Acute Effects of 50 Hz, 100 μT Magnetic Field Exposure on Visual Duration Discrimination at Two Different Times of the Day

Nikolaos Kazantzis, John Podd, Craig Whittington

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7 Citations (Scopus)


A two-alternative, forced-choice visual duration discrimination task was used to examine the effect of an intermittent, 50 Hz, 100 μT magnetic field on accuracy at two different times of the day. A total of 59 female and 40 male subjects with an age range of 18 to 46 years were studied under both field-exposed and sham-exposed conditions. The subject's task was to decide which of two sequentially presented light flashes had the longer duration, percentage correct being the measure of performance. The data were gathered under double-blind conditions with sham and real exposure counterbalanced. Exposure to the magnetic field produced a small improvement in accuracy but only at the most difficult level of the task, with female subjects showing a larger improvement than males. The time of day at which the study was run had no effect on performance. Despite the relatively large number of subjects used and a relaxed alpha level (P = .3), the statistical power of the test to detect the observed effect was still only 0.71. Bioelectromagnetics 19:310-317, 1998.

Original languageEnglish
Pages (from-to)310-317
Number of pages8
Issue number5
Publication statusPublished - 1 Dec 1998
Externally publishedYes


  • Extremely low frequency
  • Human performance
  • Statistical power
  • Visual discrimination

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