Canalith repositioning for benign paroxysmal positional vertigo: A randomized, controlled trial.
We assessed the efficacy of the canalith repositioning maneuver by comparing it with no treatment in a population of patients with benign paroxysmal positional vertigo (BPPV). In this randomized, controlled, 6-month efficacy trial, outcomes were measured subjectively by patients' reports of symptom status and objectively by Hallpike testing. During the first month of the study, the treated group experienced significantly better outcomes than did the control group, but this trend was not sustained at 3 and 6 months.
Benign paroxysmal positional vertigo (BPPV), first described in 1921,  is the most common type of vertigo of peripheral origin. The diagnosis is based on findings of typical positional rotatory nystagmus provoked by the head-hanging position (Hallpike maneuver)  and the observation of certain characteristic features, including a brief latency (usually 1 to 5 sec), limited duration (usually [greater than]30 sec), reversal on assuming an upright position, and a fatiguing of the response on repeat testing. In the head-hanging, left-ear-down position, the nystagmus occurs in a clockwise direction; in the head-hanging, right-ear-down position, the direction is counterclockwise. 
Symptoms of BPPV are triggered by head movement. Most occur when the patient gets in and out of bed, leans back, bends over, or looks up.
The pathophysiology of BPPV can be traced to a dysfunction of the posterior semicircular canal. Schuknecht found basophilic deposits on the cupulae of the posterior semicircular canal in patients with BPPV.  He developed a theory to explain the clinical classification of BPPV, which he called the cupulolithiasis theory. Schuknecht proposed that statoconia detach from the utricle when a patient moves the head into the critical position. Twenty-three years later, Parnes and McClure proposed the canalolithiasis theory, which was based on their observations of free-floating amorphous material in the posterior semicircular canal during semicircular canal occlusion surgery in patients with BPPV. 
Vestibular habituation exercises are an effective treatment for most patients with typical BPPV. Semont et al 'reported success rates of 84 and 93% after treatment with one and two liberatory maneuvers, respectively.  Epley reported 100% success in 30 patients with the canalith repositioning maneuver.  However, both of these studies were uncontrolled. One of the few truly controlled studies was reported by Herdman et al, who tested the effectiveness of both the liberatory and canalith repositioning maneuvers and found that they were equally effective.  In another controlled study, Blakley found no significant difference between a group that underwent the canalith repositioning maneuver and a control group that did not. 
Pharmacologic treatment with vestibular suppressants is generally ineffective.  Surgical interventions-singular neurectomy and posterior semicircular canal occlusion-are effective, but they are reserved for patients with intractable conditions who do not respond to conservative treatment. [11-15]
The objective of our study was to compare the efficacy of the canalith repositioning maneuver with no treatment over a period of 6 months.
Materials and methods
We identified all patients with the classic signs of BPPV who had come to the Neurotology Clinic at Chulalongkom University Hospital in Bangkok during the 24-month period between November 1996 and October 1998. All patients provided a thorough neurotologic history and underwent a physical examination. An absolute requirement for inclusion in this study was a positive nystagmus response to the Hallpike maneuver. Patients underwent a complete bedside vestibular test--including an oculomotor test, a positional and positioning test, a Romberg's test, and a tandem gait test--and most of them underwent audiography and electronystagmography.
After a diagnosis of BPPV was confirmed in 85 patients, they were randomly assigned to either the treatment (n = 42) or control (n = 43) group. Multivariate analysis revealed that there were no statistically significant differences between the two groups with respect to age, sex, duration of symptoms, affected side, and the results of audiologic testing and electronystagmography (table 1).
All patients in the treatment group underwent the canalith repositioning maneuver described by Epley, with the exception of the vibration component.  All were informed of the procedure's after-effects, including a feeling of dizziness or instability.
During the maneuver, the patient sat on a horizontal examining table. The physician guided the patient backward into the provocative position (the Hallpike maneuver) with the diseased ear down. Assuming this position provoked the vertigo and torsional nystagmus typical of BPPV. The patient remained in this position for 1 to 2 minutes until the nystagmus disappeared. The patient's head was then rotated 45[degrees] toward the contralateral side while it remained hanging over the edge of the examining table. Then the head and body were rotated 135[degrees] until the patient was facing down while lying in the supine position. The patient remained in this position for 1 to 2 minutes and then returned to the sitting position. The patient was then cautioned about the possibility of the onset of dizziness and was advised to keep the head relatively upright for 48 hours, even during sleep.
No antivertiginous drugs were prescribed for either group, but all patients were instructed to take vitamin [B.sub.1,6,12] three times a day. Patients were assessed at 1 week, 2 weeks, 1 month, 3 months, and 6 months.
During followup visits, patients were evaluated subjectively by self-reports of symptom status and objectively by their response to the Hallpike maneuver. They were also asked if they experienced any after-effects of therapy. We used three categories to classify subjective responses to treatment: (1) complete resolution, (2) improvement, and (3) no improvement or worsening. The results of the Hallpike test were classified as either positive or negative.
Followup at 1 and 2 weeks. Of the original 85 patients, 74 (35 treated patients and 39 controls) returned for followup at both week 1 and week 2 (table 2). In the treatment group, improvements in symptom status were reported by 31 patients (88.6%) at both followup visits. In the control group, favorable symptom status was reported by 22 patients (56.4%) at week 1 and by 24 patients (61.5%) at week 2. There were statistically significant differences between the two groups at both week 1 (p=0.001) and week 2 (p=0.021).
With respect to responses to the Hallpike maneuver, there was no significant difference between the groups at week 1, but the treated patients did have a significantly higher proportion of negative responses at week 2 (table 2.)
Followup at 1 month. At 1 month, favorable symptom status was reported by 32 of 34 treated patients (94.1%) and by 28 of 36 controls (77.8%) (table 3). Negative findings on the Hallpike test were seen in 31 patients (91.2%) and 23 controls (63.9%). There were statistically significant differences between the two groups in both subjective (p=0.045) and objective (p=0.0065) measures.
Followup at 3 and 6 months. At 3 months, favorable symptom-status outcomes were seen in 26 of 28 treated patients (92.9%) and 22 of 25 controls (88%)--not a statistically significant difference (table 4). Likewise, there was no significant difference at 6 months, when favorable symptom-status outcomes were seen in 23 of 25 treated patients (92%) and 18 of 22 controls (81.8%) (table 4). Nor were there any significant differences between the two groups with regard to Hallpike testing at either followup.
Many neurotologists believe that canalith repositioning therapy is beneficial in treating BPPV, while others believe that the disease resolves spontaneously. When Blakley reported that canalith repositioning did not result in any significant difference in outcomes in his randomized, controlled trial, he noted that patients with BPPV tended to improve over 2 or 3 months after onset, regardless of whether any treatment had been undertaken. 
In our study, we found significant differences in outcomes in both subjective and objective measures during the first month following treatment, but none afterward. A high percentage of patients in both groups experienced symptom relief. We continue to follow these patients.
A particularly interesting finding in our study was that unfavorable outcomes were seen in both groups. At 6 months, 8.0% of the treated patients and 18.2% of the control group had not improved either subjectively or objectively (table 4). Patients who fail therapy should be considered for repeat treatment or surgery.
From the Department of Otolaryngology, Chulalongkorn University, Bangkok.
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|Publication:||Ear, Nose and Throat Journal|
|Date:||Sep 1, 2000|
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