Dreams recall and auditory evoked potentials during propofol anaesthesia

Abstract

It is unclear whether shorter wave latencies of middle-latency-auditory-evoked-potentials may be associated to cognitive function other than nondeclarative memory. We investigated the presence of declarative, nondeclarative and dreaming memory in propofol-anaesthetized patients and any relationship to intraoperatively registered middle-latency-auditory-evoked-potentials. An audiotape containing one of two stories was presented to patients during anaesthesia. Patients were interviewed on dream recall immediately upon emergence from anaesthesia. Declarative and nondeclarative memories for intraoperative listening were assessed 24 h after awakening without pointing out positive findings. Six patients who reported dream recall showed an intraoperative Pa latency less than that of patients who were unable to remember any dreams (P<0.001). A high responsiveness degree of primary cortex was associated to dream recall formation during anaesthesia.

Dreaming and awareness during dexmedetomidine- and propofol-induced unresponsiveness

“…10 In previous studies, dreams reported after anaesthesia are usually pleasant, short, simple, related to everyday life, and unrelated to the operative setting. 10,13,22,23 Our findings partially corroborate previous results as the dream reports were brief, only a quarter of the dream experiences were dynamic, and positive emotional states were slightly more frequent than negative emotional experiences.…”

Stress-related biomarkers of dream recall and implicit memory under anaesthesia

“…When the patients opened their eyes at the end of anaesthesia, they were immediately asked whether they recalled any dreams, and if so, were requested to describe the details. Approximately 24 h after surgery, patients were asked a series of open‐ended questions to probe explicit recollection of intra‐operative events : ‘What is the last thing you remember before falling asleep?’, ‘What is the first thing you remember upon awakening?’, ‘Did you dream while you were asleep?’, ‘Did you hear any words or sounds while you were asleep?’ Implicit memory was investigated using a story‐related free association test .…”

“…Incomplete abolition of cognitive faculties such as memory and learning during anaesthesia has been studied for many years . Interestingly, in most cases anaesthetic drugs cause obliteration of explicit memory, whereas implicit memory and/or dream recall may sometimes be preserved . Previous studies have tried to identify the relationship between implicit memory or dream recall and depth of anaesthesia using EEG‐derived parameters .…”

“…Interestingly, in most cases anaesthetic drugs cause obliteration of explicit memory, whereas implicit memory and/or dream recall may sometimes be preserved . Previous studies have tried to identify the relationship between implicit memory or dream recall and depth of anaesthesia using EEG‐derived parameters . In this respect, both implicit memory and dream recall have been associated with a high degree of responsiveness of the primary cortex .…”

“…Previous studies have tried to identify the relationship between implicit memory or dream recall and depth of anaesthesia using EEG‐derived parameters . In this respect, both implicit memory and dream recall have been associated with a high degree of responsiveness of the primary cortex . Another area of interest is to identify possible intra‐operative factors responsible for memory formation under anaesthesia.…”