The case report "Insomnia cycling with a 42-day infradian period: evidence for two uncoupled circadian oscillators?" by the Bologna group of Vignatelli et al. [1] in this issue of Sleep Medicine is fascinating in its own right, but also serves to expand our insomnia horizons. The beauty of this study lies in the meticulous collection of large amounts of behavioral and physiological data over an extraordinarily protracted time period (293 days encompassing seven periods of insomnia lasting 5-7 days). The authors conclude that the 42-day modulation of the amplitude of sleep duration in the patient reported could be explained by "beats" of two uncoupled oscillators with slightly different oscillating frequencies: (1) a "normal" circadian oscillator entrained to the external 24-h light/dark cycle, and (2) a "pathological" oscillator dominated by an endogenous stimulus with a period slightly differing from the 24-h light/dark cycle and insensitive to the external stimulus. Although there were no frank affective accompaniments of the alternating insomnia/hypersomnia, the response to valproate-a standard primary therapy of bipolar (affective) disorder (BD)-suggests .the possibility of an underlying BD [2].
展开▼
