Abstract
Congenital nystagmus (CN) is a disorder of the ocular motility characterized by oscillatory eye movements preventing the correct fixation of a target. Many typical waveforms of eye position recordings have been recognized and classified in the literature: in jerk CN a slow phase eye movement is followed by a fast phase, giving rise to a typical saw-tooth waveform, while in pendular CN the eyes exhibit a periodic motion, giving rise to an approximately sinusoidal waveform. Dual jerk waveforms seemed to show small, rapid oscillations superimposed on a jerk-like waveform, thus being originary classified as a mixture of jerk and pendular CN. On the contrary, a theoretical model of CN has appeared recently, which suggests a possible interpretation of the small amplitude oscillations in dual jerk waveforms as consecutive pieces of growing and decaying exponentials.
By spectral analysis of dual jerk waveforms in a number of patients with CN, we show that the oscillations are truly sinusoidal in nature, thus suggesting the possibility of a different explanation of dual jerk waveforms in CN.
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Reccia, R., Roberti, G., Russo, P. et al. Spectral analysis of dual jerk waveforms in congenital nystagmus. Biol. Cybern. 55, 211–217 (1986). https://doi.org/10.1007/BF00355596
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DOI: https://doi.org/10.1007/BF00355596