Prolonged exposure typically is applied at an individual level, one on one with a psychotherapist who has the appropriate training. You begin with a series of sessions on psycho-education. You might include progressive muscle relaxation. You might include interoceptive exposure depending on the patient-specific symptom set. Thereafter, you would go about a series of what we call exposures, usually imaginal exposures, so the patient begins re-engaging with the trauma.
One of the key things that we know supports ongoing maintenance in post-traumatic disorder symptoms is avoidance. It makes perfect, reasonable sense that if you had a traumatic experience, you are not interested in thinking about that traumatic experience again and again. Unfortunately, that avoidance behaviour can often also cause the symptoms that we see associated with post-traumatic stress disorder.
So it becomes a facilitating mechanism. You engage with that trauma in an appropriate way, and in an appropriate environment, by having the patient retell the trauma, having the patient imagine the trauma, and work with the psychotherapist in order to take some of the sting or the edge off, if you will. It doesn't remove the memory, but instead of having it be debilitating to consider what had happened, we can make it distressing. Eventually, hopefully, we can make it an unfortunate memory as opposed to something that the patient is having to re-engage with daily.
That is prolonged exposure in a nutshell.