title: Benign paroxysmal positional vertigo with simultaneous involvement of multiple semicircular canals.
abstract: OBJECTIVE
  Benign paroxysmal positional vertigo (BPPV) generally involves a single semicircular canal (single canal BPPV) but it has been reported that more than one semicircular canal on either the same or the opposite side can be involved in 6.8-20% of the cases (multiple canal BPPV). In this study, the clinical characteristics of multiple canal BPPV were analyzed and compared to those of single canal BPPV.
  
  
  METHODS
  Retrospective analysis was performed on 1054 consecutive patients diagnosed with BPPV. Multiple canal BPPV was diagnosed when the combination of typical nystagmus was provoked by the Dix-Hallpike and supine head roll tests. Canalith repositioning maneuver was performed sequentially starting with the semicircular canal causing more severe nystagmus or symptoms. Clinical characteristics and the treatment course were statistically compared between single canal BPPV and multiple canal BPPV.
  
  
  RESULTS
  Among the 1054 patients, single canal BPPV was diagnosed in 1005 patients (95.4%) while multiple canal BPPV was diagnosed in 49 patients (4.6%). BPPV involving semicircular canals on the same side was more common (79.6%) than BPPV with bilateral involvement. The most common combination of the involved canals was ipsilateral posterior and horizontal semicircular canals (63.3%). Multiple canal BPPV was significantly more associated with underlying otologic diseases, especially labyrinthitis. Multiple canal BPPV required more treatment sessions and longer duration of treatment to achieve resolution of nystagmus and symptoms.
  
  
  CONCLUSIONS
  As all cases of multiple canal BPPV were treated successfully although a longer duration of treatment and more treatment sessions were required compared to single canal BPPV, the results of our study could aid in making an accurate diagnosis and providing appropriate treatment of multiple canal BPPV.
authors.affiliation: Department of Otorhinolaryngology, Myongji Hospital, Goyang, Korea.
authors.forename: Dae Bo
authors.initials: DB
authors.lastname: Shim
authors.affiliation: Department of Otorhinolaryngology, Myongji Hospital, Goyang, Korea.
authors.forename: Chang Eun
authors.initials: CE
authors.lastname: Song
authors.affiliation: Department of Otorhinolaryngology, Myongji Hospital, Goyang, Korea.
authors.forename: Eun Jung
authors.initials: EJ
authors.lastname: Jung
authors.affiliation: Department of Otorhinolaryngology, Myongji Hospital, Goyang, Korea.
authors.forename: Kyung Min
authors.initials: KM
authors.lastname: Ko
authors.affiliation: Department of Otorhinolaryngology, Myongji Hospital, Goyang, Korea.
authors.forename: Jin Woo
authors.initials: JW
authors.lastname: Park
authors.affiliation: Department of Otorhinolaryngology, Myongji Hospital, Goyang, Korea.
authors.forename: Mee Hyun
authors.initials: MH
authors.lastname: Song
keywords: Benign paroxysmal positional vertigo; Labyrinthitis; Multiple; Semicircular canal