Bruintjes, Tj.D.,* Companjen, J.,† van der Zaag-Loonen, H.J. * & van Benthem, P.P.G. * *Apeldoorn Dizziness Centre, Gelre Hospital, Apeldoorn, The Netherlands, and †Amphia Hospital, Breda, The Netherlands Accepted for publication 14 January 2014 Clin. Otolaryngol. 2014, 39, 39–44
Objective: To evaluate the long-term efficacy of the Epley manoeuvre as a therapeutic procedure for posterior canal benign paroxysmal positional vertigo. Design: Randomised, double-blind, sham-controlled trial. Setting: A multidisciplinary dizziness unit in a nonacademic Hospital. Participants: Forty-four patients with posterior canal benign paroxysmal positional vertigo (BPPV) with a duration of at least 1 month. Participants were randomised in two groups of 22 and treated with either the Epley manoeuvre or a sham manoeuvre and followed up for 1 year after treatment. Main outcome measures: Conversion of a ‘positive’ Dix– Hallpike test to a ‘negative’ Dix–Hallpike test, impairments perceived by the dizziness assessed by the Dizziness Handicap Inventory (DHI).
Statistical analysis: Absolute and relative risks were computed, and Fisher’s exact test was used to compare the treatments. Results: Six patients were lost to follow up (five in the sham group, one in the Epley group). The Epley procedure resulted in a treatment success in 20/22 patients (91%) after 12 months of follow-up, whereas the sham procedure had a positive effect in 10/22 patients (46%; P = 0.001). The DHI was significantly lower in the Epley group at all follow-up assessments (median scores 12 months 0 (0–51) versus 20 (0–76), P = 0.003). Conclusion: The Epley manoeuvre provides long-term resolution of symptoms in patients with posterior canal BPPV.
Benign paroxysmal positional vertigo (BPPV) is the most common peripheral vestibular disorder. The incidence is estimated to be 64 cases per 100 000 population per year, the lifetime prevalence 2.4%.1,2 It is characterised by short-standing episodes of vertigo precipitated by a change in head position, the most common provoking movements being looking upwards, bending over and rolling over in bed. It is believed that dislodged otolithic debris inside one of the semicircular canals causes continuing movement of the endolymph, even after head movement has ceased.3 This results in bending of the cupula, thus provoking vertigo. In a vast majority of cases, the posterior semicircular canal is affected. The Dix–Hallpike manoeuvre confirms the diagnosis of posterior canal BPPV by eliciting vertigo as well as a typical nystagmus in the head-hanging position.
The most commonly utilised single treatment approach to posterior canal BPPV is the Epley manoeuvre. This manoeuvre involves a series of movements of the head and body in order to move the free-floating debris out of the posterior semicircular canal into the vestibule.4 In the latest update of the Cochrane review on the effectiveness of the Epley manoeuvre, it is concluded that there is evidence that the Epley manoeuvre is a safe, effective treatment for posterior canal BPPV in the short term, but that there is insufficient evidence that the manoeuvre provides a long-term resolution of symptoms.5 The present study examines the long-term efficacy of the Epley manoeuvre in the treatment of posterior canal BPPV by comparing the difference in outcome between the Epley manoeuvre and a sham manoeuvre. Patients and methods
Correspondence: Tj.D. Bruintjes, Apeldoorn Dizziness Centre, Gelre Hospital, P.O. Box 9014, 7300 DS, Apeldoorn, The Netherlands. Tel.: +31 55 5818181; Fax: +31 55 5818194; e-mail: [email protected] © 2014 John Wiley & Sons Ltd Clinical Otolaryngology 39, 39–44
Patients were recruited from the multidisciplinary dizziness clinic in Gelre Hospital in Apeldoorn. Those with an age over 18 years and a history of brief, position-related vertigo of at 39
ORIGINAL ARTICLE
A randomised sham-controlled trial to assess the long-term effect of the Epley manoeuvre for treatment of posterior canal benign paroxysmal positional vertigo
40
Tj.D. Bruintjes et al.
least 1 month were eligible for inclusion. An absolute requirement for inclusion in the study was a classic positive response to the Dix–Hallpike manoeuvre. This was defined as vertigo and upbeating and rotatory nystagmus beating towards the undermost ear in the head-hanging position on either the left or right side. In case of a bilateral positive DH manoeuvre, the side with the strongest nystagmus was seen as the affected side. Exclusion criteria were previous treatment with an Epley manoeuvre, cervical disc herniation and severe communication problems. The study was approved by the Medical Ethical Committee of the University Medical Center Utrecht. Informed consent, randomisation
The senior investigators (T.B. and P.P.v.B.) obtained informed consent from each patient before baseline study assessment. After inclusion, the patients completed the Dutch version of the Dizziness Handicap Inventory (DHI). Then, they were randomly assigned with a 1 : 1 ratio to one of two treatment groups. Numbered, sealed envelopes containing the treatment group assignment were prepared before the start of study. With the use of a computer program, one of the investigators (J.C.) randomly assigned the numbers to either the Epley or the sham group. A technician (S.M. or P.O.) opened the next numbered envelope. Patients and outcome assessors were blind to allocation. Procedure
Those patients randomised to the Epley group were treated by an experienced technician (S.M. or P.O.) with an Epley manoeuvre. The Epley manoeuvre was performed as initially described by Epley, but none of the patients received premedication before treatment, nor did we use a mastoid vibrator.4 The sham procedure was also performed by one of the technicians. It was similar to the Semont diagnostic manoeuvre: the patient was seated with the head turned 45° towards the unaffected ear; then, the patient was slowly tilted towards the affected ear (so that the patient lies on his side with the nose pointed upwards). Finally, the patient was slowly moved to the seated position again. After each Epley or sham manoeuvre, the Dix–Hallpike test was repeated. If necessary, a therapeutic manoeuvre (Epley as well as sham manoeuvre) was repeated up to two times. After the therapeutic procedure, patients were advised to sleep propped up for 48 h and to avoid lying down on the affected side for 48 h in order to prevent repositioned particles from returning to the posterior canal. Follow-up assessments were performed by a different technician from the one who performed the treatment, so
that the assessor was blinded to which manoeuvre the patient had received. In each patient, the technician performed a Dix–Hallpike manoeuvre. Follow-up visits were planned at one, three, six and 12 months after the initial treatment. At each visit, the patient was asked to fill out the Dutch version of the DHI.6 The DHI is a questionnaire which objectively quantifies the symptoms of dizziness. Its score ranges from 0 to 100 (higher scores imply more dizziness-related impairment). Outcome and statistical analysis
The primary outcome was the proportion of patients with a negative Dix–Hallpike test at 12-month follow-up. Secondary outcomes were the Dix–Hallpike test results at the other follow-up moments, the DHI score and the occurrence of adverse events. Randomisation was checked on baseline characteristics. Differences between the groups at each follow-up assessment were tested with regard to the proportion of patients with a negative Dix–Hallpike test and median DHI score. Continuous variables were tested with the Student’s t-test (normally distributed) or the Mann–Whitney U-test (skewed distribution), and nominal variables were tested with Fisher’s exact test. Apart from a complete case analysis, which uses only those patients who had complete follow-up assessments, we also used the last observation carried forward method (LOCF), in which the last result of the Dix–Hallpike test of a patient before dropping out was copied to all subsequent follow-up moments. If there was any imbalance between the groups at baseline (P < 0.10), the relation of these variables with the outcome after 12 months was assessed to identify potential confounders. Potential confounding was adjusted for by multivariate logistic regression. P values 600)
Excluded (n > 556), either not meeting inclusion criteria, or declined to participate
Randomized (n = 44)
Allocation Allocated to Epley manoeuvre (n = 22)
Allocated to sham manoeuvre (n = 22)
Follow-up Lost to follow-up (because of unrelated illness, n = 1)
Lost to follow-up (because of unrelated illness, n = 2, nausea/risk of falling, n = 2, unknown, n = 1)
Analysis Analysed (n = 21)
Analysed (n = 17)
Fig. 1. Flow diagram.
but patients in the sham group were slightly older than those in the Epley group (62.5 years versus 55.7 years, P = 0.08) (Table 1), and patients in the Epley group had a somewhat lower median DHI score than patients in the sham group (23, range 8–66 versus 33, range 16 72, P = 0.08). During the trial, six patients were lost to follow-up: one in the Epley group, five in the sham group. Reasons were unrelated illnesses (n = 3), nausea/risk of falling (n = 2) and unknown (n = 1). Patients who were lost to follow up more often had a positive Dix–Hallpike manoeuvre (4/6, 67%) than patients who stayed in the study (10/38, 26%, P = 0.07). Because of this selective dropout, multiple imputation, which is the preferred method for imputing missing values, was not applicable.8 We therefore chose to impute data with the last observation carried forward method. The Epley procedure resulted in a long-term treatment success of 20/22 (91%, 95% CI 71–99%), whereas the sham procedure had an effect in 10/22 (46%; 95% CI 24–68%, P = 0.003), leading to a relative risk of the Epley manoeuvre for treatment success of 2.0 (95%, CI 1.2–2.6) (Table 2). The DHI was significantly lower in the Epley group at all followup visits (Table 3). Although age and DHI were not balanced between the two treatment groups, both variables were not related to the treatment outcome at 12 months (P value for age: 0.17, P for © 2014 John Wiley & Sons Ltd Clinical Otolaryngology 39, 39–44
DHI: 0.86) and could therefore not confound the treatment effect. We did not find any adverse events or complications of treatment. More specifically, there was no conversion of posterior canal BPPV into horizontal canal BPPV. Discussion Synopsis of key findings and clinical applicability
This study shows that the Epley manoeuvre is not only an effective treatment for posterior canal BPPV in the short term, but also in the long term. After 12 months, symptoms had resolved in 91% of patients treated with the Epley manoeuvre compared with 46% of patients treated with the sham manoeuvre. The treatment results in the Epley group were relatively straightforward: 21 of 22 patients (95%) were BPPV free directly after treatment, and this result consisted during all follow-up visits. Of these 21 patients, one developed BPPV at the contralateral side and two had a recurrence which spontaneously resolved before the end of the follow-up period. One patient did not respond to treatment and remained BPPV positive at all visits. The results in the sham group were diverse: two patients withdrew from the study directly after randomisation,
42
Tj.D. Bruintjes et al.
Table 1. Patient characteristics Epley (n = 22)
Sham (n = 22)
P value
Mean age in years (SD) 55.7 (12.8) 62.5 (12.7) Males 10 (46%) 8 (36%) Presence of periodic 9 (41%) 9 (41%) dizziness 10 (0–300) 6 (0–660) Time since first appearance dizziness in months [median (min–max)] 2.3 (1–12) Mean duration of last 2.5 (0–24) episode in months (min–max) Post-traumatic BPPV 3 (14%) 1 (5%)
0.08* 0.76† 1.0† 0.99‡
0.85‡
0.61†
SD, standard deviation; BPPV, benign paroxysmal positional vertigo; DHI, Dizziness Handicap Inventory. *Compared with the Student’s t-test. † Compared with the Fisher’s exact test. ‡ Compared with the Mann–Whitney U-test.
leaving 20 patients in this group. Ten patients (50%) initially responded to the sham treatment of the affected side. Of these, four remained negative at all follow-up visits, two had a recurrence on the affected side which spontaneously resolved during follow-up, and three developed a recurrence
which did not spontaneously resolve. One had a recurrence which resolved, recurred again and had resolved at the final visit at 12 months. Ten patients initially did not respond to the applied sham manoeuvre; three remained positive at all follow-up visits, two remained positive and also developed BPPV at the contralateral side, and three were initially not responsive but the BPPV spontaneously resolved during follow-up. One had a spontaneous resolution after initially not responding, but at the final visit the BPPV had recurred, and in another one the initially unresponsive BPPV at the affected side had resolved, but BPPV had developed at the contralateral side. The difference in recurrence rate of BPPV in patients who underwent an Epley manoeuvre and a sham manoeuvre suggests that treatment of BPPV with the Epley manoeuvre lowers the risk of recurrence of BPPV. Comparison with other studies
Our results are in line with those from a pilot study (comparing the Epley manoeuvre with no treatment) that we published some years ago.7 Epley’s original study demonstrated a success rate of 97.7%.4 Although subsequent clinical trials reported somewhat lower success rates (Lynn 89%, von Brevern 80%), the overall picture is one of the very effective therapeutic procedures.9,10 A Cochrane systematic review included five randomised controlled trials of the Epley manoeuvre versus placebo (sham treatment) or no treat-
Table 2. Patients with negative Dix–Hallpike test result during follow-up Complete case analysis
1 month 3 months 6 months 12 months
Last observation carried forward
Epley
Sham
P*
RR (95% CI)
Epley (n = 22)
Sham (n = 22)
P*
RR (95% CI)
20/21 (95%) 19/21 (91%) 18/20 (90%) 20/21 (95%)
9/20 (45%) 9/18 (50%) 8/17 (47%) 9/17 (53%)
Objective: To evaluate the long-term efficacy of the Epley manoeuvre as a therapeutic procedure for posterior canal benign paroxysmal positional vertigo. Design: Randomised, double-blind, sham-controlled trial. Setting: A multidisciplinary dizziness unit in a nonacademic Hospital. Participants: Forty-four patients with posterior canal benign paroxysmal positional vertigo (BPPV) with a duration of at least 1 month. Participants were randomised in two groups of 22 and treated with either the Epley manoeuvre or a sham manoeuvre and followed up for 1 year after treatment. Main outcome measures: Conversion of a ‘positive’ Dix– Hallpike test to a ‘negative’ Dix–Hallpike test, impairments perceived by the dizziness assessed by the Dizziness Handicap Inventory (DHI).
Statistical analysis: Absolute and relative risks were computed, and Fisher’s exact test was used to compare the treatments. Results: Six patients were lost to follow up (five in the sham group, one in the Epley group). The Epley procedure resulted in a treatment success in 20/22 patients (91%) after 12 months of follow-up, whereas the sham procedure had a positive effect in 10/22 patients (46%; P = 0.001). The DHI was significantly lower in the Epley group at all follow-up assessments (median scores 12 months 0 (0–51) versus 20 (0–76), P = 0.003). Conclusion: The Epley manoeuvre provides long-term resolution of symptoms in patients with posterior canal BPPV.
Benign paroxysmal positional vertigo (BPPV) is the most common peripheral vestibular disorder. The incidence is estimated to be 64 cases per 100 000 population per year, the lifetime prevalence 2.4%.1,2 It is characterised by short-standing episodes of vertigo precipitated by a change in head position, the most common provoking movements being looking upwards, bending over and rolling over in bed. It is believed that dislodged otolithic debris inside one of the semicircular canals causes continuing movement of the endolymph, even after head movement has ceased.3 This results in bending of the cupula, thus provoking vertigo. In a vast majority of cases, the posterior semicircular canal is affected. The Dix–Hallpike manoeuvre confirms the diagnosis of posterior canal BPPV by eliciting vertigo as well as a typical nystagmus in the head-hanging position.
The most commonly utilised single treatment approach to posterior canal BPPV is the Epley manoeuvre. This manoeuvre involves a series of movements of the head and body in order to move the free-floating debris out of the posterior semicircular canal into the vestibule.4 In the latest update of the Cochrane review on the effectiveness of the Epley manoeuvre, it is concluded that there is evidence that the Epley manoeuvre is a safe, effective treatment for posterior canal BPPV in the short term, but that there is insufficient evidence that the manoeuvre provides a long-term resolution of symptoms.5 The present study examines the long-term efficacy of the Epley manoeuvre in the treatment of posterior canal BPPV by comparing the difference in outcome between the Epley manoeuvre and a sham manoeuvre. Patients and methods
Correspondence: Tj.D. Bruintjes, Apeldoorn Dizziness Centre, Gelre Hospital, P.O. Box 9014, 7300 DS, Apeldoorn, The Netherlands. Tel.: +31 55 5818181; Fax: +31 55 5818194; e-mail: [email protected] © 2014 John Wiley & Sons Ltd Clinical Otolaryngology 39, 39–44
Patients were recruited from the multidisciplinary dizziness clinic in Gelre Hospital in Apeldoorn. Those with an age over 18 years and a history of brief, position-related vertigo of at 39
ORIGINAL ARTICLE
A randomised sham-controlled trial to assess the long-term effect of the Epley manoeuvre for treatment of posterior canal benign paroxysmal positional vertigo
40
Tj.D. Bruintjes et al.
least 1 month were eligible for inclusion. An absolute requirement for inclusion in the study was a classic positive response to the Dix–Hallpike manoeuvre. This was defined as vertigo and upbeating and rotatory nystagmus beating towards the undermost ear in the head-hanging position on either the left or right side. In case of a bilateral positive DH manoeuvre, the side with the strongest nystagmus was seen as the affected side. Exclusion criteria were previous treatment with an Epley manoeuvre, cervical disc herniation and severe communication problems. The study was approved by the Medical Ethical Committee of the University Medical Center Utrecht. Informed consent, randomisation
The senior investigators (T.B. and P.P.v.B.) obtained informed consent from each patient before baseline study assessment. After inclusion, the patients completed the Dutch version of the Dizziness Handicap Inventory (DHI). Then, they were randomly assigned with a 1 : 1 ratio to one of two treatment groups. Numbered, sealed envelopes containing the treatment group assignment were prepared before the start of study. With the use of a computer program, one of the investigators (J.C.) randomly assigned the numbers to either the Epley or the sham group. A technician (S.M. or P.O.) opened the next numbered envelope. Patients and outcome assessors were blind to allocation. Procedure
Those patients randomised to the Epley group were treated by an experienced technician (S.M. or P.O.) with an Epley manoeuvre. The Epley manoeuvre was performed as initially described by Epley, but none of the patients received premedication before treatment, nor did we use a mastoid vibrator.4 The sham procedure was also performed by one of the technicians. It was similar to the Semont diagnostic manoeuvre: the patient was seated with the head turned 45° towards the unaffected ear; then, the patient was slowly tilted towards the affected ear (so that the patient lies on his side with the nose pointed upwards). Finally, the patient was slowly moved to the seated position again. After each Epley or sham manoeuvre, the Dix–Hallpike test was repeated. If necessary, a therapeutic manoeuvre (Epley as well as sham manoeuvre) was repeated up to two times. After the therapeutic procedure, patients were advised to sleep propped up for 48 h and to avoid lying down on the affected side for 48 h in order to prevent repositioned particles from returning to the posterior canal. Follow-up assessments were performed by a different technician from the one who performed the treatment, so
that the assessor was blinded to which manoeuvre the patient had received. In each patient, the technician performed a Dix–Hallpike manoeuvre. Follow-up visits were planned at one, three, six and 12 months after the initial treatment. At each visit, the patient was asked to fill out the Dutch version of the DHI.6 The DHI is a questionnaire which objectively quantifies the symptoms of dizziness. Its score ranges from 0 to 100 (higher scores imply more dizziness-related impairment). Outcome and statistical analysis
The primary outcome was the proportion of patients with a negative Dix–Hallpike test at 12-month follow-up. Secondary outcomes were the Dix–Hallpike test results at the other follow-up moments, the DHI score and the occurrence of adverse events. Randomisation was checked on baseline characteristics. Differences between the groups at each follow-up assessment were tested with regard to the proportion of patients with a negative Dix–Hallpike test and median DHI score. Continuous variables were tested with the Student’s t-test (normally distributed) or the Mann–Whitney U-test (skewed distribution), and nominal variables were tested with Fisher’s exact test. Apart from a complete case analysis, which uses only those patients who had complete follow-up assessments, we also used the last observation carried forward method (LOCF), in which the last result of the Dix–Hallpike test of a patient before dropping out was copied to all subsequent follow-up moments. If there was any imbalance between the groups at baseline (P < 0.10), the relation of these variables with the outcome after 12 months was assessed to identify potential confounders. Potential confounding was adjusted for by multivariate logistic regression. P values 600)
Excluded (n > 556), either not meeting inclusion criteria, or declined to participate
Randomized (n = 44)
Allocation Allocated to Epley manoeuvre (n = 22)
Allocated to sham manoeuvre (n = 22)
Follow-up Lost to follow-up (because of unrelated illness, n = 1)
Lost to follow-up (because of unrelated illness, n = 2, nausea/risk of falling, n = 2, unknown, n = 1)
Analysis Analysed (n = 21)
Analysed (n = 17)
Fig. 1. Flow diagram.
but patients in the sham group were slightly older than those in the Epley group (62.5 years versus 55.7 years, P = 0.08) (Table 1), and patients in the Epley group had a somewhat lower median DHI score than patients in the sham group (23, range 8–66 versus 33, range 16 72, P = 0.08). During the trial, six patients were lost to follow-up: one in the Epley group, five in the sham group. Reasons were unrelated illnesses (n = 3), nausea/risk of falling (n = 2) and unknown (n = 1). Patients who were lost to follow up more often had a positive Dix–Hallpike manoeuvre (4/6, 67%) than patients who stayed in the study (10/38, 26%, P = 0.07). Because of this selective dropout, multiple imputation, which is the preferred method for imputing missing values, was not applicable.8 We therefore chose to impute data with the last observation carried forward method. The Epley procedure resulted in a long-term treatment success of 20/22 (91%, 95% CI 71–99%), whereas the sham procedure had an effect in 10/22 (46%; 95% CI 24–68%, P = 0.003), leading to a relative risk of the Epley manoeuvre for treatment success of 2.0 (95%, CI 1.2–2.6) (Table 2). The DHI was significantly lower in the Epley group at all followup visits (Table 3). Although age and DHI were not balanced between the two treatment groups, both variables were not related to the treatment outcome at 12 months (P value for age: 0.17, P for © 2014 John Wiley & Sons Ltd Clinical Otolaryngology 39, 39–44
DHI: 0.86) and could therefore not confound the treatment effect. We did not find any adverse events or complications of treatment. More specifically, there was no conversion of posterior canal BPPV into horizontal canal BPPV. Discussion Synopsis of key findings and clinical applicability
This study shows that the Epley manoeuvre is not only an effective treatment for posterior canal BPPV in the short term, but also in the long term. After 12 months, symptoms had resolved in 91% of patients treated with the Epley manoeuvre compared with 46% of patients treated with the sham manoeuvre. The treatment results in the Epley group were relatively straightforward: 21 of 22 patients (95%) were BPPV free directly after treatment, and this result consisted during all follow-up visits. Of these 21 patients, one developed BPPV at the contralateral side and two had a recurrence which spontaneously resolved before the end of the follow-up period. One patient did not respond to treatment and remained BPPV positive at all visits. The results in the sham group were diverse: two patients withdrew from the study directly after randomisation,
42
Tj.D. Bruintjes et al.
Table 1. Patient characteristics Epley (n = 22)
Sham (n = 22)
P value
Mean age in years (SD) 55.7 (12.8) 62.5 (12.7) Males 10 (46%) 8 (36%) Presence of periodic 9 (41%) 9 (41%) dizziness 10 (0–300) 6 (0–660) Time since first appearance dizziness in months [median (min–max)] 2.3 (1–12) Mean duration of last 2.5 (0–24) episode in months (min–max) Post-traumatic BPPV 3 (14%) 1 (5%)
0.08* 0.76† 1.0† 0.99‡
0.85‡
0.61†
SD, standard deviation; BPPV, benign paroxysmal positional vertigo; DHI, Dizziness Handicap Inventory. *Compared with the Student’s t-test. † Compared with the Fisher’s exact test. ‡ Compared with the Mann–Whitney U-test.
leaving 20 patients in this group. Ten patients (50%) initially responded to the sham treatment of the affected side. Of these, four remained negative at all follow-up visits, two had a recurrence on the affected side which spontaneously resolved during follow-up, and three developed a recurrence
which did not spontaneously resolve. One had a recurrence which resolved, recurred again and had resolved at the final visit at 12 months. Ten patients initially did not respond to the applied sham manoeuvre; three remained positive at all follow-up visits, two remained positive and also developed BPPV at the contralateral side, and three were initially not responsive but the BPPV spontaneously resolved during follow-up. One had a spontaneous resolution after initially not responding, but at the final visit the BPPV had recurred, and in another one the initially unresponsive BPPV at the affected side had resolved, but BPPV had developed at the contralateral side. The difference in recurrence rate of BPPV in patients who underwent an Epley manoeuvre and a sham manoeuvre suggests that treatment of BPPV with the Epley manoeuvre lowers the risk of recurrence of BPPV. Comparison with other studies
Our results are in line with those from a pilot study (comparing the Epley manoeuvre with no treatment) that we published some years ago.7 Epley’s original study demonstrated a success rate of 97.7%.4 Although subsequent clinical trials reported somewhat lower success rates (Lynn 89%, von Brevern 80%), the overall picture is one of the very effective therapeutic procedures.9,10 A Cochrane systematic review included five randomised controlled trials of the Epley manoeuvre versus placebo (sham treatment) or no treat-
Table 2. Patients with negative Dix–Hallpike test result during follow-up Complete case analysis
1 month 3 months 6 months 12 months
Last observation carried forward
Epley
Sham
P*
RR (95% CI)
Epley (n = 22)
Sham (n = 22)
P*
RR (95% CI)
20/21 (95%) 19/21 (91%) 18/20 (90%) 20/21 (95%)
9/20 (45%) 9/18 (50%) 8/17 (47%) 9/17 (53%)
