Nystagmus findings in healthy subjects examined with infrared videonystagmoscopy

Positional nystagmus is observed in the vast majority of healthy individuals

INTRODUCTION

Benign paroxysmal positional vertigo (BPPV) is a vestibular disease characterized by brief  positional vertigo. When examined, characteristic patterns of positional nystagmus (PN) are found with specific head position changes. Previous studies have shown a high prevalence of PN among vestibular healthy subjects. Considering the current diagnostic criteria of BPPV and the potentially high prevalence of PN in healthy individuals, this raises the question of potential over diagnosing BPPV, if diagnostics are based exclusively upon objective findings. This study aims to determine the prevalence of PN within a healthy, adult population and furthermore include a characterization of the PN observed.

METHODS

This is a prospective cross-sectional study. 78 subjects were included. The subjects underwent four standardized positional tests for BPPV in a mechanical rotational chair while using a VNG-goggle to monitor and record eye movements.

RESULTS

Positional nystagmus was recorded in 70.5% (55/78) of the subjects. Of the 55 subjects, who presented with PN, 81.8% (45/55) had upbeating PN. The 95th percentile of the maximum a-SPV was found to be 10.4 degrees per second, with a median of 4. Five subjects (6.4%) in total presented with PN mimicking BPPV.

CONCLUSION

This study found PN to be a common finding within a healthy, adult population based on the high prevalence of PN in the study population. Upbeating PN mimicking posterior canalolithiasis was found in numerous subjects. The authors recommend a cautious approach when diagnosing BPPV, especially in cases of purely vertical PN (without a torsional component) and if no vertiginous symptoms are present during Dix-Hallpike and Supine Roll Test examinations.

Clinical, oculographic, and vestibular test characteristics of vestibular migraine

BACKGROUND

We characterise the history, vestibular tests, ictal and interictal nystagmus in vestibular migraine.

METHOD

We present our observations on 101 adult-patients presenting to an outpatient facility with recurrent spontaneous and/or positional vertigo whose final diagnosis was vestibular migraine (n = 27) or probable vestibular migraine (n = 74). Ictal and interictal video-oculography, caloric and video head impulse tests, vestibular-evoked myogenic potentials and audiometry were performed.

RESULTS

Common presenting symptoms were headache (81.2%), spinning vertigo (72.3%), Mal de Débarquement (58.4%), and motion sensitivity (30.7%). With fixation denied, ictal and interictal spontaneous nystagmus was observed in 71.3 and 14.9%, and purely positional nystagmus in 25.8 and 55.4%. Spontaneous ictal nystagmus was horizontal in 49.5%, and vertical in 21.8%. Ictal spontaneous and positional nystagmus velocities were 5.3 ± 9.0°/s (range 0.0-57.4), and 10.4 ± 5.8°/s (0.0-99.9). Interictal spontaneous and positional nystagmus velocities were <3°/s in 91.8 and 23.3%. Nystagmus velocities were significantly higher when ictal (p < 0.001/confidence interval: 2.908‒6.733, p < 0.001/confidence interval: 5.308‒10.085). Normal lateral video head impulse test gains were found in 97.8% (mean gain 0.95 ± 0.12) and symmetric caloric results in 84.2% (mean canal paresis 7.0 ± 23.3%). Air- and bone-conducted cervical-vestibular-evoked myogenic potential amplitudes were symmetric in 88.4 and 93.4% (mean corrected amplitude 1.6 ± 0.7, 1.6 ± 0.8) with mean asymmetry ratios of 13.0 and 9.0%. Air- and bone-conducted ocular-vestibular-evoked myogenic potentials were symmetric in 67.7 and 97.2% (mean amplitude 9.2 ± 6.4 and 20.3 ± 12.8 µV) with mean asymmetry ratios of 15.7 and 9.9%. Audiometry was age consistent and symmetric in 85.5%.

CONCLUSION

Vestibular migraine is characterised by low velocity ictal spontaneous nystagmus, which can be horizontal, vertical, or torsional, and normal audiovestibular test results.

Nystagmus characteristics of healthy controls

BACKGROUND:

Healthy controls exhibit spontaneous and positional nystagmus which needs to be distinguished from pathological nystagmus.

OBJECTIVE:

Define nystagmus characteristics of healthy controls using portable video-oculography.

METHODS:

One-hundred and one asymptomatic community-dwelling adults were prospectively recruited. Participants answered questions regarding their audio-vestibular and headache history and were sub-categorized into migraine/non-migraine groups. Portable video-oculography was conducted in the upright, supine, left- and right-lateral positions, using miniature take-home video glasses.

RESULTS:

Upright position spontaneous nystagmus was found in 30.7% of subjects (slow-phase velocity (SPV)), mean 1.1±2.2 degrees per second (°/s) (range 0.0 – 9.3). Upright position spontaneous nystagmus was horizontal, up-beating or down-beating in 16.7, 7.9 and 5.9% of subjects. Nystagmus in at least one lying position was found in 70.3% of subjects with 56.4% showing nystagmus while supine, and 63.4% in at least one lateral position. While supine, 20.8% of subjects showed up-beating nystagmus, 8.9% showed down-beating, and 26.7% had horizontal nystagmus. In the lateral positions combined, 37.1% displayed horizontal nystagmus on at least one side, while 6.4% showed up-beating, 6.4% showed down-beating. Mean nystagmus SPVs in the supine, right and left lateral positions were 2.2±2.8, 2.7±3.4, and 2.1±3.2°/s. No significant difference was found between migraine and non-migraine groups for nystagmus SPVs, prevalence, vertical vs horizontal fast-phase, or low- vs high-velocity nystagmus (<5 vs > 5°/s).

CONCLUSIONS:

Healthy controls without a history of spontaneous vertigo show low velocity spontaneous and positional nystagmus, highlighting the importance of interictal nystagmus measures when assessing the acutely symptomatic patient.

10.5 T MRI static field effects on human cognitive, vestibular, and physiological function

PURPOSE

To perform a pilot study to quantitatively assess cognitive, vestibular, and physiological function during and after exposure to a magnetic resonance imaging (MRI) system with a static field strength of 10.5 Tesla at multiple time scales.

METHODS

A total of 29 subjects were exposed to a 10.5 T MRI field and underwent vestibular, cognitive, and physiological testing before, during, and after exposure; for 26 subjects, testing and exposure were repeated within 2-4 weeks of the first visit. Subjects also reported sensory perceptions after each exposure. Comparisons were made between short and long term time points in the study with respect to the parameters measured in the study; short term comparison included pre-vs-isocenter and pre-vs-post (1-24 h), while long term compared pre-exposures 2-4 weeks apart.

RESULTS

Of the 79 comparisons, 73 parameters were unchanged or had small improvements after magnet exposure. The exceptions to this included lower scores on short term (i.e. same day) executive function testing, greater isocenter spontaneous eye movement during visit 1 (relative to pre-exposure), increased number of abnormalities on videonystagmography visit 2 versus visit 1 and a mix of small increases (short term visit 2) and decreases (short term visit 1) in blood pressure. In addition, more subjects reported metallic taste at 10.5 T in comparison to similar data obtained in previous studies at 7 T and 9.4 T.

CONCLUSION

Initial results of 10.5 T static field exposure indicate that 1) cognitive performance is not compromised at isocenter, 2) subjects experience increased eye movement at isocenter, and 3) subjects experience small changes in vital signs but no field-induced increase in blood pressure. While small but significant differences were found in some comparisons, none were identified as compromising subject safety. A modified testing protocol informed by these results was devised with the goal of permitting increased enrollment while providing continued monitoring to evaluate field effects.

Capturing acute vertigo

Objective

To facilitate the diagnosis of vestibular disorders by patient-initiated capture of ictal nystagmus.

Methods

Adults from an Australian neurology outpatient clinic reporting recurrent vertigo were recruited prospectively and taught to self-record spontaneous and positional nystagmus at home while symptomatic, using miniature video-oculography goggles. Consenting patients with ictal videorecordings and a final unblinded clinical diagnosis of Ménière disease (MD), vestibular migraine (VM), or benign paroxysmal positional vertigo (BPPV) were included.

Results

Ictal eye videos of 117 patients were analyzed. Of 43 patients with MD, 40 showed high-velocity spontaneous horizontal nystagmus (median slow-phase velocity [SPV] 39.7°/s; 21 showed horizontal nystagmus reversing direction within 12 hours [24 on separate days]). In 44 of 67 patients with VM, spontaneous horizontal (n = 28, 4.9°/s), upbeating (n = 6, 15.5°/s), or downbeating nystagmus (n = 10, 5.1°/s) was observed; 16 showed positional nystagmus only, and 7 had no nystagmus. Spontaneous horizontal nystagmus with SPV >12.05°/s had a sensitivity and specificity of 95.3% and 82.1% for MD (95% confidence interval [CI] 0.84–0.99, 0.71–0.90). Nystagmus direction change within 12 hours was highly specific (95.7%) for MD (95% CI 0.85–0.99). Spontaneous vertical nystagmus was highly specific (93.0%) for VM (95% CI 0.81–0.99). In the 7 patients with BPPV, spontaneous nystagmus was absent or <3°/s. Lying affected-ear down, patients with BPPV demonstrated paroxysmal positional nystagmus. Median time for peak SPV to halve (T50) was 19.0 seconds. Patients with VM and patients with MD demonstrated persistent positional nystagmus (median T50; 93.1 seconds, 213.2 seconds). T50s <47.3 seconds had a sensitivity and specificity of 100% and 77.8% for BPPV (95% CI 0.54–1.00, 0.64–0.88).

Conclusion

Patient-initiated vestibular event monitoring is feasible and could facilitate rapid and accurate diagnosis of episodic vestibular disorders.

Prevalence and Characteristics of Positional Nystagmus in Normal Subjects

OBJECTIVE

In clinical practice, patients are often referred due to a finding of positional nystagmus that does not always appear to correlate with clinical symptoms of benign paroxysmal positional vertigo. To know when to consider nystagmus to be of clinical relevance, it is necessary to know the prevalence and characteristics of positional nystagmus in a healthy population.

STUDY DESIGN

Case series of 75 healthy subjects.

SETTING

Two tertiary referral centers in Norway.

SUBJECTS AND METHODS

Seventy-five adult subjects aged 40 ± 13 years (mean ± SD; range, 21-87) without a history of vertigo or balance disorder were included from 2013 to 2015. The subjects underwent 6 different standardized positional tests in a repositioning chair. Videonystagmography was used to record eye movements. Of 1350 recordings, 1329 were included and analyzed.

RESULTS

Positional nystagmus was detected in 88% of the subjects. The most common finding was nystagmus in the Dix-Hallpike position, which occurred in 55% of the subjects. The 95th percentile of the maximum slow-phase velocity for each subject was found to be 5.06° per second (n = 54) in the horizontal plane and 6.48° per second (n = 48) in the vertical plane.

CONCLUSION

Positional nystagmus is a common finding in normal subjects and occurred in 88% of the healthy subjects in the present study. Horizontal direction-changing apogeotropic or geotropic nystagmus may occur in asymptomatic subjects. However, nystagmus that is of the paroxysmal type or has a slow-phase velocity greater than approximately 5° per second in the horizontal plane or 6.5° per second in the vertical plane should be considered outside the 95th percentile.

The Vestibular Effects of Repeated Low-Level Blasts

The objective of this study was to use a prospective cohort of United States Marine Corps (USMC) instructors to identify any acute or long-term vestibular dysfunction following repeated blast exposures during explosive breaching training. They were assessed in clinic and on location during training at the USMC Methods of Entry School, Quantico, VA. Subjects received comprehensive baseline vestibular assessments and these were repeated in order to identify longitudinal changes. They also received shorter assessments immediately following blast exposure in order to identify acute findings. The main outcome measures were the Neurobehavioral Symptom Inventory, vestibular Visual Analog Scale (VAS) of subjective vestibular function, videonystagmography (VNG), vestibular evoked myogenic potentials (VEMP), rotary chair (including the unilateral centrifugation test), computerized dynamic posturography, and computerized dynamic visual acuity. A total of 11 breachers and 4 engineers were followed for up to 17 months. No acute effects or longitudinal deteriorations were identified, but there were some interesting baseline group differences. Upbeat positional nystagmus was common, and correlated (p<0.005) with a history of mild traumatic brain injury (mTBI). Several instructors had abnormally short low-frequency phase leads on rotary chair testing. This study evaluated breaching instructors over a longer test period than any other study, and the results suggest that this population appears to be safe from a vestibular standpoint at the current exposure levels. Upbeat positional nystagmus correlated with a history of mTBI in this population, and this has not been described elsewhere. The data trends also suggest that this nystagmus could be an acute blast effect. However, the reasons for the abnormally short phase leads seen in rotary chair testing are unclear at this time. Further investigation seems warranted.

Vestibular findings in patients with persistent geotropic positional nystagmus: the 'light cupula' phenomenon

CONCLUSIONS

Persistent geotropic nystagmus indicates a condition of a light cupula, which is accompanied by vestibular disability and a high incidence of pathological findings in the vestibular tests. The prevalence of migraine is high.

OBJECTIVES

To examine subjective symptoms and characteristics of nystagmus in patients with persistent geotropic nystagmus using vestibular tests, as well as possible correlations to migraine in this group.

METHODS

We enrolled 20 patients with a mean age of 53 years. The slow phase velocity (SPV) of the geotropic nystagmus and the nystagmus with the patient's head in the supine (S) and prone (P) positions was recorded. All patients completed caloric tests, subjective visual horizontal (SVH), and vestibular evoked myogenic potential (VEMP). All tests were repeated at follow-up (FU).

RESULTS

SPV of the geotropic nystagmus directed to the left was 5.5°/s and that to the right was 3.5°/s. In 72% of patients, nystagmus in the P position was opposite to that in the S position. The vestibular tests were pathologic in about 60% of patients. At FU geotropic nystagmus was found in 40% of patients, but was significantly less intense. The vestibular test results remained at the same level at FU. Recurrent vertigo was reported in 78% of the patients. In all, 40% of the patients suffered from migraine.

Immediate postoperative nystagmus and vestibular symptoms after stapes surgery

CONCLUSION

Vestibular disturbance is frequent, but mild even immediately after stapes surgery. Vestibular symptoms improved or disappeared quickly, and they did not correlate with nystagmus. Outpatient stapes surgery performed under local anaesthesia is a feasible approach.

OBJECTIVE

Vestibular symptoms are common and may prevent outpatient surgery. The time course of vestibular disturbance is unclear, and we aimed to evaluate it immediately after the operation in the recovery room.

METHODS

Twenty patients with otosclerosis undergoing stapedotomy were prospectively included in the study. Postoperative symptoms were collected and nystagmus was recorded with video-oculography (VOG) on average 29 min after the surgery.

RESULTS

None of the patients had spontaneous nystagmus with gaze fixation. Nine patients (45%) had slow spontaneous horizontal nystagmus (mean slow phase velocity of 1.1°/s) in the primary position without gaze fixation. In seven of these, the nystagmus obeyed Alexander's law. Nine patients (45%) had vestibular symptoms at the end of the surgery, and four patients at the time of VOG recording. Vertigo was experienced immediately after the operation in five, floating sensation in two, and unspecific dizziness in two patients. Vestibular symptoms were mild or moderate in most patients. The occurrence of nystagmus did not correlate with vestibular symptoms (p > 0.05).

Is the nystagmus pattern in hemi-labyrinthectomized subjects during positional alcohol nystagmus 2 similar to that found in patients with cupulolithiasis in the lateral semicircular canal?

CONCLUSION

A positional nystagmus pattern compatible with a condition of a heavy cupula (cupulolithiasis) in the lateral semicircular canal could be reproduced in hemi-labyrinthectomized subjects during positional alcohol nystagmus 2 (PAN 2). The nystagmus pattern was opposite to that found in the same subjects during PAN 1. The affected side could not be judged by applying Ewald's second law.

OBJECTIVES

To mimic the condition of a heavy cupula in the lateral semicircular canal by using unilaterally deafferented subjects during PAN 2 and compare (a) results reported in the literature with those of patients with cupulolithiasis, and (b) the nystagmus findings in the same subjects during PAN 1.

METHODS

Five hemi-labyrinthectomized subjects were studied during PAN 2 when they kept their heads pointed straight forward or turned sideways in the prone and supine positions, respectively.

RESULTS

When the subjects were examined with their heads turned in the supine or prone positions, the alcohol-induced nystagmus pattern was compatible with that of cupulolithiasis. When the head was pointed straight forward in the prone and supine positions, the nystagmus directions were opposite to those found during PAN 1. Directional preponderance was not seen for the apogeotropic nystagmus for either ampullofugal or ampullopetal deviation of the cupula.

Can the nystagmus pattern in patients with a 'light cupula' be reproduced in hemi-labyrinthectomized subjects during positional alcohol nystagmus 1?

CONCLUSION

A positional nystagmus pattern compatible with a condition of a light cupula in the lateral semicircular canal seen in clinical patients could be reproduced only partially in hemi-labyrinthectomized subjects during the stage of positional alcohol nystagmus 1 (PAN 1).

OBJECTIVES

To mimic the condition of a light cupula in the lateral semicircular canal by using unilaterally deafferented subjects during the stage of PAN 1 and compare the results with those of patients with a light cupula.

METHODS

Five hemi-labyrinthectomized subjects were studied during PAN 1 with videonystagmography when they kept their heads straight forward or turned sideways in the prone and supine positions, respectively. A zero zone, indicating a cupula dysfunction, in which the geotropic nystagmus changed direction during slow head turn in the supine position, was also looked for.

RESULTS

When the subjects were examined with their heads turned left or right in the supine or prone positions, the alcohol-induced nystagmus pattern was compatible with that of a light cupula. However, the nystagmus directions at the head straight forward in the prone and supine positions, as well as localization of the zero zones, deviated from the pattern seen in patients with a light cupula.

Benign paroxysmal positional vertigo and clinical test of sensory interaction and balance in ankylosing spondylitis

OBJECTIVE

To assess the frequency and characteristics of benign paroxysmal positional vertigo (BPPV) and clinical test of sensory interaction and balance (CTSIB) abnormalities in patients with ankylosing spondylitis (AS).

STUDY DESIGN

A series of consecutive patients that fulfilled the modified New York diagnostic criteria for AS and matched controls were studied.

SETTING

The study was performed at the Otolaryngology Division of a tertiary reference center.

PATIENTS

Fifty-nine patients with AS (47 men [79.6%]) attending hospital outpatient rheumatology clinics between March and October 2008, and 46 controls (34 men [73.9%]) were studied.

INTERVENTION

Dix-Hallpike and cephalic rotational tests and CTSIB were performed in AS patients and age-, sex-, and ethnically frequency-matched controls.

MAIN OUTCOME MEASURE

Type and frequency of BPPV and CTSIB conditions were assessed.

RESULTS

BPPV was diagnosed in 6 patients (10.1%) with AS and in 2 (4.3%) of the controls (p = 0.24). Abnormal caloric test was more commonly observed in patients with AS (n = 15 [25.4%]) than the controls (n = 0) (p < 0.001). Increased frequency of abnormal CTSIB also was observed in patients (19/59 [32%]) compared with the controls (3 [6.5%]) (odds ratio, 6.81 [95% confidence interval, 1.77-38.0]; p = 0.001). Among the abnormal CTSIB patterns, the vestibular loss was the most commonly observed in patients with AS (15/59 [25.4%]).

CONCLUSION

The present study shows an increased frequency of abnormal postural control in CTSIB test of vestibular origin in patients with AS.

Active versus passive head-shaking nystagmus

CONCLUSIONS

We recommend performing the test for nystagmus actively, both when the response is analyzed at bedside or with videonystagmography. If no nystagmus is observed with the active test, it should then be performed passively.

OBJECTIVE

Head-shaking nystagmus (HSN) is a sign of vestibular dysfunction that is elicited after actively (patient) or passively (examiner) shaking a patient's head. The objective of this study was to analyze the frequency of HSN when the test is performed actively (aHSN) or passively (pHSN), and to determine whether any differences in the results might be due to age or disease state, or whether they reflect the results of different vestibular tests.

PATIENTS AND METHODS

This was a prospective study conducted at a tertiary care center. The head-shaking test was carried out actively and passively on 100 patients. The caloric test, the rotatory chair tests and the measures of disability were performed on the same day and in the same setting. HSN was considered to be present when it was seen for a period longer than 5 s or if the maximum slow-phase velocity of HSN was higher than 3 degrees s(-1). Four groups were established according to the results of the two testing methods.

RESULTS

The frequency of aHSN was 47% and of pHSN was 46% when the presence of nystagmus was established as the criterion. Moreover, in patients who had experienced vestibular neuritis previously, the type of nystagmus was age-dependent. When the velocity of the nystagmus elicited was considered, the results coincided with the method of testing in 74% of the patients, while they differed in 26% of subjects; the aforementioned age dependency was no longer seen. Differences in the caloric and rotatory chair test results, as well as in disability, were observed in the groups generated on the basis of the types of nystagmus.

Video-oculography findings in patients with otosclerosis

OBJECTIVE

To evaluate the existence of vestibular irritation with video-oculography before and after stapes surgery and to examine whether there would be signs of specific end-organ irritation.

STUDY DESIGN

A prospective study of preoperative and postoperative nystagmus, vertigo, and hearing thresholds.

SETTING

University hospital, tertiary referral center.

PATIENTS

Thirty-three patients (mean age, 47 yr) with otosclerosis.

INTERVENTION

Stapedotomy/stapedectomy with laser or microdrill.

MAIN OUTCOME MEASURES

Spontaneous, gaze-evoked, and head-shaking nystagmus was measured preoperatively and approximately 1 week, 1 month, and 3 months after the operation. Three dimensions of nystagmus were identified and their slow-phase velocities were calculated.

RESULTS

Spontaneous horizontal nystagmus was found preoperatively in 18% (slow-phase velocities, 1.3-3.3 deg/s) and postoperatively in 11 to 19% of the patients (slow-phase velocities, 1.3-3.8 deg/s). Head-shaking nystagmus was not detected preoperatively. After the operation, 11 to 15% of the patients had head-shaking nystagmus (slow-phase velocities, 6.6-17.8 deg/s), but this prevalence did not differ statistically significantly from the preoperative level (p = 0.18). Vertical nystagmus was found equally pre- and postoperatively. Torsional nystagmus was not found. One week after the operation, nine patients (27%) had some sensation of vertigo, but it lasted over 1 month in only one patient. We found no significant correlation with vertigo and the types of nystagmus.

CONCLUSION

Nystagmus with a low slow-phase velocity can occur in patients with otosclerosis. However, according to the video-oculographic findings and subjective symptoms, significant vestibular dysfunction seems to be rare and temporary after stapes surgery.

Valores poblacionales de referencia para videooculografía en el test de agitación cefálica y la prueba calórica bitérmica

OBJECTIVE

To obtain reference values for the vestibulo-ocular reflex response to the head-shaking nystagmus and the bithermal caloric test in the spanish population.

PATIENTS AND METHODS

DESIGN

A descriptive study. SET UP: General hospital.

INDIVIDUALS

One hundred and seven healthy sex and age stratified voluntiers were included. The final sample included 97 individuals over 18 years of age.

INTERVENTION

Spontaneous nystagmus (SN), head-shaking nystagmus (HSN) and caloric induced nystagmus were explored. The eyes movement was recorded by a video-oculographic system. The SN or HSN was considered significant when at least 6 consecutive beats with a slow phase velocity of 2 degrees/sec were detected. The caloric test was performed with water flow at 250mL/20 s at 30 degrees C and 44 degrees C with an interval of 10 minutes between irrigations. The percentage of canal paresis (CP) and directional preponderance (DP) was calculated using maximum slow phase velocity and the Jongkees index formula.

MAIN OUTCOME MEASUREMENTS

Presence of SN, horizontal and vertical SHN, percentage of CP and DP.

RESULTS

SN was found in 10,3% individuals (6 women and 4 men). Horizontal HSN was also observed in 9 women and 10 men (19,5%), and vertical HSN in 8 women and 10 men (18,6%). The mean and 95 percentil for CP were 13,10 and 28,60 in women and 11,02 and 27,30 in men. For DP, the mean and 95 percentil were 11,76 and 35,80 in women and 11,58 and 28,65 in men. The 5 percentils for slow phase velocity of nystagmus after each irrigation were 6,30; 5,14; 5,96; 4,02 degrees/s (left ear 44 degrees, right ear 44 degrees, left ear 30 degrees, right ear 30 degrees, respectively) in the group of women; and 5,82; 6,99; 5,67; 4,55 degrees/s in men (with the same irrigation sequence).

CONCLUSION

Results presented should be considered as a population-based norms and may be useful as references for water bithermal test for VOG studies. The SN or HSN could be observed in subjects without vestibular pathology.

Trigeminal stimulation elicits a peripheral vestibular imbalance in migraine patients

OBJECTIVE

The study explored the hypothesis that spontaneous nystagmus (Ny) in migraine patients can be triggered or modulated by painful trigeminal stimulation, providing evidence of a functional connection between vestibular and trigeminal systems.

BACKGROUND

Vertigo attacks are reported by subjects with migraine or a familiar history of migraine, also independently of headache episodes. Idiopathic vertigo is three times more frequent in migraine patients than in controls. Vestibular investigations in migraine patients have consistently demonstrated spontaneous Ny both of central and peripheral origin.

DESIGN

In the first phase of the study 10 outpatients experiencing migraine without aura (MO) and 10 healthy volunteers were submitted to the registration of spontaneous primary-position Ny in the dark by Ulmer's video-ocular-nystagmographic equipment. Two electrodes for electrical stimulation were applied on the supraorbital point of one side of the head and the intensity of stimulation corresponding to pain threshold was calculated. Spontaneous ocular movements were recorded for 5 minutes at baseline and after a sequence of five electric pulses (square waves of .5 Hz frequency and 50 micros duration, at pain threshold intensity). Nystagmographic responses were expressed as latency after stimulation, direction of the quick phase, and duration. The second phase of the study explored, with the same procedure, the effects on Ny of supraorbital versus median nerve stimulation in other 10 MO patients. Responses to stimulation were considered the appearance of de novo Ny after stimulation in subjects without baseline Ny, or the change of the frequency (at last a 50% variation) or of the direction of Ny after stimulation in subjects with baseline Ny. The latency and the duration of responses to stimulation were also calculated.

RESULTS

In the first series supraorbital painful electric stimulation was able to modify or to evoke Ny in 8 of 10 migraineurs and in none of 10 volunteers (Fisher's exact test, P<.01). Both the baseline and the induced Ny were second degree, stationary persistent, with a linear slow phase and were suppressed by visual fixation. In the second series, supraorbital nerve stimulation was able to induce or modify Ny in all of 10 patients but only in 1 patient Ny was induced by median nerve stimulation. Characters of Ny were the same as previously described. Statistical comparison of the responses at the two sites of stimulation was significant (Fisher's exact test, P<.01). In those 7 patients who presented de novo Ny after stimulation it was possible to calculate Ny latency and duration. The mean latency was 25 s (SD: 16, range: 14 to 60). The mean duration was 120 s (SD: 94, range: 20 to 290).

CONCLUSION

The main result of our study is that in migraine patients painful trigeminal stimulation elicits de novo, or modifies pre-existing spontaneous Ny, generally increasing it. The finding was obtained after trigeminal stimulation, but not after median nerve stimulation. We suggest that painful trigeminal stimulation can induce an imbalance of the vestibular system in migraine patients and possibly explain their predisposition to vertigo. Our data require confirmation by other studies.

[Kinetic tests representativity in vestibular function]

INTRODUCTION

The most frecuently tests used to study the vestibular system, with videonystagmographic register, are the caloric and rotatory ones.

MATERIAL AND METHODS

We have carried out a comparative study of the kinetic tests through a sample of 41 patients without vestibular pathology, stratified by age and gender. The performed rotational tests have been: Constant/cycles, postrrotatory test, increasing, decreasing and constant test.

RESULTS

We have not observed age or gender influence on the results. We give the numeric results of these tests.

CONCLUSION

The obtained data allow to conclude that the information given by the increasing and decreasing pendulous test is similar, phenomenon that doesn't happen in the rest of the practiced tests. We also study the habituation phenomenon to a know stimuli. We point out the importance of each laboratory to have their tests done previously in a normal control group in order to compare the results when performing them in pathological patients.

Nystagmus Measured with Video-Oculography: Methodological Aspects and Normative Data

Detailed analysis of eye movements is essential in order to understand the pathophysiology underlying vestibular disturbances. We applied a commercial video-oculography (VOG) to measure spontaneous and provoked nystagmus in 20 healthy subjects. The slow-phase velocity (SPV) of the nystagmus was calculated. We also simultaneously recorded the eye movements on a standard VHS videotape to be able to confirm the results derived from the VOG paper charts. The nystagmus results derived from the VOG charts and the simultaneous videotaping agreed well. Nystagmus was found in 17 subjects. Spontaneous nystagmus was seen in 20%, positional nystagmus in 55%, and head-shaking nystagmus in 35% of the participants. Although nystagmus was frequent (85%), the mean SPV for nystagmus was low (1.7 degrees /s). The VOG is a modern and sensitive method to record eye movements, but visual inspection of the videotape may be needed in selected cases to confirm occurrence of nystagmus.

Giant Cell Arteritis: A New Association with Benign Paroxysmal Positional Vertigo

OBJECTIVE

To assess the incidence and characteristics of both benign paroxysmal positional vertigo (BPPV) and positional nystagmus in a series of patients with giant cell arteritis (GCA).

STUDY DESIGN

Patients diagnosed with GCA between June 1999 and May 2001 at the single hospital for a defined population were examined prospectively.

METHOD

Patients included in this study fulfilled the 1990 American College of Rheumatology classification criteria for GCA. Otologic and oculographic studies were performed. Type, frequency, and outcome of positional oculographic findings was assessed. Patients were required to have been examined within 1 week after the onset of corticosteroid therapy. Data found in GCA patients were compared with those observed in an age, sex, and ethnically matched control population. Further studies in patients and controls were performed 3 and 6 months later.

RESULTS

Forty-four patients and 44 matched controls were included in this study. Nine (20.5%) GCA patients fulfilled diagnostic criteria of BPPV compared with only 1 (2.3%) of the controls (P =.007). In seven of these nine GCA patients, BPPV was related to the posterior and two to the horizontal semicircular canals, respectively. Horizontal nystagmus was found in seven GCA patients who developed nystagmus in the head hanging position test compared with none in the controls (P =.006).

CONCLUSIONS

The present study shows a higher frequency of BPPV in GCA than in matched controls. Because most clinical manifestations in GCA are caused by ischemic complications, our results suggest an ischemic etiology as responsible for BPPV in these elderly patients. According to these results, GCA may constitute a new association with BPPV.

[Video-nystagmography findings in healthy elderly subjects]

This study investigated 44 healthy elderly subjects aged between 64 and 87, who were analysed with videonystagmoscopy and quantitative videonystagmography, for establishing new standards for normal limits into this new diagnostic tool. 15.9% of the subjects were found to have spontaneous and provoked nystagmus at least in one position studied. Vertical nystagmus in head hanging position was the most frequent finding. In the Dix-Hallpike test we found one case of torsional nystagmus. No subject had seated position nystagmus. Nystagmus after head shaking and evoked nystagmus were not found.

Audiovestibular manifestations in giant cell arteritis: a prospective study

Giant cell arteritis (GCA) is a multisystemic vasculitis of elderly people that involves large and medium-sized blood vessels with predisposition to the cranial arteries. Some cranial ischemic manifestations, in particular permanent visual loss, have been widely described. Audiovestibular manifestations have been less commonly reported. In the present study we assessed the frequency and outcome of audiovestibular manifestations in a series of GCA and isolated polymyalgia rheumatica (PMR) patients examined prospectively between June 1999 and May 2001 at the single hospital for a defined population. Patients were included in the study if a temporal artery biopsy had been performed and they were examined within a week after beginning corticosteroid treatment. Patients with abnormal otoscopy or tympanogram, history of cerebrovascular complications, syphilis, Ménière and other vestibular syndromes, infections involving the inner ear, barotrauma, or being treated with ototoxic drugs were excluded. During the study period 44 patients with GCA and 10 patients with biopsy-negative isolated PMR were examined. Patients with isolated PMR were younger. Audiovestibular dysfunction was significantly more frequent in GCA patients than in those with isolated PMR and matched controls. Almost 90% of the GCA patients had vestibular dysfunction, which was generally reversible after several days of steroid treatment; after 3 months of treatment, vestibular dysfunction was observed in only 13 (29.6%) of the 44 GCA patients. These patients with persistent vestibular dysfunction were more likely to have persistent head-shaking nystagmus. Twelve (27.3%) of the 44 GCA patients had hearing improvement after 3 months of therapy. After 6 months of therapy, only 1 of the 44 GCA patients had abnormal vestibular tests. However, no additional improvement in hearing function was observed. The present study confirms a high frequency of audiovestibular manifestations in GCA. It also suggests that audiovestibular damage may be reversible in some patients with GCA.