Criteria	Bulbar Palsy	Pseudobulbar Palsy
1. Type of lesion	LMN	UMN
2. Site of lesion	Medulla	Bilateral, internal capsule
3. Speech	Nasal	Slow, slurred and indistinct
4. Nasal regurgitation	Present	Absent
5. Tongue	Wasted, fasciculation	Small, stiff or spastic
6. Jaw jerk	Absent	Brisk
7. Emotion	Normal	Labile

• Bulbar palsy is a lower motor neuron palsy that affects the nuclei of the IX^th, X^th, XI^th, and XII^th cranial nerves.
• Pseudobulbar palsy is an upper motor neuron palsy that affects the corticobulbar tracts of the V^th, VII^th, IX^th, X^th, XI^th, and XII^th cranial nerves.

Bulbar palsy

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Etiology

• Brainstem stroke or tumors
• Neurodegenerative diseases: amyotrophic lateral sclerosis, syringobulbia
• Autoimmune neuropathies: Guillain-Barré syndrome, myasthenia gravis
• Infectious neuropathies: poliomyelitis, diphtheria, neurosyphilis

Pathophysiology

• Bilateral damage or injury of the nerve nuclei of cranial nerves IX, X, XI, and XII
  • Since the cranial nerve nuclei in the brain stem are paired, unilateral lesions are often asymptomatic.
• Lower motor neuron palsy of the respective muscles

Clinical features

• Facial expression: normal
  • Sparing of the VII^th cranial nerve nucleus
• Speech: nasal
  • Due to paresis of the palate as well as of the tongue and lips
• Dysphagia, drooling, nasal regurgitation
• Tongue
  • Wasting
  • Fasciculations
  • Inability to protrude the tongue
• Palatal movement: absent
• Gag reflex: absent
• Jaw jerk: normal
• Emotions not affected

Pseudobulbar palsy

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Etiology

• Stroke (multiple, recurrent strokes)
• Neurodegenerative disease: amyotrophic lateral sclerosis, progressive supranuclear palsy, multiple sclerosis

Pathophysiology

• Bilateral damage or injury of corticobulbar tracts to nerve nuclei of cranial nerves V, VII, IX, X, XI, and XII
  • Note that the cranial nerves V and VII are involved in pseudobulbar palsy, but not in bulbar palsy.
• Upper motor neuron palsy of the respective muscles

Clinical features

• Facial expressions: absent (expressionless face)
  • Due to VIIth nerve involvement
• Speech: spastic dysarthria (husky, nasal voice)
• Difficulty in chewing
  • Vth nerve palsy → paralysis of the muscles of mastication
• Dysphagia, drooling, and nasal regurgitation
• Tongue
  • Spastic, pointed
  • Difficulty in tongue protrusion due to spasticity
  • No wasting/fasciculations
• Palatal movement: absent
• Gag reflex: brisk (exaggerated)
• Jaw jerk: exaggerated; clonic
  • Upper motor neuron palsy of Vth cranial nerve → exaggerated jaw jerk.
• Emotional incontinence (pseudobulbar affect)
  • Disruption of central serotonin and dopamine pathways → social disinhibition → uncontrolled and/or mood-incongruent laughing and crying