Positional nystagmus of benign paroxysmal type (BPPN) due to cerebellar vermis lesions. Pseudo-BPPN

Spontaneous Direction-Changing or Reversing Positional Nystagmus without Changing Head Position during Head-Roll/Head-Hanging Maneuvers: Biphasic Positional Nystagmus

BACKGROUND AND OBJECTIVES

Conflicting mechanisms have been reported about spontaneous reversal of positional nystagmus during head-roll maneuver in patients with benign paroxysmal positional vertigo (BPPV). The objective of this study is to review the reports about the characteristics and possible mechanisms of reversing positional nystagmus and to present seven new cases.

SUBJECTS AND METHODS

Seven cases (5 males, 2 females; 4 left-sided, 3 right-sided) were recruited among 732 patients with BPPV seen outpatient clinic between 2009 and 2019. Diagnosis of lateral canal canalolithiasis was confirmed when transient geotropic nystagmus was documented during head-roll test. Reversing positional nystagmus was analyzed in each case and clinical characteristics of the patients were documented.

RESULTS

The age of patients was ranging between 30 to 64 years (46.44±10.91). Duration of symptoms was short (21.34±19.74). Six of them had a story of head trauma. Initial latency was short. First, intense geotropic nystagmus was observed following provocative head-roll position on the affected side. There was short "silent phase". Then, a longer second-phase of reversed nystagmus was noted. Total duration of nystagmus was 78.40±6.82 seconds. Maximal slow phase velocity was 24.05±6.34 deg/sec. All patients were cured with barbeque maneuver.

CONCLUSIONS

Ipsilateral reversing positional nystagmus during head-roll maneuver is due to lateral canal canalolithiasis. Mechanism is likely to be due to endolymphatic double flow. Bilateral cases may be due to simultaneous co-existence of canalolithiasis and cupulolithiasis. Longer recording of nystagmus is recommended not to miss the cases with spontaneous direction-changing positional nystagmus.

Cost-Effective Management of bEnign Positional Vertigo Using Canalith Repositioning

OBJECTIVE: The misdiagnosis and inappropriate treatment of benign positional vertigo have resulted in significant costs to the medical system. In the current medical-economic climate, there is an increased emphasis on cost control. Recent studies have shown that the canalith repositioning procedure (CRP) is effective; the next step is to show the impact of CRP in cost-effective management of benign positional vertigo.

METHODS: Forty-six of 100 patients who underwent CRP for benign positional vertigo responded to a survey regarding the financial impact of their disease. They were asked to subjectively estimate the sum of all disease-related expenses. Objective substantiation of this number was estimated by tabulating physician data, laboratory data, and failed treatment costs.

RESULTS: The subjective figure totaled $2684.74 per individual. Summation of the tangible objective figures yielded $2009.63 per patient, corroborating the subjective figure.

CONCLUSIONS: Because CRP is a relatively simple procedure that can obviate many wasted expenses in most patients, we believe that it is very cost-effective and should be incorporated into routine practice.

Benign Paroxysmal Positional Vertigo (BPPV): History, Pathophysiology, Office Treatment and Future Directions

BPPV is the most common cause of vertigo. It most often occurs spontaneously in the 50 to 70 year age group. In younger individuals it is the commonest cause of vertigo following head injury. There is a wide spectrum of severity from inconsistent positional vertigo to continuous vertigo provoked by any head movement. It is likely to be a cause of falls and other morbidity in the elderly. Misdiagnosis can result in unnecessary tests. The cardinal features and a diagnostic test were clarified in 1952 by Dix and Hallpike. Subsequently, it has been established that the symptoms are attributable to detached otoconia in any of the semicircular canals. BPPV symptoms can resolve spontaneously but can last for days, weeks, months, and years. Unusual patterns of nystagmus and nonrepsonse to treatment may suggest central pathology. Diagnostic strategies and the simplest "office" treatment techniques are described. Future directions for research are discussed.

Central positional nystagmus simulated by a mathematical ocular motor model of otolith-dependent modification of Listing's plane

To find an explanation of the mechanisms of central positional nystagmus in neurological patients with posterior fossa lesions, we developed a three-dimensional (3-D) mathematical model to simulate head position-dependent changes in eye position control relative to gravity. This required a model implementation of saccadic burst generation, of the neural velocity to eye position integrator, which includes the experimentally demonstrated leakage in the torsional component, and of otolith-dependent neural control of Listing's plane. The validity of the model was first tested by simulating saccadic eye movements in different head positions. Then the model was used to simulate central positional nystagmus in off-vertical head positions. The model simulated lesions of assumed otolith inputs to the burst generator or the neural integrator, both of which resulted in different types of torsional-vertical nystagmus that only occurred during head tilt in roll plane. The model data qualitatively fit clinical observations of central positional nystagmus. Quantitative comparison with patient data were not possible, since no 3-D analyses of eye movements in various head positions have been reported in the literature on patients with positional nystagmus. The present model, prompted by an open clinical question, proposes a new hypothesis about the generation of pathological nystagmus and about neural control of Listing's plane.

Cost-effective management of benign positional vertigo using canalith repositioning

OBJECTIVE

The misdiagnosis and inappropriate treatment of benign positional vertigo have resulted in significant costs to the medical system. In the current medical-economic climate, there is an increased emphasis on cost control. Recent studies have shown that the canalith repositioning procedure (CRP) is effective; the next step is to show the impact of CRP in cost-effective management of benign positional vertigo.

METHODS

Forty-six of 100 patients who underwent CRP for benign positional vertigo responded to a survey regarding the financial impact of their disease. They were asked to subjectively estimate the sum of all disease-related expenses. Objective substantiation of this number was estimated by tabulating physician data, laboratory data, and failed treatment costs.

RESULTS

The subjective figure totaled $2684.74 per individual. Summation of the tangible objective figures yielded $2009.63 per patient, corroborating the subjective figure.

CONCLUSIONS

Because CRP is a relatively simple procedure that can obviate many wasted expenses in most patients, we believe that it is very cost-effective and should be incorporated into routine practice.

Benign paroxysmal positional vertigo

Benign paroxysmal positional vertigo is a common disorder of the inner ear that should be suspected in all patients with a history of positionally provoked vertigo. The condition appears to be caused by free-floating debris in the posterior semicircular canal. The diagnosis is confirmed by eliciting characteristic symptoms and signs during the Dix-Hallpike test. Although benign paroxysmal positional vertigo is usually a self-limited disorder, treatment with a specific bedside maneuver is effective and can provide the patient immediate and long-lasting relief. Although many patients with positionally provoked vertigo have typical benign paroxysmal positional vertigo, physicians should be aware of nonbenign variants.

Localization of static positional nystagmus with the ocular fixation test

OBJECTIVE

Characteristics of static positional nystagmus (SPN) (i.e., persistency, direction fixed, direction changing) are observed in both peripheral and central disturbances and possess no localizing value for vestibular lesions. Our objective was to investigate whether the ocular fixation test as applied to SPN could assist in localizing vestibular lesions.

STUDY DESIGN

A 3-year prospective study that included 43 patients with SPN.

METHODS

All patients underwent a standard vestibular test battery and cerebral imaging (7, computed tomography scan; 36, magnetic resonance imaging). The ocular fixation index (OFI) was calculated by the ratio of the mean slow component velocity of SPN (measured with red light-emitting diode fixation) to that measured in darkness, multiplied by 100. An OFI less than 50 was considered normal.

RESULTS

In 33 of 35 patients whose OFI was less than 50, the cerebral imaging was normal and a peripheral vestibular lesion was diagnosed (two benign tumors of the fourth ventricle were missed). In all eight patients whose OFI was greater than 50, the cerebral imaging was abnormal and a central vestibular lesion was noted.

CONCLUSIONS

These results indicate that the visual suppression of SPN does, indeed, permit the localization of vestibular lesions. The predictive value of the ocular fixation test on the origin of SPN is greater than 94% for peripheral lesions and 100% for central disorders.

A review of management of benign paroxysmal positional vertigo by exercise therapy and by repositioning manoeuvres

Benign paroxysmal positional vertigo (BPPV) is a common condition that often resolves spontaneously, but can cause significant distress to a patient. Management of this condition includes no intervention, medication, surgery, physical exercises and more recently 'particle repositioning' manoeuvres. Repositioning manoeuvres aim to relocate free-floating particles from the posterior semicircular canal into the utricle where they will no longer cause vertiginous symptoms. This article describes the different exercises and repositioning manoeuvres in use and examines their efficacy. In the light of this review a management strategy for BPPV is suggested.

Atypical "reversed" paroxysmal positioning nystagmus in benign paroxysmal positional vertigo

An atypical paroxysmal positioning nystagmus (PPNy), "reversed" in its directional components, is a rare finding in patients suffering from benign paroxysmal positioning vertigo (BPPV). It poses problems of pathophysiogenetic interpretation, differential diagnosis with a CNS lesion and therapeutic strategy. Such a finding was observed in 7 patients (out of a total of 450 BPPV) and took on the typical PPNy pattern after repeated diagnostic manoeuvres. These aspects are incompatible with the "heavy cupula" mechanism (cupulolithiasis) and are better explained by the presence of "free endolymph aggregates" (canalolithiasis) within the posterior semicircular canal (p.s.c). Moreover, canalolithiasis would also permit a more convincing interpretation of all the clinical findings observed in typical p.s.c.-BPPV.