Objective The purpose of the study was to evaluate the efficiency of the supine roll test(SRT)and alternative positional tests(APTs)including the bow and lean test(BLT),pseudo-spontaneous nystagmus(PSN),and lying down nystagmus(LDN)to identify the affected side in horizontal canal benign paroxysmal positional vertigo(HC-BPPV).Methods In our prospective study,we performed a testing profile(PSN,BLT,LDN,SRT)on 59 HC-BPPV patients using videonystagmography.We compared the accuracy and sensitivity of these tests in HC-BPPV lateralization.Data from 30 healthy patients were collected as the control group.Results When performing positional tests,the elicited nystagmus coinciding with Ewald’s second law was defined as a“positive response”.In 44 patients with geotropic nystagmus,the rates of positive response in LDN,PSN,and BLT were 22/44(50%),19/44(43%),and 18/44(41%),respectively,while in 15 patients with apogeotropic nystagmus,the positive response rates of these three tests were 10/15(66.7%),9/15(60%),and 4/15(27.00%),respectively.The sensitivity of LDN(54.38%)was higher than that of PSN(47.37%)and BLT(38.60%)but lower than that of SRT(89.47%).Notably,the accuracy rate of PSN(71.8%)was higher than that of the other APTs.In 6 patients with symmetrical nysgtamus during the roll test,5 patients showed a positive response in both LDN and BLT(83.34%),whereas 4 patients showed a positive response in PSN(66.67%).Conclusion All positional tests are helpful for determining the affected side of HC-BPPV,but SRT carries the highest accuracy of lateralization followed by PSN.
K^(+)cycling in the cochlea is critical to maintain hearing.Many sodium-potassium pumps are proved to participate in K^(+)cycling,such as Na/K-ATPase.Theα2-Na/K-ATPase is an important isoform of Na/K-ATPase.The expression ofα2-Na/K-ATPase in the cochlea is not clear.In this study,we used C57BL/6 mice as a model of presbycusis and implemented immunohistochemistry staining and quantitative real time-PCR,and theα2-Na/K-ATPase expression pattern was confirmed in the inner ear.It was foundα2-Na/K-ATPase was expressed widely in cochlea and its mRNA and protein expression was gradually reduced with aging(4-,14-,26-and 48-weeks old mice).We suspected that,the down-regulation ofα2-Na/K-ATPase expression might be associated with the remodeling of K^(+)cycling,degeneration of morphological structure and decrease of hearing function in aging C57 mice.In conclusion,we speculated that the reduction ofα2-Na/K-ATPase might play an important role in the pathogenesis of age-related hearing loss.
Yun LIUHan-qi CHUYan-bo SUNDan BINGLiang-qiang ZHOUJin CHENQing-guo CHENZhi-hui DU
