What happens to spontaneous nystagmus during sleep in patients with acute unilateral vestibulopathy?

Introduction It is known that spontaneous nystagmus (SPN) in patients with acute unilateral vestibulopathy (AUV) can be suppressed by narcosis or medication. It is less well known if or how an SPN changes during sleep. The aim of this study was therefore to analyze the SPN during sleep in patients with AUV.

Methods According to the standards of the American Academy of Sleep Medicine (AASM), cardio-respiratory polysomnography (PSG) and electronystagmography (ENG) were performed in all 17 patients, with AUV and a horizontally beating SPN. The frequency and amplitude of nystagmus were analyzed during sleep phases and compared with waking state.

Results At all 17 patients, a medium-frequency horizontal beating SPN was observed with 1.5-4 beats/second when the patients were awake. With the decrease of alpha and beta activity in the electroencephalography, the amplitude of the SPN also decreased significantly with no change in frequency (p> 0.05). In the further course of the recording, the frequency of the SPN also decreased significantly in all patients (p> 0.05). On average, about one minute before reaching sleep phase N1 the SPN could no longer be detected. When arousles appeared in sleep phases N1, N2 or N3, the SPN showed the same frequency and amplitude as when the patients were awake.

Conclusion We could show that even before reaching sleep phase N1 the SPN is completely suppressed in patients with AUV. We presume that central vestibular structures influence this deprivation, and additionally supranuclear structures were involved.

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Publication History

Article published online:
10 June 2020