Occurrence of semicircular canal involvement in benign paroxysmal positional vertigo

Objectives: To study the occurrence of each variant of benign paroxysmal positional vertigo (BPVV) and to present some specific clinical features and the results of their treatment by appropriate repositioning maneuvers. Study Design: A retrospective review of the records of patients with BPPV. Setting: Neurotology clinic of the ear, nose, and throat department of a general hospital. Patients: One hundred twenty-two patients were included in the study, 54 male and 68 female, mean ages 61.8 and 59.6 years, respectively, ranging in age from 25 years to 86 years and with symptoms lasting for an average of 124 days. The diagnosis of each type of BPPV was based on the history of the patients and on the positive results of the appropriate provoking maneuver. Methods: From all the patients, a comprehensive history was obtained, followed by clinical examination of the ears, nose, and throat and a complete audiologic and neurotologic examination, including electronystagmography. All patients were treated with an appropriate repositioning maneuver, depending on the type of BPPV. Results: Of 122 patients, 110 had posterior canal involvement, 10 had horizontal canal involvement, and only 2 had the anterior canal variant. The canalith repositioning procedure was immediately successful in 106 patients and in 8 more patients proved successful after its repetition in a second session, resulting in a total success rate of 93.4%. Conclusions: All the BPPV variants shared the same clinical and demographic characteristics and responded equally well to treatment. However, differential diagnosis was necessary to apply the appropriate canalith repositioning procedure. Although data from clinical and histologic studies do not fully account for the observed relative occurrence of each variant of BPPV, a satisfactory explanation may be provided by the anatomic location of each semicircular canal and additionally by self-treatment of most cases of the horizontal and the anterior canal variety.