Weak Nystagmus Research Articles

Pediatric Benign Paroxysmal Positional Vertigo: Degree of Nystagmus and Concurrent Dizziness Differs from Adult BPPV.

Background: Benign paroxysmal positional vertigo (BPPV) is characterized by brief, intense episodes of vertigo triggered by abrupt changes in head position. It is generally accepted as being most common in adults, while it is regarded as rare in children. It is necessary to compare the disease between pediatric and adult patients for a better understanding of the disease's characteristics and its natural history. This study aimed to identify the clinical characteristics of BPPV in children and compare them with those of adult BPPV patients. Methods: All children ≤ 18 years old who were diagnosed with BPPV were selected by searching the electronic database of our hospital. Clinical features were identified by medical record review. For adult patients, we collected data from patients > 19 years of age. Results: A total of 30 pediatric (13.65 ± 4.15 years old) and 264 adult patients (60.86 ± 13.74 years old) were included in the study. Among pediatric patients, the lateral canals were involved in 80% and the posterior canals in 16.67%. In adult patients, the lateral and posterior canals were involved similarly (p = 0.007). The degree of nystagmus in pediatric patients was 6.82 ± 12.09, while in adults it was 15.58 ± 20.90 (p < 0.001). The concurrent dizziness disorder was higher in the pediatric group and recurrence was higher in the adult group. In the regression analysis, it was found that adult patients had a stronger nystagmus with a value of 6.206 deg/sec, and the risk of concurrent dizziness disorder was found to be 5.413 times higher in the pediatric group (p < 0.05). Conclusions: BPPV occurs in pediatric patients with lower prevalence, but it cannot be overlooked. In the pediatric group, a relatively high proportion of patients demonstrated lateral canal involvement, weaker nystagmus, and additional dizziness disorder.

Weak nystagmus in the dark persists for months after acute unilateral vestibular loss.

Weak nystagmus with fixation removed can be seen both in normal individuals and in recovery from a unilateral vestibular insult, thus its clinical significance is unclear in patients with dizziness. We thus sought to compare features of nystagmus at various stages following unilateral vestibular loss (UVL). We enrolled thirty consecutive patients after acute UVL with impaired vestibulo-ocular reflex (VOR) gain. The patients were allocated into three groups according to time from onset of symptoms: acute (1-7 days), subacute (8-30 days), and chronic (>30 days). Patients underwent video-oculography (with and without fixation) and video head impulse testing (vHIT) to determine VOR gain. We examined the relationships amongst SPV, VOR gain, and time from symptom onset across groups. There were 11, 10, and 9 patients in the acute, subacute, and chronic stages of UVL, respectively. With visual fixation, only 8 patients (26.7%) demonstrated nystagmus, all from the acute group. With fixation removed, 26 patients (86.7%) exhibited spontaneous nystagmus, including 90.9%, 90%, and 77.8% of the patients from the acute, subacute, and chronic groups, respectively. Horizontal nystagmus was paralytic (i.e., fast phase contralesional) in 25 (96.7%) cases. Horizontal SPV was negatively correlated with logarithm of time from onset to examination (r = -0.48, p = 0.007) and weakly negatively correlated with ipsilesional VOR gain (r = -0.325, p = 0.08). In the subacute or chronic stages of UVL, paralytic nystagmus with fixation removed persisted at a low intensity. Therefore, weak nystagmus in the dark may have diagnostic value in chronic dizziness.

Research progress on the screening questionnaire related to benign paroxysmal positional vertigo

Benign paroxysmal positional vertigo（BPPV） is the most common peripheral vestibular disease in clinical practice, which can easily lead to missed diagnosis and misdiagnosis. Many guidelines have emphasized that detailed medical history and Dix-Hallpike test are sufficient to complete the diagnosis of BPPV. However, when the patient is unable or refused to undergo the displacement test due to obesity, physical weakness, cervical or lumbar dysfunction, fear of dizziness, and the displacement test does not induce nystagmus or weak nystagmus, the detailed medical history provides a supplementary basis for the diagnosis of BPPV, and compulsive posture therapy and drug treatment can be carried out accordingly. In order to standardize consultations, shorten the time for patients to visit, and help clinicians make more accurate diagnoses, many scholars at home and abroad have designed relevant screening questionnaires based on the history of BPPV, which has achieved good results.This article is summarized as follows, in order to provide ideas and references for clinical inquiry.

Observation on nystagmus characteristics and curative effect of patients with light cupulopathy

Objective:To describe the characteristics of nystagmus in patients with Light Cupulopathy and to investigate its therapeutic effect. Method:The Supine roll test in our hospital's otology clinic showed persistent DCPN in 26 patients, who received Supine roll test, null-point position test, and prone-supine test. All patients were treated with barbecue maneuver. The immediate, short-term and long-term effects of treatment were investigated. Result:Null-point position on one side was present in 26 patients. The angles ranged from 15-45°, with an average of （26.34±8.78）°. Spontaneous nystagmus was observed in 30.8% （ 8/26 ） patients. The nystagmus was directed to the affected side in prone position and to the healthy side in supine position. Seventy-three percent of the patients had strong nystagmus and 26.9% had weak nystagmus in the Supine roll test. All patients received Barbecue maneuver, and the recovery rates were 0, 42.3% and 88.5% immediately, 1 week and 1 month after treatment respectively. There was a statistical difference in the recovery rate among immediate, one week and one month later （P<0.01）. Conclusion:The nystagmus performance of patients with persistent DCPN conforms to the light cupula hypothesis. The lesion side can be determined according to the null-point position and prone-supine test. The lesion side cannot be determined by the intensity of nystagmus in the Supine roll test in some cases. Repositioning maneuver is ineffective in treating light cupulopathy, but the disease is self-limited.

Clinical Characteristics of Acute Vestibular Neuritis According to Involvement Site.

To analyze the clinical characteristics of acute vestibular neuritis (AVN) according to involvement site. Retrospective chart analysis. Tertiary referral hospital. Over a period of 3 years, we reviewed 133 cases of AVN. Patients were classified into three groups: 1) total vestibular neuritis (superior and inferior vestibular nerve involvement [TVN]); 2) superior vestibular neuritis (superior vestibular nerve involvement [SVN]); and 3) inferior vestibular neuritis (inferior vestibular nerve involvement [IVN]). We analyzed the clinical course and results of vestibular function tests (video-nystagmography, video head impulse test [vHIT], caloric test, and cervical vestibular evoked myogenic potential). In the study, there were 39.9% TVN cases, 48.1% SVN cases, and 12% IVN cases. The number of days to spontaneous nystagmus remission, hospital duration, and follow-up period were shorter in the IVN group than in the SVN and TVN groups. The symptom onset period was longer in the IVN group than in the SVN and TVN groups. Spontaneous nystagmus and head shaking nystagmus amplitude were smaller in the IVN group than in the SVN and TVN groups. Concordance of results between the caloric test, cervical vestibular evoked myogenic potential, and vHIT was relatively low in the IVN group. The IVN group had a shorter clinical course and weaker nystagmus in comparison with the TVN and SVN groups. The use of additional vHIT in the diagnosis of AVN can help provide a more accurate diagnosis of the rare subtype of IVN, which can be confused with various central lesions.

The treatment of horizontal canal benign paroxysmal positional vertigo

The aim of our study was to assess the outcome of treatment of horizontal canal benign paroxysmal positional vertigo and to analyze the influence of the different prognostic factors on treatment failure. Fifty-nine patients with horizontal canal benign paroxysmal positional vertigo were included in the study. They were divided into two groups according to the treatment protocol, randomly. The first group, after treatment with the barbecue maneuver or inverted Gufoni, depending on the nystagmus form, was instructed to sleep on the side with weaker nystagmus, and the second group did not. In the first group, 88.9% of patients were cured and 91.3% in the second one. There was no significant difference between the two groups. Migraine and the apogeotropic form of nystagmus had a significant effect on treatment outcome, while other variables had no effect.

Bedside therapeutic experiences with horizontal canal benign paroxysmal positional vertigo (cupulolithiasis)

Conclusions. After forced prolonged position type one (FPP-one) and the appropriate repositioning maneuvers, or FPP-two, 95.45% of patients with cupulolithiasis of the horizontal semicircular canal benign paroxysmal positional vertigo (HSC-BPPV).were symptom-free. Objectives. To treat patients with cupulolithiasis of the HSC-BPPV. Subjects and methods. This was a prospective study including 22 subjects with HSC-BPPV (cupulolithiasis) based on apogeotropic direction-changing positional nystagmus (apo-DCPN). Patients adopted FPP-one, which means lying down on the side of the weaker nystagmus during nightly rest for 2 weeks. If apo-DCPN persisted, subjects adopted type two FPP (FPP-two), which means lying on the strongest nystagmus side during nightly rest for 2 weeks. Results. No vertigo or nystagmus was observed in 15 subjects after FPP-one. One subject experienced geotropic DCPN (geo-DCPN), two subjects had posterior BPPV, and another had superior BPPV. Three subjects had persistent apo-DCPN and they were subjected to FPP-two. After that, no vertigo or nystagmus was detected in two subjects. Apo-DCPN persisted in the other remaining subject after FPP-two.

Clinical Implications of a Mathematical Model of Benign Paroxysmal Positional Vertigo

Benign paroxysmal positional vertigo (BPPV) is the most commonly diagnosed vertigo syndrome. It is caused by movement of detached otoconia within the inner ear (canalithiasis) or otoconia adherent to the cupula (cupulolithiasis). A mathematical model incorporating fluid dynamics of BPPV, which results in the following insights, has been developed recently: (1) The characteristic latency of BPPV is explained by movement of detached otoconia through the ampulla, as pressure caused by moving otoconia is negligible until otoconia enter the narrow duct of the semicircular canal. Typical otoconia move at a rate of 0.2 mm/s, or about 1% of the circumference of the canal each second. (2) Particle-wall interactions can account for the considerable variability in duration and latency of BPPV. (3) Dispersion of a clump of otoconia creates more rather than less nystagmus. Thus, dispersion is not a viable explanation of fatigability. (4) Cupulolithiasis is predicted to cause a far weaker nystagmus than canalithiasis. (5) Inertial effects of treatment maneuvers cause negligible movement of otoconia.

Clinical evaluation of the monothermal caloric test.

The Torok Monothermal Caloric Test has been described as offering a strong advantage over bithermal caloric testing because it can distinguish labyrinthine from retrolabyrinthine lesions. Weak and strong irrigations of room-temperature water are administered to each ear and the ratios of strong to weak nystagmus responses compared to those of normal individuals. Ratios that fall below normal are said to represent decruitment and to denote retrolabyrinthine disease. Ratios that exceed normal are said to represent recruitment and to denote labyrinthine lesions. We attempted to verify the clinical value of the Monothermal Caloric Test by examining patients with known labyrinthine (N = 9) and retrolabyrinthine (N = 25) lesions. Ten patients with dysequilibrium and nonlocalizing testing were also examined. The test was performed exactly as described by the originator. Decruitment was found either unilaterally or bilaterally in 56% of patients with retrolabyrinthine lesions. However, it occurred on the side of the lesion in only 42%. Decruitment was also found in 47% of patients without retrolabyrinthine lesions, including 63% of those with unilateral Meniere's disease. Recruitment was never found on the side of a labyrinthine lesion. A description of the test and a summary of our results are presented. We conclude that the Monothermal Caloric Test is moderately sensitive to the presence of retrolabyrinthine lesions, but lateralizes poorly and is not highly selective. The test was found to be insensitive to the presence of labyrinthine disease.

Eye Movement Induced by Lateral Tilt and Its Clinical Significance

We have studied ocular reflexes caused by tilting stimulations in test subjects placed in an upright sitting position on a chair apparatus which tilts continuously. In healthy persons, a weak nystagmus can be observed of minor amplitude and showing a small number of beats. The actual incidence of nystagmus in the younger group was minimal, but it tended to increase with age. This occurrence is considered to be due to age-related degeneration of the otolithic organ. Patients with vertigo and/or dizziness clearly develop nystagmus. These responses are classified as follows: type I is of fixed direction: type II is of changed direction; and type III is a combination of the first and second types. Among the peripheral vestibular disorders, particularly involving patients with benign paroxysmal positional vertigo, a nystagmus of changed direction was found. This type was rarely seen in patients with other vestibular disorders, but was a common occurrence in healthy individuals who readily experienced motion sickness. These observations have led us to conclude that patients with benign paroxysmal positional vertigo have definite reactions which are similar to those of individuals with motion sickness, and that this depends on the susceptibility of the otolithic organs.

Eye movements induced by lateral tilt and testing of otolithic function.

In the last few years, we have studied ocular reflexes caused by tilting stimulations in test subjects placed in an upright sitting position on a chair apparatus which tilts continuously. In healthy persons, a weak nystagmus can be observed, and involves a nystagmus of minor amplitude and showing a small number of beats. The actual incidence of nystagmus in the younger group was minimal, but it tended to increase with age. This occurrence is considered to be due to age-related degeneration of the otolithic organ. Patients with vertigo and/or dizziness clearly develop nystagmus. These responses are classified as follows: type I is of fixed direction; type II is of changed direction; and type III is a combination of the first and second types. Among the peripheral vestibular disorders, particularly involving those patients with benign paroxysmal positional vertigo, a nystagmus of changed direction was found. This type was rarely seen in patients with other vestibular disorders, but was a common occurrence in healthy individuals who readily experienced motion sickness. These observations have led us to conclude that patients with benign paroxysmal positional vertigo have definite reactions which are similar to those of individuals with motion sickness, and that such depends on the susceptibility of the otolithic organs.

The effect of cervical and vestibular reflexes on eye movements in Huntington's chorea.

In 8 patients with manifest Huntington's Chorea vestibulo-ocular (VOR) and cervico-ocular (COR) reflexes were compared with eye movements during active head turnings. Seated patients were stimulated with their eyes closed by sinusoidal swings around the vertical axis at frequencies of 0.05, 0.1 and 0.2s-1 with amplitudes of 20, 40 and 60 degrees. 1) With all stimuli and in all patients a weak nystagmus was elicited in the direction of head movements, superimposed on larger slow eye deviations. 2) The averaged total saccadic amplitudes were smaller than in normals, increased with stimulus amplitudes and were smallest for COR, followed by VOR and active head movements. 3) The gain (peak velocity of slow phase of nystagmus to peak stimulus velocity) was only slightly below norm values and decreased with increasing stimulus frequency and amplitude. 4) The peak amplitudes of average slow eye deviations increased with stimulus amplitudes. In VOR they were comparable to norm values but were below them during COR and active head movements. 5) In normal subjects these slow eye deviations were compensatory to head movements in VOR but anticompensatory in COR and during active head movements. In choreic patients during COR and more often during active head movements these slow eye movements were compensatory for the head turning.

メニエール病の発作期眼振

The spontaneous positional nystagmus during vertiginous attacks of Ménière's disease was observed in 15 patients using the Frenzel glasses. The direction-fixed positional nystagmus toward the affected side was observed in 13 patients, and toward the non-affected side in two. In nine of the fifteen, the course of the positional nystagmus was observed. In seven patients, the positional nystagmus frequently change both the direction of the quick phase and the plane of eye-ball rotation. There were great individual variations. At about 20 hours after the onset of the vertiginous attack, there was little vertigo but a weak nystagmus was still found beating to the non-affected side in most patients. In a specific indivisual, changing of the nystagmus was similar in each attack. In the same patient, pure-tone audiometry was performed during the acute stage in addition to the observation of the positional nystagmus. The results of the pure-tone audiometry showed that the pure-tone threshold was elevated only at low-frequency ranges before the onset and it elevated at both low and high frequencies just after the vertiginous onset. Two hours following the onset, pure-tone thresholds at lower frequencies recovered. Taking all the results in the present study together, it can be speculated that during the acute vertigo in Ménière's disease, the pathology may change on an hourly basis. This would affect a part or more of the labyrinth and result in hyper- and hypo-functions of each different endorgan, which would manifest themselves in changes in spontaneous positional nystagmus. From the results of one patient, it was also speculated that the cochlear-saccular hydrops appeared before the onset, and that the disease was recovered initially in part of the cochlea, and then in the vestibular organs.

Functional organization of the mechanisms subserving the optokinetic nystagmus in the cat

In the cat both crossed and uncrossed retinal fibres are able to mediate optokinetic nystagmus in both temporonasal and nasotemporal directions. There exists, however, a slight directional predominance of the nystagmus for the crossed fibre system in the temporonasal stimulus direction and for the uncrossed fibres in a nasotemporal direction. During the first 9 days following ablation of the visual cortex the optokinetic nystagmus elicited monocularly is greatly asymmetrical: the nystagmus elicited by a temporonasal stimulus is moderately affected particularly at higher stimulus velocities, whereas the nystagmus elicited by a nasotemporal stimulus is present only at stimulus velocities below 20–30 deg/s and has a low gain. Without the visual cortex, selective stimulation of the crossed retinal fibres of one eye may evoke a weak nystagmus on temporonasal stimulus motion only. In contrast, in absence of visual cortex, the uncrossed retinal fibres do not mediate any optokinetic nystagmus. The behaviour of the vestibulo-ocular reflex in light and of the visual fixation suppression of the postrotatory nystagmus in our lesioned animals provided another means to reach similar conclusions. Twenty-seven units recorded in the vestibular nuclei showed responses to optokinetic stimulations, which were in line with the behaviour of the optokinetic nystagmus. These data suggest that optokinetic nystagmus has two components: (i), a subcortical component in which the temporonasal direction of stimulation is predominant in eliciting the nystagmus and in which both the crossed and uncrossed retinal fibres are involved, although with a different weight, and (ii), a cortical component responsible for a symmetrical optomotor response, which also involves the crossed and uncrossed retinal fibres.

Peripheral-vastibular spontaneous nystagmus. Analysis of reproducibility and methoidolgies.

With peripheral spontaneous nystagmus the intensity and its reproducibility was electronystagmorgraphically analyzed with eyes open under Frenzel's glasses and with eyes closed. 1. The maximum intensity of a spontaneous nystagmus with eyes closed is several times higher than under Frenzel's glasses. 2. A weak nystagmus can, under Frenzel's glasses, only be recognized under favorable conditions. A rather long and careful search in a totally dark room is necessary. 3. With purely peripheral lesions, the spontaneous nystagmus with closed eyes shows large intensity fluctuations, and it may disappear temporarily despite mental arithmetics. Contrary to this, with eyes open under Frenzel's glasses, the intensity fluctuation of the nystagmus is remarkably lower. Therefore, even experimental examinations with patients should be carried out electronystagmorgraphically under Frenzel's glasses. The absolute reaction is lower, but the content of information is higher because of the significantly better reproducibility.

Zur kalorischen Vestibularisdiagnostik

The relation between caloric stimuli of different temperatures of 44-0° C, in a randomized sequence, and the nystagmic reactions (measured electro-nystagmographically) was examined on patients with a peripheralvestibular disturbance, and on healthy persons. Parameters of the reaction were: duration, maximum frequency and maximum intensity of the nystagmus. The duration and the maximum frequency showed only a slight dependence on stimulus strength. But there was a linear correlation between stimuli of 30-15° C to reaction measured by maximum intensity. However, with temperatures below 15° C the reaction did not any more increase. So the maximum intensity corresponds best to the characteristics of the temperature-wave in the petrous bone and thus to the cupula-deviation. The 17°-cold strong stimulus appeared to be superior to all other cold stimuli for the following reasons: 1. Extravestibular disturbances and influences of an eventual spontaneous nystagmus are being suppressed. 2. Mistakes through wrong interpretation of very weak nystagmus become less frequent. 3. Remnants of excitability are not overlooked. 4. Every degree of hypoexcitability can be determined with a strong stimulus just as well as with the 30°-stimulus because a caloric recruitment does not exist. 5. In the temperature range of 17° a special constancy of temperature, which is mostly difficult to obtain, is less important than with 30°. Temperatures below 17° are not recommendable as the effective thermic stimulus is again decreasing when measuring via the maximum intensity whereas painful pseudocaloric nystagmus effects are accentuated. The 44°-stimulus remains, of course, obligatory. The only disadvantage, when refraining from the 30°-stimulus and when replacing it by the 17°-cold strong stimulus, is that directional preponderance cannot any more be determined. This, however, is of little importance when determining even weak spontaneous nystagmus, as the diagnostic-localizing value of directional preponderance seems questionable.