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

Factors associated with oropharyngeal dysphagia and unsuccessful nasogastric tube removal after endovascular thrombectomy for anterior circulation stroke

PURPOSE

To identify the predictive variables for post-stroke dysphagia (PSD) among anterior circulation large vessel occlusion (LVO) stroke patients who underwent endovascular thrombectomy (EVT).

METHODS

This retrospective cohort study enrolled hospitalized patients with anterior LVO stroke who underwent EVT between January 1, 2018 and October 31, 2022. PSD was defined as the unsuccessful removal of the nasogastric (NG) tube. Factors, such as premorbid characteristics, laboratory results, EVT, rehabilitation-related parameters, and neuro-imaging, were analyzed for correlations to PSD at 4 and 12 weeks.

RESULTS

The study enrolled 136 patients, with a mean age of 72.9 ± 13.0 years, and 59 patients (43.4%) were male. At 4 weeks, 47.1% of the patients needed an NG tube, and at 12 weeks, 16.2% still required an NG tube. We found that lower albumin, lower body mass index (BMI), higher initial and 24-h post-EVT National Institute of Health Stroke Scale (NIHSS) scores, stroke-associated pneumonia, poor initial sitting balance and ability to sit up, insula or frontal operculum lesions, and bilateral hemisphere involvement were all associated with PSD at both 4 and 12 weeks in the univariate logistic regression. Multivariate analysis revealed that significant predictors of unsuccessful NG tube removal at 4 weeks included lower BMI (adjusted OR [aOR] 0.73, p = 0.005), hemorrhagic transformation (aOR 4.01, p = 0.0335), higher NIHSS scores at 24 h post-EVT (aOR 1.13, p = 0.0288), poor initial sitting ability (aOR 0.52, p = 0.0231), insular cortex ischemia (aOR 7.26, p = 0.0056), and bilateral hemisphere involvement (aOR 41.19, p < 0.0001). At 12 weeks, lower BMI (aOR 0.78, p = 0.0098), poor initial sitting balance (aOR 0.57, p = 0.0287), insular cortex lesions (aOR 4.83, p = 0.0092), and bilateral hemisphere involvement (aOR 4.07, p = 0.0139) remained significant predictors.

CONCLUSIONS

In patients with anterior LVO following EVT, PSD was associated with lower BMI, higher NIHSS scores, poor initial sitting balance and sitting ability, insular lesions, and bilateral hemisphere involvement.

Cerebral small vessel disease is an independent determinant of dysphagia after acute stroke

BACKGROUND

The high incidence of dysphagia after acute stroke is likely the result of cumulative effects of the stroke and pre-stroke brain health. While cerebral small vessel disease (cSVD) is recognized as a marker of compromised brain health, it's unclear which neuroanatomical pathologies of cSVD impact post-stroke dysphagia. We assessed the relation between cSVD pathologies, i.e., brain atrophy, white matter hyperintensities (WMH), perivascular spaces, as markers for brain integrity at the time of the stroke, and acute post-stroke dysphagia measured with the Modified Barium Swallow Study (MBSS).

METHODS

We conducted a retrospective, observational study of 40 individuals with an acute first-ever ischemic stroke. We segmented T1-weighted images into gray matter, white matter, and cerebrospinal fluid (CSF) to derive brain atrophy estimates. We scored the presence and severity of periventricular and deep WMH using the Fazekas scale and counted perivascular spaces in the basal ganglia following standard guidelines. Swallow impairments were determined with the Modified Barium Swallow Impairment Profile (MBSImP), Penetration-Aspiration Scale, and timing measures (oral (OTT), and pharyngeal transit times (PTT)). We performed regression to assess the relation between cSVD pathologies and swallowing while controlling for the stroke overlap with the right and left corticobulbar tracts, stroke volume, and the number of days between the MRI and MBSS.

RESULTS

Worse brain atrophy and more severe periventricular WMH were related to more severe MBSImP pharyngeal total scores, and worse deep WMH were related to aspiration events. More severe perivascular spaces in the basal ganglia were related to longer OTT and PTT, with a high explanatory value (27.5% and 25.1%, respectively), even when controlling for chronological age.

CONCLUSIONS

Our results suggest that several aspects of pre-stroke brain health impact dysphagia severity after acute stroke independent of the stroke site and size. These findings contribute to our understanding of mechanisms underlying the variability of post-stroke dysphagia and emphasize the importance of brain structural integrity before the stroke. Future larger studies are warranted.

The neural plasticity and efficacy of acupuncture for post-stroke dysphagia: protocol for a randomized controlled trial with fMRI and DTI

BACKGROUND

Dysphagia, a common complication of acute stroke, is associated with increased mortality and morbidity. Acupuncture, a widely used swallowing therapy in China, has been suggested as an effective therapy for treating Post-Stroke Dysphagia (PSD) by recent meta-analyses and guidelines. The use of resting-state functional Magnetic Resonance Imaging (rs-fMRI) and Diffusion Tensor Imaging (DTI) could explore the change of regional spontaneous neural activity, functional relationships between brain regions, and white matter connectivity patterns after acupuncture intervention for PSD. This trial aims to evaluate the efficacy of acupuncture treatment for PSD and explore its central mechanism by neuroimaging.

METHODS/DESIGN

This randomized controlled trial will recruit 40 PSD patients. All patients will be randomized to either the Real Acupuncture (RA) or Sham Acupuncture (SA) group by a ratio of 1:1. All patients will receive immediate acupuncture treatment in the MRI scanning room, followed by four weeks of long-term acupuncture treatment. The primary outcomes are the rs-fMRI and DTI indicators, which will be evaluated after the immediate and long-term acupuncture treatment. The secondary outcomes are the scales that assess the efficacy, including the Functional Oral Intake Scale (FOIS), Water Swallowing Test (WST), Swallowing Quality Of Life Questionnaire (SWAL-QOL), and National Institute of Health Stroke Scale (NIHSS). The modified version of the Massachusetts General Hospital Acupuncture Sensation Scale (M-MASS) and fMRI sensation record table will also be evaluated.

DISCUSSION

This protocol presents the design of a randomized, single-blind trial that will evaluate the efficacy and explore the neural plasticity of acupuncture treatment for PSD. This trial will deepen our insight into the clinical value of acupuncture for PSD and initially probe into the time-dosage-effect mechanism of acupuncture.

TRIAL REGISTRATION NUMBERS

Chinese Clinical Trial Registry ( www.chictr.org.cn ) ChiCTR2300067480. This study was registered on 9th January 2023.

The integrity of thalamo-dorsolateral prefrontal cortex tract: a key factor in residual consciousness in disorders of consciousness patients

Background

The mesocircuit model describes a complex network that includes the prefrontal cortical-striatopallidal-thalamo-cortical loop systems and is involved in the mechanism underlying consciousness in patients with disorders of consciousness (DoC). Inhibitory signals to the thalamus become hyperactive in DoC patients, leading to a loss of consciousness. Reactivating this mesocircuit system is important for recovering consciousness in these patients. We investigated how the residual integrity of the thalamo-dorsolateral prefrontal cortex tract (TDLPFCT) influences consciousness in patients with DoC.

Methods

This retrospective case-control study included three groups: prolonged DoC (n = 20), stroke without DoC (n = 20), and healthy controls (n = 20). Diffusion tensor imaging (DTI) was performed at least 4 weeks after the onset. Thalamo-DLPFC tracts were reconstructed using diffusion tensor tractography, and fractional anisotropy (FA) and tract volume (TV) were measured for each hemisphere. Consciousness was assessed using the revised coma recovery scale (CRS-R) within a week of brain imaging.

Results

Significant differences in DLPFCT TV were observed across all three groups, in both affected and less-affected lobes, with the DoC group showing the greatest reduction. A significant correlation was found between the TV of the less-affected TDLPFCT and CRS-R score.

Conclusion

The integrity of the TDLPFCT, particularly in the less affected hemisphere, is associated with consciousness levels in patients with prolonged DoC. This finding suggests its potential importance in assessing prognosis and further developing therapeutic strategies for patients with DoC.

A comparative study of diffusion kurtosis imaging and diffusion tensor imaging in detecting corticospinal tract impairment in diffuse glioma patients

PURPOSE

This study aimed to investigate the diagnostic performance of diffusion kurtosis imaging (DKI) and diffusion tensor imaging (DTI) in identifying aberrations in the corticospinal tract (CST), whilst elucidating the relationship between abnormalities of CST and patients' motor function.

METHODS

Altogether 21 patients with WHO grade II or grade IV glioma were enrolled and divided into Group 1 and Group 2, according to the presence or absence of preoperative paralysis. DKI and DTI metrics were generated and projected onto the CST. Histograms of the CST along x, y, and z axes were developed based on DKI and DTI metrics, and compared subsequently to determine regions of aberrations on the fibers. The receiver operating characteristic curve was performed to investigate the diagnostic efficacy of DKI and DTI metrics.

RESULTS

In Group 1, a significantly lower fractional anisotropy, radial kurtosis and mean kurtosis, and a higher mean diffusivity were found in the ipsilateral CST as compared to the contralateral CST. Significantly higher relative axial diffusivity, relative radial diffusivity, and relative mean diffusivity (rMD) were found in Group 1, as compared to Group 2. The relative volume of ipsilateral CST abnormalities higher than the maximum value of mean kurtosis combined with rMD exhibited the best diagnostic performance in distinguishing dysfunction of CST with an AUC of 0.93.

CONCLUSION

DKI is sensitive in detecting subtle changes of CST distal from the tumor. The combination of DKI and DTI is feasible for evaluating the impairment of the CST.

An interesting case of crossed syndrome: ipsilateral facial paralysis with contralateral glossoplegia

BACKGROUND

Stroke is rarely accompanied with peripheral facial paralysis and supranuclear palsy of the hypoglossal nerve. Both sides of the motor cortex innervate the hypoglossal nucleus; therefore, unilateral lesions of the upper motor neurons rarely result in contralateral lingual paresis. We report a rare case of crossed syndrome with associated hyperacute peripheral hemifacial paralysis and contralateral lingual paresis after a lower pontine tegmentum ischemic stroke.

CASE PRESENTATION

A 73-year-old man presented with symptoms of hyperacute peripheral hemifacial paralysis. Upon protrusion, the patient's tongue deviated to the contralateral side, without fasciculation or atrophy. Brain imaging showed focal ischemic stroke in the pontine tegmentum. However, lingual hemiparesis and multimodal neuroimaging findings differed.

CONCLUSIONS

We suggest that cortico-hypoglossal fibers pass through the dorsal pontine. This case of crossed syndrome is a rare report of a lower pontine tegmentum ischemic stroke resembling an upper motor neuron lesion of the contralateral hypoglossal nerve.

The assessment of dysphagia after stroke: state of the art and future directions

Dysphagia is a major complication following an acute stroke that affects the majority of patients. Clinically, dysphagia after stroke is associated with increased risk of aspiration pneumonia, malnutrition, mortality, and other adverse functional outcomes. Pathophysiologically, dysphagia after stroke is caused by disruption of an extensive cortical and subcortical swallowing network. The screening of patients for dysphagia after stroke should be provided as soon as possible, starting with simple water-swallowing tests at the bedside or more elaborate multi-consistency protocols. Subsequently, a more detailed examination, ideally with instrumental diagnostics such as flexible endoscopic evaluation of swallowing or video fluoroscopy is indicated in some patients. Emerging diagnostic procedures, technical innovations in assessment tools, and digitalisation will improve diagnostic accuracy in the future. Advances in the diagnosis of dysphagia after stroke will enable management based on individual patterns of dysfunction and predisposing risk factors for complications. Progess in dysphagia rehabilitation are essential to reduce mortality and improve patients' quality of life after a stroke.

Predicting Failure to Recover Swallowing in Patients with Severe Post-stroke Dysphagia: The DIsPHAGIc Score

In post-stroke dysphagia, early identification of patients at highest risk of failing swallowing recovery (SR) would be useful to decide which of them should undergo percutaneous endoscopic gastrostomy. The studies on this subject were numerous but generally based on small statistical samples. In this retrospective study, 1232 patients with ischemic or hemorrhagic stroke (73.7 ± 13.0 years, 51% men) were assessed: 593 non-dysphagic, 351 partially dysphagic and 288 totally dysphagic. Among the latter, 45.1% could not recover oral intake. A score to assess the risk of failing SR was obtained from the group with total dysphagia, and further 210 patients with total post-stroke dysphagia were utilized for validation. A regular progression of stroke severity markers, complications and mortality was observed from non-dysphagic, to partially dysphagic, up to totally dysphagic patients. Among the latter, seven variables were independently associated with failure of SR, and formed the "DIsPHAGIc score": cerebral lesion Diameter ≥ 6 cm (+ 1), left frontal Ischemia (- 1), Partial anterior circulation syndrome (- 1), Hypoxia (+ 1), Antiplatelet drug (+ 1), GCS verbal reaction < 4 (+ 1), Internal capsule ischemia (- 1). The area under the ROC curve was 0.79 (95% CI 0.74-0.85). For total scores ≥ 2 there was a high risk of failing SR, with specificity 76.9%, sensitivity 72.1% and accuracy 74.7%. The application of the DIsPHAGIc score to the validation sample provided almost identical results. The evolution of post-stroke dysphagia towards irreversibility can be predicted by a simple, reproducible and robust scoring system based on 7 variables commonly available during hospitalization.

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.

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.

Diffusion spectrum imaging of patients with middle cerebral artery stenosis

OBJECTIVE

We aimed to detect microstructural changes in the brains of patients with unilateral middle cerebral artery (MCA) stenosis and to assess the integrity of the fiber structure and the small-world networks using diffusion spectrum imaging (DSI).

METHODS

A total of 21 healthy controls and 48 patients with unilateral MCA stenosis underwent 3.0 T MRI examination using DSI technique. Differential tractography, diffusion connectometry, and structural networks were performed by using DSI software. The correlation between the stenosis and quantitative anisotropy (QA) were analyzed using multiple regression models in the correlation tractography.

RESULTS

Differential tractography analysis showed that the left or right MCA stenosis group had decreased fiber connectivity in the brain network compared with the control group. The correlation tractography analysis of the patients with MCA stenosis showed that QA was negatively correlated with stenosis in the bilateral arcuate fasciculus, bilateral corticostriatal and corticothalamic pathway, bilateral corticopontine and corticospinal tract, right superior longitudinal fasciculus, right cingulum, corpus callosum, and left frontal aslant tract. Statistically significant differences were shown between the MCA stenosis groups and control group in graph density, global efficiency, network path length, and rich club coefficient.

CONCLUSION

DSI revealed that stroke-free patients with unilateral MCA stenosis have a disrupted structural network and damaged white matter fibers. Furthermore, the fiber connection disruption is more severe in the ipsilateral hemisphere and less prominent in the contralateral hemisphere in patients with unilateral MCA stenosis. Therefore, microstructural impairment has happened to patients with unilateral MCA stenosis even at a subclinical stage.

Increased cortical-medulla functional connectivity is correlated with swallowing in dysphagia patients with subacute infratentorial stroke

Patients with infratentorial stroke (IS) exhibit more severe dysphagia and a higher risk of aspiration than patients with supratentorial stroke. Nevertheless, a large proportion of patients with IS regain swallowing function within 6 months; however, the neural mechanism for this recovery remains unclear. We aimed to investigate possible neuroplastic changes involved using functional magnetic resonance imaging (fMRI) and their relation to swallowing function. We assessed 21 patients with IS (mean age: 59.9 ± 11.1 years) exhibiting dysphagia in the subacute phase and 21 healthy controls (mean age: 57.1 ± 7.8 years). Patient evaluations were based on the functional oral intake scale (FOIS), videofluoroscopic swallow study (VFSS), and fMRI. Temporal swallowing measures and the penetration-aspiration scale (PAS) were obtained using VFSS. Whole-brain-medulla resting-state functional connectivity (rsFC) was calculated and compared between patients and healthy controls. The rsFCs were also correlated with functional measures within the patient group. In patients with IS, whole-brain-medulla rsFCs were significantly higher in the precuneus, the left and right precentral gyrus, and the right supplementary motor area compared to those in healthy controls (P < 0.001, family-wise error-corrected cluster-level P < 0.05). The rsFCs to the medulla for the left (r = -0.507, P = 0.027) and right side (r = -0.503, P = 0.028) precentral gyrus were negatively correlated with the PAS. The rsFC between the left (r = 0.470, P = 0.042) and right (r = 0.459, P = 0.048) precentral gyrus to the medulla was positively correlated with upper esophageal sphincter opening durations (UOD). In addition, PAS was also correlated with UOD (r = -0.638, P = 0.003) whereas the laryngeal closure duration was correlated with the hyoid bone movement duration (r = 0.550, P = 0.015). Patients with IS exhibited overall modulation of cortical-medulla connectivity during the subacute phase. Patients with higher connectivities showed better swallowing performance. These findings support that there is cortical involvement in swallowing regulation after IS and can aid in determining potential treatment targets for dysphagia.

Neural correlates in the development of and recovery from dysphagia after supratentorial stroke: A prospective tractography study

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Stroke may lead to unilateral or bilateral CBT changes regardless of dysphagia.

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Poor fractional anisotropy of the unaffected sides relates to limited recovery.

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Swallowing recovery may depend on the integrity of the unaffected CBT.

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Bi-hemispheric reorganization of the CBT is associated with swallowing recovery.

Background

Methods

Results

Conclusions

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.