Nature of sleep in young infants

¹ Institute for the Care of Mother and Child, Prague, Czechoslovakia

Using criteria of ocular reactions, bodily activity, and respiration in 12 infants up to 6 months of age, four stages of the waking and the sleeping state have been distinguished: 1) deep sleep, as judged by closed eyes, virtual disappearance of bodily activity, regular respiration, and lowered frequency of breathing; 2) sleep with closed eyes, but greater bodily activity and irregularity of respiration; 3) light sleep, or the transitional state between sleep and waking as manifested by alternating open, closed, and half-open eyes, increased activity and frequency of breathing, and irregularity of respiration; 4) the waking state with open eyes, great bodily activity and respiratory frequency, and irregular respiration. This differentiation has enabled more accurate modification of the usually reported observations concerning the shortening of sleep in early life. It is not the duration of deep sleep which decreases, but rather the transitional state between sleep and waking. The waking state significantly lengthens with age.

Note:
(With the Technical Assistance of V. Lapáková)