Recovery Phase Spontaneous Nystagmus, Its Existence and Clinical Implication

BACKGROUND AND OBJECTIVES: Determination of the lesion side based on the direction of the nystagmus could result in confusions to the clinicians due to mismatch between the vestibular function tests and also between vestibular and audiologic features. To minimize these mistakes, we elucidated the clinical manifestation and vestibular function test results in cases with recovery spontaneous nystagmus (rSN). SUBJECTS AND METHODS: Patients who visited ENT clinic of tertiary referral hospital for acute onset continuous vertigo from January 2008 to December 2011 were enrolled. In these patients, we assessed onset time of vertigo, time point of paralytic spontaneous nystagmus (SN) and time point of rSN. At each time point of SN, vestibular function tests and hearing function tests were performed. RESULTS: We confirmed the rSN among patients with unilateral vestibulopathy and demonstrated that high gain of the rotatory chair test (slow harmonic acceleration) and/or mismatch of the SN direction and contralateral caloric weakness could indicate the recovery state of patients and nystagmus observed in this stage is recovery phase nystagmus. CONCLUSIONS: In acute vestibulopathy patients, recovery phase nystagmus was observed and on this stage of disease vestibular function tests shows several features that could predict recovery state.

The Clinical Efficacy of Vestibular Function Tests in Patients with Acute Unilateral Vestibulopathy / 대한평형의학회지

OBJECTIVES: Aim of this study is to investigate the clinical efficacy of the vestibular function tests (VFTs) and the predictability of lesion side of vestibular asymmetry parameters in acute unilateral peripheral vestibulopathy. METHODS: Medical records and results of VFTs (caloric, rotatory chair, and head impulse tests) of 57 patients with acute unilateral vestibulopathy were reviewed retrospectively. The VFTs were examined within 7 days after the clinical onset. RESULTS: For the caloric test, 74% showed significant canal paresis and the predictability of lesion side was 88%. For the sinusoidal harmonic acceleration test, 91% had low gain in at least 1 Hz, phase lead showed 70%, 89% showed phase asymmetry and the predictability of lesion side was 90%. For velocity step test, 67% had abnormal Tc asymmetry and the predictability of lesion side was 95%. In bedside head impulse test (HIT), abnormal catch up saccades were observed in 89% and the predictability of lesion side was 100%. For the video HIT, cover or overt catch-up saccades were observed in 95% and the predictability of lesion side was 100%. One hundred percent (100%) had low gain on the video HIT, but the lesion sides were uncertain because of bilateral involvements or artifacts. CONCLUSIONS: The most important things in the diagnosis of acute unilateral vestibulopathy are typical clinical symptoms and spontaneous nystagmus. A combination of rotatory, caloric, and HITs will result in a more complete examination of the vestibular system. Among them, HIT is recommended as the best tool in acute unilateral vestibulopathy.

Mastoid Vibration Reduces Ipsilesional Shift of Subjective Visual Horizontal in Patients with Acute Stage of Unilateral Vestibulopathy

BACKGROUND AND OBJECTIVES: To investigate effect of the vibration on subjective visual horizontal (SVH) in patients with acute stage of unilateral vestibulopathy. SUBJECTS AND METHODS: Twenty-five unilateral vestibulopathy patients which analyzed into 42 cases at different time points and suffered from spinning vertigo for more than 24 hours without hearing loss and neurologic abnormality were enrolled. Thirteen subjects with spontaneous nystagmus (>3 degree/sec; averaged symptom onset <1 week) at the time of SVH measurement were classified into the acute unilateral vestibulopathy group (aVU). The other 29 subjects without spontaneous nystagmus were classified into the compensated vestibulopathy group (cVU). SVH was performed with vibration at either mastoid or sterocleidomastoid muscle. RESULTS: In the analysis of overall subjects, vibration did not significantly change the degree of shift of SVH. However, analyzed by group, the shift of SVH with vibration at ipsilesional mastoid was significantly decreased than baseline in aVU (p<0.05). The shift of SVH with vibration at contralesional mastoid was significantly increased than baseline in cVU (p=0.05). CONCLUSIONS: The shift of SVH due to vibration in acute stage of unilateral vestibulopathy showed reduction of the shift, while in compensated stage it showed increase of the shift.

Predictive Value of Rectified Vestibular Evoked Myogenic Potential in Determining Lesion Side in Unilateral Vestibulopathy Patients / 대한평형의학회지

BACKGROUND AND OBJECTIVES: Rectified vestibular evoked myogenic potential (rVEMP) is a relatively new method that simultaneously measures the muscle contraction power during VEMP recording and corrects the difference of contraction power afterwards. Several studies showed rVEMP is more reliable than non-rectified VEMP (nVEMP). However, those studies evaluated usefulness of rVEMP in patients with normal vestibular function. Thus, we evaluate the effect of rectification to predict lesion side in unilateral vestibulopathy patients. MATERIALS AND METHODS: One-hundred nine acute unilateral vestibulopathy patients whom VEMP were performed in were included retrospectively. We regarded hearing loss side as lesion side in sudden hearing loss (n=33), meniere's disease (n=29) and in vestibular neuritis (n=45), the side of positive head thrust test with canal paresis >30% was regarded as a lesion side. We excluded bilateral vestibulopathy. The inter-aural amplitude difference (IAD) ratio was calculated by the nVEMP and rVEMP. RESULTS: Mismatch rate between nVEMP and rVEMP was 36.61%, match rate was 49.54%, opposition rate was 13.76%. rVEMP predicted lesion side on 15 patients of mismatch group correctly, while nVEMP predicted lesion side on 25 patients of mismatch group. There was no significant difference in IAD ratio between nVEMP and rVEMP in patients who showed lesion side weakness on both nVEMP and rVEMP. But, the younger the patient was, the more chance of mismatch was significantly (p=0.03). CONCLUSION: There was no more corrective role in determining lesion side by rectification in unilateral vestibulopathy. Thus rVEMP might not be helpful for predicting lesion side in unilateral vestibulopathy.

A Case of Isolated Cerebellar Nodulus Infarction with Periodic Alternating Nystagmus and Unilateral Vestibulopathy

We report a patient with an isolated cerebellar nodulus infarction who presented with periodic alternating nystagmus (PAN), perverted head-shaking nystagmus (pHSN), and loss of tilt suppression of the vestibulo-ocular reflex (VOR). Several days after the initial symptoms resolved, the patient also presented with purely vestibular syndrome with vertigo, spontaneous horizontal nystagmus without the usual signs of cerebellar dysfunction. The chain of those symptoms were ascribed to ischemia of the cerebellar nodulus.