The Relation Between the Presence of Aspiration or Penetration and the Clinical Indicators of Dysphagia in Poststroke Survivors

Bedside Clinical Swallow Test and the Fiberoptic Endoscopic Evaluation of Swallow - Level of Agreement

Introduction

Bedside test are important tool for evaluating aspiration during swallowing. FEES that is functional endoscopic evaluation of swallowing is a gold standard method used in evaluation of dysphagia patients. Through this study we aim to assess the sensitivity and specificity of Bedside Clinical swallow evaluation in comparison with Fiberoptic Endoscopic Evaluation of Swallowing.

Objective

To analyze which physiological examination amongst oro motor labial examination, lingual examination, gag reflex, coughs during or post swallow, change in voice quality and hyo-laryngeal excursion during swallow with semisolid and thin liquid consistency in the Bedside Clinical swallow evaluation is better indicator for presence or absence of aspiration.

Methodology

38 patients with different diagnostic entities were presented& included in the study for the assessment of swallowing difficulties as presence or absence of aspiration and possibility of weaning from nasogastric or Nasojejunal tube between March 2016 to October 2016. They were 32 (86%) males and 6 (14%) females. Aspiration correlates were assessed using bedside test (labial movement, lingual movement, gag reflex, strength of productive cough, hyo-laryngeal excursion, And post swallow changes in the quality of voice). FEES was then performed and sensitivity and specificity was compared.

Result

Bedside test showed 84.62% sensitivity and 100% specificity in comparison to FEES. Gag and voice quality were noted to have significant difference with value of 0.009 and 0.033 respectively.

Conclusion

Bedside tests can be considered as an important, easy, sensitive, and specific for the detection of aspiration. Combination of gag reflex and change of voice as parameters of aspiration compared with FEES showed high sensitivity and specificity.

The Development of an Artificial Intelligence Video Analysis-Based Web Application to Diagnose Oropharyngeal Dysphagia: A Pilot Study

The gold standard test for diagnosing dysphagia is the videofluoroscopic swallowing study (VFSS). However, the accuracy of this test varies depending on the specialist's skill level. We proposed a VFSS-based artificial intelligence (AI) web application to diagnose dysphagia. Video from the VFSS consists of multiframe data that contain approximately 300 images. To label the data, the server separated them into frames during the upload and stored them as a video for analysis. Then, the separated data were loaded into a labeling tool to perform the labeling. The labeled file was downloaded, and an AI model was developed by training with You Only Look Once (YOLOv7). Using a utility called SplitFolders, the entire dataset was divided according to a ratio of training (70%), test (10%), and validation (20%). When a VFSS video file was uploaded to an application equipped with the developed AI model, it was automatically classified and labeled as oral, pharyngeal, or esophageal. The dysphagia of a person was categorized as either penetration or aspiration, and the final analyzed result was displayed to the viewer. The following labeling datasets were created for the AI learning: oral (n = 2355), pharyngeal (n = 2338), esophageal (n = 1480), penetration (n = 1856), and aspiration (n = 1320); the learning results of the YOLO model, which analyzed dysphagia using the dataset, were predicted with accuracies of 0.90, 0.82, 0.79, 0.92, and 0.96, respectively. This is expected to help clinicians more efficiently suggest the proper dietary options for patients with oropharyngeal dysphagia.

The relationship between dysphagia and the localisation of brain lesion in stroke: is the involvement of the pons and medulla important?

OBJECTIVES

The presence of dysphagia in stroke is associated with mortality and morbidity. The aim of this retrospective study is to present the relationship between dysphagia and the demographic characteristics of the patient, and the type and localisation of brain lesion in the acute period in stroke patients with dysphagia.

MATERIALS AND METHODS

The data of 284 patients who had stroke-related dysphagia, had a disease duration 1-3 months, had no history of swallowing dysfunction before the event, and had their brain MRI/CT reports in the hospital were included.

RESULTS

The rate of tube-dependent oral areas was higher in the lesions located in the pons and the medulla than in the lesions located in the MCA cortex, the basal ganglia, and the cerebellum (p ˂ 0.001, p = 0.032 and p = 0.011, respectively) and the percentage of those fed with NG + TPN + PEG was statistically significantly higher (p = 0.002, p = 0.032 and p = 0.011, respectively). History of pneumonia was found to be statistically significantly higher in the lesions located in the pons and the medulla than in the lesions located in the MCA cortex, ACA cortex, PCA cortex, the basal ganglia, periventricular white matter, the thalamus, the cerebellum, and the midbrain (p ˂ 0.001, p = 0.005, p = 0.023, p ˂ 0.001, p = 0.023, p = 0.001, p = 0.011 and p = 0.023, respectively).

CONCLUSION

In conclusion, although lesion localisation in the acute period in patients with dysphagia varied in terms of clinical swallowing evaluation findings, weight loss, pneumonia history, the rate of tube-dependent intake, were shown to be higher in patients who had lesions in the pons and the medulla, which is a finding that should be considered in the clinical follow-up of acute stroke patients with lesions in the pons and the medulla.

Transcranial direct current stimulation for post-stroke dysphagia: a meta-analysis

BACKGROUND

Strokes may cause some swallowing difficulty or associated dysphagia in 25-80% of patients. This phenomenon has been linked to increased morbidity and mortality. Therefore, the aim of this study was to evaluate the efficacy of transcranial direct current stimulation in patients with dysphagia in post-stroke patients.

METHODS

A systematic search in PubMed, Scopus, Web of Science and MEDLINE was conducted. The articles must have to evaluate an intervention that included transcranial direct current stimulation; the sample had to consist exclusively of patients with post-stroke dysphagia; and the experimental design consisted of randomized controlled trial. Difference in mean differences and their 95% confidence interval were calculated as the between-group difference in means divided by the pooled standard deviation. The I2 statistic was used to determine the degree of heterogeneity.

RESULTS

Of the 9 investigations analyzed, all applied transcranial direct current stimulation in combination with conventional dysphagia therapy to the experimental group. All the studies analyzed identified improvements in swallowing function and meta-analysis confirmed their strong effect on reducing the risk of penetration and aspiration (Hedges's g = 0.55). The results showed that participants who received transcranial direct current stimulation significantly improved swallowing function.

CONCLUSIONS

Transcranial direct current stimulation has positive effects in the treatment of poststroke dysphagia by improving swallowing function, oral and pharyngeal phase times and the risk of penetration and aspiration. Furthermore, its combination with conventional dysphagia therapy, balloon dilatation with catheter or training of the swallowing muscles ensures improvement of swallowing function. PROSPERO registration ID CRD42022314949.

Non-Contact Assessment of Swallowing Dysfunction Using Smartphone Captured Skin Displacements

Early and accurate dysphagia diagnosis is essential for reducing the risk of associated co-morbidities and mortalities. Barriers to current evaluation methods may alter the effectiveness of identifying at-risk patients. This preliminary study evaluates the feasibility of using iPhone X-captured videos of swallowing as a non-contact dysphagia screening tool. Video recordings of the anterior and lateral necks were captured simultaneously with videofluoroscopy in dysphagic patients. Videos were analyzed using an image registration algorithm (phase-based Savitzky-Golay gradient correlation (P-SG-GC)) to determine skin displacements over hyolaryngeal regions. Biomechanical swallowing parameters of hyolaryngeal displacement and velocity were also measured. Swallowing safety and efficiency were assessed by the Penetration Aspiration Scale (PAS), Residue Severity Ratings (RSR), and the Normalized Residue Ratio Scale (NRRS). Anterior hyoid excursion and horizontal skin displacements were strongly correlated with swallows of a 20 mL bolus (r_s = 0.67). Skin displacements of the neck were moderately to very strongly correlated with scores on the PAS (r_s = 0.80), NRRS (r_s = 0.41-0.62), and RSR (r_s = 0.33). This is the first study to utilize smartphone technology and image registration methods to produce skin displacements indicating post-swallow residual and penetration-aspiration. Enhancing screening methods provides a greater chance of detecting dysphagia, reducing the risk of negative health impacts.

Effect of Oral Apraxia on Dysphagia in Patients with Subacute Stroke

Aim of this study was to investigate the effect of post-stroke oral apraxia on dysphagia in patients with subacute stroke. We retrospectively analyzed the clinical data of 130 supratentorial stroke patients from January 2015 to February 2021 who underwent a formal limb and oral apraxia test and videofluoroscopic swallowing study (VFSS), and we compared the patients in two groups: the apraxia and non-apraxia (oral apraxia score > 45 and ≤ 45 points, respectively). All the patients participated in the standardized testing battery. The test variables were videofluoroscopic dysphagia scale (VDS), oral transit time (OTT), pharyngeal delay time (PDT), pharyngeal transit time, and penetration-aspiration scale (PAS); we conducted multivariable regression analysis with those parameters to confirm the significance of oral apraxia as a clinical determinant of post-stroke dysphagia. The mean oral apraxia scores were 38.4 and 47.6 points in the apraxia and non-apraxia groups, respectively (p < 0.001). The apraxia group had a higher proportion of delayed OTT for the 2-mL-thick liquid than the non-apraxia group (17.6% and 4.2%, respectively; p = 0.011). Oral apraxia was a significant determinant of VDS (p < 0.001), delayed OTT of 2-mL-thick liquids (p = 0.028), delayed PDT of cup drinking for thin liquid (p = 0.044), and PAS scores (p = 0.003). The presence of oral apraxia was significantly associated with dysphagia, especially with the VFSS parameters of the oral phase (thick liquid), pharyngeal phase (cup drinking for thin liquid) of swallowing, and increased risk of aspiration in subacute stroke patients. Thus, a formal assessment of oral apraxia is needed for stroke patients with dysphagia.

Expert-level aspiration and penetration detection during flexible endoscopic evaluation of swallowing with artificial intelligence-assisted diagnosis

Flexible endoscopic evaluation of swallowing (FEES) is considered the gold standard in diagnosing oropharyngeal dysphagia. Recent advances in deep learning have led to a resurgence of artificial intelligence-assisted computer-aided diagnosis (AI-assisted CAD) for a variety of applications. AI-assisted CAD would be a remarkable benefit in providing medical services to populations with inadequate access to dysphagia experts, especially in aging societies. This paper presents an AI-assisted CAD named FEES-CAD for aspiration and penetration detection on video recording during FEES. FEES-CAD segments the input FEES video and classifies penetration, aspiration, residue in the vallecula, and residue in the hypopharynx based on the segmented FEES video. We collected and annotated FEES videos from 199 patients to train the network and tested the performance of FEES-CAD using FEES videos from other 40 patients. These patients consecutively underwent FEES between December 2016 and August 2019 at Fukushima Medical University Hospital. FEES videos were deidentified, randomized, and rated by FEES-CAD and laryngologists with over 15 years of experience in performing FEES. FEES-CAD achieved an average Dice similarity coefficient of 98.6[Formula: see text]. FEES-CAD achieved expert-level accuracy performance on penetration (92.5[Formula: see text]), aspiration (92.5[Formula: see text]), residue in the vallecula (100[Formula: see text]), and residue in the hypopharynx (87.5[Formula: see text]) classification tasks. To the best of our knowledge, FEES-CAD is the first CNN-based system that achieves expert-level performance in detecting aspiration and penetration.

THE DYSPHAGIA INVESTIGATION: IS THERE STILL SPACE FOR THE VIDEOFLUOROSCOPIC METHOD?

Dysphagia can lead to aspiration pneumonia, impacting the nutritional status and quality of life of the patient. The videofluoroscopy is highlighted for allowing both a real-time evaluation and the recording of the images for later review and analysis.

Automatic Pharyngeal Phase Recognition in Untrimmed Videofluoroscopic Swallowing Study Using Transfer Learning with Deep Convolutional Neural Networks

Background: Video fluoroscopic swallowing study (VFSS) is considered as the gold standard diagnostic tool for evaluating dysphagia. However, it is time consuming and labor intensive for the clinician to manually search the recorded long video image frame by frame to identify the instantaneous swallowing abnormality in VFSS images. Therefore, this study aims to present a deep leaning-based approach using transfer learning with a convolutional neural network (CNN) that automatically annotates pharyngeal phase frames in untrimmed VFSS videos such that frames need not be searched manually. Methods: To determine whether the image frame in the VFSS video is in the pharyngeal phase, a single-frame baseline architecture based the deep CNN framework is used and a transfer learning technique with fine-tuning is applied. Results: Compared with all experimental CNN models, that fine-tuned with two blocks of the VGG-16 (VGG16-FT5) model achieved the highest performance in terms of recognizing the frame of pharyngeal phase, that is, the accuracy of 93.20 (±1.25)%, sensitivity of 84.57 (±5.19)%, specificity of 94.36 (±1.21)%, AUC of 0.8947 (±0.0269) and Kappa of 0.7093 (±0.0488). Conclusions: Using appropriate and fine-tuning techniques and explainable deep learning techniques such as grad CAM, this study shows that the proposed single-frame-baseline-architecture-based deep CNN framework can yield high performances in the full automation of VFSS video analysis.

Patients with Head-and-Neck Cancer: Dysphagia and Affective Symptoms

OBJECTIVE

Affective symptoms are common in patients with head-and-neck cancer. This study determined the association between the presence of aspiration and symptoms of anxiety and depression, as well as patient characteristics in patients with head-and-neck cancer and dysphagia.

METHODS

Eighty-four patients with head-and-neck cancer and dysphagia completed the Hospital Anxiety and Depression Scale and underwent a standardized fiberoptic endoscopic evaluation of swallowing. Linear regression analysis was performed to explore the associations.

RESULTS

Fifty-two (61.9%) patients presented clinically relevant symptoms of anxiety or depression. Forty-eight (57.1%) patients presented with aspiration during fiberoptic endoscopic evaluation of swallowing. A significant negative association was found between the presence of aspiration and affective (anxiety and depression) symptoms (p = 0.04). Male patients presented significantly lower symptom scores of anxiety compared to females (p = 0.04).

CONCLUSIONS

Clinically relevant affective symptoms were present in more than half of all patients with head-and-neck cancer and dysphagia. Surprisingly, a significant negative association was found between the presence of aspiration and these affective symptoms. Gender was also significantly associated with affective symptoms. These results suggest that there is a need for further investigation into the impact of psychological distress on patients with head-and-neck cancer and dysphagia.

The effect of reclining position on swallowing function in stroke patients with dysphagia

BACKGROUND

Dysphagia is a common problem in patients with a history of stroke. In Japan, a reclined position is commonly used as a compensatory technique to address this problem.

OBJECTIVE

To evaluate the effect of reclined position on swallowing function in patients with stroke who had dysphagia.

METHODS

A retrospective analysis was carried out on the videofluoroscopic examination of swallowing (VF) of 4ml honey-thick liquid swallows collected over 9 years. Penetration-aspiration scale (PAS) and residue scores were compared for the following: a body position at 90° upright (90°U) and 60° reclining (60°R) groups, as well as 60°R and 45° reclining (45°R) groups.

RESULTS

Two hundred and five records from 98 subjects were reviewed. These included patients with ischaemic stroke (62%), haemorrhagic stroke (32%) and subarachnoid haemorrhage (6%). PAS scores were lower when the body was in a more reclined position (P < .001). The amount of residue in the valleculae and pyriform sinus also reduced in the more reclined position (P < .001). The deeper bolus head at swallowing onset was positively correlated with severe PAS (P < .001).

CONCLUSIONS

These findings suggest that in patients with stroke who had dysphagia, a reclined position may be useful in reducing the risk of penetration and aspiration, and in decreasing the amount of residue in the pharyngeal area. The depth of the bolus head at the onset of swallowing increases the severity of penetration and aspiration.

Biomechanical Biomarkers of Tongue Impairment During Swallowing in Persons Diagnosed with Amyotrophic Lateral Sclerosis

BACKGROUND

The impact of tongue dysfunction on deglutition in persons diagnosed with amyotrophic lateral sclerosis (ALS) is not well understood. This information is needed to improve our understanding of the mechanisms of swallowing impairment, for identifying risk factors of dysphagia, and for establishing impairment-specific treatments aimed at slowing the loss of swallow function.

OBJECTIVES

The goals of this study were to determine the relation between biomechanical measures of oral tongue movements using electromagnetic articulography (EMA) and measures of swallow physiology, swallow safety and efficiency, and self-reported swallowing function.

METHODS

Participants were diagnosed with ALS by a neurologist following the El Escorial Criteria from the World Federation of Neurology. Twelve participants underwent (1) EMA to derive biomechanical measures of the tongue, (2) videofluoroscopic evaluation to measure swallow physiology, safety, and efficiency, and (3) maximal tongue strength testing using the Iowa Oral Pressure Instrument (IOPI). Participants completed self-reported functional assessments. Spearman's rank correlations assessed for associations between lingual biomechanics and swallowing physiology, swallow safety and efficiency, and self-reported bulbar function.

RESULTS

Results demonstrated strong associations between biomechanical and swallowing physiology, swallow safety, and self-reported measures. Notably, swallowing safety during thin liquid intake was associated with tongue speed (r = - 0.7, p < 0.05) and range of motion (r = - 0.71, p < 0.05), and swallowing safety during puree intake was associated with tongue strength (r = - 0.69, p < 0.05).

CONCLUSIONS

Our findings underscore the importance of tongue movements on swallowing physiology and safety, help improve our understanding of mechanisms of swallowing impairment, and highlight a potential clinical tool to index bulbar impairment.

The effectivity of pharyngeal strengthening exercise, hyolaryngeal complex range of motion exercise, and swallowing practice in swallowing function of ischemic stroke patients with neurogenic dysphagia

Dysphagia is associated with an increased risk of aspiration pneumonia which often results in death in stroke patients. Therefore, effective and efficient management is important. Behavioral therapy for swallowing rehabilitation based on the principles of neuroplasticity such as oropharyngeal strengthening and range of motion exercises are the alternative ones that often be used. This study aimed to assess the changes in swallowing function in ischemic stroke patients with neurogenic dysphagia after pharyngeal strengthening exercise, hyolaryngeal complex range of motion exercise and swallowing practice. Swallowing function was assessed using Penetration Aspiration Scale (PAS) and Functional Oral Intake Scale (FOIS) based on Flexible Endoscopic Evaluation of Swallowing before and after interventions. The interventions were given every day with a duration of 30–45 minutes for 4 weeks. There were six subjects who completed the study. The PAS before the interventions were 6.00±1.79 and after the interventions was 1.67±0.82 (P=0.003). Meanwhile, the FOIS score before the interventions was 3 (1–5) and after the interventions were 5.00±2.10 (P=0.041). There was an improvement of PAS and FOIS after the interventions. Therefore, the interventions can be suggested to be used as one of the treatments to improve swallowing function in ischemic stroke patients with neurogenic dysphagia.

Association of Brain Lesions and Videofluoroscopic Dysphagia Scale Parameters on Patients With Acute Cerebral Infarctions

Objective

To investigate the characteristics and risk factors of dysphagia using the videofluoroscopic dysphagia scale (VDS) with a videofluoroscopic swallowing study (VFSS) in patients with acute cerebral infarctions.

Methods

In this retrospective study, the baseline VFSS in 275 stroke patients was analyzed. We divided patients into 8 groups according to lesion areas commonly observed on brain magnetic resonance imaging. Dysphagia characteristics and severity were evaluated using the VDS. We also analyzed the relationship between clinical and functional parameters based on medical records and VDS scores.

Results

In comparison studies of lesions associated with swallowing dysfunction, several groups with significant differences were identified. Apraxia was more closely associated with cortical middle cerebral artery territory lesions. Vallecular and pyriform sinus residue was more common with lesions in the medulla or pons. In addition, the results for the Korean version of the Modified Barthel Index (K-MBI), a functional assessment tool, corresponded to those in the quantitative evaluation of swallowing dysfunctions.

Conclusion

A large cohort of patients with cerebral infarction was evaluated to determine the association between brain lesions and swallowing dysfunction. The results can be used to establish a specific treatment plan. In addition, the characteristic factors associated with swallowing dysfunctions were also confirmed.

Alterations in hyolaryngeal elevation after esophageal anastomosis: A possible mechanism for airway aspiration

AIM

A prospective study was performed to evaluate anatomical alterations and hyolaryngeal elevation (HE) by videofluoroscopic swallowing study (VFSS) in patients with esophageal atresia-tracheoesophageal fistula (EA-TEF).

METHODS

Patients operated for EA-TEF were evaluated for age, sex, type of atresia and time to esophageal anastomosis. All patients were evaluated by videofluoroscopic swallowing study (VFSS). Penetration-Aspiration scale (PAS≥7 is considered as aspiration), distance between upper esophageal sphincter and 2nd cervical vertebrae (UES-C2) and hyolaryngeal elevation (HE) were evaluated by the same deglutitionist who was blind to the study. The results of EA-TEF patients were compared with healthy children.

RESULTS

Eighteen patients with EA-TEF and 10 healthy controls were included. The median age was 16months (12-36m) in EA-TEF and 18months (13-51m) in controls. Male-to-female ratio was 5:4 and 4:1 respectively. 12 of cases were isolated-EA, 1 of them was EA-proximal TEF and 5 of the cases were EA-distal TEF. Half of the cases had primary EAN and others underwent delayed esophageal repair. Early oral feeding was also started in 9 patients (50%) whereas others had delayed oral feeding. VFSS showed aspiration in 27.7 (n=5) of cases (PAS≥7) in EA group. The median distance between UES-C2 was 3.04cm (min: 2.17-max: 3.94) in EA and 4.17cm (min: 3.45-max: 6.24cm) in controls. Median distance for HE was 0.37cm (min: 0.18-max: 1.1cm) in EA and 1.15 (min: 0.61-max: 1.06cm) in controls. The distance between UES-C2 was significantly lower than controls (p<0.05) and HE was decreased in EA-TEF without any statistical significance.

CONCLUSION

Children with EA-TEF had shortened distance between airway and upper esophagus. HE may be inefficient to protect airway during deglutition. Anatomical alterations after EAN suggest that airway problems may be related with decreased HE in children with EATEF.

LEVEL OF EVIDENCE

Level II (Development of diagnostic criteria in a consecutive series of patients and a universally applied "gold standard").

Pharyngeal Swallowing Mechanics Secondary to Hemispheric Stroke

BACKGROUND

Computational analysis of swallowing mechanics (CASM) is a method that utilizes multivariate shape change analysis to uncover covariant elements of pharyngeal swallowing mechanics associated with impairment using videofluoroscopic swallowing studies. The goals of this preliminary study were to (1) characterize swallowing mechanics underlying stroke-related dysphagia, (2) decipher the impact of left and right hemispheric strokes on pharyngeal swallowing mechanics, and (3) determine pharyngeal swallowing mechanics associated with penetration-aspiration status.

METHODS

Videofluoroscopic swallowing studies of 18 dysphagic patients with hemispheric infarcts and age- and gender-matched controls were selected from well-controlled data sets. Patient data including laterality and penetration-aspiration status were collected. Coordinates mapping muscle group action during swallowing were collected from videos. Multivariate morphometric analyses of coordinates associated with stroke, affected hemisphere, and penetration-aspiration status were performed.

RESULTS

Pharyngeal swallowing mechanics differed significantly in the following comparisons: stroke versus controls (D = 2.19, P < .0001), right hemispheric stroke versus controls (D = 3.64, P < .0001), left hemispheric stroke versus controls (D = 2.06, P < .0001), right hemispheric stroke versus left hemispheric stroke (D = 2.89, P < .0001), and penetration-aspiration versus within normal limits (D = 2.25, P < .0001). Differences in pharyngeal swallowing mechanics associated with each comparison were visualized using eigenvectors.

CONCLUSIONS

Whereas current literature focuses on timing changes in stroke-related dysphagia, these data suggest that mechanical changes are also functionally important. Pharyngeal swallowing mechanics differed by the affected hemisphere and the penetration-aspiration status. CASM can be used to identify patient-specific swallowing impairment associated with stroke injury that could help guide rehabilitation strategies to improve swallowing outcomes.

Lesion Characteristics of Chronic Dysphagia in Patients With Supratentorial Stroke

Objective

To analyze the relationship between brain lesion location and type of chronic dysphagia in patients with supratentorial stroke.

Methods

Data from 82 chronic stroke patients who underwent videofluoroscopic swallowing studies at >6 months after an initial stroke event were retrospectively analyzed. Delayed oral transit time, delayed pharyngeal transit time, and the presence of aspiration were extracted. A voxel-based lesion symptom mapping (VLSM) analysis was used to correlate types of dysphagia with specific brain lesions.

Results

VLSM identified several clusters of voxels that significantly correlated with type of dysphagia. Delayed oral transit time mainly correlated with lesions in the left inferior frontal lobe and precentral gyrus; delayed pharyngeal time mainly correlated with lesions in the right basal ganglia and corona radiate; and aspiration was mainly correlated with lesions in the putamen.

Conclusion

Understanding the association between lesion location and dysphagia in chronic stroke patients is an important first step towards predicting permanent dysphagia after stroke. Improved understanding of the neural correlates of dysphagia will inform the utility of interventions for its treatment and prevention after stroke.