Impacts of Deep Brain Stimulation of the Globus Pallidus Internus on Swallowing: A Retrospective, Cross-Sectional Study.

Deep brain stimulation (DBS) is a common treatment for motor symptoms of Parkinson disease (PD), a condition associated with increased risk of dysphagia. The effect of DBS on swallowing function has not been comprehensively evaluated using gold-standard imaging techniques, particularly for globus pallidus internus (GPi) DBS. The objective of this retrospective, cross-sectional study was to identify differences in swallowing safety and timing kinematics among PD subjects with and without GPi DBS. We investigated the effects of unilateral and bilateral GPi DBS as well as the relationship between swallowing safety and DBS stimulation parameters, using retrospective analysis of videofluoroscopy recordings (71 recordings from 36 subjects) from electronic medical records. Outcomes were analyzed by surgical status (pre-surgical, unilateral DBS, bilateral DBS). The primary outcome was percent of thin-liquid bolus trials rated as unsafe, with Penetration-Aspiration Scale scores of 3 or higher. Secondary analyses included swallowing timing measures, relationships between swallowing safety and DBS stimulation parameters, and Dynamic Imaging Grade of Swallowing Toxicity ratings. Most subjects swallowed all boluses safely (19/29 in the pre-surgical, 16/26 in the unilateral DBS, and 10/16 in the bilateral DBS conditions). Swallowing safety impairment did not differ among stimulation groups. There was no main effect of stimulation condition on timing metrics, though main effects were found for sex and bolus type. Stimulation parameters were not correlated with swallowing safety. Swallowing efficiency and overall impairment did not differ among conditions. These results provide evidence that GPi DBS does not affect pharyngeal swallowing function. Further, prospective, investigations are needed.

Reflexive Airway Sensorimotor Responses in Individuals with Amyotrophic Lateral Sclerosis.

BACKGROUND: Progressive motor denervation in amyotrophic lateral sclerosis (ALS) leads to reduced expiratory cough flow and diminished airway clearance physiologic capacity. Although ALS is thought to primarily impact motor systems, preliminary data from our laboratory suggest degradation of afferent pathways that regulate reflexive cough responses to radiographically confirmed aspiration. We, therefore, aimed to delineate both sensory and motor responses to a tussigenic airway irritant in individuals with ALS compared to healthy controls. METHODS: Thirty-two individuals with ALS and 34 healthy age and gender-matched controls completed reflex cough testing. Capsaicin stimuli (0, 50, 100, 150, 200 µM) were presented in a randomized three-block design and motor (cough spirometry metrics) and sensory (patient-rated urge to cough, UtC) ratings collected. ALS patients underwent videofluoroscopy with penetration-aspiration ratings completed. Descriptives, Mann-Whitney U, and mixed models ANOVAs were performed. RESULTS: Sensory: Individuals with ALS demonstrated greater UtC sensitivity slopes (i.e., increased stimulus sensitivity) vs. healthy controls (p = 0.036). Within the ALS group, however, silent aspirators (PAS = 8) demonstrated blunted UtC sensitivity slopes compared to ALS patients who did not (PAS ≤ 7, p = 0.0001). Motor: Compared to healthy controls, ALS individuals demonstrated reduced peak expiratory flow rates (p = 0.004), longer peak expiratory rise time (p = 0.017), and lower cough volume acceleration (p = 0.000). CONCLUSIONS: ALS individuals demonstrated increased sensitivity to an upper airway irritant; however, they demonstrated slower and weaker expiratory cough motor output compared to healthy controls. In ALS silent aspirators, blunted sensorimotor responses were observed, suggesting that sensory degradation may occur at the final or most severe stage of bulbar disease progression.

Management of Dysphagia in Acquired and Progressive Neurologic Conditions.

As the act of deglutition involves much of the central and peripheral nervous systems, neurologic disease can affect swallowing behaviors ranging from mild to profound in severity. The key in working with neurogenic dysphagia is to have a solid foundation in normal swallowing processes, including neural control. Within this framework, then, understanding how the neurologic condition affects neural control will guide hypothesis-based assessment and evidence-based treatment. The purpose of this article is to provide an overview of evaluation and treatment of neurogenic dysphagia in adult populations as well to propose assessment of co-occurring speech, language, and airway compromise. Furthermore, it is vital to be familiar with ethical decision making and end-of-life issues. Continuing education in the form of research articles, conferences, and professional discussion boards is useful in maintaining a high level of service delivery. Whenever possible, an inter- or transdisciplinary approach is recommended.

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.

The Vocal Flutter of Multiple System Atrophy: A Parkinsonian-Type Phenomenon?

BACKGROUND: Early features of multiple system atrophy (MSA) are similar to those in Parkinson's disease (PD), which can challenge differential diagnosis. Identifying clinical markers that help distinguish MSA from forms of parkinsonism is essential to promptly implement the most appropriate management plan. In the context of a thorough neurological evaluation, the presence of a vocal flutter might be considered a potential feature of MSA-parkinsonian type (MSA-P). CASES: This case series describes clinical histories of 3 individuals with MSA-P. In each case, vocal flutter was detected during neurological and motor speech evaluations. It seemed to be a concomitant feature with the constellation of other signs and symptoms that led to the clinical diagnosis. LITERATURE REVIEW: The vocal flutter may be described as pitch and loudness fluctuations during phonation. Different from a vocal tremor, the flutter phenomenon has higher oscillation frequencies. The neuropathological underpinnings of vocal flutter may be related to generalized laryngeal dysfunction that is commonly described in MSA-P. CONCLUSION: Vocal flutter may be a unique speech feature in some individuals who have MSA-P. Future studies using perceptual and acoustic measures of speech are warranted to quantify these observations and directly compare to other MSA variants, PD, and a control group.

Impact of Vocal Fry and Speaker Gender on Listener Perceptions of Speaker Personal Attributes.

OBJECTIVES: Many studies have investigated listener perceptions of speakers who use vocal fry, but results remain mixed. This study aimed to investigate how vocal fry and speaker gender impact listener perceptions of a speaker's likeability, intelligence, attractiveness, and salary-attainment, described as "attributes." We hypothesized speakers with vocal fry would be evaluated more negatively on all attributes than speakers without vocal fry, with female speakers rated more negatively than male speakers. METHODS: Twenty nine listeners rated male and female speakers with and without vocal fry on these attributes using a five-point Likert scale. STUDY DESIGN: This experiment used a randomized mixed methods design with Vocal Fry and Speaker Gender as independent variables predicting attribute ratings. RESULTS: Results of a MANOVA revealed a significant main effect for Fry (Λ = 0.607; F(4,29) = 4.691; ηp2 = 0.393; P = 0.005), where speakers with vocal fry were rated significantly more negatively than speakers without vocal fry. Additionally, there was a significant Fry by Speaker Gender interaction where female speakers without vocal fry were rated as significantly more attractive [F(1,36) = 13.964; P= 0.003; ηp2 = 0.304] and intelligent [F(1,36) = 10.740; P = 0.001; ηp2 = 0.251] than female speakers with vocal fry. There was no significant difference between ratings of male speakers in either fry condition. CONCLUSIONS: Female speakers with vocal fry were rated as less attractive and intelligent than female speakers without vocal fry, but perception of male speakers did not change whether or not vocal fry was present in the acoustic signal.

Peak morphology and scalp topography of the pharyngeal sensory-evoked potential.

The initiation of the pharyngeal stage of swallowing is dependent upon sensory input to the brainstem and cortex. The event-related evoked potential provides a measure of neuronal electrical activity as it relates to a specific stimulus. Air-puff stimulation to the posterior pharyngeal wall produces a sensory-evoked potential (PSEP) waveform. The goal of this study was to characterize the scalp topography and morphology for the component peaks of the PSEP waveform. Twenty-five healthy men and women served as research participants. PSEPs were measured via a 32-electrode cap (10-20 system) connected to SynAmps2 Neuroscan EEG System. Air puffs were delivered directly to the oropharynx using a thin polyethylene tube connected to a flexible laryngoscope. The PSEP waveform is characterized by four early- and mid-latency component peaks: an early positivity (P1) and negativity (N1), followed by a mid-latency positivity (P2) and negativity (N2). The early positive peak P1 is localized bilaterally to the lateral parietal scalp, the N1 medially in the frontoparietal region, and the P2 and N2 with diffuse scalp locations. Somatosensory and premotor regions are possible anatomical correlates of peak locations. Based on the latencies of the peaks, they are likely analogous to somatosensory- and respiratory-related evoked potential peaks.

Impact of Tussigenic Stimuli on Perceived Upper Airway Sensation and Motor Cough Response Following Total Laryngectomy.

BACKGROUND: Total laryngectomy (TL) is standard intervention for carcinoma of the head and neck or, in cases of non-functional larynx, as a result of disease or radiation exposure. Laryngeal extirpation serves as a unique human model of both recurrent and superior laryngeal nerve section and offers insight into motor and sensory aspects of cough: both volitional and in response to tussigenic stimuli. While motor changes in cough function are expected among those status post-TL due to postoperative reconstruction of the upper airway, motor cough parameters have not been well described and sensory aspects of cough are unknown in this population, which provides insight into a vagal denervation model in humans. METHODS: Data were collected from three groups totaling 80 adults (39 male), including 25 healthy younger adults (HYA), 27 healthy older adults (HOA), and 28 adults post-TL. Cough was elicited both upon command and in response to nebulized capsaicin. Outcome measures included urge to cough and cough airflows. RESULTS: Kruskal-Wallis test showed that two of the three groups differed significantly by urge to cough χ2(2, N = 244) = 8.974, p = 0.011. Post hoc analysis showed that post-TL subjects had reduced perceived urge to cough at all concentrations of capsaicin (p < 0.05). Cough airflows were significantly reduced for post-TL subjects compared to healthy controls in all metrics except post-peak phase integral (PPPI) for which HOA and TLs were comparable under both volitional and capsaicin-induced conditions. CONCLUSIONS: These findings support the hypothesis that both cough airflow and sensations are significantly reduced in post-TL subjects when compared with HOA. Interestingly, HOA and post-TL subjects have comparably reduced UTC and cough airflows when compared to HYA. The only metric of cough airflow for which these groups differ is the PPPI, which may be a compensatory adaptation for reduced cough airflows and/or sensation.

Lung volume during swallowing: single bolus swallows in healthy young adults.

PURPOSE: This study examined the relationship between swallowing and lung volume initiation in healthy adults during single swallows of boluses differing in volume and consistency. Differences in lung volume according to respiratory phase surrounding the swallow were also assessed. METHOD: Nine men and 11 women between the ages of 19 and 28 years served as study participants. Lung volume and respiratory phase data were recorded as each participant completed 5 trials each of 10-mL and 20-mL water boluses by cup, and thin and thick paste boluses by spoon, presented in randomized order. RESULTS: Significant differences in lung volume at swallow initiation were found based on bolus consistency but not on bolus volume. No differences were found for lung volume initiation based on the respiratory phase surrounding the swallow or for the respiratory pattern based on bolus volume or consistency. CONCLUSION: Findings of this study extend the existing knowledge base regarding the interaction of the swallow and respiratory systems by identifying targeted lung volumes at swallow initiation. In addition to other swallow-related biomechanical events and respiratory phase relationships surrounding a swallow, the lung volume at swallow initiation may be an important consideration when investigating swallow physiology and physiopathy.

Submental sEMG and hyoid movement during Mendelsohn maneuver, effortful swallow, and expiratory muscle strength training.

PURPOSE: This study investigated the concurrent biomechanical and electromyographic properties of 2 swallow-specific tasks (effortful swallow and Mendelsohn maneuver) and 1 swallow-nonspecific (expiratory muscle strength training [EMST]) swallow therapy task in order to examine the differential effects of each on hyoid motion and associated submental activation in healthy adults, with the overall goal of characterizing task-specific and overload properties of each task. METHOD: Twenty-five healthy male and female adults (M = 25 years of age) participated in this prospective, experimental study with 1 participant group. Each participant completed all study tasks (including normal swallow, Mendelsohn maneuver swallow, effortful swallow, and EMST task) in random order during concurrent videofluoroscopy and surface electromyography recording. RESULTS: Results revealed significant differences in the trajectory of hyoid motion as measured by overall displacement and angle of elevation of the hyoid bone. As well, timing of hyoid movement and amplitude differences existed between tasks with regard to the activation of the submental musculature. CONCLUSIONS: Study results demonstrated differential effects of the 3 experimental tasks on the principles of task specificity and overload. These principles are important in the development of effective rehabilitative programs. Subsequent direction for future research is suggested.

Cough physiology in elderly women with nontuberculous mycobacterial lung infections.

Elderly white, thin, nonsmoking women appear to be more susceptible to lung infections with Mycobacterium avium complex and other nontuberculous mycobacteria (NTM). It has been postulated that such disease in women is related to suppression of their cough. We hypothesized that patients with pulmonary NTM (pNTM) infections may have altered cough physiology compared with unaffected control subjects. We used capsaicin-induced cough to assess the cough reflex in pNTM subjects. Eight elderly white women with stable chronic pNTM infections and six unaffected age-matched control subjects were recruited. There was no significant difference between groups in capsaicin-elicited cough motor response, airflow pattern, or cough frequency. The urge-to-cough (UTC) score at the lowest capsaicin concentration was significantly lower in pNTM than control subjects (P < 0.05). There were no significant differences in the UTC score between pNTM and control subjects at >50 µM capsaicin. These results suggest lower UTC sensitivity to the lowest concentration of capsaicin in pNTM than control subjects. In other words, the pNTM subjects do not sense a UTC when the stimulus is relatively small.NEW & NOTEWORTHY This study investigates the cough motor response and cough sensitivity in patients with nontuberculous mycobacteria (NTM) infection. In elderly white female pulmonary NTM subjects, we demonstrated a capacity to produce coughs similar to that of age-matched control subjects but decreased cough sensitivity in response to a low dose of capsaicin compared with control subjects. These findings are important to understand the pathophysiological mechanisms resulting in NTM disease in elderly white women and/or the syndrome developing in elderly white female NTM patients.

Negative emotional stimulation decreases respiratory sensory gating in healthy humans.

We tested the hypothesis that negative emotions decrease the respiratory-related evoked potentials (RREP) sensory gating (RSG). RREP were elicited by paired inspiratory occlusions. RSG was calculated as the difference in the averaged RREP peak N1 amplitude between the second (S2) and the first occlusion (S1). RSG was compared between unpleasant and neutral emotional conditions elicited by viewing affective pictures from the IAPS system in thirteen healthy adults. Results are expressed as median [min; max]. Compared to neutral pictures, viewing unpleasant pictures decreased the RREP N1(S1) amplitude (-3.37 µV [-4.62; -1.37] versus -4.59 µV [-6.08; -1.36]; p=0.017) but not the RREP N1(S2) amplitude (-0.26 [-3.24; 2.36] versus -0.7 [-1.54; 3.6]; p = 0.68), and reduced the difference score S2-S1 (3.73 µV [0; 5.82] versus 4.79 µV [3; 6.2]; p = 0.038). We concluded that a negative emotional stimulation could attract subject's attention to the detriment of the respiratory sensory inputs and produced an overall decrease in the RSG. This latter finding might participate in an over-perception of repeatedly presented respiratory stimuli.

Comparison of voluntary and reflex cough effectiveness in Parkinson's disease.

INTRODUCTION: Multiple airway protective mechanisms are impacted with Parkinson's disease (PD), including swallowing and cough. Cough serves to eject material from the lower airways, and can be produced voluntarily (on command) and reflexively in response to aspirate material or other airway irritants. Voluntary cough effectiveness is reduced in PD however it is not known whether reflex cough is affected as well. The goal of this study was to compare the effectiveness between voluntary and reflex cough in patients with idiopathic PD. METHODS: Twenty patients with idiopathic PD participated. Cough airflow data were recorded via facemask in line with a pneumotachograph. A side delivery port connected the nebulizer for delivery of capsaicin, which was used to induce cough. Three voluntary coughs and three reflex coughs were analyzed from each participant. A two-way repeated measures analysis of variance was used to compare voluntary versus reflex cough airflow parameters. RESULTS: Significant differences were found for peak expiratory flow rate (PEFR) and cough expired volume (CEV) between voluntary and reflex cough. Specifically, both PEFR and CEV were reduced for reflex as compared to voluntary cough. CONCLUSION: Cough PEFR and CEV are indicative of cough effectiveness in terms of the ability to remove material from the lower airways. Differences between these two cough types likely reflect differences in the coordination of the respiratory and laryngeal subsystems. Clinicians should be aware that evaluation of cough function using voluntary cough tasks overestimates the PEFR and CEV that would be achieved during reflex cough in patients with PD.

Lung volume measured during sequential swallowing in healthy young adults.

PURPOSE: Outcomes from studying the coordinative relationship between respiratory and swallow subsystems are inconsistent for sequential swallows, and the lung volume at the initiation of sequential swallowing remains undefined. The first goal of this study was to quantify the lung volume at initiation of sequential swallowing ingestion cycles and to identify the respiratory pattern(s) surrounding each sequential swallow ingestion cycle. The second goal was to compare these results with existing data for single swallows. METHOD: Twenty healthy young adults served as participants, 9 males and 11 females, between 19 and 28 years of age (M = 22 years of age). Participants completed 2 trials each of 100 mL of water self-delivered by cup and by straw. Calibrated respiratory inductance plethysmography, surface electromyography, and a contact throat microphone were used to detect respiratory parameters, identify swallow-related muscle contraction, and identify swallowing sounds, respectively. RESULTS: Significantly higher lung volume initiation for trials delivered by straw and more variable respiratory patterns surrounding cup and straw sequential swallowing ingestion cycles existed compared with single swallows. CONCLUSIONS: Results show that as the physiologic demands of swallowing deviate from single, small bolus swallows, the integration of the swallowing and respiratory systems change. This may reflect obligate differences in airway protection strategy and prolonged competition for respiratory resources.

Cortical gating of oropharyngeal sensory stimuli.

Somatosensory evoked potentials provide a measure of cortical neuronal activation in response to various types of sensory stimuli. In order to prevent flooding of the cortex with redundant information various sensory stimuli are gated cortically such that response to stimulus 2 (S2) is significantly reduced in amplitude compared to stimulus 1 (S1). Upper airway protective mechanisms, such as swallowing and cough, are dependent on sensory input for triggering and modifying their motor output. Thus, it was hypothesized that central neural gating would be absent for paired-air puff stimuli applied to the oropharynx. Twenty-three healthy adults (18-35 years) served as research participants. Pharyngeal sensory evoked potentials (PSEPs) were measured via 32-electrode cap (10-20 system) connected to SynAmps(2) Neuroscan EEG System. Paired-pulse air puffs were delivered with an inter-stimulus interval of 500 ms to the oropharynx using a thin polyethylene tube connected to a flexible laryngoscope. Data were analyzed using descriptive statistics and a repeated measures analysis of variance. There were no significant differences found for the amplitudes S1 and S2 for any of the four component PSEP peaks. Mean gating ratios were above 0.90 for each peak. Results supports our hypothesis that sensory central neural gating would be absent for component PSEP peaks with paired-pulse stimuli delivered to the oropharynx. This may be related to the need for constant sensory monitoring necessary for adequate airway protection associated with swallowing and coughing.

Evidence-based systematic review: Oropharyngeal dysphagia behavioral treatments. Part I--background and methodology.

Evidence-based systematic reviews (EBSRs), in conjunction with clinical expertise and client values, are invaluable tools for speech-language pathologists and audiologists. This article provides an overview of the levels-of-evidence scheme used by the American Speech-Language-Hearing Association (ASHA) to conduct systematic reviews. The goal of ASHA reviews is to provide a tool to help clinicians determine the best treatment course for their clients. We present a collaborative project between ASHA's National Center for Evidence-based Practice in Communication Disorders and the Department of Veterans Affairs (VA) that examined seven behavioral swallowing treatments for disordered and nondisordered populations. The methodology used in a series of reviews conducted by ASHA and the VA will be discussed, including the development of clinical questions, search parameters, inclusion/exclusion criteria, and literature search results. Findings from the series of reviews as well as the practical applications of EBSRs will be reported in subsequent articles in this series.

Evidence-based systematic review: Oropharyngeal dysphagia behavioral treatments. Part II--impact of dysphagia treatment on normal swallow function.

This article is the second in a series of evidence-based systematic reviews. Data reported cover the impact of dysphagia behavioral interventions on swallow physiology in healthy adults. The behavioral treatments investigated were three postural interventions--side lying, chin tuck, and head rotation--and four swallowing maneuvers--effortful swallow, the Mendelsohn maneuver, supraglottic swallow, and super-supraglottic swallow. A systematic search of the dysphagia literature was conducted in 14 electronic databases. Seventeen studies meeting the inclusion criteria were evaluated for methodological quality with the American Speech-Language-Hearing Association's levels-of-evidence scheme and were characterized by research stage (i.e., exploratory, efficacy, effectiveness, cost-benefit/public policy research). Effect sizes were calculated when possible. All studies were exploratory research ranging from two to five of seven possible quality markers. The majority of studies (8 of 17) investigated effortful swallow. Three studies examined the Mendelsohn maneuver, chin tuck, supraglottic swallow, and super-supraglottic swallow and two studies addressed head rotation. No study addressed side lying. For non disordered populations, the existing evidence demonstrates differential effects of postural changes and maneuvers on swallowing physiology. Some effects reinforced existing recommendations for the applications of the interventions, while others suggested new ways that the treatments may impact swallow function. Avenues for future research are suggested.

Evidence-based systematic review: Oropharyngeal dysphagia behavioral treatments. Part III--impact of dysphagia treatments on populations with neurological disorders.

This evidence-based systematic review (EBSR) is part of a series of reviews examining the state of the research regarding behavioral interventions for dysphagia. This EBSR focuses primarily on dysphagia secondary to neurological disorders (e.g., brain injury, stroke, Parkinson's disease, and dementia). The seven behavioral treatments investigated were three postural interventions (side lying, chin tuck, and head rotation) and four swallowing maneuvers (effortful swallow, Mendelsohn, supraglottic swallow, and super-supraglottic swallow). We systematically searched the dysphagia literature from March 2007 to April 2008 using 14 electronic databases. Seven studies met the inclusion and exclusion criteria and were evaluated for methodological quality and stage of research. Of the included studies, only two were judged to be efficacy research; the remaining five were considered exploratory. Methodological quality of studies ranged from one to seven out of eight possible quality markers. Five of seven treatment interventions were addressed by at least one study. No studies were found to address the effortful swallow or the super-supraglottic swallow. Currently, limited evidence from seven studies shows the potential effects of dysphagia behavioral interventions for select groups of individuals with neurologically induced dysphagia. Further research is needed to evaluate the effectiveness of these and the remaining interventions with various populations with neurological disorders.

Evidence-based systematic review: Oropharyngeal dysphagia behavioral treatments. Part IV--impact of dysphagia treatment on individuals' postcancer treatments.

This evidence-based systematic review (EBSR) is part of a series of reviews investigating swallowing behavioral treatments for individuals with dysphagia. This EBSR focuses primarily on individuals with dysphagia postcancer treatments. The seven behavioral interventions under review included three postural interventions (side lying, chin tuck, and head rotation) and four swallowing maneuvers (effortful swallow, Mendelsohn, supraglottic swallow, and super-supraglottic swallow). We systematically searched the dysphagia literature from March 2007 to April 2008. Six studies that met the inclusion and exclusion criteria were evaluated for methodological quality and characterized by research stage. Effect sizes were calculated when possible. All studies included were considered exploratory, with quality-marker scores ranging from 1 to 4 out of 7 possible markers. Five studies examined one or more of the four swallowing maneuvers, and one study addressed the chin-tuck posture. No studies addressed side lying or head rotation. Currently, limited evidence exists from six studies showing the positive effects of behavioral swallowing interventions for populations with structural disorder. Because of the range of structural deficits resulting from cancers and their treatments, further research is needed that evaluates specific intervention effectiveness.