Non-glaucomatous optic nerve atrophy (ONA) is a polyetiological pathological condition characterized by the loss of retinal ganglion cell axons and structural changes in the optic nerve head. ONA is one of the leading causes of irreversible visual impairment and disability across different age groups. This review presents current data on the epidemiology, clinical and demographic characteristics, pathogenesis, classification, diagnosis, treatment, and prognosis of ONA.

This study aimed to investigate the clinical factors, including neutrophil-to-lymphocyte ratio (NLR) and the initial House-Brackmann (H-B) grade, associated with electroneurography (ENoG) in patients with early-stage Bell's palsy. This retrospective cohort study evaluated 97 adults (≥18 years) with early-stage Bell's palsy diagnosed at our university hospital between January 2014 and September 2021. The medical records of these patients, including the NLR and the initial H-B grade, were reviewed. The degree of axonal loss was calculated using the compound muscle action potential (CMAP) amplitude ratio measured by ENoG. Patients were classified into 2 groups based on the degree of axonal loss: poor and good results, defined as >90% loss of amplitude (ENoG results < 10%) and ≤90% loss of amplitude (ENoG results ≥ 10%), respectively. Multivariable analysis revealed that an initial H-B grade II-III (odds ratio [OR], 4.79; 95% confidence interval [CI], 1.39-16.46) and an NLR < 1.92 (OR, 5.54; 95% CI, 1.85-16.53) were associated with good ENoG results. In our construction of a classification and regression tree (CART) model that considered various variables to predict the degree of axonal loss, the first partitioning node was initial H-B grade II, and CART analysis with minimal classification error found that an NLR of 1.61 was the second partitioning predictor. The model showed a sensitivity, specificity, and an accuracy of 87.5%, 80%, and 85.6%, respectively. By measuring the NLR at the time of Bell's palsy onset and initial facial weakness evaluated by H-B grade, it may be possible to predict subsequent axonal loss calculated by ENoG, which is performed 10 to 14 days after symptom onset.

See-saw nystagmus (SSN), and the possibly related hemi-see-saw nystagmus (hSSN), occur in certain forms of visual loss and in some brainstem lesions. These disparate lesions have made it challenging for investigators to arrive at a unified mechanism. Here we propose a model involving detection of peripheral retinal disparity in the superior colliculi (SC), which send inhibitory projections to the interstitial nucleus of Cajal (INC) that maintain calibration, and how loss of such calibration may provoke INC neurons (which are already mutually inhibitory with contralateral INC neurons) to develop self-inhibitory axo-dendritic autapses, resulting in a network configuration from which a pathologic Matsuoka oscillator can emerge and drive the alternating vertical and torsional movements characteristic of SSN and hSSN.

Nystagmus, the involuntary rhythmic oscillation of the eyes, is a critical diagnostic marker in vestibular medicine, distinguishing life-threatening central disorders such as stroke from benign peripheral conditions including Benign Paroxysmal Positional Vertigo (BPPV). Despite its clinical importance, accurate nystagmus assessment has long been constrained by expensive infrared video-oculography equipment such as videonystagmography, specialist dependency, and the episodic nature of vestibular symptoms that are often resolved before a clinical encounter. This review synthesizes approximately 50 papers published between 1952 and 2026 across four thematic domains: AI-driven nystagmus analysis, clinical medicine, smartphone and portable hardware innovations, and telemedicine and remote monitoring. On the AI front, classical machine learning models achieve up to 98.77% nystagmus recognition accuracy using ensemble methods, while deep learning frameworks spanning CNNs, U-Nets, LSTMs, and optical flow networks demonstrate clinical-grade slow-phase velocity measurement equivalent to gold standard video-oculography on standard smartphone RGB video. Large language and vision models including GPT-4V and Gemini 2.0 show early-stage promise as zero-shot triage tools but currently fall well below specialist-level diagnostic accuracy. Concurrently, portable hardware innovations ranging from 3D-printed goggle systems to ARKit-based smartphone applications are narrowing the accessibility gap, while telemedicine frameworks enable ictal recording and cloud-based specialist review outside the clinic. Across all domains, the common barriers to clinical translation are dataset scarcity for rare BPPV subtypes, sensitivity to ambient conditions, and the absence of explainable AI mechanisms. This review maps the current state of the field and identifies multimodal data fusion, prospective clinical validation, and interpretable AI as the critical next steps toward equitable, specialist independent vestibular diagnostics.

Background and Objectives: Non-invasive biomarkers reflecting neurodegeneration are increasingly important in multiple sclerosis (MS). Optical coherence tomography (OCT) provides quantitative measures of retinal structure, most commonly peripapillary retinal nerve fiber layer (pRNFL) thickness. However, the potential clinical relevance of optic nerve head morphology, including cup-to-disc ratio (CDR), remains insufficiently explored. We investigated associations between OCT-derived parameters, subjective visual vertical (SVV), and disability in MS. Materials and Methods: In this retrospective study, 100 patients with MS were included. OCT parameters (pRNFL thickness and area-based CDR) were analyzed at baseline and follow-up. Clinical disability was assessed using the Expanded Disability Status Scale (EDSS). Detailed optic neuritis history was not consistently available in the retrospective clinical records and therefore could not be systematically accounted for in the analyses. SVV was evaluated in 37 patients using a virtual reality-based protocol. Associations were assessed using Spearman correlation and linear regression analyses. Multivariable regression models were adjusted for age, sex, and follow-up duration. Results: pRNFL thickness was not associated with baseline EDSS (rho = -0.06, p = 0.55) or annualized EDSS change. Baseline CDR correlated with both baseline EDSS (rho = 0.30, p = 0.0065) and follow-up EDSS (rho = 0.46, p < 0.0001). In univariable regression analysis, baseline CDR was associated with follow-up EDSS (B = 3.33, R[2] = 0.23, p < 0.0001), remaining significant after adjustment for age, sex, and follow-up duration (B = 2.59, 95% CI 1.26-3.92, p = 0.0002). No significant associations were observed between OCT parameters and SVV measures. Conclusions: Higher CDR values, but not pRNFL thickness, were associated with disability measures in this exploratory MS cohort. However, these findings should be interpreted cautiously because optic neuritis history could not be systematically accounted for and physiological optic disc variability may substantially influence CDR measurements.

Trigeminal neuralgia (TN) ranks among the most excruciating neuropathic pain syndromes, characterized clinically by multiple daily episodes of unilateral, paroxysmal, electric shock-like facial pain. The daily activities and quality of life of affected patients are profoundly diminished. First-line pharmacological agents, such as carbamazepine and oxcarbazepine, provide initial relief for many patients. However, a significant proportion eventually develops refractory symptoms or experience intolerable adverse effects, leading to the discontinuation of traditional oral medications. For these patients with complex clinical phenotypes who fail to respond or are intolerant to these therapies, alternative pharmacological strategies are required before considering invasive surgical procedures. Over the past two decades, botulinumtoxin type-A (BoNTA) has become an effective and safe, minimally invasive therapeutic option for refractory TN. This review provides a practical framework for BoNTA use in the clinical setting of refractory TN. To connect the pathophysiological background with clinical patient care, we summarize the current understanding of TN pathophysiology, the proposed mechanisms by which BoNTA exerts its antinociceptive effects and the evolving clinical evidence supporting its efficacy and safety. We also critically examine dosing protocols, injection techniques, long-term outcomes and the integration of BoNTA into the management algorithm of refractory TN.

Typhus (FBT), caused by Rickettsia typhi, rarely causes neurological disease. Herein, we describe neurological involvement in two cases of FBT. In the first case, an adult presented with persistent fever which deteriorated into status epilepticus. He was successfully treated with doxycycline and made a complete recovery. In the second case, a patient suffered an ischemic stroke and had a protracted clinical course but ultimately made a near complete recovery. In addition to these cases, we conducted a comprehensive narrative review of 43 cases of neurologic involvement in FBT reported from 1989 to 2025. Cases were excluded if there were pathologic discrepancies with typical cases of FBT. Presentations ranged from cranial nerve palsies to meningitis and fulminant encephalitis. This review highlights the spectrum of CNS complications associated with FBT and underscores the importance of early recognition and treatment with doxycycline to improve outcomes. Given the potential severity of neurologic involvement, clinicians in endemic areas should maintain a high index of suspicion for FBT in patients presenting with a febrile illness and neurologic symptoms.

Bilateral sequential vestibular neuritis is a rare condition reported in literature involving the vestibular nerve sequentially. Nowadays, the video head impulse test (vHIT) and vestibular-evoked myogenic potentials provide specific patterns of reduced vestibulo-ocular reflex (VOR) that allow differentiation between complete and partial nerve involvement. These tests are essential in cases of bilateral vestibular loss to monitor vestibular compensation. The case of a 56-year-old man who presented to a tertiary vestibular center with acute left-sided vestibular loss, following a documented contralateral acute vestibular loss 4 years earlier. To the best of current knowledge, this report presents, for the first time in the literature, vHIT in Suppression Head Impulse Paradigm modality data as an expression of compensation. A review of the literature was also performed according to PRISMA statements.