Sleep spindle characteristics as a function of age.

The characteristics of sleep spindles as a function of age were studied with an automated analysis system. Five age groups (group 0, 3-5 years; I, 13 years; II, 25-34 years; III, 42-53 years; and IV, 67-79 years) were analyzed. Significant differences in spindle frequency were found between groups 0-I and II-III-IV. The frequency increased with increasing age. No age differences were found in spindle duration. Spindle amplitude reached a peak in the group I subjects, then decreased with increasing age.