Lateralization of horizontal semicircular canal canalolithiasis and cupulopathy using bow and lean test and head-roll test

Abstract

Accurate lateralization is important to improve treatment outcomes in horizontal semicircular canal (HSCC) benign paroxysmal positional vertigo (BPPV). To determine the involved side in HSCC-BPPV, the intensity of nystagmus has been compared in a head-roll test (HRT) and the direction of nystagmus was evaluated in a bow and lean test (BLT). The aim of this study is to compare the results of a BLT with those of a HRT for lateralization of HSCC-canalolithiasis and cupulopathy (heavy cupula and light cupula), and evaluate treatment outcomes in patients with HSCC-canalolithiasis. We conducted retrospective case reviews in 66 patients with HSCC-canalolithiasis and 63 patients with HSCC-cupulopathy. The affected side was identified as the direction of bowing nystagmus on BLT in 55 % (36 of 66) of patients with canalolithiasis, which was concordant with the HRT result in 67 % (24 of 36) of cases (concordant group). Lateralization was determined by comparison of nystagmus intensity during HRT in 30 patients who did not show bowing or leaning nystagmus. The remission rate after the first treatment was 71 % (17 of 24) in the concordant group and 45 % (5 of 11) in the discordant group. Both bowing and leaning nystagmus were observed in all patients with cupulopathy, and the side of the null plane was identified as the affected side. In conclusion, bowing and/or leaning nystagmus were observed in only 55 % of patients with HSCC-canalolithiasis, and the first treatment based on the result of BLT alone was effective in only 45 % of the patients in whom the BLT and HRT were discordant, which may suggest that the usefulness of BLT in lateralizing the HSCC-canalolithiasis may be limited.

Positional Audiometry in Patients with Light Cupula: A Preliminary Study

“…To examine bowing and leaning nystagmus, the patients were subjected to bowing (90°) and leaning (45°) in a sitting position. The direction of bowing nystagmus corresponded to the affected side while that of leaning nystagmus was opposite to the affected side, which was consistent with previous observations [2,8,9,11].…”

“…The diagnostic criteria for light cupula were the presence of persistent geotropic DCPN, which lasted for more than 2 minutes in a supine head-roll test, and the presence of a null plane where nystagmus disappeared with slight head rotation either to the right or to left. Determination of the affected side was made based on identification of a null plane, i.e., the side of a null plane corresponds to the affected side [2,8,9].…”

Pseudo-spontaneous nystagmus in horizontal semicircular canal canalolithiasis

“…[ 8 ] Moreover, because not only PSN but also leaning or lying-down nystagmus is not observed in all patients with HSCC canalolithiasis, [ 10 , 21 , 22 ] comparative interpretation of the results of a supine roll test, bow and lean test, and PSN would be essential in determining the affected side in HSCC canalolithiasis. [ 10 , 11 ] In our study, a caloric test was performed in 12 patients with PSN, which revealed no canal paresis in all patients. The fact that only 39% (12 of 31) of patients with PSN took a caloric test may impose limitation on the validity of this study because caloric weakness might have been superimposed on HSCC BPPV causing spontaneous nystagmus, even though clinical tests including head impulse test revealed no signs suggesting unilateral vestibulopathy.…”

Treatment of benign paroxysmal positional vertigo. A clinical review

“…The pathologic ear can be identified by applying the Ewald's second law: the quick phases of the most intense nystagmus point to the affected side ( Pérez-Vázquez et al., 2017 , von Brevern et al., 2015 ); but, many times it is difficult to recognize the stronger nystagmus. The bow and lean manoeuvre ( Choung et al., 2006 , Kim et al., 2016 , Lee et al., 2010 ; von Brevern et al, 2015 ; Yetiser and Ince, 2015 ) may be very useful and, in case of cupulolithiasis, the pseudospontaneous nystagmus ( Asprella-Libonati, 2014 , Asprella-Libonati, 2008 , von Brevern et al., 2015 ) can also help to identify the pathologic side.…”