Dynamic visual acuity in benign paroxysmal positional vertigo

Abstract

Background: Head motions cause transient vertigo in patients with benign paroxysmal positional vertigo (BPPV) and may reduce visual ability.

Objectives: The aim is to investigate the clinical utility of dynamic visual acuity (DVA) test in those patients.

Material and methods: Thirty patients, 11 with lateral canal BPPV (6 geotropic and 5 ageotropic), and 19 with posterior canal BPPV, were evaluated with DVA test during rapid horizontal (left and right) and vertical (up and down) head movements. Patients were asked to identify the direction of the letter C, ranging from 1.0 to 0.0 logMAR, while moving their heads. The orientation of the optotype was randomly changed by a computer-generated program. Ten subjects were served as control. Data were analyzed with a one-way ANOVA. p Value <.01 was considered significant.

Results: Patients with LC and PC BPPV had significant DVA loss as compared with control subjects (p?<?.01). However, no significant difference was found in vDVA between patients with LC and PC BPPV, or in hDVA between ipsilesional and contralesional head rotation in patients with LC or PC BPPV (LC: p?=?.755, PC: p?=?.765).

Conclusions: Patients with BPPV may have impaired visual acuity, particularly during acute onset condition. Present study indicated that DVA test was not helpful for differentiation of the pathologic and normal ears.     

Patient,disease, and outcome characteristics of benign paroxysmal positional vertigo with and without Meniere’s disease

Abstract

Background: Meniere’s disease (MD)-associated benign paroxysmal positional vertigo (BPPV) is complex and difficult to diagnose, and reports of its prevalence, pathologic features and outcomes are sparse and conflicting.

Objective: Report disease characteristics and outcomes associated with the presence of MD in patients with BPPV.

Materials/methods: A retrospective study of patients with BPPV between 2007 and 2017 at a single, high-volume institution.

Results: Of 1581 patients with BPPV identified, 7.1% had MD and 71.9% of those patients had BPPV in the same ear(s) as MD. Patients with MD were more likely to have lateral semicircular canalithiasis (11.6% vs. 5.5%, p?=?.009) and multiple canalithiasis (7.1% vs. 2.5%, p?=?.005). MD was associated with an increased rate of resolution of BPPV (p?=?.008) but also increased time to resolution (p?=?.007). There was no association between MD and recurrence of BPPV.

Conclusions: MD is associated with lateral canalithiasis. Contrary to prior reports, BPPV in MD can affect either ear and was not associated with poorer outcomes than idiopathic BPPV.

Significance: The largest series to date investigating disease and outcome characteristics for BPPV in MD is presented. These data inform diagnosis and expectations in the management of these complex patients.     

Clinical characteristics and treatment outcomes for benign paroxysmal positional vertigo comorbid with hypertension

Conclusions: Patients with BPPV comorbid with hypertension (h-BPPV) tend to receive a delayed diagnosis of BPPV. Comorbidity with hypertension did not influence the efficacy of the repositioning maneuver; however, comorbidity with hypertension was associated with an increased recurrence rate of BPPV.

Objectives: To determine the clinical characteristics and outcomes of h-BPPV, as well as the clinical differences between h-BPPV and idiopathic BPPV (i-BPPV).

Methods: The authors reviewed the medical records of 41 consecutive patients with h-BPPV (the h-BPPV group) from March to December 2014 and 47 patients with i-BPPV (the i-BPPV group) during the same period.

Results: There were no significant differences in age, sex ratio, or the affected side between the h-BPPV and i-BPPV groups. The proportion of patients reporting an initial episode of positional vertigo was significantly lower in the h-BPPV group (51.22% vs 74.47%; p?=?.024). Patients in the h-BPPV group reported a longer median episode duration than did those in the i-BPPV group (60 days vs 15 days; p?=?.017). The results of treatment using repositioning maneuvers were similar between the two groups. At follow-up, 13 patients in the h-BPPV group were diagnosed with recurrent BPPV compared with six in the i-BPPV group (p?=?.031).     

Evaluation of bone mineral density and 25-(OH) vitamin D levels in middle-aged and elderly women with recurrent benign paroxysmal positional vertigo

Abstract

Background: Middle-aged and elderly perimenopausal women are prone to developing BPPV without definite cause. Objectives: This study aimed to investigate the correlation between bone mineral density (BMD), 25-(OH) vitamin D, and serum calcium levels in patients with benign paroxysmal positional vertigo (BPPV) in middle-aged and elderly women.

Material and methods: A total of 103 women with two or more recurrent BPPV episodes (group A) and 80 age-matched healthy controls (group B) were recruited. All subjects had BMD and serum 25-(OH) D levels measurements taken, and the results were compared.

Results: BMD was reduced in group A, and the proportion of osteoporosis was higher than in group B (p?=?.039). The BMD T-score and 25-(OH) vitamin D level were lower in group A than in group B (p?=?.004 and p?<?.0001, respectively). In group A, the BMD T-score was lower (p?=?.017) and serum 25-(OH) vitamin D level was higher (p?<?.0001) in premenopausal women than in menopausal women.

Conclusions and Significance: Our study found that middle-aged and elderly women with recurrent BPPV, especially postmenopausal women, may present decreased BMD and serum vitamin D levels.     

Low 25-hydroxyvitamin D levels in postmenopausal female patients with benign paroxysmal positional vertigo

Objective: Several studies have reported the association of benign paroxysmal positional vertigo (BPPV) with vitamin D deficiency. This study aimed to evaluate serum 25-hydroxy vitamin D (25 (OH) D) levels in native Chinese postmenopausal women with de novo idiopathic BPPV and to investigate the possible relationship between the occurrence of BPPV and low 25 (OH) D levels.

Methods: This retrospective study comprised of 85 postmenopausal women with de novo idiopathic BPPV and 80 age-matched healthy controls. All subjects had bone mineral density (BMD) and serum 25 (OH) D levels measurements recorded, and the results were compared.

Results: The prevalence of reduced BMD (T score?p?=?.004). The mean serum 25 (OH) D levels were also significantly lower in female patients with BPPV than in healthy controls (19.1?±?5.2 vs. 22.5?±?5.8, p?p?=?.031).

Conclusion: Our study suggests that low 25 (OH) D may be a risk factor for BPPV in postmenopausal women.     

Monitoring of caloric response and outcome in patients with benign paroxysmal positional vertigo.

OBJECTIVE: To analyze the time course of caloric response in patients with Benign Paroxysmal Positional Vertigo (BPPV). PATIENTS: Seventy-four individuals with diagnosis of BPPV during Dix-Hallpike (DH) test. STUDY DESIGN: A prospective, longitudinal study. SETTING: A tertiary referral center. INTERVENTION: Patients were treated by particle repositioning maneuvers according to the affected canal, and the effectiveness was evaluated at 180 and 360 days. Bithermal caloric response was obtained by using 44 and 30 degrees C water irrigations at diagnosis, 6 months, and 1 year after. MAIN OUTCOME MEASURE: Canal paresis (CP) and response to DH after treatment. RESULTS: The effectiveness of the treatment for BPPV (absence of vertigo and positional nystagmus during DH) was 65.2% (45 of 69) after 1 year of follow-up. Twenty-five percent of (16 of 64) individuals with BPPV presented CP at diagnosis, 27% (12 of 44) at 6 months, and 16% (9 of 56) 1 year after. One year after, seven individuals with CP showed a normal caloric response, another seven demonstrated persistent CP, and one case developed a bilateral CP. The effectiveness of particle repositioning maneuvers was not significantly different between subjects with or without CP after 1 year of follow-up (odds ratio, 1.31 [95% confidence intervals, 0.35-4.89], p = 0.88). CONCLUSION: Canal paresis is not associated with a lower outcome to repositioning.     

Assessment of sensory organization testing in benign paroxysmal positional vertigo patients before and after repositioning manoeuvre

Introduction and objectiveBenign paroxysmal positioning vertigo is considered the most common disorder of the peripheral vestibular system. After successful physical manoeuvres for BPPV, a number of patients complain of non-positional sustained imbalance of variable duration called residual dizziness lasting for several days. The objective of this study was to compare the posturographic changes before and one week after successful repositioning manoeuvres in patients with idiopathic BPPV.Materials and methodsThis study was a case–control study, where the first group was composed of 20 patients with confirmed BPPV diagnosis regardless of the affected canal or pathology. Twenty age and gender matched normal subjects constituted the control group. The sensory organization test was performed before and one week after a repositioning manoeuvre in BPPV patients.ResultsAll 20 BPPV patients, except 6 who had no significant improvement of symptoms even after disappearance of classic vertigo and nystagmus, had substantial improvement in sensory scores after CRPs in the antero-posterior visual and vestibular scores and the medio-lateral visual and global scores. All antero-posterior and medio-lateral scores before and after CRPs, except for the AP preferential score, were considerably poorer in BPPV patients than healthy subjects. The 6 patients, who showed no improvement after CRPs, presented with a history of non-specific symptoms i.e., light-headedness or sense of floating.ConclusionsSensory organization test might have a role in the assessment of residual dizziness in patients with BPPV after CRPs.     

Benign paroxysmal positional vertigo: analysis of our population and role of caloric tests

Introduction and objectivesBenign paroxysmal positional vertigo (BPPV) is the most common cause of vertigo in those patients who seek medical care. Although videonystagmography seems the most indicated diagnostic test, we tried to decrease the requested caloric tests to optimise resources and reduce associated costs.MethodsWe developed a diagnostic-therapeutic algorithm for patients with suspected BPPV whose provocation tests are positive to evaluate the need for caloric testing. We analysed the results of its application on 98 patients who were referred to our Neuro-otology Unit over 15 months requesting videonystagmography and caloric tests.ResultsOnly 24% of the requested tests were performed. No significant difference was found in our recurrence rate compared with other series of Spanish patients.ConclusionsVideonystagmography and caloric tests are not strictly necessary in most patients with BPPV and they should be performed only in patients whose diagnosis is unclear.     

Comparison between objective and subjective benign paroxysmal positional vertigo: clinical features and outcomes

Conclusions: Objective benign paroxysmal positional vertigo (O-BPPV) and subjective BPPV (S-BPPV) have similar demographic and clinical features. Canalith repositioning manoeuvres (CRMs) can be an effective treatment for patients with S-BPPV, and a diagnosis of positional nystagmus is not essential for considering CRMs. This study supports the use of CRMs as the primary treatment for S-BPPV.

Objective: To examine differences in demographic and clinical features, as well as treatment outcomes, between O-BPPV and S-BPPV.

Methods: The medical records of 134 patients with BPPV were reviewed for demographic characteristics, past medical history, associated symptoms, response to CRMs, interval between symptom onset and the first medical visit, and recurrence rate. The O-BPPV group (n?=?101) comprised patients who experienced vertigo and accompanying autonomic symptoms, and showed typical nystagmus. The S-BPPV group (n?=?33) comprised patients who, when subjected to a provoking manoeuvre, showed all of the classic BPPV symptoms but did not show nystagmus. All patients had at least 3 years of follow-up.

Results: The demographics (age and sex ratio), past medical history, and associated symptoms were not significantly different between the two groups. Posterior semi-circular canal BPPV appeared more than twice as often as horizontal semi-circular canal BPPV in patients with S-BPPV. However, both canals were affected to a similar proportion in patients with O-BPPV, and the difference was marginally significant (p?=?0.073). Overall improvement was better in O-BPPV than in S-BPPV; however, there was no significant difference. The total numbers of manoeuvres for recovery and the interval between symptom onset and the first medical visit also did not show any significant inter-group differences. During a 3-year follow-up, the recurrence rate was 13.8% for O-BPPV and 21.2% for S-BPPV.     

The relationship between hearing loss and vestibular dysfunction in patients with sudden sensorineural hearing loss

Objective: To investigate the relationship between hearing loss and vestibular dysfunction in patients with sudden sensorineural hearing loss (SSHL).

Methods: Clinical data including the symptom of vertigo of 149 SSHL patients were investigated retrospectively. Pure tone audiometry, ocular vestibular-evoked myogenic potential (oVEMP) and cervical vestibular-evoked myogenic potential (cVEMP) evoked by air-conducted sound (ACS), and caloric test were employed for cochlear and vestibular function assessment. The relationship between hearing level and vestibular dysfunction was analyzed.

Results: The pure tone averages (PTAs) (mean?±?SD) of SSHL patients with and without vertigo were 88.81?±?21.74 dB HL and 72.49?±?21.88 dB HL (Z?=??4.411, p?=?0.000), respectively. The PTAs of SSHL patients with abnormal and normal caloric test were 84.71?±?22.54 dB HL and 70.41?±?24.07 dB HL (t?=??2.665, p?=?0.009), respectively. Conversely, vertigo and abnormal caloric results also happened more frequently in patients with profound hearing loss. However, no consistent tendency could be found among vestibular evoked myogenic potentials (VEMPs) responses or hearing loss.

Conclusions: SSHL patients with vertigo or abnormal caloric test displayed worse hearing loss; and vice versa, vertigo and abnormal caloric results happened more frequently in SSHL patients with profound hearing loss.     

Vestibular and cochlear nerve enhancement on MRI and its correlation with vestibulocochlear functional deficits in patients with Ramsay Hunt syndrome

ObjectiveThe correlation between enhancement of the vestibulocochlear nerves on gadolinium-enhanced magnetic resonance imaging (MRI) and vestibulocochlear functional deficits was examined in patients with Ramsay Hunt syndrome (RHS).MethodsNineteen patients with RHS who showed herpes zoster oticus, peripheral facial palsy, and vertigo were enrolled. Canal paresis (CP) in the caloric test, abnormal response to ocular and cervical vestibular myogenic potentials (oVEMP and cVEMP), and refractory sensorineural hearing loss were evaluated. MRI images perpendicular to the internal auditory canal were reconstructed to identify the superior (SVN) and inferior vestibular nerves (IVN) and the cochlear nerve (CV). The signal intensity increase (SIinc) of the four-nerve enhancement was calculated as an index.ResultsAmong RHS patients, 79%, 53%, 17% and 26% showed CP in the caloric test, abnormal responses to oVEMP and cVEMP, and refractory sensorineural hearing loss, respectively. SIinc rates of the SVN were significantly increased in RHS patients with CP in the caloric test, and with abnormal responses to oVEMP and cVEMP. SIinc rates of the SVN tended to increase in RHS patients with refractory sensorineural hearing loss (p = 0.052). SIinc rates of the IVN were significantly increased in RHS patients with abnormal responses to oVEMP and cVEMP, and refractory sensorineural hearing loss, but not in those with CP in the caloric test. SIinc rates of the CN were significantly increased in RHS patients with CP in the caloric test, abnormal response to oVEMP and refractory sensorineural hearing loss, but not in those with abnormal response to cVEMP.ConclusionIn patients with RHS, the origin of vertigo may be superior vestibular neuritis, which is affected by reactive varicella-zoster virus from the geniculate ganglion of the facial nerve through the faciovestibular anastomosis. The results also suggested that in some RHS patients, inferior vestibular neuritis contributes to the development of vertigo and that the origin of refractory sensorineural hearing loss is cochlear neuritis.     

Otolith dysfunction in recurrent benign paroxysmal positional vertigo after mild traumatic brain injury

Background: The pathogenesis of recurrence of traumatic benign paroxysmal positional vertigo (BPPV) is poorly understood by far.

Objectives: To evaluate the value of secondary otolith dysfunction using vestibular evoked myogenic potential (VEMP) test in the pathogenesis of recurrence of BPPV after mild traumatic brain injury (mTBI).

Material and methods: We reviewed 42 patients with BPPV after mTBI. According to recurrence, patients were divided into two groups. Both cervical VEMP (cVEMP) and ocular VEMP (oVEMP) tests were performed on all of them.

Results: We detected abnormal cVEMP responses in four (26.7%) patients in the recurrent BPPV group after mTBI and five (18.5%) patients in the non-recurrent BPPV group after mTBI, and there was no significant difference between both groups. We detected abnormal oVMEP responses in nine (60.0%) patients in the recurrent BPPV group after mTBI and six (22.2%) patients in the non-recurrent BPPV group after mTBI, and there was a significant difference between both groups.

Conclusions and significance: Our study shows that oVEMP abnormalities in recurrent BPPV group after mTBI are significantly higher than those in non-recurrent BPPV group after mTBI. Therefore, we can conclude that secondary utricular dysfunction may be a potential pathogenesis of recurrence of traumatic BPPV.     

The evaluation of anxiety and panic agarophobia scores in patients with benign paroxysmal positional vertigo on initial presentation and at the follow-up visit

Conclusion: Patients with BPPV experienced short but intense anxiety and/or panic disorder, especially at the initial visit, but most patients recovered without medication with successful treatment.

Objective: Recent studies have shown that people with dizziness report some psychological problems such as panic and agoraphobia and anxiety. The aim of this study was to evaluate anxiety and panic agorophobia levels in patients with benign paroxysmal positional vertigo on initial presentation and at the follow-up visit and compare the scores with the control group.

Methods: All the 32 patients in the study had a diagnosis of BPPV confirmed by their history, typical subjective symptom reports, and characteristic positional nystagmus during the Dix–Hallpike test and/or Roll test. The patients were instructed to complete the standard forms of Beck anxiety inventory and panic agoraphobia scale questionnaire before and at 7 and 14 days after the canalith repositioning treatment.

Results: The validity scores of panic agoraphobia were statistically significantly higher in patients with BPPV than in the control group in each period (p?p?相似文献   

Concomitant diseases and their effect on disease prognosis in Meniere’s disease: diabetes mellitus identified as a negative prognostic factor

Objective: To study comorbidities and their effect on the disease progression in Meniere’s disease (MD).

Methods: Retrospective study on 350 definite MD patients diagnosed according to AAO-HNS 1995 criteria using hospital records and postal questionnaire.

Results: The prevalence of migraine, hypothyroidism, allergies, coronary heart disease and autoimmune diseases was more common in MD patients than reported in the general population of Finland. Diabetes mellitus was associated with both more severe hearing impairment (p?=?.033) and more frequent vertigo (p?=?.028) in MD patients. The number of concomitant diseases was associated with more frequent vertigo (p?=?.021).

Conclusions: A patient’s concomitant diseases, especially diabetes, should be treated effectively because they might affect the progression of MD. Further studies on the effects of concomitant diseases on MD prognosis are needed.     

CASP9 genotype confers gentamicin susceptibility in intratympanic treatment of intractable vertigo caused by Ménière’s disease

Background: Ménière’s disease (MD) is a disorder of the inner ear, causing episodes of vertigo. Although surgery is reserved for intractable MD, intratympanic gentamicin (ITG) injection has become an alternative for controlling vertigo.

Aims/Objectives: To investigate the genetic basis of ITG efficacy.

Material and methods: We hypothesized that single nucleotide polymorphisms (SNPs) affect outcomes in patients with MD who receive ITG injections. Whole-exome sequencing was used to determine variations in coding regions.

Results: Multivariate analysis revealed two SNPs, rs1052571 in caspase 9 (CASP9; p?=?.017) and rs3745274 in cytochrome P450 2B6 (p?=?.053), which were associated with susceptibility to ITG injections. Only the C-allele in the rs1052571 SNP was significantly associated with susceptibility (p?=?.027; odds ratio: 5.95; 95% confidence interval: 1.26–28.57, by Fisher’s exact test).

Conclusions and significance: Our results elucidated the role of the rs1052571 SNP and provide a genetic perspective on gentamicin efficacy (susceptibility) in treating intractable MD.     

Effects of Semont maneuver on benign paroxysmal positional vertigo: a meta-analysis

Background: Benign paroxysmal positional vertigo (BPPV) is the most common type of peripheral vertigo. This study aimed to evaluate the effects of the Semont maneuver (SM) for BPPV treatment, compared with other methods.

Methods: Studies were selected in relevant databases under pre-defined criteria up to June 2015. The Cochrane evaluation system was used to assess the quality of the studies. Effect size was indicated as a risk-ratio (RR) with corresponding 95% confidential interval (CI). Statistical analysis was conducted under a randomized- or fixed-effects model. Sub-group analysis was performed.

Results: Ten studies were included in the meta-analysis. All of the studies presented a low attrition bias, but a high selection and reporting bias. SM had a much higher recovery rate (SM vs no treatment: RR?=?2.60, 95% CI?=?1.97–3.44, p?p?p?Conclusion: SM is as effective as EM and BDE for BPPV treatment.     

Clinical outcomes of otitis media with effusion following palatoplasty in patients with incomplete cleft palate

Background: Diagnosis and treatment strategies for CP with OME and the timing of ear tube insertion remain controversial.

Objectives: To analyze the clinical outcomes of otitis media with effusion in children with incomplete cleft palate after palatoplasty prospectively.

Methods: A total of 30 children (10 months–2 years old) with incomplete CP were enrolled in this study and received at least 6 months of follow-up evaluations after palatoplasty.

Results: The overall improvement rate of OME was as high as 26% in this group. Average air conduction hearing threshold was significantly better than that before surgery in the 8 patients with improved OME (p?<?.05). Among the 8 children with improved OME, 7 (87.5%) were found to have middle ear effusion that improved within 6 months after CP repair. There was no significant difference in the improvement rate between the severe degree II group and the mild group.

Conclusion: A 6-month follow-up period is recommended. The severity of incomplete CP is not fully related to the function of the eustachian tube.

Significance: The overall improvement rate was as high as 26%, and effusion in the tympanic cavity subsided in 7 out of 8 cases within 6 months after the CP repair.     

Clinical and economic evaluation of minimally invasive cartilaginous palisade myringoplasty

Objectives: To test the clinical and audiometric efficacy of a minimally invasive myringoplasty technique, combining cartilaginous palisades while avoiding flap elevation, for small and wide perforations.

Methods: Over 4 years, this retrospective study included all patients over 6 years of age presenting an indication for myringoplasty. Several clinical and economic criteria were noted at 7 d, 2 months, 6 months and 2 years postoperative. The main outcome was the absence of perforation 2 years postoperative. The secondary outcomes were an audiometric gain at 6 months and the evaluation of the treatment cost.

Results: Thirty patients underwent the minimally invasive technique and 28 patients the technique with an elevation of the tympanomeatal flap. The minimally invasive surgical procedure was shorter (p?=?.001). At 2 years, the tympanic closure rate was equivalent (95% versus 89.5%, p?=?.77). The audiometric gain was similar between the two techniques (p?=?.09). From a medico-economic point of view, the minimally invasive procedure was the most effective because it was three times less expensive than the conventional technique with no reduction in efficacy (p?=?.02).

Conclusion: This quick and easy technique could be developed in an ambulatory setting or even in conditions adapted to consultation.     

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。     

Relationship between vertebral artery blood flow in different head positions and vertigo

Objective: To identify the vertebral artery blood flow in different head positions in patients with positional vertigo with no specific diagnosis.

Methods: Patients with history of vestibular symptoms associated with changes in head position were enrolled into the study. Healthy volunteers were evaluated as control group. Doppler ultrasonography examination of the cervical segment of the vertebral arteries was performed under three different head positions: (i) supine position, (ii) head hyperextended and rotated to the right side and (iii) head hyperextended and rotated to the left side.

Results: In the study group, right and left vertebral artery blood flow was significantly lower in the ipsilateral hyperextended position compared to standard supine position (respectively p?=?.014; p?=?.001), but did not differ significantly when compared between the standard supine and contralateral hyperextended positions (respectively?=?.959; p?=?.669). In the control group, left and right vertebral artery blood flow did not differ significantly when the head was hyperextended to the right or left sides compared to standard supine position (p?>?.05).

Conclusions: Our data demonstrated that the etiology of vestibular complaints in patients with undiagnosed positional vertigo might be related to impairment in vertebral artery blood flow according to head positions.