Canal switch: a possible complication of physical therapeutic manoeuvers for posterior canal benign paroxysmal positional vertigo

Objective

To study the frequency of canal switch in posterior canal benign paroxysmal positional vertigo (BPPV) treated by canalith repositioning manoeuver (CRP), quick liberatory rotation manoeuver (QLR) or Semont manoeuver (SM).

Methods

Retrospective study on 1158 patients, 637 women and 521 men suffering from geotropic posterior canal BPPV treated by CRP, QLR, or SM, retested after 15 minutes and about seven days.

Results

1146 patients recovered from the acute phase; treatments failed in 12 patients treated with CRP. We observed 12 canal switches from posterior to lateral canal and 2 from posterior to anterior canal during or after CRP in 13/879 cases (1.5%) and after QLR in 1/158 (0.6%) with no significant difference between CRP vs SM and QLR. We did not consider slight positional downbeat nystagmus after the therapeutic manoeuvers as a sign of canal switch into the anterior canal, but as a sign of persistent small debris in the non-ampullar arm of the posterior canal.

Conclusions

Canal switch is rare for any manoeuver and it does not belong to the criteria to choose one manoeuver over another. Notably, due to the canal switching criteria, SM and QLR cannot be preferred over those with a more prolonged extension of the neck.

Comparison of the efficacy of the Epley maneuver and repeated Dix-Hallpike tests for eliminating positional nystagmus: A multicenter randomized study

Background and objectives

Patients with benign paroxysmal positional vertigo of the posterior canal (pc-BPPV) exhibit BPPV fatigue, where the positional nystagmus diminishes with the repeated performance of the Dix-Hallpike test (DHt). BPPV fatigue is thought to be caused by the disintegration of lumps of otoconial debris into smaller parts and can eliminate positional nystagmus within a few minutes [similar to the immediate effect of the Epley maneuver (EM)]. In this study, we aimed to show the non-inferiority of the repeated DHt to the EM for eliminating positional nystagmus after 1 week.

Methods

This multicenter, randomized controlled clinical trial was designed based on the CONSORT 2010 guidelines. Patients who had pc-BPPV were recruited and randomly allocated to Group A or Group B. Patients in Group A were treated using the EM, and patients in Group B were treated using repeated DHt. For both groups, head movements were repeated until the positional nystagmus had been eliminated (a maximum of three repetitions). After 1 week, the patients were examined to determine whether the positional nystagmus was still present. The groups were compared in terms of the percentage of patients whose positional nystagmus had been eliminated, with the non-inferiority margin set at 15%.

Results

Data for a total of 180 patients were analyzed (90 patients per group). Positional nystagmus had been eliminated in 50.0% of the patients in Group A compared with 47.8% in Group B. The upper limit of the 95% confidence interval for the difference was 14.5%, which was lower than the non-inferiority margin.

Discussion

This study showed the non-inferiority of repeated DHt to the EM for eliminating positional nystagmus after 1 week in patients with pc-BPPV and that even the disintegration of otoconial debris alone has a therapeutic effect for pc-BPPV. Disintegrated otoconial debris disappears from the posterior canal because it can be dissolved in the endolymph or returned to the vestibule via activities of daily living.

Classification of evidence

This study provides Class II evidence of the non-inferiority of repeated DHt to the EM for eliminating positional nystagmus after 1 week.

Registration number

UMIN000016421.

Clinical Characteristics of persistent geotropic horizontal direction-changing positional nystagmus: Experience in 189 participants

BACKGROUND

The etiology and mechanism of persistent geotropic horizontal direction-changing positional nystagmus (DCPN) are still unclear. Whether this pattern of nystagmus is a subtype of benign paroxysmal positional vertigo (BPPV) remains controversial.

OBJECTIVE

The goal of this study was to observe the clinical characteristics of persistent geotropic horizontal DCPN involving the lateral semicircular canal.

METHODS

The analysis was performed to participants with episodic positional vertigo in our clinic from 2014 to 2021. Participants were included via positional test. We observed and summarized the distribution data, vertigo history, follow-up tests, and recurrence situations of 189 persistent geotropic horizontal DCPN participants.

RESULTS

The mean age at the first time showing of persistent geotropic horizontal DCPN was 56±14.7 and more women than men were affected by persistent geotropic horizontal DCPN (female-to-male ratio 2.4 : 1). Overall, 58.7% (57/94) of participants who came for the first-week follow-up test were asymptomatic. Thirty-three participants experienced recurrence (female-to-male ratio: 4.5 : 1). Fifty-three (28.0%) participants experienced the conversion of the patterns of DCPN in the history, the follow-up tests and the recurrence compared to the first showing of persistent geotropic horizontal DCPN. 24(12.1%) participants still experienced persistent geotropic horizontal DCPN attack in the follow-up tests and the recurrences without benign paroxysmal positional vertigo history.

CONCLUSION

Persistent geotropic horizontal DCPN affected more women than men. The persistent geotropic horizontal DCPN that with conversion to transient geotropic horizontal DCPN or to persistent apogeotropic horizontal DCPN might be a subtype of BPPV or in a stage of BPPV process. However, the persistent geotropic horizontal DCPN without conversion might be an independent disease that is not related to BPPV.

[Effects of age and involved semicircular canals on the caloric test in patients with primary horizontal semicircular canal benign paroxysmal positional vertigo]

Objective:To investigate the effects of age and involved semicircular canals on the results of caloric test in patients with primary horizontal semicircular canal benign paroxysmal positional vertigo（BPPV）. Methods:A total of 258 patients conforming to the diagnosis of primary horizontal semicircular canal BPPV were selected as the case group, and another 110 non-BPPV patients with dizziness/vertigo as the main complaint were selected as the control group. Both groups were divided into elderly group and young and middle-aged group according to their age, and the general information and the results of the caloric test were compared and analyzed for each group. Results: ①There was no statistically significant difference in gender composition and type of involved semicircular canal between the different age groups（P>0.05）；②In patients with horizontal semicircular canal canalolithiasis, there was no statistically significant difference in the rate of abnormal caloric test results between the different age groups（P>0.05）；③In patients with horizontal semicircular canal cupulolithiasis, there was a statistically significant difference in the rate of abnormal caloric test results between the different age groups（P<0.05）；④In the same age group, there was no statistically significant difference in the rate of abnormal caloric test results between the patients with horizontal semicircular canal canalolithiasis and the patients with cupulolithiasis（P>0.05）；⑤In the control group, there was no statistically significant difference between the different age groups in gender composition（P>0.05）；⑥In the control group, there was a statistically significant difference in the rate of abnormal caloric test results between the different age groups（P<0.05）；⑦Among the patients in the same age group, there was no statistically significant difference in the age distribution between the case and control groups（P>0.05）；⑧In patients of the same age group, there was no statistically significant difference in the rate of abnormal caloric test results between the case and control groups（P>0.05）. Conclusion:The involvement of the semicircular canal does not affect the results of the caloric test, but age can affect the results, especially in BPPV patients with horizontal semicircular canal cupulolithiasis.

The clinical significance of direction-fixed mono-positional apogeotropic horizontal nystagmus

Objective

A mono-positional persistent, direction-fixed apogeotropic nystagmus (MPosApoNy) is very challenging for the neuro-otologist. MPosApoNy can be found in patients suffering from a partially compensated acute unilateral vestibulopathy; with a normal caloric test, one can speculate the presence of “trapped” otolithic debris located close to the ampulla of the horizontal semicircular canal.

Methods

Among 957 patients suffering from vertigo and dizziness, we selected 53 cases of MPosApoNy.

Results

In 28 patients, caloric test showed a canal paresis on the same side of the MPosApoNy. In the remaining 25 cases, MPosApoNy was the only clinical finding. We hypothesised the presence of horizonal canal lithiasis and patients were treated with a Gufoni manoeuvre, followed by a forced prolonged position.

Conclusions

Performing bedside examination in a patient suffering from vertigo, the presence of MPosApoNy may be due to: a) facilitation of a subclinical nystagmus due to the mechanism of apogeotropic reinforcement; b) horizontal canal lithiasis with ‘trapped’ otoliths close to the ampulla. The disappearance of MPosApoNy following a repositioning manoeuvre or conversion in a typical form of canalolithiasis may represent the best method to confirm this hypothesis.

Variants of benign paroxysmal positional vertigo in relation to head position during sleep

BACKGROUND

Patients with posterior- and lateral-(canal)-benign paroxysmal positional vertigo (BPPV)-canalolithiasis sleep in the affected-ear-down head position. Posterior-BPPV-canalolithiasis typically affects the right than left ear; sleeping in the right-ear-down head position may be causal.

OBJECTIVE

To investigate the relationship between habitual head position during sleep and the onset of BPPV variants.

METHODS

Among 1,170 cases of BPPV variants with unknown etiology, the affected ears, habitual head positions during sleep based on interviews, and relationships among them were investigated.

RESULTS

Posterior-BPPV-canalolithiasis and lateral-BPPV-canalolithiasis-geotropic affected the right ear significantly more often. Significantly more patients with posterior-BPPV-canalolithiasis and lateral-BPPV-canalolithiasis-apogeotropic habitually slept in the right-ear-down head position. Patients with posterior- and lateral-BPPV-canalolithiasis and light cupula were more likely to sleep habitually in the affected-ear-down position than in the healthy-ear-down head position; no relationship was observed in patients with posterior- and lateral-BPPV-cupulolithiasis. In patients with posterior-BPPV-canalolithiasis and lateral-BPPV-canalolithiasis-geotropic, the proportion of right-affected ears in those sleeping habitually in the right-ear-down head position was significantly greater than that for the left-affected ear.

CONCLUSIONS

A habitual affected-ear-down head position during sleep may contribute to BPPV-canalolithiasis and light cupula onset, but not BPPV-cupulolithiasis onset. However, habitual sleeping in the right-ear-down head position cannot explain the predominance of right-affected ears.

Effect of Sitting Position vs. Supine Position With the Head Turned to the Affected Side on Benign Paroxysmal Positional Vertigo Fatigue

Objective: In benign paroxysmal positional vertigo (BPPV), positional nystagmus becomes generally weaker when the Dix–Hallpike test is repeated. This phenomenon is termed BPPV fatigue. We previously reported that the effect of BPPV fatigue deteriorates over time (i.e., the positional nystagmus is observed again after maintaining a sitting head position). The aim of this study was to investigate whether the effect of BPPV fatigue attenuates after maintaining a supine position with the head turned to the affected side.

Methods: Twenty patients with posterior-canal-type BPPV were assigned to two groups. Group A received Dix–Hallpike test, were returned to the sitting position (reverse Dix–Hallpike test) with a sitting head position for 10 min, and then received a second Dix–Hallpike test. Group B received Dix–Hallpike test, were kept in the supine position with the head turned to the affected side for 10 min, and then received reverse Dix–Hallpike test followed by the second Dix–Hallpike test. The maximum slow phase eye velocity (MSPEV) of positional nystagmus induced by the first, reverse, and second Dix–Hallpike test were analyzed.

Results: The ratio of MSPEV of the positional nystagmus induced by the second Dix–Hallpike test relative to the first Dix–Hallpike test was significantly smaller in group B than that in group A. There was no difference in the MSPEV of the positional nystagmus induced by the reverse Dix–Hallpike test between group A and B.

Conclusions: The effect of BPPV fatigue is continued by maintaining a supine position with the head turned to the affected side, while the effect is weakened by maintaining a sitting head position. On the basis of the most widely accepted theory of the pathophysiology of BPPV fatigue, in which the particles become dispersed along the canal during head movement in the Dix–Hallpike test, we found an inconsistency whereby the dispersed otoconial debris return to a mass during the sitting position but do not return to a mass in the supine position with the head turned to the affected side. Future studies are required to determine the exact pathophysiology of BPPV fatigue.

Classification of Evidence: 2b.

Less common forms of posterior canal benign paroxysmal positional vertigo

The most common form of posterior canal benign paroxysmal positional vertigo (BPPV) is characterised by positional, paroxysmal, upbeat nystagmus, with a torsional component beating towards the downward ear. Rarer variants have been reported, putatively due to either the position of otoconia in the canal or anatomic variations of the semicircular canals. The most frequent less common form is apogeotropic posterior canal BPPV, in which the positional nystagmus is downbeat and torsional apogeotropic. In this form, the main problems are differential diagnosis with central mimics of BPPV and identification of the affected canal and its side. The authors propose a new subtype of apogeotropic posterior canal BPPV hypothesising the localization of otoconia in the ampullary tract of the affected canal, which might explain the modality of the conversion in typical posterior canal BPPV which they observed in some of these cases. If nystagmus of the less common forms of posterior canal BPPV is explicable through purely peripheral mechanisms, these forms should no longer be defined as “atypical” but, in a less demanding way, as “less common” variants, which must be recognised by any expert otoneurologist.

Sémont Maneuver for Benign Paroxysmal Positional Vertigo Treatment: Moving in the Correct Plane Matters

HYPOTHESIS

We aimed to investigate the effect of the head excursion angle on the success of the Sémont Maneuver (SM).

BACKGROUND

SM is performed with the head turned by 45 degrees toward the unaffected ear. In clinical routine, it is unlikely that physicians can turn the head to a position of exactly 45 degrees. Moreover, it is unclear how possible deviations from 45 degrees would affect the outcome with SM.

METHODS

We used an in vitro model (upscaled by ×5) of a posterior semicircular canal with canalithiasis to study head excursion angles (0-75 degrees) and minimum waiting times in SM. Additionally, we measured actual head excursion angles performed by trained physicians during SM on a healthy subject.

RESULTS

Successful canalith repositioning to the utricle was possible at head excursion angles between 21 and 67 degrees. Waiting time increased from 16 to 30 seconds with increasing deviation from 45 degrees. Angles larger than 67 degrees or smaller than 21 degrees did not lead to successful repositioning even after a waiting period of 5 minutes. Physicians set head excursion angles of 50 degrees ±SD 4.8 degrees while performing the SM.

CONCLUSION

Angular deviations up to ±20 degrees from the ideal SCC plane (45 degrees) still allows for successful SM. Although the tested physicians tended to underestimate the actual head excursion angle by 5 degrees (and more), the success of SM will not be affected provided that the waiting time is sufficiently long. Further, the results suggest that the Brandt-Daroff maneuver is a form of habituation training rather than a liberatory maneuver.

The Video Head Impulse Test in the acute stage of posterior canal benign paroxysmal positional vertigo

OBJECTIVE

Study the high-frequency vestibulo-oculomotor reflex in posterior canal benign paroxysmal positional vertigo (BPPV) through Video Head Impulse Test (vHIT).

METHODS

150 patients suffering for the first time from posterior canal BPPV were studied. Posterior canal vestibulo ocular reflex (VOR) gain was analysed through stimulations in right anterior-left posterior and left anterior-right posterior planes before treatment, immediately after resolution of the acute stage and one month later. Results were compared with a group of 100 healthy individuals.

RESULTS

No significant difference between the study the control groups was observed, except for normalised asymmetry ratio of the posterior canal which was significantly higher in the study group. VOR gains of both affected posterior canals and contralateral healthy posterior canals were not significantly correlated with the VOR gain of ipsilateral and contralateral anterior canals.

CONCLUSIONS

vHIT does not seem to represent an essential tool to study typical posterior canal BPPV in patients affected by this disease for the first time. Different results might be expected in relapsing forms, non-responsive forms, long lasting forms, or atypical variants in which major damage could be provoked by the persistence of otoconia in the canal or by its complete or partial jam.

Congruous Torsional Down Beating Nystagmus in the Third Position of the Semont's Maneuver in Patients Treated for Canalithiasis of Posterior Semicircular Canal Benign Paroxysmal Positional Vertigo: Its Significance and Prognostic Value

Due to its mechanical pathogenesis, benign paroxysmal positional vertigo treatment is mainly physical: when posterior semicircular canal is involved, Semont's maneuver is reported as one of the most effective liberating procedures. In the case of a canalolithiasis, the efficacy of the maneuver is corroborated by the appearance of some nystagmus findings during its performance. Liberating nystagmus, that can occur in the second position of Semont's maneuver and whose direction is congruous with the excitation of the affected posterior semicircular canal has proven to be a favorable prognostic sign. On the other hand, in clinical experience, we've frequently verified the appearance of another nystagmus during the execution of the maneuver: upon reaching the third position, when replacing the patient seated, a torsional down beating nystagmus, with the torsional component “congruous” with the stimulation of the vertical semicircular canals of the affected side, can often be appreciated. Such a sign can occur with or without having had the previous liberating nystagmus in the second position and is almost always associated with an intense vertigo and/or body pulsion. In this study, we describe the incidence and characteristics of the congruous torsional down beating nystagmus that can arise by assuming the third position of Semont's maneuver in a cohort of patients treated for posterior semicircular canal benign paroxysmal positional vertigo due to canalolithiasis. In the best of our knowledge, such a sign has never been described and explained before. On the basis of the pathophysiology and of the possible canal receptors stimulation during the different phases of Semont's maneuver, we formulated different hypothesis on how such a nystagmus can be generated. We observed that such a sign, when elicited, has a very good prognostic meaning for healing purposes, even better than that of liberating nystagmus. Therefore, congruous torsional down beating nystagmus should always be checked when performing Semont's maneuver because it could help in predicting success of physical treatment and in managing patients.

Management of Lateral Semicircular Canal Benign Paroxysmal Positional Vertigo

Benign paroxysmal positional vertigo (BPPV) is the most common cause of peripheral vestibular vertigo. It is caused by free-floating otoconia moving freely in one of the semicircular canals (canalolithiasis) or by otoliths adhered to the cupula (cupulolithiasis). The posterior canal is the most common canal affected, followed by the lateral canal. Diagnosis of the side affected is critical for successful treatment; therefore, suppressing visual fixation is essential to examination of these patients' eye movement. On the basis of our experience, we have adopted the Zuma maneuver and the modified Zuma maneuver for both apogeotropic and geotropic variants of lateral canal BPPV. Knowledge of the anatomy and pathophysiologic mechanisms of the semicircular canals is essential for correct management of these patients. Hence, using a single maneuver and its modification may facilitate daily neurotological practice.

A case of apogeotropic horizontal canal benign paroxysmal positional vertigo that transformed to the geotropic variant during treatment with Appiani maneuver, followed by successful treatment with Gufoni maneuver

Lesions at three possible sites can masquerade as apogeotropic horizontal semicircular canal benign paroxysmal positional vertigo (HSC-BPPV), namely: 1) short anterior (ampullary) arm canalolithiasis; and 2) culpulolithiasis, which may be either canal (Cup-C) or utricle-sided (Cup-U). There are no clinical methods or investigations to determine the exact pathological site when a patient with a history compatible with HSC-BPPV is found to have apogeotropic positional nystagmus on the supine roll test. Therefore, the treatment of apogeotropic variant of HSC-BPPV not only poses difficulties but the therapeutic options need to be tailored according to the ostensible localization of the pathology. If the apogeotropic HSC-BPPV is transformed into the geotropic variant, it becomes relatively easier to treat, as the treatment options for the latter are very well established. There are reports of cases of the apogeotropic variant of HSC-BPPV being transformed inadvertently during diagnostic positional tests as well as during therapeutic (intention-to-treat) positional maneuvers. I report here a case of an apogeotropic variant of right HSC-BPPV, that transformed into a geotropic variant during the therapeutic (intention-to-treat) Appiani maneuver, which was subsequently successfully treated with two sequences of Gufoni maneuver after transformation. The patient was followed up at one and 24 hours after the second sequence of Gufoni maneuver with a diagnostic supine roll test, which was negative. The case report is supported by seven videos of the diagnostic and therapeutic positional maneuvers revealing positional nystagmus, its appearance, change, and disappearance as clinical events unfolded during the examination and treatment.

Effects of Interval Time of the Epley Maneuver on Immediate Reduction of Positional Nystagmus: A Randomized, Controlled, Non-blinded Clinical Trial

Objective: The Epley maneuver (EM) has an immediate effect: rapid reduction of positional nystagmus. Benign paroxysmal positional vertigo (BPPV) causes BPPV fatigue, which constitutes fatigability of positional nystagmus and vertigo with repeated performance of the Dix-Hallpike test; notably, BPPV fatigability becomes ineffective over time. We hypothesized that the immediate effect of the EM is caused by BPPV fatigue. Therefore, we suspected that performance of the EM with intervals between head positions would worsen the immediate reduction of positional nystagmus in patients with BPPV, because BPPV fatigability would become ineffective during performance of this therapy.

Methods: Forty patients with newly diagnosed BPPV were randomly assigned to the following two groups; one group performed the EM without intervals between positions (group A), and the other group performed the EM with 3 min intervals between positions (group B). The primary outcome measure was the ratio of maximum slow-phase eye velocity (MSPEV) of positional nystagmus soon after the EM, compared with that measured before the EM. Secondary outcome included whether a 30 min interval after the EM enabled recovery of MSPEV of positional nystagmus to the original value. This study followed the CONSORT 2010 reporting standards.

Results: In both groups A and B, the immediate effect of the EM could be observed, because MSPEV during the second Dix-Hallpike test was significantly smaller than MSPEV during the first Dix-Hallpike test (p < 0.0001 in group A, p < 0.0001 in group B). The primary outcome measure was larger in group B than in group A (p = 0.0029). The immediate effect faded 30 min later (secondary outcome).

Conclusions: This study showed that the EM had an immediate effect both with and without interval time in each head position of the EM. Because setting interval time in each head position of the EM reduced the immediate effect of the EM, interval time during the EM adds less benefit. This finding can reduce the effort exerted by doctors, as well as the discomfort experienced by patients with pc-BPPV, during EM. However, this immediate effect may be caused by BPPV fatigue, and may fade rapidly.

Classification of Evidence: 1b

Difference in Serum Levels of Vitamin D Between Canalolithiasis and Cupulolithiasis of the Horizontal Semicircular Canal in Benign Paroxysmal Positional Vertigo

Background and Purpose: In the horizontal canal benign paroxysmal positional vertigo (BPPV), cupulolithiasis shows apogeotropic direction changing nystagmus lasting more than 1 min, while canalolithiasis leads to geotropic direction changing nystagmus lasting < 1 min. The difference between cupulolithiasis and canalolithiasis is widely accepted to be the attachment of the displaced otoconia to the cupula of a semicircular canal. Several studies have shown a relationship between BPPV and vitamin D deficiency, but no studies have compared serum levels of vitamin D between canalolithiasis and cupulolithiasis patients. The purpose of this study was to clarify the difference in vitamin D serum level between canalolithiasis and cupulolithiasis of the horizontal canal.

Methods: This retrospective study included 20 and 15 patients with canalolithiasis and cupulolithiasis of the horizontal canal, respectively. Serum levels of 25-hydroxyvitamin D [25(OH)D] during the acute phase of BPPV were measured.

Results: The mean 25(OH)D serum level in patients with canalolithiasis and cupulolithiasis was 13.2 ± 1.4 and 20.4 ± 1.6 ng/mL, respectively, and the difference was statistically significant (p = 0.0014), also after adjusting for age and sex (p = 0.0351). Eighteen out of 20 (90%) and 5 of 15 (33%) patients were diagnosed with vitamin D deficiency in the canalolithiasis and cupulolithiasis groups, respectively, and this difference was also statistically significant (p = 0.0005).

Conclusion: We found that serum vitamin D level in patients with canalolithiasis was significantly lower than that in patients with cupulolithiasis of the horizontal canal.

[Benign paroxysmal positional vertigo: modern concepts of its etiology and pathogenesis]

The objective of the present review of the literature is the analysis of the currently available data concerning etiology and pathogenesis of benign paroxysmal positional vertigo (BPPV). The special emphasis is placed on the modern hypotheses of BPPV formation that collectively account for not more than 15% of all known cases of this condition. The best explored are the following causes of benign paroxysmal positional vertigo: vestibular neuronitis, head injuries, and disorders in the middle ear. During the recent years, much attention has been given to the role of disturbances of calcium metabolism and osteoporosis in etiology of benign paroxysmal positional vertigo. It is supposed that pathogenesis of vertiginous attacks can be explained in terms of the canalolithiasis and cupulolithiasis theories.

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.

Determinants for a Successful Sémont Maneuver: An In vitro Study with a Semicircular Canal Model

Objective

To evaluate the effect of time between the movements/steps, angle of body movements as well as the angular velocity of the maneuvers in an in vitro model of a semicircular canal (SCC) to improve the efficacy of the Sémont maneuver (SM) in benign paroxysmal positional vertigo.

Materials and Methods

Sémont maneuvers were performed on an in vitro SCC model. Otoconia trajectories were captured by a video camera. The effects of time between the movements, angles of motion (0°, 10°, 20°, and 30° below the horizontal line), different angular velocities (90, 135, 180°/s), and otoconia size (36 and 50 μm) on the final position of the otoconia in the SCC were tested.

Results

Without extension of the movements beyond the horizontal, the in vitro experiments (with particles corresponding to 50 μm diameter) did not yield successful canalith repositioning. If the movements were extended by 20° beyond the horizontal position, SM were successful with resting times of at least 16 s. For larger extension angles, the required time decreased. However, for smaller particles (36 μm), the required time doubled. The angular maneuver velocity (tested between 90 and 180°/s) did not have a major impact on the final position of the otoconia.

Interpretation

The two primary determinants for success of the SM are the time between the movements and the extension of the movements beyond the horizontal. The time between the movements should be at least 45 s. Angles of 20° or more below horizontal line (so-called Sémont+) should increase the success rate of SM.

Benign paroxysmal positional vertigo and its variants

Benign paroxysmal positional vertigo is a common labyrinthine disorder caused by a mechanic stimulation of the vestibular receptors within the semicircular canals. It is characterized by positional vertigo and positional nystagmus, both provoked by changes in the position of the head with respect to gravity. The social impact of the disease and its direct and indirect costs to healthcare systems are significant owing to impairment of daily activities and increased risk of falls. The first description of a patient with benign paroxysmal positional vertigo is from Robert Bárány in 1921, but the features of the syndrome and the diagnostic maneuver were well described by Dix and Hallpike in 1952. Since then, the gradually increasing interest of otolaryngologists and neurologists has led to a progressive advance in the knowledge of this labyrinthine disorder with regard to its epidemiologic, pathophysiologic, clinical, and therapeutic aspects. Despite the often effective diagnosis and treatment of most cases of benign paroxysmal positional vertigo, the physiopathologic explanations of the disease are mainly speculative. In this chapter, we describe the epidemiologic, pathophysiologic, clinical, and therapeutic aspects of benign paroxysmal positional vertigo.

Typical and atypical benign paroxysmal positional vertigo: literature review and new theoretical considerations

Atypical variants of benign paroxysmal positional vertigo (BPPV) are often encountered and frequently confusing. The authors present a hypothetical framework that accounts for all classical patterns of BPPV and several unusual variants such as BPPV without nystagmus, BPPV with downbeat nystagmus and BPPV with paradoxically direction-changing nystagmus. The authors introduce new concepts, such as "ipsicanal switch" and "horizontal short arm canalolithiasis" and suggest that their use may improve diagnosis and treatment in everyday clinical practice. The possible consequences of saccular otoconia detachment are reviewed according to the literature.

Efficacy and safety of semicircular canal occlusion for intractable horizontal semicircular benign paroxysmal positional vertigo

BACKGROUND

Some studies have suggested that semicircular canal occlusion is effective and safe for treating intractable posterior semicircular benign paroxysmal positional vertigo (PSC-BPPV), and adverse effects of canal occlusions for intractable horizontal semicircular BPPV (HSC-BPPV) were rarely reported. The aim of this study was to retrospectively discuss the efficacy of semicircular canal occlusion for intractable HSC-BPPV with at least 2 years of follow-up.

METHODS

From 2000 to 2011, 3 female patients (average age=60±6.9 years), with a diagnosis of HSC-BPPV refractory to head-shake and barbecue roll maneuver, underwent semicircular canal occlusion treatment in our hospital. The supine roll test was performed to diagnose HSC-BPPV and evaluate the treatment efficacy.

RESULTS

All patients with intractable HSC-BPPV had complete resolution of their positional vertigo after semicircular canal occlusion with a negative supine roll test. All patients reported transient postoperative disequilibrium, nausea, and vomiting, which resolved within 2 weeks. In addition, 1 patient (33.3%) had transient tinnitus, which resolved after 4 months. There were no other significant long-term complications.

CONCLUSION

Semicircular canal occlusion appears to be a safe and well-tolerated treatment modality for intractable HSC-BPPV. However, further studies with large sample sizes are needed to confirm our conclusion.

Clinical evaluation of posterior canal benign paroxysmal positional vertigo

BACKGROUND

Benign paroxysmal positional vertigo (BPPV) is a mechanical peripheral vestibular disorder which may involve any of the three semicircular canals but principally the posterior. In as much as the literature has described theories to explain the mechanism of BPPV and also contains scholarly works that elucidate BPPV; its management remains an enigma to most clinicians. To this end, this work was aimed at outlining an evidence-based best practice for most common form of BPPV.

MATERIALS AND METHODS

A systematic review of the literature was conducted between 1948 and June 2011 in PubMed, Embase, Ovid, and Cochrane database through the online Library of the University of Cape Town. Seventy-nine worthy articles that addressed the study were selected on consensus of the two authors.

CONCLUSION

There is consensus for the use of canalith repositioning procedures as the best form of treatment for posterior canal canalolithiasis. However, successful treatment is dependent on accurate identification of the implicated canal and the form of lithiasis. Furthermore, clinicians should note that there is no place for pharmacological treatment of BPPV; unless it is to facilitate repositioning.

Converting apogeotropic into geotropic lateral canalolithiasis by head-pitching manoeuvre in the sitting position

Liberatory treatment of lateral canalolithiasis is more effective for the geotropic, than for the apogeotropic forms and, therefore, it is worthwhile attempting to convert the apogeotropic forms into the geotropic forms. In 36 cases of apogeotropic lateral canalolithiasis, one to five Head-Pitch Manoeuvres were performed in the sitting position (Head-Pitch Test) in the attempt to transform apogeotropic into geotropic lateral canalolithiasis. The Head Pitch Test was performed by a quick 60 degrees forward-flexion and a slow maximal backward-extension of the head. The Head-Pitch Test was effective in 36.1% of cases, less than the repeated Head-Rolling in the supine position, but it was always well tolerated by patients. The quick 60 degrees forward-flexion of the head can evoke a horizontal nystagmus beating towards the healthy side in apogeotropic lateral canalolithiasis and towards the affected side in geotropic lateral canalolithiasis (Bow Nystagmus). Slow backward-extension of the head can evoke a horizontal nystagmus beating towards the affected side in apogeotropic lateral canalolithiasis and toward the healthy side in geotropic lateral canalolithiasis (Lean Nystagmus). Conversion from apogeotropic to geotropic lateral canalolithiasis by the Head-Pitch Test was effective when Bow and Lean Nystagmus changed directions or when the Head-Pitch Test evoked Bow Nystagmus toward the affected side and Lean Nystagmus toward the healthy side. Conversion occurred in 10 patients during the 60 degrees forward-flexion of the head. In contrast, in 3 patients, it occurred during extension of the head, when a "Lean Nystagmus" toward the healthy side appeared. In addition, Pseudospontaneous Nystagmus and Positioning Nystagmus that arose when the patient moved from the sitting to the supine position changed direction or were evoked ex-novo, both directed toward the healthy side. In all cases, Pagnini-McClure diagnostic manoeuvre confirmed the transformation with a Positional Paroxysmal Horizontal Geotropic Nystagmus, which was more intense when the affected ear was brought down. The Head-Pitch Test can be used as the method of choice to transform apogeotropic into geotropic lateral canalolithiasis. However, anterior flexion of the head in the geotropic forms must be avoided since involuntary and harmful transformations from the geotropic into the apogeotropic form can occur, moving otoliths towards the anterior arm and cupula.