Multiple Sclerosis and Dysphagia: Fatigue, Relapse and Swallowing Management

Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system affecting approximately 2.8 million people worldwide. While dysphagia is less frequently emphasised than other MS symptoms such as fatigue, spasticity, and visual disturbance, it affects 30–40% of people with MS at some point in their illness and can have serious consequences when under-recognised.

The nature of dysphagia in MS is strongly shaped by two defining disease characteristics: the relapsing-remitting course in most patients and the profound fatigue that affects 80% of MS patients regardless of disease type.

This article follows ASHA Practice Portal guidance on adult dysphagia and NICE CG162.

Prevalence and Clinical Pattern

Dysphagia in MS is most common in:

• Secondary progressive MS (more common as disease advances and brainstem lesion load accumulates)
• Primary progressive MS (brainstem and corticobulbar tract involvement from onset)
• Brainstem relapse in relapsing-remitting MS (sudden onset dysphagia during relapse)
• High cervical cord lesions (affecting proprioceptive feedback to swallowing musculature)

Mild, subclinical dysphagia on instrumental assessment is more common than clinically evident swallowing complaints, reflecting the partial compensation that characterises MS disease. Patients may not report dysphagia unless specifically asked, and even then may attribute their symptoms to fatigue rather than a swallowing disorder per se.

Neurological Mechanisms

Corticobulbar Tract Demyelination

Bilateral corticobulbar tract involvement — common in progressive MS — produces pseudobulbar palsy: spastic dysarthria, hyper-reflexive gag, emotional lability, and impaired voluntary control of oral and pharyngeal phases. Swallowing under voluntary control (e.g., swallowing on command during assessment) may be more impaired than automatic swallowing during natural eating.

Brainstem Demyelination

Lesions in the medulla, pons or cerebellum directly affect swallowing CPG function, cranial nerve nuclei, and the cerebellar circuits that coordinate tongue–pharyngeal timing. Cerebellar involvement specifically produces dysmetric (uncoordinated) swallowing patterns with irregular timing and variable amplitude of pharyngeal constriction.

Fatigue and Swallowing

MS fatigue is neurological in origin — partly reflecting conduction slowing in demyelinated axons and partly impaired central motor drive. Its impact on swallowing is clinically important but underrecognised:

• Swallowing performance deteriorates over the course of a meal in MS patients with fatigue
• Aspiration may occur only in the second half of a meal, after oral and pharyngeal muscles have fatigued
• Standard bolus assessments conducted on a single bolus (as in VFSS) may miss fatigue-related deterioration

A comprehensive assessment should therefore include observation across a full meal or at minimum multiple swallow trials to elicit fatigue effects. This point is emphasised in ASHA Practice Portal recommendations for fatigue-sensitive conditions.

Relapse and Dysphagia

In relapsing-remitting MS, acute brainstem or corticobulbar relapses can cause sudden-onset dysphagia. Importantly, dysphagia may be the first or only symptom of a brainstem relapse — a patient presenting with sudden swallowing difficulty warrants neurological review for acute demyelination.

During relapse:

• Dysphagia severity often worsens acutely before recovering over weeks to months with standard relapse treatment (intravenous corticosteroids)
• SLT review should be requested for all patients with confirmed brainstem relapse
• Temporary IDDSI modification may be required during the acute phase

After relapse:

• Re-assessment of swallowing function when the relapse has resolved — the IDDSI prescription appropriate during a relapse may no longer be needed afterwards
• Some residual dysphagia may persist after incomplete relapse recovery

Assessment

Clinical swallowing assessment in MS should include:

• Oral mechanism examination — assess tongue strength and coordination, labial function, palatal elevation
• Voice quality — wet or gurgly voice suggests laryngeal pooling
• Cough reflex — assess with cough on command and spontaneous cough response to small water bolus
• Fatigue assessment — Modified Fatigue Impact Scale (MFIS) to quantify fatigue severity; conduct swallow assessment at the patient’s worst fatigue time if possible
• Instrumental assessment (VFSS or FEES) — recommended for all MS patients with clinically significant swallowing complaints, wet voice, recurrent chest infections, or weight loss

Prof. Karen Chan’s group at the HKU Swallowing Research Lab has noted that swallowing fatigue effects are inadequately captured by single-trial videofluoroscopy and has advocated for multiple-swallow paradigms in the instrumental assessment of fatigue-related conditions including MS.

Management

IDDSI Texture Modification

Where aspiration of specific bolus consistencies is confirmed, the IDDSI framework guides appropriate modification. For MS patients, the IDDSI level may need to be different at different times of day (stricter in the afternoon when fatigue is highest; more liberal in the morning after rest).

Energy Conservation at Mealtimes

• Short meals with rest breaks rather than prolonged single sittings
• Fortified, energy-dense foods to maximise nutritional intake per swallow effort
• Main meal at the most energetic time of day — typically mid-morning or early afternoon in most MS patients
• Positioning support — adequate seating support reduces postural fatigue that compounds swallowing fatigue

Swallowing Rehabilitation

Swallowing exercises should be adapted for MS fatigue:

• Fewer repetitions, more frequent sessions rather than long single sessions
• Activity scheduling — not immediately before or after peak fatigue periods
• Some evidence for effortful swallow and Mendelsohn manoeuvre in MS, consistent with their use in other neurogenic dysphagia

Monitoring for Relapse

Caregivers and patients should be educated to recognise sudden changes in swallowing function as a potential relapse sign requiring neurological review, not simply managed with dietary modification alone.

When to Refer

Any MS patient with coughing during meals, wet voice, recurrent chest infections, or progressive weight loss should be referred for SLT assessment. Sudden worsening of swallowing function requires urgent neurological review to exclude brainstem relapse. See When to Refer to a Speech and Language Therapist.

References

1. American Speech-Language-Hearing Association. Adult Dysphagia Practice Portal. https://www.asha.org/practice-portal/clinical-topics/adult-dysphagia/
2. National Institute for Health and Care Excellence. Stroke Rehabilitation in Adults (CG162). https://www.nice.org.uk/guidance/cg162
3. IDDSI. The IDDSI Framework. https://www.iddsi.org/framework
4. Logemann JA, et al. (2015). Disorders of deglutition. Handbook of Clinical Neurology, 129, 465–487. PMID: 26315994