GENERAL NEUROLOGY

Bulbar and pseudobulbar palsy

David Goldemund M.D.
Updated on 15/06/2024, published on 04/02/2024

Bulbar palsy

  • motor disorder, resulting from lesions of CN IX, X, XI (lateral system) and CN XII or their nuclei

Clinical Presentation

  • articulation disorder (dysarthria to anarthria, dysphonia)
  • dysphagia (liquids leaking through the nose when drinking, increased risk of aspiration)
  • drooping soft palate
  • atrophy and fasciculation of the tongue  Atrophic tongue in bulbar syndrome due to ALS (Toro, 2014)
  • hyporeflexia to areflexia of the gag reflex
  • decreased jaw jerk reflex
  • expansive processes may lead to lesions of centers controlling breathing, heart function, and vasomotor activity

Etiology

  • neurodegenerative diseases
    • progressive bulbar palsy (Duchenne)
    • amyotrophic lateral sclerosis (ALS)
    • syringomyelia
    • Kennedy’s disease (bulbospinal muscular atrophy) – bulbar syndrome, gynecomastia, hand tremor, muscle pains, and cramps
  • lesional disorders of the brainstem or cranial nerves

Pseudobulbar palsy

  • it results from bilateral involvement of the central motor pathways of the cranial nerves (corticobulbar tract)
    • unilateral lesions of the corticobulbar tract typically do not lead to significant impairment of the function of cranial nerves (as supranuclear innervation is ipsi- and contralateral)
    • a slight deviation of the tongue towards the side of limb paresis may be observed due to the dominance of the healthy genioglossus muscle
    • mild dysarthria may be present, often due to paresis of CN VII, but swallowing is generally unaffected

Clinical Presentation

  • motor dysfunction similar to that of bulbar palsy, but without tongue atrophy and fibrillations
  • ↑↑ masseter reflex (even presenting with clonus)
  • markedly positive axial signs
  • pseudobulbar affect (PBA), also known as emotional incontinence, is characterized by sudden and unpredictable episodes of involuntary crying or laughing that are often inappropriate to the social context   (Ahmed, 2013)
    • PSA is caused by a disconnection between the frontal lobe (which controls emotions) and the cerebellum and brainstem
  • monotonous or even aphonic speech
  • dysphagia
  • pyramidal or even extrapyramidal symptoms
    • “frontal gait” with bradybasia and brachybasia, resulting in postural instability and requiring assistance from another person to maintain balance

Etiology

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Bulbar and pseudobulbar palsy
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