Four cases of benign paroxysmal positional vertigo involving the putative shortarm-type posterior semicircular canal BPPV

Abstract

Benign paroxysmal positional vertigo (BPPV) is one of the most common causes of vertigo, and the posterior canal is the most frequently involved structure because of its anatomical position. In the majority of posterior canal BPPV cases, a particle-repositioning maneuver, such as the Epley maneuver, is effective, since the otoconia is thought to be located in the long arm of the posterior canal. However, Oas et al. has proposed a subtype of posterior canal BPPV, known as short-arm type BPPV, in which the otoconia is assumed to be located not in the long arm of the posterior canal, but in the short arm (between the utricle and the cupula). Here, we present four cases of BPPV that presumably involve the short-arm type posterior canal. The duration of nystagmus was extended in all four cases when the head was moved as in the Dix Halllpike test. Furthermore, when the head was moved back to a sitting position, the reversal of nystagmus was not or very faintly observed. As a treatment, the Epley maneuver was initially attempted, but this treatment was not effective. However, vibration methods (involving the application of vibration to the mastoid process of the affected ear with the intact ear positioned downwards) were effective in all four cases.

Diagnosis and treatment of the short-arm type posterior semicircular canal BPPV

“…It is essential to distinguish short-arm type BPPV and long-arm type BPPV because the path otoliths return to utricle is completely different and requires different therapy maneuvers. 8 , 9 , 10 In contrast, whether the otolith is floating in the semicircular canal or adhering to the cupula, the choice of therapy maneuver is nearly the same. However, there is currently a lack of systematic and in-depth research on how to distinguish between short-arm type BPPV and long-arm type BPPV.…”

“… 6 In 2011, Taura reported four cases of short-arm type PSC-BPPV and noted that the reversal of nystagmus was not or very faintly observed during sitting up from the Dix–Hallpike position. 9 Buki reported that the unilateral sitting up vertigo/body sway felt/shown by the patients during sitting up from the Dix–Hallpike position is more common in short-arm canalolithiasis than in long-arm canalolithiasis. 10 , 13 For therapy, repetitive sit-ups from the Dix–Hallpike positions, 10 application of vibration to the mastoid process of the affected ear with the healthy ear positioned downwards, 9 and positioning the head upside down 8 are recommended to return the otoconia from the short arm into the utricle.…”

“… 7 To move otoconia out of the short arm of the PSC, a substantially different process from moving them of the long arm, clinicians require different maneuvers. 8 , 9 , 10 The present study aims to redesign the diagnosis and treatment strategy of PSC-BPPV, not only to determine which semicircular canal is affected but also to determine whether the otoconia are in the short arm or the long arm. It is convenient to treat short-arm lithiasis with the bow-and-yaw maneuver ( Fig.…”