Neural correlates of trauma-focused psychotherapy in PTSD: A longitudinal fMRI investigation

Post-traumatic stress disorder (PTSD) is a debilitating condition in which
patients suffer from intrusions, avoidance, and hyperarousal following a
traumatic event. Trauma-focused psychotherapies (TFT), including exposure and
re-processing of the traumatic memories, are most effective in reducing PTSD
symptomatology. Approximately one third of PTSD patients do not depict
noteworthy improvements following treatment, and no reliable predictors for
treatment outcome have been identified yet. A promising path towards finding
objective treatment predictors is to understand brain-based characteristics and
the neural underpinnings of PTSD symptomatology. Neurobiological models suggest
that PTSD symptoms correspond with dysfunctional fronto-limbic neural circuitry
and that psychotherapy strengthens top-down modulation of hyperactive limbic
regions. Meanwhile, it has been hypothesized that PTSD patients with elevated
dissociation levels do not respond equally well to treatment as dissociation is
expected to interfere with habituation during exposure and negatively affects
lower brain regions regulating physical reactions. Only few neuroimaging
pre-post treatment studies in PTSD have provided empirical evidence for the
proposed models. There is a strong necessity for well-powered neuroimaging
research to identify treatment-related changes in brain function and neural
predictors of who will and will not profit from trauma-focused therapy.

The current study*s primary aim is to test how trauma-focused therapy affects
PTSD symptom-specific neural activity, and investigate neural markers that may
predict treatment response to trauma-focused exposure. Furthermore, it is
expected that assessment of psychophysiological reactivity and functional
connectivity between regions of interest can elucidate other potential markers
of psychotherapeutic gains in PTSD.

The current study employs an observational pre-post therapy design in which
symptom-related brain activation of 60 PTSD patients enrolled in trauma-focused
therapy will be assessed before and after the trauma-processing phase. During
functional neuroimaging, participants will undergo two experimental tasks. The
first task is script-driven imagery, in which participants attentively listen
to an audiotaped narrative of a personal a) traumatic and b) neutral event in a
blocked design. The second task is an emotion reactivity task to assess neural
correlates of conscious and non-conscious processing of fearful (vs. neutral)
faces.

Participation consists of 4 sessions (total duration: 7 hours); Participants
undergo a neuroimaging session (duration: 90 min) and a clinical assessment
session (duration: 60-120 minutes) once before and after therapy. The first
clinical assessment session comprises a clinical interview (45-60 minutes),
script collection (30 minutes), and filling out a questionnaire booklet (60
minutes). In the neuroimaging sessions, participants answer several
questionnaires (30 minutes), and then undergo fMRI scanning (45 minutes)
including two tasks (script-driven imagery and emotional reactivity). During
scanning, the participants* psychophysiological data (heart rate, skin
conductance reactivity, and respiration) will be recorded. The second clinical
assessment session entails an interview to assess PTSD severity post-treatment
(45-60 minutes). While acknowledging the participation burden and potential
distress related to the study procedures, all techniques have been extensively
tested in traumatized patient groups and trauma-focused research participation
has presented minimal risk to its subjects. Concerning the fMRI scanner,
participants will be exposed to a field strength of 3 Tesla and scanner noise.
Thus far, there is no evidence to suggest that exposing humans to a magnetic
field of this strength has a negative influence on health. With regard to the
noise, earplugs will be provided. To minimize the risk of claustrophobic
sensations in the scanner, patients will be screened for a history of
claustrophobia and will be offered to lay in a mock scanner to estimate their
comfort level inside a MR scanner. No disadvantages of the heart rate measures
and skin conductance measures are known or expected. The study is not intended
to benefit the participants directly, but they will receive a compensation of ¤
70,- for their participation.