TASK-INDUCED STRESS AND MOTIVATION DECREASE FOVEATION-PERIOD DURATIONS IN INFANTILE NYSTAGMUS SYNDROME
Kwang Meng Cham 1,
Andrew John Anderson 1,
and
Larry A. Abel 1*
1 Optometry & Vision Sciences, University of Melbourne, Carlton, Victoria, Australia
* To whom correspondence should be addressed. E-mail: label{at}unimelb.edu.au.
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Abstract |
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Purpose: To investigate the effect of visual demand, task-related physiological stress, and motivation on the nystagmus waveform of nineteen INS subjects. Methods: Subjects viewed a Landolt C of varying orientation and size, indicating its orientation via arrow keys on a keyboard. Mental arithmetic was carried out in conjunction with the visual task. Subjects then undertook a reward/penalty paradigm. Eye movements and heart rates were recorded for all experiments. Results: Task-related physiological stress and motivation were reflected in an increase in heart rate; they led to an increase in the amplitude, frequency and intensity of the nystagmus waveform, and decreased foveation-period durations. Changes in heart rate were uncorrelated with changes in waveform parameters for all experiments. Conclusions: We have shown for the first time the negative impact of task-induced stress and/or motivation upon the characteristics of INS. This has important implications for individuals with INS, since stress may arise in everyday situations, such as driving or when undertaking an exam.
Key Words:
eye movements, congenital nystagmus, neuroophthalmology, nystagmus, stress, motivation
