Ocular Motor Cranial Nerve Palsies Research Articles

Cranial Nerve Palsy and Risk of Kidney Cancer: A Nationwide Population-Based Study.

Background and Objective: Understanding whether cranial nerve palsy (CNP) acts as an independent risk factor for kidney cancer could have important implications for patient care, early detection, and potentially the development of preventive strategies for this type of cancer in individuals with CNP. This study aimed to examine the risk of kidney cancer following the onset of ocular motor CNP and assess whether CNP could be considered an independent risk factor for kidney cancer. Materials and Methods: A population-based cohort study was conducted using data from the National Sample Cohort (NSC) database of Korea's National Health Insurance Service which was collected from 2010 to 2017. Follow-up was until kidney cancer development, death, or 31 December 2018. Cox proportional hazard regression analysis was performed to determine hazard ratios (HRs) for kidney cancer according to CNP status. Participants aged 20 years or more diagnosed with CNP from 2010 to 2017 were included. Exclusions comprised individuals with specific pre-existing conditions, inability to match a control group, and missing data, among others. CNP patients were age-sex matched in a 1:5 ratio with control cases. The primary outcome was incidence of kidney cancer during the follow-up period. Results: This study comprised 118,686 participants: 19,781 in the CNP group, and 98,905 in the control group. Compared to the control group, participants with CNP had a higher risk of kidney cancer (adjusted HR in model 4, 1.599 [95% CI, 1.116-2.29]). After a 3-year lag period, the CNP group had a significantly higher risk (adjusted HR in model 4, 1.987 [95% CI, 1.252-3.154]). Conclusions: Ocular motor CNP may be an independent risk factor for kidney cancer, as indicated by a higher incidence of kidney cancer in CNP patients. Further research is needed to elucidate the underlying mechanisms and explore potential preventive measures for kidney cancer in patients with ocular motor CNP.

Proteinuria and risk of ocular motor cranial nerve palsy: a nationwide population-based study

Understanding the association between dipstick-detected proteinuria and oculomotor cranial nerve palsy (CNP) could have significant implications for understanding the mechanism of CNP development and for developing preventive strategies against CNP development in patients with proteinuria. This study aimed to determine the relationship between dipstick-determined proteinuria and ocular motor CNP using National Sample Cohort (NSC) database from Korea’s National Health Insurance Service (NHIS). A nationwide population-based cohort study was conducted using data from the NSC database of Korea’s NHIS. These data were collected from 2009 to 2018. A one-year time lag was established to prevent a situation in which the causal link was inverted. Participants aged 20 years or more who were diagnosed with proteinuria in 2009 were included. Individuals with specific pre-existing CNP, missing data, and those who were newly diagnosed with CNP or who died within one year of being tested were excluded. The study population was classified into six groups according to the degree of proteinuria (negative, trace, or between 1 + and 4 +) based on the urine dipstick test. A Cox proportional hazard regression analysis was performed to determine the linkage between the degree of proteinuria and ocular motor CNP. A total of 5,807 (0.14% of subjects) with ocular motor CNP were assigned to the ocular motor CNP group and 4,047,205 subjects were assigned to the control group. After full adjustment of comorbidities, hazard ratios (HRs) for 1 + , 2 + , 3 + and 4 + proteinuria groups were 1.449 (95% confidence interval [CI] 1.244–1.687), 2.081 (1.707–2.538), 1.96 (1.322–2.904), and 3.011 (1.507–6.014), respectively, for developing ocular motor CNP compared to the proteinuria-negative group. In subgroup analysis, the HR of patients with proteinuria for the development of ocular motor CNP was higher in the younger age group (less than 40 years) (P = 0.0242) and the group with DM (P = 0.04). Our population-based cohort study demonstrated a significant association between proteinuria and the incidence of CNP, suggesting that urine protein level could be a new clinical marker for predicting the development of CNP.

The Etiology of Paralytic Strabismus at an Indonesian Tertiary Hospital from 2017 to 2022

Highlights: 1. This study investigated the etiology of paralytic strabismus, a condition that requires further research to prevent its incidence, particularly in adults.2. The findings of this study provided valuable insight into the primary etiology of paralytic strabismus and its underlying factors. Abstract Paralytic strabismus is the most common cause of adult-onset strabismus. It can result from paralysis of the third, fourth, or sixth cranial nerves, either separately or in combination, which are responsible for innervating the ocular motor muscles. Paralysis of these cranial nerves occurs due to congenital disorders, neoplasms, trauma, intracranial processes, idiopathic diseases, and other causes. This study aimed to determine the etiology of paralytic strabismus incidence at the Department of Ophthalmology of Dr. Soetomo General Academic Hospital, Surabaya, Indonesia, between 2017 and 2022. This study employed a retrospective methodology and utilized total sampling. The medical records of patients diagnosed with paralytic strabismus were used to collect secondary data. Out of the total of 282 cases, the most common condition was combined ocular motor cranial nerve palsy, which accounted for 102 (36.2%) cases. The main factors contributing to this condition were neoplasms (37.2%), intracranial processes (25.5%), trauma (25.5%), other causes (8.8%), idiopathic diseases (2%), and congenital disorders (1%). The incidence of third cranial nerve palsy and sixth cranial nerve palsy was equally prevalent, each accounting for 86 (30.5%) cases. Meanwhile, fourth cranial nerve palsy was the least frequent with just eight (2.8%) cases. This study concluded that the most frequent etiology of paralytic strabismus was combined ocular motor nerve paralysis, which primarily results from neoplasms.

Abducens Nerve Duplication: Novel Intraoperative and Radiographic Observation of a Rare Anatomical Variant

Abstract Objectives The abducens nerve has a long, serpentine subarachnoid course with complex topographical relationships, rendering abducens nerve palsy the most common ocular motor cranial nerve palsy in adults and second most common in pediatric patients, with anatomical variants reported in the literature. Preoperative awareness of abducens nerve variant anatomy may help prevent inadvertent intraoperative injury. Design This study is a case report with a review of the abducens nerve anatomy and variants. Setting The study setting included outpatient, inpatient, and operating room in the neurosurgery department of a quaternary referral center. Participants The study included a woman in her early 30s with a diagnosis of petrous meningioma. Main Outcome Measures In vivo documentation of a type 3 abducens nerve duplication was carried out. Results A left extended retrosigmoid craniotomy was recommended for the petroclival meningioma resection. Intraoperatively, a complete duplication of the left abducens cisternal segment was encountered and photographed. The left unilateral abducens nerve duplication was confirmed with postoperative volumetric magnetic resonance imaging using the FIESTA (fast imaging employing steady-state acquisition) sequence, revealing the union of the duplicated cisternal abducens nerves into a single trunk from Dorello's canal distally. Conclusions Abducens nerve variants are uncommon, and although reported in the setting of cadaveric dissection, in vivo documentation of them is limited. This case report of an in vivo type 3 abducens nerve duplication with intraoperative photographic and radiographic images highlights the need for clinical awareness to avoid inadvertent intraoperative injury.

Ocular Motor Cranial Nerve Palsies and Increased Risk of Primary Malignant Brain Tumors: South Korean National Health Insurance Data.

The aim of this study was to investigate the association between ocular motor cranial nerve palsies (OMCNP) and the occurrence of primary malignant brain tumors in a Korean population, using the national sample cohort database from Korea National Health Insurance Service (KNHIS). KNHIS data between 2010 and 2017 were analyzed. Our sample encompassed 118,686 participants, including 19,781 from a recently diagnosed OMCNP cohort and 98,905 from a matched control cohort through a 1:5 propensity score matching based on age and gender. To counteract the issue of reverse causation, we integrated a one-year time lag in our sensitivity analysis. Study participants were followed up until 31 December 2019. Cox proportional hazard regression analysis was used to compute the adjusted hazard ratio (HR) for primary malignant brain tumors according to the OMCNP diagnosis. Additionally, we performed a subgroup analysis to discern effects of various factors on the association between OMCNP and primary malignant brain tumors. HR for primary malignant brain tumors was 3.272 (95% confidence interval [CI]: 2.294 to 4.665) in the OMCNP cohort compared to the control cohort in a fully adjusted model for age, sex, socio-economic status, smoking, drinking, regular physical exercise, hypertension, diabetes, dyslipidemia, obesity, chronic kidney disease, and human immunodeficiency virus infection. Further subgroup analysis revealed that the risk of primary malignant brain tumors was significantly increased in women with OMCNP compared to men with OMCNP (HR: 5.118 in women vs. 2.441 in men, p = 0.0440), and in those aged <65 years than in those aged ≥65 years (HR: 6.951 in age < 65 years vs. 1.899 in age ≥ 65 years, p = 0.0006). Our population-based cohort study demonstrated a significantly increased risk of subsequent primary malignant brain tumors in patients with OMCNP. Particularly, OMCNP-afflicted women aged below 65 manifested a heightened probability of developing primary malignant brain tumors compared to those devoid of OMCNP.

Study of etiological profile of patients with paralytic strabismus in a tertiary care hospital in India: a cross-sectional study

Abstract Introduction: Paralytic strabismus, a type of strabismus caused by paralysis of one or more extraocular muscles, can lead to a variety of ocular and psychosocial sequelae. Etiology varies in different types of paralytic strabismus. Numerous studies have shown that ocular motor cranial nerve palsies have a variety of causes including vascular disease, head trauma, intracranial tumour or aneurysm and inflammatory disorders.Materials and Methods: A cross-sectional study was conducted at a tertiary eye hospital to evaluate Paralytic squint by Neuroimaging in patients presenting to the Squint department of Sarojini Devi Eye Hospital Hyderabad from June 2021 to May 2022. Paralytic strabismus cases with limitation of ocular motility were enrolled and a detailed examination was performed to know the etiology. Results: 190 patients (1.35%) were diagnosed with paralytic strabismus. Ischemia constituted to be the major cause of paralytic strabismus i.e. (42.1%) followed by trauma (20%). The 3rd cranial nerve was the most commonly involved (34.73%), followed by the 6th cranial nerve (32.63%). Multiple cranial nerves were involved in 20% of cases. The 3rd CN was involved, primarily due to ischemia in both males and females while the 6th CN was affected with trauma, neoplasm, and ischemia being prominent causes. Conclusion: The study showed that ischemia, trauma and idiopathy are some of the major etiologies of paralytic strabismus with male predominance. The cranial nerve involvement also varied with the etiology of paralytic strabismus.

Dynamic Changes in Metabolic Status Are Associated With Risk of Ocular Motor Cranial Nerve Palsies.

To investigate whether recovery from or development of metabolic syndrome (MetS) in a population is associated with an altered risk for ocular motor cranial nerve palsy (CNP). This cohort study included 4,233,273 adults without a history of ocular motor cranial nerve palsy (ocular motor CNP) who underwent 2 consecutive biennial health screenings provided by the Korean National Health Insurance System between 2009 and 2011. They were followed up until December 31, 2018. Participants were categorized into a MetS-free, MetS-developed, MetS-recovered, or MetS-chronic group. A multivariable Cox proportional hazard regression model was used. Model 3 was adjusted for age, sex, smoking status, alcohol consumption, and physical activity. Compared with the MetS-free group, the MetS-chronic group had the highest risk of ocular motor CNP (hazard ratio [HR]: 1.424; 95% confidential interval [CI]: 1.294-1.567, Model 3), followed by the MetS-developed group (HR: 1.198, 95% CI: 1.069-1.343), and the MetS-recovered group (HR: 1.168, 95% CI: 1.026-1.311) after adjusting for potential confounders. The hazard ratio of ocular motor CNP in men with chronic MetS was 1.566 (95% CI, 1.394-1.761) while that of women with chronic MetS was 1.191 (95% CI, 1.005-1.411). Among age groups, those in their 30s and 40s showed the highest association between dynamic MetS status and ocular motor CNP. In our study, recovering from MetS was associated with a reduced risk of ocular motor CNP compared with chronic MetS, suggesting that ocular motor CNP risk could be managed by changing MetS status.

Association between migraine and risk of ocular motor cranial nerve palsy

To assess association between migraines and development of ocular motor cranial nerve palsy (CNP) and finding risk factors using the National Sample Cohort database from the Korea National Health Insurance Service. Data was analyzed from 4,234,341 medical screening examinees aged 20–90 years in 2009. Cox proportional hazard regression analysis was used to the adjusted hazard ratios (HR) for ocular motor CNP according to presence of migraine. Subgroup analysis was performed to evaluate effect of other factors on association of migraine with ocular motor CNP. A total of 5806 participants (0.14% of subjects) developed ocular motor CNP and were assigned to CNP group, 4,048,018 were assigned to control group, with an average of 8.22 ± 0.93 years of follow-up. Incidence of ocular motor CNP increased in migraine group compared to control. After adjusting potential confounding variables, HR for ocular motor CNP was 1.166 (confidence interval [CI] 1.013–1.343) in migraine group. Subgroups of relatively younger age less than 65 years (HR = 1.267, 95% CI 1.067–1.504), male gender (HR = 1.228, 95% CI 1.000–1.122), smokers (HR 1.426, 95% CI 1.127–1.803), and diabetes mellitus patients (HR = 1.378, 95% CI 1.045–1.378) showed a stronger association between migraines and development of ocular motor CNP. Our population-based cohort study demonstrated a significant association between presence of migraines and incidence of ocular motor CNP. Especially, relatively younger age, males, smokers, and diabetes patients with migraines could have a higher risk of developing ocular motor CNP.

Spontaneous chronic subdural hematoma as the cause of oculomotor cranial nerve palsy: A narrative review.

Acute complete third nerve palsy with pupillary involvement is usually caused by a posterior communicating artery aneurysm (i.e. "the rule of the pupil"). The pupillary fibers run peripherally in the third nerve and are thus susceptible to the external compression. Headache is usually present, and urgent diagnosis and treatment are warranted. Rarely, however, neuroimaging shows other causes of third nerve palsy. In this study, we perform a literature review of spontaneous chronic subdural hematoma that, although rarely, may cause an acute pupil-involving third nerve palsy as a false localizing sign. We review the localizing, nonlocalizing, and false localizing nature of ocular motor cranial nerve palsy in this setting.

Liver enzymes and risk of ocular motor cranial nerve palsy: a nationwide population-based study.

This study aimed to assess the associations between liver enzymes including γ-glutamyl transferase (GGT) and the development of ocular motor cranial nerve palsy (CNP) using the National Sample Cohort database from Korea's National Health Insurance Service. We analyzed data from 4,233,273 medical screening examinees aged 20years or more in 2009. Study participants were followed up until December 31, 2018. A Cox proportional hazard regression analysis was performed for quartiles of liver enzymes to determine the linkage between each value and ocular motor CNP using quartile 1 as a reference after adjusting for potential confounders. A total of 5,807 (0.14%) patients developed ocular motor CNP during the follow-up period of 8.22 ± 0.94years. The incidence of ocular motor CNP gradually increased as the GGT levels increased. The highest quartile of the GGT group had hazard ratio (HR) of 1.245 (95% confidence interval [CI], 1.136-1.365). Regarding alanine aminotransferase (ALT), the highest quartile of the ALT group had HR of 1.141 (95% CI, 1.049-1.241). However, the incidence of ocular motor CNP did not gradually increase as the ALT levels increased. The coexistence of the increased level of GGT, metabolic syndrome, and obesity showed a stronger association with ocular motor CNP development (HR, 1.331; 95% CI, 1.173, 1.511) compared to having a single factor or two factors. In conclusion, our population-based cohort study demonstrated a significant association between serum GGT level and the incidence of ocular motor CNP, suggesting that GGT could be a new clinical marker for predicting the occurrence of ocular motor CNP.

Commentary: Pediatric ocular motor cranial nerve palsy: Demographics and etiological profile.

Commentary: Pediatric ocular motor cranial nerve palsy: Demographics and etiological profile.

Pediatric ocular motor cranial nerve palsy: Demographics and etiological profile.

Purpose:The aim of this study was to describe epidemiological and clinical characteristics of pediatric ocular motor cranial nerve palsy.Methods:This was a retrospective record-based study, carried out at a tertiary eye care hospital in India, between January 2011 and January 2015 and included patients up to 16 years of age at the time of presentation, diagnosed with third, fourth, sixth nerve palsy or a combination of these with other cranial nerve palsy. Data analyzed included demographic details, etiologies, presence or absence of amblyopia, relevant investigations, and management.Results:A total of 90 cases were included in the study. Eighty patients (88.88%) presented with isolated nerve palsy. Forty-three patients (47.77%) had congenital nerve palsy. The most common nerve involved was third (n = 35, 38.88%) followed by sixth (n = 23, 25.55%) and fourth nerve (n = 22, 24.44%). Most common cause of third and fourth cranial nerve palsy was congenital (n = 18, 51.42% and n = 17, 77.30%, respectively), while it was trauma for the sixth nerve (n = 7, 30.40%). Amblyopia was most frequently associated with third cranial nerve palsy (n = 27, 77.14%). The radio-imaging yield was maximum (n = 7, 70%) for combined cranial nerve palsy. Overall 44 (48.88%) patients were managed conservatively, while 46 (51.11%) patients needed squint with or without ptosis surgery.Conclusion:The most common ocular motor cranial nerve involved in the pediatric population was the third cranial nerve, and it was found to be the most amblyogenic in this age group. The neuroimaging yield was maximum for combined cranial nerve palsy. The most common conservatively managed nerve palsy in this study group was the fourth nerve palsy.

The Role of Neuro-Ophthalmologists in the Care of Patients With Neurofibromatosis Type 2.

Neurofibromatosis type 2 (NF2) is a rare genetic disorder, affecting the central nervous system and leading to various degrees of disability. Its hallmark is bilateral vestibular schwannomas that invariably lead to progressive hearing loss. Specific ophthalmic abnormalities in patients with NF2 may help to establish an early diagnosis. These include juvenile cataract, epiretinal membrane, combined hamartoma of the retina and the retinal pigment epithelium, optic disc glioma, and optic nerve sheath meningioma. In addition, intracranial tumors may produce a variety of neuro-ophthalmic abnormalities that have the potential to impair visual function, such as postpapilledema optic atrophy, compression of the visual pathways, keratopathy, ocular motor cranial nerve palsies, and amblyopia. Care of NF2 patients is best provided by interdisciplinary medical teams including a neuro-ophthalmologist.

Acute binocular diplopia: peripheral or central?

ObjectivesAcute diplopia is a diagnostic challenge for clinicians, in particular in the emergency department. The most common cause of acute diplopia are ocular motor nerve palsies (OMP). In this prospective study, we focused on identifying the most crucial signs and symptoms for differentiating between peripheral and central OMP.MethodsWe prospectively evaluated 56 non-consecutive patients who presented at our emergency department with acute binocular diplopia (≤ 10 days). The patient history was taken using a standardized questionnaire and patients underwent a neurological, neuro-ophthalmological and neuro-otological examination, including measurement of the subjective visual vertical (SVV), Harms tangent screen test, and cranial MRI.ResultsForty-six out of 56 patients were diagnosed with an ocular motor cranial nerve palsy (OMP), 21 of peripheral and 23 of central origin; in two patients, the etiology remained unknown. The following features were different in peripheral and central OMP: (1) the presence of vertigo/dizziness was more frequent in central (43.5%) than in peripheral (9.5%) OMP. (2) Central ocular motor signs, such as saccadic smooth pursuit, additional internuclear ophthalmoplegia, skew deviation, and saccade palsies, were also found more frequently in the central than in the peripheral group (86.7% vs. 33.3%). (3) Further, a pathological SVV deviation by monocular testing of the non-affected eye was also more common in central (77.3%) than in peripheral OMP (38.9%). The presence of all three factors has a positive predictive value of 100% (CI 50–100%) for the presence of a central lesion.ConclusionsIn acute diplopia due to central OMP, the most important accompanying symptom is vertigo/dizziness, and the most important clinical signs are central ocular motor disorders (which require examination of the non-paretic eye) and an SVV deviation in the non-paretic eye.

Ocular Motor Cranial Nerve Palsy as an Indicator of Neglected Systemic Disease in Nigeria: Perspective from a Neuro-Ophthalmology Clinic

ABSTRACTThe aim of this article from Nigeria is to draw attention to public health issues in medical care using ocular motor cranial nerve palsy (OMCNP) presenting to a neuro-ophthalmology clinic as a case study. All patients presenting with OMCNP between November 2007 and October 2016 were retrospectively reviewed. Demographic details as well as information regarding the clinical presentation, clinical course, investigation, and treatment outcomes were extracted from case records. Phone calls were made to the contact numbers of patients who had been lost to follow-up. Data were analysed using SPSS version 22 (IBM, Corp. Armonk, NY, USA). Cranial nerve palsies other than oculomotor, trochlear, and abducens palsies were excluded. Fifty-nine patients, comprising 28 males and 31 females, were identified. Age range was 1–84 years (median 43.0 ± 19.7 years). Fifty-one cases (93.2%) were mono neuropathies, while four (6.8%) affected multiple nerves. Oculomotor nerve palsy was most common, accounting for 57.6% of cases. Microvascular angiopathy was the commonest identifiable cause (25.6%). Aetiology was not identified in 16 cases. There were three (5.1%) deaths. Undiagnosed systemic disease appears to be a major risk factor for this patient group in this African setting. Patient investigation was problematic. Poor patient compliance and follow-up resulted in preventable deaths. Neuro-ophthalmologists practicing in low resource settings should be aware of these risks.

Risk of ischemic stroke after third, fourth, and sixth cranial nerve palsies in type 2 diabetes.

The aim of this study was to define the risk of ischemic stroke among newly diagnosed type 2 diabetes (T2D) patients who developed ocular motor cranial nerve (CN) palsies. From the National Health Insurance Service - National Sample Cohort database (2002-2013) of a random sample of 1 025 340 Koreans, patients with newly diagnosed T2D aged ≥20 years were included in the study. The incidence of ocular motor CN palsies was identified using diagnostic codes for third, fourth, and sixth CN palsies. To determine the effect of incident ocular motor CN palsy on subsequent ischemic stroke, covariate Cox regression was used (Model 1 included only ocular motor CN palsy as a time-varying covariate; Model 2 included ocular motor CN palsy and demographic information; Model 3 included all variables in Model 2 as well as comorbidity, concomitant medication, and the Charlson comorbidity index score). Of 45 820 T2D patients, 75 developed ocular motor CN palsy and 1411 had ischemic stroke. Four patients experienced ischemic stroke after the development of ocular motor CN palsy. Incident ocular motor CN palsy was associated with the subsequent risk of ischemic stroke in Models 1, 2 and 3 (hazard ratios [95% confidence intervals] 3.74 [1.40-9.98], 3.33 [1.25-8.89], and 2.96 [1.11-7.92], respectively). Male sex, older age, and lower income were associated with an increased risk of ischemic stroke. Among confounders, hypertension, atrial fibrillation, and congestive heart failure were associated with the risk of ischemic stroke. Physicians should pay more attention to manageable risk factors of ischemic stroke when diabetic patients suffer from ocular motor CN palsies.

Ocular motor cranial nerve palsy and increased risk of stroke in the general population.

PurposeTo determine whether ocular motor cranial nerve (CN) palsy raises the risk of subsequent stroke in the general population.MethodsWe investigated the association between ocular motor CN palsy and occurrence of stroke using the National Health Insurance Service-National Sample Cohort database from 2002 to 2013. We included individuals aged ≥ 20 years on January 1st, 2004, and excluded those having any paralytic strabismus, disorders in binocular movement, diplopia and any cerebrovascular diseases before entering the cohort. Incident ocular motor CN palsy was identified by diagnostic codes for third, fourth, and sixth nerve palsies. To determine the effect of incident ocular motor CN palsy on the occurrence of subsequent stroke, we used time-varying covariate Cox regression models. Model 1 included only incident third, fourth, and sixth nerve palsies as a time-varying covariate. Model 2 included Model 1 and defined demographic information. Model 3 included Model 2, comorbidity, co-medication, and the Charlson index score.ResultsAmong 727,689 individuals in the cohort, 1,633 patients developed ocular motor CN palsy and 17,657 patients suffered stroke. Cox regression models showed that development of ocular motor CN palsy was associated with an increased risk of subsequent stroke (hazard ratio [HR] = 4.65; 95% confidence intervals [CIs], 3.74–5.80 in Model 1), and the results were consistent even after adjusting for demographic factors and confounders in Model 2 and 3. Men, older age, and individuals not living in Seoul/Incheon area were associated with an increased risk of stroke, while individuals with higher income were associated with decreased risk of stroke in both Model 2 and 3. Sensitivity analyses using propensity score-based matching produced similar results in all three Models (HR = 1.95; 95% CI, 1.55–2.46 in Model 1, HR = 1.91; 95% CI, 1.52–2.41 in Model 2, and HR = 1.63; 95% CI, 1.29–2.06 in Model 3).ConclusionsThe occurrence of ocular motor CN palsy is a significant risk factor of subsequent stroke even after adjusting for demographic factors and confounders in the general population. Physicians may need to educate patients with ocular motor CN palsy regarding the higher risk of future stroke.

High-Resolution 3D Magnetic Resonance Imaging of the Sixth Cranial Nerve: Anatomic and Pathologic Considerations by Segment.

Weakness of the sixth cranial nerve is the most common cause of an ocular motor cranial nerve palsy. It is often difficult to identify a corresponding abnormality on neuroimaging to correlate with the clinical examination. High-resolution 3D skull base magnetic resonance imaging (MRI) allows for visualization of the sixth nerve along much of its course and may increase sensitivity for abnormalities in regions that previously were challenging to evaluate. In this review, the authors share their experience with high-resolution imaging of the sixth nerve. For each segment, anatomic features visible on high-resolution imaging are described along with relevant pathologic entities. We present a segmental approach to high-resolution 3D MRI for evaluation of the sixth nerve from the nuclear to the orbital segment.

Migraine and Risk of Ocular Motor Cranial Nerve Palsies: A Nationwide Cohort Study

To determine whether migraine is associated with an increased risk of developing ocular motor cranial nerve palsies (OMCNP). Nationwide retrospective cohort study. Medical records of patients with migraine who were entered in the National Health Insurance Research Database (NHIRD) between 2005 and 2009 were retrieved from the NHIRD in Taiwan. Two cohorts were selected: patients with migraine (n = 138 907) and propensity score-matched controls (n = 138 907). Cohorts were followed until the end of 2010, death, or occurrence of cranial nerve (CN)3, CN4, or CN6 palsies. A Cox proportional hazards regression model was used to calculate the hazard ratios (HRs) and 95% confidence intervals (CIs), which were used to compare to the risk of developing CN3, CN4, and CN6 palsy between cohorts. After a mean follow-up period of 3.1 years (range, 1-6 years), the migraine cohort exhibited a greater risk of developing subsequent CN3, CN4, and CN6 palsies compared with the control cohort (HR, 2.67, P < 0.001; HR, 4.23, P < 0.001; HR, 3.37; P < 0.001). This finding was maintained after excluding potential confounders during sensitivity tests. Moreover, the significant association between migraine and OMCNP remained after we adjusted for potential risk factors of microvascular ischemia. However, different migraine subtypes showed no significant differences. Migraine is an unrecognized risk factor for OMCNP development in adults. Further studies are needed to validate our findings and to delineate the exact pathophysiologic mechanisms linking migraine and OMCNP.

Risk factors and prognosis of isolated ischemic third, fourth, or sixth cranial nerve palsies in the Korean population.

To investigate the risk factors and prognosis for ischemic third, fourth, and sixth cranial nerve palsies in a Korean population. A pair-matched case-control study of 54 Korean patients who were diagnosed with ischemic third, fourth, or sixth cranial nerve palsies was performed to evaluate their risk factors. Using conditional logistic regression analysis, prevalence of potential risk factors in patients and controls, included diabetes mellitus, hypertension, hyperlipidemia, ischemic heart disease, left ventricular hypertrophy (LVH), and smoking were examined retrospectively. A cohort study by Kaplan-Meier method was performed to analyze the recovery period in relation to the number of risk factors or intracranial abnormalities detected by brain computed tomography or magnetic resonance imaging. The mean age of onset was 64.5 years. Of the 54 patients, 16 (29.6%) developed a third nerve palsy, 19 (35.2%) a fourth nerve palsy, and 19 (35.2%) a sixth nerve palsy. The risk factors of diabetes mellitus, hypertension, and hyperlipidemia were significantly more prevalent than other risk factors of heart disease, LVH, and smoking. The mean number of risk factors was 2.3 ± 0.6 in the third nerve palsy group, 1.7 ± 0.9 in the fourth nerve palsy group, and 1.6 ± 1.0 in the sixth nerve palsy group. Patients with 2 or more risk factors showed a longer recovery period (9.0 ± 5.1 weeks) than did patients who had 1 risk factor (6.1 ± 2.2 weeks). Patients with intracranial abnormalities on neuroimaging showed a longer recovery time (10.4 ± 2.7 weeks) than did those without intracranial abnormalities (7.5 ± 4.8 weeks). Ischemic ocular motor cranial nerve palsy is closely related to diabetes mellitus, hypertension, and hyperlipidemia in Korean patients. Compared with the fourth or sixth nerve palsy groups, the third nerve palsy group showed a tendency to have multiple risk factors. Recovery takes longer when 2 or more risk factors were present or when abnormal findings were observed on neuroimaging.