EEG theta enhancement and heart rate variability biofeedback on interactional stress in a clinical population

The study sought to investigate the roles of two applied psychophysiology and biofeedback treatments, theta enhancement neuronal feedback (NFB) and heart rate variability (HRV) biofeedback on stress as measured by the interactional model of the Derogatis Stress Profile (DSP) at one-month follow-up. It was hypothesized that the biofeedback groups would achieve greater reduction in stress than the control group and that there would be different effects between the two treatment groups on stress dimensions and global indices. Theta enhancement NFB is associated with deep clinical relaxation. Therefore, it was hypothesized that the stress dimensions of Time Pressure, Driven Behavior, Relaxation Potential, and Anxiety would be lower post experiment for the NFB group than for the HRV group. Also, it was hypothesized that the global indices of the DSP would be lower for the NFB group. The goal of HRV biofeedback is to reduce health risk and enhance positive affect such as qualities associated with expansion of the heart such as love and appreciation. Parasympathetic respiration dominance exerts powerful control of heart rate variability (HRV). This makes it difficult to assess cognitive and emotional effects on HRV. Low (HRV) is a diagnostic biofeedback measure for illness and sudden cardiac death. Thirty participants from a population with diagnoses of stress-related illness were randomly assigned to three groups: a HRV biofeedback treatment group with a computer algorithm to reduce the effects of extreme respiration patterns (n = 10), a theta enhancement neuronal feedback (NFB) group (n = 10), and a control group (CG) (n = 10). Results indicated that the NFB group showed significantly more improvement than the HRV group on global measures of stress and on the dimensions of Time Pressure, Relaxation Potential, Health Environment, and Anxiety but, not on Driven Behavior. The HRV group showed a significantly greater reduction in the Hostility Dimension. Both experimental groups showed a measurable reduction in perceived stress. Qualitative differences were found to be in accord with the literature. As expected, EEG theta amplitude was significantly elevated in the NFB group. Heart rate was significantly reduced for the HRV group. Neuronal biofeedback was more effective than HRV biofeedback for stress reduction.