Tongue pressure against hard palate during swallowing in post-stroke patients

Biomechanical and Cortical Control of Tongue Movements During Chewing and Swallowing

Tongue function is vital for chewing and swallowing and lingual dysfunction is often associated with dysphagia. Better treatment of dysphagia depends on a better understanding of hyolingual morphology, biomechanics, and neural control in humans and animal models. Recent research has revealed significant variation among animal models in morphology of the hyoid chain and suprahyoid muscles which may be associated with variation in swallowing mechanisms. The recent deployment of XROMM (X-ray Reconstruction of Moving Morphology) to quantify 3D hyolingual kinematics has revealed new details on flexion and roll of the tongue during chewing in animal models, movements similar to those used by humans. XROMM-based studies of swallowing in macaques have falsified traditional hypotheses of mechanisms of tongue base retraction during swallowing, and literature review suggests that other animal models may employ a diversity of mechanisms of tongue base retraction. There is variation among animal models in distribution of hyolingual proprioceptors but how that might be related to lingual mechanics is unknown. In macaque monkeys, tongue kinematics-shape and movement-are strongly encoded in neural activity in orofacial primary motor cortex, giving optimism for development of brain-machine interfaces for assisting recovery of lingual function after stroke. However, more research on hyolingual biomechanics and control is needed for technologies interfacing the nervous system with the hyolingual apparatus to become a reality.

Maximum lingual pressure impacts both swallowing safety and efficiency in individuals with amyotrophic lateral sclerosis

BACKGROUND

Although reduced lingual strength is a confirmed early manifestation of amyotrophic lateral sclerosis (ALS), its functional impact on swallowing remains unclear. We therefore sought to examine relationships between maximum anterior isometric lingual pressure (MAIP) with swallowing safety, swallowing efficiency, and swallowing timing metrics in a large cohort of individuals with ALS.

METHODS

Ninety-seven participants with ALS completed a standardized videofluoroscopic swallowing examination (VF) and lingual pressure testing (Iowa Oral Performance Instrument). Duplicate and blinded ratings of the Penetration-Aspiration Scale (PAS) and Analysis of Swallowing Physiology: Events, Kinematics and Timing (ASPEKT) percent efficiency (%C2-C42 ) and timing (laryngeal vestibule closure (LVC) duration: amount of time (milliseconds, msec) between LVC onset and laryngeal vestibule opening; time-to-LVC: hyoid burst to onset of LVC (msec); and swallow reaction time: interval between bolus passing ramus of mandible and onset of LVC (msec)) were performed across bolus trials. Swallowing safety (safe PAS: 1, 2, 4; unsafe PAS: 3, 5, 6, 7, and 8) and efficiency (inefficient: ≥3% worst total residue) were derived. Statistical analyses including descriptives, binary logistic regressions, and Spearman's rho correlations were performed (α = 0.05).

KEY RESULTS

Mean MAIP was 36.3 kPa (SD: 18.7). Mean MAIP was higher in those with safe swallowing as compared to those who penetrated (mean difference: 12 kPa) or aspirated (mean difference: 18 kPa). Individuals with efficient swallowing demonstrated higher MAIP than those with inefficient swallowing (mean difference: 11 kPa). Binary logistic regression analyses revealed increasing MAIP was significantly associated with a 1.06 (95% CI: 1.03-1.09) and 1.04 (95% CI: 1.01-1.06) greater odds of safe and efficient swallowing, respectively. No relationships were observed between MAIP and swallow reaction time across all bolus trials. Longer time-to-LVC (5 ml thin liquid: rs  = -0.35, p = 0.002; cup sip thin liquid: rs  = -0.26, p = 0.02; moderately thick liquid: rs  = -0.28, p = 0.01) and prolonged LVC duration (cup sip thin liquid, rs  = -0.34, p = 0.003) were associated with lower MAIP.

CONCLUSIONS AND INFERENCES

Reduced lingual strength was confirmed in this group of 97 individuals with ALS that was associated with a diminished ability to effectively transport boluses and aide in laryngeal vestibule closure to prevent entry of material into the airway.

Aspiration Risk Screening With Tongue Pressure Measurement in Acute Stroke: A Diagnostic Accuracy Study Using STARD Guidelines

Introduction

Dysphagia can affect more than 50% of stroke patients in the acute phase. Aspiration pneumonia is a serious complication that can be prevented with dysphagia screening and assessment. Measurement of tongue elevation pressure is suggested to be a useful tool in aspiration risk screening.

Objective

This study aimed to assess the diagnostic accuracy of maximum anterior tongue elevation strength (Pmax) in acute stroke care.

Method

In this prospective study, data were collected in a neurology department (stroke center) where patients formed a consecutive case series. The sample consisted of thirty stroke patients who failed an initial dysphagia screening. Patients underwent anterior tongue elevation strength measurement (index test) during bedside dysphagia assessment by a speech-language pathologist and flexible endoscopic evaluation of swallowing (reference test) by an otorhinolaryngologist on the same day. Outcome variables (index values in kPa, reference values interpreted on the penetration-aspiration scale) were used for estimating measures of diagnostic accuracy in aspiration risk screening.

Results

Ten patients aspirated on instrumental evaluation. At the cut-off point of ≤ 34 kPa the analysis showed 90% sensitivity, 35% specificity, 41% positive predictive value, and 88% negative predictive value. The area under the curve (AUC) for Pmax was AUC = 0.700 (95% CI [0.500-0.900]).

Conclusion

Although individuals with low anterior tongue elevation strength tend to have a higher risk of aspiration, this variable alone is not capable of screening aspiration in acute stroke. In combination with a thorough noninstrumental bedside examination, it might have the potential to reduce the number of false positive cases. Further studies in this area would be worthwhile.

Clinical Characteristics and Rehabilitation Strategies for the Stomatognathic System Disturbances in Patients with Stroke: A Systematic Review

Background: Understanding the stomatognathic system disturbances is key to diagnosing them early and implementing rehabilitation approaches to promote functional recovery. The objective of this study was to systematically review all published data that examined the assessment and rehabilitation strategies for the stomatognathic system disturbances in patients with stroke. Methods: Five databases (i.e., PubMed/MEDLINE, Scopus, Science Direct, Web of Science, and PEDro), were screened for manuscripts that included the assessment and rehabilitation strategies for stomatognathic system disturbances. The methodological quality was evaluated using the Mixed Methods Appraisal Tool. Results: Sixteen articles were included in this systematic review. The most frequently reported symptoms in patients with stroke included stiffness and thickness of the masseter muscle on the affected side and suprahyoid muscles; facial muscles' asymmetry and weakness; temporomandibular disorders; and a reduced maximum lip force, tongue pressure, and saliva flow rate. The rehabilitation strategies more frequently reported included exercises directed to the jaw, temporomandibular joint, tongue, and neck. The mean score for methodological quality was 85%. Conclusion: The stomatognathic system disturbances are frequently reported among patients with stroke, leading to dysfunction in masticatory performance or swallowing. More studies on interventions for stomatognathic system disturbances are required before conclusions may be drawn. Key Practitioner Message: This systematic review has clinical implications for rehabilitation practices, given that the results may help to develop early assessment and rehabilitation strategies for stomatognathic disturbances in patients with stroke.

Bibliometric analysis of global research trends on post-stroke pneumonia: Current development status and research Frontiers

Background

As one of the most common complications of stroke, post-stroke pneumonia significantly increases the incidence of adverse outcomes, mortality, and healthcare costs for patients with stroke. As the field of post-stroke pneumonia has gained interest in the recent years, there has been an increasing number of publications on post-stroke pneumonia research worldwide. Therefore, a more comprehensive understanding of the field is needed now. This paper is intended to analyze the research status and detect the research frontiers in this field.

Methods

VOS viewer, CiteSpace, and the online scientometric platform (https://bibliometric.com/) were the main visualization tools used in this paper. They were used to perform citation analysis of countries/institutions, co-citation analysis of authors/journals/references, co-authorship analysis of authors, co-occurrence analysis of keywords, and citation bursts analysis of references.

Results

The number of publications in this field has increased rapidly since 2010 and is expected to continue to increase in the next few years. The countries contributing most to post-stroke pneumonia research were the USA, China, and Germany. The most productive institution was Harvard University, followed by Humboldt University of Berlin, Charité Universitätsmedizin Berlin, and Free University of Berlin from Germany. Meanwhile, the German authors Meisel A, Meisel C, and Dirnagl U, who have contributed significantly to this field, were all associated with these three German institutions. The high-quality and high output journal was STROKE. In the coming years, the hot topic keywords “risk & risk-factors,” “outcome & impact,” “management & guidelines,” and “predictors” will gain more attention in this field. Finally, hot keywords were grouped into four clusters in this paper: cluster 1 (risk-factors studies of post-stroke pneumonia), cluster 2 (clinically relevant studies of post-stroke pneumonia), cluster 3 (mechanism studies of post-stroke pneumonia), and cluster 4 (care studies of post-stroke pneumonia).

Conclusion

This study shows the knowledge structure and evolution of the field of post-stroke pneumonia research and predicts research trends through visualization analysis. The future trend of post-stroke pneumonia research will gradually shift from clinical and mechanistic studies to treatment and prevention studies.

Profiles of Swallowing Impairment in a Cohort of Patients With Reduced Tongue Strength Within 3 Months of Cerebral Ischemic Stroke

PURPOSE

Patients with poststroke dysphagia may experience inefficient bolus clearance or inadequate airway protection. Following a stroke, impairments in lingual pressure generation capacity are thought to contribute to oropharyngeal dysphagia. The goal of our study was to determine whether similar profiles of swallowing impairment would be seen across a cohort of patients with reduced tongue strength within 3 months after cerebral ischemic stroke.

METHOD

The sample comprised six adults with reduced tongue strength (i.e., maximum anterior isometric pressure < 40 kPa). Participants underwent a videofluoroscopy according to a standard protocol. Post hoc blinded ratings were completed using the Analysis of Swallowing Physiology: Events, Kinematics and Timing Method and coded as "typical" versus "atypical" (i.e., within vs. outside the healthy interquartile range) in comparison to published reference values.

RESULTS

The videofluoroscopies suggested that having reduced tongue strength did not translate into a common profile. Of the six participants, two showed Penetration-Aspiration Scale (PAS) scores of ≥ 3 on thin liquids, associated with incomplete laryngeal vestibule closure (LVC). Another two participants displayed PAS scores of 2 (transient penetration), but these were not associated with incomplete LVC. Pharyngeal residue, above the healthy 75th percentile, was seen for three participants. Five participants presented with atypical reductions in hyoid XY peak position.

CONCLUSIONS

In this cohort of adults within 3 months of cerebral ischemic stroke, reductions in tongue strength presented alongside a variety of changes in swallowing physiology. There was no straightforward relationship linking reduced tongue strength to particular patterns of impairment on videofluoroscopy.

Comparison of Lingual Pressure Generation Capacity in Parkinson Disease, Amyotrophic Lateral Sclerosis, and Healthy Aging

PURPOSE

The tongue plays a key role in bolus propulsion during swallowing, with reduced lingual pressure generation representing a risk factor for impaired swallowing safety and efficiency. We compared lingual pressure generation capacity in people with Parkinson disease (PwPD), people with amyotrophic lateral sclerosis (PwALS), and healthy older adults. We hypothesized that both patient cohorts would demonstrate reduced maximum anterior isometric pressure (MAIP) and regular effort saliva swallow (RESS) pressures compared with healthy controls, with the greatest reductions expected in the ALS cohort.

METHOD

We enrolled 20 PwPD, 18 PwALS, and 20 healthy adults over 60 years of age. The Iowa Oral Performance Instrument was used to measure MAIP, RESS, and lingual functional reserve (LFR, i.e., MAIP - RESS). Descriptive statistics were calculated; between-groups differences were explored using univariate analyses of variance and post hoc Sidak tests with alpha set at .05.

RESULTS

Mean MAIPs for the PD, ALS, and heathy cohorts were 54.7, 33.5, and 47.4 kPa, respectively. Significantly lower MAIP was found in PwALS compared with PwPD and healthy controls. RESS values did not differ significantly across groups. LFR was significantly higher in PwPD versus PwALS and healthy controls.

CONCLUSIONS

Lingual pressure generation capacity and functional reserve were reduced in PwALS, but not in PwPD, beyond changes seen with healthy aging. Both patient cohorts displayed preserved lingual pressure during saliva swallows. Future studies exploring longitudinal changes in tongue pressure generation on isometric and saliva swallowing tasks will be needed to confirm whether tongue pressure measures serve as noninvasive clinical biomarkers of swallowing impairment.

Palatal Electrotactile Display Outperforms Visual Display in Tongue Motor learning

Incomplete tongue motor control is a common yet challenging issue among individuals with neurotraumas and neurological disorders. In development of the training protocols, multiple sensory modalities including visual, auditory, and tactile feedback have been employed. However, the effectiveness of each sensory modality in tongue motor learning is still in question. The object of this study was to test the effectiveness of visual and electrotactile assistance on tongue motor learning, respectively. Eight healthy subjects performed the tongue pointing task, in which they were visually instructed to touch the target on the palate by their tongue tip as accurately as possible. Each subject wore a custom-made dental retainer with 12 electrodes distributed over the palatal area. For visual training, 3×4 LED array on the computer screen, corresponding to the electrode layout, was turned on with different colors according to the tongue contact. For electrotactile training, electrical stimulation was applied to the tongue with frequencies depending on the distance between the tongue contact and the target, along with a small protrusion on the retainer as an indicator of the target. One baseline session, one training session, and three post-training sessions were conducted over four-day duration. Experimental result showed that the error was decreased after both visual and electrotactile trainings, from 3.56±0.11 (Mean±STE) to 1.27±0.16, and from 3.97±0.11 to 0.53±0.19, respectively. The result also showed that electrotactile training leads to stronger retention than visual training, as the improvement was retained as 62.68±1.81% after electrotactile training and 36.59±2.24% after visual training, at 3-day post training.

An instrument for tongue performance assessment in activities associated with digital games: content and construct validity

ABSTRACT Purpose: to analyze the content and construct validity of an instrument for tongue performance assessment in activities associated with digital games. Methods: to analyze content validity, ten speech-language pathologists answered a questionnaire in which each item of the instrument and the set of items were judged as to its representativeness. The content validity index and the modified Kappa statistics were calculated. To analyze construct validity, 20 participants, with age between 8 and 13 years, (10 children with weak tongues and 10 children with normal tongue strength) performed a game activity with the T-Station, involving 12 targets with 2 N of strength and 5 s of time for sustained contraction for each target. The performance was compared, for each item of the instrument, between groups. Results: most of the items obtained satisfactory score according to the speech-language pathologist’s evaluation. Children with reduced tongue force had a poorer performance than those with normal tongue force, with a statistically significant difference in three items of the instrument. Conclusion: the instrument proved to be valid as a method for evaluating performance in activities associated with the T-Station.

Study of tongue-palate pressure patterns during the hold phase in the production of French denti-alveolar and velar stops

The hold phase of the stop consonants is crucial for a successful production of the release and the acoustic burst. Concurrently, it is also associated with weak acoustic energy and minimal movement, so that conventional acoustic and kinematic approaches are not relevant to investigate motor control. This paper presents an innovative experimental method to study speech motor control during this phase, based on meticulous measurement of the time variation of the mechanical pressure exerted by the tongue against the palate and also characterizing tongue-palate interaction. The concept is based on using miniature transducers with enhanced response characteristics inserted in different locations of the complete denture of edentulous subjects without perturbing the articulation. The study was done with a French-speaking adult whose maxillary denture was duplicated and mounted with six strain gauge transducers. The experiment was done with denti-alveolar and velar stop consonants with two vowel contexts. The results illustrate the potential of such device to analyse speech motor control when contact constrains tongue movements.

Reduced tongue force and functional swallowing changes in a rat model of post stroke dysphagia

PURPOSE

Dysphagia is a common problem after stroke that is often associated with tongue weakness. However, the physiological mechanisms of post-stroke tongue muscle weakness and optimal treatments have not been established. To advance understanding of physiological mechanisms of post stroke dysphagia, we sought to validate the unilateral transient middle cerebral artery occlusion (MCAO) rat model of ischemic stroke as a translational model of post stroke dysphagia. Our goal was to establish clinically relevant measures and chronicity of functional deficits; criteria that increase the likelihood that findings will translate to the clinic. We hypothesized that MCAO would cause tongue weakness and functional swallowing changes.

METHODS

Maximum voluntary tongue forces and videofluoroscopic swallowing studies were collected in 8-week old male Sprague-Dawley rats prior to receiving either a left MCAO (N = 10) or sham (N = 10) surgery. Tongue forces and VFSS were reassessed at 1 and 8 weeks post-surgery.

RESULTS

Maximum voluntary tongue force, bolus area, and bolus speed were significantly reduced in the MCAO group at the 1 and 8-week timepoints.

CONCLUSION

Clinically relevant changes to swallowing and tongue force support the use of the MCAO rat model as a translational model of post stroke dysphagia. This model will allow for future studies to improve our understanding of the physiology contributing to these functional changes as well as the impact of therapeutic interventions on physiological targets and function.

Osseous Loading by a Volume-Reduced Tongue During Muscle Contractions

PURPOSE

To investigate how tongue volume reduction affects loads on surrounding bone surfaces produced by neuromuscular stimulation of the tongue.

MATERIALS AND METHODS

Of each pair of same-gender minipig siblings, 1 received tongue reduction and 1 underwent sham surgery. Either immediately (acute, 6 pairs) or 1 month (chronic, 5 pairs) after surgery, bone surface and/or suture strains and pressures were recorded from the following locations when the hypoglossal nerve trunk, hypoglossal nerve medial branch, hypoglossal nerve lateral branch, genioglossus, and styloglossus (SG) were electrically stimulated: 1) three rosette strain gauges on the premaxillary palatal surface (premaxilla [PM]) and lingual surfaces of the mandibular alveolus at anterior (mandibular incisor [MI]) and posterior (mandibular molar [MM]) locations; 2) two single-element strain gauges over the palatal surface of the premaxillary-maxillary suture and the lingual surface of the mandibular symphysis; and 3) two pressure transducers on the palatal surface of the maxilla (palatal process) and the lingual surface of the mandibular alveolus (mandibular corpus).

RESULTS

Compared with the sham animals in the acute study, reduction animals showed significantly decreased PM and MI strains, as well as palatal process pressure. With muscle contractions, mandibular symphysis and MM strains were enhanced significantly with a more dorsal orientation. In the chronic study, reduction animals showed decreased PM and increased MM strains. On comparison of chronic versus acute studies, PM, MI, and MM strains under SG stimulation were significantly smaller whereas MM strain was significantly larger under hypoglossal nerve trunk, hypoglossal nerve lateral branch, and SG stimulations.

CONCLUSIONS

Muscle contractions from a volume-reduced tongue produce lower and higher loads in the anterior and posterior mouth, respectively. However, although the effects on reducing loads in the anterior mouth are persisting over time, compensatory load enhancement in the posterior mouth diminishes owing to surgical healing.

Oral care after stroke: Where are we now?

Purpose

There appears to be an association between poor oral hygiene and increased risk of aspiration pneumonia - a leading cause of mortality post-stroke. We aim to synthesise what is known about oral care after stroke, identify knowledge gaps and outline priorities for research that will provide evidence to inform best practice.

Methods

A narrative review from a multidisciplinary perspective, drawing on evidence from systematic reviews, literature, expert and lay opinion to scrutinise current practice in oral care after a stroke and seek consensus on research priorities.Findings: Oral care tends to be of poor quality and delegated to the least qualified members of the caring team. Nursing staff often work in a pressured environment where other aspects of clinical care take priority. Guidelines that exist are based on weak evidence and lack detail about how best to provide oral care.

Discussion

Oral health after a stroke is important from a social as well as physical health perspective, yet tends to be neglected. Multidisciplinary research is needed to improve understanding of the complexities associated with delivering good oral care for stroke patients. Also to provide the evidence for practice that will improve wellbeing and may reduce risk of aspiration pneumonia and other serious sequelae.

Conclusion

Although there is evidence of an association, there is only weak evidence about whether improving oral care reduces risk of pneumonia or mortality after a stroke. Clinically relevant, feasible, cost-effective, evidence-based oral care interventions to improve patient outcomes in stroke care are urgently needed.

Assessment of Temporomandibular Joint Dysfunction in Patients with Stroke

GOAL

The aim of this study was to assess temporomandibular joint dysfunction in patients with stroke.

MATERIALS AND METHODS

Total of 100 participants, 50 healthy and 50 who had stroke, were recruited into this study. Digital caliper and algometer were used to assess temporomandibular joint range of motion and masticatory muscle pressure pain threshold. Labial commissure angle measurement was used for the assessment of facial paralysis severity. Fonseca questionnaire was used for temporomandibular joint dysfunction assessment and categorization. In addition, dominant mastication shift was measured by the question that asks the pre and poststroke dominant mastication side.

FINDINGS

In intergroup comparison, significant decrease was found in all temporomandibular range of motion parameters in favor of stroke group (P < .05). Despite the fact that no significant difference was found between groups for the pain threshold in masticatory muscles except for middle part of the left temporalis muscle, values were higher in healthy group (P > .05). As a result of intergroup examination of labial commissure angle degree, Fonseca questionnaire score, it was found that labial commissure angle and Fonseca questionnaire scores were higher in stroke group (P < .05). Intragroup examination of patients with stroke showed that dominant mastication side shift was seen in patients with stroke (P < .05).

CONCLUSION

It was concluded that, temporomandibular joint dysfunction prevalence was higher in stroke group compared with healthy group and use of modalities specific to temporomandibular joint dysfunction treatment would be beneficial.

Oro-facial impairment in stroke patients

Stroke is considered one of the leading causes of death and acquired disability with a peak prevalence over the age of 80 years. Stroke may cause debilitating neurological deficiencies that frequently result in sensory deficits, motor impairment, muscular atrophy, cognitive deficits and psychosocial impairment. Oro-facial impairment may occur due to the frequent involvement of the cranial nerves' cortical representation areas, central nervous system pathways or motoneuron pools. The aim of this narrative, non-systematic review was to discuss the implications of stroke on oro-facial functions and oral health-related quality of life (OHRQoL). Stroke patients demonstrate an impaired masticatory performance, possibly due to reduced tongue forces and disturbed oral sensitivity. Furthermore, facial asymmetry is common, but mostly discrete and lip restraining forces are reduced. Bite force is not different between the ipsi- and contra-lesional side. In contrast, the contra-lesional handgrip strength and tongue-palate contact during swallowing are significantly impaired. OHRQoL is significantly reduced mainly because of the functional impairment. It can be concluded that impaired chewing efficiency, dysphagia, facial asymmetry, reduced lip force and OHRQoL are quantifiable symptoms of oro-facial impairment following a stroke. In the absence of functional rehabilitation, these symptoms seem not to improve. Furthermore, stroke affects the upper limb and the masseter muscle differently, both, at a functional and a morphological level. The rehabilitation of stroke survivors should, therefore, also seek to improve the strength and co-ordination of the oro-facial musculature. This would in turn help improve OHRQoL and the masticatory function, subsequently preventing weight loss and malnutrition.

Oral tactile sensitivity and masticatory performance are impaired in stroke patients

Oro-facial impairment following stroke frequently involves reduced chewing performance, that is oral phase dysphagia. The aim was to investigate the sensitivity of oral tissues following stroke and its potential impact on masticatory function. Therefore, hospitalised post-stroke patients were recruited and compared to healthy controls. Outcome measures comprised masticatory performance employing a colour-mixing ability, that is a bolus-kneading test, maximum lip- and bite force and the one-point and two-point tactile thresholds. Food hoarding and prevalence of dry mouth were evaluated with ordinal scales. Twenty-seven stroke patients (age 64·3 ± 14·1 years) and 27 healthy controls (age 60·8 ± 14·3 years, P = 0·254) participated in this study. The groups had similar numbers of occluding units. Stroke patients reported more frequently dry mouth sensations and food hoarding. The intra-oral tactile sensitivity on the contra-lesional side was significantly lower in stroke patients compared to controls (0·0001 < P < 0·0002), and significant intra-group side differences were found only in the stroke group (0·0001 < P < 0·0010). For the lip, both sides were less sensitive in the stroke group compared with controls. The experiments confirmed lower masticatory performance and lip force in the stroke group, but the bite force was similar compared to healthy controls. Oral sensitivity was correlated with masticatory performance when a global correlation model was applied. A stroke may affect the sensitivity of the intra-oral tissues contra-lesionally, thus potentially affecting chewing function. Rehabilitation should therefore not only focus on motor impairment, but equally stimulate the sensitivity of the oral tissues, employing dry ice application or similar specific treatments.

Palatal morphology changes in post-stroke patients measured by geometric morphometrics

This study aimed to describe longitudinal palatal shape changes in post-stroke patients when compared to a sample of healthy subjects through linear measurements and geometric morphometrics. The 3D palatal scanned models of seven stroke patients having a 1-year post-stroke follow-up were matched with seven control subjects of the same age group (range 50-87 years). Intercanine, intermolar distances and palatal height were measured. 3D images were also analysed through geometric morphometrics to assess changes in the shape of the palate from T0 to T1 (1 year after the stroke). Principal component analysis was used to describe shape morphology changes, and visual colour maps were used to qualitatively assess differences between T0 and T1. No changes were detected nor in linear measures neither in palatal shape in healthy subjects from T0 to T1. The palates of stroke patients showed no linear differences either. However, when visualising shape changes through colour maps, the lateral aspects of the palatal vault were slightly narrower in T1, with respect to T0 in stroke patients. This may be attributed to altered tongue function following the stroke.

Relationship between perception of tongue position and measures of tongue force on the teeth

Purpose

To verify whether there are differences of tongue force on the teeth at rest and during swallowing between individuals who report appropriate tongue position and those who report tongue thrust.

Methods

Tongue forces on the teeth were evaluated in 28 participants aged 19 to 31 years. To this end, a Flexiforce® resistive sensor was fixed to the palatal surface of the maxillary right central incisor (tooth 8) and was connected to an amplifier circuit, a data acquisition board, and a computer. Measurements were taken at rest and during saliva swallowing. Participants were asked about their habitual tongue position and where the apex of tongue touched when they swallowed. The Mann Whitney test was used for statistical analysis at 5% significance level.

Results

At habitual position, tongue force on the teeth was 0.00 N both for participants that reported tongue touch and for those who did not. At directed swallowing, tongue force was 0.34 N for the group of individuals whose tongues touch the teeth and 0.08 N for the group of individuals whose tongues do not touch the teeth. This difference was significant.

Conclusion

No significant difference was found between the tongue forces of participants of both groups at habitual position. However, participants with tongue thrust during directed swallowing presented greater force than those whose tongues do not touch the teeth during this task.

Tongue pressure production during swallowing in patients with mandibular prognathism

Abnormalities of swallowing in patients with mandibular prognathism have not been evaluated quantitatively. The aim of this study was to compare tongue pressure production for bolus transfer between volunteers with normal occlusion and patients with mandibular prognathism. The control group had 10 female volunteers with normal occlusion, and the patient group had 10 women with mandibular prognathism. Tongue pressure was measured by a palatal sensor sheet at five sites on swallowing 4 mL of a tasteless and odourless jelly.

RESULTS

The tongue pressure waveform differed between the control and patient groups. The incidence of a double-peak tongue pressure waveform was more frequent in the patient group. In both groups, the exertion of tongue pressure began at the anterior point of the sensor sheet, followed by the peripheral parts. Although the order of expression of tongue pressure was the same for the two groups, maximum tongue pressure at all parts of the sensor sheet was lower in the patient group than in the control group. Furthermore, swallowing time was longer in the patient group than in the control group at the peripheral parts of the palate. These results clearly show the difference in tongue pressure production during swallowing between patients with mandibular prognathism and volunteers with normal occlusion. The current findings suggest that maxillofacial morphology may affect tongue movement during swallowing.

Bedside diagnosis of dysphagia: a systematic review

Dysphagia is associated with aspiration, pneumonia, and malnutrition, but remains challenging to identify at the bedside. A variety of exam protocols and maneuvers are commonly used, but the efficacy of these maneuvers is highly variable. We conducted a comprehensive search of 7 databases, including MEDLINE, Embase, and Scopus, from each database's earliest inception through June 9, 2014. Studies reporting diagnostic performance of a bedside examination maneuver compared to a reference gold standard (videofluoroscopic swallow study or flexible endoscopic evaluation of swallowing with sensory testing) were included for analysis. From each study, data were abstracted based on the type of diagnostic method and reference standard study population and inclusion/exclusion characteristics, design, and prediction of aspiration. The search strategy identified 38 articles meeting inclusion criteria. Overall, most bedside examinations lacked sufficient sensitivity to be used for screening purposes across all patient populations examined. Individual studies found dysphonia assessments, abnormal pharyngeal sensation assessments, dual axis accelerometry, and 1 description of water swallow testing to be sensitive tools, but none were reported as consistently sensitive. A preponderance of identified studies was in poststroke adults, limiting the generalizability of results. No bedside screening protocol has been shown to provide adequate predictive value for presence of aspiration. Several individual exam maneuvers demonstrated reasonable sensitivity, but reproducibility and consistency of these protocols was not established. More research is needed to design an optimal protocol for dysphagia detection.

OroPress a new wireless tool for measuring oro-lingual pressures: a pilot study in healthy adults

Background

Commercially available tools for measuring oro-lingual pressures during swallowing or isometric (tongue ‘pushing’) tasks have either poor, or unknown, psychometric properties (stability, reliability) which means their validity in a clinical setting is unknown. A new wireless tool, OroPress, has been designed to address the shortcomings of existing devices. In this pilot cohort study of normal adults (i.e., people without dysphagia), the face validity of OroPress was examined when it was used to measure oro-lingual pressures during (i) isometric tongue strength (ITS) tasks and (ii) isometric tongue endurance (ITE) tasks.

The effects of gender on isometric oro-lingual data, captured using OroPress, were compared to published oro-lingual pressure data recorded using either the Kay Swallowing Workstation or the Iowa Oral Performance Instrument (aka commercial tools).

Methods

Thirty five adults (17 males, 18 females), were purposefully recruited at the University of Limerick (UL), Ireland. They attended one session at the university-based clinic where their oro-lingual pressures were recorded while undertaking two isometric tasks by speech and language therapy student clinicians. OroPress was used to capture tongue strength and tongue endurance pressures during two trials of each condition and data were downloaded and analysed post-hoc. An independent-samples t-test and an ANOVA were used to examine the effect of gender on ITS pressures (as data were normally distributed) and an independent-samples t-test was used for the effect of gender on ITE pressures (where data were not normally distributed).

Results

OroPress is a portable tool that was reported as being ‘easy to use’ by student SLT clinicians. The intra-oral sensor was reportedly comfortable and ‘felt non-invasive’ for participants. Data from 34 participants (16 males, 18 females) are reported.

Males did not demonstrate significantly higher mean ITS pressures than females (P = 0.057), although this approached significance, and there was no gender effect for ITE oro-lingual pressure. These results were consistent with published data from studies where other tools have been used to measure ITS pressures.

Conclusions

Preliminary face validity of OroPress as a tool for recording isometric oro-lingual pressures was supported. This new wireless tool shows promise for being a criterion standard for recording oro-lingual pressures during isometric tasks.

Evaluation of the force applied by the tongue and lip on the maxillary central incisor tooth

PURPOSE

To describe the development and testing of a system that measures forces exerted by the tongue and upper lip on a tooth during rest and during swallowing.

METHODS

Twenty-eight subjects, aged 19-31 years (mean: 23.2 years) were submitted to measurement of forces exerted by the upper lip and tongue on the maxillary right central incisor tooth. Flexiforce resistive sensors were fixed on the labial and lingual surfaces of the tooth. They were connected to an amplifier circuit and a data acquisition board for processing and transmitting information to a computer.

RESULTS

At rest, the tongue force on the tooth was 0.00±0.00 N and the lip force on tooth was 0.02±0.02 N. The difference between them was significant. During swallowing, the values were 0.31±0.38 N and 0.15±0.14 N, for the tongue and lip, respectively. This difference was not significant.

CONCLUSION

At rest, the lip exerts a larger force than the tongue on the maxillary right central incisor tooth. During swallowing, there was no difference between lip and tongue force on the tooth.

Sequential coordination between lingual and pharyngeal pressures produced during dry swallowing

The aim of this study was to investigate oropharyngeal pressure flow dynamics during dry swallowing in ten healthy subjects. Tongue pressure (TP) was measured using a sensor sheet system with five measuring points on the hard palate, and pharyngeal pressure (PP) was measured using a manometric catheter with four measuring points. The order and correlations of sequential events, such as onset, peak, and offset times of pressure production, at each pressure measuring point were analyzed on the synchronized waveforms. Onset of TP was earlier than that of PP. The peak of TP did not show significant differences with the onset of PP, and it was earlier than that of PP. There was no significant difference between the offset of TP and PP. The onset of PP was temporally time-locked to the peak of TP, and there was an especially strong correlation between the onset of PP and TP at the posterior-median part on the hard palate. The offset of PP was temporally time-locked to that of TP. These results could be interpreted as providing an explanation for the generation of oropharyngeal pressure flow to ensure efficient bolus transport and safe swallowing.

A systematic review and meta-analysis of clinical, microbiological, and behavioural aspects of oral health among patients with stroke

OBJECTIVE

The objective of this study was to review clinical, microbiological, and immunological aspects of oral health, as well as oral health related behaviours among patients following stroke.

DATA SOURCES

A structured search strategy was applied to three electronic databases to identify relevant papers.

STUDY SELECTION

The initial search yielded 19,927 papers, 60 potentially relevant studies (Kappa: 0.974) and 23 relevant papers (Kappa: 0.965) in accordance with the inclusion criteria. Outcomes regarding tooth condition, periodontal condition, oral hygiene status, and dental attendance were pooled for seven meta-analyses. Narrative summaries were provided for those outcomes which could not be pooled for meta-analysis.

RESULTS

The standardized differences in mean values of the parameters (fixed effect, random effect model) for patients with stroke compared to control groups were: number of teeth (-0.325, -0.271), DMFT (0.246, 0.246), oral hygiene status - plaque index (0.305, 0.356) and gingival index (0.716, 0.653), periodontal health status - clinical attachment loss (0.437, 0.490) and probing depth (0.470, 0.579). In addition, a lower chance of dental attendance was observed among patients with stroke (odds ratio: 0.493, 0.480). For those outcomes which could not be pooled for meta-analysis, it was not possible to draw any qualitative conclusion due to the equivocal results of these studies.

CONCLUSIONS

There is an increasing interest in oral health of patients with stroke. Patients with stroke had a poorer clinical oral health status across a range of parameters (tooth loss, dental caries experience, and periodontal status). Coupled with this, their dental attendance was less frequent. Further studies employing standardized assessments of oral health/oral health behaviour can confirm these oral health disparities.

CLINICAL SIGNIFICANCE

With comprehensive literature search, this systematic review and meta-analysis indicated a poorer oral health status and less frequent dental attendance behaviour among patients with stroke.

Tongue pressure modulation for initial gel consistency in a different oral strategy

Background

In the recent hyper-aged societies of developed countries, the market for soft diets for patients with dysphagia has been growing and numerous jelly-type foods have become available. However, interrelationships between the biomechanics of oral strategies and jelly texture remain unclear. The present study investigated the influence of the initial consistency of jelly on tongue motor kinetics in different oral strategies by measuring tongue pressure against the hard palate.

Methods

Jellies created as a mixture of deacylated gellan gum and psyllium seed gum with different initial consistencies (hard, medium or soft) were prepared as test foods. Tongue pressure production while ingesting 5 ml of jelly using different oral strategies (Squeezing or Mastication) was recorded in eight healthy volunteers using an ultra-thin sensor sheet system. Maximal magnitude, duration and total integrated values (tongue work) of tongue pressure for size reduction and swallowing in each strategy were compared among initial consistencies of jelly, and between Squeezing and Mastication.

Results

In Squeezing, the tongue performed more work for size reduction with increasing initial consistency of jelly by modulating both the magnitude and duration of tongue pressure over a wide area of hard palate, but tongue work for swallowing increased at the posterior-median and circumferential parts by modulating only the magnitude of tongue pressure. Conversely, in Mastication, the tongue performed more work for size reduction with increasing initial consistency of jelly by modulating both magnitude and duration of tongue pressure mainly at the posterior part of the hard palate, but tongue work as well as other tongue pressure parameters for swallowing showed no differences by type of jelly.

Conclusions

These results reveal fine modulations in tongue-palate contact according to the initial consistency of jelly and oral strategies.

Prognostic value of decreased tongue strength on survival time in patients with amyotrophic lateral sclerosis

Decreased tongue strength (TS) might herald bulbar involvement in patients with amyotrophic lateral sclerosis (ALS) well before dysarthria or dysphagia occur, and as such might be prognostic of short survival. The purpose of this study was to investigate the prognostic value of a decreased TS, in addition to other prognostic factors, such as site of onset, bulbar symptoms, bulbar signs, age, sex, maximum phonation time, time from symptoms to diagnosis, and gastrostomy, for survival time in patients with ALS. TS was measured in four directions in 111 patients who attended the diagnostic outpatient motor neuron clinic of our university hospital. Of these patients, 54 were diagnosed with ALS. TS was considered abnormal if the strength in minimally one direction was at least two standard deviations below the reference values obtained from comparable age category and sex-groups of healthy controls (n = 119). Twenty of the patients with ALS had a decreased TS. Multivariable analysis showed that, in addition to age, TS was an independent prognostic factor for survival time in patients with ALS.