Benign paroxysmal positional nystagmus in hospitalized subjects receiving ototoxic medications.

OBJECTIVE: To investigate the occurrence of benign paroxysmal positional nystagmus in subjects undergoing treatment with potentially ototoxic medications. STUDY DESIGN: Prospective and retrospective record reviews. SETTING: Tertiary referral neurotology clinic; clinical research and technology center. SUBJECTS: Ninety-nine hospitalized subjects undergoing treatment of infectious disease or carcinoma with potentially ototoxic medications. INTERVENTIONS: Records review, tests of vestibular function. MAIN OUTCOME MEASURE: Results of Hallpike positional tests for benign paroxysmal positional nystagmus (electro-oculography). RESULTS: Forty-one (41%) of 99 subjects were female and 58 (59%) were male. Age range was 15 to 73 years (mean, 47 years). Forty-nine (50%) of 99 subjects had an unequivocally positive Hallpike test for benign paroxysmal positional nystagmus in one or both ears. The occurrence of benign paroxysmal positional nystagmus in the Hallpike-positive population was distributed equally across age decades. Of the 49 subjects with benign paroxysmal positional nystagmus, 22 (44%) were female and 27 (56%) were male. CONCLUSIONS: Benign paroxysmal positional nystagmus is the most common cause of vertigo in the general population, including subjects receiving ototoxic drugs. Complaints of vertigo in subjects receiving ototoxic drugs therefore may or may not indicate onset of ototoxicity. Occurrence of benign paroxysmal positional nystagmus in subjects receiving ototoxic drugs was independent of gender or age. The high occurrence rate of benign paroxysmal positional nystagmus in subjects receiving potentially ototoxic medications is consistent with the observation that benign paroxysmal positional nystagmus occurs in combination with many pathologic conditions. Benign paroxysmal positional nystagmus presenting in subjects receiving ototoxic drugs may complicate the clinical identification of ototoxicity and obfuscate clinical decision-making processes.     

Clinical characteristics of patients with multi-canal benign paroxysmal positional vertigo

IntroductionMulti-canal benign paroxysmal positional vertigo is considered to be a rare and controversial type in the new diagnostic guidelines of Bárány because the nystagmus is more complicated or atypical, which is worthy of further study.ObjectiveBased on the diagnostic criteria for multi-canal benign paroxysmal positional vertigo proposed by International Bárány Society, the study aimed to investigate the clinical characteristics, diagnosis and treatment of multi-canal benign paroxysmal positional vertigo.MethodsA total of 41 patients with multi-canal benign paroxysmal positional vertigo were included and diagnosed by Roll, Dix-Hallpike and straight head hanging tests. Manual reduction was performed according to the involvement of semicircular canals.ResultsAmong the 41 cases, 19 (46.3%) patients showed vertical up-beating nystagmus with or without torsional component and geotropic, apogeotropic horizontal nystagmus, and were diagnosed with posterior-horizontal canal. 11 (26.8%) patients showed vertical up-beating nystagmus with torsional component on one side and vertical down-beating nystagmus with or without torsional component on the other side during Dix-Hallpike test or straight head hanging test and were diagnosed with posterior-anterior canal benign paroxysmal positional vertigo 9 (26.8%) patients showed vertical down-beating nystagmus with or without torsional component and geotropic, apogeotropic horizontal nystagmus, and were diagnosed with anterior-horizontal canal 2 (4.9%) patients showed vertical geotropic torsional up-beating nystagmus on both sides and were diagnosed with bilateral posterior canal benign paroxysmal positional vertigo. High correlation between the sides with reduced vestibular function or hearing loss and the side affected by Multi-canal benign paroxysmal positional vertigo was revealed (contingency coefficient = 0.602, p = 0.010). During one-week follow up, nystagmus/vertigo has been significantly alleviated or disappeared in 87.8% (36/41) patients.ConclusionPosterior-horizontal canal benign paroxysmal positional vertigo was the most common type. Multi-canal benign paroxysmal positional vertigo involving anterior canal was also not uncommon. Caloric tests and pure tone audiometry may help in the determination of the affected side. Manual reduction was effective in most of Multi-canal benign paroxysmal positional vertigo patients.     

Subjective benign paroxysmal positional vertigo in patients with osteoporosis or migraine

IntroductionSubjective benign paroxysmal positional vertigo is a form of benign paroxysmal positional vertigo in which during the diagnostic positional maneuvers patients only present vertigo symptoms with no nystagmus.ObjectiveTo study the characteristics of subjects with subjective benign paroxysmal positional vertigo.MethodsProspective multicenter case-control study. All patients presenting with vertigo in the Dix-Hallpike test that presented to the participating hospitals were included. The patients were separated into two groups depending on whether nystagmus was present or not. An Epley Maneuver of the affected side was performed. In the follow-up visit, patients were checked to see if nystagmus and vertigo were present. Both groups of patients were compared to assess the success rate of the Epley maneuver and also to compare the presence of 19 variables.Results259 patients were recruited, of which 64 belonged to the subjective group. Nystagmus was eliminated in 67.2% of the patients with benign paroxysmal positional vertigo. 89.1% of the patients with subjective benign paroxysmal positional vertigo remained unaffected by nystagmus, thus showing a significant difference (p = 0.001). Osteoporosis and migraine were the variables which reached the closest to the significance level. In those patients who were taking vestibular suppressors, the percentage of subjective benign paroxysmal positional vertigo was not significantly higher.ConclusionsSubjective benign paroxysmal positional vertigo should be treated using the Epley maneuver. More studies are needed to establish a relationship between osteoporosis, migraine and subjective benign paroxysmal positional vertigo. The use of vestibular suppressants does not affect the detection of nystagmus.     

Horizontal canal paroxysmal positional vertigo (HCPPV) vs classical BPPV (new concepts about mechanism and domiciliary repositioning of particles)

Some new modificutiont of existing diagnostic and therapeutic manoeuvres (repositioning of particles) have been proposed, basing an the applications of the principles of hydrodynamics, inertial and gravitational forces in the semicircular canals. The above has been tried successfully on patients with benign paroxysmal positional vertigo (BPPV) and horizontal eanal paroxysmal positional vertigo (HCPPV) which can be executed by the patients themselves at home without the kelp of a therapist. Benign paroxysmal positional vertigo (BPPV) is a well-established entity whereas Horizontal Canal Paroxysmal Positional Vertigo (HCPPV) is a recently proposed one. In positional vertigo any canal may be involved. It is quite possible that in the past this diagnosis (HCPPV) was missed in many of the cases of positional vertigo. Kapfschuttel nystagmus (head-shaking nystanmas) is induced by side to side (to and fro) movements of the head around a vertical axis in the plane of the horizontal semicircular canal which is thought to be sensitise the labyrinth, Any manoeuvres that in induce nystagmus with or without vertino is hound to he a manifestation of an organic lesion and not a non-organic one. In a number of instances the postionul test Jor BPPV may yield negative results; but doing this test after kopfschuttel test a dormant positional nystagmus may appear on the surface i.e. uncovered in a number of cases which may have remained undetected if Kopfschutlel manoeuvre were not done. This implies- that by Kopfsi huttel test both the horizontal and vertical canals are sensitised. Moreover, Kopfschuttel nystaagmus is likely to be a manifestation of the horizontal canal stimulation, at leastin some cases, since the movements are executed in the plane of the horizontal canal (vide infra) when displaced otoconia impinges on the cupula /. crista bringing about its stimulation leading to vertigo and or nystagmus.     

Mechanism of posterior semicircular canal stimulation in patients with benign paroxysmal positional vertigo

A quantitative study of the stimuli and vestibulo-ocular response associated with benign paroxysmal positional vertigo (BPPV) was made to test and further develop the canalithiasis theory of BPPV. The angular velocities of the head in the planes of the semicircular canals during the Dix-Hallpike test were measured in four healthy subjects using electromagnetic sensors to record the position of the head in a six degrees of freedom paradigm. Next, the nystagmus reactions in seven patients diagnosed with idiopathic BPPV were recorded with video-oculography. The characteristics of the vestibulo-ocular reflex (VOR) response were analyzed using three-dimensional vector techniques. The angular velocity of the head was primarily, but not exclusively, in the plane of the posterior semicircular canal (PSC) in question. Both the anterior and horizontal canals were also stimulated by a lesser degree. The duration of the motion stimulus in the PSC was < 1.3 s with peak angular velocities of 150 deg/s. The eye response in BPPV patients began 4 s after the test and had a duration of 15-20 s. Peak slow-component eye velocities of about 42 deg/s were reached 3-5 s after onset of nystagmus. The motion of the eye, as predicted by the cupulolithiasis theory, is disconjugated and has torsional, vertical, and horizontal components. In the eye ipsilateral to the tested ear it is primarily torsional (0.80, 0.54, 0.16) and in the contralateral eye it is mainly vertical (0.57, 0.73, 0.08). These results suggest that particles, initially resting on the floor of the cupula dome in the PSC, are perturbed by the Dix-Hallpike test and disperse freely into the endolymph where they are propelled by gravity into the canal lumen. This creates abnormal pressure on the cupula and the specific VOR activation of the ipsilateral superior oblique and the contralateral inferior rectus muscles, whose force vectors are indistinguishable from the measured eye motion vectors. The estimated pressure exerted on the crista is approximately 10(-2) dyn/cm2.     

Posterior semicircular canal type benign paroxysmal positioning vertigo with ageotropic paroxysmal positioning nystagmus

We report on 3 patients with typical benign paroxysmal positioning vertigo (BPPV) and atypical, paroxysmal positioning nystagmus. When the Dix-Hallpike test was performed, the patients exhibited an ageotropic nystagmus, different from that classically described in posterior semicircular canal BPPV. It was torsional-vertical with the vertical component beating downwards, and the torsional component was beating away from the lowermost ear. In both left and right Dix-Hallpike positions, the upper poles of the eyes were turning away from the lowermost ear. The atypical ageotropic paroxysmal positional nystagmus of the posterior semicircular canal was observed in the evolution of the BPPV in 2 patients and on the first examination in the third. Two patients had changing patterns of paroxysmal positioning nystagmus.     

Ecological Aspects of Auditory Rehabilitation

A quantitative study of the stimuli and vestibulo-ocular response associated with benign paroxysmal positional vertigo (BPPV) was made to test and further develop the canalithiasis theory of BPPV. The angular velocities of the head in the planes of the semicircular canals during the Dix-Hallpike test were measured in four healthy subjects using electromagnetic sensors to record the position of the head in a six degrees of freedom paradigm. Next, the nystagmus reactions in seven patients diagnosed with idiopathic BPPV were recorded with video-oculography. The characteristics of the vestibulo-ocular reflex (VOR) response were analyzed using three-dimensional vector techniques. The angular velocity of the head was primarily, but not exclusively, in the plane of the posterior semicircular canal (PSC) in question. Both the anterior and horizontal canals were also stimulated by a lesser degree. The duration of the motion stimulus in the PSC was &;lt;1.3 s with peak angular velocities of 150 deg/s. The eye response in BPPV patients began 4 s after the test and had a duration of 15-20 s. Peak slow-component eye velocities of about 42 deg/s were reached 3-5 s after onset of nystagmus. The motion of the eye, as predicted by the cupulolithiasis theory, is disconjugated and has torsional, vertical, and horizontal components. In the eye ipsilateral to the tested ear it is primarily torsional (0.80, 0.54, 0.16) and in the contralateral eye it is mainly vertical (0.57, 0.73, 0.08). These results suggest that particles, initially resting on the floor of the cupula dome in the PSC, are perturbed by the Dix-Hallpike test and disperse freely into the endolymph where they are propelled by gravity into the canal lumen. This creates abnormal pressure on the cupula and the specific VOR activation of the ipsilateral superior oblique and the contralateral inferior rectus muscles, whose force vectors are indistinguishable from the measured eye motion vectors. The estimated pressure exerted on the crista is approximately 10^-2 dyn/cm².     

Epley maneuver and the head autorotation test in benign paroxysmal positional vertigo

The head autorotation tests can be affected with the dynamic changes within the semicircular canals caused by benign paroxysmal positional vertigo (BPPV). The vestibular autorotation test is a method of examining the VOR (especially the VOR that develops at higher frequencies like those that occur in the everyday environment). Twenty patients who had been diagnosed as having posterior semicircular canal BPPV were evaluated with head autorotation tests before and after the treatment maneuver. The head autorotation tests were performed just before the use of the Epley maneuver and after the resolution of symptoms and the typical nystagmus pattern. The mean gain values for horizontal rotation tests during the pre-treatment period were 0.823, 0.844, and 0.840 for the frequencies 1, 2, and 3 Hz, respectively. The mean gain values increased by 0.095 (95% confidence interval) with Epley’s maneuver. But this difference difference between the pre-treatment and post-treatment values was not statistically significant. All patients were also evaluated with vertical active tests. The differences between the pre-treatment and post-treatment values were not statistically significant in the vertical autorotation group. The phase values were within normal range in the horizontal and vertical rotation tests and remained so after the Epley maneuver. The stimulation of the VOR caused by BPPV did not affect gain and phase values to a statistically significant degree, and the values noted after the resolution of the patient’s symptoms improved slightly but without statistical significance.     

Dynamics of the vestibulo-ocular reflex in patients with the horizontal semicircular canal variant of benign paroxysmal positional vertigo

OBJECTIVE: Two types of direction-changing positional nystagmus, the geotropic and apogeotropic variants, are observed in patients with the horizontal semicircular canal (HSCC) type of benign paroxysmal positional vertigo (H-BPPV). In this study, we assessed the dynamics of the vestibulo-ocular reflex (VOR) of the HSCC in patients with H-BPPV. MATERIAL AND METHODS: Patients were rotated about the earth-vertical axis at frequencies of 0.1, 0.3, 0.5, 0.7 and 1.0 Hz with a maximum angular velocity of 50 degrees/s. Eye movements were recorded on a video imaging system using an infrared charge-coupled device (CCD) camera, and our new technique for analyzing the rotation vector of eye movements in three dimensions was used. RESULTS: In the patients with geotropic positional nystagmus, there were no differences in VOR gain between rotation to the affected and unaffected sides at frequencies of 0.1-1.0 Hz. Although no differences in VOR gain at frequencies of 0.3-1.0 Hz were noticed in patients with apogeotropic positional nystagmus, the VOR gain at 0.1 Hz was significantly smaller on rotation to the affected compared to the unaffected side. CONCLUSION: The results indicate that cupulolithiasis in the HSCC affected the dynamics of the HSCC-ocular reflex at 0.1 Hz, but not at higher frequencies, and that canalolithiasis in the HSCC does not change the VOR gain of the HSCC at any frequency. It is suggested that cupulolithiasis causes transient impairment of HSCC function by means of its mechanical restriction of movements of the cupula.     

Purely vertical upbeat nystagmus in bilateral posterior canal benign paroxysmal positional vertigo: A case report

Vertical nystagmus occurs in patients with central vestibular system pathology. Lesions of the pons, medulla, and cerebellum lead to vertical nystagmus. Given this association, vertical nystagmus is considered pathognomonic in nature. We present a case of benign paroxysmal positional vertigo (BPPV) with positive Dix‐Hallpike bilaterally, but also with upbeat purely vertical nystagmus in the straight back head hanging position. Computed tomography imaging of the typically pathologic structures in vertical nystagmus (brainstem/posterior fossa) revealed normal anatomy. We propose this case as an instance of peripheral‐associated purely vertical nystagmus without central pathology, while building on our previous understanding of BPPV physiology. Laryngoscope, 2010     

Multiple positional nystagmus suggests multiple canal involvement in benign paroxysmal vertigo

CONCLUSION: Video-oculography demonstrates a higher occurrence of atypical positional nystagmus in patients with benign paroxysmal positional vertigo (BPPV). This includes anterior and horizontal canal variants and multiple positional nystagmus, suggesting combined lesions affecting several canals. OBJECTIVE: To analyse the video-oculographic findings of positional tests in patients with BPPV. MATERIAL AND METHODS: Seventy individuals with symptoms of BPPV and positional nystagmus were included in this study. The diagnosis was based on a history of brief episodes of vertigo and the presence of positional nystagmus as confirmed by video-oculographic examination during the Dix-Hallpike test, the McClure test or the head-hanging manoeuvre. Patients were treated by means of different particle repositioning manoeuvres according to the affected canal (Epley's manoeuvre for the posterior or anterior canals and Lempert's manoeuvre for the lateral canal) and the effectiveness was evaluated at 7 and 30 days. RESULTS: Twenty-nine individuals (41.43%) presented an affected unilateral posterior canal. Fifteen patients (21.43%) presented a pure horizontal direction-changing positional nystagmus consistent with a diagnosis of horizontal canal BPPV. Twelve individuals (17.14%) presented a unilateral down-beating nystagmus, suggesting possible anterior canal BPPV. In addition, 14 patients (20%) showed multiple positional nystagmus during the examination corresponding to simultaneous multi-canal BPPV, 5 had bilateral posterior canal BPPV and 2 presented a positional down-beating nystagmus in both left and right Dix-Hallpike manoeuvres and the head-hanging manoeuvre, which is highly suggestive of anterior canal BPPV. However, seven individuals showed positional horizontal and vertical side-changing nystagmus that could not be explained by single-canal BPPV. These patients with multiple positional nystagmus showed changing patterns of positional nystagmus at follow-up.     

Dynamics of the vestibulo-ocular reflex in patients with the horizontal semicircular canal variant of benign paroxysmal positional vertigo

Objective Two types of direction-changing positional nystagmus, the geotropic and apogeotropic variants, are observed in patients with the horizontal semicircular canal (HSCC) type of benign paroxysmal positional vertigo (H-BPPV). In this study, we assessed the dynamics of the vestibulo-ocular reflex (VOR) of the HSCC in patients with H-BPPV.

Material and Methods Patients were rotated about the earth-vertical axis at frequencies of 0.1, 0.3, 0.5, 0.7 and 1.0 Hz with a maximum angular velocity of 50°/s. Eye movements were recorded on a video imaging system using an infrared charge-coupled device (CCD) camera, and our new technique for analyzing the rotation vector of eye movements in three dimensions was used.

Results In the patients with geotropic positional nystagmus, there were no differences in VOR gain between rotation to the affected and unaffected sides at frequencies of 0.1–1.0 Hz. Although no differences in VOR gain at frequencies of 0.3–1.0 Hz were noticed in patients with apogeotropic positional nystagmus, the VOR gain at 0.1 Hz was significantly smaller on rotation to the affected compared to the unaffected side.

Conclusion The results indicate that cupulolithiasis in the HSCC affected the dynamics of the HSCC-ocular reflex at 0.1 Hz, but not at higher frequencies, and that canalolithiasis in the HSCC does not change the VOR gain of the HSCC at any frequency. It is suggested that cupulolithiasis causes transient impairment of HSCC function by means of its mechanical restriction of movements of the cupula.     

Differential diagnosis of true and pseudo-bilateral benign positional nystagmus

CONCLUSIONS: Two patients showing two rotational axes of their positional nystagmus had canalolithiasis in bilateral posterior semicircular canals (PSCCs), leading to the diagnosis of true bilateral benign paroxysmal positional nystagmus (P-BPPN). Another 18 patients had a single rotation axis of their positional nystagmus with short time constant (TC) on one side and long TC on the other. Since canalolithiasis in the uppermost PSCC may be transient cupulolithiasis, evoking positional nystagmus with long TC, the diagnosis of the latter patients should be pseudo-bilateral P-BPPN. OBJECTIVE: To differentiate the true bilateral posterior canal type of P-BPPN from pseudo-bilateral P-BPPN. PATIENTS AND METHODS: The rotational axis and TC of positional nystagmus were three-dimensionally analyzed in 20 patients showing geotropic torsional nystagmus on the left and right Dix-Hallpike (D-H) maneuvers. RESULTS: Two patients showed two rotational axes of their positional nystagmus, which were perpendicular to the plane of the PSCCs. There were no differences in TCs of their positional nystagmus between bilateral D-Hs. Another 18 patients showed a single rotational axis of their positional nystagmus, which was perpendicular to the plane of either the left or right PSCC. TCs of their positional nystagmus were short on one side and long on the other.     

Value of lying-down nystagmus in the lateralization of horizontal semicircular canal benign paroxysmal positional vertigo.

BACKGROUND: Horizontal canal benign paroxysmal positional vertigo is characterized by horizontal direction-changing nystagmus induced by lateral head turning in supine position. According to Ewald's second law, the direction of head turning that creates a stronger response represents the affected side in geotropic nystagmus and the healthy side in apogeotropic nystagmus. However, it may not always be possible to lateralize the involved ear only by comparing the intensity of the nystagmus. We studied the values of nystagmus induced by position change from sitting to supine in the lateralization of horizontal canal benign paroxysmal positional vertigo. METHODS: A retrospective study of 54 patients who had been diagnosed as having horizontal canal benign paroxysmal positional vertigo at the Dizziness Clinic of Seoul National University Bundang Hospital from May 2003 to February 2004 was performed. The directions of the nystagmus induced by lying down were compared with those determined by Ewald's second law. RESULTS: Of the 54 patients, 32 (20 apogeotropic and 12 geotropic) showed horizontal nystagmus induced by lying down. The nystagmus tended to be ipsilesional in apogeotropic patients (80%) and contralesional in their geotropic counterparts (75%). CONCLUSION: In horizontal canal benign paroxysmal positional vertigo, lying-down nystagmus mostly beats toward the involved ear in the apogeotropic type and directs to the healthy ear in the geotropic type. The direction of lying-down nystagmus may help lateralizing the involved ear in horizontal canal benign paroxysmal positional vertigo.     

水平半规管良性阵发性位置性眩晕的诊断

目的探讨水平半规管良性阵发性位置性眩晕（BPPV）的诊断。方法自2003年1月至2006年9月，本眩晕中心共确诊为水平半规管BPPV（HSC BPPV）患者46例。诊断依据为典型的病史及用红外视频眼震电图仪记录患者在Dix—Hallpike试验和滚转试验中的眼震结果，并排除其他疾病。研究HSC BPPV的眼震特点。结果441例诊断为BPPV患者中，46例（10．43％）为水平半规管BPPV。其中38例（82．61％）为单侧病变，5例（10．87％）患者合并同侧后半规管病变，3例（6．52％）为双侧病变。35例患者通过两种试验诱发出水平眼震，11例患者仅通过滚转试验诱发出水平眼震。25例患者眼震方向向地，13例患者眼震方向背地，3例患者眼震方向不固定，5例患者各种手法诱发出同一方向的眼震。29例患者在双侧手法中出现眼震，17例患者在一侧手法中出现眼震。结论HSC BPPV眼震为完全水平性且多为快相向地。通常受累耳在双侧手法中均可出现眼震，以向患侧为重。一侧水平半规管和后半规管可同时受累。滚转试验在HSC BPPV检查中比Dix—Hallpike试验更加敏感。Dix—Hallpike试验结合滚转试验可使更多的HSCBPPV患者得到确诊．     

Two types of direction-changing positional nystagmus with neutral points

Objectives

We encountered patients who had static direction-changing positional nystagmus (DCPN) canceled at about 20-30° yaw head rotation from the supine position. This nystagmus was also canceled when the head was rotated 180° from this position. We termed these head positions neutral points. The positional nystagmus observed (except at the neutral points) was thought to occur due to a “heavy cupula” or “light cupula”. The purpose of this study was to examine DCPN with neutral points as well as the pathomechanism of this condition.

Methods

Retrospective case review of patients attending two hospitals. Sixteen patients who exhibited DCPN with neutral points were examined using an infrared camera (installed in goggles). Using this system, the vestibulo-ocular reflex (VOR) was recorded, and VOR gain was obtained. Vestibular function and the affected side were determined. In addition, the angle between the supine position and neutral point was measured in each patient. We also examined other positional nystagmus occurring at other times.

Results

In the heavy cupula type group, we noted positional nystagmus for which repositioning maneuvers were successful, whereas, in the light cupula type group, repositioning maneuvers were not effective. The angle between supine position and neutral point was 26.5 ± 11.6°.

Conclusions

Heavy cupula type may occur as a result of otoconia while light cupula type may be due to the specific gravity of the endolymph. The VOR gain and side of the benign paroxysmal positional vertigo (BPPV) observed suggested that the affected side was that to which the neutral point was deviated.     

Benign paroxysmal positional vertigo due to a simultaneous involvement of both horizontal and posterior semicircular canals

From April 2001 to November 2003, we investigated 8 patients with benign paroxysmal positional vertigo (BPPV) that was suspected to simultaneously affect both the horizontal and posterior semicircular canals (HSCC and PSCC). These cases showed typical vertical-torsional nystagmus induced by the Dix-Hallpike maneuver, followed by a horizontal nystagmus. They also showed a direction-changing geotropic or apogeotropic positional nystagmus triggered by lateral head rotations in the supine position. Using the three-dimensional analysis of the positional nystagmus, the rotation axis of the positional nystagmus had a component perpendicular to the plane of PSCC and another component perpendicular to the plane of HSCC. All these findings suggest that BPPV in these patients was a combination of posterior and horizontal canal BPPV. The observation of a vertical-torsional positional nystagmus should prompt the specialist to perform not only the canalith repositioning procedure, but also to execute lateral head turns in the supine position.     

Multiple positional nystagmus suggests multiple canal involvement in benign paroxysmal positional vertigo

Conclusion. Video-oculography demonstrates a higher occurrence of atypical positional nystagmus in patients with benign paroxysmal positional vertigo (BPPV). This includes anterior and horizontal canal variants and multiple positional nystagmus, suggesting combined lesions affecting several canals. Objective. To analyse the video-oculographic findings of positional tests in patients with BPPV. Material and methods. Seventy individuals with symptoms of BPPV and positional nystagmus were included in this study. The diagnosis was based on a history of brief episodes of vertigo and the presence of positional nystagmus as confirmed by video-oculographic examination during the Dix–Hallpike test, the McClure test or the head-hanging manoeuvre. Patients were treated by means of different particle repositioning manoeuvres according to the affected canal (Epley's manoeuvre for the posterior or anterior canals and Lempert's manoeuvre for the lateral canal) and the effectiveness was evaluated at 7 and 30 days. Results. Twenty-nine individuals (41.43%) presented an affected unilateral posterior canal. Fifteen patients (21.43%) presented a pure horizontal direction-changing positional nystagmus consistent with a diagnosis of horizontal canal BPPV. Twelve individuals (17.14%) presented a unilateral down-beating nystagmus, suggesting possible anterior canal BPPV. In addition, 14 patients (20%) showed multiple positional nystagmus during the examination corresponding to simultaneous multi-canal BPPV, 5 had bilateral posterior canal BPPV and 2 presented a positional down-beating nystagmus in both left and right Dix–Hallpike manoeuvres and the head-hanging manoeuvre, which is highly suggestive of anterior canal BPPV. However, seven individuals showed positional horizontal and vertical side-changing nystagmus that could not be explained by single-canal BPPV. These patients with multiple positional nystagmus showed changing patterns of positional nystagmus at follow-up.     

继发性后半规管良性阵发性位置性眩晕的诊治

目的 探讨继发性良性阵发性位置性眩晕(BPPV)的诊断和治疗。方法研究继发性后半规管BPPV的内耳疾病6例病历资料,诊断依据为病史及Dix-Hallpike试验诱导出现的眼震结果。结果 6例内耳疾病(分别为突发性聋3例, 梅尼埃病2例, 前庭神经元炎1例)伴有后半规管良性阵发性位置性眩晕被确诊,通过Dix-Hallpike试验诱发出垂直扭转型眼震。结论 继发性BPPV临床较少见,常为后半规管受累,通过Dix-Hallpike试验和Epley手法复位可以确诊和治愈。     

Vertical canal function in normal subjects and patients with benign paroxysmal positional vertigo

OBJECTIVES: To assess the dynamics of the vertical semicircular canal (VSCC)-ocular reflex in normal subjects and then to compare their gain in VSCC-ocular reflex with that of patients with benign paroxysmal positional vertigo (BPPV). MATERIAL AND METHODS: Subjects were sinusoidally rotated around the earth-vertical axis with their head tilted 60 degrees backward and turned 45 degrees to the right or left side from the sagittal plane at frequencies of 0.1, 0.3, 0.5, 0.7 and 1.0 Hz with a maximum angular velocity of 50 degrees/s. Head rotation to the right side on the right anterior semicircular canal (SCC)-left posterior SCC plane or to the left side on the left anterior SCC-right posterior SCC plane stimulated the pair of VSCCs. Eye movements were recorded on a video imaging system with an infrared charge-coupled device camera, using our new technique for analyzing the rotation vector of eye movements in three dimensions. RESULTS: The mean gains in left posterior SCC-ocular reflex in normal subjects ranged from 0.44 at 0.1 Hz to 0.79 at 1.0 Hz, while the mean gains in right anterior SCC-ocular reflex ranged from 0.45 at 0.1 Hz to 0.73 at 1.0 Hz. The mean gains in right posterior SCC-ocular reflex in normal subjects ranged from 0.53 at 0.1 Hz to 0.89 at 1.0 Hz, while the mean gains in left anterior SCC-ocular reflex ranged from 0.53 at 0.1 Hz to 0.88 at 1.0 Hz. Thus, the gains in VSCC-ocular reflex did not differ among the four VSCCs in normal subjects. Similarly, vestibulo-ocular reflex (VOR) gains of the four VSCCs in patients with right- or left-sided BPPV were almost the same at all frequencies compared to those of normal subjects. CONCLUSION: In patients with BPPV, gains in VOR in the four VSCCs were not changed in comparison with those of normal subjects. It is suggested that the mass of free-floating otoconial debris associated with canalolithiasis was too small compared to that of the endolymph to change the canal dynamics.