Aspiration subsequent to a pure medullary infarction: lesion sites, clinical variables, and outcome

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.

Relationship between Swallowing Pressure and Saliva Residue on Endoscopic Evaluation in Pharyngeal Dysphagia

OBJECTIVE

In pharyngeal dysphagia, poor pharyngeal contraction and upper esophageal sphincter (UES) dysfunction result in post-swallow saliva residue (SR). This study aimed to clarify the relationship between swallowing pressure and SR in the valleculae and piriform sinuses on flexible endoscopic evaluation of swallowing (FEES).

METHODS

Pharyngeal dysphagia patients with Wallenberg syndrome were included. Amounts of post-swallow SR in the valleculae and piriform sinuses were classified into four grades using SR scores based on FEES. The Hyodo score was also calculated to evaluate swallowing function. High-resolution manometric data in the nasopharyngeal, oropharyngeal, hypopharyngeal, oro-hypopharyngeal, and UES zones on swallowing were obtained for comparison with SR and Hyodo scores.

RESULTS

Of the 31 recruited, data from 26 patients who successfully underwent FEES and manometry were analyzed. Vallecular SR scores were strongly negatively correlated with a maximum pressure of the oropharynx (r = -0.52, p = 0.006), distal contractile integrals (DCI) of the oropharynx (r = -0.52, p = 0.007), and DCI of the oro-hypopharynx (r = -0.55, p = 0.004). Hyodo scores for parameters 1 and 4 (corresponding to salivary pooling and pharyngeal clearance, respectively) were strongly negatively correlated with a maximum hypopharyngeal pressure (r = -0.57, p = 0.002) and strongly positively correlated with peristaltic velocity (r = 0.53, p = 0.007), respectively. SR scores and Hyodo scores related to SR were not correlated with pressure data of the UES.

CONCLUSION

Manometric analysis of our SR scoring method using FEES revealed that a higher amount of SR in the valleculae, but not in the piriform sinuses, is associated with weaker pharyngeal pressure in pharyngeal dysphagia, especially at the oropharyngeal level.

LEVEL OF EVIDENCE

4 Laryngoscope, 2024.

Compensatory swallowing methods in a patient with dysphagia due to lateral medullary syndrome-vacuum and prolonged swallowing: A case report

INTRODUCTION

The nature of pharyngeal swallowing function during the course of recovery of dysphagia due to lateral medullary syndrome (LMS) is unclear. Vacuum swallowing is a compensatory swallowing method that improves the pharyngeal passage of a bolus by creating negative pressure during swallowing in the esophagus in patients with dysphagia due to LMS. We present a case involving a patient with dysphagia due to LMS who involuntarily acquired a swallowing method with prolonged and increased pharyngeal contraction and vacuum swallowing.

PATIENT CONCERNS

We report a unique case involving a 52-year-old patient with dysphagia due to LMS. His dysphagia was severe but improved gradually with swallowing rehabilitation. The patient involuntarily acquired a swallowing method with prolonged and increased pharyngeal contraction and vacuum swallowing.

DIAGNOSIS

The patient presented with dysphagia due to left LMS. A videofluoroscopic examination of swallowing revealed pharyngeal residue.

INTERVENTIONS

Forty-five days after the onset of the dysphagia, the swallowing pressure along the pharynx and esophagus was measured using high-resolution manometry.

OUTCOMES

Vacuum swallowing was observed in six out of 19 swallows (32.5%). The velopharyngeal contractile integral (CI) and mesohypopharyngeal CI values increased during swallowing, reflecting prolonged and increased pharyngeal contraction. We named this swallowing method "prolonged swallowing."

CONCLUSION

The findings in this case indicate that vacuum and prolonged swallowing may be compensatory swallowing methods observed in individuals recovering from dysphagia due to LMS. Further research is needed to clarify the relationship between these swallowing methods and the pathophysiology, prognosis, and treatment of dysphagia in patients with LMS.

Structural Connectivity Affecting Aspiration After Stroke

Aspiration after stroke is associated with pneumonia and mortality. In this study, we investigated brain structural connectivity associated with aspiration after unilateral supratentorial stroke. Patients on oral feeding after stroke were divided into liquid aspiration (22 patients) and normal (18 patients) groups based on videofluoroscopic swallowing studies. Voxel-based lesion-symptom mapping and voxel-wise group comparison of fractional anisotropy, mode of anisotropy, and mean diffusivity maps were conducted. Voxel-based lesion-symptom mapping revealed no significant lesion differences between groups. The aspiration group showed significantly increased fractional anisotropy and mode of anisotropy in the anterior limb and the genu of the internal capsule in the right hemisphere. In contrast, the normal group showed significantly increased mean diffusivity, mainly in the superior longitudinal fasciculus in the right hemisphere (P < 0.05). Degeneration of the internal capsule in the right hemisphere was found to affect aspiration after stroke.

Vocal cord paresis on CTA - A novel tool for the diagnosis of lateral medullary syndrome

BACKGROUND

Diagnosis of lateral medullary syndrome (LMS) is often delayed due to elusive clinical presentations and frequently non-revealing neuroimaging tests. We aimed to investigate the use of ipsilateral vocal cord paresis (VCP) identified on neck computed tomography angiography (CTA) as an early diagnostic sign for LMS.

METHODS

Medical records were queried for patients admitted with LMS between 1/2012 and 10/2020. A control group of patients undergoing CTA for transient or no neurological symptoms was matched for sex and age. Clinical data were collected by a stroke neurologist. Two neuroradiologists independently and blindly assessed CTA images for radiological signs of VCP.

RESULTS

Fifteen LMS and 15 control patients were included in the analysis. Median time from arrival to LMS diagnosis was 29.4 h [IQR 7,47] and twice as long in patients who suffered aspiration pneumonia. Thrombolysis rate was 0% in LMS patients versus 14.5% in general stroke patients. Dysphonia was noted in the emergency department in three (20%) patients, whereas all 15 patients had radiological signs of VCP on CTA. Medialization of a true vocal cord was the most sensitive (100%) and specific (80-87%) sign for LMS, with good inter-rater agreement (kappa 0.66). Timely detection of VCP on CTA could have shortened median time to LMS diagnosis by 14 h and enabled thrombolytic therapy in 3 (20%) patients.

CONCLUSIONS

VCP on CTA is a valuable sign for the diagnosis of LMS. If detected early, it may enable reperfusion therapy and prevent aspiration pneumonia, consequently saving life and diminishing disability.

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.

Dysphagia prognosis prediction via corticobulbar tract assessment in lateral medullary infarction: a diffusion tensor tractography study

We investigated the capacity for dysphagia prognosis prediction using diffusion tensor tractography (DTT) to assess the state of the corticobulbar tract (CBT) during the initial period following lateral medullary infarction (LMI). Twenty patients with LMI and 20 control subjects were recruited for this study. The patients were classified into two subgroups: subgroup A (16 patients with nasogastric tube required for six months or less after LMI onset) and subgroup B (4 patients with nasogastric tube required for more than six months after onset). DTT was used to reconstruct the CBTs of each patient and control subject, and the fractional anisotropy (FA) and tract volume (TV) measurements were obtained. In the affected hemisphere, the FA value of the CBT was significantly lower in subgroup B than in subgroup A and the control group (p < 0.05), with no significant difference between subgroup A and the control group. In the affected and unaffected hemispheres, the TV values of CBT in subgroups A and B were lower than those of the control group (p < 0.05), with no significant difference between subgroups A and B. In addition, among the four patients of subgroup B, reconstruction of the CBT was not possible in three patients, and the remaining patients exhibited on old lesion in the corona radiate involving descending pathway of the CBT in the affected hemisphere. We found that the injury severity of the CBT in the affected hemisphere appeared to be related to a poor dysphagia prognosis following LMI. Our results suggest that evaluation of the CBT state during the early post-LMI could be useful for dysphagia prognosis prediction.

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.

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.

Which Factors Affect the Severity of Dysphagia in Lateral Medullary Infarction?

The purpose of this study was to identify factors associated with the severity of dysphagia after lateral medullary infarction (LMI). Patients with dysphagia after lateral medullary infarction who were admitted to a rehabilitation unit were included and divided into two groups (non-severe vs. severe). Severe dysphagia was defined as the condition showing decreased bilateral pharyngeal constriction without esophageal passage in a videofluoroscopic swallowing study that initially required enteral tube feeding. Their clinical data (age, sex, lesion side, duration of the illness, penetration-aspiration scale, functional oral intake scale, Modified Barthel index, National Institutes of Health Stroke Scale, and anatomical lesion on diffusion-weighted MRI) were compared to find differences between the two groups. Twelve patients had absence of esophageal passage among a total of 30 patients with dysphagia after LMI. Only anatomical lesion location and extent were significantly different between the two groups. The severe group showed posterolateral involvement in the upper and lower parts of the medulla. Otherwise, there were no significant differences between the two groups. The location and extent of involvement in the medulla were the most important factors associated with the severity of dysphagia after LMI.

Clinical course and outcome in patients with severe dysphagia after lateral medullary syndrome

Background

The objective of this study was to investigate the clinical course and final outcome in patients afflicted with severe dysphagia following a diagnosis of lateral medullary syndrome (LMS).

Methods

The patients with severe dysphagia after LMS admitted to a rehabilitation unit were included and their respective clinical data were prospectively collected. The criteria of ‘severe dysphagia’ was defined as the condition that showed decreased pharyngeal constriction with no esophageal passage in a videofluoroscopic swallowing study (VFSS) and initially required enteral tube feeding. The data included VFSS findings, types of diet and postural modification, penetration-aspiration scale (PAS) and functional oral intake scale (FOIS).

Results

A total of 11 patients were included and VFSS was performed every 2 weeks after stroke onset. Esophageal passage began to show at an average 34.7 ± 18.3 days, and the patients were able to begin consuming a partial oral diet with postural modification. It was 52.2 ± 21.8 days till they were advanced to a full oral diet. PAS and FOIS were significantly improved over time.

Conclusions

Patients with severe dysphagia after LMS were able to tolerate a partial oral diet at about 5 weeks following onset, and they were advanced to a normal diet after 10 weeks. This clinical course might help in predicting the prognosis, as well as assist in making practical decisions regarding a rehabilitation program.

Comparison of dysphagia outcomes between rostral and caudal lateral medullary infarct patients

OBJECTIVE

A detailed knowledge of dysphagia outcomes in lateral medullary infarct (LMI) patients would enable proper establishment of swallowing therapy goals and strategies. However, little is known about the impact of infarct location on dysphagia outcomes in patients with LMI.

METHODS

Twenty patients with rostral LMI (rostral group) and 20 patients with caudal LMI (caudal group) participated in the study. All patients underwent swallowing therapy, which included compensatory treatments and strengthening exercises, for >3 months. Dysphagia evaluation was performed twice (during the subacute stage and six months after stroke onset) using videofluoroscopic swallowing studies. Dysphagia degree was assessed using the functional dysphagia scale (FDS), the penetration-aspiration scale (PAS) and the American Speech-Language-Hearing Association (ASHA) National Outcome Measurement System (NOMS) swallowing scale.

RESULTS

In the subacute stage, the rostral group had significantly higher FDS and PAS scores and a significantly lower ASHA NOMS score than the caudal group. Patients from both groups showed significant improvement from the initial evaluation to the six-month evaluation. There were no significant differences in these scale scores between the two groups at the six-month evaluation.

CONCLUSION

In the subacute stage, patients in the rostral group had more severe dysphagia than those in the caudal group. Dysphagia improved in both groups after 3-6 months of swallowing therapy. At six months after onset, there were no significant differences in dysphagia severity between the two groups. Recovery from dysphagia after LMI was observed regardless of the infarct location.

Axonopathy in the Central Nervous System Is the Hallmark of Mice with a Novel Intragenic Null Mutation of Dystonin

Dystonia musculorum is a neurodegenerative disorder caused by a mutation in the dystonin gene. It has been described in mice and humans where it is called hereditary sensory autonomic neuropathy. Mutated mice show severe movement disorders and die at the age of 3-4 weeks. This study describes the discovery and molecular, clinical, as well as pathological characterization of a new spontaneously occurring mutation in the dystonin gene in C57BL/6N mice. The mutation represents a 40-kb intragenic deletion allele of the dystonin gene on chromosome 1 with exactly defined deletion borders. It was demonstrated by Western blot, mass spectrometry, and immunohistology that mice with a homozygous mutation were entirely devoid of the dystonin protein. Pathomorphological lesions were restricted to the brain stem and spinal cord and consisted of swollen, argyrophilic axons and dilated myelin sheaths in the white matter and, less frequently, total chromatolysis of neurons in the gray matter. Axonal damage was detected by amyloid precursor protein and nonphosphorylated neurofilament immunohistology. Axonopathy in the central nervous system (CNS) represents the hallmark of this disease. Mice with the dystonin mutation also showed suppurative inflammation in the respiratory tract, presumably due to brain stem lesion-associated food aspiration, whereas skeletal muscles showed no pathomorphological changes. This study describes a novel mutation in the dystonin gene in mice leading to axonopathy in the CNS. In further studies, this model may provide new insights into the pathogenesis of neurodegenerative diseases and may elucidate the complex interactions of dystonin with various other cellular proteins especially in the CNS.

Dysphagia and aspiration as the only manifestations of a stroke

A 56-year-old patient was admitted to our hospital, presenting with dysphagia as the only symptom. He was very concerned about this difficulty in swallowing. Diseases of the upper digestive tract were suspected, but further investigations revealed a neurological disorder. He had suffered a brain stem stroke and, as a consequence, developed an aspiration pneumonia. What seemed a digestive disorder was indeed a brain stem stroke, therefore we had to deal with the diverse impacts of this condition.

Dysphagia May Be an Independent Marker of Poor Outcome in Acute Lateral Medullary Infarction

BACKGROUND AND PURPOSE

The functional recovery after the lateral medullary infarction (LMI) is usually good. Little is known about the prognostic factors associated with poor outcome following acute LMI. The aim of this study was to identify the factors associated with poor long-term outcome after acute LMI, based on experiences at a single center over 11 years.

METHODS

A consecutive series of 157 patients with acute LMI who were admitted within 7 days after symptom onset was evaluated retrospectively. Clinical symptoms were assessed within 1 day after admission, and outcomes were evaluated over a 1-year period after the initial event. The lesions were classified into three vertical types (rostral, middle, and caudal), and the patients were divided into two groups according to the outcome at 1 year: favorable [modified Rankin Scale (mRS) score ≤1] and unfavorable (mRS score ≥2).

RESULTS

Of the 157 patients, 93 (59.2%) had a favorable outcome. Older age, hypertension, dysphagia, requirement for intensive care, and pneumonia were significantly more prevalent in the unfavorable outcome group. The frequencies of intensive care (13%) and mortality (16.7%) were significantly higher in the rostral lesion (p=0.002 and p=0.002). Conditional logistic regression analysis revealed that older age and initial dysphagia were independently related to an unfavorable outcome at 1 year [odds ratio (OR)=1.04, 95% confidence interval (95% CI)=1.001-1.087, p=0.049; OR=2.46, 95% CI=1.04-5.84, p=0.041].

CONCLUSIONS

These results suggest that older age and initial dysphagia in the acute phase are independent risk factors for poor long-term prognosis after acute LMI.

Dysphagia Management in Acute and Sub-acute Stroke

Swallowing dysfunction is common after stroke. More than 50% of the 665 thousand stroke survivors will experience dysphagia acutely of which approximately 80 thousand will experience persistent dysphagia at 6 months. The physiologic impairments that result in post-stroke dysphagia are varied. This review focuses primarily on well-established dysphagia treatments in the context of the physiologic impairments they treat. Traditional dysphagia therapies including volume and texture modifications, strategies such as chin tuck, head tilt, head turn, effortful swallow, supraglottic swallow, super-supraglottic swallow, Mendelsohn maneuver and exercises such as the Shaker exercise and Masako (tongue hold) maneuver are discussed. Other more recent treatment interventions are discussed in the context of the evidence available.

Hospital acquired pneumonia is linked to right hemispheric peri-insular stroke

PURPOSE

Hospital acquired pneumonia (HAP) is a major complication of stroke. We sought to determine associations between infarction of specific brain regions and HAP.

METHODS

215 consecutive acute stroke patients with HAP (2003-2009) were carefully matched with 215 non-pneumonia controls by gender, then NIHSS, then age. Admission imaging and binary masks of infarction were registered to MNI-152 space. Regional atlas and voxel-based log-odds were calculated to assess the relationship between infarct location and the likelihood of HAP. An independently validated penalized conditional logistic regression model was used to identify HAP associated imaging regions.

RESULTS

The HAP and control patients were well matched by gender (100%), age (95% within 5-years), NIHSS (98% within 1-point), infarct size, dysphagia, and six other clinical variables. Right hemispheric infarcts were more frequent in patients with HAP versus controls (43.3% vs. 34.0%, p = 0.054), whereas left hemispheric infarcts were more frequent in controls (56.7% vs. 44.7%, p = 0.012); there was no significant difference between groups in the rate of brainstem strokes (p = 1.0). Of the 10 most infarcted regions, only right insular cortex volume was different in HAP versus controls (20 vs. 12 ml, p = 0.02). In univariate analyses, the highest log-odds regions for pneumonia were right hemisphere, cerebellum, and brainstem. The best performing multivariate model selected 7 brain regions of infarction and 2 infarct volume-based variables independently associated with HAP.

CONCLUSIONS

HAP is associated with right hemispheric peri-insular stroke. These associations may be related to autonomic modulation of immune mechanisms, supporting recent hypotheses of stroke mediated immune suppression.

Dysphagia after Stroke: an Overview

Dysphagia affects the vast majority of acute stroke patients. Although it improves within 2 weeks for most, some face longstanding swallowing problems that place them at risk for pneumonia, malnutrition, dehydration, and significantly affect quality of life. This paper discusses the scope, the disease burden, and the tools available for screening and formal evaluation of dysphagia. The most common and recently developed treatment interventions that might be useful in the treatment of this population are discussed.

Laterality of bolus passage through the pharynx in patients with unilateral medullary infarction

Laterality of bolus passage in the pharynx is often seen in patients with medullary infarction. We evaluated the dominant side of bolus passage in the pharynx and investigated the factors that cause the passage to dominantly occur on the affected side. Forty-one patients (35 men and 6 women, 64 ± 9 years) with unilateral medullary infarction participated in this study. Bolus passage of 4 mL of thick liquid was evaluated in 3 regions (oropharyngeal, thyropharyngeal, and cricopharyngeal) and classified into 4 patterns (dominantly on the unaffected side [UAS], on both sides without clear laterality [BS], dominantly on the affected side [AS], and nonpassage of the bolus [NP]) by videofluoroscopic examination of swallowing. The bolus passages were as follows: UAS, BS, and AS occurred in 2, 32, and 7 patients in the oropharyngeal region; UAS, BS, and AS occurred in 5, 20, and 16 patients in the thyropharyngeal region; and UAS, BS, AS, and NP occurred in 11, 9, 10, and 11 patients in the cricopharyngeal region, respectively. In the thyropharyngeal region, the proportion of patients in whom the swallowing reflex occurred when the bolus was in the oropharynx and the proportion of patients with unilateral pharyngeal constrictor paralysis were greater in patients whose bolus passage was AS than in patients whose passage was BS. This suggests that the bolus predominantly passed through the affected side of the thyropharyngeal portion because of the asymmetry of pharyngeal contraction during swallowing in the early period after onset.

Lesion of the nucleus solitarius leads to impaired laryngeal sensation in bulbar palsy patients

BACKGROUND

In order to clarify the laryngeal sensation of bulbar palsy patients, we studied the relationship between laryngopharyngeal sensation and brainstem lesion in patients with dysphagia caused by bulbar palsy.

METHODS

Fifteen patients with lateral medullary infarction and dysphagia were included in this study. We performed laryngeal sensory test using the flexible laryngoscope and probes method previously developed by Yaguchi et al. The test sites included the right and left tip of the laryngeal surface of the epiglottis and bilateral arytenoid regions. Lesion sites were identified by magnetic resonance imaging and classified horizontally according to Kim's classification. We also used the anatomical atlas Cytoarchitecture of the Human Brain Stem to determine whether the lesions included the nucleus solitarius and nucleus ambiguus.

RESULTS

Eight cases had normal sensation and 7 cases had decreased sensation of the affected side of the epiglottis and arytenoid region. The lesions of decreased laryngeal sensation group were classified horizontally as large type or dorsal type and included the nucleus solitarius. Decreased laryngeal sensation was significantly correlated with lesions that included the nucleus solitarius (Fisher exact test; P = .026).

CONCLUSIONS

This study clarifies that patients with dysphagia caused by bulbar palsy may present with laryngeal sensory impairment of the affected side and laryngopharyngeal movement disorder. The important finding is that damage to both the nucleus solitarius and ambiguus cause dysphagia accompanied by decreased laryngeal sensation and that the lesions are relatively extensive and affect the middle level of the dorsal medulla.

Oropharyngeal dysphagia after stroke: incidence, diagnosis, and clinical predictors in patients admitted to a neurorehabilitation unit

OBJECTIVE

We analyzed patients with stroke in a neurorehabilitation unit to define incidence of dysphagia, compare clinical bedside assessment and videofluoroscopy (VFS), and define any correlation between dysphagia and clinical characteristic of patients.

METHODS

In all, 151 consecutive inpatients with recent ischemic or hemorrhagic stroke were enrolled.

RESULTS

Dysphagia was clinically diagnosed in 62 of 151 patients (41%). A total of 49 patients (79% of clinically dysphagic patients) underwent VFS. Six patients clinically suggested to be dysphagic had a normal VFS finding. The correlation between clinical and VFS diagnosis of dysphagia was significant (r = 0.6505). Penetrations and aspirations were observed, respectively, in 42.8% and 26.5% of patients with dysphagia, with 12.2% classified as silent. Lower respiratory tract infections were observed in 5.9%, more frequently in patients with dysphagia (30%). Dysphagia was not influenced by type of stroke. Cortical stroke of nondominant side was associated with dysphagia (P = .0322) and subcortical nondominant stroke showed a reduced frequency of dysphagia (P = .0008). Previous cerebrovascular disease resulted associated to dysphagia (P = .0399). Patients with dysphagia had significantly lower functional independence measurement (FIM) and level of cognitive functioning on admission and lower FIM on discharge, longer hospital stay, and more frequent malnutrition, and they were more frequently aphasic and dysarthric. Percutaneous endoscopic gastrostomy was used in 18 of 151 patients (11.9%) (41.8% of patients with VFS-proved dysphagia).

CONCLUSIONS

Dysphagia occurs in more than a third of patients with stroke admitted to rehabilitation. Clinical assessment demonstrates good correlation with VFS. The grade of dysphagia correlates with dysarthria, aphasia, low FIM, and level of cognitive functioning. Large cortical strokes of nondominant side are associated with dysphagia.

Accuracy of clinical judgment of the chin-down posture for dysphagia during the clinical/bedside assessment as corroborated by videofluoroscopy in adults with acute stroke

Speech-language pathologists tend to rely on the noninstrumental swallowing evaluation in making recommendations about a patient's diet and management plan. The present study was designed to examine the sensitivity and specificity of the accuracy of using the chin-down posture during the clinical/bedside swallowing assessment. In 15 patients with acute stroke and clinically suspected oropharyngeal dysphagia, the correlation between clinical and videofluoroscopic findings was examined. Results identified that there is a difference in outcome prediction using the chin-down posture during the clinical/bedside assessment of swallowing compared to assessment by videofluoroscopy. Results are discussed relative to statistical and clinical perspectives, including site of lesion and factors to be considered in the design of an overall treatment plan for a patient with disordered swallowing.

Disorders of swallowing: palliative care

This article defines palliative care for swallowing disorders as treatment for severe and chronic dysphagia or intractable aspiration when the recovery of normal swallowing is not anticipated and attempts to restore normal swallowing have been unsuccessful. Palliative treatment for dysphagia is not only for the dying patient because patients with difficulty swallowing can live for a long time. Palliative care for dysphagia is aimed at maximizing swallowing function, maintaining pulmonary health, and supporting healthy nutrition despite the impaired ability to swallow. When despite all attempts at intervention a patient becomes totally unable to swallow, the goal of therapy changes toward finding ways to provide adequate nutrition for the patient.

Impaired opening of the upper esophageal sphincter in patients with medullary infarctions

The aim of this study was to report on nine dysphagic patients with medullary infarction and to evaluate swallowing characteristics based on the location of the lesions.We retrospectively reviewed the medical records of these nine patients. The medullary lesions were midlateral (three patients), dorsolateral (one patient), inferodorsolateral (four patients), and paramedian (one patient). The levels of the lesions were upper (four patients), middle (two patients), upper and middle (two patients), and middle and lower medulla (one patient). Dysphagia after medullary infarction was more common in patients with upper or middle medullary level and dorsolateral medullary level lesions. The common findings on videofluoroscopic swallowing studies in patients with lateral medullary infarctions were impaired upper esophageal sphincter opening, aspiration from pyriform sinuses' residue caused by pharyngeal weakness, and multiple swallowing to clear boluses from the pharynx to the esophagus. In patients with medullary infarctions, the lesion levels and loci and their related clinical findings can be useful in predicting dysphagia and aspiration. Because severe dysphagia with serious complication is very common in patients with medullary infarctions, active diagnostic and therapeutic approaches are needed.

Swallowing and dysphagia rehabilitation: translating principles of neural plasticity into clinically oriented evidence

PURPOSE

This review presents the state of swallowing rehabilitation science as it relates to evidence for neural plastic changes in the brain. The case is made for essential collaboration between clinical and basic scientists to expand the positive influences of dysphagia rehabilitation in synergy with growth in technology and knowledge. The intent is to stimulate thought and propose potential research directions.

METHOD

A working group of experts in swallowing and dysphagia reviews 10 principles of neural plasticity and integrates these advancing neural plastic concepts with swallowing and clinical dysphagia literature for translation into treatment paradigms. In this context, dysphagia refers to disordered swallowing associated with central and peripheral sensorimotor deficits associated with stroke, neurodegenerative disease, tumors of the head and neck, infection, or trauma.

RESULTS AND CONCLUSIONS

The optimal treatment parameters emerging from increased understanding of neural plastic principles and concepts will contribute to evidence-based practice. Integrating these principles will improve dysphagia rehabilitation directions, strategies, and outcomes. A strategic plan is discussed, including several experimental paradigms for the translation of these principles and concepts of neural plasticity into the clinical science of rehabilitation for oropharyngeal swallowing disorders, ultimately providing the evidence to substantiate their translation into clinical practice.

Normal swallowing and functional magnetic resonance imaging: a systematic review

Unknowns about the neurophysiology of normal and disordered swallowing have stimulated exciting and important research questions. Previously, these questions were answered using clinical and animal studies. However, recent technologic advances have moved brain-imaging techniques such as functional magnetic resonance imaging (fMRI) to the forefront of swallowing neurophysiology research. This systematic review has summarized the methods and results of studies of swallowing neurophysiology of healthy adults using fMRI. A comprehensive electronic and hand search for original research was conducted, including few search limitations to yield the maximum possible number of relevant studies. The participants, study design, tasks, and brain image acquisition were reviewed and the results indicate that the primary motor and sensory areas were most consistently active in the healthy adult participants across the relevant studies. Other prevalent areas of activation included the anterior cingulate cortex and insular cortex. Review limitations and suggested future directions are also discussed.

Microsurgical considerations of the anterior spinal and the anterior-ventral spinal arteries

BACKGROUND

There are few data describing the microanatomy of the anterior-ventral spinal (AVSA) and anterior spinal arteries (ASA) and discussing their clinical and surgical implications. We describe the anatomical features of this arterial complex, and highlight their use when planning and performing surgical approaches to lesions involving the ventral aspect of the medulla and the foramen magnum.

METHOD

The microsurgical anatomy and branching pattern of the AVSA and the ASA from fifty human cadaver brain stems is described using a surgical microscope.

RESULTS

We found one anterior-ventral spinal artery at each side in 30 of the brain stems (60%). The ASA was a direct branch emerging from the left vertebral artery (VA) in 15 (30%), from the right VA in 4 (8%), and from the basilar artery (BA) in one brain stem (2%). The previously described as "typical pattern" of the junction of the AVS arteries from both sides, was observed only in 9 brain stems (18%). The anterior communicating spinal artery (ACoSA) was observed in 15 brain stems (30%). Also multiple ACoS arteries were described in one brain stem. Both, the AVSA and the ASA were observed to send long circumferential branches that supplied irrigation to the olive in 42 (84%) brain stems.

CONCLUSIONS

This anatomical study gives important information for a better understanding of the clinical picture of ischemic lesions of the brain stem, such as the medial medullary syndrome, and highlights the remarkable role of the AVSA and ASA as anatomical landmarks during the surgical approaches to lesions involving the ventral aspect of the medulla and the foramen magnum.

Dysphagia after stroke: incidence, diagnosis, and pulmonary complications

OBJECTIVE

To determine the incidence of dysphagia and associated pulmonary compromise in stroke patients through a systematic review of the published literature.

METHODS

Databases were searched (1966 through May 2005) using terms "cerebrovascular disorders," "deglutition disorders," and limited to "humans" for original articles addressing the frequency of dysphagia or pneumonia. Data sources included Medline, Embase, Pascal, relevant Internet addresses, and extensive hand searching of bibliographies of identified articles. Selected articles were reviewed for quality, diagnostic methods, and patient characteristics. Comparisons were made of reported dysphagia and pneumonia frequencies. The relative risks (RRs) of developing pneumonia were calculated in patients with dysphagia and confirmed aspiration.

RESULTS

Of the 277 sources identified, 104 were original, peer-reviewed articles that focused on adult stroke patients with dysphagia. Of these, 24 articles met inclusion criteria and were evaluated. The reported incidence of dysphagia was lowest using cursory screening techniques (37% to 45%), higher using clinical testing (51% to 55%), and highest using instrumental testing (64% to 78%). Dysphagia tends to be lower after hemispheric stroke and remains prominent in the rehabilitation brain stem stroke. There is increased risk for pneumonia in patients with dysphagia (RR, 3.17; 95% CI, 2.07, 4.87) and an even greater risk in patients with aspiration (RR, 11.56; 95% CI, 3.36, 39.77).

CONCLUSIONS

The high incidence for dysphagia and pneumonia is a consistent finding with stroke patients. The pneumonia risk is greatest in stroke patients with aspiration. These findings will be valuable in the design of future dysphagia research.

Lesional location of lateral medullary infarction presenting hiccups (singultus)

BACKGROUND

Hiccups are an infrequent result of lateral medullary infarction. Their importance may be underestimated and they can cause distress, exhaustion, and aspiration. Hiccups in lateral medullary infarction remain poorly understood

OBJECTIVE

To evaluate the relation between the lesional loci of lateral medullary infarction and hiccups.

METHODS

51 patients with lateral medullary infarction were investigated by magnetic resonance imaging within three days of the onset of infarction. Seven of the 51 patients developed hiccup.

RESULTS

All patients with hiccups had middle level lateral medullary lesions, including two with lower level lesions and four with upper level lesions. In the middle level lateral medullary lesions, dorsolateral lesions were most often involved. All patients with lateral medullary infarction presenting with hiccups also had vertigo, dizziness, nausea, vomiting, and dysphagia.

CONCLUSIONS

The observations suggest that middle level and dorsolateral lesion locations in lateral medullary infarction frequently induce hiccups.

Inhalation of tobramycin in a patient with aspiration pneumonia as a result of medullary stroke

A 78-year-old man suffered from refractory aspiration pneumonia as a result of a minor medullary stroke. The only neurological symptom observed in this patient was difficulty in swallowing. He was managed with i.v. hyperalimentation with termination of oral intake, including water. However, he still experienced several episodes of aspiration pneumonia. As he was considered to have a bacterial infection because of silent aspiration of colonized oropharyngeal material, inhalation of tobramycin was introduced and successful control of airway infection was attained.

Predictors and consequences of pneumonia in critically ill patients with stroke

OBJECTIVE

Ascertain the incidence, predictors and consequences of early (within 48 hours of admission) and nosocomial pneumonia among critically ill patients with stroke.

METHODS

Medical records of critically ill patients with acute stroke were reviewed. Predictors and consequences of pneumonia were determined with analysis of variance.

RESULTS

55 patients, aged 33 to 91 (median 74) years, were admitted. The stroke was located at the brainstem in 14 (26.4%) patients. Nine patients (16.4%) had early pneumonia and additional 17 patients (30.9%) developed nosocomial pneumonia. Patients with brain-stem stroke were more likely to develop early pneumonia (p =.04). Nosocomial pneumonia incidence was higher in patients who failed swallowing evaluation (RR = 6.3, 95% CI: 0.9-43.0) and in those who were intubated (58.6% v 0%, p =.00008). Also, nosocomial pneumonia was associated with longer duration of mechanical ventilation and prolonged hospital stay. Nineteen patients (34.5%) died at the hospital. They were more likely to be older (median 77 versus 69 years, p =.03) with higher admission acuity of illness.

CONCLUSION

Pneumonia complicated stroke in 47% of critically ill patients and adversely impacted the duration of mechanical ventilation and overall length of hospital stay. Aggressive preventive measures are needed to reduce pneumonia occurrence in stroke patients.

Neurophysiology of swallowing

Swallowing is a complex motor event that is difficult to investigate in man by neurophysiological experiments. For this reason, the characteristics of the brain stem pathways have been studied in experimental animals. However, the sequential and orderly activation of the swallowing muscles with the monitoring of the laryngeal excursion can be recorded during deglutition. Although influenced by the sensory and cortical inputs, the sequential muscle activation does not alter from the perioral muscles caudally to the cricopharyngeal sphincter muscle. This is one evidence for the existence of the central pattern generator for human swallowing. The brain stem swallowing network includes the nucleus tractus solitarius and nucleus ambiguus with the reticular formation linking synaptically to cranial motoneuron pools bilaterally. Under normal function, the brain stem swallowing network receives descending inputs from the cerebral cortex. The cortex may trigger deglutition and modulate the brain stem sequential activity. The voluntarily initiated pharyngeal swallow involves several cortical and subcortical pathways. The interactions of regions above the brain stem and the brain stem swallowing network is, at present, not fully understood, particularly in humans. Functional neuroimaging methods were recently introduced into the human swallowing research. It has been shown that volitional swallowing is represented in the multiple cortical regions bilaterally but asymmetrically. Cortical organisation of swallowing can be continuously changed by the continual modulatory ascending sensory input with descending motor output.

SIGNIFICANCE

Dysphagia is a severe symptom complex that can be life threatening in a considerable number of patients. Three-fourths of oropharyngeal dysphagia is caused by neurological diseases. Thus, the responsibility of the clinical neurologist and neurophysiologist in the care for the dysphagic patients is twofold. First, we should be more acquainted with the physiology of swallowing and its disorders, in order to care for the dysphagic patients successfully. Second, we need to evaluate the dysphagic problems objectively using practical electromyography methods for the patients' management. Cortical and subcortical functional imaging studies are also important to accumulate more data in order to get more information and in turn to develop new and effective treatment strategies for dysphagic patients.

Rapidly progressive fatal respiratory failure (Ondine’s curse) in the lateral medullary syndrome

A 70-year-old man presented with unilateral lateral medullary infarction, and then died of rapidly progressive respiratory failure within a day. The clinical manifestations were hiccups, hoarseness, dysarthria, nystagmus, left central facial paralysis, paralysis of the left soft palate, dysphagia, decreased superficial sensation over the right face and upper limb, and cerebellar ataxia in the left upper and lower limbs. The arterial blood gas analysis revealed mild hypoventilation. Soon thereafter, an apneic episode occurred during a sleep and advanced to ataxic respiration, and the patient died. Pathologically, there were fresh ischemic infarction localized to the left dorsolateral area of the upper medulla, caused by atherothrombotic occlusion of the left vertebral artery. These foci were in the areas including the medullary reticular formation, the solitary nucleus, the intramedullary fibers of the vagus nerve, and the nucleus ambiguus on the left side. We attributed the fatal acute progressive respiratory impairment in the present case to impairment of the automatic respiratory system (Ondine's curse) rather than the voluntary respiratory system.

Investigation and management of dysphagia

Dysphagia is a common finding in infants and children with neuromuscular disabilities. Dysphagia may be developmental, as in the preterm infant, transient, chronic, or progressive. The evaluation of dysphagia must take into account the age of the patient and typical development of feeding and swallowing for that age. The typical abilities seen in neonatal, early infancy, later infancy and early childhood periods vary in sensorimotor skills and feeding efficiency. In addition to knowing the substrate of expected skills by age, knowledge of the neurophysiology of feeding and swallowing is essential to diagnosis. Each physiologic phase of deglutition: oral, pharyngeal, and esophageal can present with symptoms of dysphagia that can guide investigation. Common symptoms of dysphagia include generalized feeding difficulty such as poor efficiency, food refusal and failure to thrive. Specific symptoms include tongue thrust, choking, cough, and oxygen desaturation. The possibility of dysphagia can be identified through a thorough feeding history. Examination initially includes the infant's muscle tone and posture in the head, neck and body. Anomalies of structures of the head and neck must be identified and examined for their effect on function. Next, examination of oral structures for reflexes, tongue movements, and symmetry will identify neurologic abnormalities. Observation of feeding is essential and will reveal signs of dysphagia. Aspiration in the infant can present without specific signs. Respiratory abnormalities or Gastroesophageal reflux can be identified during history or examination. Investigation of dysphagia most commonly includes videofluoroscopy, endoscopy, and ultrasonography. The management of dysphagia requires an individualized approach and will include neurologic, respiratory, nutritional and possibly gastrointestinal management. Six broad areas are identified that must be considered in the management of dysphagia in infants and children. They include: normalization of posture and positioning, adaptation of foods and feeding equipment, oromotor therapy, feeding therapy, nutritional support and management of associated disorders. A team of professionals will assist the parent and child in achieving pleasant feedings to foster appropriate growth and development.

Swallowing disorders in the elderly

Changes that occur as a natural part of senescence in the complex action of deglutition predispose us to dysphagia and aspiration. As the "baby-boomers" begin to age, the onset of swallowing difficulties will begin to manifest in a greater number of our population. Recent advances in the evaluation of normal and abnormal swallowing make possible more precise anatomical and physiological diagnoses. Coupled with an understanding of swallowing physiology, such detailed evaluation allows greater opportunity to safely manage dysphagia with directed therapy and appropriate surgical intervention. The current study is a discussion of the changes that occur in deglutition with normal aging, contemporary evaluation of swallowing function, and some of the common causes of dysphagia in elderly patients.

Dysphagia in lateral medullary infarction (Wallenberg's syndrome): an acute disconnection syndrome in premotor neurons related to swallowing activity?

BACKGROUND AND PURPOSE

We have investigated the pathophysiological mechanisms of dysphagia in Wallenberg's syndrome (WS) that are due to lateral medullary infarction (LMI).

METHODS

Twenty patients with WS were evaluated by means of clinical and electrophysiological methods that measured the oropharyngeal phase of voluntarily initiated swallowing. For comparison, 22 patients with unilateral hemispheric infarction were investigated during the acute stage of stroke, and 4 patients with unilateral peripheral 9th and 10th cranial nerve palsies were studied. Age-matched 30 healthy control subjects were also included in the study.

RESULTS

It was found that dysphagia was clinically more severe in WS patients than in the patients in the other groups. The pharyngeal phase of swallowing was predominantly impaired, whereas in patients with hemispheric stroke, dysphagia was related only to the delay of triggering of the voluntarily induced swallowing. In WS patients, the swallowing reflex was extremely slow in spite of the unilateral involvement due to LMI, whereas the pharyngeal phase of reflex swallowing remained within normal limits in patients with unilateral hemispheric stroke and patients with unilateral peripheral 9th and 10th cranial nerve palsies.

CONCLUSIONS

Although in WS the lesion due to LMI is unilateral, its effect on oropharyngeal swallowing is bilateral. In LMI, primarily the premotor neurons in the nucleus ambiguous and their connections seem to be affected. Consequently, a disruption and/or disconnection of their linkage to swallowing-related cranial motor neuron pools bilaterally and to the contralateral nucleus ambiguous could produce the swallowing disorders in WS. However, the remaining intact ipsilateral premotor neurons and the contralateral center in the medulla oblongata may eventually begin to operate and overcome the severity and long-term persistence of dysphagia.