CAD-Related Disorder (EIEE-50) in an Infant With Cortical Visual Impairment.

PURPOSE: To document the association of CAD-related disorder (EIEE-50) with cortical visual impairment. OBSERVATIONS: An 8-month-old Caucasian boy with whole genome sequencing confirming 2 variants in the gene CAD, who presented with severe seizures, microcephaly, hyperreflexia, hypotonia, anemia, and severe cortical visual impairment. Magnetic resonance imaging (MRI) of the brain noted thickened cortical gray matter along the right calcarine fissure as well as changes suggesting malformation of cortical development. Empiric uridine monophosphate supplementation has significantly improved seizure activity, hypotonia, and development and has led to resolution of anemia. CONCLUSIONS AND IMPORTANCE: CAD-related disorder is treatable and may affect visual cortical development causing severe secondary cortical visual impairment, a newly described clinical manifestation.

A Comparative Study of Large Language Models, Human Experts, and Expert-Edited Large Language Models to Neuro-Ophthalmology Questions.

BACKGROUND: While large language models (LLMs) are increasingly used in medicine, their effectiveness compared with human experts remains unclear. This study evaluates the quality and empathy of Expert + AI, human experts, and LLM responses in neuro-ophthalmology. METHODS: This randomized, masked, multicenter cross-sectional study was conducted from June to July 2023. We randomly assigned 21 neuro-ophthalmology questions to 13 experts. Each expert provided an answer and then edited a ChatGPT-4-generated response, timing both tasks. In addition, 5 LLMs (ChatGPT-3.5, ChatGPT-4, Claude 2, Bing, Bard) generated responses. Anonymized and randomized responses from Expert + AI, human experts, and LLMs were evaluated by the remaining 12 experts. The main outcome was the mean score for quality and empathy, rated on a 1-5 scale. RESULTS: Significant differences existed between response types for both quality and empathy (P < 0.0001, P < 0.0001). For quality, Expert + AI (4.16 ± 0.81) performed the best, followed by GPT-4 (4.04 ± 0.92), GPT-3.5 (3.99 ± 0.87), Claude (3.6 ± 1.09), Expert (3.56 ± 1.01), Bard (3.5 ± 1.15), and Bing (3.04 ± 1.12). For empathy, Expert + AI (3.63 ± 0.87) had the highest score, followed by GPT-4 (3.6 ± 0.88), Bard (3.54 ± 0.89), GPT-3.5 (3.5 ± 0.83), Bing (3.27 ± 1.03), Expert (3.26 ± 1.08), and Claude (3.11 ± 0.78). For quality (P < 0.0001) and empathy (P = 0.002), Expert + AI performed better than Expert. Time taken for expert-created and expert-edited LLM responses was similar (P = 0.75). CONCLUSIONS: Expert-edited LLM responses had the highest expert-determined ratings of quality and empathy warranting further exploration of their potential benefits in clinical settings.

Appropriateness of Ophthalmology Recommendations From an Online Chat-Based Artificial Intelligence Model.

Objective: To determine the appropriateness of ophthalmology recommendations from an online chat-based artificial intelligence model to ophthalmology questions. Patients and Methods: Cross-sectional qualitative study from April 1, 2023, to April 30, 2023. A total of 192 questions were generated spanning all ophthalmic subspecialties. Each question was posed to a large language model (LLM) 3 times. The responses were graded by appropriate subspecialists as appropriate, inappropriate, or unreliable in 2 grading contexts. The first grading context was if the information was presented on a patient information site. The second was an LLM-generated draft response to patient queries sent by the electronic medical record (EMR). Appropriate was defined as accurate and specific enough to serve as a surrogate for physician-approved information. Main outcome measure was percentage of appropriate responses per subspecialty. Results: For patient information site-related questions, the LLM provided an overall average of 79% appropriate responses. Variable rates of average appropriateness were observed across ophthalmic subspecialties for patient information site information ranging from 56% to 100%: cataract or refractive (92%), cornea (56%), glaucoma (72%), neuro-ophthalmology (67%), oculoplastic or orbital surgery (80%), ocular oncology (100%), pediatrics (89%), vitreoretinal diseases (86%), and uveitis (65%). For draft responses to patient questions via EMR, the LLM provided an overall average of 74% appropriate responses and varied by subspecialty: cataract or refractive (85%), cornea (54%), glaucoma (77%), neuro-ophthalmology (63%), oculoplastic or orbital surgery (62%), ocular oncology (90%), pediatrics (94%), vitreoretinal diseases (88%), and uveitis (55%). Stratifying grades across health information categories (disease and condition, risk and prevention, surgery-related, and treatment and management) showed notable but insignificant variations, with disease and condition often rated highest (72% and 69%) for appropriateness and surgery-related (55% and 51%) lowest, in both contexts. Conclusion: This LLM reported mostly appropriate responses across multiple ophthalmology subspecialties in the context of both patient information sites and EMR-related responses to patient questions. Current LLM offerings require optimization and improvement before widespread clinical use.

Mechanisms for Positive Bielschowsky Head Tilt Testing in Horizontal Strabismus.

PURPOSE: To elucidate the induced effects of horizontal strabismus on the Bielschowsky Head Tilt Test (BHTT). DESIGN: Prospective clinical study. METHODS: Prospective analysis of BHTT testing in 85 patients with exotropia and 71 patients with esotropia who were examined in a strabismus clinic. RESULTS: Eighty-four of 85 patients with exotropia (98.82%) showed a positive BHTT with an induced hyperdeviation on the side of the tilt (to both sides in 67% and to one side in 32%). Fifty-seven of 71 patients with esotropia (80.2%) showed a positive BHTT with an induced hypodeviation on the side of the tilt (to both sides in 57.7% and to one side in 22.5%). These induced vertical deviations were greater in patients with larger horizontal deviations and in those with constant rather than intermittent deviations; however, they were not influenced by the presence or absence of associated primary oblique muscle overaction. CONCLUSIONS: Exotropia and esotropia produce hyperdeviations during BHTT testing, with a hyperdeviation on the side of the tilt observed in patients with exotropia, and hypotropia on the side of the tilt observed in patients with esotropia. These diametrical results are not attributable to any preexistent alteration of neurologic output inherent to these two forms of horizontal strabismus or to associated torsion. Rather, they arise directly from the altered anatomical positions of the two eyes, which cause the eyes to approximate their visual axes more closely to the vertical rectus muscles (in exotropia) and the oblique muscles (in esotropia), enabling the vertical actions of specific cyclovertical muscles to predominate in response to altered utricular output generated by the BHTT.

Nacc1 Mutation in Mice Models Rare Neurodevelopmental Disorder with Underlying Synaptic Dysfunction.

A missense mutation in the transcription repressor Nucleus accumbens-associated 1 (NACC1) gene at c.892C>T (p.Arg298Trp) on chromosome 19 causes severe neurodevelopmental delay ( Schoch et al., 2017). To model this disorder, we engineered the first mouse model with the homologous mutation (Nacc1+/R284W ) and examined mice from E17.5 to 8 months. Both genders had delayed weight gain, epileptiform discharges and altered power spectral distribution in cortical electroencephalogram, behavioral seizures, and marked hindlimb clasping; females displayed thigmotaxis in an open field. In the cortex, NACC1 long isoform, which harbors the mutation, increased from 3 to 6 months, whereas the short isoform, which is not present in humans and lacks aaR284 in mice, rose steadily from postnatal day (P) 7. Nuclear NACC1 immunoreactivity increased in cortical pyramidal neurons and parvalbumin containing interneurons but not in nuclei of astrocytes or oligodendroglia. Glial fibrillary acidic protein staining in astrocytic processes was diminished. RNA-seq of P14 mutant mice cortex revealed over 1,000 differentially expressed genes (DEGs). Glial transcripts were downregulated and synaptic genes upregulated. Top gene ontology terms from upregulated DEGs relate to postsynapse and ion channel function, while downregulated DEGs enriched for terms relating to metabolic function, mitochondria, and ribosomes. Levels of synaptic proteins were changed, but number and length of synaptic contacts were unaltered at 3 months. Homozygosity worsened some phenotypes including postnatal survival, weight gain delay, and increase in nuclear NACC1. This mouse model simulates a rare form of autism and will be indispensable for assessing pathophysiology and targets for therapeutic intervention.

Ocular Neuromyotonia: Clinical Features, Diagnosis, and Outcomes.

PURPOSE: The purpose of this study was to describe the clinical features, management, outcomes, and diagnostic pitfalls in a large series of patients with ocular neuromyotonia. DESIGN: Retrospective cohort. METHODS: Patients diagnosed with ocular neuromyotonia from January 1, 2004, through January 1, 2023, seen at one of the 3 Mayo Clinic sites in Rochester, MN, Scottsdale, AZ, and Jacksonville, FL, comprised the study population. We ascertained patients with ocular neuromyotonia through a search using the medical records database. Only patients with an observed episode of ocular neuromyotonia were included and the medical records were reviewed. The main outcome measures were clinical features and outcomes of patients with ocular neuromyotonia. RESULTS: Forty-two patients who were diagnosed with ocular neuromyotonia were included. The median age was 58 years (range, 16-80 years). A history of cranial radiation therapy was present in 39 patients (93%). The sixth cranial nerve was involved in 31 patients (74%). Bilateral disease was found in 2 patients (5%). The median time from onset of diplopia to diagnosis was 8 months (range, 1 month-25 years), with a high rate of initial misdiagnosis in 52%. Twenty of 42 patients (48%) were treated with oral medication, of whom 95% had significant improvement or resolution of symptoms. CONCLUSION: Prior cranial irradiation is the most common cause for ocular neuromyotonia, affecting the sixth cranial nerve most often. Although delayed and initial misdiagnosis is common, most patients show improved symptoms on medical treatment.

Infectious and Inflammatory Processes of the Orbits in Children.

Most primary orbital pathology in children is due to bacterial infection. Radiologists typically encounter these cases to evaluate for clinically suspected postseptal orbital involvement. Contrast-enhanced cross-sectional imaging is important for the detection and early management of orbital infection and associated subperiosteal/orbital abscess, venous thrombosis, and intracranial spread of infection. Benign mass-like inflammatory processes involving the pediatric orbit are rare, have overlapping imaging features, and must be distinguished from orbital malignancies.

Up-regulation of cholesterol synthesis pathways and limited neurodegeneration in a knock-in Sod1 mutant mouse model of ALS.

Amyotrophic lateral sclerosis (ALS) is a severe neurodegenerative disorder affecting brain and spinal cord motor neurons. Mutations in the copper/zinc superoxide dismutase gene ( SOD1 ) are associated with ∼20% of inherited and 1-2% of sporadic ALS cases. Much has been learned from mice expressing transgenic copies of mutant SOD1, which typically involve high-level transgene expression, thereby differing from ALS patients expressing one mutant gene copy. To generate a model that more closely represents patient gene expression, we created a knock-in point mutation (G85R, a human ALS-causing mutation) in the endogenous mouse Sod1 gene, leading to mutant SOD1 G85R protein expression. Heterozygous Sod1 G85R mutant mice resemble wild type, whereas homozygous mutants have reduced body weight and lifespan, a mild neurodegenerative phenotype, and express very low mutant SOD1 protein levels with no detectable SOD1 activity. Homozygous mutants exhibit partial neuromuscular junction denervation at 3-4 months of age. Spinal cord motor neuron transcriptome analyses of homozygous Sod1 G85R mice revealed up-regulation of cholesterol synthesis pathway genes compared to wild type. Transcriptome and phenotypic features of these mice are similar to Sod1 knock-out mice, suggesting the Sod1 G85R phenotype is largely driven by loss of SOD1 function. By contrast, cholesterol synthesis genes are down-regulated in severely affected human TgSOD1 G93A transgenic mice at 4 months. Our analyses implicate dysregulation of cholesterol or related lipid pathway genes in ALS pathogenesis. The Sod1 G85R knock-in mouse is a useful ALS model to examine the importance of SOD1 activity in control of cholesterol homeostasis and motor neuron survival. SIGNIFICANCE STATEMENT: Amyotrophic lateral sclerosis is a devastating disease involving the progressive loss of motor neurons and motor function for which there is currently no cure. Understanding biological mechanisms leading to motor neuron death is critical for developing new treatments. Using a new knock-in mutant mouse model carrying a Sod1 mutation that causes ALS in patients, and in the mouse, causes a limited neurodegenerative phenotype similar to Sod1 loss-of-function, we show that cholesterol synthesis pathway genes are up-regulated in mutant motor neurons, whereas the same genes are down-regulated in transgenic SOD1 mice with a severe phenotype. Our data implicate dysregulation of cholesterol or other related lipid genes in ALS pathogenesis and provide new insights that could contribute to strategies for disease intervention.

Ocular Torsional Instability-A Neurodiagnostic Sign of Prenuclear Disease.

BACKGROUND: Accurate diagnosis of efferent visual system disease in neuro-ophthalmology involves the classification of clinical signs as prenuclear, nuclear, or infranuclear in origin. Over many years, I have come to recognize ocular torsional instability as a clinical sign of prenuclear disease. METHODS: Retrospective chart review of patients in whom ocular torsional instability was diagnosed using indirect ophthalmoscopy. RESULTS: Twenty patients were diagnosed as having ocular torsional instability (OTI). Eight had neuro-ophthalmologic disease caused by structural injury to prenuclear ocular motor areas. Six of these had structural lesions primarily involving the cerebellum, one had a midbrain glioma, and one had traumatic encephalomalacia. Eight additional patients had infantile strabismus (esotropia in 7, exotropia in 1) associated with various combinations of monocular nasotemporal optokinetic asymmetry, latent nystagmus, and dissociated vertical divergence (DVD), indicating prenuclear involvement of subcortical visuovestibular pathways within the brain. Three additional patients presented with intermittent exotropia with DVD signifying early onset, while 2 had acquired esotropia that was noninfantile in origin. One had partially accommodative esotropia with bilateral inferior oblique overaction, and one presented with acquired esotropia followed by spontaneous secondary exotropia. CONCLUSIONS: OTI provides a useful clinical sign of prenuclear ocular motor dysfunction. When detected in patients without any signs of infantile or early-onset strabismus, OTI signifies the need for neuroimaging to rule out neurovestibular or cerebellar causes of prenuclear disease.

Identification of AFG3L2 dominant optic atrophy following reanalysis of clinical exome sequencing.

Purpose: To highlight the importance of the utility of clinical exome sequencing, and show how it led to the diagnosis of nonsyndromic autosomal dominant optic atrophy arising from an autosomal dominant variant in AFG3L2. Observations: A healthy father and daughter of East African heritage experienced the onset of vision loss in the first decade of life due to optic atrophy. No additional neurologic or neuroimaging abnormalities were detected. Clinical exome sequencing was initially performed and provided a negative result. Reanalysis of the sequencing data revealed an autosomal dominant pathogenic variant in AFG3L2, c.1064C>T (p.Thr355Met), a gene that was recently identified to be associated with non-syndromic optic atrophy. This variant has previously been reported in a patient with optic atrophy, motor disturbances, and an abnormal brain MRI. Conclusions: As the causes of dominant optic atrophy continue to expand, accurate genetic diagnosis is aided by an iterative reanalysis process for individuals and families when initial exome and genome testing does not provide an answer.

Alström syndrome caused by maternal uniparental disomy.

Purpose: To describe a case of Alström syndrome arising from maternal uniparental disomy. Observations: A 13-month-old boy with poor vision and nystagmus was diagnosed with Alström syndrome based on genetic testing that identified a homozygous pathogenic variant, ALMS1 c.2141_2141del (p.Ser714Tyrfs*6), that was only found in his mother and not his father. In contrast to the usual autosomal recessive inheritance pattern in which a child inherits a variant from each parent, multi-step genetic testing of the child and both parents confirmed uniparental disomy as the mechanism of inheritance. Conclusions and Importance: Confirmation of uniparental disomy in autosomal recessive disorders allows for parental assurance that future offspring will be unaffected.

Escape from prism.

A 14-year-old boy with a history of shunted congenital hydrocephalus began having headaches with nausea and vomiting after transcontinental flights. He gradually developed horizontal diplopia indicative of mild bilateral sixth nerve palsy, without papilledema or ventriculomegaly. Intracranial pressure monitoring showed no signs of elevation. After he subsequently developed papilledema, surgical exploration showed shunt malfunction, and shunt replacement produced rapid resolution of symptoms. This case demonstrates the importance of relying on clinical history and neuro-ophthalmologic examination in patients with hydrocephalus and suspected shunt failure, even when objective confirmatory evidence of intracranial pressure elevation is lacking.

A high-pressure situation.

An 8-year-old boy presented with acute visual loss in the right eye and nausea, vomiting, and diplopia. Imaging revealed a right orbital apex mass. Biopsy showed Langerhans cell histiocytosis (LCH), and the patient was diagnosed with isolated orbital LCH causing an orbital apex syndrome. A 12-month cytarabine chemotherapy course was begun, during which the patient developed bilateral optic disc edema. He was diagnosed with cytarabine-induced intracranial hypertension, which was successfully treated with acetazolamide. The cytarabine course was completed with complete resolution of the LCH lesion. The ophthalmologic relevance of this rare disorder is discussed.

Temporal Slant Recession of the Inferior Rectus Muscle: A Simple Surgical Treatment for Diplopia Caused by Small Vertical Deviations.

BACKGROUND: To evaluate the therapeutic effect of temporal slant recession of the inferior rectus muscle (TSRIRM) for the treatment of small vertical deviations in patients with vertical diplopia, with consideration of the theoretical additive effects of this procedure on ocular torsion and horizontal incomitance. METHODS: Retrospective review of 11 patients who were treated with TSRIRM. Eight patients with vertical diplopia and small hyperdeviations (up to 6 prism diopters (PDs)) were treated with isolated TSRIRMs. Three patients with vertical diplopia from unilateral superior oblique palsies with large hyperdeviations (>15 PDs) were treated with TSRIRMs in conjunction with contralateral inferior oblique recessions. RESULTS: Six of the 8 patients with small vertical deviations had successful vertical realignment with elimination of symptomatic diplopia after an isolated TSRIRM. Two of the eight patients had residual hypertropia with symptomatic diplopia. Three additional patients with unilateral superior oblique palsy had successful vertical realignment with elimination of symptomatic diplopia after ipsilateral inferior oblique recession and contralateral TSRIRM. In total, 9 of 11 patients had successful surgical results after TSRIRM. CONCLUSIONS: TSRIRM provides an effective and reliable treatment for small angle vertical strabismus. Its ease of surgical access renders it useful for implementation in an outpatient neuro-ophthalmology setting.

Interprofessional Electronic Consultations for the Diagnosis and Management of Neuro-Ophthalmic Conditions.

BACKGROUND: Interprofessional electronic consultation (eConsult) is a telemedicine modality in which consulting providers review outside records and provide recommendations without in-person consultation. The purpose of this study was to describe the utilization of eConsults in the management of neuro-ophthalmic conditions. METHODS: Retrospective cohort study of all patients who received an eConsult for a neuro-ophthalmic condition at a single quaternary referral center from 2018 to 2020. Main outcome measures included proportion of eConsults in which sufficient data were provided to the neuro-ophthalmologist to generate a definitive management decision, proportion of patients for whom an in-person neuro-ophthalmology evaluation was recommended, and the eConsult's impact on patient care. RESULTS: Eighty eConsults were conducted on 78 patients during the 3-year study period. Forty-eight (60.0%) subjects were female, mean age was 54 years, and 65 (81.3%) were White. The median time from eConsult request to completion was 4 days (range: 0-34 days). The most frequent eConsult questions were vision/visual field disturbances in 28 (35.0%) cases, optic neuropathies in 22 (27.5%), and optic disc edema in 17 (21.3%). At the time of eConsult, sufficient prior information was provided in 35 (43.8%) cases for the neuro-ophthalmologist to provide a definitive management decision. In 45 (56.3%) eConsults, further diagnostic testing was recommended. In-person neuro-ophthalmology consultation was recommended in 24 (30.0%) cases. Sixty-one (76.3%) eConsults provided diagnostic and/or treatment direction, and 12 (15.0%) provided reassurance. CONCLUSION: eConsults increase access to timely neuro-ophthalmic care and provide diagnostic and treatment direction to non-neuro-ophthalmology providers when sufficient information is provided at the time of eConsult.

CRISPR/Cas9-mediated excision of ALS/FTD-causing hexanucleotide repeat expansion in C9ORF72 rescues major disease mechanisms in vivo and in vitro.

A GGGGCC24+ hexanucleotide repeat expansion (HRE) in the C9ORF72 gene is the most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), fatal neurodegenerative diseases with no cure or approved treatments that substantially slow disease progression or extend survival. Mechanistic underpinnings of neuronal death include C9ORF72 haploinsufficiency, sequestration of RNA-binding proteins in the nucleus, and production of dipeptide repeat proteins. Here, we used an adeno-associated viral vector system to deliver CRISPR/Cas9 gene-editing machineries to effectuate the removal of the HRE from the C9ORF72 genomic locus. We demonstrate successful excision of the HRE in primary cortical neurons and brains of three mouse models containing the expansion (500-600 repeats) as well as in patient-derived iPSC motor neurons and brain organoids (450 repeats). This resulted in a reduction of RNA foci, poly-dipeptides and haploinsufficiency, major hallmarks of C9-ALS/FTD, making this a promising therapeutic approach to these diseases.