Emotional Sentence Processing in Parkinson's Disease.

PURPOSE: Emotional processing allows us to predict our own and others' behavior, communicate our wants and needs, and understand those of others. Thus, deficits in emotional processing can negatively impact one's quality of life. While changes in emotional processing across several domains (e.g., prosody, faces) in Parkinson's disease (PD) are widely accepted, there is a dearth of literature, with equivocal results, regarding how emotional language processing is affected by PD. This study investigated emotional sentence processing in this population. METHOD: Eighteen persons with PD and 22 healthy adults (HAs) completed a language task in which they rated sentences on their pleasantness (valence), and a battery of cognitive tasks and mood measures that were examined as factors influencing performance. As an interaction between emotionality and concreteness during processing has been indicated in prior research, concreteness of sentence stimuli was also manipulated. RESULTS: Individuals with PD rated negatively valenced sentences as less negative and positively-valenced sentences as less positive than HAs. The PD group also demonstrated a reduced overall range of valence rating scores. Sentence concreteness did not influence ratings. Results for positive sentences could be explained by individual differences in working memory (WM), whereas individual differences in WM, depression, and group explained differences in ratings to negative sentences. CONCLUSIONS: Our study provides one of few accounts of emotional language processing deficits in PD, particularly beyond the word level. Individuals with PD may experience difficulty perceiving and assessing the intensity of the emotional content of language, and deficits may disproportionately impact processing of sentences about negative situations. SUPPLEMENTAL MATERIAL: https://doi.org/10.23641/asha.21313713.

Global Coherence and Cognition in Parkinson's Disease.

PURPOSE: This study compared global coherence (GC) in individuals with Parkinson's disease (PD) to a healthy older adult (HOA) group during single (sitting) and dual (stationary cycling) tasks. Additionally, it explored the relationship between GC and cognition in PD. METHOD: Thirty-seven individuals with PD and 19 HOAs participated in the prospective, cross-sectional study. Participants completed discourse monologues elicited using published prompts while seated and while pedaling a stationary bicycle. Four rating levels of GC were analyzed (GC1 = no relationship to the topic, GC2 = remote relationship, GC3 = conditional relationship, and GC4 = complete relationship) using a published protocol with good interrater reliability and test-retest stability. Participants completed a battery of cognitive tasks, from which four latent factors were extracted: processing speed, working memory, inhibition, and updating. RESULTS: Linear mixed modeling identified significant effects of GC level and GC level interactions with group, processing speed, and inhibition. The Group × GC Level interaction reflected that the PD group had a higher proportion of GC2 and GC1 utterances and fewer GC4 utterances than the HOA group. No differences between single and dual task conditions were found. Faster speed of processing predicted more GC4 utterances, whereas slower speed of processing predicted more G1 utterances. Better inhibition predicted fewer GC2 utterances. Group also predicted GC4 and GC2 proportions. CONCLUSIONS: Individuals with PD experienced greater difficulties with GC than HOAs. Processing speed and inhibition contributed significantly to GC across groups. Analysis of GC should be considered an informative addition to assessment of communicative effectiveness in PD. SUPPLEMENTAL MATERIAL: https://doi.org/10.23641/asha.20416056.

Higher relative effort of the knee relates to faster adaptation in older adults at risk for mobility disability.

Gait adaptation is crucial for adults at risk for mobility disability, and executive function and physical function may be important for adaptation performance. Gait adaptation can be measured using a treadmill with two belts, known as a split-belt treadmill. Increasing evidence supports that gait adaptability, executive function, and physical function are interrelated in older adults. The purpose of this study was to determine if: a) executive function and measures of relative effort of the ankle and knee relate to split-belt treadmill adaptation; b) older adults classified as fast adapters display differences in relative effort, executive function, and propulsive impulse (push-off) compared to slow adapters; and c) spatial and temporal control differ between individuals with faster rate of adaptation compared to those with slower rates of adaptation. Greater effort of the knee on the slow belt was related to faster early adaptation (r = 0.650, p = 0.005) indicating its importance for adapting quickly to the perturbation. We did not observe a relationship between cognitive tests and adaptation performance. We did not detect any statistical differences in cognitive tests performance, push-off, spatial or temporal control between fast adapters compared to slow adapters. Our results suggest that in older adults at risk for mobility disability, higher effort at the knee is important for early split-belt adaptation.

The relationship between trained ratings and untrained listeners' judgments of global coherence in extended monologues.

BACKGROUND: Global coherence rating scales have been used by a number of researchers to examine spoken discourse in populations with and without acquired neurogenic communication disorders. The 4-point global coherence (GC) scale in the current study has demonstrated reliability and convergent validity. However, we have not yet established how a global coherence rating corresponds to functional communication. AIMS: The current study explores the clinical meaningfulness of the 4-point GC rating scale. Survey questions and ratings were developed to examine discourse quality and functional coherence as perceived by untrained listeners. Ratings by untrained listeners were compared to trained discourse ratings using the established 4-point GC scale. METHODS: Twelve discourse samples, scored by a trained rater, were selected for the current study from a previously collected set of discourse transcripts. Transcripts were extended monologues in response to one of four possible open-ended questions that were re-recorded by the trained rater to remove any distracting features of the original recordings, such as articulatory errors. Twenty-four untrained listeners rated the discourse samples using a short questionnaire that included questions for each sample about: topic maintenance, inclusion of unnecessary information, and the listener level of interest and attention. Questions for untrained listeners were based on operational definitions of global coherence and discourse quality respectively. These untrained ratings were compared to trained ratings of global coherence. Outcome measures were compared using non-parametric tests and a Spearman Rank Order test was also used to examine relationships among variables. OUTCOMES AND RESULTS: Untrained listeners' ratings for topic maintenance and inclusion of unnecessary information were significantly different between trained low, medium, and high global coherence ratings. Topic maintenance and inclusion of unnecessary information were also both significantly correlated with global coherence. Untrained listeners' ratings of their level of interest and attention for a sample were significantly different between trained medium-high and low-high global coherence ratings. Interest and attention ratings were also significantly correlated with ratings of global coherence. CONCLUSIONS: Untrained raters did differentiate between levels of global coherence using ratings of topic maintenance, inclusion of unnecessary information, and their level of attention and interest. Global coherence was also significantly correlated with the untrained ratings. These findings provide preliminary external validity for the global coherence scale and support its clinical utility.

Effects of a Cycling Dual Task on Emotional Word Choice in Parkinson's Disease.

Purpose Individuals with Parkinson's disease (PD) demonstrate language- and emotion-related impairments; however, emotional language production has received little attention within the literature despite the fact that deficits could significantly impact one's daily interactions with loved ones and others. Multitasking (i.e., dual tasking), specifically while completing language tasks, is a common everyday occurrence and typically impacts performance on 1 or both tasks. This study compared emotional word use during discourse production in individuals with PD and healthy older adults (HOAs) under single- and dual-task conditions. Method Participants completed a discourse task while sitting in a quiet room and while stationary cycling. Discourse output was analyzed along several emotional and intellectual language dimensions obtained from the Linguistic Inquiry and Word Count program (Pennebaker, Booth, & Francis, 2007 ). Results Groups did not differ on any outcome measure in the single-task condition. However, HOAs produced a higher percentage of words associated with affective processes and positive emotion while completing the dual-task condition, whereas the PD group exhibited a decrease in production of these words. Compared to the single-task condition, during cycling, individuals with PD also produced a lower percentage of inhibition-related words. Conclusions These results suggest that cycling, like other types of exercise, improves mood as manifested in discourse word choice in HOAs; however, it may lead to reduced use of emotional words in individuals with PD. Expressing emotion may also be more difficult in those with PD than in HOAs and, therefore, easily disrupted in distracting circumstances.

Older women take shorter steps during backwards walking and obstacle crossing.

BACKGROUND: Community ambulation requires the ability to adapt walking patterns to task demands. For example, complex walking tasks, such as obstacle crossing (OBS) and backwards walking (BW), require modification of gait kinematics to complete the task, maintain stability and prevent falling. More women than men fall each year, but few studies have investigated gender differences in performance of adaptive walking tasks. OBJECTIVE: The purpose of this study was to determine gender differences in two common adaptive tasks. METHODS: Walking performance was assessed from 54 age and gender matched participants (72 ±â€¯5 yrs.) while they completed forward walking (FW), OBS and BW. Gait outcomes and the distance of the lead foot and the trail foot from the obstacle were normalized by leg length and assessed using multivariate analysis of variance. Additionally, performance in a battery of clinical physical and cognitive measures as well as self-reported activity levels were associated with adaptive gait behavior. RESULTS: Gait speed and step width were not different between genders in any walking task. Compared to FW and OBS, women only decreased step length in BW, resulting in significantly shorter step lengths than men in OBS (p = 0.02) and BW (p = 0.04), a conservative walking strategy. Women crossed the obstacle in a manner that may limit recovery steps in case of a trip: stepping closer to the obstacle during approach without increasing trail toe-clearance. The Timed Up and Go mobility test, Short Physical Performance Battery, and Trail Making Test of processing speed and executive function were associated with gender differences in adaptive gait patterns. CONCLUSION: The findings revealed that older adult women adapt walking in a way that might predispose them to tripping or falling (i.e. shorter steps and closer obstacle approach). Gender differences in adaptive walking are related to functional test performance and processing speed. Clinicians should consider targeting step length during adaptive walking tasks in women that may be at risk of mobility impairments.

Rapid Serial Visual Presentation Interacts with Ambiguity During Sentence Comprehension.

Conventional opinion about using Rapid Serial Visual Presentation (RSVP) for examining sentence comprehension maintains that RSVP taxes working memory (WM), which probably affects sentence processing. However, most RSVP studies only infer the involvement of WM. Other cognitive resources, such as cognitive control or vocabulary may also impact sentence comprehension and interact with RSVP. Further, sentence ambiguity is predicted to interact with RSVP and cognitive resources to impact sentence comprehension. To test these relationships, participants read ambiguous and unambiguous sentences using RSVP and Whole-Sentence presentation, followed by comprehension questions that were targeted to the ambiguous region of the sentences. Presentation type and ambiguity interacted to affect RT such that the effect of RSVP was exaggerated for ambiguous sentences. RT effects were moderated by WM and vocabulary. WM and cognitive control affected accuracy. Findings are discussed in light of depth of processing and the impact of cognitive resources on sentence comprehension.

Novel associative processing and aging: effect on creative production.

Creative production has been reported to decline with age. This study investigated age-related differences in creative verbal production. Participants were 30 younger and 30 older adults. Study testing included language and cognitive assessments and the experimental task wherein participants created short stories incorporating words that are not commonly related, semantically or associatively. The resulting stories were rated by independent blinded judges for originality, cohesion, appropriateness, and organization. Younger adults' stories were rated as being significantly more original and more appropriate. Integrating unrelated words to create original stories requires activating widely distributed lexical-semantic networks to develop novel associations. Potential decreased neural network connectivity due to white matter degradation, commonly seen in normal aging, as well as decrements in front-executive disengagement may have affected older adults' performance on this story creation task. Future research using neuroimaging may elucidate possible neuroanatomic correlates of age-related changes in associative creative production..

A meta-analysis: Parkinson's disease and dual-task walking.

A growing body of literature has reported the effects of dual tasks on gait performance in people with Parkinson's disease (PD). The purpose of this meta-analysis was to synthesize the existing literature and quantify the overall influence of dual tasks on gait performance in PD. A thorough literature search was conducted, and 19 studies met the stringent inclusion criteria. Two moderator variable analyses examined the dual-task effect by: (a) mean single-task gait speed for each study (≥1.1 m/s or < 1.1 m/s), and (b) the type of dual task (arithmetic, language, memory, and motor). Three main findings were revealed by a random effects model analysis. First, a strong negative effect of dual tasks on walking performance (SMD = -0.68) confirmed that gait performance is adversely affected by dual tasks in people with PD. Second, the significant negative effect of dual tasks is present regardless of the mean level of single-task gait speed in a study. Third, dual-task walking speed deteriorates regardless of the type of dual task. Together, these results confirm that dual tasks severely affect walking performances in people with PD.

Relationship Between Dual-Task Gait Speed and Walking Activity Poststroke.

BACKGROUND AND PURPOSE: Gait speed does not adequately predict whether stroke survivors will be active in the community. This may be because traditional single-task gait speed does not sufficiently reproduce the demands of walking in the real world. This study assessed whether dual-task gait speed accounts for variance in daily ambulatory activity above what can be predicted with habitual (single task) gait speed in community-dwelling stroke survivors. METHODS: Twenty-eight community-dwelling individuals, 58.2 years of age (SD=16.6), 8.9 months poststroke (interquartile range, 3.7-19.4), completed a gait and cognitive task in single- and dual-task conditions. Daily ambulatory activity was captured using a physical activity monitor. A regression analysis examined R2 changes with single- and dual-task gait speed. RESULTS: Single-task gait speed explained 15.3% of the variance in daily ambulatory activity (P=0.04). Adding dual-task gait speed to the regression model increased the variance explained by an additional 20.6% (P=0.04). CONCLUSIONS: Gait speed assessed under attention-demanding conditions may improve explanation of variance in daily ambulatory activity after stroke.

Spoken sentence production in college students with dyslexia: working memory and vocabulary effects.

BACKGROUND: Individuals with dyslexia demonstrate syntactic difficulties on tasks of language comprehension, yet little is known about spoken language production in this population. AIMS: To investigate whether spoken sentence production in college students with dyslexia is less proficient than in typical readers, and to determine whether group differences can be attributable to cognitive differences between groups. METHODS & PROCEDURES: Fifty-one college students with and without dyslexia were asked to produce sentences from stimuli comprising a verb and two nouns. Verb types varied in argument structure and morphological form and nouns varied in animacy. Outcome measures were precision (measured by fluency, grammaticality and completeness) and efficiency (measured by response times). Vocabulary and working memory tests were also administered and used as predictors of sentence production performance. OUTCOMES & RESULTS: Relative to non-dyslexic peers, students with dyslexia responded significantly slower and produced sentences that were significantly less precise in terms of fluency, grammaticality and completeness. The primary predictors of precision and efficiency were working memory, which differed between groups, and vocabulary, which did not. CONCLUSIONS & IMPLICATIONS: College students with dyslexia were significantly less facile and flexible on this spoken sentence-production task than typical readers, which is consistent with previous studies of school-age children with dyslexia. Group differences in performance were traced primarily to limited working memory, and were somewhat mitigated by strong vocabulary.

Biomechanical Analysis of Dance for Parkinson's Disease: A Paradoxical Case Study of Balance and Gait Effects?

OBJECTIVES: This study aimed to measure the effects of a dance training program on subjective and objective balance and gait measures in a person with Parkinson's disease. DESIGN AND SETTING: The participant was measured via clinical scales and biomechanical balance and gait analyses pre- and post-16 weeks of dance participation at the University Center for Arts in Medicine. The dance program consisted of 75 minute sessions three days a week. RESULTS: Improved clinical scales included the Schwab and England scale (+10%), falls efficacy scale (-11 points), six-minute walk (+15.54m), and timed up and go (1.38s). Balance measures during three conditions (eyes open, eyes closed, and narrow stance) all demonstrated an increase (24-112%) in center of pressure path length, velocity (anteroposterior and mediolateral), sway area, and approximate entropy (anteroposterior and mediolateral). Spatiotemporal gait parameters improved during forward walking: velocity (+0.12m/s), cadence (+3.89steps/min), double support time (-2.02%), stride length (+0.07m), stride time (-0.03s), and backward walking: single support (+3.47%), double support (-7.0%), swing time (+3.4%), and stance time (-3.4%). CONCLUSIONS: Classic interpretation of the above measures may indicate a detriment in biomechanical balance effects concomitant with an improvement in gait. Alternative explanations explored suggest this paradox to be illusory.

Improved cognition while cycling in Parkinson's disease patients and healthy adults.

Persons with Parkinson's disease (PD) are typically more susceptible than healthy adults to impaired performance when two tasks (dual task interference) are performed simultaneously. This limitation has by many experts been attributed to limitations in cognitive resources. Nearly all studies of dual task performance in PD employ walking or balance-based motor tasks, which are commonly impaired in PD. These tasks can be performed using a combination of one or two executive function tasks. The current study examined whether persons with PD would demonstrate greater dual task effects (DTEs) on cognition compared to healthy older adults (HOAs) during a concurrent cycling task. Participants with and without PD completed a battery of 12 cognitive tasks assessing visual and verbal processing in the following cognitive domains: speed of processing, controlled processing, working memory and executive function. Persons with PD exhibited impairments compared to healthy participants in select tasks (i.e., 0-back, 2-back and operation span). Further, both groups unexpectedly exhibited dual task facilitation of response times in visual tasks across cognitive domains, and improved verbal recall during an executive function task. Only one measure, 2-back, showed a speed-accuracy trade-off in the dual task. These results demonstrate that, when paired with a motor task in which they are not impaired, people with PD exhibit similar DTEs on cognitive tasks as HOAs, even when these task effects are facilitative. More generally, these findings demonstrate that pairing cognitive tasks with cycling may actually improve cognitive performance which may have therapeutic relevance to cognitive decline associated with aging and PD pathology.

Aerobic Exercise Improves Mood, Cognition, and Language Function in Parkinson's Disease: Results of a Controlled Study.

OBJECTIVES: Parkinson's disease (PD) results in a range of non-motor deficits that can affect mood, cognition, and language, and many of these issues are unresponsive to pharmacological intervention. Aerobic exercise can improve mood and cognition in healthy older adults, although only a few studies have examined exercise effects on these domains in PD. The current study assesses the effects of aerobic exercise on aspects of cognition, mood, and language production in people with PD. METHODS: This study compares the effects of aerobic exercise to stretch-balance training and a no-contact control group in participants with idiopathic PD. The aerobic and stretch-balance groups trained three times a week for 16 weeks, while controls continued normal activities. Outcome measures included disease severity, mood, cognition (speed of processing, memory, and executive function), and language production (picture descriptions). Cognition and language were assessed in single and dual task conditions. RESULTS: Depressive symptoms increased only in the control group (p<.02). Executive function improved in the aerobic exercise group only in the single task (p=.007) and declined in controls in the dual task. Completeness of picture descriptions improved significantly more in the aerobic group than in the stretch-balance group (p<.02). CONCLUSIONS: Aerobic exercise is a viable intervention for PD that can be protective against increased depressive symptoms, and can improve several non-motor domains, including executive dysfunction and related aspects of language production. (JINS, 2016, 22, 878-889).

Executive Function and Ambiguous Sentence Comprehension.

PURPOSE: Sentence comprehension is a critical skill in today's literate society. Recent evidence suggests that processing and comprehending language taps cognitive as well as linguistic abilities, a finding that has critical import for clinicians who have clients with language disorders. To promote awareness of the impact of cognition, especially executive function (EF) and working memory (WM), this opinion article presents current views of how sentences are processed and links the various steps of the process to specific EF and WM subcomponents. METHOD: The article focuses on ambiguous sentences, pointing out the similar types of processing needed when resolving an ambiguity and performing EF tasks. RESULTS: We discuss the potential overlap between the neurobiology of sentence processing and EF and the evidence supporting a link between EF and sentence processes. CONCLUSION: Awareness of the potential role of EF and WM in sentence comprehension will help clinicians be more aware of potential cognitive-linguistic deficits in their clients. Future research will help to clarify the link between EF and sentence comprehension.

The relationship between balance confidence and control in individuals with Parkinson's disease.

INTRODUCTION: A broad range of subjective and objective assessments have been used to assess balance confidence and balance control in persons with Parkinson's disease (PD). However, little is known about the relationship between self-perceived balance confidence and actual balance control in PD. The purpose of this investigation was to determine the relationship between self-perceived balance confidence and objectively measured static/dynamic balance control abilities. METHODS: Forty-four individuals with PD participated in the study. Patients were stratified into 2 groups based on the modified Hoehn and Yahr (H&Y) disability score: early stage, H&Y ≤ 2.0 and moderate stage, H&Y ≥ 2.5. All participants completed the activities-specific balance confidence (ABC) scale and performed standing balance and gait initiation tasks to assess static and dynamic balance control. The center of pressure (COP) sway (CE95%Sway) during static balance and the peak distance between the projections of the COP and the center of mass (COM) in the transverse plane (COPCOM) during gait initiation were calculated. Pearson correlation analyses were conducted relating the ABC score and CE95%Sway and COPCOM. RESULTS: For early stage PD, there was a moderate correlation between ABC score and CE95%Sway (r = -0.56, R(2) = 0.32, p = 0.002), while no significant correlation was found between ABC score and COPCOM (r = -0.24, R(2) = 0.06, p = 0.227). For moderate stage PD, there was a moderate correlation between ABC score and COPCOM (r = 0.49, R(2) = 0.24, p = 0.044), while no correlation was found between ABC score and CE95%Sway (r = -0.19, R(2) = 0.04, p = 0.478). CONCLUSION: Individuals with different disease severities showed different relationships between balance confidence and actual static/dynamic balance control.

Unexpected dual task benefits on cycling in Parkinson disease and healthy adults: a neuro-behavioral model.

BACKGROUND: When performing two tasks at once, a dual task, performance on one or both tasks typically suffers. People with Parkinson's disease (PD) usually experience larger dual task decrements on motor tasks than healthy older adults (HOA). Our objective was to investigate the decrements in cycling caused by performing cognitive tasks with a range of difficulty in people with PD and HOAs. METHODS: Twenty-eight participants with Parkinson's disease and 20 healthy older adults completed a baseline cycling task with no secondary tasks and then completed dual task cycling while performing 12 tasks from six cognitive domains representing a wide range of difficulty. RESULTS: Cycling was faster during dual task conditions than at baseline, and was significantly faster for six tasks (all p<.02) across both groups. Cycling speed improved the most during the easiest cognitive tasks, and cognitive performance was largely unaffected. Cycling improvement was predicted by task difficulty (p<.001). People with Parkinson's disease cycled slower (p<.03) and showed reduced dual task benefits (p<.01) than healthy older adults. CONCLUSIONS: Unexpectedly, participants' motor performance improved during cognitive dual tasks, which cannot be explained in current models of dual task performance. To account for these findings, we propose a model integrating dual task and acute exercise approaches which posits that cognitive arousal during dual tasks increases resources to facilitate motor and cognitive performance, which is subsequently modulated by motor and cognitive task difficulty. This model can explain both the improvement observed on dual tasks in the current study and more typical dual task findings in other studies.

Investigating graph comprehension in students with dyslexia: an eye tracking study.

The purpose of this study was to examine graph comprehension in college students with developmental dyslexia. We investigated how graph types (line, vertical bar, and horizontal bar graphs), graphic patterns (single and double graphic patterns), and question types (point locating and comparison questions) differentially affect graph comprehension of students with and without dyslexia. Groups were compared for (1) reaction times for answering comprehension questions based on graphed data and (2) eye gaze times for specific graph subregions (x-axis, y-axis, pattern, legend, question, and answer). Dyslexic readers were significantly slower in their graph comprehension than their peers with group differences becoming more robust with the increasing complexity of graphs and tasks. In addition, dyslexic readers' initial eye gaze viewing times for linguistic subregions (question and answer) and total viewing times for both linguistic (question and answer) and nonlinguistic (pattern) subregions were significantly longer than their control peers' times. In spite of using elementary-level paragraphs for comprehension and simple graph forms, young adults with dyslexia needed more time to process linguistic and nonlinguistic stimuli. These findings are discussed relative to theories proposed to address fundamental processing deficits in individuals with dyslexia.

Associations between cognitive and gait performance during single- and dual-task walking in people with Parkinson disease.

BACKGROUND: Cognitive impairments in Parkinson disease (PD) manifest as deficits in speed of processing, working memory, and executive function and attention abilities. The gait impairment in PD is well documented to include reduced speed, shortened step lengths, and increased step-to-step variability. However, there is a paucity of research examining the relationship between overground walking and cognitive performance in people with PD. OBJECTIVE: This study sought to examine the relationship between both the mean and variability of gait spatiotemporal parameters and cognitive performance across a broad range of cognitive domains. DESIGN: A cross-sectional design was used. METHODS: Thirty-five participants with no dementia and diagnosed with idiopathic PD completed a battery of 12 cognitive tests that yielded 3 orthogonal factors: processing speed, working memory, and executive function and attention. Participants completed 10 trials of overground walking (single-task walking) and 5 trials of overground walking while counting backward by 3's (dual-task walking). RESULTS: All gait measures were impaired by the dual task. Cognitive processing speed correlated with stride length and walking speed. Executive function correlated with step width variability. There were no significant associations with working memory. Regression models relating speed of processing to gait spatiotemporal variables revealed that including dual-task costs in the model significantly improved the fit of the model. LIMITATIONS: Participants with PD were tested only in the on-medication state. CONCLUSIONS: Different characteristics of gait are related to distinct types of cognitive processing, which may be differentially affected by dual-task walking due to the pathology of PD.

Attentional resource allocation and swallowing safety in Parkinson's disease: a dual task study.

BACKGROUND: Aspiration pneumonia is a leading cause of death in persons with Parkinson's disease (PD). Despite this, the mechanisms underlying dysphagia in this population are unclear. To date, researchers have not investigated the effects of varying cognitive demand on objective measures of swallowing safety. This study assessed whether swallowing safety could be disrupted by increasing cognitive demands during the task of swallowing. METHODS: Twenty participants with moderate PD and dysphagia were tested while completing a novel dual task experimental paradigm under videofluoroscopy. In the dual task condition, participants swallowed 10 cc of thin liquid barium while completing a digits forward task. RESULTS: Four females and 16 males completed the study. Results revealed differential effects to swallowing safety based on baseline measures of cognitive flexibility and attention. Participants with mild impairment in cognitive flexibility and attention demonstrated cognitive-motor interference with worsening of both swallowing and cognitive performance. In contrast, participants who were most impaired in the domains of cognitive flexibility and attention improved swallowing safety in the dual task condition. Additionally, decreased swallow timing durations existed in the dual task condition compared to the single task condition. CONCLUSIONS: The results of this study support the hypothesis that supramedullary drive can influence the swallowing plan. Additionally, this study highlights the need for cognitive taxing during swallowing evaluations.