Natural course of positional down-beating nystagmus of peripheral origin

Abstract

The aim of this study was to assess the natural course of positional down-beating nystagmus (pDBN) and vertigo in patients with no evidence of central nervous system involvement and of presumed peripheral origin. Fifty-three patients with pDBN had a complete otoneurological examination. All subjects, apart from three (excluded from the study), showed no additional neurological signs and normal brain imaging. Patients were randomly assigned to two groups: with or without treatment with exercise. Patients were seen again after 24 h, and then weekly for up to 6 months. Forty-seven patients (94%) showed pDBN in the straight head-hanging position and in a Dix-Hallpike position. A torsional component was detected in 17 patients (34%). The mean latency and duration of pDBN was 4.7 ± 5 s and 40.1 ± 22 s, respectively. After 2 weeks, only 12 patients (24%) still had pDBN and all but one patient had recovered by 1 month. Twenty patients (40%) were diagnosed with a typical posterior canal benign paroxysmal positional vertigo (PC BPPV) before or after pDBN. This study assessed for the first time the natural course of presumed peripheral pDBN, which was characterized by a spontaneous remission in 24 patients in the first week and in 49 patients within 4 weeks. pDBN is much more common than previously suggested, with about the same frequency as lateral canal BPPV. Furthermore, the clinical characteristics of pDBN have been highlighted, as well as its possible relationship to PC BPPV.

Benign paroxysmal positional vertigo: Diagnostic criteria

“…Indeed, the posterior canal is by far the most frequently affected canal (80-90%); next is the horizontal canal (5-30%) [25,38,73]. Involvement of the anterior canal is rare, accounting for only 1% to 2% of patients in large case series [38,60,81] although some recent reports have suggested a considerably higher incidence [20,45]. Theo-retically, each of the three semicircular canals of the labyrinth can be affected by canalolithiasis or cupulolithiasis, resulting in six combinations (not counting multiple canal involvement) for each ear.…”

“…In the Dix-Hallpike position, nystagmus may be stronger or exclusively present with the affected ear up or down. The most sensitive diagnostic test for BPPV of the anterior canal seems to be the straight head-hanging position [20,22]. Thus, in canalolithiasis of the anterior canal, the direction of the torsional component, rather than the side of the Dix-Hallpike maneuver, indicates the affected side.…”

“…9. The latency between the completion of the diagnostic positional maneuver and the onset of positional nystagmus may be as long as 30 seconds in rare cases [20,57]. 10.…”

Benign Paroxysmal Positional Vertigo of Lateral Semicircular Canal: A Systematic Review and Meta-Analysis

“…Ten articles [17,[20][21][22][23][26][27][28][29][30] were retrieved by the electronic search. An additional article [24] was given from back references of the articles by Kim and colleagues [21,22].…”

“…The article by Cambi and colleagues [26] discussed positional downbeating nystagmus which, if not due to central causes, indicates superior semicircular canal BPPV and thus was considered irrelevant. The incidence of BPPV following the use of mallet osteotomes versus screwable osteotomes for closed sinus floor elevation was compared in a RCT [27].…”