Research-based Updates in Swallowing and Communication Dysfunction in Parkinson Disease: Implications for Evaluation and Management

Psychosocial Experiences Associated with Dysphagia and Relevant Clinical Implications Among Adults with Parkinson Disease

Although the psychosocial sequelae of living with dysphagia secondary to Parkinson disease (PD) are described in the literature as challenging, there has been little focus on using this information to influence the design of dysphagia treatment. A more nuanced understanding of the psychosocial experiences of this population may assist clinicians in providing a patient-centered approach to care. Our study was designed to gather insight into the common psychosocial experiences associated with dysphagia in the context of PD. A semi-structured interview consisting of open- and closed items was conducted with 25 individuals from regions across the country with self-reported oropharyngeal dysphagia secondary to PD. Questions were developed using comprehensive stress and coping frameworks that emphasized psychosocial predictors of specific affective reactions (e.g., grief, anxiety, depression), including self-evaluation (e.g., self-identity), coping strategies, social support, personal expectations (including perceived control over symptoms and prognosis), positive experiences, and perceptions of personal growth. Interview responses were subjected to a qualitative analysis and revealed three dominant themes: (1) Recalibration of a PD Diagnosis, (2) Vigilant Caution to Swallowing, and (3) Grieving the Loss of the Communal Meal. Using these data interpretations, we discuss three concepts for speech-language pathologists working with individuals with dysphagia and PD to consider during clinical interactions; these are reframing swallowing vigilance to engagement with mindful eating, using biofeedback to align patient perceptions and swallow physiology, and understanding the consequences of loss (of their former swallowing ability) through grief and growth reactions.

The Effect of Oropharyngeal Resting Tremor on Swallowing Function in a Clinical Cohort of People with Parkinson's Disease

Parkinson's Disease (PD) is a progressive neurodegenerative disease, with hallmark symptomology typically consisting of tremor, bradykinesia, and rigidity. Though the classic "pill-rolling" rest tremor in the hand or upper limb are often the most salient, it can occur throughout the body including the lower limbs, jaw, face, or tongue. There have been investigations into other motor related phenomena potentially affecting swallow function in PwPD previously. However, there have been no investigations of how oropharyngeal resting tremor in structures such as the tongue or larynx explicitly affects swallowing physiology. A retrospective analysis of previously conducted VFSS on 34 patients diagnosed with idiopathic PD (IPD) was performed to examine how individuals that displayed resting tremor during VFSS (Tremor +) and those who did not (Tremor-) differ in swallowing function. Measures of swallowing function including timing intervals of key swallow events, post-swallow residue, and penetration-aspiration scale (PAS) scores were recorded, and key demographic information including time since diagnosis and medication status were extracted from the medical records available. Multivariate models were used to identify differences between tremor groups for timing intervals and post-swallow residue, and chi-squares were computed for differences in PAS score distribution by group and bolus. Sixty-eight percent (23/34) of this sample displayed oropharyngeal resting tremor in at least one structure during VFSS. There were no instances of other tremor types observed in this sample. All participants were taking medication to manage PD symptomology. Significant effects of tremor group were observed for swallow timing intervals related to airway closure (p < 0.001), post-swallow residue (p < 0.05), and swallow safety at the bolus level in the Tremor + group (p < 0.001). These results suggest that PwPD who present with resting tremor in oropharyngeal structures may manifest with different variations in swallowing physiology, including altered timings of swallow events, increased pharyngeal residue, and greater associations of airway invasion with thinner and larger volume boluses. This study highlights the need for substantially more research into how motor fluctuations and phenotypes of PwPD contribute to alterations in swallowing function.

Dysphagia in Parkinson Disease: Part I - Pathophysiology and Diagnostic Practices

Purpose of Review

Dysphagia affects the majority of individuals with Parkinson disease (PD) and is not typically diagnosed until later in disease progression. This review will cover the current understanding of PD pathophysiology, and provides an overview of dysphagia in PD including diagnostic practices, gaps in knowledge, and future directions.

Recent Findings

Many non-motor and other motor signs of PD appear in the prodrome prior to the manifestation of hall- mark signs and diagnosis. While dysphagia often presents already in the prodrome, it is not routinely addressed in standard neurology examinations.

Summary

Dysphagia in PD can result in compromised efficiency and safety of swallowing, which significantly contributes to malnutrition and dehydration, decrease quality of life, and increase mortality. The heterogeneous clinical presentation of PD complicates diagnostic procedures which often leads to delayed treatment. Research has advanced our knowledge of mechanisms underlying PD, but dysphagia is still largely understudied, especially in the prodromal stage.

Dysphagia in Parkinson Disease: Part II-Current Treatment Options and Insights from Animal Research

Purpose of Review

Dysphagia is highly prevalent in Parkinson disease (PD) but is not typically identified nor treated until later in the disease process. This review summarizes current pharmacological, surgical, and behavioral treatments for PD-associated dysphagia and contributions from translational animal research.

Recent Findings

Swallowing is a complex physiologic process controlled by multiple brain regions and neurotransmitter systems. As such, interventions that target nigrostriatal dopamine dysfunction have limited or detrimental effects on swallowing outcomes. Behavioral interventions can help target PD-associated dysphagia in mid-to-late stages. Animal research is necessary to refine treatments and useful in studying prodromal dysphagia.

Summary

Dysphagia is an early, common, and debilitating sign of PD. Current pharmacological and surgical interventions are not effective in ameliorating swallowing dysfunction; behavioral intervention remains the most effective approach for dysphagia treatment. Animal research has advanced our understanding of mechanisms underlying PD and PD-associated dysphagia, and continues to show translational promise for the study of dysphagia treatment options.

Clear Speech Variants: An Investigation of Intelligibility and Speaker Effort in Speakers With Parkinson's Disease

PURPOSE

This study investigated the effects of three clear speech variants on sentence intelligibility and speaking effort for speakers with Parkinson's disease (PD) and age- and sex-matched neurologically healthy controls.

METHOD

Fourteen speakers with PD and 14 neurologically healthy speakers participated. Each speaker was recorded reading 18 sentences from the Speech Intelligibility Test in their habitual speaking style and for three clear speech variants: clear (SC; given instructions to speak clearly), hearing impaired (HI; given instructions to speak with someone with a hearing impairment), and overenunciate (OE; given instructions to overenunciate each word). Speakers rated the amount of physical and mental effort exerted during each speaking condition using visual analog scales (averaged to yield a metric of overall speaking effort). Sentence productions were orthographically transcribed by 50 naive listeners. Linear mixed-effects models were used to compare intelligibility and speaking effort across the clear speech variants.

RESULTS

Intelligibility was reduced for the PD group in comparison to the control group only in the habitual condition. All clear speech variants significantly improved intelligibility above habitual levels for the PD group, with OE maximizing intelligibility, followed by the SC and HI conditions. Both groups rated speaking effort to be significantly higher for both the OE and HI conditions versus the SC and habitual conditions.

DISCUSSION

For speakers with PD, all clear speech variants increased intelligibility to a level comparable to that of healthy controls. All clear speech variants were also associated with higher levels of speaking effort than habitual speech for the speakers with PD. Clinically, findings suggest that clear speech training programs consider using the instruction "overenunciate" for maximizing intelligibility. Future research is needed to identify if high levels of speaking effort elicited by the clear speech variants affect long-term sustainability of the intelligibility benefit.

On the Relationship between Speech Intelligibility and Fluency Indicators among English-Speaking Individuals with Parkinson’s Diseases

The purpose of the study is to investigate how much of variance in Parkinson's Disease (PD) individuals' speech intelligibility could be predicted by seven speech fluency indicators (i.e., repetition, omission, distortion, correction, unfilled pauses, filled pauses, and speaking rate). Speech data were retrieved from a database containing a reading task produced by a group of 16 English-speaking individuals with PD (Jaeger, Trivedi & Stadtchnitzer, 2019). The results from a multiple regression indicated that an addition of 54% of variance in the speech intelligibility scores among individuals with PD could be accounted for after the speakers' PD severity level measured based on Hoehn and Yahr's (1967) disease stage was included as a covariate. In addition, omission and correction were the two fluency indicators that contributed to the general intelligibility score in a statistically significant way. Specifically, for every one-unit gain in the number of correction and omission, speech intelligibility scores would decline by 0.687 and 0.131 point (out of a 7-point scale), respectively. The current study hence supported Magee, Copland, and Vogel's (2019) view that the language production abilities and quantified dysarthria measures among individuals with PD should be explored together. Additionally, the clinical implications based on the current findings were discussed.

Voice handicap Index in Parkinson's patients: Subthalamic versus globus pallidus deep brain stimulation

PURPOSE

Subthalamic nucleus (STN) and globus pallidus interna (GPI) are the two most common sites for deep brain stimulation (DBS) in people with Parkinson's disease (PWP). Voice impairments are a common symptom of Parkinson's disease and information about voice outcomes with DBS is limited. Most studies in speech-language pathology have focused on STN-DBS and few have examined the effects of GPI-DBS. This was an initial effort to examine the impact of DBS location on Vocal Handicap Index (VHI) scores, which assess the impact of a voice disorder on an individual.

METHOD

Twenty-four gender-matched PWP (12 STN-DBS and 12 GPI-DBS) completed the VHI post-DBS implantation. Two-tailed independent samples t-tests were used to compare each VHI scale score (physical, functional, emotional, total) and patient factors between the two groups.

RESULTS

No significant differences in total or subscale VHI scores were identified between the two DBS groups. A trend toward greater impairment in PWP with GPI-DBS was noted. An association between higher VHI scores and DBS settings was found.

CONCLUSIONS

Studies directly comparing speech outcomes for different DBS targets are lacking. The current findings provide new insights concerning voice outcomes following DBS by adding to the limited literature directly comparing speech outcomes in multiple DBS targets. Limitations and directions for future research are discussed.

Speech dysfunction, cognition, and Parkinson's disease

Communication difficulties are a ubiquitous symptom of Parkinson's disease and include changes to both motor speech and language systems. Communication challenges are a significant driver of lower quality of life. They are associated with decreased communication participation, social withdrawal, and increased risks for social isolation and stigmatization in persons with Parkinson's disease. Recent theoretical advances and experimental evidence underscore the intersection of cognition and motor processes in speech production and their impact on spoken language. This chapter overviews a growing evidence base demonstrating that cognitive impairments interact with motor changes in Parkinson's disease to negatively affect communication abilities in myriad ways, at all stages of the disease, both in the absence and presence of dementia. The chapter highlights common PD interventions (pharmacological, surgical, and non-pharmacological) and how cognitive influences on speech production outcomes are considered in each.

Feedback and Feedforward Auditory-Motor Processes for Voice and Articulation in Parkinson's Disease

PURPOSE

Unexpected and sustained manipulations of auditory feedback during speech production result in "reflexive" and "adaptive" responses, which can shed light on feedback and feedforward auditory-motor control processes, respectively. Persons with Parkinson's disease (PwPD) have shown aberrant reflexive and adaptive responses, but responses appear to differ for control of vocal and articulatory features. However, these responses have not been examined for both voice and articulation in the same speakers and with respect to auditory acuity and functional speech outcomes (speech intelligibility and naturalness).

METHOD

Here, 28 PwPD on their typical dopaminergic medication schedule and 28 age-, sex-, and hearing-matched controls completed tasks yielding reflexive and adaptive responses as well as auditory acuity for both vocal and articulatory features.

RESULTS

No group differences were found for any measures of auditory-motor control, conflicting with prior findings in PwPD while off medication. Auditory-motor measures were also compared with listener ratings of speech function: first formant frequency acuity was related to speech intelligibility, whereas adaptive responses to vocal fundamental frequency manipulations were related to speech naturalness.

CONCLUSIONS

These results support that auditory-motor processes for both voice and articulatory features are intact for PwPD receiving medication. This work is also the first to suggest associations between measures of auditory-motor control and speech intelligibility and naturalness.

A multinational consensus on dysphagia in Parkinson's disease: screening, diagnosis and prognostic value

Background

Parkinson’s disease (PD) is a neurodegenerative disorder characterized by a combination of motor and non-motor dysfunction. Dysphagia is a common symptom in PD, though it is still too frequently underdiagnosed. Consensus is lacking on screening, diagnosis, and prognosis of dysphagia in PD.

Objective

To systematically review the literature and to define consensus statements on the screening and the diagnosis of dysphagia in PD, as well as on the impact of dysphagia on the prognosis and quality of life (QoL) of PD patients.

Methods

A multinational group of experts in the field of neurogenic dysphagia and/or PD conducted a systematic revision of the literature published since January 1990 to February 2021 and reported the results according to PRISMA guidelines. The output of the research was then analyzed and discussed in a consensus conference convened in Pavia, Italy, where the consensus statements were drafted. The final version of statements was subsequently achieved by e-mail consensus.

Results

Eighty-five papers were used to inform the Panel’s statements even though most of them were of Class IV quality. The statements tackled four main areas: (1) screening of dysphagia: timing and tools; (2) diagnosis of dysphagia: clinical and instrumental detection, severity assessment; (3) dysphagia and QoL: impact and assessment; (4) prognostic value of dysphagia; impact on the outcome and role of associated conditions.

Conclusions

The statements elaborated by the Consensus Panel provide a framework to guide the neurologist in the timely detection and accurate diagnosis of dysphagia in PD.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00415-021-10739-8.

The Frequency of Atypical and Extreme Values for Pharyngeal Phase Swallowing Measures in Mild Parkinson Disease Compared to Healthy Aging

Purpose Dysphagia is thought to be prevalent and a leading cause of morbidity and mortality in people with Parkinson disease (PwPD). The aim of this study was to compare the frequencies of atypical and extreme values for measures of swallowing physiology in PwPD and in an age- and sex-matched cohort of healthy adults. Atypical and extreme values were defined, respectively, as values falling in the 25% and 5% tails of the reference distribution for healthy adults under age 60 years. Method A standard videofluoroscopy (VF) protocol was performed in 17 adults with mild PD and 17 age- and sex-matched healthy adults using 20% w/v liquid barium ranging from thin to extremely thick consistency. Blinded VF analysis was performed according to the Analysis of Swallowing Physiology: Events, Kinematics and Timing Method. Frequencies for atypical and extreme values were tabulated by cohort and compared using odds ratios. Results Increased frequencies of atypical values (> 25%) were seen in the PwPD for prolonged swallow reaction time, prolonged time-to-laryngeal-vestibule-closure (LVC), and poor pharyngeal constriction. However, these findings were also observed in the healthy controls. The PwPD showed significantly higher odds of atypical values for narrow upper esophageal sphincter (UES) diameter on thin liquids, a short hyoid-burst-to-UES-opening interval on extremely thick liquids, and prolonged time-to-LVC, LVC duration, and UES opening duration on multiple consistencies. The frequencies of extreme values failed to show any significant cohort differences for any parameter. Conclusions In this study, a group of people with mild PD did not show clear evidence of swallowing impairments distinct from the changes seen in a healthy age-matched control group when odds ratios were used to compare the frequencies of atypical values between PwPD and the control group; only a few parameters showed significant differences. These were findings of significantly higher frequencies in PwPD of prolonged LVC and UES opening duration. Supplemental Material https://doi.org/10.23641/asha.15032241.

Self-perceptions of speech, voice, and swallowing in motor phenotypes of Parkinson's disease

INTRODUCTION

The ability of people with Parkinson's Disease (PWPD) to perceive and identify impairments related to communication and swallowing is often impaired. This impairment prolongs the time to diagnosis of dysphonia and dysphagia, and can delay implementation of speech or swallowing therapy. We have limited knowledge of how different motor phenotypes of PD impact speech, voice and swallowing, nor how PWPD perceive these impacts. The purpose of this study was to identify how perceptions of speech and voice impairments predict dysphagia in PD, and how those perceptions differ between motor phenotypes.

METHODS

38 PWPD completed clinical surveys including V-RQOL, DHI, and a speech, voice, and swallow symptom questionnaire. Participants were categorized as either tremor dominant (TD) or non-tremor dominant (NTD) phenotypes. Multiple regression and MANOVA were utilized to identify predictors of dysphagia perceptions, and for differentiating between motor phenotype based on perceptual severity.

RESULTS

Perceptions of speech and voice impairment predicted perceptions of swallow impairment regardless of phenotype (p < .05, CI = 0.08-0.77). NTD participants reported significantly more communication and swallowing impairments than TD (p < .05) and perceived communication impairment severity was the strongest predictor of group classification (OR = 0.50). The survey battery displayed a robust discriminatory ability between phenotype (AUC = 0.87, CI = 0.76-0.98).

CONCLUSION

The use of a noninvasive and cost-efficient survey battery may be useful in predicting patient perceived swallow impairment in PWPD. Speech, voice, and swallow impairments based on survey responses were found to differ between motor phenotypes.

Cross-cultural adaptation and validation of the Swallowing Disturbance Questionnaire and the Sialorrhea Clinical Scale in Portuguese patients with Parkinson's disease

INTRODUCTION

To date, no valid outcome measure has been developed in European Portuguese (EP) to evaluate the Parkinsons' Disease (PD) patients' (PwP) reports regarding their swallowing disturbances.

OBJECTIVES

The aim of this study was to translate and cross-culturally adapt the Swallowing Disturbance Questionnaire (SDQ) and the Sialorrhea Clinical Scale for PD (SCS-PD) into EP and to determine its clinimetric properties in PwP.

MATERIALS AND METHODS

The original English SDQ and SCS-PD versions were cross-culturally adapted following recommendations established in international guidelines. The validation process involved 75 PwP and 65 healthy sex- and age-matched participants.

RESULTS

The EP versions of the SDQ and SCS-PD are equivalent to the original versions (content, depth, and scoring). Statistical analyses for the SDQ tool revealed good feasibility (missing data <5%), acceptability (no floor or ceiling effects), excellent internal consistency (Cronbach´s α = 0.95), good construct validity (78.5% revealed large to moderate loadings), moderate convergent validity (r = 0.60), good divergent validity (r = 0.40), good known-groups validity (p-value < .05) and a fair sensitivity and specificity (AUC = 0.700). Statistical analyses for the SCS-PD tool shows good feasibility, reasonable acceptability (floor effect), good internal consistency (Cronbach´s α = 0.85), good construct validity (85.7% showed between large to moderate loadings), good convergent validity (r = 0.78), good divergent validity (r = 0.39), good known groups validity (p-value < .05) and a fair sensitivity and specificity (AUC = 0.704).

CONCLUSIONS

The EP versions of the SDQ and SCS-PD maintained the characteristics of the original versions and therefore consistent tools to be used in PwP.