Korean J Otolaryngol-Head Neck Surg.  2004 Dec;47(12):1230-1235.

Significance of Lying-Down Nystagmus in the Lateralization of Lateral Canal Benign Paroxysmal Positional Vertigo

• Koo JW
• Moon IJ
• Shim WS
• Yoo JY
• Moon SY
• Kim JS

Abstract

BACKGROUND AND OBJECTIVES
Lateral canal benign paroxysmal positional vertigo (LC-BPPV) is characterized by horizontal direction changing nystagmus induced by lateral head turning in supine position. According to the Ewald's second law, the direction of head turning that creates stronger response represents the affected side of geotropic nystagmus and the healthy side in apogeotropic nystagmus. However, it may not always be possible to lateralize the involved ear only by comparing the intensity of the nystagmus. We studied the values of lying-down nystagmus (LDN) in the lateralization of LC-BPPV. SUBJECTS AND METHOD: We performed a retrospective study of 54 patients who had been diagnosed as having LC-BPPV in Dizziness Clinic of Seoul National University Bundang Hospital from May 2003 to February 2004. The directions of the nystagmus induced by lying down were compared with those determined by the Ewald's second law. RESULTS: Of the 54 patients, 32 (20 apogeotropic and 12 geotropic) patients showed horizontal nystagmus induced by lying down. The nystagmus was ipsilesional in 16 (80%) apogeotropic and contralesional in 9 (75%) geotropic patients. CONCLUSION: In LC-BPPV, the LDN mostly beats toward the involved ear in the apogeotropic type, and directs to the healthy ear in the geotropic type. The direction of LDN may help lateralizing the involved ear in LC-BPPV

Keyword

Positional vertigo; Semicircular canal (lateral); Nystagmus

MeSH Terms

Deception
Dizziness
Ear
Head
Humans
Jurisprudence
Nystagmus, Pathologic
Retrospective Studies
Seoul
Supine Position
Vertigo*