Targeting the sensory feedback within the swallowing network-Reversing artificially induced pharyngolaryngeal hypesthesia by central and peripheral stimulation strategies

Cognitive decline limits compensatory resource allocation within the aged swallowing network

Cognitive decline has been postulated to predispose to presbyphagia but the neurophysiological basis of this interaction is unclear. To investigate the role of cognition for compensatory resource allocation within the swallowing network and behavioral swallowing performance in dual-task cognitive and motor interference in ageing, volunteers ≥ 70 years of age without preexisting diseases causing dysphagia were investigated using Flexible Endoscopic Evaluation of Swallowing (FEES) including a cognitive and motor dual-task paradigm and a Montreal Cognitive Assessment. The neural correlates of swallowing during dual-task were characterized using magnetoencephalography. Results were related to cognitive function. Sixty-three participants (77.7 ± 6.1 years) underwent FEES, of which 40 additionally underwent MEG. Both cognitive and motor dual-tasks interfered with swallowing function resulting in an increase in pharyngeal residue and premature bolus spillage. The extent of swallowing deterioration ("dual-task cost") was associated with cognitive decline (cognitive dual-task: Spearman's rho =  - 0.39, p = 0.002; motor dual-task: Spearman's rho =  - 0.25, p = 0.046). When challenged with dual-tasking participants with regular cognition showed compensatory stronger and broader brain activation in cortical pre- and supplementary motor planning areas as well as in frontal executive regions within the cortical swallowing network (p = 0.004) compared to participants with cognitive deficits. They also performed better in the competing cognitive and motor dual-task and showed fewer incorrect responses (p = 0.028). Oropharyngeal swallowing involves cognitive cortical processing. Cognitive decline seems to limit the capacity for compensatory resource allocation within the swallowing network. This may lead to deterioration in both swallowing function and concurrent cognitive-motor performance in challenging dual-task situations.

Clinical predictors of outcome after pharyngeal electrical stimulation (PES) in non-stroke related neurogenic dysphagia after mechanical ventilation and tracheotomy: results from subgroup analysis of PHADER study

BACKGROUND

Pharyngeal electrical stimulation (PES) is a neurostimulation intervention that can improve swallowing and facilitate decannulation in tracheotomised stroke patients with dysphagia. The PHAryngeal electrical stimulation for treatment of neurogenic Dysphagia European Registry (PHADER) study found that PES can reduce dysphagia severity in patients with neurogenic (non-stroke) dysphagia who required mechanical ventilation and tracheotomy. However, the predictive factors for treatment success among these patients remain unclear.

METHODS

We conducted a subgroup analysis using data from PHADER, with a focus on non-stroke participants who had required mechanical ventilation and tracheotomy. Multiple linear regression was performed to predict treatment success, as measured in improvement in dysphagia severity rating scale (DSRS) total score, accounting for age, sex, time from diagnosis to PES, PES perceptual threshold and PES stimulation intensity at the first session.

RESULTS

Fifty-seven participants (mean[standard deviation] age: 63.6[15.5] years; male: 70.2%) were included in the analysis. These comprised traumatic brain injury (22[38.6%]), critical illness polyneuropathy (15[26.4%]), and other neurological conditions that caused dysphagia (20[35.0%]). Regression analyses identified that a lower PES perceptual threshold at the first session (p = 0.027) and early intervention (p = 0.004) were significant predictors associated with treatment success at Day 9 and 3 months post PES respectively.

CONCLUSIONS

We identified two predictive factors associated with successful PES treatment in patients with neurogenic (non-stroke) dysphagia requiring mechanical ventilation and tracheotomy: a lower PES perceptual threshold at the first session and early intervention. These predictors provide critical guidance for optimizing clinical decision-making in managing non-stroke neurogenic dysphagia patients in critical care settings.

Decannulation ahead: a comprehensive diagnostic and therapeutic framework for tracheotomized neurological patients

BACKGROUND

Decannulation in tracheotomized neurological patients is often complicated by severe dysphagia, which compromises airway safety and delays weaning. Additional challenges, including reduced cough strength, excessive bronchial secretions, and altered airway anatomy exacerbate weaning issues, thereby increasing morbidity and mortality. This review summarizes diagnostic procedures and therapeutic options crucial for the rehabilitation of tracheotomized patients.

MAIN BODY

Key diagnostic strategies for assessing decannulation readiness focus on airway protection, airway patency, bronchial secretion management, and cough function. These are collectively introduced as the A2BC criteria in this review. Advanced tools such as flexible endoscopic evaluation of swallowing, endoscopic assessment of airway anatomy, measurement of cough strength, and intrathoracic pressure are essential components of a systematic evaluation. Therapeutic interventions encompass restoring physiological airflow, behavioral swallowing treatment, secretion management, and pharyngeal electrical stimulation. The proposed decannulation algorithm integrates two pathways: the "fast-track" pathway, which facilitates rapid decannulation based on relevant predictors of decannulation-success, and the "standard-track" pathway, which progressively increases cuff deflation intervals to build tolerance over time.

CONCLUSION

Successful decannulation in neurological patients demands a multidisciplinary, patient-centered approach that combines advanced diagnostics, targeted therapies, and structured management pathways. The proposed algorithm integrates fast-track and standard-track pathways, balancing rapid diagnostics with gradual weaning strategies. This framework promotes flexibility, enabling clinicians to tailor interventions to individual patient needs while maintaining safety and optimizing outcomes.

Predictors of pharyngeal electrical stimulation treatment success in tracheotomised stroke patients with dysphagia: Secondary analysis from PHADER cohort study

Pharyngeal electrical stimulation (PES) has emerged as a promising intervention for neurogenic dysphagia, with potential benefits in reducing dysphagia severity in stroke patients. PES may facilitate decannulation in tracheotomised stroke patients with dysphagia, yet the predictive factors for treatment success have not been investigated in detail. This study used data from the PHAryngeal electrical stimulation for treatment of neurogenic Dysphagia European Registry (PHADER) study to identify predictive factors for PES treatment success among patients with post stroke dysphagia who required mechanical ventilation and tracheotomy. Multiple linear regression was performed to predict treatment success, as measured in improvement in dysphagia severity rating scale (DSRS), accounting for age, sex, stroke type, lesion location, baseline National Institutes of Health Stroke Scale (NIHSS) score, feeding status, time from stroke onset to PES, PES perceptual threshold and PES stimulation intensity at the first session. Cox regression was conducted to identify the predictors for decannulation for all participants. Ninety-eight participants (mean [SD] age ​= ​66.6 [13.0]; male 73.5%) were included in the analyses. Regression analyses showed that early intervention (p ​= ​0.004) and younger age (p ​= ​0.049) were significant predictors for treatment success. For participants who received PES during tracheotomy (n ​= ​60; mean [SD] age ​= ​66.6 [11.2]; male 73.3%), supratentorial stroke (p ​= ​0.033) and feeding status at baseline (p ​= ​0.025) were predictors of treatment success. Among all participants, early intervention was associated with higher likelihood of decannulation (p ​= ​0.026). These results highlight the importance of timely intervention, age and stroke location in PES treatment success for stroke patients with mechanical ventilation and tracheotomy.

Pharyngeal Electrical Stimulation prior to extubation - Reduction of extubation failure rate in acute stroke patients?

PURPOSE

The aim of our study was to assess if PES before extubation can minimize the extubation failure risk in orally intubated, mechanically ventilated stroke patients at high risk of severe dysphagia.

MATERIALS AND METHODS

Thirty-two ICU patients were prospectively enrolled in this study presenting with a high risk for dysphagia as defined by a DEFISS (Determine Extubation Failure In Severe Stroke) risk score and compared 1:1 to a retrospective matched patient control group. The prospective patient group received PES prior to extubation. Endpoints were need for reintubation, swallowing function as assessed with FEES, pneumonia incidence and length of stay after extubation.

RESULTS

Post-extubation, the Fiberoptic Endoscopic Dysphagia Severity Score (FEDSS, 4.31 ± 1.53vs.5.03 ± 1.28;p = 0.047) and reintubation rate within 72 h (9.4vs.34.4%;p = 0.032) were significantly lower in the PES group than in the historical control group. Pulmonary infections after extubation were less common in PES-treated patients although this difference was not significant (37.5vs.59.4%;p = 0.133). Time from extubation to discharge was significantly shorter after PES compared with the control group (14.09 ± 11.58vs.26.59 ± 20.49 days;p = 0.003).

CONCLUSIONS

In orally intubated and mechanically ventilated stroke patients at high risk of severe dysphagia, PES may improve swallowing function, reduce extubation failure risk and decrease time from extubation to discharge. Further research is required.

Management of swallowing disorders in ICU patients - A multinational expert opinion

BACKGROUND

Dysphagia is common in intensive care unit (ICU) patients, yet it remains underrecognized and often unmanaged despite being associated with life-threatening complications, prolonged ICU stays and hospitalization.

PURPOSE

To propose an expert opinion for the diagnosis and management of dysphagia developed from evidence-based clinical recommendations and practitioner insights.

METHODS

A multinational group of dysphagia and critical care experts conducted a literature review using a modified ACCORD methodology. Based on a fusion of the available evidence and the panel's clinical experience, an expert opinion on best practice management was developed.

RESULTS

The panel recommends adopting clinical algorithms intended to promote standardized, high-quality care that triggers timely systematic dysphagia screening, assessment, and treatment of extubated and tracheostomized patients in the ICU.

CONCLUSIONS

Given the lack of robust scientific evidence, two clinical management algorithms are proposed for use by multidisciplinary teams to improve early systematic detection and effective management of dysphagia in ICU patients. Additionally, emerging therapeutic options such as neurostimulation have the potential to improve the quality of ICU dysphagia care.

Relationship between post-stroke dysphagia and pharyngeal sensory impairment

BACKGROUND

Post-stroke dysphagia (PSD) is common and can lead to serious complications. Pharyngeal sensory impairment is assumed to contribute to PSD. The aim of this study was to investigate the relationship between PSD and pharyngeal hypesthesia and to compare different assessment methods for pharyngeal sensation.

METHODS

In this prospective observational study, fifty-seven stroke patients were examined in the acute stage of the disease using Flexible Endoscopic Evaluation of Swallowing (FEES). The Fiberoptic Endoscopic Dysphagia Severity Scale (FEDSS) and impaired secretion management according to the Murray-Secretion Scale were determined, as well as premature bolus spillage, pharyngeal residue and delayed or absent swallowing reflex. A multimodal sensory assessment was performed, including touch-technique and a previously established FEES-based swallowing provocation test with different volumes of liquid to determine the latency of swallowing response (FEES-LSR-Test). Predictors of FEDSS, Murray-Secretion Scale, premature bolus spillage, pharyngeal residue, and delayed or absent swallowing reflex were examined with ordinal logistic regression analyses.

RESULTS

Sensory impairment using the touch-technique and the FEES-LSR-Test were independent predictors of higher FEDSS, Murray-Secretion Scale, and delayed or absent swallowing reflex. Decreased sensitivity according to the touch-technique correlated with the FEES-LSR-Test at 0.3 ml and 0.4 ml, but not at 0.2 ml and 0.5 ml trigger volumes.

CONCLUSIONS

Pharyngeal hypesthesia is a crucial factor in the development of PSD, leading to impaired secretion management and delayed or absent swallowing reflex. It can be investigated using both the touch-technique and the FEES-LSR-Test. In the latter procedure, trigger volumes of 0.4 ml are particularly suitable.

Videofluoroscopic Swallowing Study Features and Resting-State Functional MRI Brain Activity for Assessing Swallowing Differences in Patients with Mild Cognitive Impairment and Risk of Dysphagia

To examine the swallowing characteristics in patients with mild cognitive impairment (MCI) and dysphagia risk and explore brain activity changes using regional homogeneity (ReHo) with resting-state functional magnetic resonance imaging (rs-fMRI). We included 28 patients with MCI and dysphagia risk and 17 age-matched older adults. All participants underwent neurological, cognitive examinations, and a videofluoroscopic swallowing study (VFSS). We quantitatively analyzed the VFSS temporal and kinetic parameters of the 5- and 10-mL swallows. The participants underwent rs-fMRI, and the ReHo values were calculated. Differences in the swallowing physiology and rs-fMRI findings between participants with MCI and controls were analyzed. Correlation analyses were also conducted. Compared to the control group, patients with MCI and dysphagia risk had lower global cognition scores, longer 10-mL oral transit times (OTTs), and lower executive function scores. ReHo in the bilateral inferior occipital lobes (IOLs) and left prefrontal lobe decreased in patients with MCI and dysphagia risk compared to participants in the control group. In patients with MCI, the 10-mL OTT was negatively correlated with the Montreal Cognitive Assessment (MoCA) score, and the ReHo values were positive correlated with quantitative temporal swallowing measurements using canonical correlation analysis. Mediation analysis revealed that the ReHo values of the left and right IOL acted as significant mediators between the MoCA score and the 10-mL OTT. We found that individuals with MCI and dysphagia risk, verified by reduced MoCA scores, demonstrated prolonged OTTs when swallowing larger boluses compared with age-matched controls. There was a negative correlation between the MoCA score and 10-mL OTT, which was partially mediated by the left and right IOL ReHo values, suggesting that functional changes in the IOLs and left prefrontal lobe associated with oral swallowing status and cognitive level in individuals with MCI and dysphagia risk.

Clinical features and power spectral entropy of electroencephalography in Wilson's disease with dystonia

OBJECTIVE

To study the clinical features and power spectral entropy (PSE) of electroencephalography signals in Wilson's disease (WD) patients with dystonia.

METHODS

Several scale evaluations were performed to assess the clinical features of WD patients. Demographic information and electroencephalography signals were obtained in all subjects.

RESULTS

34 WD patients with dystonia were recruited in the case group and 24 patients without dystonia were recruited in the control group. 20 healthy individuals were included in the healthy control group. The mean body mass index (BMI) in the case group was significantly lower than that in the controls (p < .05). The case group had significantly higher SAS, SDS, and Bucco-Facial-Apraxia Assessment scores (p < .05). Total BADS scores in the case group were lower than those in the control group (p < .01). Note that 94.11% of the case group presented with dysarthria and 70.59% of them suffered from dysphagia. Dysphagia was mainly related to the oral preparatory stage and oral stage. Mean power spectral entropy (PSE) values in the case group were significantly different (p < .05) from those in the control group and the healthy group across the different tasks.

CONCLUSIONS

The patients with dystonia were usually accompanied with low BMI, anxiety, depression, apraxia, executive dysfunction, dysarthria and dysphagia. The cortical activities of the WD patients with dystonia seemed to be more chaotic during the eyes-closed and reading tasks but lower during the swallowing stages than those in the control group.

Can Swallowing Cerebral Neurophysiology Be Evaluated during Ecological Food Intake Conditions? A Systematic Literature Review

Swallowing is a complex function that relies on both brainstem and cerebral control. Cerebral neurofunctional evaluations are mostly based on functional magnetic resonance imaging (fMRI) and positron emission tomography (PET), performed with the individual laying down; which is a non-ecological/non-natural position for swallowing. According to the PRISMA guidelines, a review of the non-invasive non-radiating neurofunctional tools, other than fMRI and PET, was conducted to explore the cerebral activity in swallowing during natural food intake, in accordance with the PRISMA guidelines. Using Embase and PubMed, we included human studies focusing on neurofunctional imaging during an ecologic swallowing task. From 5948 unique records, we retained 43 original articles, reporting on three different techniques: electroencephalography (EEG), magnetoencephalography (MEG) and functional near infra-red spectroscopy (fNIRS). During swallowing, all three techniques showed activity of the pericentral cortex. Variations were associated with the modality of the swallowing process (volitional or non-volitional) and the substance used (mostly water and saliva). All techniques have been used in both healthy and pathological conditions to explore the precise time course, localization or network structure of the swallowing cerebral activity, sometimes even more precisely than fMRI. EEG and MEG are the most advanced and mastered techniques but fNIRS is the most ready-to-use and the most therapeutically promising. Ongoing development of these techniques will support and improve our future understanding of the cerebral control of swallowing.

Exploration on neurobiological mechanisms of the central–peripheral–central closed-loop rehabilitation

Central and peripheral interventions for brain injury rehabilitation have been widely employed. However, as patients’ requirements and expectations for stroke rehabilitation have gradually increased, the limitations of simple central intervention or peripheral intervention in the rehabilitation application of stroke patients’ function have gradually emerged. Studies have suggested that central intervention promotes the activation of functional brain regions and improves neural plasticity, whereas peripheral intervention enhances the positive feedback and input of sensory and motor control modes to the central nervous system, thereby promoting the remodeling of brain function. Based on the model of a central–peripheral–central (CPC) closed loop, the integration of center and peripheral interventions was effectively completed to form “closed-loop” information feedback, which could be applied to specific brain areas or function-related brain regions of patients. Notably, the closed loop can also be extended to central and peripheral immune systems as well as central and peripheral organs such as the brain–gut axis and lung–brain axis. In this review article, the model of CPC closed-loop rehabilitation and the potential neuroimmunological mechanisms of a closed-loop approach will be discussed. Further, we highlight critical questions about the neuroimmunological aspects of the closed-loop technique that merit future research attention.

Clinical determinants and neural correlates of presbyphagia in community-dwelling older adults

Background

“Presbyphagia” refers to characteristic age-related changes in the complex neuromuscular swallowing mechanism. It has been hypothesized that cumulative impairments in multiple domains affect functional reserve of swallowing with age, but the multifactorial etiology and postulated compensatory strategies of the brain are incompletely understood. This study investigates presbyphagia and its neural correlates, focusing on the clinical determinants associated with adaptive neuroplasticity.

Materials and methods

64 subjects over 70 years of age free of typical diseases explaining dysphagia received comprehensive workup including flexible endoscopic evaluation of swallowing (FEES), magnetoencephalography (MEG) during swallowing and pharyngeal stimulation, volumetry of swallowing muscles, laboratory analyzes, and assessment of hand-grip-strength, nutritional status, frailty, olfaction, cognition and mental health. Neural MEG activation was compared between participants with and without presbyphagia in FEES, and associated clinical influencing factors were analyzed. Presbyphagia was defined as the presence of oropharyngeal swallowing alterations e.g., penetration, aspiration, pharyngeal residue pooling or premature bolus spillage into the piriform sinus and/or laryngeal vestibule.

Results

32 of 64 participants showed swallowing alterations, mainly characterized by pharyngeal residue, whereas the airway was rarely compromised. In the MEG analysis, participants with presbyphagia activated an increased cortical sensorimotor network during swallowing. As major clinical determinant, participants with swallowing alterations exhibited reduced pharyngeal sensation. Presbyphagia was an independent predictor of a reduced nutritional status in a linear regression model.

Conclusions

Swallowing alterations frequently occur in otherwise healthy older adults and are associated with decreased nutritional status. Increased sensorimotor cortical activation may constitute a compensation attempt to uphold swallowing function due to sensory decline. Further studies are needed to clarify whether the swallowing alterations observed can be considered physiological per se or whether the concept of presbyphagia may need to be extended to a theory with a continuous transition between presbyphagia and dysphagia.

Swallowing function in the chronic stage following stroke is associated with white matter integrity of the callosal tract between the interhemispheric S1 swallowing representation areas

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Swallowing performance was tested in dysphagic patients following stroke.

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M1 and S1 callosal tracts relevant for swallowing was mapped in the HCP-dataset.

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S1 and M1 swallowing tracts were overlapping between in house and HCP datasets.

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Swallowing specific callosal tracts showed lower FA for patients compared to HCs.

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Integrity of S1 callosal fibres (FA) was associated with swallowing performance.

Sensorimotor representations of swallowing in pre- and postcentral gyri of both cerebral hemispheres are interconnected by callosal tracts. We were interested in (1) the callosal location of fibers interconnecting the precentral gyri (with the primary motor cortex; M1) and the postcentral gyri (with the primary somatosensory cortex; S1) relevant for swallowing, and (2) the importance of their integrity given the challenges of swallowing compliance after recovery of dysphagia following stroke. We investigated 17 patients who had almost recovered from dysphagia in the chronic stage following stroke and age-matched and gender-matched healthy controls. We assessed their swallowing compliance, investigating swallowing of a predefined bolus in one swallowing movement in response to a ‘go’ signal when in a lying position. A somatotopic representation of swallowing was mapped for the pre- and postcentral gyrus, and callosal tract location between these regions was compared to results for healthy participants. We applied multi-directional diffusion-weighted imaging of the brain in patients and matched controls to calculate fractional anisotropy (FA) as a tract integrity marker for M1/S1 callosal fibers. Firstly, interconnecting callosal tract maps were well spatially separated for M1 and S1, but were overlapped for somatotopic differentiation within M1 and S1 in healthy participants’ data (HCP: head/face representation; in house dataset: fMRI-swallowing representation in healthy volunteers). Secondly, the FA for both callosal tracts, connecting M1 and S1 swallowing representations, were decreased for patients when compared to healthy volunteers. Thirdly, integrity of callosal fibers interconnecting S1 swallowing representation sites was associated with effective swallowing compliance. We conclude that somatosensory interaction between hemispheres is important for effective swallowing in the case of a demanding task undertaken by stroke survivors with good swallowing outcome from dysphagia.

Motor and sensory cortical processing of neural oscillatory activities revealed by human swallowing using intracranial electrodes

Swallowing is attributed to the orchestration of motor output and sensory input. We hypothesized that swallowing can illustrate differences between motor and sensory neural processing. Eight epileptic participants fitted with intracranial electrodes over the orofacial cortex were asked to swallow a water bolus. Mouth opening and swallowing were treated as motor tasks, whereas water injection was treated as a sensory task. Phase-amplitude coupling between lower-frequency and high γ (HG) bands (75–150 Hz) was investigated. An α (10–16 Hz)-HG coupling appeared before motor-related HG power increases (burst), and a θ (5–9 Hz)-HG coupling appeared during sensory-related HG bursts. The peaks of motor-related coupling were 0.6–0.7 s earlier than that of HG power. The motor-related HG was modulated at the trough of the α oscillation, and the sensory-related HG amplitude was modulated at the peak of the θ oscillation. These contrasting results can help to elucidate the brain's sensory motor functions.

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Swallowing has two aspects; sensory input and motor output

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Phase-amplitude coupling showed differences of motor and sensory neural processing

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Coupling between the α and high γ band occurred before motor-related high γ activities

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Coupling between the θ and high γ band occurred during sensory-related high γ activities