Neuroanatomical correlates of tube dependency and impaired oral intake after hemispheric stroke

Development and validation of a risk prediction model for aspiration in patients with acute ischemic stroke

BACKGROUND

Aspiration is a frequently observed complication in individuals diagnosed with acute ischemic stroke, leading to potentially severe consequences. However, the availability of predictive tools for assessing aspiration probabilities remains limited. Hence, our study aimed to develop and validate a nomogram for accurately predicting aspiration probability in patients with acute ischemic stroke.

METHODS

We analyzed 30 potential risk factors associated with aspiration in 359 adult patients diagnosed with acute ischemic stroke. Advanced statistical techniques, such as Least absolute shrinkage and selection operator (LASSO) and Multivariate Logistic regression, were employed to identify independent predictors. Subsequently, we developed a nomogram prediction model based on these predictors, which underwent internal validation through 1000 bootstrap resampling. Two additional cohorts (Cohort A n = 64; Cohort B, n = 105) were included for external validation. The discriminatory power and calibration performance of the nomogram were assessed using rigorous methods, including the Hosmer-Lemeshow test, area under the receiver operating characteristic curve (AUC), calibration curve analyses, and decision curve analyses (DCA).

RESULTS

The nomogram was established based on four variables: sputum suction, brain stem infarction, temporal lobe infarction, and Barthel Index score. The predictive model exhibited satisfactory discriminative ability, with an area under the receiver operating characteristic curve of 0.853 (95 % confidence interval, 0.795-0.910), which remained consistent at 0.852 (95 % confidence interval, 0.794-0.912) during the internal validation. The Hosmer-Lemeshow test (P = 0.394) and calibration curve demonstrated favorable consistency between the predicted and observed outcomes in the development cohort. The AUC was 0.872 (95 % confidence interval, 0.783-0.962) in validation cohort A and 0.877 (95 % confidence interval, 0.764-0.989) in validation cohort B, demonstrating sustained accuracy. DCA showed a good net clinical benefit of the nomogram.

CONCLUSIONS

A nomogram for predicting the probability of aspiration in patients with acute ischemia has been successfully developed and validated.

The Cortical and Subcortical Neural Control of Swallowing: A Narrative Review

Swallowing is a sophisticated process involving the precise and timely coordination of the central and peripheral nervous systems, along with the musculatures of the oral cavity, pharynx, and airway. The role of the infratentorial neural structure, including the swallowing central pattern generator and cranial nerve nuclei, has been described in greater detail compared with both the cortical and subcortical neural structures. Nonetheless, accumulated data from analysis of swallowing performance in patients with different neurological diseases and conditions, along with results from neurophysiological studies of normal swallowing have gradually enhanced understanding of the role of cortical and subcortical neural structures in swallowing, potentially leading to the development of treatment modalities for patients suffering from dysphagia. This review article summarizes findings about the role of both cortical and subcortical neural structures in swallowing based on results from neurophysiological studies and studies of various neurological diseases. In sum, cortical regions are mainly in charge of initiation and coordination of swallowing after receiving afferent information, while subcortical structures including basal ganglia and thalamus are responsible for movement control and regulation during swallowing through the cortico-basal ganglia-thalamo-cortical loop. This article also presents how cortical and subcortical neural structures interact with each other to generate the swallowing response. In addition, we provided the updated evidence about the clinical applications and efficacy of neuromodulation techniques, including both non-invasive brain stimulation and deep brain stimulation on dysphagia.

The neurorehabilitation of post-stroke dysphagia: Physiology and pathophysiology

Swallowing is a complex process involving the precise contractions of numerous muscles of the head and neck, which act to process and shepherd ingested material from the oral cavity to its eventual destination, the stomach. Over the past five decades, information from animal and human studies has laid bare the complex network of neurones in the brainstem, cortex and cerebellum that are responsible for orchestrating each normal swallow. Amidst this complexity, problems can and often do occur that result in dysphagia, defined as impaired or disordered swallowing. Dysphagia is common, arising from multiple varied disease processes that can affect any of the neuromuscular structures involved in swallowing. Post-stroke dysphagia (PSD) remains the most prevalent and most commonly studied form of dysphagia and, as such, provides an important disease model to assess dysphagia physiology and pathophysiology. In this review, we explore the complex neuroanatomical processes that occur during normal swallowing and PSD. This includes how strokes cause dysphagia, the mechanisms through which natural neuroplastic recovery occurs, current treatments for patients with persistent dysphagia and emerging neuromodulatory treatments.

Subacute prognosis of oral nutrition (SPOON): Development of a multivariable prognostic model for complete oral intake in tube-fed subjects with acquired brain injury

BACKGROUND & AIMS

Enteral feeding is very common following an acquired brain injury. However, no prognostic models for oral food intake have been developed for subacute rehabilitation. The aim of this study was to develop a prognostic model and online tool, coined "subacute prognosis of oral nutrition" (SPOON), for complete oral intake in tube-fed subjects with acquired brain injury.

METHODS

The model was developed using routinely gathered clinical data from a cohort of 1233 adult patients who were tube-fed at admission for sub-acute inpatient rehabilitation. Candidate predictors were included based on scientific evidence and their availability in the medical records within the first days following admission. The outcome was time until achieving complete oral food intake without any tube-feeding supplements. Time until complete oral intake was analyzed by discrete time-to-event analysis with logit-link and presented as daily odds ratios (OR) with 95% confidence intervals (CI).

RESULTS

The following predictors of complete oral intake were included in the model: age, diagnosis, cuffed tracheostomy tube, days from injury to admission for rehabilitation, and the Early Functional Abilities (EFA) sum score. Multiple adjusted analyses were performed stratified by cuffed tracheostomy tube status. Some of the strongest predictors of complete oral intake were age 18-40 years, OR 1.99 (95%CI: 1.53; 2.59); 0-2 weeks since injury, OR 3.75 (95%CI: 2.72; 5.16); and EFA 61-100 (slight/no disturbance in function), OR 5.81 (95%CI: 4.47; 7.55). The online prognostic tool SPOON was evaluated in a usability study. Based on feedback from clinicians, the tool was further refined to enable extraction of data for prediction directly from medical records.

CONCLUSIONS

The objective of SPOON is to complement the planning of rehabilitation initiatives and inform discussions to determine if a percutaneous endoscopic gastrostomy (PEG) tube should be inserted. SPOON is being implemented locally, but external validation based on appropriate data modeling is warranted before further clinical implementation.

Characteristics of post-stroke dysphagia: A retrospective study based on FEES

OBJECTIVE

This study aims to examine the characteristics of dysphagia in stroke patients with different lesion sites and explore the factors that impact the duration of nasogastric tube after post-stroke dysphagia (PSD).

METHODS

Patients with PSD were screened for analysis. Stroke types and lesion sites were confirmed using MRI or CT scans. Included patients were categorized into two groups: supratentorial stroke group (including lobar and deep intracerebral stroke subgroups) and infratentorial stroke group (including brainstem and cerebellar stroke subgroups). Fiberoptic endoscopic evaluation of swallowing (FEES), Penetration-aspiration scale (PAS), Yale pharyngeal residue (PR) severity rating scale, Functional oral intake scale (FOIS), Murray secretion severity rating scale (MSS), laryngopharyngeal sensation, and vocal fold mobility were investigated to assess the swallowing function.

RESULTS

A total of 94 patients were included in the final analysis. Significant differences were found in PR scores (p < .001), PAS scores (p < .05), MSS scores (p < .05), and vocal fold mobility (p < .001) between infratentorial and supratentorial stroke groups. Moreover, lobar stroke showed significantly higher PR scores compared to the deep intracerebral stroke group (p < .05). Kaplan-Meier survival analysis indicated significant differences in the duration of nasogastric tube placement among the following groups: infratentorial versus supratentorial stroke, PAS ≤ 5 versus PAS > 5, PR ≥ 3 versus PR < 3, and normal vocal fold mobility versus vocal fold motion impairment group (p < .05).

CONCLUSIONS

The infratentorial stroke may lead to worse swallowing function as compared to a supratentorial stroke. Additionally, patients with infratentorial stroke, PAS > 5, PR ≥ 3, or vocal fold motion impairment may contribute to a longer duration of nasogastric tube placement.

Simultaneous Four Supratentorial Lesions Predict Tube Dependency Due to an Impaired Anticipatory Phase of Ingestion

This study aimed to identify the neuroanatomical predictors of oropharyngeal dysphagia and tube dependency in patients with supratentorial or infratentorial ischemic strokes. Patients with acute ischemic stroke were enrolled and were classified into 3 groups: right supratentorial (n = 61), left supratentorial (n = 89), and infratentorial stroke (n = 50). Dysphagia was evaluated by a modified water swallowing test and the Food Intake LEVEL Scale to evaluate oropharyngeal dysphagia and tube dependency, respectively. As two dysphagia parameters, we evaluated the durations from onset of stroke to (1) success in the modified water swallowing test and to (2) rating 7 points or above on the Food Intake LEVEL Scale: patients regained sufficient oral intake and were not tube-dependent. Voxel-based lesion-symptom mapping analysis was performed for a spatially normalized lesion map of magnetic resonance imaging to explore the anatomies that are associated with the two dysphagia parameters for each stroke group. The right precentral gyrus and parts of the internal capsule are associated with oropharyngeal dysphagia. The four supratentorial areas are associated with tube dependency. The dorsal upper medulla is associated with both oropharyngeal dysphagia and tube dependency. These results suggest that supratentorial stroke patients can be tube-dependent due to an impaired anticipatory phase of ingestion. The simultaneous damage in the four supratentorial areas: the inferior part of the precentral gyrus, lenticular nucleus, caudate head, and anterior insular cortex, predicts tube dependency. In contrast, infratentorial stroke patients can be tube-dependent due to oropharyngeal dysphagia caused by lesions in the dorsal upper medulla, damaging the swallowing-related nucleus.

Neural basis of dysphagia in stroke: A systematic review and meta-analysis

Objectives

Dysphagia is a major cause of stroke infection and death, and identification of structural and functional brain area changes associated with post-stroke dysphagia (PSD) can help in early screening and clinical intervention. Studies on PSD have reported numerous structural lesions and functional abnormalities in brain regions, and a systematic review is lacking. We aimed to integrate several neuroimaging studies to summarize the empirical evidence of neurological changes leading to PSD.

Methods

We conducted a systematic review of studies that used structural neuroimaging and functional neuroimaging approaches to explore structural and functional brain regions associated with swallowing after stroke, with additional evidence using a live activation likelihood estimation (ALE) approach.

Results

A total of 35 studies were included, including 20 studies with structural neuroimaging analysis, 14 studies with functional neuroimaging analysis and one study reporting results for both. The overall results suggest that structural lesions and functional abnormalities in the sensorimotor cortex, insula, cerebellum, cingulate gyrus, thalamus, basal ganglia, and associated white matter connections in individuals with stroke may contribute to dysphagia, and the ALE analysis provides additional evidence for structural lesions in the right lentiform nucleus and right thalamus and functional abnormalities in the left thalamus.

Conclusion

Our findings suggest that PSD is associated with neurological changes in brain regions such as sensorimotor cortex, insula, cerebellum, cingulate gyrus, thalamus, basal ganglia, and associated white matter connections. Adequate understanding of the mechanisms of neural changes in the post-stroke swallowing network may assist in clinical diagnosis and provide ideas for the development of new interventions in clinical practice.

Dysphagia assessment in ischemic stroke after mechanical thrombectomy: When and how?

Background

Dysphagia is a frequent symptom in acute ischemic stroke (AIS). Endovascular treatment (EVT) has become the standard of care for acute stroke secondary to large vessel occlusion. Although standardized guidelines for poststroke dysphagia (PSD) management exist, they do not account for this setting in which patients receive EVT under general anesthesia. Therefore, the aim of this study was to evaluate PSD prevalence and severity, as well as an appropriate time point for the PSD evaluation, in patients undergoing EVT under general anesthesia (GA).

Methods

We prospectively included 54 AIS patients undergoing EVT under GA. Fiberoptic Endoscopic Evaluation of Swallowing (FEES) was performed within 24 h post-extubation in all patients. Patients presenting significant PSD received a second FEES-assessment to determine the course of dysphagia deficits over time. Dysphagia severity was rated according the Fiberoptic Dysphagia Severity Scale (FEDSS).

Results

At first FEES (FEES 1) assessment, performed in the median 13 h (IQR 5-17) post-extubation, 49/54 patients (90.7%) with dysphagia were observed with a median FEDSS of 4 (IQR 3-6). Severe dysphagia requiring tube feeding was identified in 28/54 (51.9%) subjects, whereas in 21 (38.9%) patients early oral diet with certain food restrictions could be initiated. In the follow up FEES examination conducted in the median 72 h (IQR 70-97 h) after initial FEES 34/49 (69.4%) patients still presented PSD. Age (p = 0.030) and ventilation time (p = 0.035) were significantly associated with the presence of PSD at the second FEES evaluation. Significant improvement of dysphagia frequency (p = 0.006) and dysphagia severity (p = 0.001) could be detected between the first and second dysphagia assessment.

Conclusions

PSD is a frequent finding both immediately within 24 h after extubation, as well as in the short-term course. In contrast to common clinical practice, to delay evaluation of swallowing for at least 24 h post-extubation, we recommend a timely assessment of swallowing function after extubation, as 50% of patients were safe to begin oral intake. Given the high amount of severe dysphagic symptoms, we strongly recommend application of instrumental swallowing diagnostics due to its higher sensitivity, when compared to clinical swallowing examination. Furthermore, advanced age, as well as prolonged intubation, were identified as significant predictors for delayed recovery of swallowing function.

The efficacy and safety of catheter balloon dilatation in the treatment of dysphagia after stroke: A protocol for systematic review and meta-analysis

BACKGROUND

Dysphagia is a serious complication after stroke, which has a significant influence on the health as well as life quality of global people. Patients with dysphagia tend to be a higher risk rate of an aspiration than general person. Catheter balloon dilatation is an additional therapy for treating dysphagia in recent years, which can improve the symptom of achalasia of cricopharyngeal muscle. This research will be used for confirming the efficacy and safety of the catheter balloon dilatation for resolving dysphagia.

METHODS

We intend to search literature related to the research in different databases, for instance, China National Knowledge Infrastructure, Wanfang Data, PubMed, Cochrane Library, and Embase up to January 2022. Literature selection, data collection, as well as assessment of bias risk, will be carried out by 2 independent researchers. Data analysis will be conducted by using Stata and review manager 5.4.

RESULTS

The results will be submitted to a peer-reviewed journal.

CONCLUSION

The research will verify whether or not catheter balloon dilatation can improve dysphagia by submitting high-quality data syntheses.

REGISTRATION NUMBER

CRD42022358433.

Effects of Insular Cortex on Post-Stroke Dysphagia: A Systematic Review and Meta Analysis

Objective: To investigate the relationship of lobar and deep brain regions with post-stroke dysphagia (PSD). Method: The databases of Medline, Embase, Web of Science, and Cochrane Library were searched from the establishment to May 2022. Studies that investigated the effects of lesions in lobar and deep brain regions on swallowing function after stroke were screened. The primary outcomes were PSD-related brain regions (including aspiration-related and oral transit time-related brain regions). The secondary outcomes were the incidence rate of PSD. The brain regions with the most overlap in the included studies were considered to be most relevant to PSD, and were presented as percentages. Data were compared utilizing the t-tests for continuous variables and χ2 for frequency-based variables. Result: A total of 24 studies and 2306 patients were included. The PSD-related lobar and deep brain regions included the insular cortex, frontal lobe, temporal gyrus, basal ganglia, postcentral, precentral, precuneus, corona radiate, etc. Among these brain regions, the insular cortex was most frequently reported (taking up 54.2%) in the included studies. Furthermore, the total incidence rate of PSD was around 40.4%, and the incidence of male was nearly 2.57 times as much as that of female (χ2 = 196.17, p < 0.001). Conclusions: In lobar and deep brain regions, the insular cortex may be most relevant to PSD and aspiration, which may be a potentially promising target in the treatment of PSD.

Neurogenic Dysphagia in Subdural Hematoma

Introduction

Dysphagia is a common and severe symptom of traumatic brain injury (TBI) affecting up to 78% of patients. It is associated with pneumonia, increased morbidity, and mortality. Although subdural hematoma (SDH) accounts for over 50% of TBI, the occurrence of dysphagia in this subtype has not been investigated yet.

Methods

All patients with SDH admitted to the author's institution between the years 2007 and 2020 were included in the study. Patients with SDH and clinical suspicion for dysphagia received a clinical swallowing assessment by a speech and language pathologist (SLP). Furthermore, the severity of dysphagia was rated according to swallowing disorder scale. Functional outcome was evaluated by the Glasgow outcome scale (GOS).

Results

Out of 545 patients with SDH, 71 patients had dysphagia (13%). The prevalence of dysphagia was significantly lower in the surgical arm compared to the conservative arm (11.8 vs. 21.8%; OR 0.23; p = 0.02). Independent predictors for dysphagia were GCS <13 at admission (OR 4.17; p < 0.001), cardiovascular disease (OR 2.29; p = 0.002), and pneumonia (OR 2.88; p = 0.002), whereas the operation was a protective factor (OR 0.2; p < 0.001). In a subgroup analysis, right-sided SDH was an additional predictor for dysphagia (OR 2.7; p < 0.001). Overall, patients with dysphagia improved significantly under the SLP treatment from the initial diagnosis to hospital discharge (p < 0.01). However, a subgroup of patients with the most severe grade of dysphagia showed no significant improvement. Patients with dysphagia had significantly worse outcomes (GOS 1–3) compared to those without dysphagia (48.8 vs. 26.4%; p < 0.001).

Conclusion

Dysphagia is a frequent symptom in SDH, and the early identification of dysphagia is crucial regarding the initiation of treatment and functional outcome. Surgery is effective in preventing dysphagia and should be considered in high-risked patients.

The Role of White Matter in the Neural Control of Swallowing: A Systematic Review

Background: Swallowing disorders (dysphagia) can negatively impact quality of life and health. For clinicians and researchers seeking to improve outcomes for patients with dysphagia, understanding the neural control of swallowing is critical. The role of gray matter in swallowing control has been extensively documented, but knowledge is limited regarding the contributions of white matter. Our aim was to identify, evaluate, and summarize the populations, methods, and results of published articles describing the role of white matter in neural control of swallowing.

Methods: We completed a systematic review with a multi-engine search following PRISMA-P 2015 standards. Two authors screened articles and completed blind full-text review and quality assessments using an adapted U.S. National Institute of Health's Quality Assessment. The senior author resolved any disagreements. Qualitative synthesis of evidence was completed.

Results: The search yielded 105 non-duplicate articles, twenty-two of which met inclusion criteria. Twenty were rated as Good (5/22; 23%) or Fair (15/22; 68%) quality. Stroke was the most represented diagnosis (n = 20; 91%). All studies were observational, and half were retrospective cohort design. The majority of studies (13/22; 59%) quantified white matter damage with lesion-based methods, whereas 7/22 (32%) described intrinsic characteristics of white matter using methods like fractional anisotropy. Fifteen studies (68%) used instrumental methods for swallowing evaluations. White matter areas commonly implicated in swallowing control included the pyramidal tract, internal capsule, corona radiata, superior longitudinal fasciculus, external capsule, and corpus callosum. Additional noteworthy themes included: severity of white matter damage is related to dysphagia severity; bilateral white matter lesions appear particularly disruptive to swallowing; and white matter adaptation can facilitate dysphagia recovery. Gaps in the literature included limited sample size and populations, lack of in-depth evaluations, and issues with research design.

Conclusion: Although traditionally understudied, there is sufficient evidence to conclude that white matter is critical in the neural control of swallowing. The reviewed studies indicated that white matter damage can be directly tied to swallowing deficits, and several white matter structures were implicated across studies. Further well-designed interdisciplinary research is needed to understand white matter's role in neural control of normal swallowing and in dysphagia recovery and rehabilitation.

Neuroanatomical correlates of poststroke complex regional pain syndrome: a voxel-based lesion symptom-mapping study

Complex regional pain syndrome (CRPS) is a common poststroke complication. However, the neural substrates associated with CRPS remain unclear. We investigated the neural correlates associated with poststroke CRPS using voxel-based lesion‒symptom mapping (VLSM) analysis. Among 145 patients with ischemic stroke, 35 were diagnosed with CRPS and categorized into the poststroke CRPS group, and the remaining 110 into the control group. We compared the clinical characteristics between the groups. VLSM analysis was performed to identify the brain region associated with the development of poststroke CRPS. The clinical findings suggested that the poststroke CRPS group had lower muscle strength; lower scores on Fugl‒Meyer assessment, Manual Function Test, Mini-Mental Status Examination; and higher incidence of absent somatosensory evoked potentials in the median nerve than the control group. The head of the caudate nucleus, putamen, and white matter complexes in the corona radiata were significantly associated with poststroke CRPS development in ischemic stroke patients. These results facilitate an understanding of poststroke CRPS pathophysiology. Monitoring patients with lesions in these structures may aid the prevention and early treatment of poststroke CRPS.

Association of Lesion Pattern and Dysphagia in Acute Intracerebral Hemorrhage

[Figure: see text].

Ischemic Lesion Location Based on the ASPECT Score for Risk Assessment of Neurogenic Dysphagia

Dysphagia is common in patients with middle cerebral artery (MCA) infarctions and associated with malnutrition, pneumonia, and mortality. Besides bedside screening tools, brain imaging findings may help to timely identify patients with swallowing disorders. We investigated whether the Alberta stroke program early CT score (ASPECTS) allows for the correlation of distinct ischemic lesion patterns with dysphagia. We prospectively examined 113 consecutive patients with acute MCA infarctions. Fiberoptic endoscopic evaluation of swallowing (FEES) was performed within 24 h after admission for validation of dysphagia. Brain imaging (CT or MRI) was rated for ischemic changes according to the ASPECT score. 62 patients (54.9%) had FEES-proven dysphagia. In left hemispheric strokes, the strongest associations between the ASPECTS sectors and dysphagia were found for the lentiform nucleus (odds ratio 0.113 [CI 0.028–0.433; p = 0.001), the insula (0.275 [0.102–0.742]; p = 0.011), and the frontal operculum (0.280 [CI 0.094–0.834]; p = 0.022). A combination of two or even all three of these sectors together increased relative dysphagia frequency up to 100%. For right hemispheric strokes, only non-significant associations were found which were strongest for the insula region. The distribution of early ischemic changes in the MCA territory according to ASPECTS may be used as risk indicator of neurogenic dysphagia in MCA infarction, particularly when the left hemisphere is affected. However, due to the exploratory nature of this research, external validation studies of these findings are warranted in future.

Post-stroke Dysphagia: Recent Insights and Unanswered Questions

PURPOSE OF REVIEW

We explored themes in recent post-stroke dysphagia literature, focusing on the following questions: (1) What does post-stroke dysphagia look like?; (2) Who gets post-stroke dysphagia?; (3) What are the consequences of post-stroke dysphagia?; and (4) How can we improve treatment of post-stroke dysphagia?

RECENT FINDINGS

There have been several improvements in quantitative descriptions of swallowing physiology using standard and new evaluation techniques. These descriptions have been correlated with lesion locations, and several factors can predict development of post-stroke dysphagia and its sequelae. Novel treatment paradigms have leveraged post-stroke neuroplastic improvements using neurostimulation and biofeedback techniques. Despite recent findings, the field is limited by lack of standardization and unanswered questions on rehabilitation variables. Our improved understanding of post-stroke dysphagia will enhance our ability to prevent, identify, and treat it. Future work should be grounded in swallowing physiology and continue refining treatments, particularly in the acute stage.

Cortical and Subcortical Control of Swallowing-Can We Use Information From Lesion Locations to Improve Diagnosis and Treatment for Patients With Stroke?

Purpose Swallowing is a complex process, mediated by a broad bilateral neural network that spans from the brainstem to subcortical and cortical brain structures. Although the cortex's role in swallowing was historically neglected, we now understand, especially through clinical observations and research of patients with stroke, that it substantially contributes to swallowing control. Neuroimaging techniques (e.g., magnetic resonance imaging) have helped significantly to elucidate the role of cortical and subcortical brain areas, in general, and the importance of specific areas in swallowing control in healthy individuals and patients with stroke. We will review recent discoveries in cortical and subcortical neuroimaging research studies and their generalizability across patients to discuss their potential implications and translation to dysphagia diagnosis and treatment in clinical practice. Conclusions Stroke lesion locations have been identified that are commonly associated across patients with the occurrence and recovery of dysphagia, suggesting that clinical brain scans provide useful information for improving the diagnosis and treatment of patients with stroke. However, individual differences in brain structure and function limit the generalizability of these relationships and emphasize that the extent of the motor and sensory pathology in swallowing, and how the patient recovers, also depends on a patient's individual brain constitution. The involvement of the damaged brain tissue in swallowing control before the stroke and the health of the residual, undamaged brain tissue are crucial factors that can differ between individuals.

Role of bilateral corticobulbar tracts in dysphagia after middle cerebral artery stroke

BACKGROUND AND PURPOSE

The corticobulbar tract is a potential neural pathway involved in swallowing. The frontal operculum, insular cortex, corona radiata and internal capsule, which are frequently involved in middle cerebral artery (MCA) strokes, are locations in which lesions cause dysphagia. However, it is unclear whether the locations are linked to the corticobulbar tract or whether corticobulbar tract integrity is associated with dysphagia severity. This study aimed to assess the association between corticobulbar tract integrity and dysphagia severity after MCA stroke.

METHODS

Thirty dysphagic patients after MCA stroke and 27 healthy controls were examined. Diffusion tensor imaging (DTI)-derived parameters of the corticobulbar tract were compared between patient and control groups. Next, patients were divided into mild and moderate-to-severe dysphagia groups, and DTI-derived parameters of the corticobulbar tract were compared between the subgroups. Logistic regression analysis was used to determine the association between corticobulbar tract integrity and dysphagia severity.

RESULTS

The tract volume (TV) of the affected corticobulbar tract was lower in dysphagic patients than in healthy controls (P < 0.001). According to dysphagia severity, TV of the unaffected corticobulbar tract was higher in the mild dysphagia group than in the moderate-to-severe dysphagia group (P = 0.012). TV of the unaffected corticobulbar tract was independently associated with dysphagia severity according to the logistic regression model (adjusted odds ratio 0.817, 95% confidence interval 0.683-0.976).

CONCLUSIONS

The corticobulbar tract was affected after MCA stroke and may be associated with dysphagia. A higher corticobulbar TV in the unaffected hemisphere was indicative of better swallowing function in dysphagic patients after MCA stroke.

Development and Validation of a Prognostic Model of Swallowing Recovery and Enteral Tube Feeding After Ischemic Stroke

Importance

Predicting the duration of poststroke dysphagia is important to guide therapeutic decisions. Guidelines recommend nasogastric tube (NGT) feeding if swallowing impairment persists for 7 days or longer and percutaneous endoscopic gastrostomy (PEG) placement if dysphagia does not recover within 30 days, but, to our knowledge, a systematic prediction method does not exist.

Objective

To develop and validate a prognostic model predicting swallowing recovery and the need for enteral tube feeding.

Design, Setting, and Participants

We enrolled participants with consecutive admissions for acute ischemic stroke and initially severe dysphagia in a prospective single-center derivation (2011-2014) and a multicenter validation (July 2015-March 2018) cohort study in 5 tertiary stroke referral centers in Switzerland.

Exposures

Severely impaired oral intake at admission (Functional Oral Intake Scale score <5).

Main Outcomes and Measures

Recovery of oral intake (primary end point, Functional Oral Intake Scale ≥5) or return to prestroke diet (secondary end point) measured 7 (indication for NGT feeding) and 30 (indication for PEG feeding) days after stroke.

Results

In total, 279 participants (131 women [47.0%]; median age, 77 years [interquartile range, 67-84 years]) were enrolled (153 [54.8%] in the derivation study; 126 [45.2%] in the validation cohort). Overall, 64% (95% CI, 59-71) participants failed to recover functional oral intake within 7 days and 30% (95% CI, 24-37) within 30 days. Prolonged swallowing recovery was independently associated with poor outcomes after stroke. The final prognostic model, the Predictive Swallowing Score, included 5 variables: age, stroke severity on admission, lesion location, initial risk of aspiration, and initial impairment of oral intake. Predictive Swallowing Score prediction estimates ranged from 5% (score, 0) to 96% (score, 10) for a persistent impairment of oral intake on day 7 and from 2% to 62% on day 30. Model performance in the validation cohort showed a discrimination (C statistic) of 0.84 (95% CI, 0.76-0.91; P < .001) for predicting the recovery of oral intake on day 7 and 0.77 (95% CI, 0.67-0.87; P < .001) on day 30, and a discrimination for a return to prestroke diet of 0.94 (day 7; 95% CI, 0.87-1.00; P < .001) and 0.71 (day 30; 95% CI, 0.61-0.82; P < .001). Calibration plots showed high agreement between the predicted and observed outcomes.

Conclusions and Relevance

The Predictive Swallowing Score, available as a smartphone application, is an easily applied prognostic instrument that reliably predicts swallowing recovery. It will support decision making for NGT or PEG insertion after ischemic stroke and is a step toward personalized medicine.

Functional Adaptation of Oromotor Functions and Aging: A Focused Review of the Evidence From Brain Neuroimaging Research

“Practice makes perfect” is a principle widely applied when one is acquiring a new sensorimotor skill to cope with challenges from a new environment. In terms of oral healthcare, the traditional view holds that restoring decayed structures is one of the primary aims of treatment. This assumes that the patient’s oromotor functions would be recovered back to normal levels after the restoration. However, in older patients, such a structural–functional coupling after dental treatment shows a great degree of individual variations. For example, after prosthodontic treatment, some patients would adapt themselves quickly to the new dentures, while others would not. In this Focused Review, I argue that the functional aspects of adaptation—which would be predominantly associated with the brain mechanisms of cognitive processing and motor learning—play a critical role in the individual differences in the adaptive behaviors of oromotor functions. This thesis is critical to geriatric oral healthcare since the variation in the capacity of cognitive processing and motor learning is critically associated with aging. In this review, (a) the association between aging and the brain-stomatognathic axis will be introduced; (b) the brain mechanisms underlying the association between aging, compensatory behavior, and motor learning will be briefly summarized; (c) the neuroimaging evidence that suggests the role of cognitive processing and motor learning in oromotor functions will be summarized, and critically, the brain mechanisms underlying mastication and swallowing in older people will be discussed; and (d) based on the current knowledge, an experimental framework for investigating the association between aging and the functional adaptation of oromotor functions will be proposed. Finally, I will comment on the practical implications of this framework and postulate questions open for future research.

Factors Influencing Oral Intake Improvement and Feeding Tube Dependency in Patients with Poststroke Dysphagia

OBJECTIVE

To assess ischemic stroke patients regarding the relationship between lesion locations, swallowing impairment, medical and demographic factors and (1) oral intake improvement and (2) feeding tube dependency at discharge from their acute hospital stay.

METHODS

We conducted an exploratory, retrospective observational longitudinal cohort study of acute, first-ever, ischemic stroke patients. Patients who had an initial nonoral feeding recommendation from a speech and language pathologist and who underwent a modified barium swallow study within their hospital stay were included. Oral intake status was measured with the Functional Oral Intake Scale (FOIS) as the change in FOIS during the hospital stay and as feeding tube dependency at hospital discharge. Associations were assessed with multiple linear regression modeling controlling for age, comorbidities, and hospital length of stay.

RESULTS

We included 44 stroke patients. At hospital discharge, 93% of patients had oral intake restrictions and 30% were feeding tube dependent. Following multiple linear regression modeling, age, damage to the left superior frontal gyrus, dorsal anterior cingulate gyrus, hypothalamus, and nucleus accumbens were significant predictors for FOIS change. Feeding tube dependency showed no significant associations with any prognostic variables when controlling for confounders.

CONCLUSIONS

The vast majority of patients with an initial nonoral feeding recommendation are discharged with oral intake restrictions indicating a continued need for swallowing assessments and treatment after discharge. Lesion locations associated with motivation, reward, and drive to consume food as well as swallowing impairment, higher age, and more comorbidities were related to less oral intake improvement.

Mapping acute lesion locations to physiological swallow impairments after stroke

Dysphagia is a common deficit after a stroke, and it is frequently associated with pneumonia, malnutrition, dehydration, and poor quality of life. It is not yet fully clear which brain regions are directly related to swallowing, and how lesions affect swallow physiology. This study aimed to assess the statistical relationship between acute stroke lesion locations and impairment of specific aspects of swallow physiology. We performed lesion symptom mapping with 68 retrospectively recruited, acute, first-ever ischemic stroke patients. Lesions were determined on diffusion weighted MRI scans. Post-stroke swallow physiology was determined using the Modified Barium Swallow Study Impairment Profile (MBSImP©™). The relationship between brain lesion location and 17 physiological aspects of swallowing were tested using voxel-based and region-based statistical associations corrected for multiple comparisons using permutation thresholding. We found that laryngeal elevation, anterior hyoid excursion, laryngeal vestibular closure, and pharyngeal residue were associated with lesioned voxels or regions of interests. All components showed distinct and overlapping lesion locations, mostly in the right hemisphere, and including cortical regions (inferior frontal gyrus, pre- and postcentral gyrus, supramarginal gyrus, angular gyrus, superior temporal gyrus, insula), subcortical regions (thalamus, amygdala) and white matter tracts (superior longitudinal fasciculus, corona radiata, internal capsule, external capsule, ansa lenticularis, lenticular fasciculus). Our findings indicate that different aspects of post-stroke swallow physiology are associated with distinct lesion locations, primarily in the right hemisphere, and primarily including sensory-motor integration areas and their corresponding white matter tracts. Future studies are needed to expand on our findings and thus, support the development of a neuroanatomical model of post-stroke swallow physiology and treatment approaches targeting the neurophysiological underpinnings of swallowing post stroke.

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Different aspects of swallow physiology are associated with distinct stroke lesion locations.

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Sensory-motor integration areas and white matter tracts are crucial for swallow physiology.

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Mostly regions in the right and only few in the left hemisphere contribute to swallow physiology.

Diverging lesion and connectivity patterns influence early and late swallowing recovery after hemispheric stroke

Knowledge about the recovery of oral intake after hemispheric stroke is important to guide therapeutic decisions, including the administration of enteral tube feeding and the choice of the appropriate feeding route. They aimed to determine the localization and connectivity of lesions in impaired recovery versus recovered swallowing after initially dysphagic stroke. Sixty-two acute ischemic hemispheric stroke patients with impaired oral intake were included in a prospective observational cohort study. Voxel-based lesion-symptom mapping and probabilistic tractography were used to determine the association of lesion location and connectivity with impaired recovery of oral intake ≥7 days (indication for early tube feeding) and ≥4 weeks (indication for percutaneous endoscopic gastrostomy feeding) after stroke. Two distinct patterns influencing recovery of swallowing were recognized. Firstly, impaired recovery of oral intake after ≥7 days was significantly associated with lesions of the superior corona radiata (65% of statistical map, P < 0.05). The affected fibers were connected with the thalamus, primary motor, and supplemental motor areas and the basal ganglia. Secondly, impaired recovery of oral intake after ≥4 weeks significantly correlated with lesions of the anterior insula (54% of statistical map, P < 0.05), which was connected to adjacent operculo-insular areas of deglutition. These findings indicate that early swallowing recovery is influenced by white matter lesions disrupting thalamic and corticobulbar projection fibers. Late recovery is determined by specific cortical lesions affecting association fibers. This knowledge may help clinicians to identify patients at risk of prolonged swallowing problems that would benefit from enteral tube feeding. Hum Brain Mapp 38:2165-2176, 2017. © 2017 Wiley Periodicals, Inc.