Memory Priming in General Anesthesia
Condition: Unconscious (Psychology)
MeSH terms: Unconsciousness
Study type: Interventional

Summary: 
      Memory priming under general anesthesia is a phenomenon of incredible interest in the study
      of consciousness and unconscious cognitive processing, and for clinical practice.

      However results from anesthesiological literature are divergent and methodologies vary.

      To overcome these limits, the present study aims at better defining the phenomenon of memory
      priming under general anesthesia, manipulating as experimental variables both the anesthetic
      drug used and the stimuli primed.
    

Detailed description: 
      Some patients may develop serious psychological sequelae after surgical intervention under
      general anesthesia due to implicit memory formation of intraoperative events.

      A number of studies in the field of anesthesiology have tried to better define the phenomenon
      of implicit memory in general anesthesia, with conflicting results. While some studies
      demonstrated the existence of unconscious memory formation also under adequate general
      anesthesia (BIS ranging 40-60), others state that implicit memory formation is possible only
      during light sedation, and that, therefore, traumatic disorders due to unconscious
      intraoperative memories are imputable to inadequate anesthesiological intraoperative
      management. The methodologies used by these studies, however, are very heterogeneous, and
      often inaccurate from a cognitive point of view. Data from cognitive neuroscience, in fact,
      demonstrate that different linguistic material, e.g. abstract and concrete words, are
      processed and retrieved via different networks in the brain. Then, since different
      anesthetics are known to target different areas of the brain, it is assumable that implicit
      memory formation is influenced both by the specific drug used and by the type of stimuli
      primed.

      Therefore in this experiment, the investigators aim at testing implicit memory for different
      word category, abstract vs. concrete words, in patients undergoing either propofol or
      sevoflurane general anesthesia. Also, a very strict methodology was used both for the
      construction of the stimuli and the stimulation and testing procedure, in order to maximize
      the priming effect and exclude the risk of false positive results. The investigators
      hypothesize that, considering the existing data on propofol and sevoflurane effects on the
      brain, and the known neural correlates for abstract and concrete word processing, the priming
      effect would be different for abstract and concrete words between patients under propofol or
      sevoflurane anesthesia.
    

Intervention name(s): Abstract priming; Concrete priming; Controls; Propofol; Sevoflurane
Intervention type(s): Behavioral; Behavioral; Behavioral; Drug; Drug
Intervention description(s): Patients were primed with a list of abstract during their general anesthesia; Patients were primed with a list of concrete during their general anesthesia; Patients did not receive any specific stimulation with words during their general anesthesia; Propofol general anesthesia; Sevoflurane general anesthesia
Intervention MeSH terms: Propofol; Sevoflurane
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Outcomes Assessor)
Primary purpose: Basic Science
Keywords: Memory priming; Anesthesia; Language processing; Abstract and Concrete words; Neural correlates