MuScle WastIng and DysphaGia iN CriticAlly IlL Patients (SIGNAL) (SIGNAL)

The Relationship Between Oral and Suprahyoid Muscle Wasting and Dysphagia in Critically Ill Patients

The goal of this study is to find out how muscle wasting in the mouth and throat affects swallowing (dysphagia) in adults who are critically ill and being treated in intensive care units.

The main aims of this research study are to understand: how much and how quickly the oral and suprahyoid muscles waste in critically ill participants, and whether muscle wasting causes problems with swallowing. The investigators will compare critically ill participants with non-critically ill participants to determine if muscle wasting is linked to swallowing problems.

In this study, participants will have the size and strength of their mouth and throat muscles measured at four different times during their critical care admission and hospital stay. Tests will also be performed to check how well and how safely participants can swallow. Tongue strength will be measured, and participants will answer questions about their experience with swallowing and eating using patient-reported outcome measures.

This study may help identify better ways to diagnose and treat swallowing problems in people who are critically ill, to support safe eating and drinking and promote faster recovery.

Study Overview

• Status: Recruiting
• Conditions: Critical Illness; Dysphagia; Swallowing Disorders; Muscle Wasting in Critically Ill

Detailed Description

Background:

Dysphagia is a common and serious complication among critically ill patients admitted to intensive care units (ICUs). Up to 62% of patients who require mechanical ventilation experience dysphagia, which can lead to aspiration pneumonia, malnutrition, longer hospital stays, and increased mortality. Muscle wasting is a known consequence of critical illness and is associated with poor functional outcomes. The contribution of oral and suprahyoid muscle wasting to dysphagia in critically ill participants is poorly understood. This study aims to prospectively evaluate muscle wasting and its impact on swallowing function in critically ill adults.

Ethical Approval:

This study has Research Ethics Committee and Health Research Authority approval.

Study Objectives:

Primary Objective:

To measure the extent and rate of change in the cross-sectional area of the oral and suprahyoid muscles in critically ill adults using bedside ultrasound at four time points, and to relate these changes to swallowing physiology and safety.

Secondary Objectives:

To compare muscle mass and swallowing function between critically ill and non-critically ill participants.

To measure electrophysiological features of swallowing muscles using high-definition surface electromyography.

To assess patient-reported outcomes related to swallowing and eating.

To compare changes in the rectus femoris (thigh) muscle to those in the oral and suprahyoid muscles as a reference for general muscle wasting.

Study Design:

This is a prospective observational study. Critically ill participants admitted to the ICU will be recruited and compared with non-critically ill controls. The study includes repeated measures of muscle size and swallowing function over time.

Study Procedures:

Ultrasound Assessments:

The cross-sectional area of the tongue, geniohyoid, mylohyoid, and anterior belly of digastric muscles will be measured using bedside ultrasound at four time points during the participant's ICU stay. The rectus femoris muscle will also be measured as a reference for general muscle wasting.

Swallowing Evaluation:

Instrumental assessments of swallowing physiology and safety will be performed using gold standard assessments (e.g., videofluoroscopy or fiberoptic endoscopic evaluation of swallowing).

Tongue Strength:

Tongue strength will be measured using tongue dynamometry.

Electromyography:

High-definition surface electromyography will assess muscle activation patterns at rest and during swallowing.

Patient-Reported Outcomes:

Participants will complete patient reported outcome measures on swallowing, eating, and quality of life.

Data Management and Quality Assurance:

Data will be collected and managed according to Good Clinical Practice (GCP) and UK data protection regulations. Data will be collected using an online database (RedCap). Monitoring and auditing will be conducted by the sponsor to ensure protocol adherence and data integrity.

Sample Size and Statistical Analysis:

The sample size is calculated to detect clinically meaningful differences in muscle wasting and swallowing outcomes, based on expected rates in critically ill patients. Sample size was calculated based on a proof-of-conduct study completed by the investigators.

The primary analysis will use mixed-effects models to evaluate changes in muscle size and their association with swallowing function over time. Secondary analyses will compare critically ill patients with non-critically ill controls and explore associations between muscle wasting, swallowing outcomes, and patient-reported measures. Missing data will be addressed using appropriate statistical methods, such as multiple imputation or sensitivity analyses, as detailed in the statistical analysis plan.

Safety and Adverse Event Reporting:

The study involves only non-invasive assessments; risks are minimal and mainly relate to patient discomfort during swallowing tests. Adverse events and serious adverse events will be monitored and reported according to regulatory requirements.

Patient and Public Involvement:

Patients with experience of dysphagia in critical care contributed to the design of the study and the selection of outcome measures.

• Study Type: Observational
• Enrollment (Estimated): 160

Contacts and Locations

Study Locations

• United Kingdom
  • London, United Kingdom, E1 1FR
    • Recruiting
    • Royal London Hospital
    • Contact: Eileen Kelly; Phone Number: +44 (0)20 3594 0351; Email: eileen.kelly3@nhs.net

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

Critically ill patients and non-critically ill patients

Description

Inclusion Criteria:

• Adults >18 years
• Receiving mechanical ventilation via endotracheal tube and/or tracheostomy. Expected to receive ventilation for at least 72 hours.
• Expected to survive admission and spend more than 7 days in the intensive care unit.

Control participants

• Adults >18 years
• Receiving ward-based care.
• Expected to survive hospital admission. Present with a primary medical diagnosis of acute medical or surgical illness, not requiring critical care admission.

Exclusion Criteria:

Applies to both critically ill and control participants.

• Pregnancy
• Patients with a diagnosis of a primary neuromuscular pathology (e.g., motor neurone disease), central nervous system disease (e.g., stroke, Guillain barre), traumatic brain injury, connective tissue disease (e.g., scleroderma), head and neck cancer, previous surgery or radiotherapy to the head and neck.

Study Plan

How is the study designed?

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Measure the extent and rate of muscle wasting	To measure the extent and rate of change in cross-sectional area of the oral and suprahyoid muscles in critically ill adults using bedside ultrasound across four time points. The extent and rate of muscle wasting will be assessed by measuring the change in cross-sectional area (mm²) of the oral and suprahyoid muscles using bedside ultrasound.	Day 1, 3, 7 and 10 of intensive care unit admission
Relate muscle wasting to swallow physiology and safety	To correlate changes in cross-sectional area to swallow physiology and safety in critically ill patients, using instrumental swallowing evaluations and tongue strength. To quantify the change in size of the oral and suprahyoid muscles, the cross-sectional area (mm²) will be measured using bedside ultrasound. Swallowing physiology and safety will be assessed using instrumental swallowing evaluations (e.g., Fiberoptic Endoscopic Evaluation of Swallowing (FEES)).The correlation coefficient (e.g., Pearson's or Spearman's r) between ultrasound-measured muscle cross-sectional area and instrumental swallowing assessment scores (e.g., the Penetration Aspiration Scale) will be used.	Following day 10 ultrasound or when the patient is extubated and clinically appropriate for swallow assessment

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Measure electrophysiological features of swallow muscle activity	To measure the electrophysiological features of swallowing muscles using high definition surface electromyography in critically ill and non-critically ill patients. Electrophysiological features of swallowing-related muscles will be measured. Parameters will include average root mean square amplitude, symmetry of muscle activation, and duration of muscle activity during swallowing tasks.	Day 1, 3, 7 and 10 of intensive care unit admission
Compare relationship between muscle mass and swallow physiology	To compare the relationship between muscle mass and swallow physiology in critically ill patients and non-critically ill patients. The correlation between muscle mass and swallow physiology will be assessed. Muscle mass will be measured using ultrasound cross-sectional area (cm²) of the oral and suprahyoid muscles at four time points: Day 1, Day 3, Day 7, and Day 10 of ICU admission. Swallow physiology will be evaluated using instrumental evaluation (e.g., flexible endoscopic evaluation of swallow) and the following scales: Penetration-Aspiration Scale, Yale Pharyngeal Residue Severity Rating Scale and the Dynamic Imaging Grade of Swallow Toxicity) whichever occurs first, and when the patient is deemed clinically appropriate for assessment. The primary outcome will be the correlation coefficient (e.g., Pearson's or Spearman's r) between ultrasound-measured muscle mass (cm²) and swallow physiology scores.	Day 1, 3, 7 and 10 ultrasound assessments, swallow evaluation completed following day 10 ultrasound or when patient is extubated and clinically appropriate
Patient reported outcomes: Sydney Swallow Questionnaire	Patient-reported severity of dysphagia symptoms will be assessed using the Sydney Swallow Questionnaire (SSQ), with the total score ranging from 0 to 1700, where higher scores indicate greater symptom severity.	Within two weeks of day 10 ultrasound measurement or when clinically appropriate (e.g., ICU delirium resolved if present), up to 1 month
Patient reported outcomes: Swallowing Quality of Life (SWAL-QoL) Score	Patient-reported swallowing-related quality of life will be assessed using the Swallowing Quality of Life (SWAL-QoL) questionnaire, a 44-item instrument producing a total score from 0 to 100, where higher scores reflect better quality of life.	Within two weeks of day 10 ultrasound measurement or when clinically appropriate (e.g., ICU delirium resolved if present), up to 1 month
Patient reported outcomes: Functional Oral Intake Scale	Functional oral intake level will be measured using the Functional Oral Intake Scale (FOIS), a 7-point ordinal scale ranging from 1 (nothing by mouth) to 7 (total oral diet with no restrictions), where higher scores represent greater functional intake.	Within two weeks of day 10 ultrasound measurement or when clinically appropriate (e.g., ICU delirium resolved if present), up to 1 month
Patient reported outcomes: Eating Assessment Tool-10 (EAT-10)	Patient-reported dysphagia symptom burden will be screened using the Eating Assessment Tool-10 (EAT-10), a 10-item instrument with total scores ranging from 0 to 40, where scores of 3 or higher suggest abnormal swallowing.	Within two weeks of day 10 ultrasound measurement or when clinically appropriate (e.g., ICU delirium resolved if present), up to 1 month
Compare the extent of muscle wasting in critically ill versus non-critically ill patient	To measure and compare the extent and rate of change in cross-sectional area of the rectus-femoris muscle and the oral and supra-hyoid muscles using bedside ultrasound across four time points.	Day 1, 3, 7 and 10 ultrasound evaluation vs single timepoint in non-critically ill patients

Collaborators and Investigators

• Sponsor: Barts & The London NHS Trust

Study record dates

Study Major Dates

• Study Start (Actual): August 1, 2025
• Primary Completion (Estimated): January 31, 2028
• Study Completion (Estimated): January 31, 2028

Study Registration Dates

• First Submitted: May 22, 2025
• First Submitted That Met QC Criteria: July 17, 2025
• First Posted (Actual): July 22, 2025

Study Record Updates

• Last Update Posted (Actual): November 18, 2025
• Last Update Submitted That Met QC Criteria: November 17, 2025
• Last Verified: November 1, 2025

More Information

Terms related to this study

• Keywords: critical illness; dysphagia; muscle wasting; swallowing disorders
• Additional Relevant MeSH Terms: Neurologic Manifestations; Nervous System Diseases; Neuromuscular Manifestations; Pathologic Processes; Pathological Conditions, Anatomical; Disease Attributes; Digestive System Diseases; Gastrointestinal Diseases; Esophageal Diseases; Otorhinolaryngologic Diseases; Pharyngeal Diseases; Atrophy; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Critical Illness; Deglutition Disorders; Muscular Atrophy
• Other Study ID Numbers: 348596; G-002784 (Other Grant/Funding Number: Barts Charity)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No