**5. Applied psychophysiological therapy for PTSD and attention bias: HRV biofeedback**

trials). An attention bias score is calculated as the difference between the mean reaction times

54 A Multidimensional Approach to Post-Traumatic Stress Disorder - from Theory to Practice

Attentional bias toward threat in PTSD could reflect either difficulty disengaging from threat‐related stimuli or facilitated engagement of such stimuli, although there is some evi‐ dence that attentional bias toward threat in PTSD reflects difficulty disengaging as opposed to facilitated engagement [77]. Early dot probe studies in PTSD in adults and children re‐ ported mixed findings. Some studies found bias toward trauma or threat‐elated stimuli in PTSD [78–82], while others reported an association between PTSD and a bias away from trauma or threat [83, 84]. Still others have failed to find significant attentional bias differen‐ ces between PTSD and control groups, consisting of healthy individuals and a group of re‐ cent trauma survivors that included individuals both with and without acute stress disorder [85, 86]. Difficulty disengaging from threatening stimuli has been associated with the 5‐ HTTLPR serotonin transporter gene polymorphism [87], although the significance of this

Iacoviello [88] derived a measure of attention bias by grouping, or "binning," consecutive 20‐ trial sequences on the dot‐probe task and calculating a bias score for each bin. The standard deviation of the bias scores across bins was then divided by the participant's mean reaction time to generate the measure of attention bias for each subject throughout the session. Results of this study revealed greater attention bias in participants with PTSD than in trauma‐exposed participants without PTSD and nonexposed healthy participants. Attention bias was also

Different selective attentional orienting mechanisms underlying anxiety‐related attentional bias have been identified, such as engagement and disengagement of attention [89]. These mechanisms are thought to contribute to the onset and maintenance of general anxiety dis‐ orders and have relevance for the study of attention bias in PTSD. General anxiety seems to be associated with a preferential bias for negativity. The measure of attention bias has re‐ cently been refined by employing a moving average technique, rather than the previously employed binning method, to generate a more stable index that is influenced less by the number of trials in any particular study [90]. However, attention bias is still something of a novel measure, and we know of no reports of test‐retest reliability. Overall, attention bias may be best conceptualized as reflecting natural plasticity built into the threat‐monitoring system that is influenced by different contexts and situations, rather than indexing a stable

Attentional training (sometimes called attention bias modification, ABM) is aimed at reduc‐ ing symptoms and behaviors associated with anxiety by systematically reducing negative attentional biases and training selective attention to orient away, or to disengage, from threat [91]. Attention control training, but not attention bias modification, was found to sig‐ nificantly reduce attention bias and reduce PTSD symptoms [92]. Thus, further study of treatment efficacy for attention bias, and its underlying neurocognitive mechanisms, seems

of these two types of trials.

finding has not been explained.

trait.

warranted.

positively correlated with PTSD symptom severity.

The scientific and clinical data supporting the facts of diminished vagal and increased sympathetic activity in PTSD increased notably in the past decade and continue to mount [13]. In developing a treatment intervention, it is important to understand the signature patterns of normal and deranged stimulus processing and appraisal, and response output type, whether immobility, defense, or affiliative. Effective interventions aim to activate, deactivate, or modify one or more components of the abnormal cardiac adjustment pattern. Because the process of treatment intervention pertains to humans, we may speak of an intervention that shifts the response pattern of cardiac adjustment as being a "mind‐body intervention."

In our clinical research, we use HRVB as a psychophysiological intervention to study the effects of psychological trauma and its potential amelioration. HRVB is a very well‐tolerated, easy‐ to‐use, and effective mind‐body technique that appears to have achieved acceptance as an integrative health procedure for routine healthcare. HRVB training teaches the practitioner to self‐regulate his or her own HRV by monitoring visual feedback indicating whether or not HRV coherence is attained, and then associating that feedback with self‐regulation of emo‐ tional state. With practice, the individual learns how to voluntarily and quickly produce HRV coherence using RFB, focused attention, and conscious voluntary positive emotional state. HRVB is an interactive procedure that uses hardware/software systems to monitor and display the individual's HRV patterns in real time. Visual feedback of HRV (either quantitative display or animated challenge games) is provided as participants practice techniques of attention focusing (such as mindfulness), RFB, and induction of a positive emotional state. Acquisition of the skill of self‐regulation of HRV coherence takes anywhere from 1 to 6 weekly sessions of about 45 min each. Summaries of the evidence for the efficacy of HRVB in reducing mental and physical symptom burden are available [93–95].
