CRISP: sleep state scoring in human infants

Abstract

In contrast to those interested in adult sleep, researchers interested in infant sleep are concerned with age-related changes in the organization of sleep states as well as with the rhythm of REM-nonREM cycles, During the newborn period, for example, organization is incomplete; the physiological and behavioral activities recorded during sleep are not readily classified into two distinct sleep states (such as REM and nonREM) because of a large amount of sleep which appears poorly organized and has mixed features. An infant sleep scoring manual was published in 1971 which resulted from an international collaborative effort to standardize terms and techniques (Anders, Emde, & Parmelee, 1971), This manual defincd three sleep states: Active REM sleep, quiet sleep, and indeterminatc sleep. Active REM sleep and quiet sleep were clearly distinguishable by multiple criteria and were considered precursors of REM and nonREM sleep in the older child and adult. On the other hand, indeterminate sleep was poorly organized with mixed features and was considered an immature state, most characteristic of prematures and young fullterms. Indeterminate sleep was also cunsidered characteristic of some abnormal infants. CRISP is a computer program which autumatically categorizes infant sleep using the infant sleep manual standards for coding parameters of EOG, EEG. EMG, respiration. and body movement. Multiple critcria for active REM sleep include presence of eye movements. a nat or mixed EEG, a low amplitude EMG. irregular respirations, and the presence of body movement. Multiple criteria for quiet sleep include the absence of eye movements, a high voltage or trace alternant or mixed EEG, a high amplitude EMG. regular respirations, and the absence of body movements. The CRISP system is an adaptation and extension of Anders' RIPVAN program for use on smaller PDP- I 2 laboratory computers (Anders & Zangen, 1972).