GENERAL NEUROLOGY

David Goldemund M.D.
Updated on 16/03/2024, published on 04/02/2024

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

• 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
  • infection (viral encephalitis)
  • polyradiculoneuritis (Landry’s ascending paralysis)
  • ischemia → vertebrobasilar stroke
  • tumors

• 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

• 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
    

• for example, extensive small vessel disease (often associated with prefrontal syndrome)
  • Binswanger disease 
  • Genetic small vessel diseases 
• initial stages of ALS (before bulbar syndrome occurs)
• primary lateral sclerosis (PLS)