Lateral Medullary Infarction Patients Research Articles

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.

Abstract WMP83: Arterial Dissection: A Still Underestimated Cause Of Lateral Medullary Infarction

Introduction: Although the association between vertebral artery or posterior inferior cerebellar artery dissection and lateral medullary infarction (LMI) has been established, the actual prevalence of dissection among patients with LMI may still be underestimated. Methods: Consecutive patients with acute pure LMI admitted between 2010 and 2021 were included. High-resolution vessel wall MRI (VWMRI) and/or transfemoral cerebral angiography (TFCA) were performed in a part of patients and were regarded as gold standard tests for diagnosis of dissection. Factors associated with definite dissection based on VWMRI or TFCA findings were assessed. Risk scoring for dissection was created based on multivariate logistic regression and applied to estimate the number of possible dissection. Results: Eighty-seven LMI patients were eligible and 47 (54.0%) of them underwent VWMRI (n=43) and/or TFCA (n=7). Among these 47 cases, 24 were definite dissection. Three out of 40 patients without gold standard tests were diagnosed with definite dissection based on conventional MRI findings. Preceding headache and normal body weight were independently associated with dissection in LMI patients. A risk scoring which includes age, body mass index, and headache predicted dissection with 91.7% sensitivity and 69.6% specificity (area under the receiver operating characteristic curve, 0.889; 95% confidence intervals, 0.802-0.977) in our population. Additional nine out of 37 patients without gold standard tests nor diagnosis of definite dissection in conventional MRI could be considered as possible dissection based on the scoring. Definite and possible dissections together comprised 41.4% (n=36) of LMI in our study. Conclusions: Arterial dissection may be more prevalent among LMI patients than reported before. Thorough diagnostic effort for dissection is necessary based on scrutinizing risk stratification.

Progression rates of medulla oblongata infarcts in clinical follow-up: A retrospective study

ObjectiveTo determine clinical progression rates in patients with medulla oblongata infarction (MOI). Materials and methodsThe data of patients diagnosed with MOI were analysed retrospectively. Dermographic characteristics of the patients; Age, gender, history and stroke etiology were evaluated. Radiological imagings were reviewed retrospectively. Intensive care unit (ICU) requirement, number of intubation days, failed extubation and death rates, good clinical outcome at discharge and 3 months [modified Rankin Scale (mRS 0–2)] and poor clinical outcome (mRS 3–6) rates were evaluated. In addition, the clinical results of patients with medial medullary infarction (MMI) and lateral medullary infarction (LMI) were compared. Results33 patients were included in the study, 22 (66.7 %) were male. The mean age of the patients was 72.0 (43.0–85.0). The characteristics of the patients (dermographic features, comorbidities, clinical symptoms, infarct localization, etc.) were evaluated. The results of MMI and LMI patients were compared. The intubation rate was 4 (44.4 %) in the MME group, while it was 8 (33.3 %) in the LME group. There was no statistically significant difference between the two groups in terms of failed extubation, tracheostomy, hospitalization and mortality rates. However, while discharge mRS was statistically significant between the two groups, the mRS at 3 months was not statistically significant. Twelve (36.4 %) of all patients were intubated due to severe clinical progression. In the clinical follow-up, 6 (50.0 %) of the intubated patients died, 3rd month mRS of 6 (50.0 %) patients who survived was 5. In all patients 3-month good clinical outcome rate was % 48,5. ConclusionIt should not be forgotten that life-threatening clinical progressions may develop at a considerable rate during the early treatment process of patients diagnosed with MOI.

Patient characteristics with negative diffusion-weighted imaging findings in acute lateral medullary infarction.

Diffusion-weighted imaging (DWI) on magnetic resonance imaging (MRI) shows limited sensitivity in the acute-phase brainstem infarctions, including lateral medullary infarction (LMI), and the detailed characteristics of acute LMI patients with initially negative DWI-MRI findings have not been reported previously. Therefore, we aimed to investigate the differences in the backgrounds or symptoms of acute LMI patients with initially negative findings in standard axial DWI-MRI and those with positive findings. In this retrospective cohort study, we collected the data for 35 consecutive acute LMI patients who were hospitalized in our hospital from January 2011 to December 2018. Initial standard axial DWI-MRI was assessed, and the patients were divided into positive and negative groups. The characteristics of the two groups were compared, and the usefulness of additional thin-slice coronal DWI-MRI was also investigated. Nine (26%) acute LMI patients were initially negative on standard axial DWI-MRI. The patients were independently associated with smoking history (78% vs. 23%, p = 0.021) and headache (78% vs. 31%, p = 0.046). Thin-slice coronal DWI-MRI showed positive findings in 50% of the patients with negative findings in standard axial DWI-MRI. All four patients with negative findings in both standard axial and thin-slice coronal DWI-MRI had smoking history and headache. Smoking history and headache were associated with initial negative results in standard axial DWI-MRI in acute LMI. Additional thin-slice coronal DWI-MRI was sometimes useful in detecting acute LMI. Follow-up MRI is important for patients showing negative findings in initial DWI-MRI.

Efficacy of Early Endoscopic Intervention for Restoring Normal Swallowing Function in Patients with Lateral Medullary Infarction.

Dysphagia is considered to be a significant barrier for recovery after lateral medullary infarction (LMI). However, there is still no gold standard treatment for dysphagia. The aim of this study was to explore an effect of an early treatment options for swallowing dysfunction after acute LMI. Medical records of acute LMI patients who had been admitted to the department of rehabilitation medicine from January 2014 to December 2017 were reviewed retrospectively. We compared the clinical efficacy of conventional dysphagia rehabilitation to early endoscopic intervention using either botulinum toxin injection into cricopharyngeal muscle or endoscopic balloon dilatation of the muscle. Outcomes, such as duration of parental feeding, albumin level at diet transition to enteral feeding, and complications, were analyzed. A total of 18 patients with LMI were included. While eight patients (8/9, 88.89%) in the endoscopic group were capable of orally ingesting their diet after intervention, the conversion from tube feeding to an oral diet was possible in only five patients (5/9, 55.56%) of the conventional group during hospitalization. However, the difference between the two groups was not significant (p-value ≤ 0.147, chi-square test). Only the final dietary level at the time of discharge was higher level in endoscopic group. The conversion interval from tube feeding to oral diet was also comparable between groups. There was no re-conversion from the oral diet to tube feeding in patients of either group during the median follow-up period of 20 months. Early endoscopic intervention may be a better option for dysphagia with LMI, compared to conventional dysphagia rehabilitation. However, a larger and prospective trial may be needed to confirm our observations.

Lateral Medullary Infarction with or without Extra-Lateral Medullary Lesions: What Is the Difference?

Background: Lateral medullary infarction (LMI) is not an uncommon disease. Although lesions are usually restricted to the lateral medullary area, some patients have additional infarcts in other parts of the brain. The clinical features and prognosis of isolated LMI (pure LMI, LMIpr) have been investigated. However, it remains unclear whether clinical characteristics, prognosis and factors associated with prognosis differ between patients with LMIpr and those with additional lesions (LMI plus, LMIpl). Methods: Patients with LMI identified by MRI were enrolled. The demographic and clinical characteristics, in-hospital outcome (intensive care unit [ICU] admission, pneumonia and modified Rankin scale [mRS] at discharge), and long-term residual symptoms (vertigo/dizziness, sensory disturbances, dysphagia) and outcomes (occurrence of stroke, acute coronary syndrome [ACS], death, and mRS at follow-up) were compared between LMIpr and LMIpl patients. Factors associated with poor functional outcome (mRS 2–6) at the follow-up were analyzed. Results: Among 248 LMI patients, 161 (64.9%) had LMIpr and 87 (35.1%) had LMIpl. During admission, patients with LMIpl more frequently experienced ICU care, pneumonia and had a higher discharge mRS (3 vs. 2; p < 0.001) than LMIpr patients. The occurrence of stroke, ACS, frequency of death and functional outcome was not different during follow-up. However, residual neurologic symptoms such as dizziness (p = 0.002), dysphagia (p = 0.04) and sensory symptoms (p < 0.001) were more frequent in LMIpr than in LMIpl patients. In LMIpr patients, the rostral location of LMI was associated with poor functional outcome (p = 0.041), whereas in LMIpl patients, the presence of medial posterior-inferior cerebellar artery lesion was associated with good functional outcome (p = 0.030). Conclusion: Although the short-term outcome is poorer in LMIpl than LMIpr patients, long-term residual symptoms are more common in LMIpr patients. The location of the LMI and extra-medullary lesion affects the long-term functional outcome of LMIpr and LMIpl patients respectively.

Ipsilateral hemiparesis in lateral medullary infarction: Clinical investigation of the lesion location on magnetic resonance imaging

BackgroundIn 1946, Opalski reported two cases of Wallenberg syndrome with ipsilateral hemiparesis (IH). His hypothesis seems to be based on the view that IH is caused by post-decussating pyramidal tract damage. Afterwards, other researchers proposed a different hypothesis that ipsilateral sensory symptoms of limbs (ISSL) or ipsilateral limb ataxia (ILA) caused by lateral medullary infarction (LMI) might lead to ipsilateral motor weakness. The present study is aimed to clarify whether IH in LMI patients is attributable mainly to ISSL/ILA or disruption of ipsilateral post-decussating pyramidal tract. MethodsThirty-two patients with acute LMI admitted during the last 13years were divided to IH Group (n=7) and Non-IH Group (n=25). Lesion location/distribution on MRI and neurological findings were compared between the two groups. ResultsLMI involved the lower medulla in all seven IH patients and 12 of 25 Non-IH patients. The lower medullary lesion extended to the cervico-medullary junction (CMJ) in four of seven IH patients and one of 12 Non-IH patients. Definitive extension to upper cervical cord (UCC) was confirmed in none of the patients. ISSL was found in two IH and three Non-IH patients all showing only superficial sensory impairments. ILA or hypotonia was observed in 57% of IH and 60% of Non-IH patients. ConclusionIH in LMI appears to be due mainly to post-decussating pyramidal tract damage at the lower medulla instead of ILA or ISSL participation.

Clinical Study of 46 Patients with Lateral Medullary Infarction

Lateral medullary infarction (LMI) exhibits a variety of clinical features. Various bulbar symptoms can occur in LMI. Neuroradiologic findings of 46 LMI patients were examined. Their infarcts were categorized into the rostral, middle, and caudal groups and were further subdivided into the anteromedial, anterolateral, lateral (L), and posterior regions. The middle medulla was the most common site (27 patients). Most lesions affected the L region alone (25 patients). Dysarthria and facial palsy occurred significantly more frequently in the rostral group than those in the caudal group. Severe truncal ataxia was significantly more common in the caudal group than that in the rostral group. Twenty-five of the 28 patients with severe truncal ataxia displayed vestibular symptoms; otherwise, the other 3 patients showed absence of vestibular symptoms. Soft palate paralysis occurred at a significantly high frequency in the patients with dysphagia and hoarseness compared with the patients without these 2 symptoms. Segmental sensory disturbance occurred in 5 patients, 4 of whom exhibited atypical patterns. The results of our comparisons between the rostral and caudal groups were consistent with those of previous studies. The presence of severe truncal ataxia without vestibular symptoms in LMI was atypical. An analysis of the bulbar symptoms indicated that the extent to which soft palate paralysis contributed to dysphagia was associated with the severity of ischemia in the nucleus ambiguus. The present study showed variability in clinical features of LMI, which was related to differences in the severity and the extent of ischemia in the lateral medulla.

High-Resolution Contrast-Enhanced 3D-Spoiled Gradient-Recalled Imaging for Evaluation of Intracranial Vertebral Artery and Posterior Inferior Cerebellar Artery in Lateral Medullary Infarction

Purpose : To determine whether high-resolution contrast-enhanced three dimensional imaging with spoiled gradientrecalled sequence (HR-CE 3D-SPGR) plays a meaningful role in the assessment of intracranial vertebral artery (ICVA) and posterior inferior cerebellar artery (PICA) in lateral medullary infarction (LMI). Materials and Methods: Twenty-five patients confirmed with LMI were retrospectively enrolled with approval by the IRB of our institute, and 3T MRI with HR-CE 3D-SPGR and contrast-enhanced magnetic resonance angiography (CE-MRA) were performed. Two radiologists who were blinded to clinical information and other brain MR images including diffusion weighted image independently evaluated arterial lesions in ICVA and PICA. The demographic characteristics, the area of LMI and cerebellar involvement were analyzed and compared between patients with arterial lesion in ICVA only and patients with arterial lesions in both ICVA and PICA on HR-CE 3D-SPGR. Results: Twenty-two of twenty-five LMI patients had arterial lesions in ICVA or PICA on HR-CE 3D SPGR. However twelve arterial lesions in PICA were not shown on CE-MRA. Concurrent cerebellar involvement appeared more in LMI patients with arterial lesion in ICVA and PICA than those with arterial lesion in ICVA alone (p = 0.069). Conclusion: HR-CE 3D-SPGR can help evaluate arterial lesions in ICVA and PICA for LMI patients.

Cardiovascular autonomic function in lateral medullary infarction

Even though the medulla contains the baroreceptor regulatory centers, few studies have focused on the autonomic dysfunction of lateral medullary infarction (LMI). Therefore, cardiac parasympathetic and sympathetic functions were compared in LMI patients and age-matched controls. We prospectively recruited 25 LMI patients who had ipsilateral Horner's sign and cardiac autonomic function testing without a history of diabetes, cardiac disease, or previous stroke. Parasympathetic function tests included beat-to-beat heart rate variation during deep breathing, 30:15 heart rate ratio testing while standing, and the valsalva ratio. Sympathetic function tests included blood pressure during active standing and sustained handgrip. The composite autonomic score (CAS) was measured as a total of 10 points; parasympathetic dysfunction was designated as ≥3 points in the parasympathetic subscores and sympathetic dysfunction as ≥2 points in the sympathetic subscores. Multiple regression analysis was performed to predict parasympathetic or sympathetic dysfunction. The mean age and stroke risk factors of the study population were not significantly different between the LMI group (n = 25) and control group (n = 29). However, cardiac autonomic functions were significantly different in the groups: parasympathetic dysfunction (14 vs. 4 patients, p = 0.011) and sympathetic dysfunction (3 vs. 13 patients, p = 0.008). In univariate analysis, male-gender (p = 0.011), right-side involvement (p = 0.035) and ventral involvement (p = 0.007) were significantly associated with parasympathetic dysfunction (CAS subscore ≥3). In multivariable analysis, the ventral involvement remained to be the independent predictor for parasympathetic dysfunction (OR 16.0; 95% CI 2.2-118.3, p = 0.007). This study suggests that LMI patients are susceptible to cardiac parasympathetic dysfunction, especially in the ventral medulla.

Prediction of Dysphagia Severity: An Investigation of the Dysphagia Patterns in Patients with Lateral Medullary Infarction

In order to identify the factors that influence the swallowing function in patients who develop Wallenberg syndrome (WS) following lateral medullary infarction (LMI), we examined various patient characteristics, including the passage pattern abnormality (PPA) of a bolus through the upper esophageal sphincter (UES). Fifty-four pure LMI patients with dysphagia participated in this study. PPA, defined as the failure of bolus passage through the UES corresponding to the intact side of the medulla, was identified during videofluorographic swallowing evaluations of each patient. On brain magnetic resonance imaging, the subjects' lesions were classified vertically into three levels and horizontally into seven levels in relation to the involvement of the ambiguous and/or solitary nuclei. Logistic regression analyses were performed for age, sex, PPA and the vertical and horizontal sites of the lesions. In terms of severity, 15 subjects were categorized as having mild dysphagia, 26 subjects were categorized as having moderate dysphagia and 13 were categorized as having severe dysphagia. Subjects with cephalic lesions, greater vertical spread of the lesion and PPA were more likely to have severe dysphagia. PPA and a greater vertical spread of the lesion were related to the severity of the functional outcome (p<0.01). The horizontal extent of the lesion was not strongly related to the prognosis. The presence of PPA in LMI patients is suggestive of abnormalities in the swallowing pattern and, in turn, damage to the medullary central pattern generator. The presence of PPA and a greater vertical spread of the lesion can be useful predictors of severe dysphagia.

Ischemic Vagus Nuclei Lesions and Hyperglycemia: A Study in 26 Patients with Lateral Medullary Infarction and Matched Controls

Background: Hyperglycemia is common after stroke in diabetic and nondiabetic patients. Furthermore, it has been associated with infarct expansion, worse functional outcomes and higher mortality. In a previous study, infarction of the insular region was related to higher poststroke glucose levels than infarcts in other cortical areas. Experimental studies in animal models suggested that the lower brainstem nuclei of the vagus nerve modulate insulin secretion. These nuclei are usually affected in lateral medullary infarction (LMI). We evaluated whether patients with lateral medullary stroke have worse poststroke glycemic control than other stroke patients. Methods: A hospital-based stroke registry was used to identify 26 patients from the years 2000 to 2010 who fulfilled the following inclusion criteria: (1) a first-ever stroke; (2) neurological deficits compatible with LMI; (3) MRI confirmation of an ischemic lesion of the lateral medulla involving the vagus nerve nuclei, and (4) no simultaneous infarcts. Patients were excluded if they were admitted to the hospital more than 24 h after stroke onset or died in the first 24 h after hospital admission. A control group of other stroke patients was randomly selected from the same stroke registry and over the same time period, matching for the age and gender of the LMI group. The average glycemia was compared between the two groups using a linear regression model adjusted for confounders. Glycated hemoglobin at admission was used to estimate prestroke glycemic control. Prestroke glycemic averages were then compared with poststroke glycemia for the two groups using the Wilcoxon signed test for related samples. Results: The average glycemia of the LMI patients in the first 24 h after stroke was 9.4 mmol/l (SD 3.2), and from 24 to 72 h it was 7.6 mmol/l (SD 2.8). In the comparison group, these values were 7.7 (SD 2.8) and 7.1 mmol/l (SD 2.7), respectively. As expected, diabetic patients had a significantly higher glycemia than nondiabetic patients (p < 0.0001). The adjusted linear regression model showed the average glycemia differences to be significant for the first 24 h (p = 0.001; R² = 55.6%) but not for the 24– 72 h period. The frequency of previous diabetes mellitus was similar in both groups. As compared to prestroke glycemic estimates, glycemia in lateral medullary stroke patients increased significantly more than in controls during the first 24 h after stroke (p = 0.01), but again there were no significant differences for the 24–72 h period. Conclusions: This study suggests that ischemic lesions of the vagus nerve nuclei are associated with worse early poststroke glycemic control than stroke in other locations. Confirmation of this hypothesis and the long-term implications of glucose control impairment warrant further prospective studies.

Characteristics of stroke mechanisms in patients with medullary infarction

Few studies have focused on the mechanisms underlying medullary infarctions. Our aim in this study was to investigate stroke mechanisms in patients with medullary infarctions and to determine the clinical, radiological and laboratory characteristics of these patients with different underlying stroke etiologies. Consecutive patients with medullary infarction were analysed. Stroke mechanisms were classified as large artery disease (LAD), cardiogenic embolism (CE), small vessel disease (SVD), arterial dissection or undetermined etiology. Clinical, radiological and laboratory factors were analysed according to the location of the lesion and stroke mechanisms. A total of 77 patients were enrolled in this study. Amongst them, 53 (68.8%) patients had lateral medullary infarction (LMI), 22 (28.6%) had medial medullary infarction (MMI), and the remaining 2 (2.6%) had hemimedullary infarction. In both LMI and MMI patients, LAD was the most frequently encountered stroke mechanism. Arterial dissection was the second most common cause followed by SVD and CE in patients with LMI, whereas SVD was more frequently observed (P<0.001) and dissection and CE were less prevalent (P<0.001 and P=0.024, respectively) in MMI than in LMI. Regarding differences amongst stroke etiologies, patients with dissection were younger and had a significantly lower incidence of metabolic syndrome (P=0.002 and P=0.009, respectively) than patients with LAD and SVD. Patients in the LAD (19/34, 60%) and dissection groups (12/14, 75%) had abnormal perfusion-weighted MRI (PWI) findings, whereas all patients with SVD (9/9) had normal PWI findings (P<0.001). Stroke mechanisms in medullary infarction differ between LMI and MMI. Clinical and radiological characteristics, especially PWI features, are helpful in discriminating the etiologies of stroke in these patients.

Clinical Features of Lateral Medullary Infarction with Ipsilateral Hemiparesis (P03.026)

Objective: To clarify clinical features and lesion distribution of lateral medullary infarction (LMI) with ipsilateral hemiparesis (IH). Background LMI with hemiparesis ipsilateral to the lesion was first reported by Opalski in 1946. He explained IH with the damage of pyramidal tracts at the level of upper cervical cord. However, little is known about the clinical features and MRI profiles. Design/Methods: We performed a single-hospital-based retrospective study. Subjected were 69 LMI patients admitted to our hospital within a week after stroke between January 1998 and July 2011. All the LMI lesions were confirmed with diffusion-weighted MRI. Excluded were 16 patients who had other lesions possibly causing IH or did not have detailed clinical information. The remaining 53 patients (mean age 59.9 yrs, 38 males) were divided into two groups, IH and non-IH. The medulla oblongata and upper cervical cord were divided into 5 areas (upper medulla, middle medulla, lower medulla, cervico-medullary junction and upper cervical cord). Results: Seventeen patients (32.1 %) showed IH (IH group), while the other 36 had no motor weakness (non-IH group). Clinical profiles including age and gender were similar between the two groups. The severity of paresis was mild to moderate in all IH patients. The incidence of vertebral artery dissection was significantly higher in IH group than in non-IH group (58.5% vs. 27.8%, p Conclusions: IH was a relatively common symptom in LMI. The lower medulla instead of the upper cervical cord was most frequently involved in our IH patients. LMI with IH may represent distinct clinical entity characterized by a long extending lower medullary lesion. Disclosure: Dr. Uemura has nothing to disclose. Dr. Uno has nothing to disclose. Dr. Umesaki has nothing to disclose. Dr. Miyashita has nothing to disclose. Dr. Nagatsuka has nothing to disclose. Dr. Toyoda has nothing to disclose. Dr. Minematsu has nothing to disclose. Dr. Naritomi has nothing to disclose.

Dysphagia in unilateral medullary infarction

To study dysphagia in pure, unilateral medullary infarction using video fluoroscopic swallowing (VFS) tests and to compare the results between lateral medullary infarction (LMI) and medial medullary infarction (MMI). We studied 46 patients with medullary infarction (37 LMI, 9 MMI). Based on the MRI findings, each LMI was classified rostrocaudally as either a rostral or caudal lesion, and horizontally as either a superficial (lateral + dorsal) or nonsuperficial lesion. Each MMI was assigned to either a deep (lesion extending to the dorsal surface) or superficial lesion group. VFS examination was conducted and an 8-point scale was used for assessing the severity of dysphagia. Based on these results, dysphagia was classified as: 1) problems on timing of hyolaryngeal excursion (PT), and 2) problems on range of hyolaryngeal excursion (PR). Dysphagia was more frequent (p < 0.05) in MMI patients (78%) than in LMI patients (35%). Among the LMI patients, dysphagia was more frequent (p < 0.01) and severe (p < 0.01) in the rostral than in the caudal group and in the nonsuperficial than in the superficial group. In the MMI group, there was no difference in the frequency of dysphagia between the deep and superficial groups. Regarding the characteristics of dysphagia, seven (54%) of the LMI patients had PR, five (38%) had PT, and one (8%) had both. For the MMI patients, PT was frequent (86%) but PR was present in only one patient (14%). Five MMI patients (71%) showed no responses to penetration or aspiration, and silent dysphagia was observed in only four LMI patients (31%). Dysphagia is as frequent and severe in medial medullary infarction (MMI) as in lateral medullary infarction (LMI) patients. The types and characteristics of dysphagia are different between the LMI and MMI patients, implicating the rationale for a different treatment strategy.

Differences in long term sensory sequelae between lateral and medial medullary infarction

Differences in long term sensory sequelae between lateral and medial medullary infarction J.S. Kim, S. Choi-Kwon (Seoul, Korea) Background To compare long term sensory sequelae of the lateral medullary infarction (LMI) and medial medullary infarction (MMI). Methods We studied 55 (41 LMI and 14 MMI) patients who were followed up > 6 months. The nature and intensity of sensory symptoms were assessed by McGill-Melzack pain questionnaire and visual analogue scale, respectively. Results After the mean follow up of 21 months, sensory symptoms were the most important, and the second most important sequelae in LMI patients and MMI patients, respectively. In LMI patients, the symptoms were most often described as cold (38%), numb (29%) and burning (27%) while MMI patients described them as numb (60%), squeezing (30%) and cold (10%). LMI patients significantly more often cited cold environment as an aggravating factor, and more often had a delayed-onset pain than MMI patients. Conclusions: The nature, the mode of onset and aggravating factors of the sensory sequelae are different between LMI and MMI patients, which may be related to selective involvement of the spinothalamic tract by the former and the medial lemniscus by the latter. We suggest that the mechanisms for central post-stroke pain may differ according to the site of damages on the sensory tracts. NXY-059: Neuroprotective Effects in a Rat Focal Stroke