Discussion and re-analysis of experimental data in the investigation of ultradian rhythms in humans.

Abstract

In this paper a discussion and re-analysis of experimental data is carried out. The data consist of measurements of the performance on two tasks (verbal and spatial) that are performed by the two different brain halves. The original experiments and analysis had been conducted by R. Klein and R. Armitage in the investigation of ultradian rhythms in humans. The period of the ultradian cycle had been hypothetically equated to the period of REM-sleep occurrence. In the re-analysis, previously unmentioned inhomogeneity was discovered and the findings by the original experimenter-analysts could not be confirmed at the stated significance levels. A discussion of and recommendations for the experimental set-up are included. The re-analysis was conducted with non-parametric methods. Small ultradian rhythmicity was concluded to have been induced by influence of circadian rhythm, experimental set-up and inhomogeneity among subjects.