425158 souras and KorresOtolaryngology–Head and Neck Surgery © The Author(s) 2010

OTOXXX10.1177/0194599811425158Balat

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Original Research—Otology and Neurotology

Subjective Benign Paroxysmal Positional Vertigo Dimitrios G. Balatsouras, MD1, and Stavros G. Korres, MD2

No sponsorships or competing interests have been disclosed for this article.

Otolaryngology– Head and Neck Surgery 146(1) 98­–103 © American Academy of Otolaryngology—Head and Neck Surgery Foundation 2012 Reprints and permission: sagepub.com/journalsPermissions.nav DOI: 10.1177/0194599811425158 http://otojournal.org

Received June 8, 2011; revised September 9, 2011; accepted September 9, 2011.

Abstract Objective. To study the demographic, clinical, pathogenetic, and nystagmographic features and treatment outcomes of subjective benign paroxysmal positional vertigo (BPPV). Study Design. Prospective clinical trial. Setting. Tertiary referral center. Subjects and Methods. Sixty-three patients were studied (mean [SD] age 55.4 [9.4] years), 27 men and 36 women, who presented with a positive history for BPPV and Dix-Hallpike or supine roll tests positive for vertigo but negative for nystagmus. A comprehensive history was obtained, followed by clinical examination of the ears, nose, and throat and a complete audiologic and neurotologic examination, including videonystagmography. All patients were treated with the appropriate canalith repositioning procedure, depending on the type of provoking positioning test. A group of 204 patients with typical BPPV were used for comparison. Results. Forty-five patients with subjective BPPV were successfully treated. Eighteen patients, in most of whom vertigo of other causes was identified, did not respond to treatment. Comparison between patients with subjective and typical BPPV showed similar epidemiological and clinical features. Treatment failed in 13.5% of patients with subjective disease, after excluding patients with different causes of positional vertigo, as compared with 7.8% of patients with typical BPPV (odds ratio = 1.8; 95% confidence interval, 0.7-4.7; P = .32). Conclusion. Subjective BPPV is quite common, accounting for more than one-fourth of patients with typical BPPV and sharing common features with it, with the exception of nystagmus. No statistical difference in treatment outcomes between patients with subjective and typical BPPV was found, but study of a larger sample is needed. Keywords benign paroxysmal positional vertigo, central positional vertigo, nystagmus, canalith repositioning, Epley, barbecue maneuver

B

enign paroxysmal positional vertigo (BPPV) is the most common clinical entity encountered in a neurotology clinic.1 Patients with this disorder complain of episodic vertigo of brief duration, provoked by head movements and accompanied by a characteristic paroxysmal positional nystagmus. The nystagmus is typically torsional-vertical or horizontal, depending on the semicircular canal involved, and is characterized by findings such as latency, crescendo and decrescendo, transience, reversibility, and fatigability.2 Diagnosis in most cases may be easily obtained using the DixHallpike and the supine roll tests. Application of canalith repositioning procedures (CRPs) results in successful treatment of the disease in most patients.3 A problem occasionally encountered in clinical practice is the presence of a positive history of BPPV with a negative diagnostic maneuver for positional nystagmus. Absence of vertigo and paroxysmal nystagmus during the Dix-Hallpike or the supine roll test usually may be attributed to fatigue due to previous motility, remission of the disease, or a different etiology. However, several patients experience vertigo and accompanying autonomic symptoms, although nystagmus is missing. This type of the disease has been characterized as “subjective BPPV”4 and, although not rare, has not been extensively studied in the past. The aim of this study was to investigate a group of patients with subjective BPPV diagnosed and treated during the past 3 years.

Methods During 3 years, all consecutive patients with subjective BPPV diagnosed at the neurotology unit of our Department were 1

ENT Department, Tzanion General Hospital, Piraeus, Greece ENT Department, National University of Athens, Hippokration Hospital, Athens, Greece 2

Corresponding Author: Dimitrios G. Balatsouras, MD, 23 Achaion Str.—Agia Paraskevi, Athens, 15343, Greece Email: [email protected]

Balatsouras and Korres studied. Criteria of diagnosis were (1) history of repeated brief episodes of vertigo with changes in head position; (2) vertigo provoked by the Dix-Hallpike or the supine roll test; (3) absence of any detectable nystagmus by naked-eye examination, during and after the provoking maneuvers; (4) duration of the disease of at least 1 month, with no signs of recent improvement; and (5) absence of evidence for another vestibular disease. Patients with any clinical, laboratory, or imaging findings suggesting pathology of the central nervous system were excluded. Patients diagnosed with typical BPPV during the same period were used for comparison. Age, sex, and duration of symptoms were recorded. Risk factors, such as trauma or cochleovestibular disease, were used to define the disease as either secondary, when a risk factor occurred, or idiopathic, when no risk factor could be identified. The protocol of the study was reviewed and approved by the local institutional review board. All patients underwent a complete otolaryngologic, audiological, and neurotologic evaluation. The Dix-Hallpike maneuver, followed by the supine roll test, was performed. Patients with vertigo and absence of nystagmus were enrolled into the study, whereas patients with evident nystagmus and vertigo were treated as having typical BPPV. To evaluate the severity of the vertiginous symptoms, the following scale was used5: (1) slight vertigo in the provoking position without autonomous symptoms, (2) severe vertigo with nausea, and (3) severe vertigo with severe nausea, vomiting, or hypotension. All patients were asked to return the following morning, immediately after sleep and with minimal activity, to avoid the phenomenon of fatigue. Diagnostic maneuvers were repeated, and eye movements were recorded by videonystagmography (VNG), using a 4-canal ICS CHARTR Videonystagmograph (GN Otometrics, Taastrup, Denmark). Consequently, a full VNG battery was applied, using a standard test protocol of visual and vestibular stimulation, described elsewhere.6 In patients unsuitable for VNG, electronystagmography (ENG) was performed. The obtained nystagmographic data were compared with data from 78 randomly selected patients with typical BPPV who underwent testing under similar conditions. Finally, in selected cases, magnetic resonance imaging (MRI) of the brain was ordered to exclude any central etiology. Patients with positive Dix-Hallpike maneuver were treated by the modified Epley CRP, whereas patients with positive supine roll test were treated by the barbecue maneuver.7 This maneuver involves rolling the patient 360° away from the affected ear, from supine position to supine position, in a series of 90° steps, to effect particle repositioning out of the involved horizontal canal into the utricle. In case of failure or incomplete remission of symptoms, the same maneuver was repeated every 3 to 5 days, until a maximum of 3 repetitions. Assessment of the success of the treatment included both patients’ relief from vertigo and negative Dix-Hallpike or supine roll test for vertigo and nystagmus. We accepted that a positive diagnostic maneuver for BPPV, which elicited vertigo without nystagmus on initial evaluation, in conjunction with successful treatment result after performance of the appropriate CRP, provided sufficient evidence to categorize a patient

99 as suffering from true subjective BPPV. Involvement of the vertical (posterior or anterior) or horizontal canal was further determined according to the evoking (Dix-Hallpike or supine roll) maneuver. According to treatment results, all patients with a provisional diagnosis of subjective BPPV were finally divided into 2 groups: (1) patients with subjective vertical or horizontal canal BPPV and (2) patients with vertigo of other causes who did not respond to treatment. Although all treatment failures were included in the second group, occasional genuine subjective BPPV cases who did not respond to treatment might have been included in this category as well.

Statistical Analysis Continuous variables were expressed as mean (SD), and categorical variables were expressed as frequencies and percentages. The significance of any difference between groups was evaluated by the t test for independent samples. The χ2 test was used to evaluate any potential association between categorical variables, and the Fisher exact probability test was used in cases with small samples. Odds ratios with 95% confidence intervals were calculated for the estimation of treatment results.

Results Between 2008 and 2010, 204 patients received diagnoses of BPPV. Another 65 patients presented with subjective BPPV. Two remained symptom free on repeat post–24-hour examination, probably due to spontaneous remission of the disease, and were excluded from further study. The demographic and clinical features of the patients are shown in Table 1. Twenty-seven patients were men (mean [SD] age 58.4 [7.9] years; range, 35-74 years), and 36 were women (mean [SD] age 53.3 [9.9] years; range, 32-72 years). Mean time from onset of symptoms was 4.6 months (range, 1-36 months). Neurologic examination was normal in all patients, but to exclude a central disorder, some of them underwent brain MRI, which was normal. Histories revealed posttraumatic BPPV in 9 patients and chronic otitis media in 1 patient. In 56 patients (88.9%), vertigo was provoked unilaterally during the Dix-Hallpike test and in 5 patients (7.9%) bilaterally. Because of the absence of nystagmus, differential diagnosis between disease of the posterior and the rare type of anterior canal could not be obtained initially. In 2 patients (3.2%), vertigo was provoked during the supine roll test, implying involvement of the horizontal canal. In both patients, the right horizontal canal was involved, as evidenced by the more intense geotropic nystagmus.2 In most patients (88.9%), vertigo was intense with accompanying nausea (grade 2). Twenty-three of the subjects (36.5%) had hearing impairment disproportionate to their age, either bilateral (27.0%) or unilateral (9.5%). In Table 1, similar data of our patients with typical BPPV are presented, as well as the data from statistical comparison between the 2 groups. No statistical differences regarding any of the studied variables were found. We performed VNG in all patients, with the exception of 3 (4.7%) who were submitted to ENG. The results are shown in

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Otolaryngology–Head and Neck Surgery 146(1)

Table 1. Demographic and Clinical Features of Patients with Subjective and Typical Benign Paroxysmal Positional Vertigo (BPPV)

Gender, No.  Male  Female Age, y, mean (SD) Duration of disease, mo, mean (SD) Etiology, No.  Idiopathic  Secondary Side of involvement, No.  Right  Left  Bilateral Vertigo severity, No.  1  2  3 Hearing impairment, No.

Subjective BPPV (n = 63)

Typical BPPV (n = 204)

27 36 55.4 (9.4) 4.6 (6.0)

 84 120 53.4 (10.5) 3.7 (4.2)

53 10

160  44

33 25  5

117  72  15

 3 56  4 23

 22 163  19  62

P Value .92     .15 .19 .42     .08       .75       .57

Table 2. Videonystagmographic (VNG) Findings in Patients with Subjective and Typical Benign Paroxysmal Positional Vertigo (BPPV) Subjective BPPV (Initial Diagnosis) (n = 63) VNG Findings Spontaneous nystagmus, No. Canal paresis, No.  Bilateral  Unilateral   Diseased ear   Normal ear Directional preponderance, No.   Toward diseased ear   Toward normal ear Canal paresis and directional   preponderance, No. Central findings, No.

 

Confirmed Subjective BPPV (n = 45)

Other Causes (n = 18)

Typical BPPV (n = 78)

P Valuea

 2 11  3  8  6  2  5  2  3  2

2 9 5 4 3 1 3 1 2 1

 3 19  6 13 10  3 12  4  8  5

.38 .22         .8     .48

—

8

  1

.006

a

Statistical comparison was made between the group of initially diagnosed patients with subjective BPPV (n = 63) and the group of typical BPPV patients (n = 78).

Table 2 and are compared statistically with the results of the group of examined patients with typical BPPV. It was found that the nystagmographic findings were similar for the 2 groups, as previously reported,6 with the exception of central nystagmographic findings, which were quite common in patients with an initial diagnosis of subjective BPPV who did not respond to treatment. In 4 patients (6.3%) a mild spontaneous nystagmus of the peripheral type was found, without optic fixation, which remained in most positions of positional testing. No spontaneous nystagmus was observed with optic fixation. Three patients with spontaneous nystagmus also had canal paresis, and 1 patient had directional preponderance. Thirty-one patients (49.2%) had abnormal findings on the caloric tests. Twenty patients (31.7%) had canal paresis and 8 patients (12.7%) had directional preponderance. Three patients

(4.7%) had both canal paresis and directional preponderance, with weakness in the diseased ear and directional preponderance toward the normal ear. Both patients with positive supine roll test had canal paresis. Finally, several central VNG findings were found in 8 patients from the second group, including disorders of the saccadic accuracy, saccadic pursuit, gaze-evoked nystagmus, and impaired fixation suppression of the vestibuloocular reflex. Interestingly, eye movement recording during the DixHallpike test showed the presence of paroxysmal positional nystagmus in 21 patients (33.3%), which was not evident by naked eye on initial evaluation. All of them belonged to group 1, which responded favorably to treatment. The nystagmus had low intensity, and in some cases, the torsional component was missing. Fourteen patients had typical upbeating-torsional

Balatsouras and Korres

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Table 3. Treatment Results in Patients with Subjective and Typical Benign Paroxysmal Positional Vertigo (BPPV)

Subjective BPPV patients   Vertical canal BPPV   Unilateral   Bilateral   Horizontal canal BPPV   Other causes  Total Typical BPPV patients   Vertical canal BPPV   Unilateral   Bilateral   Horizontal canal BPPV  Total

Total No. (%)

Success of First Treatment, No. (%)

Success of Second to Third Treatments, No. (%)

Failures, No. (%)

38 (60.3) 5 (7.9) 2 (3.2) 18 (28.6) 63 (100.0)

30 (47.6) — 1 (1.6) — 31 (49.2)

8 (12.7) 5 (7.9) 1 (1.6) — 14 (22.2)

— — — 18 (28.6) 18 (28.6)

168 (82.3) 15 (7.4) 21 (10.3) 204 (100.0)

142 (69.6) — 14 (6.9) 156 (76.5)

12 (5.9) 14 (6.9) 6 (2.9) 32 (15.7)

14 (6.8) 1 (0.5) 1 (0.5) 16 (7.8)

nystagmus, indicative of posterior canal involvement,2 and 7 patients had either pure downbeating or mixed torsional downbeating nystagmus, indicative of anterior canal disease.8 All subjects of the latter group had brain MRI, which proved negative. The modified Epley CRP was performed in all patients with a Dix-Hallpike test positive for vertigo and proved successful in 45 (71.4%), after 1 (31 patients) or 2 to 3 (14 patients) treatment sessions (Table 3). In the 2 patients with a positive supine roll test, the barbecue maneuver was performed and proved successful in both. In the patients of the second group who did not respond to treatment, further diagnostic evaluation revealed (1) transient vertebrobasilar ischemia in 5 patients, (2) central positional vertigo in 2 patients, and (3) vestibular paroxysmia in 4 patients. Seven patients remained undiagnosed. Comparison of treatment success between patients initially diagnosed with subjective BPPV and patients with typical BPPV yielded an odds ratio of 4.7 (95% confidence interval [CI], 2.2-9.9; P < .0001), in favor of patients with typical BPPV. After excluding the 11 patients in whom other diagnoses were obtained, and supposing that the remaining 7 undiagnosed patients represented genuine subjective BPPV not responding to treatment, the odds ratio was decreased to 1.8 (95% CI, 0.7-4.7; P = .32). It appears, thus, that similar treatment results were obtained between the 2 groups because no statistically significant difference was found, but study of a larger sample is needed to obtain definite conclusions.

Discussion Subjective BPPV is a quite common clinical entity that has not been studied extensively but accounts for a significant number of patients with BPPV. The percentage of subjective BPPV in relation to total BPPV cases ranges from 11.5%9 to 48%,10 according to various reports. Weider et al10 treated a group of 44 patients with BPPV, performing the Epley procedure. Twenty-one patients had subjective BPPV, and almost half had at least a 1-year duration of the disease, presenting

the lower cure rate (55.6%). The total patients with subjective BPPV were less responsive to CRP (76% cure rate), and the authors concluded that the underlying disorder might be another disease, such as vestibular atelectasis. Norré9 found 11 (11.5%) patients with no observable nystagmus out of 95 patients with BPPV and labeled them as having atypical paroxysmal vertigo. However, 4 had positional nystagmus in electronystagmography testing. The author treated his patients with vestibular habituation training and had less success in the atypical cases. Tirelli et al,11 in the first study specific for subjective BPPV, found 43 patients fulfilling the criteria for this diagnosis, whereas 198 patients had objective BPPV. Treatment by CRP resulted in complete (60.5%) or partial (32.5%) recovery. Lack of nystagmus was attributed to a small quantity of otoconia, leading to triggering of vertigo but not of nystagmus. Finally, Haynes et al,4 who were the first to introduce the term subjective BPPV, diagnosed and treated a group of 35 patients with this disorder and compared it with a group of 127 patients with objective BPPV. Treatment with the Semont maneuver proved almost equally successful in both groups. The authors attributed the lack of nystagmus either to fatigued nystagmus from previous testing or to less noxious forms of cupulolithiasis or canalolithiasis. We found 63 patients with subjective BPPV and 204 patients with typical BPPV. Diagnosis of subjective BPPV was finally confirmed in 45 patients, whereas in 11, another diagnosis was obtained. It may be hypothesized that the 7 remaining undiagnosed patients had true BPPV that did not respond to treatment. Probably, the main reason for the reported poorer response to treatment in subjective BPPV9,10 is because of the inclusion of patients with different vestibular syndromes in this group. If we presume that all our 7 undiagnosed patients had subjective BPPV unresponsive to treatment, the failure rate would be 13.5% in this group of patients, as compared with 7.8% in our patients with typical BPPV. Although there is no statistically significant difference between treatment outcomes in the 2 groups, study of a larger sample is needed to establish any existing difference. Another

102 confounding factor is the absence of certainty that all 7 cases were indeed subjective BPPV. It should be noticed that we used stricter criteria than in previous studies. Initial evaluation involved naked-eye examination, but all patients with subjective BPPV were examined the next morning, to avoid the phenomenon of fatigue and to perform nystagmography. We excluded patients with disease duration of less than 1 month or recently improved to avoid random spontaneous resolution, which would jeopardize the validity of our results. Inclusion of these patients would increase the percentage of subjective BPPV in our material to approximately 37.8% initially and to 30.7% after treatment, extrapolating for the cases unresponsive to CRPs. The main issue arising in cases with subjective BPPV is the explanation of the absence of nystagmus in patients with positional vertigo during the provoking maneuver. In addition, differential diagnosis from different clinical entities should be made. Various explanations for the absence of nystagmus have been offered. Weider et al10 hypothesized that the absence of open-eye nystagmus may be owing to the development of ocular fixation. A more plausible explanation is the hypothesis of limited otoconia.4 It is known that loose otoliths are quite common in the lumens of all the semicircular canals, being most commonly found in the posterior canal, but their presence is asymptomatic. Clinical manifestation of vertigo depends on the density, volume, and number of the suspending particles, which may vary in different patients.12 Thus, semicircular canal involvement may be subclinical, and the patient may experience symptoms if a critical mass is surpassed. Initially, vertigo may be the only manifestation, but apparently, with the increase of loose otoconia, the full picture of BPPV may be evident. It should be noticed that there is significant intersubject variability in the intensity of vertigo and its correlation with nystagmus. This is evident during caloric irrigations, whereupon intense vertigo may be present, even in the absence of nystagmus, or inversely, intense nystagmus may be accompanied by minimal vertigo. Accordingly, the presence of a small quantity of loose otoconia is usually asymptomatic but may occasionally manifest as vertigo of varying intensity. Finally, a mild nystagmus may get unnoticed with the naked eye but may become evident on examination with Frenzel lenses or nystagmography.11 This occurred in about one-third of our patients, revealing mostly posterior canal involvement but in 7 cases anterior canal disease. It is interesting that anterior canal involvement in subjective BPPV was more common than in typical BPPV,13 and it may be concluded that this clinical entity is more frequent than previously thought. Differential diagnosis between subjective BPPV and other causes of positional vertigo should be performed. There is a long list of such disorders, either central or peripheral.14 The most significant central causes of positional vertigo include transient vertebrobasilar ischemia and central positional vertigo. We found 5 patients with transient vertebrobasilar ischemia who were treated conservatively and improved significantly. Several central positional vertigo syndromes have been described, characterized mainly by prolonged nystagmus, usually downbeating, vertigo, and vomiting.14,15 All our patients who did not respond to

Otolaryngology–Head and Neck Surgery 146(1) treatment were evaluated with MRI, and only 2 were found with central lesions. One patient had a cerebellar infarct and the second had arachnoid cysts of the posterior cranial fossa. Peripheral causes of positional vertigo may include perilymph fistulas, superior canal dehiscence syndrome, atypical Meniere disease, vestibular atelectasis,16 and positional vertigo with specific gravity differential between cupula and endolymph. In addition, vestibular paroxysmia attributed to neurovascular cross-compression may be implicated.17 Four of our patients unresponsive to CRPs were diagnosed as having vestibular paroxysmia and were administered carbamazepine, resulting in significant improvement.

Conclusion Subjective BPPV, defined as a positive history of BPPV with a positioning test positive for vertigo but negative for nystagmus, is a common occurrence, accounting for more than onefourth of patients with typical BPPV. Its demographic, clinical, pathogenetic, and nystagmographic features are similar to those of typical BPPV. Treatment is based on the application of the appropriate CRP, depending on the provoking positioning test. No statistical difference in treatment results between patients with subjective and typical BPPV was found, but study of a larger sample is needed. Author Contributions Dimitrios G. Balatsouras, conception and design, acquisition of data, drafting the article, final approval for publishing; Stavros G. Korres, conception and design, analysis and interpretation of data, revising the manuscript critically for important intellectual content, final approval for publishing.

Disclosures Competing interests: None. Sponsorships: None. Funding source: None.

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