1

Introduction

Vertigo, dizziness and unsteadiness represent the most common symptoms requiring medical attention in industrialized countries, with a prevalence of 48.3% for vertigo, 39.1% for unsteadiness, and 35.6% for dizziness. These three symptoms are often correlated to each other, in fact, they arise two times out of three in various combinations rather than isolated, and 90% of episodes last less than 2 minutes .

The term “dizziness” implies a non-specific sensation of disorientation, in which the patient feels as if standing in a boat, unsteady, light-headed, foggy or drowsy. The term is often improperly used as a synonym for vertigo, whereas the two symptoms are expressions of two different pathogenetic processes. The incidence of dizziness in the general population ranges from 20% to 30% and it has been demonstrated that with every 5 years of age increase, there is a 10% increase in the probability of an elderly individual suffering from dizziness . It has been estimated that every year 7.5 million of patients suffering from dizziness in North America are evaluated in the primary care setting, in emergency departments and in specialized dizziness clinics . We can recognize the following as causes of dizziness: peripheral vestibular dysfunction (40%), central nervous system lesion (10%), psychiatric disorders (15%), presyncope/disequilibrium (25%) and non-specific dizziness (10%) . Benign paroxysmal positional vertigo (BPPV) accounts for 26% of all dizziness cases in older people . Although a cross-sectional study of a group of 100 elderly patients with multiple chronic conditions found a 9% prevalence of undiagnosed BPPV, the lifetime prevalence of BPPV was 2.4% and the its incidence was 0.6% .

About two-thirds of the patients successfully treated with the first canalith repositioning procedure (CRP) have residual dizziness that appears 24–72 hours after CRP and disappears within 3 months without a specific treatment in all cases; early CRP is thought to reduce the incidence of residual dizziness .

The reported rates of BPPV recurrence vary considerably, from 3.8% at 6 months to 50% in long-term follow-up ; however, some authors report rates from 50% to 80% in the first 6–12 months after the first CRP . This variation in recurrence rates depends on the different observational periods of the studies published to date, and on the attempt to demonstrate the existence of a correlation between BPPV recurrence and predisposing factors such as age, sex, patient risk factors, association with other conditions, type, number and timing of the performed treatments.

The aim of this study was to assess the possible correlation between BPPV recurrence and the repetition of a second CRP in subjects with post-CRP residual dizziness, and more specifically to investigate whether repeating CRPs prevents BPPV recurrence.

2

Material and methods

This retrospective study involved 292 patients who experienced a first episode of BPPV and were treated with a single type of CRP at the Ear, Nose, Throat Department in Trieste from January 2008 through December 2013. The patient selection criteria are summarized in Table 1 . The study protocol was approved by local ethics committee on clinical investigation.

Patients underwent routinely anamnestic evaluation, vestibular clinical examination with otoscopy, balance and posture tests (Romberg test, Unterberger test, Mingazzini test) and coordination tests (index finger to nose and heel to knee). According to evidence-based guidelines published in 2008 by the American Academy of Otolaryngology – Head and Neck Surgery , clinical examination included the Dix–Hallpike diagnostic maneuver to test the posterior semicircular canal (PSC); if a patient had a history compatible with BPPV and the Dix–Hallpike test is negative, the clinician should perform a supine roll test to assess for horizontal semicircular canal (HSC) BPPV. Further, we looked for onset of the provoked positional nystagmus by using Fresnel lenses.

According to the guidelines , we performed the Epley maneuver or the Lempert maneuver to treat posterior or horizontal semicircular canal BPPV, respectively as follows.

• •
  

  Dix–Hallpike diagnostic test is performed by bringing the patient from an upright seated position to a supine position with the head turned 45 degrees to one side and the neck extended 20 degrees. The patient may be slowly returned to the upright position, and a reversal of the nystagmus may be observed; the maneuver is then repeated for the other side .

  
  
• •
  

  Supine roll test is performed by initially positioning the patient supine with the head in neutral position followed by quickly rotating the head 90 degrees to one side to examine for characteristic nystagmus. Then the head is returned to the face-up position, allowing all nystagmus to subside. The head is then turned rapidly to the other side to examine for nystagmus once again .

At the routinely scheduled two-week recall, the patients were subjected to clinical examination and administered the Italian translation of the Dizziness Handicap Inventory (DHI) , a 25-item questionnaire which investigates objectively the psychological, physical, and practical aspects of dizziness. The score ranges from 0 (absence of symptoms) to 100 (maximum intensity of symptoms).

Patients were classified according to the following criteria based on the results of the clinical assessment:

• 1.
  

  Complete resolution: asymptomatic patient, no nystagmus nor vertigo and nausea during positional tests, DHI score <30;

  
  
• 2.
  

  Partial resolution: patients without nystagmus, vertigo and nausea during positional tests, but with DHI score >30 (dizzy patients);

  
  
• 3.
  

  Persistent BPPV: according to the guidelines , we considered BPPV as persistent when symptoms with nystagmus and/or vertigo and/or nausea continued for more than 2 weeks and whether BPPV relapsed 2 weeks after a complete resolution

  
  
• 4.
  

  Changing BPPV (canal switch): presence of nystagmus and/or vertigo and/or nausea evoked by positional tests but involving a different canal in the same labyrinth.

We decided to focus on groups 1 and 2 and in the latter we identified two subgroups depending on whether the patients underwent a second CRP or not: 94 had undergone a second CRP (treated group), while 84 patients had not (non-treated group). This distinction was made because there has been a progressive shift in our approach consequent to the publication of the clinical practice guidelines in 2008 , as we introduced the option to repeat a second CRP to treat patients with residual dizziness, instead of adopting an observational monitoring as in the past.

Three to four weeks after follow-up vestibular assessment, the patients underwent a clinical examination and they filled in the DHI questionnaire once again.

In order to analyze the recurrence rate of BPPV in dizzy patients, in January 2015, patients belonging to the groups 1 and 2 (complete and partial resolution) were individually contacted by the department staff to question them about possible BPPV relapses during the period passed from their first episode until 31 December 2013. Patients with persistent BPPV (group 3) or canal-switch BPPV (group 4) were not contacted because they had undergone more than one CRP with curative intent and they were not the focus of this study.

Statistical analysis was performed using dedicated software (Statistical Package for Social Sciences v.15, SPSS Inc., Chicago, IL). The rate of recurrence of BPPV was compared between the treated group and the non-treated group with a Pearson χ ² test. The survival analysis was carried out by Kaplan–Meier curves; a log-rank test was used to assess the difference in survival distribution between the groups. In consideration of the fact that the observational periods of this study started at different times, we applied the Kaplan–Meier product-limit method to estimate the survival function in order to determine whether the time to recurrence differed between the complete and the partial resolution groups and between the treated and non-treated groups. Survival time was defined as the number of days passed from the first treatment to the day in which the symptoms of BPPV recurred. For patients without BPPV recurrence, the timeline was censored at the last day of the observational period. The estimated survival functions were plotted for the groups with complete resolution and partial resolution, and for the treated group and non-treated group.

Furthermore, we estimated the degree of dizziness resolution, by comparing the DHI results obtained from the partial resolution group, and in relation to which semicircular canal was involved. In particular we considered dizziness recovery to be significant when patients passed from a DHI score >32 to a DHI score <30 after 4 weeks. The level of significance for all tests was p < 0.05.

2

Material and methods

This retrospective study involved 292 patients who experienced a first episode of BPPV and were treated with a single type of CRP at the Ear, Nose, Throat Department in Trieste from January 2008 through December 2013. The patient selection criteria are summarized in Table 1 . The study protocol was approved by local ethics committee on clinical investigation.

Patients underwent routinely anamnestic evaluation, vestibular clinical examination with otoscopy, balance and posture tests (Romberg test, Unterberger test, Mingazzini test) and coordination tests (index finger to nose and heel to knee). According to evidence-based guidelines published in 2008 by the American Academy of Otolaryngology – Head and Neck Surgery , clinical examination included the Dix–Hallpike diagnostic maneuver to test the posterior semicircular canal (PSC); if a patient had a history compatible with BPPV and the Dix–Hallpike test is negative, the clinician should perform a supine roll test to assess for horizontal semicircular canal (HSC) BPPV. Further, we looked for onset of the provoked positional nystagmus by using Fresnel lenses.

According to the guidelines , we performed the Epley maneuver or the Lempert maneuver to treat posterior or horizontal semicircular canal BPPV, respectively as follows.

• •
  

  Dix–Hallpike diagnostic test is performed by bringing the patient from an upright seated position to a supine position with the head turned 45 degrees to one side and the neck extended 20 degrees. The patient may be slowly returned to the upright position, and a reversal of the nystagmus may be observed; the maneuver is then repeated for the other side .

  
  
• •
  

  Supine roll test is performed by initially positioning the patient supine with the head in neutral position followed by quickly rotating the head 90 degrees to one side to examine for characteristic nystagmus. Then the head is returned to the face-up position, allowing all nystagmus to subside. The head is then turned rapidly to the other side to examine for nystagmus once again .

At the routinely scheduled two-week recall, the patients were subjected to clinical examination and administered the Italian translation of the Dizziness Handicap Inventory (DHI) , a 25-item questionnaire which investigates objectively the psychological, physical, and practical aspects of dizziness. The score ranges from 0 (absence of symptoms) to 100 (maximum intensity of symptoms).

Patients were classified according to the following criteria based on the results of the clinical assessment:

• 1.
  

  Complete resolution: asymptomatic patient, no nystagmus nor vertigo and nausea during positional tests, DHI score <30;

  
  
• 2.
  

  Partial resolution: patients without nystagmus, vertigo and nausea during positional tests, but with DHI score >30 (dizzy patients);

  
  
• 3.
  

  Persistent BPPV: according to the guidelines , we considered BPPV as persistent when symptoms with nystagmus and/or vertigo and/or nausea continued for more than 2 weeks and whether BPPV relapsed 2 weeks after a complete resolution

  
  
• 4.
  

  Changing BPPV (canal switch): presence of nystagmus and/or vertigo and/or nausea evoked by positional tests but involving a different canal in the same labyrinth.

We decided to focus on groups 1 and 2 and in the latter we identified two subgroups depending on whether the patients underwent a second CRP or not: 94 had undergone a second CRP (treated group), while 84 patients had not (non-treated group). This distinction was made because there has been a progressive shift in our approach consequent to the publication of the clinical practice guidelines in 2008 , as we introduced the option to repeat a second CRP to treat patients with residual dizziness, instead of adopting an observational monitoring as in the past.

Three to four weeks after follow-up vestibular assessment, the patients underwent a clinical examination and they filled in the DHI questionnaire once again.

In order to analyze the recurrence rate of BPPV in dizzy patients, in January 2015, patients belonging to the groups 1 and 2 (complete and partial resolution) were individually contacted by the department staff to question them about possible BPPV relapses during the period passed from their first episode until 31 December 2013. Patients with persistent BPPV (group 3) or canal-switch BPPV (group 4) were not contacted because they had undergone more than one CRP with curative intent and they were not the focus of this study.

Statistical analysis was performed using dedicated software (Statistical Package for Social Sciences v.15, SPSS Inc., Chicago, IL). The rate of recurrence of BPPV was compared between the treated group and the non-treated group with a Pearson χ ² test. The survival analysis was carried out by Kaplan–Meier curves; a log-rank test was used to assess the difference in survival distribution between the groups. In consideration of the fact that the observational periods of this study started at different times, we applied the Kaplan–Meier product-limit method to estimate the survival function in order to determine whether the time to recurrence differed between the complete and the partial resolution groups and between the treated and non-treated groups. Survival time was defined as the number of days passed from the first treatment to the day in which the symptoms of BPPV recurred. For patients without BPPV recurrence, the timeline was censored at the last day of the observational period. The estimated survival functions were plotted for the groups with complete resolution and partial resolution, and for the treated group and non-treated group.

Furthermore, we estimated the degree of dizziness resolution, by comparing the DHI results obtained from the partial resolution group, and in relation to which semicircular canal was involved. In particular we considered dizziness recovery to be significant when patients passed from a DHI score >32 to a DHI score <30 after 4 weeks. The level of significance for all tests was p < 0.05.