Three-dimensional eye rotation axis analysis of benign paroxysmal positioning nystagmus

We have developed a new technique for analyzing the rotation vector of eye movement with an infrared CCD camera [Imai et al.: Acta Otolaryngol 1999;119:24-28]. We used this technique to analyze the eye rotation axis of benign paroxysmal positioning nystagmus (BPPN) that was induced by the Dix-Hallpike maneuver in 14 patients with benign paroxysmal positioning vertigo (BPPV). Eye rotation axes of BPPN in 8 patients were closely perpendicular to the posterior canal of the undermost ear in the provocative head position. Under the hypothesis that BPPN is due to a mechanical stimulation of the posterior canal by canalolithiasis, this finding suggested that the posterior canal of the undermost ear is the lesion. On the other hand, eye rotation axes of BPPN in the other 6 patients were closely aligned with the naso-occipital axis. It is suggested that canalolithiasis induces endolymphatic flow in both posterior and anterior canals via the common crus and the summation of the eye movements induced by stimulation of both the posterior and anterior canals rotates the eye along the naso-occipital axis.     

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.     

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。     

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.     

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.     

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     

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.     

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.     

A novel maneuver for diagnosis and treatment of torsional-vertical down beating positioning nystagmus: anterior canal and apogeotropic posterior canal BPPV

IntroductionIn patients with benign paroxysmal positional vertigo, BPPV; a torsional-vertical down beating positioning nystagmus can be elicited in the supine straight head-hanging position test or in the Dix-Hallpike test to either side. This type of nystagmus can be explained by either an anterior canal BPPV or by an apogeotropic variant of the contralateral posterior canal BPPV Until now all the therapeutic maneuvers that have been proposed address only one possibility, and without first performing a clear differential diagnosis between them.ObjectiveTo propose a new maneuver for torsional-vertical down beating positioning nystagmus with a clear lateralization that takes into account both possible diagnoses (anterior canal-BPPV and posterior canal-BPPV).MethodsA prospective cohort study was conducted on 157 consecutive patients with BPPV. The new maneuver was performed only in those with torsional-vertical down beating positioning nystagmus with clear lateralization.ResultsTwenty patients (12.7%) were diagnosed with a torsional-vertical down beating positioning nystagmus. The maneuver was performed in 10 (6.35%) patients, in whom the affected side was clearly determined. Seven (4.45%) patients were diagnosed with an anterior canal-BPPV and successfully treated. Two (1.25%) patients were diagnosed with a posterior canal-BPPV and successfully treated with an Epley maneuver after its conversion into a geotropic posterior BPPV.ConclusionThis new maneuver was found to be effective in resolving all the cases of torsional-vertical down beating positioning nystagmus-BPPV caused by an anterior canal-BPPV, and in shifting in a controlled way the posterior canal-BPPV cases of the contralateral side into a geotropic-posterior-BPPV successfully treated during the followup visit. Moreover, this new maneuver helped in the differential diagnosis between anterior canal-BPPV and a contralateral posterior canal-BPPV.     

Spontaneous nystagmus in benign paroxysmal positional vertigo

Objective

The purpose of this study was to evaluate the presence and eventually to study the features of spontaneous nystagmus (Ny) in our patients with diagnosis of benign paroxysmal positional vertigo (BPPV).

Patients and methods

We retrospectively reviewed the clinical records of patients who presented with vertigo spells and were managed at our tertiary care referral center. Patients with only idiopathic BPPV presenting with typical vertigo spells and positioning Ny characteristic of the disease were included in this study. To investigate the positioning Ny, we studied the patients in the sitting position, during the head shaking test, and during the Dix-Hallpike test and the McClure-Pagnini test (Ny provoked by rotation of the head in a supine patient). Ny responses in all patients were observed using infrared videoscopy.

Results

We managed 412 patients affected by BPPV. Of the 412 patients, 292 (70.87%) were diagnosed to be having posterior canal-BPPV and 110 (26.99%) patients had horizontal canal-BPPV (HC-BPPV). The remaining 10 patients (2.44%) were identified to have anterior canal-BPPV. Spontaneous Ny in sitting position was observed, by infrared videoscopy, only in the patients affected by HC-BPPV.

Conclusion

Spontaneous Ny in BPPV can be observed with infrared videoscopy in patients affected by HC-BPPV. The origin of this Ny is most likely due to a natural inclination of horizontal semicircular canal with respect to the horizontal plane. This Ny stops after flexion of the head in neutral position, and for this reason, it should be considered as a seemingly spontaneous Ny. This Ny, in our experience, is observed in most HC-BPPV patients but does not indicate the need for a different management protocol or any different prognostic value of HC-BPPV.     

A case of apogeotropic nystagmus with brainstem lesion: An implication for mechanism of central apogeotropic nystagmus

We report a case showing apogeotropic nystagmus with the lesion of the brain stem, and discuss a possible mechanism of central apogeotropic nystagmus. The case was a 73-year-old male. We analyzed his nystagmus three-dimensionally. He showed apogeotropic nystagmus. Axis angles of slow phase eye velocity of his apogeotropic nystagmus were not in line with the axes perpendicular to the plane of horizontal semicircular canals, but with the patient's vertical axis. We then found that his nystagmus including the apogeotropic nystagmus was positioning, but not positional and that the direction of his positioning nystagmus was the same direction of postrotatory nystagmus after his head movement. His MRI scans showed an infarction around the prepositus hypoglossi nucleus of the brain. His apogeotropic nystagmus seemed to consist of a combination of prolonged postrotatory nystagmus after his head rotation to the left and right lateral position because the axis of postrotatory nystamus was in line with the axis of the head rotation. Therefore, it is suggested that a possible mechanism of central apogeotropic nystagmus is a prolonged postrotatory nystagmus after his head movement in the supine position due to the brain lesion involving the velocity storage mechanisms.     

3D analysis of spontaneous nystagmus in early stage of vestibular neuritis

Objective

The pathological localization of vestibular neuritis is still controversial. Analyses of the spontaneous nystagmus support the temporal bone studies, which indicated the location of the pathology to be in the superior vestibular nerve. However, based on the data from the head impulse testing the pathology is in the vestibular nerve including the inferior branch.

Methods

Twenty-three patients with vestibular neuritis participated in this study. The spontaneous nystagmus was recorded within 1 week after the onset of the disease. Three-dimensional analysis of the nystagmus was performed using video image analysis system. The rotation axis was calculated and compared to the anatomical axes of the semicircular canals.

Results

The axes of the spontaneous nystagmus in all patients were scattered around the axes of horizontal and anterior canals, especially between the compound axis of anterior and horizontal canals and the axis of horizontal canal. The statistical analysis revealed that in the quite early stage of the disease (day 0–2 of the attack), the spontaneous nystagmus tended to have more torsional eye movements as compared to the less early stage (day 3–6).

Conclusion

The present study strongly suggests that the pathology of vestibular neuritis is in the superior vestibular nerve branch. Also it can be speculated that at the early stage of this disease, the pathology is in the whole branch of the nerve. Subsequently, the anterior canal branch recovers faster than the horizontal canal branch.     

Clinical features of benign paroxysmal positional vertigo

Our understanding of the pathomechanism of benign paroxysmal positional vertigo (BPPV) has improved dramatically. A type of BPPV featuring mixed torsional and vertical nystagmus induced by the Dix-Hallpike maneuver involves the posterior semicircular canal (P-BPPV). The other type of BPPV featuring horizontal nystagmus induced by spine-to-lateral head positioning involves the horizontal canal BPPV (H-BPPV). In complaints of vertigo or dizziness, 619 patients visited our department last year. Of these, 142 (23%) was had positional nystagmus consistent with a diagnosis of BPPV, 118 (19%) had no nystagmus but were suspected of BPPV due to vertigo episodes. BPPV was the most frequent diagnosis. H-BPPV was not rare, but accounted for 30% of BPPV. Of H-BPPV, 73% featured direction changing geotropic nystagmus, and 27% direction changing apogeotropic nystagmus. H-BPPV resolved faster than P-BPPV. Most cases caused by head trauma were P-BPPV. Transition between P- and H-BPPV was found in 6 cases. Women outnumbered men by about 3 to 2 in both P- and H-BPPV. Peak incidence was found in the those in their 60s and 70s, suggesting that the etiologies of both types of BPPV are essentially the same.     

Approach to bilateral benign paroxysmal positioning vertigo

BACKGROUND: Bilateral benign paroxysmal positioning vertigo (bBPPV) is rather rare, accounting for up to 10% in the reported benign paroxysmal positioning vertigo (BPPV) series. Inappropriate head positioning during testing in unilateral BPPV causes the otolith debris in the uppermost ear to move toward the cupula, resulting in an inhibitory nystagmus and mimicking bBPPV. PURPOSE: We analyzed the clinical data of patients with bilaterally positive Dix-Hallpike maneuver and compared them with the characteristics of patients with unilateral BPPV. We further tried to propose a simple schematic approach to the treatment of patients with bilaterally positive Dix-Hallpike maneuver. MATERIALS AND METHODS: Medical records of 232 patients treated for BPPV at our dizziness clinic during 1999 to 2003 were reviewed. An algorithm used for the treatment of patients with bilaterally positive BPPV is discussed. RESULTS: Twenty-eight patients with bilaterally positive Dix-Hallpike test were found. Sixteen were diagnosed with bBPPV, and 12 were diagnosed with unilateral mimicking bBPPV. Thirty patients with unilateral posterior canal BPPV served as control subjects. No difference in age, sex distribution, duration of symptoms, number of treatments per ear, and recurrence was found between bBPPV and unilateral BPPV. The female sex appeared to be predisposed for more treatments. The total duration of BPPV symptoms obtained by history was found to correlate with the number of recurrences after treatment. CONCLUSIONS: We conclude that bBPPV can be readily distinguished from unilateral mimicking bBPPV. Patients with bBPPV do not differ from patients with unilateral BPPV in clinical characteristics. The mechanism of otolith debris dislodgment appears to be the main cause of bilaterality, trauma being a more common trigger than other known causes of BPPV.     

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.     

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.     

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.     

318例良性阵发性位置性眩晕的诊治分析

目的:研究不同类型良性阵发性位置性眩晕(BPPV)的诊断、治疗及疗效。方法:回顾性分析318例BPPV患者的资料,根据变位试验诱发的眼震特点进行分型,并采用相应的耳石复位技术治疗,对治疗1次无效者间隔7d重复治疗,重复3次无效者采用Brandt-Daroff习服练习;完成治疗后随访观察总有效率。结果:①后半规管BPPV患者221例(69.5%),采用Epley管石复位法;②水平半规管BPPV患者62例(19.5%),采用Bar-becue翻滚加强迫侧卧体位疗法;③前半规管BPPV患者23例(7.2%),采用Epley管石复位法;④混合型BPPV患者12例(3.8%),采用Epley加Barbecue翻滚联合治疗。1周后随访总有效率为82.1%(261/318),3个月后随访总有效率为91.8%(292/318)。结论:结合病史,根据不同变位试验诱发的眼震特征对BPPV患者进行诊断并采用相应手法复位治疗是一种非常有效的方法,能有效缩短病程,减轻患者痛苦,可在临床广泛应用。     

Treatment of benign positional vertigo using the semont maneuver: efficacy in patients presenting without nystagmus

OBJECTIVE: To evaluate and compare the efficacy of the Semont liberatory maneuver on "objective" benign paroxysmal positional vertigo (BPPV) defined as vertigo with geotropic nystagmus in Dix-Hallpike positioning versus "subjective" BPPV defined as vertigo without nystagmus in Dix-Hallpike positioning. STUDY DESIGN: Retrospective chart review. METHODS: One hundred sixty-two patients with positional vertigo during Dix- Hallpike positioning were identified. Patients were evaluated for the presence or absence of nystagmus. All patients underwent the Semont liberatory maneuver. The patient's condition at follow-up was documented at 3 weeks as complete, partial, or failure. Repeated procedures were performed if necessary. RESULTS: There were 127 cases of objective BPPV and 35 cases of subjective BPPV. Overall, 90% of all patients tested had significant improvement of their vertigo after 1.49 maneuvers on average. Improvement was seen in 91% of patients with objective BPPV after 1.59 maneuvers on average, compared with 86% in subjective BPPV after 1.13 maneuvers on average (chi2 test, not significant [P = .5]). Patients with a history of traumatic origin or cause had an overall success rate of 81% compared with 92% for nontraumatic causes or origins (chi2 test, not significant [P = .1]). Recurrences were seen in 29% of patients after a successful initial maneuver; however, 96% of these patients responded to further maneuvers. Four patients with persistent symptoms after conservative management underwent posterior semicircular canal occlusion with resolution of symptoms. CONCLUSION: The Semont liberatory maneuver provides relief of vertigo in patients with positional vertigo, even in patients without objective nystagmus.     

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).