The nystagmus of vestibular paroxysmia

Cross-Sectional Analysis of Videonystagmography (VNG) Findings in Balance Disorders

OBJECTIVE

To understand the videonystagmography (VNG) findings in various balance disorders in 67 patients who presented to the outpatient department of an otorhinolaryngology clinic.

MATERIALS AND METHODS

This cross-sectional study was conducted in the outpatient department of the otorhinolaryngology clinic of a tertiary care center. A total of 67 patients between the age group of 18 and 70 years with balance disorders were included in the study. VNG findings in different balance disorders were observed and analyzed.

RESULTS

A total of 67 patients were enrolled in the study. Findings like caloric inversion and optokinetic nystagmus do not always indicate a central balance disorder due to technical errors and other limitations during the test. However, abnormal saccades seem to be a more relevant finding in central disorders. Rare variants of benign paroxysmal positional vertigo (BPPV) like multiple canal BPPV were also diagnosed using VNG.

CONCLUSION

VNG has come out as a very useful test in our study aiding in 75% of diagnoses. The overall benefits of VNG in balance disorders are immense and necessitate their inclusion in every vertigo clinic.

A dynamical method to objectively assess infantile nystagmus based on eye tracking. A pilot study

PURPOSE

The purpose of this research is to propose a new method for the easy, inexpensive and objective quantification of nystagmus using eye-tracking records collected during a simple reading task that could be implantable in clinical practice to assess patients with nystagmus.

METHODS

This is a prospective, observational pilot study. Eye movements of 4 nystagmus patients and 9 healthy children during a reading task (a paragraph with 82 words) on a 15'' monitor were collected and compared. Data are time series indicating the gaze position on the screen. Two quantifiers were proposed: IndS (based on the speed of movements) and IndF (based on the variation of the gaze trajectory).

RESULTS

The indices proposed reflect differences in the behavior of eye movements between the two groups. Nystagmus patients present higher values of IndS - indicating smaller number of slow movements (16% of movements with speeds <0.33 1/s for nystagmus and 85% for the control group, with p = 0.01) - and higher values of IndF - indicating higher gaze fluctuation (p = 0.01). Differences were not related with reading speed as show the mean and standard deviation: the nystagmus group required 115±45 s to complete the task and the control group 151±85 s; p = 0.73.

CONCLUSIONS

The proposed indices provide a new method that allows an objective assessment of nystagmus, with potential use in clinical and research practice to improve the follow-up of patients by monitoring the nystagmus over time or treatment.

Direction-changing spontaneous nystagmus in patients with dizziness

PURPOSE

The present study aimed to investigate the clinical features of patients with direction-changing spontaneous nystagmus (DCSN) and gain insight into its underlying mechanisms.

METHODS

Medical records and vestibular function test results collected in our dizziness clinic between February 2013 and February 2020 were retrospectively reviewed. Spontaneous nystagmus was recorded while sitting upright using videonystagmography for 2 min to confirm the spontaneous changes in nystagmus direction. Causative disease diagnoses were based on the patients' clinical history, audiometry results, vestibular function tests, and imaging studies.

RESULTS

Of 4786 patients, DCSN was observed in 41 (0.86%). Causative disease diagnoses included vestibular neuritis (n = 9), lateral semicircular canal cupulopathy (n = 9), cerebellopontine angle tumor (n = 8), vestibular paroxysmia (n = 2), vestibular migraine (n = 2), vestibular nucleus infarction (n = 1), sudden sensorineural hearing loss with vertigo (n = 2), Meniere's disease (n = 2), Ramsay Hunt syndrome (n = 1), labyrinthine fistula due to middle ear cholesteatoma (n = 1), lateral semicircular canal dysplasia (n = 1), post tympanomastoidectomy dizziness (n = 1), and head trauma (n = 2).

CONCLUSIONS

Although the periodicity of DCSN could not be determined because of insufficiently long observation times, it was observed in various central and peripheral vestibulopathies. Careful examination of spontaneous nystagmus over a sufficient period may ensure the detection of DCSN when evaluating dizziness.

Application of ABR in pathogenic neurovascular compression of the 8th cranial nerve in vestibular paroxysmia

PURPOSE

To investigate the clinical value of electrophysiological tests in indicating pathogenic vascular contact of the 8th nerve in definite vestibular paroxysmia (VP) cases to provide a reference for decompression surgery.

METHODS

We retrospectively analyzed patients who had vertigo, unilateral tinnitus, or hearing loss and exhibited vascular contact of the 8th cranial nerve by MRI. Participants were classified into the VP or non-VP group according to the criteria of the Bárány Society in 2016. The demographic characteristics and audiological and electrophysiological test results of the two groups were compared. Receiver operating characteristic (ROC) curves were calculated for ABR to determine the best parameters and cutoff values to predict the existence of pathological neurovascular contact in VP.

RESULTS

Thirteen patients in the VP group and 66 patients in the non-VP group were included. VP patients had longer interpeak latency (IPL) I-III and wave III latency compared to non-VP patients (p < 0.001; p < 0.001). According to the ROC analyses, IPL I-III and wave III latency were the best indicators for the diagnosis of VP. The optimal cutoff for IPL I-III was 2.3 ms (sensitivity 84.6%, specificity 95.5%), and that for wave III latency was 4.0 ms (sensitivity 92.3%, specificity 77.3%). There were no differences in the PTA, caloric test, o-VEMP, or c-VEMP results between the two groups.

CONCLUSION

Prolonged IPL I-III and the wave III latency of ABR strongly suggested that vascular contact of the 8th cranial nerve was pathological, which may provide some references for microvascular decompression surgery of VP.

Direction-changing spontaneous nystagmus in cerebellopontine angle tumour

The most common symptoms of tumours involving the cerebellopontine angle (CPA) are unilateral sensorineural hearing loss, dizziness, and asymmetric tinnitus. While the clinical manifestations have been well documented in previous studies, the nystagmus findings in these patients have not been thoroughly investigated yet. This study aimed to investigate the incidence of direction-changing spontaneous nystagmus in patients with CPA tumours, evaluate their radiologic characteristics, and gain insight into the mechanisms underlying nystagmus. Direction-changing spontaneous nystagmus was observed in 6 out of 83 patients (7%) with CPA tumours during the 7-year period. Temporal bone magnetic resonance imaging findings revealed the presence of an intrameatal mass in CPA tumours in all six patients with direction-changing spontaneous nystagmus. Vestibular schwannomas were confined within the internal auditory meatus in four patients, and petroclival meningiomas extended into the internal auditory meatus in two patients. The mechanism of direction-changing spontaneous nystagmus may be explained as paroxysmal secondary central hyperactivity in the vestibular nucleus due to the long-standing pressure effect in the vestibular nerve by tumours, or by ephaptic discharges in the vestibular nerve.

Vestibular paroxysmia caused by contralateral tortuous vertebral artery: A case report

RATIONALE

Vestibular paroxysmia (VP) is characterized by spontaneous, recurrent, short, paroxysmal attacks of vertigo with or without tinnitus.

PATIENT CONCERNS

We report a case of paroxysmal recurrent vertigo accompanying clicking tinnitus on the left side in a 61-year-old patient. He had undergone microvascular decompression to treat the left-side hemifacial spasm 6 years prior. The patient first developed vertigo attacks about 3 years after microvascular decompression, and the attacks increased in frequency over the last 4 months. Video-nystagmography revealed a background right-beating nystagmus which was reversed every 55 seconds, to left-beating nystagmus for 17 seconds.

DIAGNOSIS

Brain magnetic resonance imaging and angiography demonstrated a compression of the cisternal segment of the left vestibulocochlear nerve between the tortuous right vertebral artery and the posterior wall of the left porus acusticus internus.

INTERVENTIONS AND OUTCOMES

Under the diagnosis of VP, 300 mg oxcarbazepine was administered daily, which relieved the symptoms dramatically.

LESSON

The neurovascular cross-compression of the vestibulocochlear nerve by the contralateral vertebral artery tortuosity can cause VP. Periodic paroxysms of right-beating nystagmus accompanying the left-side tinnitus during vertigo attacks in our patient can be explained by secondary central hyperactivity in both vestibular and cochlear nuclei following long-standing neurovascular cross-compression.