Four blind individuals who were thought to be entrained at an abnormal circadian phase position were reset to a more normal phase using exogenous melatonin administration. In one instance, circadian phase was shifted later. A fifth subject who was thought to be entrained was monitored over four years and eventually was shown to have a circadian period different from 24h. These findings have implications for treating circadian phase abnormalities in the blind, for distinguishing between abnormally entrained and free-running blind individuals, and for informing the debate over zeitgeber hierarchy in humans.
- Circadian rhythms
- Melatonin phase response curve
- Totally blind people
ASJC Scopus subject areas
- Physiology (medical)