Nystagmus in patients with lateral semicircular canal dysplasia

Acta Otolaryngol. 2020 Dec;140(12):971-976. doi: 10.1080/00016489.2020.1804615. Epub 2020 Aug 18.


Background: Dizziness is not a common symptom in the lateral semicircular canal (LSCC) dysplasia, and nystagmus findings has been rarely described in LSCC dysplasia.

Objective: To investigate the characteristics of spontaneous and positional nystagmus in patients with LSCC dysplasia.

Methods: Patterns of spontaneous and positional nystagmus of twelve patients with LSCC dysplasia, who visited our clinic with a chief complaint of dizziness, were investigated.

Results: LSCC dysplasia was observed unilaterally in 4, and bilaterally in 8 patients. Non-rotatory dizziness with various onset times was the most common description of dizziness, and unilateral caloric weakness was observed in 82% of patients. Direction-fixed nystagmus, in which the direction of spontaneous nystagmus was same with that of positional nystagmus, was observed in 9 patients, and direction-changing positional nystagmus, in which the direction of nystagmus was changed from that of spontaneous nystagmus by positioning maneuvers, was observed in 3 patients, of whom down-beating or direction-changing spontaneous nystagmus was observed in one patient each.

Conclusion: While direction-fixed horizontal nystagmus is the most commonly observed type of nystagmus in LSCC dysplasia, atypical spontaneous nystagmus, such as down-beating nystagmus or direction-changing spontaneous nystagmus, may be observed in patients with bilateral LSCC dysplasia.

Keywords: Lateral semicircular canal dysplasia; dizziness; inner ear anomaly; nystagmus.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Dizziness / etiology
  • Female
  • Humans
  • Male
  • Middle Aged
  • Nystagmus, Pathologic / etiology*
  • Nystagmus, Pathologic / physiopathology
  • Retrospective Studies
  • Semicircular Canals / abnormalities*
  • Semicircular Canals / diagnostic imaging
  • Semicircular Canals / physiopathology
  • Temporal Bone / diagnostic imaging
  • Vertigo / etiology