Update on the medial longitudinal fasciculus syndrome.

The medial longitudinal fasciculus is a key structure for conjugate horizontal eye movements by relaying signals from the abducens internuclear neurons to the medial rectus subdivision of the contralateral oculomotor nucleus. Thus, lesions involving the medial longitudinal fasciculus give rise to a typical neuro-ophthalmological sign, the internuclear ophthalmoplegia, which is characterized by impaired adduction of the ipsilesional eye and dissociated abducting nystagmus of the contralateral eye during attempted contralesional horizontal gaze. In addition, medial longitudinal fasciculus lesions may produce various other ocular motor abnormalities since the medial longitudinal fasciculus also conveys the signals for the control of the vestibulo-ocular reflex and smooth pursuit. Other possible ocular motor abnormalities include spontaneous vertical-torsional nystagmus, contraversive ocular tilt reaction, and impaired vestibulo-ocular reflex, especially for the contralesional posterior canal. Recognition of the ocular motor findings observed in the medial longitudinal fasciculus syndrome would aid in detection and localization of potentially grave lesions involving the brainstem.

Comparison of MOG and AQP4 antibody seroprevalence in Korean adults with inflammatory demyelinating CNS diseases.

We aimed to compare seroprevalence of anti-myelin oligodendrocyte glycoprotein (MOG) and anti-aquaporin-4 (AQP4) antibodies in Korean adults with inflammatory demyelinating diseases (IDDs) of the central nervous system (CNS), based on a multicenter nationwide database. Sera were analyzed using a live cell-based assay for MOG and AQP4 antibodies. Of 586 Korean adults with IDDs of the CNS, 36 (6.1%) and 185 (31.6%) tested positive for MOG and AQP4 antibodies, respectively. No participant showed double positivity. Seroprevalence of MOG antibodies was about five times lower than that of AQP4 antibodies in a large cohort of Korean adults with IDDs of the CNS.

Cerebellar infarction presenting with isolated positional vertigo: differentiating factors for benign paroxysmal positional vertigo.

BACKGROUND: Isolated central positional vertigo (CPV) due to cerebellar infarction is often difficult to differentiate from benign paroxysmal positional vertigo (BPPV). Here, we aimed to evaluate whether vascular risk factors and serum vitamin D level can differentiate between positional vertigo types. METHODS: A total of 78 consecutive patients were consecutively enrolled from January 2017. All CPV patients had a National Institutes of Health Stroke Scale score of 0 and cerebellar infarctions confirmed by brain MR imaging. Vascular risk factors and serum 25-hydroxyvitamin D levels were compared between the two groups of patients. RESULTS: The proportion of men was higher in the CPV than in the BPPV group (p = 0.004). Atrial fibrillation was common in the CPV group on univariate analysis (p = 0.046). However, there were no independent differentiating factors between the two groups. The proportion of patients according to the number of risk factors was significantly different between the two groups (linear by linear association test, p = 0.02). The mean serum 25-hydroxyvitamin D level did not differ. Also, the proportions of vitamin D insufficiency and deficiency did not differ significantly between the two groups. CONCLUSIONS: Increased number of vascular risk factors including male sex suggested more CPV than BPPV. However, the serum vitamin D level was below the normal range in both groups. Our results demonstrate that serum vitamin D level has little value in the differential diagnosis of positional vertigo. Efforts to identify differentiating factors are warranted, and accumulating evidences including our research may lead to a diagnostic algorithm for isolated positional vertigo.

Differential diagnosis of acute vascular vertigo.

PURPOSE OF REVIEW: The current review covers recent advances in vascular vertigo in terms of diagnostic strategies, clinical/laboratory features, pathophysiology, and differential diagnosis. RECENT FINDINGS: Acute strokes presenting with isolated dizziness/vertigo without other obvious symptoms or signs of central nervous system involvements may be easily mistaken as peripheral vestibulopathy. For correct diagnosis of vascular vertigo, the importance of clinical history (timing and triggers) and targeted bedside examination cannot be overemphasized. In addition to Head Impulse-Nystagmus-Test of Skew, several differential strategies have been advanced by adopting a combination of clinical history, bedside or laboratory examination, and imaging for diagnosis of vascular vertigo. Circumscribed cerebellar and brainstem lesions may cause isolated central vestibular syndromes with characteristic vestibular and ocular motor manifestations. Recognition of these findings would aid in localizing the lesions and understanding the function of each central vestibular structure. Central positional nystagmus (CPN) may mimic benign paroxysmal positional vertigo (BPPV), but additional oculomotor or neurological findings mostly permit differentiation of CPN from BPPV. SUMMARY: In acute vestibular syndrome, discriminating vascular causes is still challenging especially when other central symptoms and signs are not evident. An integrated approach based on understanding of clinical features, laboratory findings, speculated mechanisms, and limitations of current diagnostic tests will lead to better clinical practice.

Impact of Visceral Adipose Tissue on Clinical Outcomes After Acute Ischemic Stroke.

Background and Purpose- The purpose of this study was to investigate the association between adiposity using adipose tissue imaging and stroke outcomes in acute ischemic stroke patients treated with intravenous thrombolysis. Methods- A total of 127 patients with acute ischemic stroke treated with intravenous thrombolysis who underwent abdominal computed tomography on admission were enrolled in this prospective cohort study. Patients were grouped according to their visceral adipose tissue (VAT) proportion tertile. The primary outcome was measured using the modified Rankin Scale 3 months after symptom onset. Favorable and excellent outcomes were defined as modified Rankin Scale scores of 0 to 2 and 0 to 1, respectively. Results- As VAT proportion tertile increased, the number of patients exhibiting a favorable or excellent outcome decreased. In the final multivariable analysis after adjustments for confounders, patients in the highest VAT proportion tertile showed a decreased probability of a favorable and excellent outcome compared with those in the lowest tertile (odds ratio=0.18; 95% CI, 0.05-0.60; P=0.005 and odds ratio=0.13; 95% CI, 0.02-0.64; P=0.012, respectively). Obese patients (body mass index ≥25) also showed an excellent outcome compared with nonobese patients (odds ratio=4.88; 95% CI, 1.47-7.85; P=0.011). Among obese patients, those with an excellent outcome presented a significantly lower VAT proportion than those without (38.2% versus 46.1%, P=0.006). Conclusions- Results of this study indicate that low visceral abdominal fat proportion is associated with a favorable and excellent outcome in acute ischemic stroke patients treated with intravenous thrombolysis. Better clinical outcomes in obese patients were also associated with a lower proportion of VAT.

HbA1c (Glycated Hemoglobin) Levels and Clinical Outcome Post-Mechanical Thrombectomy in Patients With Large Vessel Occlusion.

Background and Purpose- We analyzed the relationship between HbA1c (glycated hemoglobin) levels and clinical outcomes in patients with large vessel occlusion treated with mechanical thrombectomy (MT). Methods- A total of 534 patients with acute ischemic stroke (AIS) treated with MT were enrolled in this prospective cohort study. The primary outcome measured was the modified Rankin Scale score at 3 months, according to HbA1c level. High HbA1c levels were defined as a plasma level of HbA1c >6.5%. Favorable outcomes were defined as functional independence, with modified Rankin Scale scores of 0 to 2. Secondary functional outcomes included mortality, early clinical outcomes, and intracranial hemorrhage. Results- The number of patients with a favorable outcome was significantly lower in patients with HbA1c >6.5% than in those with HbA1c ≤6.5% (28.8% versus 42.1%; P=0.006). In multivariate analysis, high HbA1c levels (especially >7.0% HbA1c) were significantly associated with poor functional outcomes 3 months after AIS in patients with large vessel occlusion treated with MT. High HbA1c was also significantly associated with increased mortality and worse early clinical outcomes after AIS in patients treated with MT. Subgroup analyses showed that HbA1c >6.5% was associated with significantly lower odds of functional independence at 3 months after AIS, when comparing the recanalized group with nonrecanalized patients. Conclusions- These results suggest that high HbA1c level is an independent predictor of a poor outcome at 3 months after AIS in patients with large vessel occlusion treated with MT, particularly in those with recanalization, and may augment the risk of mortality and early clinical worsening after AIS.

Impact of Microbleeds on Outcome Following Recanalization in Patients With Acute Ischemic Stroke.

Background and Purpose- We analyzed the association between cerebral microbleeds (CMBs) and clinical outcome in acute ischemic stroke patients and especially in a subgroup of patients with successful recanalization. Methods- A total of 1532 acute ischemic stroke patients treated with intravenous thrombolysis or mechanical thrombectomy were enrolled in this prospective cohort study. The primary outcome was measured using the modified Rankin Scale at 3 months, according to the CMB status based on magnetic resonance imaging at admission. Favorable outcome was defined as functional independence with modified Rankin Scale scores of 0 to 2. Secondary outcomes included the occurrence of symptomatic intracranial hemorrhage. Results- There was no statistically significant association between the presence of CMB and favorable outcome at 3 months when considering all patients (44.3% versus 37.6%; P=0.121). In patients with recanalization, the number of patients with favorable outcomes was significantly higher in the CMB-negative than in the CMB-positive group (57.0% versus 36.0%; P<0.001). In the final multivariate analysis, the presence of CMB, and in particular high CMB burden (≥5), and lobar location, were significantly associated with less favorable 3-month outcomes (odds ratio=0.57; 95% CI, 0.33-0.97; P=0.038) and symptomatic intracranial hemorrhage (odds ratio=3.21; 95% CI, 1.37-7.49; P=0.007) in patients with recanalization. In the analysis of subgroups, a statistically significant interaction was found between CMB presence and recanalization in predicting functional outcomes at 3 months. Conclusions- These results indicate that the presence of CMBs, and especially high burden and lobar location, are independent predictors of poor 3-month clinical outcomes and may increase symptomatic intracranial hemorrhage risk in acute ischemic stroke patients with recanalization. Our findings suggest that CMBs lead to more unfavorable effects in patients with recanalization after large vessel occlusion than in those without recanalization.

Integration of sputter-deposited multiferroic CoFe2O4-BiFeO3 nanocomposites on conductive La0.7Sr0.3MnO3 electrodes.

The structure, magnetic and ferroelectric properties of sputtered epitaxial CoFe2O4-BiFeO3 (CFO-BFO) nanocomposite thin films grown on La0.7Sr0.3MnO3 (LSMO) layers on (001) oriented SrTiO3 (STO) substrates and on STO-buffered Si are described. The as-grown LSMO thin films were smooth and poorly conductive but the resistivity was reduced and the surfaces roughened after annealing. Cosputtered CFO and BFO on STO formed vertically aligned nanostructures consisting of epitaxial spinel CFO pillars within a perovskite BFO matrix, but the rough surface of the annealed LSMO film promoted additional CFO pillar orientations. A reorientation of the CFO magnetic easy axis to an in-plane direction occurred as the LSMO became thicker due to changes in the strain state of the CFO pillars. The LSMO underlayer enabled the ferroelectric response of the BFO to be measured. Nanocomposites were grown onto LSMO/SrTiO3/Si which provides a path towards large scale integration of electrically contacted nanocomposites on Si.

Central vertigo.

PURPOSE OF REVIEW: This review considers recent advances in central vertigo in terms of clinical and laboratory features and pathophysiology. RECENT FINDINGS: Strokes presenting dizziness-vertigo are more likely to be associated with a misdiagnosis in the emergency setting. The risk of future strokes after discharge is higher in patients diagnosed with peripheral vertigo than in control patients. Strokes and transient ischemic attacks account for one-quarter of acute transient vestibular syndrome. Diagnosis of acute combined central and peripheral vestibulopathy such as anterior inferior cerebellar artery infarction requires additional consideration whenever applying the HINTS (head impulse test, direction-changing gaze-evoked nystagmus, and test of skew). Heat illness and metronidazole have been recognized as new causes of central vestibulopathy. Some new findings have also been added to the clinical and laboratory features of central vertigo. SUMMARY: Central vertigo is a heterogeneous group of disorders with diverse clinical spectrums. An integrated approach based on understanding of clinical features, laboratory findings, speculated mechanisms, and limitations of current diagnostic tests will lead to better clinical practice.

Ocular Motor Dysfunction Due to Brainstem Disorders.

BACKGROUND: The brainstem contains numerous structures including afferent and efferent fibers that are involved in generation and control of eye movements. EVIDENCE ACQUISITION: These structures give rise to distinct patterns of abnormal eye movements when damaged. Defining these ocular motor abnormalities allows a topographic diagnosis of a lesion within the brainstem. RESULTS: Although diverse patterns of impaired eye movements may be observed in lesions of the brainstem, medullary lesions primarily cause various patterns of nystagmus and impaired vestibular eye movements without obvious ophthalmoplegia. By contrast, pontine ophthalmoplegia is characterized by abnormal eye movements in the horizontal plane, while midbrain lesions typically show vertical ophthalmoplegia in addition to pupillary and eyelid abnormalities. CONCLUSIONS: Recognition of the patterns and characteristics of abnormal eye movements observed in brainstem lesions is important in understanding the roles of each neural structure and circuit in ocular motor control as well as in localizing the offending lesion.

The effectiveness of using magnetic resonance imaging in syncope patients visiting an emergency department: A case-control study.

OBJECTIVE: To evaluate the effectiveness of brain magnetic resonance imaging in excluding neurological causes in patients with syncope. METHODS: This retrospective, observational, cohort study was conducted at the Chonnam National University Hospital, Gwangju, South Korea, and comprised medical record of patients with syncope from January 2011 to February 2016. The ratio of abnormal findings, the characteristics of the patients who showed abnormal findings and the relationships between the presence of neurological problem and other clinical factors were analysed. SPSS 18 was used for statistical analysis. RESULTS: Of the 1,045 patients, 142(13.5%) underwent additional magnetic resonance imaging. The results showed that 15(10.6%) patients had abnormal findings indicating neurological problems; of them, 9(60%) showed vascular stenosis, 4(27%) showed cerebral infarction, and 2(13%) showed brain tumours. The neurological problems shown were significantly higher for older patients (p=0.006) and those with the underlying diseases of hypertension (p=0.014) and coronary artery disease (p=0.008). Of these patients in particular, age (p=0.036) and history of coronary artery disease (p=0.029) were significantly associated with abnormal findings in their magnetic resonance imaging. CONCLUSIONS: Although there are no specific neurological examinations or computed tomography findings currently used in patients with syncope in the emergency department, magnetic resonance imaging may be performed to exclude neurological causes in older patients as well as those with a history of coronary artery disease.

MRI measurements of brainstem structures in patients with vascular parkinsonism, progressive supranuclear palsy, and Parkinson's disease.

Magnetic resonance (MR) measurements of brainstem structures have been reported to be useful in differentiating patients with progressive supranuclear palsy (PSP) from those with Parkinson's disease (PD). The aim of this study was to determine whether quantitative measurements of brainstem structures on MR images can help differentiate vascular parkinsonism (VaP) from degenerative parkinsonism (PD and PSP). Areas of the midbrain and pons, and widths of the superior cerebellar peduncle (SCP) and middle cerebellar peduncle (MCP) were measured in 62 patients with PD, 25 patients with PSP (11 probable and 14 possible), and 24 patients with VaP on T 1-weighted MR images. The midbrain-to-pons area ratio (M/P ratio), MCP-to-SCP width ratio (MCP/SCP ratio), and MR parkinsonism index (MRPI; P/M × MCP/SCP) were calculated. The midbrain area and M/P ratio of patients with VaP (104 and 0.22 mm2, respectively) were smaller than those in patients with PD (121 and 0.24 mm2, respectively) and larger than those in patients with PSP (90 and 0.19 mm2, respectively). The MRPI was significantly larger in patients with PSP (13.6) in comparison with those with PD (10.1) and VaP (10.7). However, the MRPI of patients with VaP was not significantly different from patients with PD. Our study showed that MRPI was useful in differentiating PSP from VaP or PD. Thus, MR imaging measurements of brainstem structures may help differentiate patients with VaP from those with PD and PSP.

The Association of Musculoskeletal Pain with Bone Mineral Density in Patients with Parkinson's Disease.

BACKGROUND: Pain and osteoporosis are common in Parkinson's disease (PD), and lower bone mineral density (BMD) or osteoporosis may be associated with an increased risk of reporting to have pain in the general population. The aim of this study was to determine whether there is an association between the pain subtypes and the BMD in patients with PD. METHODS: We included 162 PD patients. Pain was assessed using the patients' descriptions, a structured interview, a detailed neurologic examination, and the Visual Analogue Scale. BMD was measured using dual energy X-ray absorptiometry scans. RESULTS: Of the 162 PD patients, 120 had chronic pain, while 42 reported no pain. The most prevalent type of pain was musculoskeletal, followed by radicular/neuropathic, dystonic, and central. PD patients with musculoskeletal pain had a lower BMD than PD patients without pain. Multivariate regression analysis showed that the low BMD of the lumbar spine, hip, and femoral neck were related to old age, female gender, low MBI, and the presence of musculoskeletal pain. CONCLUSION: PD patients with musculoskeletal pain have low BMD and are at risk for developing osteoporosis. If a PD patient has musculoskeletal pain and other risk factors related to low BMD, clinicians should consider screening for osteoporosis.

The Validity and Reliability of the Korean Version of the Stigma Scale for Chronic Illness 8-Items (SSCI-8) in Patients with Neurological Disorders.

PURPOSE: The aim of this study was to develop a Korean version of the Stigma Scale for Chronic Illness 8-items (SSCI-8) and then assess its reliability and construct validity among patients with neurological conditions. METHOD: Patients diagnosed with stroke, Parkinson's disease, epilepsy, multiple sclerosis, myasthenia gravis, and amyotrophic lateral sclerosis were recruited. Reliability was assessed for internal consistency with Cronbach's alpha coefficient. Exploratory factor analysis (EFA) was used to extract potential factors of Korean SSCI-8. Convergent validity was assessed by correlating scores on the Korean SSCI-8 with scores for depression using the Beck Depression Inventory, anxiety using Spielberger's State-Trait Anxiety Inventory, and functional ability using the Korean modified Barthel Index (K-MBI), respectively. RESULTS: Of the total 202 patients enrolled in this study, 119 (58.9 %) were recruited with stroke, 33 (16.3 %) with Parkinson's disease, and 29 (14.4 %) with epilepsy. The Korean SSCI-8 had a high internal consistency (Cronbach's alpha = 0.90). The Korean SSCI-8 retrieved one factor from eight items by the EFA, and all factor loading scores were above 0.70 (0.71-0.84). The Korean SSCI-8 was correlated positively with depression (r = 0.74, p < 0.001) and anxiety (r = 0.61, p < 0.001), and negatively with the K-MBI (r = -0.48, p < 0.001). CONCLUSION: This study shows that the Korean SSCI-8 is a unidimensional model, even though it includes items of both enacted and internalized stigma. It is both reliable and valid for assessing stigma among Korean patients with neurological disease.

Central Trochlear Palsy: Report of Two Patients With Ipsilesional Palsy and Review of the Literature.

BACKGROUND: The trochlear (fourth) nerve is the only cranial nerve that decussates before emerging from the posterior aspect of the brainstem. Lesions involving the trochlear nucleus or fascicles mostly give rise to contralesional superior oblique palsy (SOP). METHODS: We report 2 patients with SOP on the side of intraaxial lesions with a literature review on central trochlear palsy. RESULTS: The lesions are more commonly located posterior to the cerebral aqueduct in patients with ipsilesional SOP than in those with contralesional SOP. CONCLUSIONS: Intraaxial lesions may cause ipsilesional or contralesional SOP depending on the lesion location along the course of trochlear fascicle in the brainstem.

Clinical Implications of Changes in Individual Platelet Reactivity to Aspirin Over Time in Acute Ischemic Stroke.

BACKGROUND AND PURPOSE: Time-dependent changes in individual platelet reactivity have been detected in patients with coronary artery disease. Therefore, we sought to evaluate the time-dependent changes in platelet reactivity to aspirin during the acute stage after ischemic stroke and the clinical implications of variable patient responses to aspirin in acute ischemic stroke. METHODS: We conducted a single-center, prospective, observational study. The acute aspirin reaction unit (ARU) was measured after 3 hours of aspirin loading, with higher values indicating increased platelet reactivity despite aspirin therapy. The follow-up ARU was measured on the fifth day of consecutive aspirin intake. The numeric difference between the follow-up ARU and the acute ARU was defined as ΔARU and was stratified into quartiles. Early neurological deterioration was regarded as an early clinical outcome. RESULTS: Both the acute ARU (476±69 IU) and the follow-up ARU (451±68 IU) were measured in 349 patients in this study. Early neurological deterioration was observed in 72 patients (20.6%). Changes in aspirin platelet reactivity over time showed an approximately Gaussian distribution. The highest ΔARU quartile was independently associated with early neurological deterioration (odds ratio, 3.19; 95% confidence interval, 1.43-7.10; P=0.005) by multivariate logistic regression analysis. CONCLUSIONS: The results of our study showed that the increase in platelet reactivity to aspirin over time is independently associated with early neurological deterioration in patients with acute ischemic stroke. In addition, during the acute stage of ischemic stroke, serial platelet reactivity assays may be more useful than a single assay for identifying the clinical implications of aspirin platelet reactivity after ischemic stroke.

Isolated unilateral infarction of the cerebellar tonsil: ocular motor findings.

The oculomotor abnormalities with isolated infarction of the cerebellar tonsil are unknown. In a patient with acute infarction of the right tonsil, we found (1) nearly completely abolished ipsilateral smooth pursuit and impaired contralateral pursuit, (2) a low-amplitude ipsilesional right-beating nystagmus without fixation, (3) gaze-holding deficits, and (4) normal vestibulo-ocular reflex. These findings contrast with striking vestibular abnormalities reported with unilateral flocculus and anterior tonsil infarction. Taken together, these findings allow more diagnostic certainty in cerebellar patients, help resolve controversies about interpretation of experimental findings in monkeys, and clarify homologies between the monkey and human cerebellum.

Comparison of the Brain Volume in Essential Tremor and Parkinson's Disease Tremor Using an Automated Segmentation Method.

BACKGROUND: Essential tremor (ET) and Parkinson's disease (PD) are common neurological disorders in elderly people, and some features of ET and PD may overlap. Quantitative analysis of brain atrophy may be useful in differentiating neurodegenerative disorders. The aim of this study was to identify the volumetric differences of subcortical structures in patients with ET and PD tremor using an automated segmentation method. METHODS: Volumetric MRIs were obtained in 45 patients with ET, 45 patients with PD tremor, and 45 age- and sex-matched control subjects. The volume of the different brain structures was measured by the automated segmentation method (FreeSurfer). RESULTS: Volumetric data obtained with automated segmentation of cerebral regions showed a significant atrophy of the cerebellum in patients with ET. Cerebellar atrophy of ET patients was more significant in the white matter than in the grey matter, and it was noted only in patients with ET having a head tremor. No volumetric differences were found between the PD group and the control group. CONCLUSION: Our study suggests that volumetric differences in subcortical structures using whole brain segmentation method may help to differentiate ET from PD tremor.