of other nervous system involvement and 20 (39%) patients had symptoms/signs of other cranial nerve dysfunction. Cerebrospinal fluid analysis revealed an elevated white blood cell count in 22 of 31 (71%) patients (median: 14/μL; range: 1-643/μL). Pathologic confirmation of sarcoidosis was by biopsy of systemic/pulmonary site, 34 (67%); optic nerve/sheath, 9 (18%); or other nervous system region, 8 (16%). Forty patients improved with treatment (78%), 98% receiving corticosteroids and 65% receiving steroid-sparing immunosuppressants, yet 11/46 patients (24%) had a visual acuity of 20/200 or worse at last follow-up. CONCLUSIONS: Sarcoid optic neuropathy frequently occurs with other clinical and radiologic abnormalities caused by neurosarcoidosis and diagnostic confirmation occasionally requires optic nerve/sheath biopsy. Improvement with treatment is common but most patients have some residual visual disability. Improved recognition and a more expeditious diagnosis and treatment may spare patients from permanent vision loss.
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was originally identified as an outbreak in Wuhan, China, toward 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 Middle East respiratory syndrome (MERS), 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, termed coronavirus disease 2019 (COVID-19), often result in neurologic complications, regardless of patient age. These neurologic complications range from mild to severe across all demographics; however, the long-term repercussions of neurologic involvement on patient health are still unknown.
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.
Acute isolated optic neuritis can be the initial presentation of demyelinating inflammatory central nervous system disease related to multiple sclerosis (MS), neuromyelitis optica (NMO) or myelin oligodendrocyte glycoprotein antibody disease (MOG-AD). In addition to the well-characterized brain and spinal cord imaging features, important and characteristic differences in the radiologic appearance of the optic nerves in these disorders are being described, and magnetic resonance imaging (MRI) of the optic nerves is becoming an essential tool in the differential diagnosis of optic neuritis. Whereas typical demyelinating optic neuritis is a relatively mild and self-limited disease, atypical optic neuritis in NMO and MOG-AD is potentially much more vision-threatening and merits a different treatment approach. Thus, differentiation based on MRI features may be particularly important during the first attack of optic neuritis, when antibody status is not yet known. This review discusses the optic nerve imaging in the major demyelinating disorders with an emphasis on clinically relevant differences that can help clinicians assess and manage these important neuro-ophthalmic disorders. It also reviews the utility of optic nerve MRI as a prognostic indicator in acute optic neuritis.
PURPOSE: To review the literature on the efficacy and safety of medical and surgical interventions for indirect traumatic optic neuropathy (TON), defined as injury to the nerve that occurs distal to the optic nerve head. METHODS: A literature search was conducted on October 22, 2019, and updated on April 8, 2020, in the PubMed database for English language original research that assessed the effect of various interventions for indirect TON. One hundred seventy-two articles were identified; 41 met the inclusion criteria outlined for assessment and were selected for full-text review and abstraction. On full-text review, a total of 32 studies met all of the study criteria and were included in the analysis. RESULTS: No study met criteria for level I evidence. Seven studies (1 level II study and 6 level III studies) explored corticosteroid therapy that did not have uniformly better outcomes than observation. Twenty studies (3 level II studies and 17 level III studies) assessed optic canal decompression and the use of corticosteroids. Although visual improvement was noted after decompression, studies that directly compared surgery with medical therapy did not report uniformly improved outcomes after decompression. Four studies (1 level II study and 3 level III studies) evaluated the use of erythropoietin. Although initial studies demonstrated benefit, a direct comparison of its use with observation and corticosteroids failed to confirm the usefulness of this medication. One study (level II) documented visual improvement with levodopa plus carbidopa. Complication rates were variable with all of these interventions. Pharmacologic interventions generally were associated with few complications, whereas optical canal decompression carried risks of serious side effects, including hemorrhages and cerebrospinal fluid leakage. CONCLUSIONS: Despite reports of visual improvement with corticosteroids, optic canal decompression, and medical therapy for indirect TON, the weight of published evidence does not demonstrate a consistent benefit for any of these interventions. In summary, no consensus exists from studies published to date on a preferred treatment for TON. Treatment strategies should be customized for each individual patient. More definitive treatment trials will be needed to identify optimal treatment strategies for indirect TON.
A longstanding question in sensory neuroscience is what types of stimuli drive neurons to fire. The characterization of effective stimuli has traditionally been based on a combination of intuition, insights from previous studies, and luck. A new method termed XDream (EXtending DeepDream with real-time evolution for activation maximization) combined a generative neural network and a genetic algorithm in a closed loop to create strong stimuli for neurons in the macaque visual cortex. Here we extensively and systematically evaluate the performance of XDream. We use ConvNet units as in silico models of neurons, enabling experiments that would be prohibitive with biological neurons. We evaluated how the method compares to brute-force search, and how well the method generalizes to different neurons and processing stages. We also explored design and parameter choices. XDream can efficiently find preferred features for visual units without any prior knowledge about them. XDream extrapolates to different layers, architectures, and developmental regimes, performing better than brute-force search, and often better than exhaustive sampling of >1 million images. Furthermore, XDream is robust to choices of multiple image generators, optimization algorithms, and hyperparameters, suggesting that its performance is locally near-optimal. Lastly, we found no significant advantage to problem-specific parameter tuning. These results establish expectations and provide practical recommendations for using XDream to investigate neural coding in biological preparations. Overall, XDream is an efficient, general, and robust algorithm for uncovering neuronal tuning preferences using a vast and diverse stimulus space. XDream is implemented in Python, released under the MIT License, and works on Linux, Windows, and MacOS.
Given the prevalence of poor adherence to therapy and the biases of self-reporting across healthcare, we hypothesized that an engaging, personalized therapy may improve adherence and treatment outcomes in the home. We tested this hypothesis in the initial indication of amblyopia, a neurodevelopmental disorder for which available treatments are limited by low adherence. We designed a novel digital therapeutic that modifies patient-selected cinematic content in real-time into therapeutic visual input, while objectively monitoring adherence. The therapeutic design integrated a custom-designed headset that delivers precise visual input to each eye, computational algorithms that apply real-time therapeutic modifications to source content, a cloud-based content management system that enables treatment in the home, and a broad library of licensed content. In a proof-of-concept human study on the therapeutic, we found that amblyopic eye vision improved significantly after 12 weeks of treatment, with higher adherence than that of available treatments. These initial results support the utility of personalized therapy in amblyopia and may have broader relevance for improving treatment outcomes in additional indications.
Ciliary neurotrophic factor (CNTF) is a leading therapeutic candidate for several ocular diseases and induces optic nerve regeneration in animal models. Paradoxically, however, although CNTF gene therapy promotes extensive regeneration, recombinant CNTF (rCNTF) has little effect. Because intraocular viral vectors induce inflammation, and because CNTF is an immune modulator, we investigated whether CNTF gene therapy acts indirectly through other immune mediators. The beneficial effects of CNTF gene therapy remained unchanged after deleting CNTF receptor alpha (CNTFRα) in retinal ganglion cells (RGCs), the projection neurons of the retina, but were diminished by depleting neutrophils or by genetically suppressing monocyte infiltration. CNTF gene therapy increased expression of C-C motif chemokine ligand 5 (CCL5) in immune cells and retinal glia, and recombinant CCL5 induced extensive axon regeneration. Conversely, CRISPR-mediated knockdown of the cognate receptor (CCR5) in RGCs or treating wild-type mice with a CCR5 antagonist repressed the effects of CNTF gene therapy. Thus, CCL5 is a previously unrecognized, potent activator of optic nerve regeneration and mediates many of the effects of CNTF gene therapy.
PURPOSE: Previous studies in patients with Alzheimer's disease have shown amyloid beta accumulation in the brain and abnormal brain activity, with mild cognitive impairment (MCI) in early stages of the disease. The aim of the current study was to investigate functional connectivity in patients with MCI. METHODS: We recruited 24 subjects in total, including 12 patients with MCI (6 men and 6 women) and 12 healthy controls (HCs) (6 men and 6 women), matched for age, gender, and lifestyle factors. All subjects underwent resting-state functional magnetic resonance imaging scans and voxel-wise degree centrality (DC) was used to evaluate alterations in the strength of brain network connectivity. RESULTS: The DC value of the left inferior temporal gyrus was lower in MCI but significantly higher in the right fusiform gyrus and the left supplementary motor area, compared with HCs. The DC value in left inferior temporal gyrus correlated positively with disease duration and negatively with Mini-Mental State Examination. ROC curve analysis of brain regions showed acceptable specificity and accuracy of DC values between MCIs and HCs in the area under the curve (right fusiform gyrus, 0.955; left supplementary motor area, 0.992; left inferior temporal gyrus, 1.000). CONCLUSIONS: Abnormal functional connectivity in brain regions of patients with MCI may reflect the pathological process of Alzheimer's disease development and could prove useful in clinical diagnosis and treatment.
The optic nerve conveys information about the outside world from the retina to multiple subcortical relay centers. Until recently, the optic nerve was widely believed to be incapable of re-growing if injured, with dire consequences for victims of traumatic, ischemic, or neurodegenerative diseases of this pathway. Over the past 10-20 years, research from our lab and others has made considerable progress in defining factors that normally suppress axon regeneration and the ability of retinal ganglion cells, the projection neurons of the retina, to survive after nerve injury. Here we describe research from our lab on the role of inflammation-derived growth factors, suppression of inter-cellular signals among diverse retinal cell types, and combinatorial therapies, along with related studies from other labs, that enable animals with optic nerve injury to regenerate damaged retinal axons back to the brain. These studies raise the possibility that vision might one day be restored to people with optic nerve damage.
A ring-enhancing lesion is an uncommon cause of a dorsal midbrain syndrome. Here, we describe the case of a 60-year-old man with eye movement and pupillary findings consistent with dorsal midbrain syndrome, and in whom neuroimaging showed a single ring-enhancing lesion in the right midbrain and thalamus. Further investigation revealed a longstanding right groin mass which proved to be a malignant melanoma. His intracranial lesion was presumed to be a metastatic lesion, and treated with stereotactic radiosurgery. We report the patient's clinical course, and discuss the diagnosis and management of the solitary midbrain lesion.
We describe 2 patients who developed postoperative orbital cerebrospinal fluid (CSF) collection after orbitozygomatic pterional craniotomy. An 18-year-old woman underwent exploratory pterional-orbitozygomatic craniotomy. Five days postoperatively, after removal of a lumbar drain, proptosis and a compressive optic neuropathy developed. Computed tomography demonstrated a CSF collection contiguous with the craniotomy site. Resolution followed percutaneous aspiration and replacement of the lumbar drain. A 57-year-old woman underwent a pterional-orbitozygomatic craniotomy for removal of a left anterior clinoid meningioma, complicated by a large left hemorrhagic stroke requiring decompressive hemicraniectomy. Extracranial CSF collections accumulated in both the orbit and subgaleal spaces. Resolution followed placement of an external ventricular drain. Based on these cases, the mechanism seems to be the combination of iatrogenic formation of a communication with the subarachnoid space and elevated intracranial pressure. Resolution was achieved by normalizing intracranial pressure.
BACKGROUND/OBJECTIVES: REALITY is an international observational retrospective registry of LHON patients evaluating the visual course and outcome in Leber hereditary optic neuropathy (LHON). SUBJECTS/METHODS: Demographics and visual function data were collected from medical charts of LHON patients with visual loss. The study was conducted in 11 study centres in the United States of America and Europe. The collection period extended from the presymptomatic stage to at least more than one year after onset of vision loss (chronic stage). A Locally Weighted Scatterplot Smoothing (LOWESS) local regression model was used to analyse the evolution of best-corrected visual acuity (BCVA) over time. RESULTS: 44 LHON patients were included; 27 (61%) carried the m.11778G>A ND4 mutation, 8 (18%) carried the m.3460G>A ND1 mutation, and 9 (20%) carried the m.14484T>C ND6 mutation. Fourteen (32%) patients were under 18 years old at onset of vision loss and 5 (11%) were below the age of 12. The average duration of follow-up was 32.5 months after onset of symptoms. At the last observed measure, mean BCVA was 1.46 LogMAR in ND4 patients, 1.52 LogMAR in ND1 patients, and 0.97 LogMAR in ND6 patients. The worst visual outcomes were reported in ND4 patients aged at least 15 years old at onset, with a mean BCVA of 1.55 LogMAR and no tendency for spontaneous recovery. The LOESS modelling curve depicted a severe and permanent deterioration of BCVA. CONCLUSIONS: Amongst LHON patients with the three primary mtDNA mutations, adult patients with the m.11778G>A ND4 mutation had the worst visual outcomes, consistent with prior reports.
Whole-brain networks derived from diffusion tensor imaging (DTI) data require the identification of seed and target regions of interest (ROIs) to assess connectivity patterns. This study investigated how initiating tracts from gray matter (GM) or white matter (WM) seed ROIs impacts (1) structural networks constructed from DTI data from healthy elderly (control) and individuals with Alzheimer's disease (AD) and (2) between-group comparisons using these networks. DTI datasets were obtained from the Alzheimer's disease Neuroimaging Initiative database. Deterministic tractography was used to build two whole-brain networks for each subject; one in which tracts were initiated from WM ROIs and another in which they were initiated from GM ROIs. With respect to the first goal, in both groups, WM-seeded networks had approximately 400 more connections and stronger connections (as measured by number of streamlines per connection) than GM-seeded networks, but shared 94% of the connections found in the GM-seed networks. With respect to the second goal, between-group comparisons revealed a stronger subnetwork (as measured by number of streamlines per connection) in controls compared to AD using both WM-seeded and GM-seeded networks. The comparison using WM-seeded networks produced a larger (i.e., a greater number of connections) and more significant subnetwork in controls versus AD. Global, local, and nodal efficiency were greater in controls compared to AD, and between-group comparisons of these measures using WM-seeded networks had larger effect sizes than those using GM-seeded networks. These findings affirm that seed location significantly affects the ability to detect between-group differences in structural networks.
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.
Superior oblique myokymia (SOM) is a rare condition of unclear etiology. We discuss the history, etiology, clinical features, differential diagnoses, management and prognosis of SOM. We conducted a meta-analysis of all 116 cases published since SOM was first described in 1906. The age at examination was 17-72 years (mean 42 years.) There was a right-sided preponderance in 61% of cases (P < 0.02) that was statistically significant in females (63%, P < 0.04) but not in males (59%, P = 0.18). The pathophysiology of SOM may be neurovascular compression and/or ephaptic transmission. Although various pharmacological and surgical approaches to SOM treatment have been proposed, the rarity of the condition has made it impossible to conduct clinical trials evaluating the safety and efficacy of these approaches. Recently, topical beta-blockers have managed SOM symptoms in a number of cases, including the first case treated with levobunolol. Systemic medications, strabismus surgery, and neurosurgery have been used to control symptoms, with strabismus surgery carrying a moderate risk of post-operative diplopia in down-gaze. While there is no established treatment for SOM, we encourage clinicians to attempt topical levobunolol therapy before considering systemic therapy or surgery.