Tongue control for swallowing in Parkinson's disease: effects of age, rate, and stimulus consistency

Cough Correlates of Functional Swallow Outcomes in Atypical Parkinsonism

BACKGROUND

Swallow and cough impairments lead to aspiration and reduced clearance of aspirate material. Both behaviors are impaired in Parkinson's disease, but it is unknown whether a similar relationship of dysfunction exists in forms of atypical Parkinsonism (APD). Elucidating this association in APD may lead to early, comprehensive airway protection treatment.

OBJECTIVES

We tested the hypotheses that swallow deficits in APD are associated with impaired cough and that airway protective dysfunction is associated with longer disease duration.

METHODS

Swallowing difficulty was described by 11 participants with APD. Penetration-Aspiration Scale (PAS) and DIGEST scores for thin liquid trials were extracted from medical records of videofluoroscopic swallow study reports. Voluntary and capsaicin induced-reflex cough measures of flow, volume, and timing were analyzed.

RESULTS

While most participants did not have post-swallow residue, ~80% received abnormal PAS scores and reported swallowing difficulty. Those with abnormal PAS scores had lower voluntary cough expired volume (P = 0.037; mean rank difference = 5.0); lower reflex inspiratory flow rate (P = 0.034; mean rank difference = 5.5); and longer reflex expiratory flow rise time (P = 0.034; mean rank difference = 5.5). Higher PAS scores and reduced reflex cough volume acceleration were significantly correlated (r = -0.63; P = 0.04) and longer disease duration predicted larger voluntary cough expired volume (R2  = 0.72) and longer flow rise times (R2  = 0.47).

CONCLUSIONS

As swallow safety worsens, so might the ability to clear the airways with effective cough in in APD; particularly with longer disease duration. Assessing cough in conjunction with swallowing is important for informing airway protection treatment plans in APD.

Reproducibility and reaction time of swallowing as markers of dysphagia in parkinsonian syndromes

OBJECTIVE

To investigate reproducibility and reaction time of oropharyngeal swallowing in patients with Parkinson's disease (PD) and atypical parkinsonisms (APs).

METHODS

We enrolled 19 patients with PD, 30 with APs, and 20 healthy subjects. Presence and severity of dysphagia were assessed with clinical and fiberoptic endoscopic evaluations of swallowing. Reproducibility of the oral and pharyngeal phases of swallowing were respectively assessed by calculating the 'similarity index' of the electromyography activity of the submental/suprahyoid muscles and of the laryngeal-pharyngeal mechanogram during consecutive swallows. These were performed both 'on command' and spontaneously. The swallowing reaction time was also recorded.

RESULTS

Reproducibility of the oral phase of swallowing was reduced in patients with dysphagia, mainly when swallowing 'on command'. Swallowing reaction time was prolonged in dysphagic patients. These electrophysiological parameters did not vary among different parkinsonian syndromes and correlated with dysphagia severity.

CONCLUSIONS

Increased variability of oral swallowing automatisms and abnormal sensorimotor integration may be of relevance for the pathophysiology of dysphagia in parkinsonian syndromes.

SIGNIFICANCE

The electrophysiological assessment represents a valuable tool to investigate swallowing alterations in parkinsonian syndromes. It may also provide useful insights into clinical severity and pathophysiology of dysphagia, giving clues for the choice of the best therapeutic approach.

Model-Based and Model-Free Analyses of the Neural Correlates of Tongue Movements

The tongue performs movements in all directions to subserve its diverse functions in chewing, swallowing, and speech production. Using task-based functional MRI in a group of 17 healthy young participants, we studied (1) potential differences in the cerebral control of frontal (protrusion), horizontal (side to side), and vertical (elevation) tongue movements and (2) inter-individual differences in tongue motor control. To investigate differences between different tongue movements, we performed voxel-wise multiple linear regressions. To investigate inter-individual differences, we applied a novel approach, spatio-temporal filtering of independent components. For this approach, individual functional data were decomposed into spatially independent components and corresponding time courses using independent component analysis. A temporal filter (correlation with the expected brain response) was used to identify independent components time-locked to the tongue motor tasks. A spatial filter (cross-correlation with established neurofunctional systems) was used to identify brain activity not time-locked to the tasks. Our results confirm the importance of an extended bilateral cortical and subcortical network for the control of tongue movements. Frontal (protrusion) tongue movements, highly overlearned movements related to speech production, showed less activity in the frontal and parietal lobes compared to horizontal (side to side) and vertical (elevation) movements and greater activity in the left frontal and temporal lobes compared to vertical movements (cluster-forming threshold of Z > 3.1, cluster significance threshold of p < 0.01, corrected for multiple comparisons). The investigation of inter-individual differences revealed a component representing the tongue primary sensorimotor cortex time-locked to the task in all participants. Using the spatial filter, we found the default mode network in 16 of 17 participants, the left fronto-parietal network in 16, the right fronto-parietal network in 8, and the executive control network in four participants (Pearson's r > 0.4 between neurofunctional systems and individual components). These results demonstrate that spatio-temporal filtering of independent components allows to identify individual brain activity related to a specific task and also structured spatiotemporal processes representing known neurofunctional systems on an individual basis. This novel approach may be useful for the assessment of individual patients and results may be related to individual clinical, behavioral, and genetic information.

Lingual Pressure Dysfunction Contributes to Reduced Swallowing-Related Quality of Life in Parkinson's Disease

Purpose Dysphagia in Parkinson's disease (PD) is a major cause of depression and reduced quality of life (QOL). PD-related dysphagia often involves lingual dysfunction and weak pressure generation. The relation of disordered lingual pressure generation to swallowing-related QOL in persons with PD remains unknown. Method Twenty-four persons with idiopathic PD completed the Swallowing Quality of Life (SWAL-QOL) questionnaire and an evaluation of anterior and posterior tongue strength. Peak pressures were compared to age- and sex-matched controls. The magnitude of and latency to peak pressure were explored in relation to SWAL-QOL scores. Results Persons with PD exhibited significant anterior (p = .019) but not posterior (p = .081) lingual weakness compared to controls. Persons with PD and reduced anterior tongue strength (< 42 kPa) reported lower SWAL-QOL total (p = .043), extended eating durations (p = .025), and a reduced desire to eat (p = .020). Prolonged latency to peak anterior pressure in PD inversely correlated with SWAL-QOL total (r = -.750, p < .001) and served as a significant, independent predictor of 67% of the variance in SWAL-QOL total when controlling for age, sex, and disease stage. Conclusion Overall, SWAL-QOL scores declined in the presence of lingual pressure dysfunction. Lingual weakness and prolonged pressure building patterns secondary to PD, especially of the anterior tongue, may represent clinically relevant disruptions to mealtime behaviors that undermine swallowing-related QOL. These preliminary findings support further investigation of lingual pressure patterns in PD to help identify debilitating dysphagia and develop treatment strategies.

Dysphagia characteristics in Huntington's disease patients: insights from the Fiberoptic Endoscopic Evaluation of Swallowing and the Swallowing Disturbances Questionnaire

BACKGROUND

Huntington's disease (HD) is a neurodegenerative disease characterized by increasing dysphagia as the disease progresses. Specific characteristics of the HD dysphagia are not well defined.

OBJECTIVE

To characterize the swallowing disturbances of HD patients, to evaluate the feasibility of Fiberoptic Endoscopic Evaluation of Swallowing (FEES) in assessing dysphagia in HD patients, and to discern the relation between FEES findings and patients' self-report on dysphagia symptoms and swallowing related quality of life (SWAL-QOL).

METHOD

A retrospective case series in a tertiary referral center. All recruited HD patients underwent Bed Side Swallowing Evaluation (BSE), FEES, the Unified Huntington's Disease Rating Scale (UHDRS), and the Montreal Cognitive Assessment (MoCA). All completed the Swallowing Disturbances Questionnaire (SDQ) and the SWAL-QOL questionnaire.

RESULTS

Fourteen HD patients were recruited. All were able to complete the FEES study. The FEES demonstrated delayed swallowing reflex, solid food residues, and pre/post swallowing spillage in most patients (50%, 53.5%, 83.3%, and 87.5%, respectively). The mean SDQ score was 13.2. Significant correlations were found between the SWAL-QOL fear of eating score; the SDQ oral, pharyngeal, and total scores; and the FEES parameters of pureed and solid food bolus flow time. Significant correlations were also found between the total UHDRS score, the volitional cough score, and the SWAL-QOL disease burden score.

CONCLUSION

HD patients exhibit prominent unique oropharyngeal dysphagia features that may serve as a marker of disease progression. The FEES and the SDQ are valuable tools for detecting these features in HD patients with swallowing disturbance.

New application of dynamic magnetic resonance imaging for the assessment of deglutitive tongue movement

Background

Deglutitive motion of the tongue may function to maintain tooth position. However, the causation between abnormal patterns of orofacial muscle function and dental malocclusion remains unclear. To clarify the pathogenic mechanism of malocclusion, it is important to determine the relative positional relationship between the tongue tip and incisor edge or the dorsal tongue and palate during deglutition. Here, we assessed the utility of 3-T segmented cine-magnetic resonance (MR) imaging, combined with static MR images for hard tissue visualization, in assessing the relationship between the tongue and the surrounding tissues during deglutitive tongue movement.

Methods

Cine-MR images were acquired from three healthy female volunteers during deglutition who had no history of swallowing disorder or other chronic illness, normal alignment and occlusion, and a skeletal class I relationship. Three cine-MR images were taken during deglutition in accordance with an auditory cue for each volunteer. During static imaging, custom-made, contrast-medium-filled clear retainers were positioned in the mouth to allow visualization of the upper and lower incisors and hard palate boundaries. Static images were superimposed onto images of the three stages in deglutitive tongue movement, which were selected from a series of cine-MR images. These superimpositions were assessed five times by tracing cephalometric parameters to examine the reproducibility of the method.

Results

Traces varied little across repeated measurements, and all subjects had a similar pattern of dorsal tongue movement. Tongue-to-palate contact increased slightly during the first to second stage of swallowing and abruptly increased during the second to third stage, while the tongue tip position remained constant.

Conclusions

Segmented cine-MR imaging combined with static MR images is useful for assessing soft tissue motion during deglutition. This method is particularly useful in dentistry to evaluate the relationship between tongue function and maxillofacial morphology in terms of orthodontic treatment and orofacial myofunctional therapy, and for improving tongue movement during speech therapy.

Electronic supplementary material

The online version of this article (10.1186/s40510-018-0245-x) contains supplementary material, which is available to authorized users.

Home-Based Orolingual Exercise Improves the Coordination of Swallowing and Respiration in Early Parkinson Disease: A Quasi-Experimental Before-and-After Exercise Program Study

Introduction: The coordination of swallowing and respiration is important for safety swallowing without aspiration. This coordination was affected in Parkinson disease (PD). A noninvasive assessment tool was used to investigate the effect of an easy-to-perform and device-free home-based orolingual exercise (OLE) program on swallowing and respiration coordination in patients with early-stage PD.

Materials and Methods: This study had a quasi-experimental before-and-after exercise program design. Twenty six patients with early-stage PD who were aged 62.12 ± 8.52 years completed a 12-week home-based OLE program. A noninvasive assessment tool was used to evaluate swallowing and respiration. For each patient, we recorded and analyzed 15 swallows (3 repeats of 5 water boluses: 1, 3, 5, 10, and 20 mL) before and after the home-based OLE program. Oropharyngeal swallowing and its coordination with respiration were the outcome measures. The frequency of piecemeal deglutition, pre- and post-swallowing respiratory phase patterns, and parameters of oropharyngeal swallowing and respiratory signals (swallowing respiratory pause [SRP], onset latency [OL], total excursion time [TET], excursion time [ET], second deflexion, amplitude, and duration of submental sEMG activity, and amplitude of laryngeal excursion) were examined.

Results: The rate of piecemeal deglutition decreased significantly when swallowing 10- and 20-mL water boluses after the program. In the 1-mL water bolus swallowing trial, the rate of protective pre- and post-swallowing respiratory phase patterns was significantly higher after the program. For the parameters of oropharyngeal swallowing and respiratory signals, only the amplitude of laryngeal excursion was significantly lower after the program. Moreover, the volume of the water bolus significantly affected the SRP and duration of submental sEMG when patients swallowed three small water bolus volumes (1, 3, and 5 mL).

Conclusion: The home-based OLE program improved swallowing and its coordination with respiration in patients with early-stage PD, as revealed using a noninvasive method. This OLE program can serve as a home-based program to improve swallowing and respiration coordination in patients with early-stage PD.

Video-fluoroscopic swallowing study scale for predicting aspiration pneumonia in Parkinson's disease

Introduction

A number of video-fluoroscopic swallowing study (VFSS) abnormalities have been reported in patients with Parkinson’s disease (PD). However, the most crucial finding of subsequent aspiration pneumonia has not been validated fully. We conducted a retrospective and case-control study to determine the clinically significant VFSS findings in this population, and to propose a practical scale for predicting aspiration pneumonia in patients with PD.

Methods

We enrolled 184 PD patients who underwent VFSS because of suspected dysphagia. The patients who developed aspiration pneumonia within six months of the VFSS were assigned as cases and the patients without aspiration pneumonia at six months were designated as controls. Logistic regression analysis was performed to determine the prognostic VFSS features based on the data of swallowing 3 mL of jelly, which were used to make a PD VFSS scale (PDVFS). The validity of the new PDVFS was evaluated by ROC analysis. Additionally, we used the survival time analysis to compare time to death between groups, stratified by the PDVFS score.

Results

Twenty-five patients developed aspiration pneumonia. Among the previously-proposed VFSS features, mastication, lingual motility prior to transfer, aspiration, and total swallow time were identified as significant prognostic factors. We combined these factors to form the PDVFS. The PDVFS score ranges from 0 to 12, with 12 being the worst. ROC analysis revealed 92% sensitivity and 82% specificity at a cutoff point of 3. The higher PDVFS group showed shorter time-to-death than the lower PDVFS group (log rank P = 0.001).

Conclusion

Our newly developed VFSS severity scale (based on jelly swallowing) for patients with PD was easy to rate and could predict subsequent aspiration pneumonia and poor prognosis in patients with PD.

Age-Related Variability in Tongue Pressure Patterns for Maximum Isometric and Saliva Swallowing Tasks

PURPOSE

The ability to generate tongue pressure plays a major role in bolus transport in swallowing. In studies of motor control, stability or variability of movement is a feature that changes with age, disease, task complexity, and perturbation. In this study, we explored whether age and tongue strength influence the stability of the tongue pressure generation pattern during isometric and swallowing tasks in healthy volunteers.

METHOD

Tongue pressure data, collected using the Iowa Oral Performance Instrument, were analyzed from 84 participants in sex-balanced and decade age-group strata. Tasks included maximum anterior and posterior isometric pressures and regular-effort saliva swallows. The cyclic spatiotemporal index (cSTI) was used to capture stability (vs. variability) in patterns of pressure generation. Mixed-model repeated measures analyses of covariance were performed separately for each task (anterior and posterior isometric pressures, saliva swallows) with between-participant factors of age group and sex, a within-participant factor of task repetition, and a continuous covariate of tongue strength.

RESULTS

Neither age group nor sex effects were found. There was no significant relationship between tongue strength and the cSTI on the anterior isometric tongue pressure task (r = -.11). For the posterior isometric tongue pressure task, a significant negative correlation (r = -.395) was found between tongue strength and the cSTI. The opposite pattern of a significant positive correlation (r = .29) between tongue strength and the cSTI was seen for the saliva swallow task.

CONCLUSIONS

Tongue pressure generation patterns appear highly stable across repeated maximum isometric and saliva swallow tasks, despite advancing age. Greater pattern variability is seen with weaker posterior isometric pressures. Overall, saliva swallows had the lowest pressure amplitudes and highest pressure pattern variability as measured by the cSTI.

Videofluoroscopic Predictors of Penetration-Aspiration in Parkinson's Disease Patients

Parkinson's disease (PD) patients show a high prevalence of swallowing disorders and tracheal aspiration of food. The videofluoroscopic study of swallowing (VFSS) allows clinicians to visualize the visuoperceptual and temporal parameters associated with swallowing disorders in an attempt to predict aspiration risk. However, this subject remains understudied in PD populations. Our aim was to identify the predictors of penetration-aspiration in PD patients using the VFSS. Consecutive patients were evaluated using VFSS with different consistencies and volumes of food. A speech-language pathologist measured the type of intra-oral bolus organization, loss of bolus control, bolus location at the initiation of the pharyngeal swallow, the presence of multiple swallows, piecemeal deglutition, bolus residue in the pharyngeal recesses and temporal measures. Scores ≥3 on the penetration-aspiration scale (PAS) indicated the occurrence of penetration-aspiration. Using logistic marginal regression, we found that residue in the vallecula, residue in the upper esophageal sphincter and piecemeal deglutition were associated with penetration-aspiration (odds ratio (OR) = 4.09, 2.87 and 3.83; P = 0.0040, 0.0071 and 0.0009, respectively). Penetration/aspiration occurred only with fluids (both of thin and thick consistency), and no significant differences were observed between fluid types or food volumes. The mechanisms underlying dysphagia and penetration/aspiration in PD patients and indications for further studies are discussed.

Swallowing disorders in Parkinson's disease: impact of lingual pumping

BACKGROUND

Lingual pumping (LP) is a repetitive, involuntary, anteroposterior movement of the tongue on the soft palate that is executed prior to transferring the food bolus to the pharynx, but we also observed LP when multiple swallows were taken. LP may be associated with rigidity and bradykinesia in patients with Parkinson's disease (PD). This phenomenon tends to be more prevalent in dysphagic PD patients, and its impact on swallowing dynamics remains poorly understood.

OBJECTIVE

To evaluate how LP interferes with the oral and pharyngeal phases of the swallowing of foods of different consistencies and volumes.

METHODS

We used videofluoroscopy to study the swallowing of 69 PD patients performing 10 swallows of barium mixed with foods of different consistencies and volumes.

RESULTS

LP was associated with the unstable intra-oral organization of the bolus, the loss of bolus control, the pharyngeal retention of food and food entering the airway. This abnormal movement was also associated with a shorter oral transit time and was found to be more prevalent with food of thicker consistencies.

CONCLUSIONS

LP is associated with swallowing incoordination and with food entering the airway. Preventive measures to minimise the pulmonary or nutritional consequences of this behaviour are necessary.

Multiple factors are involved in the dysarthria associated with Parkinson's disease: a review with implications for clinical practice and research

PURPOSE

Motor speech abnormalities are highly common and debilitating in individuals with idiopathic Parkinson's disease (IPD). These abnormalities, collectively termed hypokinetic dysarthria (HKD), have been traditionally attributed to hypokinesia and bradykinesia secondary to muscle rigidity and dopamine deficits. However, the role of rigidity and dopamine in the development of HKD is far from clear. The purpose of the present study was to offer an alternative view of the factors underlying HKD.

METHOD

The authors conducted an extensive, but not exhaustive, review of the literature to examine the evidence for the traditional view versus the alternative view.

RESULTS

The review suggests that HKD is a highly complex and variable phenomenon including multiple factors, such as scaling and maintaining movement amplitude and effort; preplanning and initiation of movements; internal cueing; sensory and temporal processing; automaticity; emotive vocalization; and attention to action (vocal vigilance). Although not part of the dysarthria, nonmotor factors, such as depression, aging, and cognitive-linguistic abnormalities, are likely to contribute to the overall speech symptomatology associated with IPD.

CONCLUSION

These findings have important implications for clinical practice and research.

Early identification and treatment of communication and swallowing deficits in Parkinson disease

Parkinson disease (PD) is a complex, progressive, neurodegenerative disorder that leads to a wide range of deficits including fine and gross sensorimotor impairment, autonomic dysfunction, mood disorders, and cognitive decline. Traditionally, the focus for diagnosis and treatment has been on sensorimotor impairment related to dopamine depletion. It is now widely recognized, however, that PD-related pathology affects multiple central nervous system neurotransmitters and pathways. Communication and swallowing functions can be impaired even in the early stages, significantly affecting health and quality of life. The purpose of this article is to review the literature on early intervention for communication and swallowing impairment in PD. Overarching themes were that (1) studies and interpretation of data from studies in early PD are limited; (2) best therapy practices have not been established, in part due to the heterogeneous nature of PD; and (3) as communication and swallowing problems are pervasive in PD, further treatment research is essential.