Nystagmus as a sign of labyrinthine disorders--three-dimensional analysis of nystagmus

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.

Brainstem injury associated with supratentorial lesions is revealed by electronystagmography of the cold caloric reflex test

To explore the brainstem injury associated with supratentorial lesions, we conducted analysis of ICP levels and detected ENG parameters by using the cold caloric reflex test and histopathological examinations of the brainstem. Rat model of intracerebral hemorrhage was well-established in the study of supratentorial lesions of varying severities (n=210). Intracerebral pressure monitoring and electronystagmography of the cold caloric reflex test were simultaneously performed in animals. Apoptotic, immunohistochemical, and histopathological changes in different segments of the brainstem were investigated at various time intervals. Electronystagmography parameters were analyzed by cold caloric reflex test. The result showed that the increase of intracerebral pressure was correlated with lesion severity including elevating levels and rostral-caudal progression of neuronal apoptosis, demyelination, N-methyl-D-aspartate cell receptor down-regulation (r=0.815), and histopathological changes. Mutiple discrimination analysis of electronystagmography parameters presented a diagnostic accuracy rate of 79.5% in localizing brainstem injury. In conclusion, our data demonstrated that electronystagmography monitoring along with the cold caloric reflex test performed a favorable effect on the estimation of brainstem injury in ICH rat model, which provided a potential bedside diagnostic tool to assess and predict the progress of supratentorial lesion patient in future.