A Core Outcome Set for Research Evaluating Interventions to Enable Communication in Patients With an Artificial Airway: An International Delphi Consensus Study (Comm-COS).

OBJECTIVES: Critically ill adults requiring artificial airways experience profound communication deficits. Studies of interventions supporting communication report disparate outcomes, creating subsequent challenges in the interpretation of their effectiveness. Therefore, we aimed to develop international consensus for a communication core outcome set (Comm-COS) for future trials of communication interventions in this population. DESIGN: 1) Systematic review, 2) patient/family interviews, 3) two-round modified Delphi, and 4) virtual consensus meetings with a final voting round. A multidisciplinary expert steering committee oversaw all stages. SETTING: Interviews and consensus meetings were conducted via videoconferencing. Digital methods were used for Delphi and final Comm-COS voting. SUBJECTS: Three stakeholder groups: 1) patient and family members with lived experience within 3 years, 2) clinicians with experience working in critical care, and 3) researchers publishing in the field. INTERVENTION: None. MEASUREMENTS AND MAIN RESULTS: We identified 59 outcomes via our systematic review, 3 unique outcomes from qualitative interviews, and 2 outcomes from our steering committee. Following item reduction, 32 outcomes were presented in Delphi round 1; 134 participants voted; 15 patient/family (11%), 91 clinicians (68%), and 28 researchers (21%). Nine additional outcomes were generated and added to round 2; 106 (81%) participants voted. Following completion of the consensus processes, the Comm-COS includes seven outcomes: 1) changes in emotions and wellbeing associated with ability to communicate, 2) physical impact of communication aid use, 3) time to functional communication, 4) ability to communicate healthcare needs (comfort/care/safety/decisions), 5) conversation agency, 6) ability to establish a communication connection to develop and maintain relationships, and 7) acceptability of the communication intervention. CONCLUSIONS: This is the first COS to specifically focus on communication for critically ill adults. Limitations for operationalization include selection of measures to use with these outcomes. Identification of suitable measures and adoption of the Comm-COS in future trials will help establish effective interventions to ameliorate the highly prevalent and negative experience of communicative incapacity.

Tracheostomy-related durable medical equipment: Insurance coverage, gaps, and barriers.

PURPOSE: Tracheostomy care is supply- and resource-intensive, and airway-related adverse events in community settings have high rates of readmission and mortality. Devices are often implicated in harm, but little is known about insurance coverage, gaps, and barriers to obtaining tracheostomy-related medically necessary durable medical equipment. We aimed to identify barriers patients may encounter in procuring tracheostomy-related durable medical equipment through insurance plan coverage. MATERIALS AND METHODS: Tracheostomy-related durable medical equipment provisions were evaluated across insurers, extracting data via structured telephone interviews and web-based searches. Each insurance company was contacted four times and queried iteratively regarding the range of coverage and co-pay policies. Outcome measures include call duration, consistency of explanation of benefits, and the number of transfers and disconnects. We also identified six qualitative themes from patient interviews. RESULTS: Tracheostomy-related durable medical equipment coverage was offered in some form by 98.1 % (53/54) of plans across 11 insurers studied. Co-pays or deductibles were required in 42.6 % (23/54). There was significant variability in out-of-pocket expenditures. Fixed co-pays ranged from $0-30, and floating co-pays ranged from 0 to 40 %. During phone interviews, mean call duration was 19 ± 10 min, with an average of 2 ± 1 transfers between agents. Repeated calls revealed high information variability (mean score 2.4 ± 1.5). Insurance sites proved challenging to navigate, scoring poorly on usability, literacy, and information quality. CONCLUSIONS: Several factors may limit access to potentially life-saving durable medical equipment for patients with tracheostomy. Barriers include out-of-pocket expenditures, lack of transparency on coverage, and low-quality information. Further research is necessary to evaluate patient outcomes.

Instrument adaptation and preliminary validation study of the Laryngeal Hypersensitivity Questionnaire used for assessment of laryngeal symptoms in patients with artificial airways.

BACKGROUND: The Newcastle Laryngeal Hypersensitivity Questionnaire (LHQ) was developed to measure abnormal laryngeal sensation and was originally validated in a patient sample from otolaryngologic and respiratory outpatient clinics. Modification is needed for patients who are mechanically ventilated via an endotracheal tube or a tracheostomy tube. OBJECTIVES: We sought to adapt and preliminarily validate a modified version of the LHQ appropriate for nurses and other clinicians to administer in acute hospital settings called the LHQ-Acute (LHQ-A). METHODS: Internal consistency and construct validity analyses using secondary data from patients at a tertiary teaching hospital who presented with symptoms of laryngeal irritability/hypersensitivity between September 2012 and October 2013 were performed. RESULTS: A total of 131 patients, most complaining of coughing and dysphonia, with a median age of 58 (interquartile range: 48, 66) years and 29 healthy participants with a median age of 62 (interquartile range: 50, 66) years were analysed. The original LHQ was reduced from 14 questions with responses on a 7-point scale to the LHQ-A containing 13 questions with responses on a 4-point scale. Correlations between items of the LHQ and LHQ-A were similar, and internal consistency was excellent and highly comparable, with Cronbach's alpha = 0.906 and 0.902, respectively. CONCLUSIONS: The LHQ-A, which has been adapted for nurses and other clinicians to administer to a critically ill patient population, demonstrated comparable reliability and validity to the original LHQ. Validation of the LHQ-A in independent patient populations from acute settings is necessary to better understand norms and changes during recovery from acute illness.

Post-extubation Assessment of Laryngeal Symptoms and Severity (PALSS) in the Intensive Care Unit: Protocol of a Prospective Cohort Study.

Aims: The Post-extubation Assessment of Laryngeal Symptoms and Severity (PALSS) study systematically evaluates patient symptoms related to endotracheal intubation with mechanical ventilation, assesses laryngeal injury and voice function after extubation, and develops a screening tool to identify patients with clinically important, post-extubation laryngeal injury. Design: Single-center, prospective observational cohort study conducted in 6 intensive care units (ICU). Methods: Patients ≥18 years old who are orally intubated and mechanically ventilated in an ICU and meet eligibility criteria will undergo flexible laryngoscopy, with a sample size goal of 300 completed laryngoscopies. Primary outcome measures include signs and symptoms of laryngeal injury, including voice symptoms and alterations in swallowing, measured using the Laryngeal Hypersensitivity Questionnaire-Acute and Voice Symptom Scale questionnaires respectively. Data will be collected within 72 hours post-extubation and at 7-day follow-up or hospital discharge (whichever occurs first). Data will be analyzed using descriptive statistics, regression models, and predictive modeling using machine learning. Discussion: The findings of this study will describe the clinical signs and symptoms of laryngeal injury post-extubation. Conclusion: The PALSS study will provide insights for future studies that explore laryngeal injuries using flexible laryngoscopy after endotracheal intubation. Implications for patient care: Identifying signs and symptoms of laryngeal injury after endotracheal intubation will facilitate the development of a screening tool that will assist in early identification of post-extubation laryngeal injury, and aid in decreasing short- and long-term complications of endotracheal intubation. Reporting Method: SPIRIT. Patient or Public Contribution: Patients were study participants; and family members provided informed consent when the patient lacked decision-making capacity.

Does Medialization Improve Swallowing Function in Patients with Unilateral Vocal Fold Paralysis? A Systematic Review.

Glottal incompetence caused by unilateral vocal fold paralysis (UVFP) is a common cause of dysphagia and aspiration. Treatments targeted at reducing glottal incompetence by injection augmentation or medialization thyroplasty are well established at improving voice outcomes, but improvements in swallowing function are less clear. The objective of this systematic review was to determine the impact of vocal fold medialization on dysphagia outcomes. Six electronic bibliographic databases and one clinical trial registry were searched on 3/13/2020. Our patient population were adult patients with verified UVFP that underwent vocal fold medialization. We limited review to prospective studies that had formal dysphagia assessment both before and after medialization. Nine studies met selection criteria (7 prospective case series and 2 prospective cohort studies) totaling 157 patients. The most common etiology of UVFP was iatrogenic (74/157; 47%). The majority of patients underwent injection augmentation (92/157; 59%), and the remaining underwent medialization thyroplasty. A variety of methods were used to assess changes in dysphagia including patient-reported outcome measures, flexible endoscopic evaluation of swallowing, videofluoroscopic swallow study, and high-resolution manometry. 7/9 studies demonstrated clinically significant improvement in swallowing function following medialization; 4/9 studies demonstrated statistically significant improvement, and three studies did not show statistically significant improvement after intervention. Study participants and outcome measures evaluating swallowing function in this review were heterogeneous. Moreover, the reviewed studies are concerning for multiple risks of bias impacting their conclusions. Taken together, this systematic review demonstrates limited evidence that injection augmentation and medialization thyroplasty improve swallowing function and/or safety.

Dysphagia in Intensive Care Evaluation (DICE): An International Cross-Sectional Survey.

Dysphagia occurs commonly in the intensive care unit (ICU). Despite the clinical relevance, there is little worldwide research on prevention, assessment, evaluation, and/or treatment of dysphagia for ICU patients. We aimed to gain insight into this international knowledge gap. We conducted a multi-center, international online cross-sectional survey of adult ICUs. Local survey distribution champions were recruited through professional and personal networks. The survey was administered from November 2017 to June 2019 with three emails and a final telephone reminder. Responses were received from 746 ICUs (26 countries). In patients intubated > 48 h, 17% expected a > 50% chance that dysphagia would develop. This proportion increased to 43% in patients intubated > 7 days, and to 52% in tracheotomized patients. Speech-language pathologist (SLP) consultation was available in 66% of ICUs, only 4% reported a dedicated SLP. Although 66% considered a routine post-extubation dysphagia protocol important, most (67%) did not have a protocol. Few ICUs routinely assessed for dysphagia after 48 h of intubation (30%) or tracheostomy (41%). A large proportion (46%) used water swallow screening tests to determine aspiration, few (8%) used instrumental assessments (i.e., flexible endoscopic evaluation of swallowing). Swallowing exercises were used for dysphagia management by 30% of ICUs. There seems to be limited awareness among ICU practitioners that patients are at risk of dysphagia, particularly as ventilation persists, protocols, routine assessment, and instrumental assessments are generally not used. We recommend the development of a research agenda to increase the quality of evidence and ameliorate the implementation of evidence-based dysphagia protocols by dedicated SLPs.

An International Commentary on Dysphagia and Dysphonia During the COVID-19 Pandemic.

COVID-19 has had an impact globally with millions infected, high mortality, significant economic ramifications, travel restrictions, national lockdowns, overloaded healthcare systems, effects on healthcare workers' health and well-being, and large amounts of funding diverted into rapid vaccine development and implementation. Patients with COVID-19, especially those who become severely ill, have frequently developed dysphagia and dysphonia. Health professionals working in the field have needed to learn about this new disease while managing these patients with enhanced personal protective equipment. Emerging research suggests differences in the clinical symptoms and journey to recovery for patients with COVID-19 in comparison to other intensive care populations. New insights from outpatient clinics also suggest distinct presentations of dysphagia and dysphonia in people after COVID-19 who were not hospitalized or severely ill. This international expert panel provides commentary on the impact of the pandemic on speech pathologists and our current understanding of dysphagia and dysphonia in patients with COVID-19, from acute illness to long-term recovery. This narrative review provides a unique, comprehensive critical appraisal of published peer-reviewed primary data as well as emerging previously unpublished, original primary data from across the globe, including clinical symptoms, trajectory, and prognosis. We conclude with our international expert opinion on what we have learnt and where we need to go next as this pandemic continues across the globe.

Laryngeal Injury and Upper Airway Symptoms After Endotracheal Intubation During Surgery: A Systematic Review and Meta-analysis.

Laryngeal injury from intubation can substantially impact airway, voice, and swallowing, thus necessitating multidisciplinary interventions. The goals of this systematic review were (1) to review the types of laryngeal injuries and their patient-reported symptoms and clinical signs resulting from endotracheal intubation in patients intubated for surgeries and (2) to better understand the overall the frequency at which these injuries occur. We conducted a search of 4 online bibliographic databases (ie, PubMed, Embase, Cumulative Index of Nursing and Allied Health Literature [CINAHL], and The Cochrane Library) and ProQuest and Open Access Thesis Dissertations (OPTD) from database inception to September 2019 without restrictions for language. Studies that completed postextubation laryngeal examinations with visualization in adult patients who were endotracheally intubated for surgeries were included. We excluded (1) retrospective studies, (2) case studies, (3) preexisting laryngeal injury/disease, (4) patients with histories of or surgical interventions that risk injury to the recurrent laryngeal nerve, (5) conference abstracts, and (6) patient populations with nonfocal, neurological impairments that may impact voice and swallowing function, thus making it difficult to identify isolated postextubation laryngeal injury. Independent, double-data extraction, and risk of bias assessment followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and the Cochrane Collaboration's criteria. Twenty-one articles (1 cross-sectional, 3 cohort, 5 case series, 12 randomized controlled trials) representing 21 surgical studies containing 6140 patients met eligibility criteria. The mean patient age across studies reporting age was 49 (95% confidence interval [CI], 45-53) years with a mean intubation duration of 132 (95% CI, 106-159) minutes. Studies reported no injuries in 80% (95% CI, 69-88) of patients. All 21 studies presented on type of injury. Edema was the most frequently reported mild injury, with a prevalence of 9%-84%. Vocal fold hematomas were the most frequently reported moderate injury, with a prevalence of 4% (95% CI, 2-10). Severe injuries that include subluxation of the arytenoids and vocal fold paralysis are rare (<1%) outcomes. The most prevalent patient complaints postextubation were dysphagia (43%), pain (38%), coughing (32%), a sore throat (27%), and hoarseness (27%). Overall, laryngeal injury from short-duration surgical intubation is common and is most often mild. No uniform guidelines for laryngeal assessment postextubation from surgery are available and hoarseness is neither a good indicator of laryngeal injury or dysphagia. Protocolized screening for dysphonia and dysphagia postextubation may lead to improved identification of injury and, therefore, improved patient outcomes and reduced health care utilization.

A Consensus Statement for the Management and Rehabilitation of Communication and Swallowing Function in the ICU: A Global Response to COVID-19.

OBJECTIVE: To identify core practices for workforce management of communication and swallowing functions in coronavirus disease 2019 (COVID-19) positive patients within the intensive care unit (ICU). DESIGN: A modified Delphi methodology was used, with 3 electronic voting rounds. AGREE II and an adapted COVID-19 survey framework from physiotherapy were used to develop survey statements. Sixty-six statements pertaining to workforce planning and management of communication and swallowing function in the ICU were included. SETTING: Electronic modified Delphi process. PARTICIPANTS: Speech-language pathologists (SLPs) (N=35) from 6 continents representing 12 countries. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: The main outcome was consensus agreement, defined a priori as ≥70% of participants with a mean Likert score ≥7.0 (11-point scale: 0=strongly disagree, 10=strongly agree). Prioritization rank order of statements in a fourth round was also conducted. RESULTS: SLPs with a median of 15 years of ICU experience, working primarily in clinical (54%), academic (29%), or managerial positions (17%), completed all voting rounds. After the third round, 64 statements (97%) met criteria. Rank ordering identified issues of high importance. CONCLUSIONS: A set of global consensus statements to facilitate planning and delivery of rehabilitative care for patients admitted to the ICU during the COVID-19 pandemic were agreed by an international expert SLP group. Statements focused on considerations for workforce preparation, resourcing and training, and the management of communication and swallowing functions. These statements support and provide direction for all members of the rehabilitation team to use for patients admitted to the ICU during a global pandemic.

Moving Forward with Dysphagia Care: Implementing Strategies during the COVID-19 Pandemic and Beyond.

Growing numbers of SARS-CoV-2 cases coupled with limited understanding of transmissibility and virulence, have challenged the current workflow and clinical care pathways for the dysphagia provider. At the same time, the need for non-COVID-19-related dysphagia care persists. Increased awareness of asymptomatic virus carriers and variable expression of the disease have also focused attention to appropriate patient care in the context of protection for the healthcare workforce. The objective of this review was to create a clinical algorithm and reference for dysphagia clinicians across clinical settings to minimize spread of COVID-19 cases while providing optimal care to patients suffering from swallowing disorders. Every practitioner and healthcare system will likely have different constraints or preferences leading to the utilization of one technique over another. Knowledge about this pandemic increases every day, but the algorithms provided here will help in considering the best options for proceeding with safe and effective dysphagia care in this new era.

COVID-19 survivorship: How otolaryngologist-head and neck surgeons can restore quality of life after critical illness.

Mortality from COVID-19 has obscured a subtler crisis - the swelling ranks of COVID-19 survivors. After critical illness, patients often suffer post-intensive care syndrome (PICS), which encompasses physical, cognitive, and/or mental health impairments that are often long-lasting barriers to resuming a meaningful life. Some deficits after COVID-19 critical illness will require otolaryngologic expertise for years after hospital discharge. There are roles for all subspecialties in preventing, diagnosing, or treating sequelae of COVID-19. Otolaryngologist leadership in multidisciplinary efforts ensures coordinated care. Timely tracheostomy, when indicated, may shorten the course of intensive care unit stay and thereby potentially reduce the impairments associated with PICS. Otolaryngologists can provide expertise in olfactory disorders; thrombotic sequelae of hearing loss and vertigo; and laryngotracheal injuries that impair speech, voice, swallowing, communication, and breathing. In the aftermath of severe COVID-19, otolaryngologists are poised to lead efforts in early identification and intervention for impairments affecting patients' quality of life.

Society of Critical Care Medicine's International Consensus Conference on Prediction and Identification of Long-Term Impairments After Critical Illness.

BACKGROUND: After critical illness, new or worsening impairments in physical, cognitive, and/or mental health function are common among patients who have survived. Who should be screened for long-term impairments, what tools to use, and when remain unclear. OBJECTIVES: Provide pragmatic recommendations to clinicians caring for adult survivors of critical illness related to screening for postdischarge impairments. PARTICIPANTS: Thirty-one international experts in risk-stratification and assessment of survivors of critical illness, including practitioners involved in the Society of Critical Care Medicine's Thrive Post-ICU Collaboratives, survivors of critical illness, and clinical researchers. DESIGN: Society of Critical Care Medicine consensus conference on post-intensive care syndrome prediction and assessment, held in Dallas, in May 2019. A systematic search of PubMed and the Cochrane Library was conducted in 2018 and updated in 2019 to complete an original systematic review and to identify pre-existing systematic reviews. MEETING OUTCOMES: We concluded that existing tools are insufficient to reliably predict post-intensive care syndrome. We identified factors before (e.g., frailty, preexisting functional impairments), during (e.g., duration of delirium, sepsis, acute respiratory distress syndrome), and after (e.g., early symptoms of anxiety, depression, or post-traumatic stress disorder) critical illness that can be used to identify patients at high-risk for cognitive, mental health, and physical impairments after critical illness in whom screening is recommended. We recommend serial assessments, beginning within 2-4 weeks of hospital discharge, using the following screening tools: Montreal Cognitive Assessment test; Hospital Anxiety and Depression Scale; Impact of Event Scale-Revised (post-traumatic stress disorder); 6-minute walk; and/or the EuroQol-5D-5L, a health-related quality of life measure (physical function). CONCLUSIONS: Beginning with an assessment of a patient's pre-ICU functional abilities at ICU admission, clinicians have a care coordination strategy to identify and manage impairments across the continuum. As hospital discharge approaches, clinicians should use brief, standardized assessments and compare these results to patient's pre-ICU functional abilities ("functional reconciliation"). We recommend serial assessments for post-intensive care syndrome-related problems continue within 2-4 weeks of hospital discharge, be prioritized among high-risk patients, using the identified screening tools to prompt referrals for services and/or more detailed assessments.

What Now for Rehabilitation Specialists? Coronavirus Disease 2019 Questions and Answers.

Recognizing a need for more guidance on the coronavirus disease 2019 (COVID-19) pandemic, members of the Archives of Physical Medicine and Rehabilitation Editorial Board invited several clinicians with early experience managing the disease to collaborate on a document to help guide rehabilitation clinicians in the community. This consensus document is written in a "question and answer" format and contains information on the following items: common manifestations of the disease; rehabilitation recommendations in the acute hospital setting, recommendations for inpatient rehabilitation and special considerations. These suggestions are intended for use by rehabilitation clinicians in the inpatient setting caring for patients with confirmed or suspected COVID-19. The text represents the authors' best judgment at the time it was written. However, our knowledge of COVID-19 is growing rapidly. The reader should take advantage of the most up-to-date information when making clinical decisions.

Clinical Decision Making in the ICU: Dysphagia Screening, Assessment, and Treatment.

Clinicians often perceive the intensive care unit as among the most intimidating environments in patient care. With the proper training, acquisition of skill, and approach to clinical care, feelings of intimidation may be overcome with the great rewards this level of care has to offer. This review-spanning the ages of birth to senescence and covering oral/nasal endotracheal intubation and tracheostomy-presents a clinically relevant, directly applicable review of screening, assessment, and treatment of dysphagia in the patients who are critically ill for clinical speech-language pathologists and identifies gaps in the clinical peer-reviewed literature for researchers.

Laryngeal Injury and Upper Airway Symptoms After Oral Endotracheal Intubation With Mechanical Ventilation During Critical Care: A Systematic Review.

OBJECTIVES: To systematically review the symptoms and types of laryngeal injuries resulting from endotracheal intubation in mechanically ventilated patients in the ICU. DATA SOURCES: PubMed, Embase, CINAHL, and Cochrane Library from database inception to September 2017. STUDY SELECTION: Studies of adult patients who were endotracheally intubated with mechanical ventilation in the ICU and completed postextubation laryngeal examinations with either direct or indirect visualization. DATA EXTRACTION: Independent, double-data extraction and risk of bias assessment followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Risk of bias assessment followed the Cochrane Collaboration's criteria. DATA SYNTHESIS: Nine studies (seven cohorts, two cross-sectional) representing 775 patients met eligibility criteria. The mean (SD; 95% CI) duration of intubation was 8.2 days (6.0 d; 7.7-8.7 d). A high prevalence (83%) of laryngeal injury was found. Many of these were mild injuries, although moderate to severe injuries occurred in 13-31% of patients across studies. The most frequently occurring clinical symptoms reported post extubation were dysphonia (76%), pain (76%), hoarseness (63%), and dysphagia (49%) across studies. CONCLUSIONS: Laryngeal injury from intubation is common in the ICU setting. Guidelines for laryngeal assessment and postextubation surveillance do not exist. A systematic approach to more robust investigations could increase knowledge of the association between particular injuries and corresponding functional impairments, improving understanding of both time course and prognosis for resolution of injury. Our findings identify targets for future research and highlight the long-known, but understudied, clinical outcomes from endotracheal intubation with mechanical ventilation in ICU.

Coordination of Pharyngeal and Laryngeal Swallowing Events During Single Liquid Swallows After Oral Endotracheal Intubation for Patients with Acute Respiratory Distress Syndrome.

To evaluate timing and duration differences in airway protection and esophageal opening after oral intubation and mechanical ventilation for acute respiratory distress syndrome (ARDS) survivors versus age-matched healthy volunteers. Orally intubated adult (≥ 18 years old) patients receiving mechanical ventilation for ARDS were evaluated for swallowing impairments via a videofluoroscopic swallow study (VFSS) during usual care. Exclusion criteria were tracheostomy, neurological impairment, and head and neck cancer. Previously recruited healthy volunteers (n = 56) served as age-matched controls. All subjects were evaluated using 5-ml thin liquid barium boluses. VFSS recordings were reviewed frame-by-frame for the onsets of 9 pharyngeal and laryngeal events during swallowing. Eleven patients met inclusion criteria, with a median (interquartile range [IQR]) intubation duration of 14 (9, 16) days, and VFSSs completed a median of 5 (4, 13) days post-extubation. After arrival of the bolus in the pharynx, ARDS patients achieved maximum laryngeal closure a median (IQR) of 184 (158, 351) ms later than age-matched, healthy volunteers (p < 0.001) and it took longer to achieve laryngeal closure with a median (IQR) difference of 151 (103, 217) ms (p < 0.001), although there was no significant difference in duration of laryngeal closure. Pharyngoesophageal segment opening was a median (IQR) of - 116 (- 183, 1) ms (p = 0.004) shorter than in age-matched, healthy controls. Evaluation of swallowing physiology after oral endotracheal intubation in ARDS patients demonstrates slowed pharyngeal and laryngeal swallowing timing, suggesting swallow-related muscle weakness. These findings may highlight specific areas for further evaluation and potential therapeutic intervention to reduce post-extubation aspiration.

Electromyography of Swallowing with Fine Wire Intramuscular Electrodes in Healthy Human: Amplitude Difference of Selected Hyoid Muscles.

Few studies have examined the intensity of muscle activity during swallowing in healthy humans. We examined selected hyoid muscles using fine wire intramuscular electromyography (EMG) during swallowing of four food consistencies. Thirteen healthy adults were studied using videofluorography and EMG of the anterior belly of digastric (ABD), geniohyoid (GH), sternohyoid (SH), and masseter (MA; surface electrodes) while ingesting thin liquid (three trials) and solid food of three consistencies (banana, tofu, and cookie, three trials each). After rectification, integration, and normalization, peak EMG amplitudes for each muscle in each trial were measured. Hyoid displacements were measured in two dimensions. Data were analyzed using repeated measures ANOVA with Bonferroni correction. GH had the highest adjusted amplitude for both solids and liquid. For MA and ABD, amplitude was highest with triturated cookie. For ABD, amplitude was lowest with liquid. There were no significant food consistency effects for GH or SH. Hyoid displacements were greatest for cookie and the lowest for liquid. EMG amplitude varied with initial food consistency. The high peak EMG amplitude of GH is consistent with its essential role in opening the upper esophageal sphincter. High MA amplitude with hard solid foods is likely due to the higher tongue-palate pressure with triturated solids. The higher ABD amplitude with solid food is associated with greater hyoid displacement. These findings support the existence of a central pattern generator that modifies the level of muscle activity during pharyngeal swallowing in response to input from mechanoreceptors in the oral cavity.