REM-dreams recall in patients with narcolepsy-cataplexy

Abstract

An abundant recall of dreams has been observed in clinical studies on patients with narcolepsy-cataplexy (NC), a neurological disorder characterized by an altered sleep architecture. Laboratory studies have shown that dream experiences developed during 1st-rapid eye movement (REM) sleep by NC patients are longer and more complex than those of healthy subjects. To establish whether these features indicate an earlier optimal functioning of the cognitive processes involved in dream generation rather than a more accurate dream recall, we compared the indicators of length and structural organization in reports of REM-dreams collected from 14 NC patients and their matched controls. During an experimental night two awakenings were provoked after 8 min in 1st- and 3rd-REM sleep; participants were asked to report their dream experience (spontaneous report) and then, if possible, further remembered parts of this experience (prompted report). All reports were analyzed using story-grammar rules, which allow us to identify units larger than single contents and describe their story-like organization. While dream recall (about 90%) was comparable in NC patients and controls, 1st-REM spontaneous reports were longer and more complex in NC patients, half of whom also provided prompted reports. After 3rd-REM awakening more than one third of NC patients and controls gave prompted reports, which were fairly comparable in length and complexity with the spontaneous reports. These findings confirm that the cognitive processes underlying dream generation reach their optimal functioning earlier in the night in NC patients than in normal subjects, and raises the question of whether the dream-stories described in spontaneous and prompted reports are part of the same or distinct REM-dreams.