Direction Changing Positional Nystagmus from Canalolithiasis and Cupulolithiasis of Lateral Semicircular Canal

Chung, Woon Kyo; Lee, Won Sang; Kim, Moon Suk; Lee, Joo Hwan; Lee, Sei Young

Abstract

BACKGROUND AND OBJECTIVES: Clinical features of positional nystagmus may be different according to the etiology. Thus, efforts have been made to find out etiologies of various positional nystagmus. Until recently, positional vertigo was thought to arise from lesions of central nervous system. However, more recent investigations suggest that the peripheral lesion may be the main cause. Moreover, there have been some reports suggesting that directional changing positional nystagmus occurs due to canalolithiasis and cupulolithiasis of the lateral semicircular canal. The objectives of the study were to investigate the etiologies and clinical aspects of DCPN (direction changing positional nystagmus) from canalolithiasis and cupulolithiasis of the lateral semicircular canal, and to assess the effectiveness of the treatment.
MATERIALS AND METHODS
Among 15 patients with DCPN, 9 patients showed nystagmus compatible with canalolithiasis of lateral semicircular canal and 6 patients with cupulolithiasis of lateral semicircular canal. Patients with cupulolithiasis and canalithiasis of the lateral semicircular canal did not respond to physical therapy for posterior semicircular canal. However, they were completely recovered by reposition maneuver for the lateral semicircular canal with or without using vibrator although 3 of them had recurred symptom. Four patients had BPPV of the posterior semicircular canal prior to the development of DCPN and 3 patients underwent the treatment of previous Meniere's disease.
CONCLUSION
The patients with DCPN were due to canalithiasis and cupulolithiasis of the lateral semicircular canal, and physical therapy for lateral semicircular canal was rewarding.