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.     

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．     

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.     

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.     

Benign paroxysmal positional vertigo

Benign paroxysmal positional vertigo (BPPV) is characterized by positional vertigo (brief attacks of rotatory vertigo triggered by head position changes in the direction of gravity) and is the most common peripheral cause of vertigo. There are two types of BPPV pathophysiology: canalolithiasis and cupulolithiasis. In canalolithiasis, otoconial debris is detached from the otolithic membrane and floats freely within the endolymph of the canal. In cupulolithiasis, the otoconial debris released from the otolithic membrane settles on the cupula of the semicircular canal and the specific gravity of the cupula is increased. Consensus has been reached regarding three subtypes of BPPV: posterior-canal-type BPPV (canalolithiasis), lateral-canal-type BPPV (canalolithiasis) and lateral-canal-type BPPV (cupulolithiasis). In the interview-based medical examination of BPPV, questions regarding the characteristics of vertigo, triggered movement of vertigo, duration of vertigo and cochlear symptoms during vertigo attacks are important for the diagnosis of BPPV. The Dix–Hallpike test is a positioning nystagmus test used for diagnosis of posterior-canal-type BPPV. The head roll test is a positional nystagmus test used for diagnosis of lateral-canal-type BPPV. When the Dix–Hallpike test is repeated, positional nystagmus and the feeling of vertigo typically become weaker. This phenomenon is called BPPV fatigue. The effect of BPPV fatigue typically disappears within 30 min, at which point the Dix–Hallpike test again induces clear positional nystagmus even though BPPV fatigue had previously caused the positional nystagmus to disappear. For the treatment of BPPV, sequential head movements of patients can cause the otoconial debris in the semicircular canal to move to the utricle. This series of head movements is called the canalith repositioning procedure (CRP). The appropriate type of CRP depends on the semicircular canal in which the otoconial debris is located. The CRP for posterior-canal-type BPPV is called the Epley maneuver, and the CRP for lateral-canal-type BPPV is called the Gufoni maneuver. Including a time interval between each head position in the Epley maneuver reduces the immediate effect of the maneuver. This finding can inform the development of methods for reducing the effort exerted by doctors and the discomfort experienced by patients with posterior-canal-type BPPV during the Epley maneuver.     

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.     

Dynamics of canal response to head-shaking test in benign paroxysmal positional vertigo

CONCLUSIONS: Time constant and maximum slow phase velocity (SPV) of head-shaking nystagmus (HSN) demonstrated a differential canal response to head shaking in 24% of patients with posterior canal benign paroxysmal positional vertigo (BPPV). We suggest that vestibular lithiasis has a limited contribution to the mechanism that generates HSN. OBJECTIVE: To determine the canal response to head shaking in BPPV. PATIENTS AND METHODS: This was a case-control study including 104 individuals with BPPV. The diagnosis was based on the presence of vertigo and nystagmus during the positional test. Subjects were examined by the horizontal and vertical head-shaking test. Eye movements were recorded on a video camera to analyze the nystagmus. The head was shaken passively in the horizontal and sagittal planes, respectively, for horizontal and vertical HSN at a frequency of 2 Hz. HSN was considered when six consecutive beats of nystagmus with an SPV of at least 2 degrees/s were detected. Main outcome measures were the presence of horizontal and vertical HSN, maximum SPV of HSN, time constant of HSN, and canal paresis. RESULTS: Maximum SPV of vertical HSN was higher in BPPV patients with posterior canal BPPV (n = 10) than in controls (p = 0.04). Moreover, the time constant of vertical HSN was significantly lower for posterior canal BPPV when compared with controls (p < 0.02).     

Benign paroxysmal positional vertigo showing sequential translations of four types of nystagmus

Objective

We report a case of benign paroxysmal positional vertigo (BPPV) showing sequential translation of four types of nystagmus and discuss its pathophysiology.

Methods

The case was 65-year-old female. We analyzed her nystagmus three-dimensionally.

Results

At the first visit, she showed vertical-torsio nystagmus of the posterior canal type of BPPV (P-BPPV) and subsequently showed recently reported geotropic nystagmus with a long time constant. Two weeks later, she showed apogeotropic nystagmus of the horizontal canal type of BPPV (AH-BPPV) and subsequently a geotropic nystagmus with a short time constant of the horizontal canal type of BPPV (GH-BPPV).

Conclusions

Three kind of nystagmus, namely P-BPPV, AH-BPPV and GH-BPPV can be explained by the otoconial debris hypothesis of the same ear. Finally, the recently reported geotropic nystagmus with a long time constant may be explained by a reversible lesion such as the denatured cupula or utricular imbalance of the same ear.     

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.     

Dynamics of canal response to head-shaking test in benign paroxysmal positional vertigo

Conclusions. Time constant and maximum slow phase velocity (SPV) of head-shaking nystagmus (HSN) demonstrated a differential canal response to head shaking in 24% of patients with posterior canal benign paroxysmal positional vertigo (BPPV). We suggest that vestibular lithiasis has a limited contribution to the mechanism that generates HSN. Objective. To determine the canal response to head shaking in BPPV. Patients and methods. This was a case-control study including 104 individuals with BPPV. The diagnosis was based on the presence of vertigo and nystagmus during the positional test. Subjects were examined by the horizontal and vertical head-shaking test. Eye movements were recorded on a video camera to analyze the nystagmus. The head was shaken passively in the horizontal and sagittal planes, respectively, for horizontal and vertical HSN at a frequency of 2 Hz. HSN was considered when six consecutive beats of nystagmus with an SPV of at least 2°/s were detected. Main outcome measures were the presence of horizontal and vertical HSN, maximum SPV of HSN, time constant of HSN, and canal paresis. Results. Maximum SPV of vertical HSN was higher in BPPV patients with posterior canal BPPV (n=10) than in controls (p=0.04). Moreover, the time constant of vertical HSN was significantly lower for posterior canal BPPV when compared with controls (p<0.02).     

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.     

Horizontal canal type BPPV: bilaterally affected case treated with canal plugging and Lempert's maneuver

A 54-year-old woman complained of positional vertigo. During 3 months' observation, the patient showed mostly geotropic or apogeotropic nystagmus due to right canalolithiasis or cupulolithiasis, however, she sometimes showed nystagmus which suggested left horizontal canalolithiasis. We suspected that she suffered from bilateral horizontal canal type benign paroxysmal positional vertigo (BPPV) and performed Lempert's maneuver for both directions, however, they were ineffective. She underwent canal plugging for right horizontal canal. After surgery she showed no positional nystagmus of right horizontal canal origin. However, apogeotropic nystagmus of the left horizontal canal origin was still observed. This nystagmus changed to geotropic nystagmus and finally disappeared following Lempert's maneuver for the left side. Bilateral horizontal canal BPPV is difficult to be resolved, probably because physical treatment for one side would move debris to the cupula in the other canal. Canal plugging combined with Lempert's maneuver to the other side is one treatment option for intractable bilateral horizontal canal BPPV.     

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.     

Anterior canal benign paroxysmal positional vertigo: an underappreciated entity.

OBJECTIVE: Evaluate the frequency and characteristics of benign paroxysmal positional vertigo (BPPV) arising from involvement of the anterior semicircular canal (AC) as compared with the posterior canal (PC) and horizontal canal (HC). STUDY DESIGN: Prospective review of patients with BPPV. SETTING: Tertiary referral center. PATIENTS: A total of 260 patients who were evaluated for vertigo were identified as experiencing BPPV. INTERVENTIONS: Standard vestibular assessment including the use of electrooculography (EOG) or video-oculography (VOG) was completed on all patients. Based on EOG/VOG findings, the BPPV origin was attributed to AC, PC, or HC involvement secondary to canalithiasis versus cupulolithiasis. Treatment was performed with canalith repositioning maneuvers (CRMs) appropriate for type of canal involvement. RESULTS: For the 260 patients, the positionally induced nystagmus patterns suggested the canal of origin to be AC in 21.2%, PC in 66.9%, and HC in 11.9%. Cupulolithiasis was observed in 27.3% of the AC, 6.3% of the PC, and 41.9% of the HC patients. Head trauma was confirmed in the history preceding the onset of vertigo in 36.4% of the AC, versus 9.2% of the PC and 9.7% of the HC patients (p < 0.001). The number of CRMs completed to treat the BPPV did not differ between canals involved (1.32 for AC, 1.49 for PC, and 1.34 for HC). CONCLUSION: The direction of subtle vertical-beating nystagmus underlying the torsional component is critical in differentiating AC versus PC origin; EOG/VOG aids in accurate assessment of the vertical component for the diagnosis of canal involvement. AC involvement may be more prevalent than previously appreciated, particularly if the examiner does not appreciate the vertical component of the nystagmus or the diagnosis is made without the assistance of EOG/VOG. Head trauma history is significantly more frequent in AC versus other forms of BPPV, and patients with a history of head trauma should be examined closely for AC involvement. CRM is as successful for treatment of AC BPPV as for other types of BPPV.     

Persistent Direction-Fixed Nystagmus Following Canalith Repositioning Maneuver for Horizontal Canal BPPV: A Case of Canalith Jam

The authors report a 64-year-old man who developed persistent direction fixed nystagmus after a canalith repositioning maneuver for horizontal canal benign paroxysmal positional vertigo (HC-BPPV). The patient was initially diagnosed with right HC-BPPV given that the Dix-Hallpike test showed geotropic horizontal nystagmus that was more pronounced on the right side, although the roll test did not show any positional nystagmus. The patient was treated with a canalith repositioning maneuver (Lempert maneuver). The next day, the patient experienced a different character of dizziness, and left-beating spontaneous nystagmus regardless of head position was observed. After a forced prolonged left decubitus and frequent head shaking, his symptoms and nystagmus resolved. This condition, referred to as canalith jam, can be a complication after the repositioning maneuver in patients with BPPV. Atypical positional tests suggest that abnormal canal anatomy could be the underlying cause of canalith jam.     

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.     

正中悬头位Dix-Hallpike法诊断良性阵发性位置性眩晕

目的评价正中悬头位Dix-Hallpike诱发检查法在诊断后半规管良性阵发性位置性眩晕(benign paroxysmal positional vertigo,BPPV)中的意义。方法回顾性总结广东省人民医院耳鼻咽喉科眩晕门诊2008年4月1日到5月29日根据经典或者正中悬头位Dix-Hallpike法诊断为后半规管BPPV患者28例的临床资料,均首先进行正中悬头位Dix-Hallpike诱发试验,如结果为阴性后继续行经典Dix-Hallpike检测证实为后半规管性BPPV。比较正中悬头位Dix-Hallpike相对于经典Dix-Hallpike的阳性率。结果28例后半规管BPPV患者中,正中悬头位Dix-Hallpike诱发试验相对于经典Dix-Hallpike诱发实验的阳性率为78.57%(22/28)。结论正中悬头位Dix-Hallpike法诊断BPPV可以有效地简化诊治程序,并减轻部分患者诱发的眩晕及眼震强度,具有一定的临床意义。但由于其阳性率低于经典方法,故在临床上不能完全代替经典方法。     

3D analysis of benign positional nystagmus due to cupulolithiasis in posterior semicircular canal

Conclusions: The characteristic of both the vertical-torsional positional nystagmus with long time constant and its disappearance at the neutral head position could diagnose cupulolithiasis in posterior semicircular canal (PSCC) in the eight patients with the PSCC type of benign paroxysmal positional vertigo (P-BPPV). Objective: The aim of the study was to diagnose cupulolithiasis in patients with P-BPPV. Patients and methods: We used three-dimensional rotation axis analysis of nystagmus of the vertical-torsional positional nystagmus in 111 patients with P-BPPV and evaluated its time constant. We then examined whether the vertical-torsional positional nystagmus with long time constant disappeared at the neutral head position where the axis of the heavy cupula of the affected PSCC is aligned with gravity. Results: The first parameter showed a wide variation that could be divided into two groups: one lasting more than 40 s in 8 patients and another below 20 s in 103 patients. Since the time constant of the positional nystagmus induced by cupulolithiasis was much longer than that induced by canalolithiasis, this finding suggests that cupulolithiasis in the PSCC induced the vertical-torsional positional nystagmus with a long time constant in the group of eight patients. The vertical-torsional positional nystagmus disappeared in these patients at the neutral head position, where the axis of the cupula of affected PSCC aligned with gravity.     

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。     

后半规管良性阵发性位置性眩晕患者复位中眼震分析

目的 分析后半规管良性阵发性位置性眩晕(posterior semicircular canal benign paroxysmal positional vertigo,PC-BPPV)患者复位中的眼震,探讨BPPV可能的发病机制.方法 2007年12月至2008年4月眩晕门诊就诊的66例PC-BPPV患者,详细记录病史、体位试验及复位中不同位置眼震的情况,对PC-BPPV患者可能发病机制进行探讨.结果 变位试验完伞符合贵阳会议诊断标准的66例PC-BPPV患者,采用改良Epley复位,视频眼震记录技术记录复位中四个位置的眼震方向及强度,24例患者复位中出现的眼震均为垂直扭转向上眼震;21例除第一个位置出现上向扭转眼震,其余三个位置眼震阴性;7例变位试验初诊PC-BPPV的患者在第二次复位中出现强烈水平眼震;14例患者复位的第二或第三个位置出现下向垂直眼震.由复位中不同位置出现的眼震分析,66例确诊为PC-BPPV的患者,52例复位中的表现符合管石及嵴顶耳石症理论,占78.8%.结论 除了目前公认的管石症及嵴顶耳石症理论外,推测部分PC-BPPV可能与耳石器官及球囊椭圆囊神经病变有关.