Mindfulness Training in Dialectical Behavior Therapy Investigation on Brain Activity by NIRS

Abstract

In the last years, mindfulness as a therapeutic tool has proven clinical effectiveness on psychiatric patients and in the field of psychotherapy. First research on mindfulness revealed positive effects on chronic pain and stress reduction and mindfulness to be suitable and effective in treating psychiatric patients (Y. Tang & Leve, 2016). So far, it is still unknown if mindfulness skills are more effective than other therapeutic skills. Dialectical behavior therapy (DBT) integrates mindfulness skills (taken from Zen Buddhism) into cognitive behavioral therapy. DBT was developed in the 1980s by Marsha Linehan to treat suicidal patients with emotion regulation problems. Today, this treatment is known to be evidence based for treating borderline patients (Bohus & Schmahl, 2006). Linehan describes mindfulness as the basic ingredient of DBT. There is still no evidence on the effectiveness of mindfulness skills and the underlying neuronal correlates, and it is still unknown if mindfulness can be successfully learned in an eight-week inpatient setting. This thesis will test this question. We conducted three studies to get first insights in this topic: In study 1 we tested meditation experts against a group of subjects without meditation experience. We used a paradigm using mindful listening to a sound of a swinging meditation bell. This paradigm used near-infrared spectroscopy (NIRS) as an functional imaging technique and was taken from a pilot study of Erb et al. (2011). The second study measured executive function and underlying neuronal correlates in both groups of study 1 with a verbal fluency task (VFT) and an emotional Stroop test (EST). Since borderline patients suffer from severe impulse and emotion control issues, we wanted to know if mindfulness would have positive effects on impulsivity and emotion regulation. The results of study 1 and study 2 should give us first insights for study 3. There, we tested borderline patients with the mindfulness paradigm. We tested psychopathology and underlying neuronal correlates of two groups of borderline patients. We conducted the following 3 studies for this thesis.

Study 1) In this study we measured the hemodynamic responses of meditation experts (14 participants) and a control group (16 participants) in a resting and a mindfulness condition. In both conditions, the sound of a meditation bowl was used to find group differences in the auditory system and adjacent cortical areas. Different lateralization patterns of the brain were found in expert meditators while being in a resting state (amplified left hemisphere) or being in mindfulness state (amplified right hemisphere). Compared to the control group, meditation experts had a more widespread pattern of activation in the auditory cortex, while resting. In the mindfulness condition, the control group showed a decrease of activation in higher auditory areas (BA 1, 6 and 40), whereas the meditation experts had a significant increase in those areas. In addition, meditation experts had highly activated brain areas (BA 39, 40, 44 and 45) beyond the meditative task itself, indicating possible long-term changes in the brain and their positive effects on empathy, meta-cognitive skills, and health.

Study 2) This study investigated if a group of healthy meditation experts had better performances on two executive tasks (emotional word Stroop task and VFT) than healthy controls (same group of participants as in study 1). Besides performance, we measured brain activity (in the prefrontal cortex) of the two groups and tested the influence of a preceding short mindfulness task. We measured brain function in the prefrontal cortex of two different executive tasks by using near infrared spectroscopy (functional NIRS). Using the affective Stroop task, we tested if meditation experts had better executive function (stronger activation of the prefrontal cortex (PFC)) in terms of emotional control (stability). Using the VFT, we tested differences in word fluency and flexibility among both groups and corresponding differences in brain activation. In addition, we investigated the influence of a 9-minute block of mindfulness practice (9 minutes of mindful listening to the sound of a meditation bowl) conducted before the executive tasks. Accuracy in Stroop performance was significantly enhanced in the meditation group. In the interference condition of the Stroop Task (emotional words), meditation experts did not perform better. In addition, we did not find meditation experts to perform better on the VFT. A preceding short mindfulness task had no effects on performance of the VFT or Stroop task, but enhanced specific brain activation in the PFC as measured by fNIRS.

Study 3) Neuronal correlates of Borderline Personality Disorder are characterized by an imbalance of frontal-limbic brain areas (hypo- and hyper-activation). Little is known so far about the role of temporo-parietal parts of the brain in the dysfunction of borderline patients. We investigated the effectiveness of mindfulness as a therapeutic tool in the treatment of 29 borderline patients by comparing the therapeutic effects of 8 weeks of DBT therapy with 8 weeks of cognitive behavioral therapy without mindfulness (15 patients). Both treatments had significant positive effects on specific symptom reduction (borderline symptoms, dissociation, and behavior avoidance motivation), and an increase in mindfulness scores. We also found DBT to be significantly more effective in global symptom reduction and a trend for an increase in reward seeking behavior. On the neuronal level, the impact of 8 weeks of mindfulness on the temporo-parietal junction (TPJ) and superior temporal gyrus (increase in activity) of both hemispheres was correlated with general symptom reduction (SCL-90-R) and increased mindfulness scores (KIMS-D). In conclusion, we could show that mindfulness skills can reduce global psychopathology and make an impact on neuronal activity changes in borderline patients.