What could be causing difficulty in yawning in a patient with potential underlying neurological disorders, such as Parkinson's disease (PD) or multiple sclerosis (MS), and how can it be managed?

Difficulty in Yawning: Neurological Causes and Management

Primary Recommendation

Difficulty in yawning in patients with Parkinson's disease or multiple sclerosis likely reflects dysfunction in the brainstem motor pattern generators and hypothalamic paraventricular nucleus that control this stereotyped reflex, and should prompt comprehensive neurological evaluation to assess disease progression and associated bulbar symptoms. 1

Understanding the Mechanism

Yawning is a phylogenetically preserved reflex controlled by a distributed brain network including:

• Brainstem motor pattern generators that execute the stereotyped motor sequence 1
• Hypothalamic paraventricular nucleus that initiates the reflex 1
• Limbic structures and insula that modulate the behavior 1
• Interconnecting fiber tracts that coordinate these regions 1

When patients report difficulty yawning, this indicates disruption somewhere within this network—either from direct lesions, disconnection syndromes, or altered network activity from metabolic/medication effects 1.

Neurological Conditions Associated with Abnormal Yawning

Parkinson's Disease

• Hypophonia and reduced vocal intensity are hallmark features that may coexist with difficulty yawning, both reflecting brainstem and basal ganglia dysfunction 2, 3
• The same extrapyramidal pathology affecting voluntary movement impairs the coordinated motor sequence required for yawning 2
• Patients may also exhibit monotone speech and breathy phonation from glottal insufficiency 2

Multiple Sclerosis

• Brainstem demyelination can directly damage the yawning network 4
• MS patients with dysphagia (34% in progressive forms) often have severe brainstem impairment that could simultaneously affect yawning mechanisms 5
• Cerebellar involvement increases risk of bulbar dysfunction 5

Other Neurological Associations

• Stroke affecting brainstem or hypothalamic regions 4
• Brain tumors, particularly those compressing brainstem structures or located in temporal regions 4, 6
• Amyotrophic lateral sclerosis with bulbar involvement 4
• Chiari malformation type I causing posterior fossa compression 4

Critical Diagnostic Approach

Red Flags Requiring Immediate Escalation

Evaluate for these concurrent symptoms that indicate serious underlying pathology:

• Dysarthria and dysphagia with or without aspiration—may indicate amyotrophic lateral sclerosis or progressive bulbar palsy 5
• Upper motor neuron signs combined with bulbar symptoms 5
• Hoarseness with neurologic symptoms—warrants expedited laryngeal examination 5
• Progressive symptoms suggesting advancing neurological disease 5
• Respiratory distress requiring immediate escalated care 5

Specific Examination Elements

Document the following:

• Brainstem function: Test cranial nerves V, VII, IX, X, XII for bulbar involvement 5
• Cerebellar signs: Ataxia, dysmetria, intention tremor 5
• Extrapyramidal features: Rigidity, bradykinesia, tremor 2
• Vocal quality: Assess for hypophonia, monotone speech, breathy phonation 2, 3
• Swallowing function: Screen with validated tools like DYMUS questionnaire for MS patients 5

Laryngoscopy Indications

Visualize the larynx within 4 weeks if difficulty yawning accompanies hoarseness or dysphonia, or immediately if serious underlying cause suspected 5:

• Hoarseness with neurologic symptoms 5
• Concurrent dysphagia or aspiration 5
• Progressive bulbar symptoms 5
• History suggesting recurrent laryngeal nerve injury 5

Management Strategy

For Parkinson's Disease Patients

Initiate Lee Silverman Voice Treatment (LSVT LOUD®) as the most effective specialized therapy for associated hypophonia and bulbar dysfunction 3:

• Consists of 1-2 sessions weekly for 4-8 weeks with certified speech-language pathologists 3
• Addresses behavioral and muscular issues contributing to bulbar symptoms 3
• May combine with botulinum toxin for coexisting spasmodic dysphonia or tremor 3
• Maintain adequate hydration for vocal fold health 3

For Multiple Sclerosis Patients

Screen for dysphagia using DYMUS questionnaire, as 31% of MS patients have abnormal results and difficulty yawning may herald swallowing dysfunction 5:

• Perform FEES (fiberoptic endoscopic evaluation of swallowing) if screening positive 5
• Modify food and fluid consistency according to individualized swallowing assessment 5
• Consider PEG tube placement if unable to meet nutritional needs orally 5
• Implement behavioral swallowing therapy per general dysphagic patient guidelines 5

Medication Review

Evaluate for drug-induced effects:

• SSRIs, TCAs, MAOIs can alter yawning patterns 5, 7
• Inhaled corticosteroids, antihistamines, diuretics, anticholinergics cause mucosal drying affecting bulbar function 2
• Consider medication adjustment if temporal relationship exists 5

Common Pitfalls to Avoid

• Do not dismiss difficulty yawning as trivial—it may represent early brainstem or hypothalamic pathology requiring neuroimaging 1, 4
• Do not delay laryngoscopy in patients with concurrent hoarseness and neurologic symptoms, as this may indicate vocal fold paralysis or progressive bulbar disease 5
• Do not overlook dysphagia screening in MS and PD patients reporting difficulty yawning, as both reflect overlapping brainstem dysfunction 5
• Do not attribute symptoms solely to psychiatric causes without excluding organic pathology, particularly in patients with systemic symptoms 7

When to Refer

Refer to neurology immediately if:

• Progressive bulbar symptoms with dysarthria, dysphagia, and difficulty yawning 5
• New-onset neurologic signs suggesting brainstem or hypothalamic lesion 1, 4
• Concern for amyotrophic lateral sclerosis or other motor neuron disease 5, 4

Refer to otolaryngology if:

• Concurrent hoarseness persisting beyond 3 months or with red flag features 5
• Professional voice users with vocal concerns 5
• Need for laryngoscopy to assess vocal fold function 5