A quantitative analysis of head-shaking nystagmus of peripheral vestibular origin

Is There an “Acquired Idiopathic Head-Shaking Nystagmus”?—A Discussion of Mechanisms and Clinical Implications Based on a Case Report

Background

Head-shaking nystagmus (HSN) occurs in both peripheral and central vestibular disorders. In most cases, HSN can be attributed to an asymmetric peripheral vestibular input or a structural lesion mostly in the cerebellum affecting the central velocity storage mechanism. An isolated HSN is very rare.

Case Presentation

We report on a young female patient with the clinical picture of recurrent episodes of vertigo, which were induced by fast head movements and were accompanied by a severe right-beating HSN with a long time constant of 60 s. There was no other clinical and instrument-based evidence of peripheral vestibular dysfunction (including video head impulse test, caloric test, vestibular-evoked myogenic potentials) or indication of a structural lesion in the nodulus, uvula or pontomedullary brainstem on fine-slice magnetic resonance imaging. She had no previous history of migraine, hearing deficits, or other focal neurological symptoms. Diagnostic criteria for vestibular paroxysmia, vestibular migraine, benign peripheral paroxysmal vertigo, or any other known vestibular disorders were not fulfilled. Chart review in the database of the German Center for Vertigo and Balance Disorders indicated eight additional patients with a similar clinical phenotype between 2018 and 2022.

Conclusion

We propose a clinical entity called acquired idiopathic head shaking nystagmus (aiHSN) as a rare cause of episodic vertigo induced by fast head movements. Nystagmus characteristics suggest a subtle functional pathology of the central velocity storage mechanism in the nodulus and uvula, which is exacerbated during symptomatic episodes.

Head-Shaking Nystagmus in the Early Stage of Unilateral Meniere's Disease

OBJECTIVES

The aim of the present study was to evaluate the ability of head-shaking nystagmus (HSNy), evoked after the resolution of a vertigo spell, to predict an imminent crisis in the early stage of Meniere's disease (MD).

MATERIALS AND METHODS

A total of 20 patients in the early stage of MD were included in the study. The head-shaking test (HST) was performed twice, during the first visit within 24 h of vertigo spell (T0) and 48 h later (T1). The onset of a new vertigo episode during the 2 weeks following the first visit was recorded in each patient's medical record. The sensitivity and specificity of HSNy toward predicting a new vertigo episode were calculated.

RESULTS

At T0, an evoked ipsilesional HSNy in 15 (75%) patients was observed; in four of them, the HSNy had a biphasic component. The HSNy was present and persistent at T1 in 8 (42.1%) patients; among these cases, 6 patients had ipsilesional HSNy, and 2 patients a contralesional HSNy. None of the patients presented with a biphasic HSNy at T1. Seven (36.8%) patients experienced the recurrence of a vertigo crisis. Among these, 6 patients had ipsilesional HSNy at T1. Only 8 patients with ipsilesional HSNy at T0 did not have recurrence. The sensitivity of the ipsilesional HSNy in predicting the recurrence of vertigo in patients with MD was 100% at T0 and 85.7% at T1. The specificity was 46.6% and 100% at T0 and T1, respectively.

CONCLUSION

The HST can be a useful test in the early stages of MD to predict a new vertigo attack.

Recurrent spontaneous vertigo with interictal headshaking nystagmus

Objective

To define a disorder characterized by recurrent spontaneous vertigo (RSV) of unknown etiology and interictal headshaking nystagmus (HSN).

Methods

We characterized HSN in 35 patients with RSV-HSN compared to that recorded in randomly selected patients with compensated vestibular neuritis (VN), vestibular migraine (VM), and Ménière disease (MD).

Results

The estimated time constant (TC) of the primary phase of HSN was 12 seconds (95% confidence interval [CI] 12–13) in patients with RSV-HSN, which was larger than those in patients with VN (5 seconds, 95% CI 4–5), VM (5 seconds, 95% CI 5–6), or MD (6 seconds, 95% CI 5–6). TCs of the horizontal vestibulo-ocular reflex were also larger during the rotatory chair test in patients with RSV-HSN. Among the 35 patients with RSV-HSN, 7 showed vigorous long-lasting HSN with a peak slow-phase velocity >50.0°/s. In 5 patients (5 of 7, 71%) with vigorous HSN, HSN could have been induced even with headshaking for only 2 to 5 seconds. Long-term prognosis was favorable, with a resolution or improvement of the symptoms in more than half of the patients during the median follow-up of 12 (range 2–58) years from symptom onset. None developed VM, MD, or cerebellar dysfunction during the follow-up.

Conclusion

The clinical features and characteristics of HSN in our patients indicate a hyperactive and asymmetric velocity-storage mechanism that gives rise to intermittent attacks of spontaneous vertigo probably when marginal compensation of underlying pathology is disrupted by endogenous or exogenous factors.

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.

[Diagnostic value of head-shaking nystagmus in vestibular clinical evaluation]

OBJECTIVES

To determine the sensitivity and specificity of the head-shaking nystagmus test (HSN), the nystagmus elicited in response to a vigorous rotation of the head in the horizontal plane, in the study of patients with peripheral unilateral vestibular disease.

PATIENTS AND METHODS

Retrospectively, we analyze the relationships between the HSN and the rest of the videonystagmographic tests on eighty-three patients with peripheral unilateral vestibular disease.

RESULTS

Twenty-three patients showed a positive head-shaking nystagmus; twenty-one of them had unilateral caloric hypofunction and only two had a symmetric caloric test, but both of them showed some type of vestibular dysfunction on other videonystagmographic test. In our series, the HSN sensitivity for the existence of peripheral vestibular disease was 48.8%, while the specificity was 95% in relation to the caloric test, reaching 100% when the gold standard was the presence of any abnormal videonystagmographic test.

CONCLUSION

HSN is a simple test that can be useful to identify patients having unilateral vestibular hypofunction.

Functional significance of peripheral head-shaking nystagmus

OBJECTIVES/HYPOTHESIS

The objective was to determine the characteristics of horizontal head-shaking nystagmus of peripheral origin and its relationship to vestibular dysfunction.

STUDY DESIGN

Retrospective case series.

METHODS

Eighty-three patients met the inclusion criteria of having peripheral and unilateral vestibular disease. Patients were tested with video nystagmography. Head-shaking nystagmus was performed in the horizontal plane during 30 cycles at a frequency of approximately 3 Hz. Head-shaking nystagmus was classified as monophasic or biphasic and, based on the pathological ear, as ipsilateral or contralateral related to nystagmus fast phases. The two-tailed t test, ANOVA, Mann-Whitney and chi2 tests, and lineal and polynomial regression tests were used for statistical analysis.

RESULTS

Twenty-three patients showed a positive head-shaking nystagmus. All cases of head-shaking nystagmus observed were horizontal. There were four biphasic and 19 monophasic cases of head-shaking nystagmus. First phases of biphasic head-shaking nystagmus beat toward the normal ear. Eleven of the monophasic cases of head-shaking nystagmus were ipsilateral, and nine were contralateral. There was a statistically significant correlation between caloric weakness and head-shaking nystagmus. Ipsilateral head-shaking nystagmus corresponded to lower caloric asymmetries, and contralateral and biphasic head-shaking nystagmus corresponded to greater caloric weakness (P <.001). As the caloric asymmetry increased, the maximal slow-phase eye velocity of head-shaking nystagmus was greater (P =.01) and its duration shortened (P =.008). Ipsilateral responses could be distinguished from contralateral responses based on their latency (P =.03), maximal slow-phase eye velocity (P <.05), and duration (P =.02). The frequency of head-shaking nystagmus was significantly higher among older patients. There was no correlation between head-shaking nystagmus and clinical patterns.

CONCLUSION

Head-shaking nystagmus of peripheral vestibular origin is a response both qualitatively and quantitatively associated with the degree of the vestibular loss.

Head shaking nystagmus in the follow-up of patients with vestibular diseases

We examined 420 patients with vestibular diseases of different origin; 273 with peripheral vestibular disease and 147 with both peripheral and central vestibular disease. Recurrent vestibulopathy like Menière's disease, or benign paroxysmal positional vertigo, were not included. Patients were evaluated initially and 6 months after pharmacological and/or rehabilitation therapy. At the initial assessment, the head-shaking test was specific for the side of the lesion in both groups, even if spontaneous nystagmus was no longer present. Thus, head-shaking nystagmus is a physical sign that can be easily evoked and gives useful information about the presence of vestibulo-ocular reflex asymmetry. At the follow-up at 6 months, many changes in the head-shaking nystagmus were noted: in some cases it appeared, in some others it changed direction and more often it disappeared. There is actually no acceptable explanation for the disappearance of the head-shaking nystagmus, despite some evidence that vestibular compensation could play a role. It is definitely proved that sensitivity of the head-shaking test is really poor, especially in the course of time and, therefore, it should not be used alone in the follow-up of patients with vestibular disease.