Corrigendum: Mechanical affective touch therapy for anxiety disorders: Feasibility, clinical outcomes, and electroencephalography biomarkers from an open-label trial.

[This corrects the article DOI: 10.3389/fpsyt.2022.877574.].

Mechanical Affective Touch Therapy for Anxiety Disorders: Feasibility, Clinical Outcomes, and Electroencephalography Biomarkers From an Open-Label Trial.

Background: Most external peripheral nerve stimulation devices designed to alter mood states use electrical energy, but mechanical stimulation for activation of somatosensory pathways may be harnessed for potential therapeutic neuromodulation. A novel investigational device for Mechanical Affective Touch Therapy (MATT) was created to stimulate C-tactile fibers through gentle vibrations delivered by piezoelectric actuators on the bilateral mastoid processes. Methods: 22 adults with anxiety disorders and at least moderate anxiety symptom severity enrolled in an open-label pilot trial that involved MATT self-administration using a simple headset at home at least twice per day for 4 weeks. Resting EEG data were acquired before and after a baseline MATT session and again before the final MATT session. Self-report measures of mood and anxiety were collected at baseline, week 2, and week 4, while interoception was assessed pre- and post-treatment. Results: Anxiety and depressive symptoms improved significantly from baseline to endpoint, and mindfulness was enhanced. EEG metrics confirmed an association between acute MATT stimulation and oscillatory power in alpha and theta bands; symptom changes correlated with changes in some metrics. Conclusion: Open-label data suggest MATT is a promising non-invasive therapeutic approach to anxiety disorders that warrants further development.

Mechanical Affective Touch Therapy for Anxiety Disorders: Effects on Resting State Functional Connectivity.

OBJECTIVES: Mechanical Affective Touch Therapy (MATT) is a safe, novel form of noninvasive peripheral nerve stimulation. Although mechanical stimulation activates nerves, we know little about its impact on psychiatric symptoms and their underlying cortical mechanisms. We examined the effects of open-label MATT on resting state functional connectivity (RSFC) and its relationship with anxiety and affective symptomatology (clinical results in separate report). MATERIALS AND METHODS: A total of 22 adults with an Axis I anxiety disorder were recruited from the community. After two initial sessions assisted by research staff, participants self-administered 20-minute sessions of MATT at home at least twice daily for four weeks. Self-report measures of mood and anxiety severity were collected at baseline, two weeks, and four weeks. Resting state functional magnetic resonance imaging was collected before the initial MATT session (n = 20), immediately after the first session (n = 18), and following four weeks of MATT (n = 14). Seed-based whole-brain functional connectivity analyses identified brain connectivity patterns correlated with responsiveness to MATT. Seeds were based on Neurosynth meta-analytic maps for "anxiety" and "pain" given MATT's hypothesized role in anxiety symptom amelioration and potential mechanism of action through C-tactile afferents, which play an important role in detecting pain and its affective components. Connectivity results were corrected for multiple comparisons (voxel p < 0.005, cluster p-FDR < 0.05). RESULTS: Baseline RSFC is predictive of symptom improvement with chronic MATT. Acute increases in insula connectivity were observed between mid-cingulate cortex and postcentral motor regions following the first MATT session. Chronic MATT was associated with increased connectivity between pain and anxiety regions of interest (ROIs) and posterior default mode network (DMN) regions involved in memory and self-reflection; the connectivity changes correlated with decreases in stress and depression symptoms. CONCLUSIONS: MATT is associated with alterations in RSFC in the DMN of anxiety disorder patients both acutely and after long-term administration, and baseline RSFC is predictive of post-treatment symptom improvement.

Audio-Guided Mindfulness Meditation During Transcranial Magnetic Stimulation Sessions for the Treatment of Major Depressive Disorder: A Pilot Feasibility Study.

Background: Mindfulness-Based Cognitive Therapy (MBCT) has been shown to enhance the long-term treatment outcomes for major depressive disorder (MDD), and engagement of specific brain activities during brain stimulation may produce synergistic effects. Audio-guided meditation exercises are a component of MBCT that might be combined with standard transcranial magnetic stimulation (TMS) therapy sessions. We developed and pilot-tested a modified MBCT protocol for patients undergoing a standard course of TMS for MDD. Methods: Four MBCT audiotracks with differing durations and types of mental focus were selected. Patients listened to the audiotapes through headphones during daily TMS sessions for 5 consecutive weeks. The primary goal was to evaluate the feasibility and acceptability of the meditation intervention with TMS. Changes in self-rated measures of symptom severity, stress, life satisfaction, and mindfulness were also assessed. Results: Seventeen depressed subjects completed the study and 12 terminated early. Reasons for discontinuation included an inability to meditate in the treatment setting and induction of negative mood states. TMS percussive sensations and clicking sounds hindered the ability of patients to fully concentrate on or hear the voice of the audiotape narrator. Some became overwhelmed or felt increased pressure, anxiety, or aggravation trying to do meditation exercises while receiving TMS. Conclusion: There is a growing interest in combining TMS with other concurrent psychotherapeutic interventions to optimize treatment outcomes. The results highlight numerous feasibility issues with MBCT via guided audiotapes during TMS treatment. Future work should draw on these shortcomings to evaluate the appropriateness of MBCT for depressed patients undergoing neuromodulation.

Effects of transcranial magnetic stimulation on anhedonia in treatment resistant major depressive disorder.

BACKGROUND: Anhedonia is one of the defining features of depression but it remains difficult to target and treat. Transcranial magnetic stimulation (TMS) is a proven treatment for depression, but its effects on anhedonia and whether anhedonia can be used as a predictive biomarker of response is not well known. METHODS: Snaith-Hamilton Pleasure Scale was administered to patients with depression before and after a standard course of TMS in a naturalistic outpatient setting. RESULTS: 144 patients were analyzed. There was an overall significant improvement in anhedonia from pre- to post-treatment (7.69 ± 3.88 vs. 2.96 ± 3.45; p < .001). Significant correlations between improvements in anhedonia and other depressive symptoms were present (r = 0.55, p < .001). Logistic regression revealed that baseline anhedonia severity was not a significant predictor of clinical outcome. CONCLUSION: This is the first large, naturalistic study examining the effects of standard, non-research TMS on anhedonia. Among depressed patients, TMS resulted in significant improvements in anhedonia. Patients with severe baseline anhedonia had an equal chance of achieving clinical response/remission. Patients with anhedonia should not be excluded from treatment if they are safe for outpatient care and otherwise appropriate candidates for treatment.