Written By Alexis Mitchell UNCC ‘18
An intrusive memory is a type of negative memory that is generally experienced through short, vivid sensory fragments such as: visual image, taste, smell, sound, or bodily sensation (Ehlers et al, 2002). Intrusive memories are an enigmatic aspect of posttraumatic stress disorder (PTSD) that researchers have sought to explain and clarify. These types of memories can be experienced by individuals with PTSD and perceived as some kind of threat in the present moment. Intrusions of this nature can be viewed as “warning signals.” Ehlers and colleagues hypothesize that intrusive memories for individuals with PTSD do not usually represent the most traumatic aspects of the traumatic experience, but rather contain auditory and visual intrusions that may be considered minor details (2002).
To test this hypothesis, they conducted four different studies with four different participant groups with individuals who had experienced road traffic accidents, childhood sexual abuse trauma, and ambulance service workers who experience trauma in their work. There were two groups for the category of road traffic accidents and one group for the each of the other two categories. One road traffic accident group had sixty-four percent of participants that met criteria for PTSD and forty-eight percent in the other group. Twenty-one percent of ambulance staff met the criteria and eighty-six percent of childhood sexual abuse participants also met criteria. All participants were pulled from participant pools of other research studies pertaining to PTSD and intrusive memories. In each of the four participant groups, participants were interviewed and asked to describe their typical intrusive memories of their specific traumatic event and to indicate what qualities the memories had.
The results from the interviews indicated that intrusive memories often consisted of stimuli that were present immediately before the traumatic event happened or shortly before the moments that had the largest emotional impact. For example, one woman participant who was raped in her home kept seeing the perpetrator standing inside her bedroom door as she had seen him when she woke up. If an individual was limited as far as visual input, i.e. getting attacked in a dark room and not being able to see clearly, auditory or other sensory impressions would be re-experienced, such as the sounds or smells during the time.
It is important to note that the moments with the largest emotional impact do not necessarily occur during the traumatic event itself, but may occur somewhat later when the patient realized what could have happened or when something gives the situation a more traumatic personal meaning. In addition, in prolonged trauma, there could be several moments of the memory that give a situation a more traumatic personal meaning.
In sum, the results from this research confirm the warning signal hypothesis. In such that, the intrusive memories often experienced by these patients were temporally associated with the traumatic event and can acquire the status of being a warning signal: stimuli that if encountered again, would surely indicate impending danger. Associative learning is a process that singles out stimuli with the highest information value in terms of temporal association, which is indicative of the emotional significance of the intrusion in association with the stimuli as perceived by the trauma survivor.
This research has the potential to help guide therapists to encourage patients to learn the discrimination between the “then” and the “now.” Simply, the stimuli may indicate danger in the past but does not indicate danger in the present moment.
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