A PSYCHOPHYSIOLOGICAL STUDY OF NIGHTMARES AND NIGHT TERRORS: III.Mental Content And Recall of Stage 4 Night Terrors

Abstract

This report is concerned with a) the degree of recall of mental content from Stage 4 night terrors; b) the classification of the types of mental content recalled; c) the problem of whether the mental content recalled occurred just before, during, or after the explosive onset of the night terror episode, that is, whether it was related to “prearousal” or “postarousal” events; and d) the implications of the above findings for the problem of the nature of the triggering mechanism of the night terror. A mean of 58 per cent recall of mental content from night terrors was found, approximating that reported from elicited nonanxious Stage 3-4 awakenings in normal subjects. As inferred from subjects' reports, content was retrieved from all temporal phases of the night terror, both pre- and postarousal, and including in a few instances ongoing mental content during Stage 4 just prior to the sudden eruption of the episode. The fact that the night terror episode does not show a gradual buildup, either psychological or physiological, does not militate against the possible role of ongoing Stage 4 mentation in triggering it. Such mentation may touch upon an intense conflict area, producing a terrifying image or thought, suddenly igniting intense panic. The extensive screaming, cursing and sleeptalking of the night terror may be responses to preceding Stage 4 mental content, as indicated by numerous examples of concordance observed, that is, the mental content recalled closely resembles the sleep utterances that had occurred during the episode. Postarousal content may be elaborated in relation to autonomic response, e.g., fears of dying associated with pounding of the heart. Although the content of night terrors frequently consists of a single scene or thought, there were many reports of traumatic content unique and unusual, quite elaborate and dreamlike, sometimes consisting of one or more scenes in sequence, and very unlikely to have originated in the postarousal period in response to physiological sensation or environmental conditions. In some instances the subject reported that the frightening content caused him to scream and initiated the episode. Although there is a relatively high percentage of recall, memory for the events of the night terror is often fragmentary and there may be marked amnesia. For example, it is our impression that there is rarely recall of the extensive sleeptalking and screaming that usher in the night terror. Night terrors may be elicited artificially by sounding a buzzer and thisconstitutes the best evidence that mental activity need not be the only precipitating factor. The hypothesis is advanced that episodes may be triggered either by endogenous ongoing mental activity during Stage 4 sleep or exogenously in the form of loud noises or other external stimulation.