Topographic Consideration on the Occurrence of Ipsilesional Facial Paresis in Lateral Medullary Infarction.

INTRODUCTION: The purpose of this study was to identify course of the corticobulbar tract and factors associated with the occurrence of facial paresis (FP) in lateral medullary infarction (LMI). METHODS: Patients diagnosed with LMI who were admitted to tertiary hospital were retrospectively investigated and divided into two groups based on the presence of FP. FP was defined as grade 2 or more by the House-Brackmann scale. Differences between the two groups were analyzed with respect to anatomical location of the lesions, demographic data (age, sex), risk factors (diabetes, hypertension, smoking, prior stroke, atrial fibrillation, and other cardiac risk factors for stroke), large vessel involvement on magnetic resonance angiography, other symptoms and signs (sensory symptoms, gait ataxia, limb ataxia, dizziness, Horner syndrome, hoarseness, dysphagia, dysarthria, nystagmus, nausea/vomiting, headache, neck pain, diplopia, and hiccup). RESULTS: Among 44 LMI patients, 15 patients (34%) had FP, and all of them had ipsilesional central-type FP. The FP group tended to involve upper (p < 0.0001) and relative ventral (p = 0.019) part of the lateral medulla. Horizontally large lesion was also related to the presence of FP (p = 0.044). Dysphagia (p = 0.001), dysarthria (p = 0.003), and hiccups (p = 0.034) were more likely to be accompanied by FP. Otherwise, there were no significant differences. CONCLUSION: The results of present study indicate that the corticobulbar fibers innervating the lower face decussate at the upper level of the medulla and ascend through the dorsolateral medulla, where the concentration of the fibers is densest near the nucleus ambiguus.

Temporal Characteristics of Penetration and Aspiration in Patients with Severe Dysphagia Associated with Lateral Medullary Syndrome.

To assess the severity and timing of penetration and aspiration (PA) of severe dysphagia after lateral medullary syndrome (LMS) and its association with temporal characteristics. We performed videofluoroscopic swallowing studies (VFSS) in 48 patients with LMS and severe dysphagia and 26 sex- and age-matched healthy subjects. The following temporal measures were compared between groups: velopharyngeal closure duration (VCD); hyoid bone movement duration (HMD); laryngeal vestibular closure duration (LCD); upper esophageal sphincter (UES) opening duration (UOD); stage transition duration (STD) and the interval between laryngeal vestibular closure and UES opening (LC-UESop). The association between temporal measures and Penetration-Aspiration Scale (PAS) scores was analyzed. Differences in timing measures were compared between subgroups (safe swallows, and swallows with PA events during and after the swallow). PAS scores ≥ 3 were seen in 48% of swallows (4% occuring before, 35% occurred during and 61% after the swallow) from the LMS patients. Significantly longer STD and LC-UESop were found in the patients compared to the healthy subjects (p < 0.05). Significant negative correlations with PA severity were found for HMD, LCD, and UOD. Short UOD was the strongest predictor with an area under the receiver-operating-characteristic curve of 0.66. UOD was also significantly shorter in cases of PA after the swallow (p < 0.01). Patients with LMS involving severe dysphagia exhibit a high frequency of PA (mostly during and after swallowing). PA events were associated with shorter UOD, HMD, and LCD. Notably, shortened UOD appears to be strongly associated with PA.

Outcome of Surgery to Improve Swallowing in Patients with Lateral Medullary Syndrome: A Retrospective Cohort Study.

The study investigated surgical interventions to improve dysphagia in patients with lateral medullary syndrome (LMS), along with optimal scheduling of surgery and prognostic factors. In this retrospective, single-center cohort study, dysphagia patients with LMS who underwent surgery between January 2010 and December 2021 were enrolled. The National Outcomes Measurement System (NOMS) was used to classify swallowing function (level 1: only tube feeding, level 5: without tube feeding). Patients were divided into four groups. Groups 1 and 2, LMS onset within 1 year, and groups 3 and 4, onset after 1 year. Groups 1 and 3 had infarctions confined to the oblongata. Groups 2 and 4 had infarctions extending to the cerebellum. The primary outcome was the time to achieve NOMS ≥ 5. The final NOMS level and pathological findings were considered. Nineteen cases were included. Group 4 comprised one case and was excluded. The mean overall preoperative NOMS was 1.11. The mean time to NOMS ≥ 5 was 9.6 months (95% confidence interval: 5.04-14.2), and that to NOMS ≥ 5 was 1.67 (1.07-2.26), 11.4 (4.71-18.1), and 7.6 (5.15-10.1) months for groups 1, 2, and 3, respectively. Group 1 achieved NOMS ≥ 5 earlier than groups 2 and 3 (P = 0.01 and 0.03, respectively). The overall final NOMS value was 4.68. Fourteen patients had atrophy or fibrosis of the cricopharyngeal muscle. In conclusion, surgery was effective for effective for treating dysphagia in LMS patients. However, improvement is prolonged if > 1 year has passed since onset or the infarction extended to the cerebellum.

Midlateral medullary infarction presenting with isolated thermoanaesthesia: a case report.

BACKGROUND: A small lateral medullary lesion could produce isolated impairment of temperature sensation without concomitant impaired pain sensation. However, only one such case has ever been reported, and there are no reports on subjective symptoms and detailed somatosensory testing. CASE PRESENTATION: Herein, we report the case of a 53-year-old female patient presenting with impaired temperature sensation on the left half of her body, from the neck down, following a small infarction of the right midlateral medulla. The chronological changes in the patient's introspection regarding impairment of thermoception and the results of detailed somatosensory tests, including thermal sense, are shown in this report. CONCLUSIONS: Thorough somatosensory tests, personal descriptions of symptoms, and electrophysiological quantification of similar cases are needed to improve our understanding of the neurological separation of the sensations of pain and temperature at the medullary level.

Sinus arrest following acute lateral medullary infarction.

Lateral medullary syndrome (LMS) is an ischemic stroke of the medulla oblongata that involves the territory of the posterior inferior cerebellar artery. LMS is often missed as the cause of autonomic dysregulation in patients with recent brain stem stroke. Due to the location of the nucleus tractus solitarius (NTS), the dorsal vagal nucleus, and the nucleus ambiguous in the lateral medulla oblongata, patients with LMS occasionally have autonomic dysregulation-associated clinical manifestations. We report a case of LMS-associated autonomic dysregulation. The case presented by recurrent syncope, requiring permanent pacemaker placement. This case shows the importance of recognizing LMS as a potential cause of life-threatening arrhythmias, heart block, and symptomatic bradycardia. Extended cardiac monitoring should be considered for patients with medullary strokes.

Challenging the diagnosis of a posterior circulation dissecting aneurysm.

INTRODUCTION: I ntracranial vertebral dissections have polymorphs clinical presentations and can lead to haemorrhagic complications if they are intracranial. We here describe a case of a thrombosed dissecting aneurysm of postero-inferior cerebellar artery (PICA) revealed by a Wallenberg syndrome preceded by headaches. CASE: A 23-year-old patient, without neurological or vascular past medical history, was admitted for dizziness preceded by headache. The clinical examination on admission revealed an incomplete Wallenberg syndrome, associating hemiface sensitive deficit, Horner's syndrome, dysmetria and nystagmus. The brain MRI showed a latero-medullary infarct with a homolateral PICA thrombosed dissecting aneurysm. CONCLUSION: The diagnosis of intracranial dissecting aneurysms needs particular caution because aneurysm sac thrombosis can give false reassurance on angiographic MR sequences. Moreover, the anatomic features of intracranial artery walls make them prone to sub-adventitial dissection and subsequent subarachnoid haemorrhages. Therefore, antithrombotic therapy should be used with caution, due to the risk of bleeding in these intracranial dissections.

Pediatric Medullary Stroke, Severe Dysphagia, and Multimodal Intervention.

Lateral medullary syndrome/Wallenberg syndrome is a stroke in the lateral medulla with symptoms often including dysphagia and dysphonia. In adults, this stroke is the most common brainstem stroke, but it is rare in the pediatric population. Insults to the medulla can involve the "swallowing centers," the nucleus ambiguus and nucleus tractus solitarius, and the cranial nerves involved in swallowing, namely IX (glossopharyngeal) and X (vagus). These individuals can develop severe dysphagia with an inability to trigger a swallow due to pharyngeal weakness and impaired mechanical opening of the upper esophageal sphincter (UES) which can result in aspiration. We present a 7-year-old male with 22q11.2 deletion syndrome (velocardiofacial syndrome) and velopharyngeal insufficiency who underwent pharyngeal flap surgery at an outside hospital whose post-operative course was complicated by adenovirus, viral myocarditis, and dorsal medullary stroke. He required a tracheostomy and gastrostomy tube. He was discharged from that hospital and readmitted to our hospital 4 months later for increased oxygen requirement, requiring a 5 month admission in the intensive care units. His initial VFSS revealed absent UES opening with the entire bolus remaining in the pyriform sinuses resulting in aspiration. His workup over the course of his admission included multiple videofluoroscopic swallow studies (VFSS), flexible endoscopic evaluation of swallowing (FEES), and pharyngeal and esophageal manometry. Intervention included intensive speech therapy, cricopharyngeal Botox® injection, and cricopharyngeal myotomy. Nineteen months after his stroke, he transitioned to oral intake of solids and liquids with adequate movement of the bolus through the pharynx and UES and no aspiration on his VFSS.

A case of vertebral artery compression syndrome mimicking primary lateral sclerosis.

PURPOSE: Vertebral artery compression syndrome (VACS) is an under-recognised condition that may be misdiagnosed as motor neuron disease. We report a case presenting features initially suggestive of primary lateral sclerosis (PLS) but later found to be VACS. CASE PRESENTATION: A 65-year-old man with hypertension was referred to our neurology department in the suspect of PLS. He presented with a 10-year history of involuntary jerk of the left lower limb, which ascended to the left upper limb 9 years later. He also developed intermittent painful spasms with a tendency to drag his left leg. His symptoms fluctuated with blood pressure. Neurological examination revealed upper motor neuron signs without lower motor neuron or sensory involvement. Electrophysiology studies were unremarkable. Brain MRI disclosed the left side of medulla oblongata was compressed by the tortuous left vertebral artery. Diffusion tensor tractography confirmed the corresponding corticospinal tract disruption. He was diagnosed with VACS and treated with antispasmodic medications and antihypertensive drugs. CONCLUSIONS: VACS should be considered into the differential diagnoses of PLS. A thorough clinical assessment and careful interpretation of brain MRI with advanced diffusion neuroimages can help confirm the diagnosis.

Association of Vertebral Artery Hypoplasia and Vertebrobasilar Cerebrovascular Accident.

Background and Objectives: Vertebral artery hypoplasia (VAH) is a controversial risk factor for cerebral infarction. The aim of this study was to analyze the prevalence of vertebral artery hypoplasia and to evaluate its association with vertebrobasilar cerebrovascular accidents. Materials and Methods: The study was conducted in the Neurology Departments of the Republican Vilnius University Hospital from 2015 to 2020. Data of 742 subjects (133 patients with posterior circulation infarction or vertebral artery syndrome (PCI/VAS), 80 patients with anterior circulation infarction (ACI) and 529 control subjects with no symptoms of cerebrovascular accident) were analyzed. Ultrasound examination of the extracranial internal carotid and vertebral arteries (VA) was performed, risk factors were recorded. Results: The mean age of the subjects was 64.51 ± 13.02 years. In subjects with PCI/VAS the diameter of VA was smaller, and the prevalence of VAH was higher compared to those in subjects with ACI and in the control group. A higher degree of VAH in subjects younger than 65 years of age increased the risk of PCI/VAS. Subjects with non-dominant VA diameter of 2.7-2.9 mm had 2.21 times higher risk of PCI/VAS, subjects with non-dominant VA diameter of 2.5-2.6 mm had 2.36 times higher risk of PCI/VAS, and subjects with non-dominant VA diameter of 2.2-2.4 mm had 4.12 times higher risk of PCI/VAS compared with subjects with non-dominant VA diameter of ≥3 mm. Among patients with PCI/VAS those with VAH had lower rates of ischemic heart disease compared with patients with normal VA diameter. There was no difference in the rates of other risk factors between PCI/VAS patients with and without VAH. Conclusions: Vertebral artery hypoplasia is not a rare finding in individuals without symptoms of cerebrovascular accident, but more frequent in patients with vertebrobasilar cerebral infarction or vertebrobasilar artery syndrome. Vertebral artery hypoplasia can be considered a risk factor for posterior circulation infarction in subjects under 65 years of age.

Dysphagia in Lateral Medullary Syndrome: A Narrative Review.

Dysphagia is a common clinical feature of lateral medullary syndrome (LMS) and is clinically relevant because it is related to aspiration pneumonia, malnutrition, increased mortality, and prolonged hospital stay. Herein, the pathophysiology, prognosis, and treatment of dysphagia in LMS are reviewed. The pathophysiology, prognosis, and treatment of dysphagia in LMS are closely interconnected. Although the pathophysiology of dysphagia in LMS has not been fully elucidated, previous studies have suggested that the medullary central pattern generators coordinate the pharyngeal phases of swallowing. Investigation of the extensive neural connections of the medulla oblongata is important in understanding the pathophysiologic mechanism of dysphagia in LMS. Previous studies have reported that most patients with dysphagia in LMS have a relatively good prognosis. However, some patients require tube feeding for several months, even years, due to severe dysphagia, and little has been reported about conditions associated with a poor prognosis of dysphagia in LMS. Concerning specific therapeutic modalities for dysphagia in LMS, in addition to general modalities used for dysphagia treatment in stroke patients, non-invasive modalities, including repetitive transcranial magnetic stimulation and transcranial direct current stimulation, as well as invasive modalities, such as botulinum toxin injection, balloon catheter dilatation, and myotomy for relaxation of the cricopharyngeal muscle, have been applied. For the appropriate application of therapeutic modalities, clinicians should be aware of the recovery mechanisms and prognosis of dysphagia in LMS. Further studies on this topic, as well as studies involving large numbers of subjects on specific therapeutic modalities, should be encouraged.

Characteristics and Prognostic Factors of Swallowing Dysfunction in Patients with Lateral Medullary Infarction.

OBJECTIVES: Lateral medullary infarction mainly impairs the pharyngeal phase of swallowing. We aimed to investigate the utility of the assessment tools of swallowing function in patients with lateral medullary infarction and to determine the factors that could predict the outcomes of swallowing function. MATERIALS AND METHODS: 15 patients with lateral medullary infarction who were admitted to Suiseikai Kajikawa Hospital between August 1, 2016, and March 31, 2020 (age 62.7 ± 14.8 years, 5 women) were enrolled in this prospective study. The diagnosis was made using brain magnetic resonance imaging. We analyzed the factors associated with severe swallowing dysfunction, which was defined as the necessity for tube feeding on the 90th day from admission, with multiple logistic regression analysis. RESULTS: Multivariate analyses identified the repetitive saliva swallowing test, modified water swallowing test, and vertical spread of stroke lesions as independent significant factors affecting severe swallowing dysfunction (p = 0.002, 0.016, and 0.011, respectively). The sub-scores of the pharyngeal phase of the Mann Assessment of Swallowing Ability were also significantly associated with severe swallowing dysfunction (p < 0.001). However, tongue pressure, severe passage pattern abnormality on videofluoroscopic examination, and vertebral artery dissection were not significantly associated with swallowing dysfunction. CONCLUSIONS: Since lateral medullary infarction presents with swallowing dysfunction mainly in the pharyngeal phase, tools that can be used to evaluate the pharyngeal phase of swallowing, such as repetitive saliva swallowing test and modified water swallowing test, are moreuseful than tongue pressure measurement.

Severe Unilateral Proprioceptive Loss in Medullary- Rostral Spinal Cord Infarction. A Posterior Spinal Artery Syndrome.

We draw attention to a unique presentation, severe unilateral loss of limb proprioception, in patients with medullary and rostral spinal cord infarction. Two patients developed acute severe proprioceptive loss in the limbs ipsilateral to infarcts that involved the caudal medulla and rostral spinal cord. They also had symptoms and signs often found in lateral medullary infarction. The proprioceptive loss is attributable to injury to the gracile and cuneate nuclei and/or their projections to the medial lemniscus. The infarct territory is supplied by the posterior spinal branches of the vertebral artery near its penetration into the posterior fossa. The presence of severe ipsilateral proprioceptive loss in a patient with features of lateral medullary infarction indicates involvement of the rostral spinal cord.

Clinical and Radiological Characteristics Associated with Respiratory Failure in Unilateral Lateral Medullary Infarction.

BACKGROUND: The prognosis for unilateral lateral medullary infarction (ULMI) is generally good but may be aggravated by respiratory failure with fatal outcome. Respiratory failure has been reported in patients with severe bulbar dysfunction and large rostral medullary lesions, but its associated factors have not been systematically studied. We aimed to assess clinical and radiological characteristics associated with respiratory failure in patients with pure acute ULMI. MATERIALS AND METHODS: Seventy-one patients (median age 55 years, 59 males) with MRI-confirmed acute pure ULMI were studied retrospectively. Clinical characteristics were assessed and bulbar symptoms were scored using a scale developed for this study. MRI lesions were classified into 4 groups based on their vertical extent (localized/extensive) and the involvement of the open and/or closed medulla. Clinical characteristics, bulbar scores and MRI lesion characteristics were compared between patients with and without respiratory failure. RESULTS: Respiratory failure occurred in 8(11%) patients. All patients with respiratory failure were male (p = 0.336), had extensive lesions involving the open medulla (p = 0.061), progression of bulbar symptoms (p=0.002) and aspiration pneumonia (p < 0.001). Peak bulbar score (OR, 7.9 [95% CI, 2.3-160.0]; p < 0.001) and older age (OR, 1.2 [95%CI, 1.0-1.6]; p=0.006) were independently associated with respiratory failure. CONCLUSIONS: Extensive damage involving the open/rostral medulla, clinically presenting with severe bulbar dysfunction, in conjunction with factors such as aspiration pneumonia and older age appears to be crucial for the development of respiratory failure in pure ULMI. Further prospective studies are needed to identify other potential risk factors, pathophysiology, and effective preventive measures for respiratory failure in these patients.

Vestibular migraine with Wallenberg syndrome: a case report.

BACKGROUND: Vestibular migraine, a kind of acute vestibular syndrome, leads to both migraines and vertigo symptoms in a single patient. The occurrence of vestibular migraine has shown an obvious increase in female groups based on age. Though it is recognized that migraines may cause ischemic lesions in some brain regions, the relationship between vestibular migraine and cerebral infarction has seldom been reported, especially with no known research reports about vestibular migraine with Wallenberg syndrome. Based on this, the connection of the two diseases needs to be the focus of more research. CASE PRESENTATION: The patient, a 35-year-old lady, came to our department with severe vertigo and headaches for approximately two years. She suffered from migraines which attacked about twice yearly for nearly a decade. The diffusive weighted imaging showed a subacute infarction in the right lateral medullar. The clinical characteristics and MRI findings supported the diagnosis of vestibular migraine with Wallenberg syndrome. Along with the normal routine medication for vestibular migraine with Wallenberg syndrome, we also prescribed migraine therapy at the same time. In a 3-month follow-up, the patient had suffered only one vertigo attack and she reported that the migraines were less common and less intense than she was previously experiencing. CONCLUSIONS: Due to the fact that vestibular migraine is one of the risk factors of cerebral ischemia, we need to pay more attention to this phenomenon. The current case suggests that both routine medication on ischemic stroke as well as treatment for migraines should be used concurrently in vestibular migraine with Wallenberg syndrome.

Prospective study of sleep-disordered breathing in 28 patients with acute unilateral lateral medullary infarction.

OBJECTIVE: Acute unilateral lateral medullary infarction (ULMI) is complicated by respiratory failure in 2-6% of patients. However, studies investigating milder respiratory disorders not leading to overt respiratory failure, i.e., sleep-disordered breathing (SDB) and its outcome, are lacking. The aim of our study was to identify and prospectively follow SDB in acute ULMI. METHODS: We prospectively followed 28 patients with MRI-confirmed acute ULMI. Polysomnography (PSG) was performed 1-3 times in the acute phase (at 1-4, 5-10, and 14-21 days after onset of symptoms) and after 3-6 months. PSG recordings in the acute phase were analyzed and compared to the follow-up. RESULTS: Apnea-hypopnea index (AHI) ≥ 5/h, AHI ≥ 15/h, and AHI ≥ 30/h in the acute phase were observed in 22 (79%), 19 (68%), and 10 (36%) patients, respectively. CSA, OSA, mixed CSA/OSA, or multiple interchanging SDB types were observed in the acute phase in 12 (43%), 2 (7%), 2 (7%), and 6 (21%) patients, respectively. Peak AHI varied in individual patients (median at 7 (3-14) days after onset). At follow-up, AHI and central AHI tended to decrease (p = 0.007, p = 0.003, respectively), obstructive AHI did not change (p = 0.396). Sleep architecture partially improved with significantly higher percentage of N2 and lower percentage of wakefulness after sleep onset (p = 0.007, p = 0.012, respectively). CONCLUSIONS: Our data show that SDB, particularly CSA, is common in the acute phase of ULMI and that the frequency of central events decreases in the subacute phase. Further studies are needed to clarify the clinical significance and possible treatment options of SDB in these patients.

The Trouble with Swallowing: Dysphagia as the Presenting Symptom in Lateral Medullary Syndrome.

BACKGROUND: Posterior circulation strokes account for approximately one-fourth of all ischemic strokes, but are frequently misdiagnosed by emergency providers. Current standard stroke screening tools such as the National Institutes of Health Stroke Scale and the Cincinnati Prehospital Stroke Scale are weighted toward anterior circulation stroke diagnosis. Lateral medullary syndrome, a type of posterior circulation stroke, can be particularly challenging to diagnose due to nonspecific presenting symptoms, such as dysphagia. CASE REPORT: This report describes a 65-year-old man who presented with dysphagia, dizziness, and hoarseness. An initial neurological examination did not reveal any gross deficits, and imaging to evaluate for posterior circulation stroke was not obtained. The patient presented the following day with worsening symptoms, prompting imaging that revealed a large cerebellar ischemic infarction. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Although dysphagia frequently occurs in lateral medullary syndrome, it is rarely the presenting symptom in the emergency department. In patients with cerebrovascular risk factors who present with dysphagia, a complete neurological examination should be performed and noncontrast computed tomography (CT) of the head should be obtained if a neurological deficit is appreciated. Due to their poor sensitivity, CT scans can frequently miss posterior circulation strokes, therefore magnetic resonance imaging should be considered if provider suspicion remains high. Emergency providers are encouraged to have a high level of suspicion for this rare but debilitating stroke syndrome to avoid misdiagnosis and delayed care.

Opalski Syndrome Treated with Intravenous Recombinant Tissue Type Plasminogen Activator-Case Report and Review of Literature.

A 65-year-old man with a history of Wallenberg syndrome caused by vertebral artery dissection at 62 years old was admitted to our hospital with nausea, vertigo, right facial dysesthesia, right hemiplegia, crossed sensory disturbance (sensory loss and numbness in the right face and left body below the neck), and right limb ataxia. Magnetic resonance imaging (MRI) performed 80 minutes after onset revealed no acute ischemic stroke lesions, but magnetic resonance angiography (MRA) demonstrated complete occlusion of the right vertebral artery. Based on these neurological and MRA findings, atypical lateral medullary infarction was suggested, and intravenous tissue plasminogen activator (IV-tPA) was started 178 minutes after onset. Right hemiplegia improved immediately after IV-tPA administration. MRI performed on hospital day 2 showed an acute ischemic lesion on the right side of the medulla oblongata, resulting in a diagnosis of Opalski syndrome. Opalski syndrome is a rare subtype of Wallenberg syndrome accompanied by hemiplegia of the side ipsilateral to the lesion, and expansion of the stroke lesion to the corticospinal tract below the pyramidal decussation is considered to cause ipsilateral hemiplegia. Based on this case and previous reports, Opalski syndrome should be considered when limb ataxia and crossed sensory deficit are observed among patients with hyperacute-onset hemiplegia, and IV t-PA therapy should be considered even in the absence of neurological findings such as dysphagia, dysarthria, and Horner's signs and radiological evidence of acute ischemic stroke.

Lateral Medullary Syndrome Following Injury of Lateral Vestibulospinal Tract: Diffusion Tensor Imaging Study.

BACKGROUND: Unilateral lesions of vestibular nucleus can cause lateral medullary syndrome. Little is known about injury of medial and lateral vestibulospinal tract (VST) after dorsolateral medullary infarct. We investigated injury of the lateral VST in patients with typical central vestibular disorder using diffusion tensor tractography (DTT). METHODS: Seven patients with lateral medullary syndrome and ten control subjects were recruited. For the medial VST, we determined seed region of interest (ROI) as medial vestibular nuclei of pons and target ROI on posteromedial medulla. For the lateral VST, the seed ROI was placed on lateral vestibular nuclei of pons, and the target ROI on posterolateral medulla. Fractional anisotropy (FA), mean diffusivity (MD), and tract volume were measured. RESULT: Reconstructed lateral VST on both sides had significantly lower FA values in patients than controls (p<0.05). Tract volume of lateral VST in affected side was significantly lower than unaffected side and control group (p<0.05). However, no DTI parameters of the medial VST differed between patients and controls (p>0.05). CONCLUSION: Injury of the lateral VST was demonstrated in patients with lateral vestibular syndrome following dorsolateral medullary infarct. Analysis of the lateral VST using DTT would be helpful in evaluation of patients with lateral medullary syndrome.

A Case of Wallenberg's Syndrome Presenting with Spontaneous Thrombosis of a Vertebral Artery Aneurysm.

Complete spontaneous thrombosis of intracranial aneurysms is uncommon. Although this type of thrombosis is largely asymptomatic, in rare cases it can be accompanied by parent artery occlusion and ischemic stroke. There are limited reports of complete thrombosis of an unruptured aneurysm of the internal carotid artery and middle cerebral artery. Furthermore, there are no reports of occlusion of the vertebral artery caused by thrombosis of an aneurysm. The mechanisms of spontaneous thrombosis are not established. However, aneurysm morphology, arteriosclerosis, and stagnation of aneurysm flow have been suggested. Herein, we present a novel case of Wallenberg's syndrome caused by a fusiform aneurysm in which complete thrombosis of the proximal vertebral artery occurred. We discuss the mechanisms of thrombosis caused by an unruptured aneurysm, which may be useful for managing such patients who present with transient ischemic attacks.