Magneto-encephalographic (MEG) brain recordings during traumatic memory recall in women with post-traumatic stress disorder: A pilot study

The experiment studied the effects of a short duration exposure to traumatic memories using magneto-encephalography (MEG). Nine right-handed DSM-4 PTSD patients were recruited from a unit for anxiety disorders and an organisation supporting victims of violence. In order to have a homogeneous sample, we included only women who suffered from civilian PTSD. Exclusion criteria were co-morbid major medical illness, metallic dental prostheses that would interfere in the magnetic measurement, and current drug treatment. All participants were free from neurological disease and had normal hearing. They signed a written informed consent form. An ethics committee accepted the study. A tape-recorded voice administered a script-driven imagery. The patients had to imagine, successively, a neutral image, a traumatic memory and rest, while MEG measured brain activities across delta, theta, alpha and beta bands. Each condition lasted three minutes. Heart rate (HR), anxiety and the vividness of mental images were recorded at the end of each phase. MEG power analysis was carried out with Statistical Parametric Mapping (SPM) 8. The signals were averaged for each of the three conditions of threeminutes duration. The dependent variable was a subtracted value: (trauma - rest) - (neutral - rest). The significance threshold was set at P