The intensity of downbeat nystagmus during daytime

Rainer Spiegel, Nicole Rettinger, Roger Kalla, Nadine Lehnen, Dominik Straumann, Thomas Brandt, Stefan Glasauer, Michael Strupp

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

18 Scopus citations

Abstract

On the basis of reports by patients with downbeat nystagmus (DBN) that their symptoms were worse during the morning but better during the daytime, we investigated whether the intensity of DBN changes during the daytime. DBN was measured at 9 am, 11 am, and 1 pm. The mean peak slow phase velocity (MPSPV) of DBN was determined in different eye positions, with and without fixation, as well as in three different body positions: sitting upright, lying supine with the nose up, and lying prone with the nose down. Twelve patients with DBN either due to cerebellar degeneration or of idiopathic etiology were examined. The major findings of this study were as follows. First, the intensity of DBN significantly decreased during the daytime. When measured in the sitting upright position and primary eye position, MPSPV decreased from 4.32 deg/sec (±SEM 1.02) at 9 am to 2.12 deg/sec (± 0.5) at 11 am (P < 0.01) and stayed constant around 1.93 deg/sec (± 0.57) at 1 pm (P < 0.01 from 9 am to 1 pm) and 2.08 deg/sec (± 0.75) at 3 pm (P < 0.01 from 9 am to 3 pm). Second, this change did not depend on fixation during the measurements. Third, this effect was not influenced by the eye position during the measurements (upward, downward, or straight ahead). Our data show that the intensity of DBN decreases during the daytime. This decrease correlates with the symptoms of the patients. This change during daytime did not depend on visual fixation. Another possible mechanism is the modulation of DBN by head position relative to gravity, that is, by otolith input. This should be evaluated in further studies.

Original languageEnglish
Title of host publicationBasic and Clinical Aspects of Vertigo and Dizziness
PublisherBlackwell Publishing Inc.
Pages293-299
Number of pages7
ISBN (Print)9781573317177
DOIs
StatePublished - May 2009
Externally publishedYes

Publication series

NameAnnals of the New York Academy of Sciences
Volume1164
ISSN (Print)0077-8923
ISSN (Electronic)1749-6632

Keywords

  • Daytime improvement
  • Downbeat Nystagmus (DBN)
  • Gaze direction
  • Head position
  • Slow phase velocity

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