A possible objective test to detect benign paroxysmal positional vertigo. The role of the caloric and video-head impulse tests in the diagnosis

Background:Benign paroxysmal positional vertigo(BPPV)is characterized by vertigo lasting from seconds to minutes,induced by head movements.Objectives:Our study aimed to investigate the clinical significance of the caloric vestibular and video head-impulse tests(vHIT)diagnosing the disorder.Methods:68 patients suffering from posterior canal BPPV(25 male,43 females,mean age±SD,54.5±13.2 years)and 56 patients with a normal functioning vestibular system as control were investigated.Bithermal caloric test and vHIT was performed during the same medical check-up.Canal paresis(CP%),gain(GA)and asymmetry(GA%)parameters were calculated.Results:The Dix-Hallpike manoeuvre was only positive in 4%of this population.The CP%parameter was only pathologic in two patients,and there was no significant difference between control and BPPV patients(p=0.76).The GA value was never under 0.8 in this population,but GA%was abnormal in 63.2%.A significant difference comparing the GA%values to the control group was seen(p=0.034).There was no correlation detected between the CP%and GA%values in BPPV.Regarding the GA%value,61%sensitivity and 76%specificity was seen.Conclusion:The Dix-Hallpike manoeuvre was not often positive in the non-acute phase of BPPV;therefore,objective testing is essential.The caloric test does not have clinical significance in BPPV,but vHIT can be helpful based on the GA%parameter。

Influence of Air Flow Rate on Functional Evaluation of Semicircular Canals

Objective To study the influence of unilateral air flow rate change on the result of caloric test.Materials and Methods The unilateral weakness(UW) index was calculated when the air flow rate was set at 6 L /min in both ears(called symmetric stimulation) and again when it was set at 6 L /min in left ear and 3 L /min in the right ear(called asymmetric stimulation).Each individual subject was tested with both symmetrical and asymmetrical stimulations.Paired t test was used to examine the differences between results from symmetrical and asymmetrical stimulations.Result UW index decreased in response to asymmetrical stimulation.Conclusion Unilaterally decreased air flow rate can produce indices suggesting ipsilateral UW,which can be misleading.

Significance of Vestibular Testing on Distinguishing the Nerve of Origin for Vestibular Schwannoma and Predicting the Preservation of Hearing

Background： Determining the nerve of origin for vestibular schwannoma （VS）, as a method for predicting hearing prognosis, has not been systematically considered. The vestibular test can be used to investigate the function of the superior vestibular nerve （SVN） and the inferior vestibular nerve （IVN）. This study aimed to preoperatively distinguish the nerve of origin for VS patients using the vestibular test, and determine if this correlated with hearing preservation. Methods： A total of 106 patients with unilateral VS were enrolled in this study prospectively. Each patient received a caloric test, vestibular-evoked myogenic potential （VEMP） test, and cochlear nerve function test （hearing） before the operation and 1 week, 3, and 6 months, postoperatively. All patients underwent surgical removal of the VS using the suboccipital approach. During the operation, the nerve of tumor origin （SVN or IVN） was identified by the surgeon. Tumor size was measured by preoperative magnetic resonance imaging. Results： The nerve of tumor origin could not be unequivocally identified in 38 patients （38/106, 35.80%）. These patients were not subsequently evaluated. In 26 patients （nine females, seventeen males）, tumors arose from the SVN and in 42 patients （18 females, 24 males）, tumors arose from the IVN. Comparing with tile nerve of origins （SVN and IVN） of tumors, the results of the caloric tests and VEMP tests were significantly different in tumors originating from the SVN and the IVN in our study. Hearing was preserved in 16 of 26 patients （61.54%） with SVN-originating tumors, whereas hearing was preserved in only seven of 42 patients （16.67%） with IVN-originating tumors. Conclusions： Our data suggest that caloric and VEMP tests might help to identify whether VS tumors originate from the SVN or IVN. These tests could also be used to evaluate the residual function of the nerves after surgery. Using this information, we might better predict the preservation of hearing for patients.

Characteristics of the Cochlear Symptoms and Functions in Meniere＇s Disease

Background：Meniere＇s disease is a unique,progressive disease of the inner ear.The complex manifestation presents diagnostic challenges.The cochlear symptoms often present before vertigo and tend to be ignored.This study aimed to analyze the characteristics of cochlear symptoms and functions associated with Meniere＇s disease to investigate the regularity of the development of this disorder.Methods：One-hundred fifteen patients who were diagnosed with definite unilateral Meniere＇s disease at the Hearing and Vestibular Clinic of the Department of Otorhinolaryngology of Beijing Tongren Hospital from August 2013 to November 2015 were recruited in this retrospective study.Initial symptoms,duration from initial symptoms to the diagnosis,hearing thresholds,audiogram patterns,and caloric test results were collected and analyzed for each patient.Data were analyzed using SPSS 13.0 statistical software by Spearman＇s correlation,Kruskal-Wallis H test,Chi-square test,and Fisher＇s exact test.Results：The average hearing threshold of these patients was 45.24 ± 18.40 dB HL.A majority of the patients （55.65%） were in Stage 3.The initial presentation of the disorder in 58 cases （50.43%） comprised only cochlear symptoms without vertigo.A weak,positive correlation was found between the degree of hearing loss and duration of the disease from initial symptoms to the diagnosis （rs =0.288,P =0.002）.Upward-sloping,inverted ＂V,＂ downward-sloping,and flat pattern were the main audiometric patterns observed with a distinctive distribution between stages （P 〈 0.001）.Based on the configurations of audiograms,the audiometric patterns had a weak correlation to the duration （rs =0.269,P =0.004）,and there was a tendency of duration to rising from upward-sloping,inverted ＂V＂,downward-sloping to flat pattern.（H =10.024,P =0.018）.Frequencies of tinnitus in 56 patients （64.4%） were at the lowest points of the audiograms,i.e.,the frequencies of the poorest hearing threshold.The patients at an advanced stage （Stage 3 [56] and Stage 4 [73]） exhibited a significantly higher abnormality of canal paresis than those at the earlier stages （Stage 1 [23] and Stage 2 [42]） （χ^2 =5.973,P=0.015）.Conclusions：Patients with definite Meniere＇s disease always have a moderate to severe sensorineural hearing loss before diagnosis.Cochlear symptoms are the most common initial presentation.With the progression of the duration,the hearing impairment becomes more severe and the distribution of the audiometric pattem is distinctive between stages.

Vestibular and cochlear dysfunction in aging:Two sides of the same coin?

Objective:Nonspecific complaints of hearing loss,vertigo,imbalance,and instability,without a defined etiology,are very prevalent in the elderly population,with a great impact on morbidity and mortality in this age group.The objectives of this study were to verify whether there is age-related vestibular dysfunction and to test the association of vestibular dysfunction with presbycusis in the elderly population.Methods:Original retrospective analytical cross-sectional study,carried out with 80 patients who underwent a videonystagmography and complete audiometric evaluation due to nonspecific vestibular complaints,without a specific vestibular disorder diagnosis.Patients were selected and divided into two distinct age groups(group A:>60 years;group B:18-50 years)and,in both groups,we analyzed the caloric tests and the pure-tone audiometry.Results:In the vestibular evaluation,we found that there was a statistically significant difference(P<0.05)between groups in the prevalence of bilateral vestibular weakness(group A:22.5%;group B:5%),and that the increase in age,above 60 years,is negatively correlated with the mean total caloric response.Additionally,we obtained a reasonable negative and statistically significant correlation(r=-0.320,P<0.05)between the mean bone conduction thresholds at high frequencies and total caloric responses in group A.Conclusions:In patients with hearing loss,it is essential to perform a complete vestibular study to diagnose vestibular disorders and,consequently,prevent adverse outcomes that may result from these alterations.