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.     

Anterior semicircular canal benign paroxysmal positional vertigo and positional downbeating nystagmus

PURPOSE: The aim of this study was to describe the clinical features and video-oculographic findings in patients with anterior semicircular canal benign paroxysmal positional vertigo (BPPV). MATERIALS AND METHODS: STUDY DESIGN: This is a prospective case series. SETTING: The study was set at an outpatient clinic in a general hospital. PATIENTS: Fourteen individuals with symptoms of BPPV and positional downbeating nystagmus (pDBN) were included in the study. The diagnosis was based on a history of brief episodes of vertigo and the presence of pDBN confirmed in the video-oculographic examination during Dix-Hallpike test (DH) or head-hanging maneuver. INTERVENTION: Patients were treated by particle repositioning maneuver and the effectiveness was evaluated at 7, 30, and 180 days posttreatment. The treatment was repeated up to 4 times if pDBN was persistent. MAIN OUTCOME MEASURES: The main outcome measure is the number of patients without pDBN at 30 and 180 days. RESULTS: Video-oculography showed a predominant pDBN in response to DH. Of the 14 patients, 7 had arterial hypertension, and 5 of 14 cases presented abnormalities on the caloric test. Horizontal spontaneous nystagmus was found in 3 of 14 individuals. Positional nystagmus at different positional test was observed in 5 of 14 individuals, suggesting the involvement of several canals. Of the 14 patients, 10 (71%) did not present vertigo, and the positional tests were negative at 30 days. However, 3 cases presented a positive DH with persistence of BPPV episodes and pDBN at 30 days, and another developed a contralateral posterior canal affectation. One of the patients maintained a persistent pDBN at 180 days despite the repeated maneuvers. CONCLUSIONS: Video-oculography demonstrates that anterior canal BPPV is characterized by a predominant downbeating nystagmus in response to DH. These individuals may show alterations in the vestibular caloric, and they can have multicanal affectation.     

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．     

红外视频采集仪记录BPPV患者眼震的结果分析

目的探讨用红外视频眼动采集仪(CHARTR VNG)观察记录良性阵发性位置性眩晕(benign paroxys-mal positional vertigo,BPPV)患者的眼震特点。方法用红外视频采集仪详细记录78例BPPV患者在Dix-Hallpike试验及滚转试验中的眼震变化。结果40例(51.28%)为一侧后半规管病变;13例(16.67%)为一侧水平半规管病变;6例(7.7%)为一侧上半规管病变;19例(24.36%)出现多发位置性眼震,其中6例为双侧后半规管病变,2例双侧上半规管病变,3例为双侧水平半规管病变,8例患者在不同头位下出现眼震,提示混合半规管病变。结论红外视频眼动采集仪可以更直观地观察眼动变化,对诊断BPPV受累半规管提供可靠依据,特别是对非典型位置性的眼震,能更好的提示良性阵发性位置性眩晕患者非典型位置性的眼震发生率,包括水平半规管、上半规管病变和多个半规管联合病变。患者的治疗可以根据不同的受累半规管采取不同方法。     

上半规管良性阵发性位置性眩晕的诊断及治疗

目的探讨上半规管良性阵发性位置性眩晕（benign paroxysmal positional vertigo，BPPV）的诊断和治疗。方法回顾性分析了上半规管BPPV患者31例，并对所有患者采用管石复位法治疗后的效果进行评估。结果在Dix-Hallpike检查中，所有患者均诱发出垂直向下的眼震。22例（70．97％）患者一侧诱发出眼震，其中17例眼震伴有扭转成分，5例眼震不伴扭转成分。其余9例（29．03％）患者双侧诱发出现眼震，眼震伴有扭转成分的7例，其中2例眼震扭转方向指向同一侧，4例眼震的扭转方向不固定，1例患者仅一侧出现扭转成分。另外2例患者眼震不伴扭转成分。受累侧别明确诊断的19例（61．29％），其中11例为左侧上半规管受累，8例为右侧上半规管受累。受累侧别未明确诊断的12例（38．71％）。所有患者中，11例（35．48％）患者同时合并后半规管受累。对所有患者采取管石复位法治疗，21例（67．74％）痊愈，29例（93．55％）有效、2例（6．45％）无效。其中首次治愈14例（45．16％），平均治愈次数为1．71次。随访期间5例复发。结论上半规管BPPV临床中少见。在变位检查中，眼震的扭转成分较弱，临床中不易观察。在部分单侧上半规管BPPV患者中，双侧检查均能诱发眼震。管石复位法是治疗上半规管BPPV简单有效的手段。     

Benign paroxysmal positioning vertigo: diagnosis and therapy using video-oculographic control

In this prospective study, 82 patients (40 males, 42 females, aged between 15 and 80 years) with benign paroxysmal positioning vertigo (BPPV) were treated with different positioning manoeuvres using video-oculographic control. The maximum age for females and males was 31 and 40 years respectively. After an interview about the special history related to vertigo imbalance symptoms and using video-oculographic control, we diagnosed 79 patients with BPPV of the posterior semicircular canal and 3 of the horizontal semicircular canal. The Dix-Hallpike and Cawthorne manoeuvres were used for the diagnosis of BPPV of the posterior semicircular canal and the McClure manoeuvre for the diagnosis of BPPV of the horizontal semicircular canal. 72% of the patients had an idiopathic BPPV and 12.2% were post-traumatic. 3.7% had BPPV after ear surgery and 2.4% were pregnant. 39 patients with posterior BPPV were treated with Semont's manoeuvre and 40 with Epley's. The 3 patients with horizontal BPPV were treated with Baloh's manoeuvre. More than half of the patients (52.5%) were free of symptoms after one session of Epley's manoeuvre and all of them after four sessions. 51.3% had no further symptoms after one session of Semont's manoeuvre and all of them after four sessions. These results, in agreement with the literature, show that the success rate of Semont's and Epley's manoeuvres is approximately the same. Video-oculographic control is helpful for the diagnosis and for the registration of the eye movements during the therapeutic manoeuvres.     

Diagnosis and treatment of anterior canal benign paroxysmal positional vertigo

Abstract

Objective: To investigate the diagnosis and treatment of anterior canal benign paroxysmal positional vertigo (AC-BPPV).

Design: Retrospective analysis of clinical data regarding the diagnosis and treatment of patients with AC-BPPV.

Study sample: Six patients with AC-BPPV.

Results: All patients underwent the Dix–Hallpike test and/or the straight head-hanging test to induce vertigo and down-beating nystagmus with or without torsional components. Down-beating nystagmus in patients 1, 3 and 6 lasted <1?min and was successfully treated with the Yacovino manoeuvre. Down-beating nystagmus in patients 2, 4 and 5 lasted >1?min. The Yacovino manoeuvre was not effective in patient 4, whereas it was effective in patient 2 but with frequently recurring symptoms. Patients 3, 4 and 6 also had other types of typical BPPV. Canal conversion appeared in patients 4 and 5 during the follow-up period.

Conclusion: Typical BPPV, canal conversion, a therapeutic diagnosis after applying the Yacovino manoeuvre, and the follow-up outcome contribute to AC-BPPV diagnosis in patients with dizziness and vertigo presenting with down-beating positional nystagmus. Yacovino manoeuvre was more effective in AC-BPPV patients with down-beating positional nystagmus lasted <1?min than in those in whom it lasted >1?min.     

Benign paroxysmal positional vertigo of the horizontal and superior semicircular canals

The incidence of benign paroxysmal positional vertigo (BPPV) of the horizontal and superior semicircular canals is much less than that of BPPV due to affection of the posterior semicircular canal. Their diagnosis is however much more difficult and still prone to controversies. The provocative manoeuvre of the BPPV of the horizontal canal (BPPV-HSC) is the manoeuvre of rotation of the head in dorsal position. A horizontal positional nystagmus is obtained. There are two forms of BPPV-HSC: the geotropic form and the ageotropic form. In the geotropic form, the liberatory manoeuvre is a "barbecue" rotation of 180 with 360 degrees towards the healthy side. In the ageotropic form, there is no universal liberatory manoeuvre. Moreover as some cases of neurological aetiology have been recognized, it is not appropriate to apply ineffective manoeuvres. The BPPV of the superior canal (BPV-SSC) is very rare. The provocative manoeuvre is the Dix and Hallpike's manoeuvre. It causes positional torsional and vertical nystagmus with an opposite direction to that obtained for a BPPV of the contra-lateral posterior canal. The liberatory manoeuvre is a Semont manoeuvre, which is identical to that we would make for a contra-lateral BPPV of the posterior canal.     

The test and treatment methods of benign paroxysmal positional vertigo and an addition to the management of vertigo due to the superior vestibular canal (BPPV‐SC)

A review of the tests and treatment manoeuvres for benign paroxysmal positional vertigo of the posterior, horizontal and superior vestibular canals is presented. Additionally, a new way to test and treat positional vertigo of the superior vestibular canal is presented. In a prospective study, 57 out of 305 patients' visits are reported. They had residual symptoms and dizziness after the test and the treatment of benign paroxysmal positional vertigo of the horizontal canal (BPPV‐HC) and posterior canal (PC). They were tested with a new test and treated with a new manoeuvre for superior canal benign paroxysmal positional vertigo (BPPV‐SC). Results for vertigo in 53 patients were good; motion sickness and acrophobia disappeared. Reactive neck tension to BPPV was relieved. Older people were numerous among patients and their quality of life (QOL) improved.     

Persistent positional nystagmus

Involvement of the superior semicircular canal (SSC) in benign paroxysmal positional vertigo (BPPV) is rare. SSC BPPV is distinguished from the more common posterior semicircular canal (PSC) variant by the pattern of nystagmus triggered by the Dix-Hallpike position: down-beating torsional nystagmus in SSC BPPV versus up-beating torsional nystagmus in PSC BPPV. SSC BPPV may be readily treated at the bedside, which is a key component in excluding central causes of down-beating nystagmus. We present an unusual video case report believed to represent refractory SSC BPPV based on the pattern of nystagmus and the absence of any other central signs.     

Prospective study of positional nystagmus in 100 consecutive patients

OBJECTIVES: The purpose of this study was to investigate the various diagnoses of patients who present with positional nystagmus. METHODS: Positional maneuvers were systematically performed in the plane of the posterior canal (PC; Dix-Hallpike maneuver) and the horizontal canal (HC; patients were rolled to either side in a supine position) on 490 consecutive patients essentially referred for vertigo and/or gait unsteadiness. RESULTS: One hundred patients (20%) presented positional nystagmus. This nystagmus had a peripheral origin in 83 patients, including 80 patients with benign paroxysmal positional vertigo (BPPV). In BPPV, the PC was involved in 61 patients, the HC in 18 patients (geotropic horizontal nystagmus in 11 and ageotropic in 7; changing from geotropic to ageotropic or the reverse in 4 patients), and both the PC and HC in 1 patient. There was evidence of central positional nystagmus in 12 patients, including positional downbeat nystagmus during the Dix-Hallpike maneuver in 7 patients with various neurologic disorders, and ageotropic horizontal nystagmus during the HC maneuver in 2 patients with, respectively, cerebellar ischemia and definite migrainous vertigo. The peripheral or central origin of the positional nystagmus could not be ascertained in 5 patients, including 1 patient with probable migrainous vertigo and another with possible anterior canal BPPV. CONCLUSIONS: A rotatory-upbeat nystagmus in the context of PC BPPV, a horizontal nystagmus, whether geotropic or ageotropic, due to HC BPPV, and a positional downbeat nystagmus related to various central disorders are the 3 most common types of positional nystagmus. Geotropic horizontal positional nystagmus and, most certainly, horizontal positional nystagmus changing from geotropic to ageotropic or the reverse point to HC BPPV. In contrast, an ageotropic horizontal positional nystagmus that is not changing (from ageotropic to geotropic) may indicate a central lesion.     

Practical approach to recurrent benign paroxysmal positional vertigo

Benign paroxysmal positional vertigo is the most common vestibular disorder and it has a significant impact on health-related quality of life. The disease is probably caused by the accumulation of lithiasis material from the otolithic membrane of the utricle. Patients experience multiple short vertigo crises lasting seconds when they go to bed or turn over. There are several clinical variants affecting posterior, horizontal or anterior canals and in some cases vestibular lithiasis can occur in two canals simultaneously. Diagnosis is by video-oculographic recording of positional nystagmus during positional tests to identify the canal affected. There are specific treatment manoeuvres for each clinical variant, which a high degree of short-term effectiveness.     

The test and treatment methods of benign paroxysmal positional vertigo and an addition to the management of vertigo due to the superior vestibular canal (BPPV-SC)

A review of the tests and treatment manoeuvres for benign paroxysmal positional vertigo of the posterior, horizontal and superior vestibular canals is presented. Additionally, a new way to test and treat positional vertigo of the superior vestibular canal is presented. In a prospective study, 57 out of 305 patients' visits are reported. They had residual symptoms and dizziness after the test and the treatment of benign paroxysmal positional vertigo of the horizontal canal (BPPV-HC) and posterior canal (PC). They were tested with a new test and treated with a new manoeuvre for superior canal benign paroxysmal positional vertigo (BPPV-SC). Results for vertigo in 53 patients were good; motion sickness and acrophobia disappeared. Reactive neck tension to BPPV was relieved. Older people were numerous among patients and their quality of life (QOL) improved.     

“Sitting-up vertigo as an expression of posterior semicircular canal heavy cupula and posterior semicircular canal short arm canalolithiasis”

BackgroundVestibular symptoms on sitting-up are frequent on patients seen by vestibular specialists. Recently, a benign paroxysmal positional vertigo (BPPV) variant which elicits vestibular symptoms with oculomotor evidence of posterior semicircular canal (P-SCC) cupula stimulation on sitting-up was described and named sitting-up vertigo BPPV. A periampullar restricted P-SCC canalolithiasis was proposed as a causal mechanism.ObjectiveTo describe new mechanisms of action for the sitting-up vertigo BPPV variant.MethodsEighteen patients with sitting-up vertigo BPPV were examined with a pre-established set of positional maneuvers and follow-up until they resolved their symptoms and clinical findings.ResultsAll patients showed up-beating torsional nystagmus (UBTN) and vestibular symptoms on coming up from either Dix-Hallpike (DHM) or straight head-hanging maneuver. Sixteen out of 18 patients presented a sustained UBTN with an ipsitorsional component to the tested side on half-Hallpike maneuver (HH). A slower persistent contratorsional down-beating nystagmus was found in eleven out 18 patients tested on nose down position (ND).ConclusionsPersistent direction changing positional nystagmus on HH and ND positions indicative of P-SCC heavy cupula was found in 11 patients. A sustained UBTN on HH with the absence of findings on ND, which is suggestive of the presence of P-SCC short arm canalolithiasis, was found on 5 patients. All patients were treated with canalith repositioning maneuvers without success, but they resolved their findings by means of Brandt-Daroff exercises. We propose P-SCC heavy cupula and P-SCC short arm canalolithiasis as two new putative mechanisms for the sitting-up vertigo BPPV variant.     

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.     

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.     

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.     

Treatment of anterior benign paroxysmal positional vertigo by canal plugging: a case report

A 75-year-old man with incapacitating anterior canal benign paroxysmal positional vertigo (BPPV) was relieved of symptoms following anterior semicircular canal occlusion using a transmastoid approach. The preoperative symptoms were similar to those of posterior canal BPPV. The preoperative findings on Dix-Hallpike's maneuver were a paroxysmal torsional nystagmus with a down-beating component that increased when the patient's gaze was directed towards the affected ear. The most provoking head movement for the vertigo/nystagmus was Dix-Hallpike's maneuver with the affected ear lowermost.     

Combined horizontal and posterior canal benign paroxysmal positional vertigo in three patients with head trauma

We report 3 patients who complained of positional vertigo shortly after head trauma. Positional maneuvers performed in the plane of the posterior canal (PC; Dix-Hallpike maneuver) and the horizontal canal (HC; patients were rolled to either side in a supine position with the head raised 30 degrees) revealed a complex positional nystagmus that could only be interpreted as the result of combined PC and HC benign paroxysmal positional vertigo (BPPV). Two patients had a right PC BPPV and an ageotropic HC BPPV, and 1 patient had a bilateral PC BPPV and a left geotropic HC BPPV. All 3 patients were rapidly free of vertigo after the PC BPPV was cured by the Epley maneuver and the geotropic HC BPPV was cured by the Vannucchi method. The ageotropic HC BPPV resolved spontaneously. Neuroimaging (brain computed tomography and/or magnetic resonance imaging scans) findings were normal in all 3 patients. From a physiopathological viewpoint, it is easy to conceive that head trauma could throw otoconial debris into different canals of each labyrinth and be responsible for these combined forms of BPPV. Consequently, in trauma patients with vertigo, it is mandatory to perform the Dix-Hallpike maneuver, as well as supine lateral head turns, in order to diagnose PC BPPV, HC BPPV, or the association of both. Early diagnosis and treatment of BPPV may help to reduce the postconcussion syndrome.     

Positional and positioning down-beating nystagmus without central nervous system findings

We report the clinical features of 4 cases with positional or positioning down-beating nystagmus in a head-hanging or supine position without any obvious central nervous system disorder. The 4 cases had some findings in common. There were no abnormal findings on neurological tests or brain MRI. They did not have gaze nystagmus. Their nystagmus was observed only in a supine or head-hanging position and it was never observed upon returning to a sitting position and never reversed. The nystagmus had no or little torsional component, had latency and tended to decrease with time. The positional DBN (p-DBN) is known to be indicative of a central nervous system disorder. Recently there were some reports that canalithiasis of the anterior semicircular canal (ASC) causes p-DBN and that patients who have p-DBN without obvious CNS dysfunction are dealt with anterior semicircular canal (ASC) benign paroxysmal positional vertigo (BPPV). There are some doubts as to the validity of making a diagnosis of ASC-BPPV in a case of p-DBN without CNS findings. It is hard to determine the cause of p-DBN in these cases.