ORIGINAL PAPER Measuring Meditation Progress with a Consumer-Grade EEG Device: Caution from a Randomized Controlled Trial Rebecca L. Acabchuk 1 & Mareyna A. Simon 1 & Spencer Low 1 & Julie M. Brisson 1 & Blair T. Johnson 1 # Springer Science+Business Media, LLC, part of Springer Nature 2020 Abstract Objectives Consumer-grade electroencephalogram (EEG) devices designed to assist people with meditation are gaining popu- larity. This study investigates EEG-based outcome measures provided by the Muse device and their relation to mindfulness scores and mental health in a meditation intervention. Methods Fifty-three novice meditators (university students taking part in the registered clinical trial NCT03402009) were asked to meditate 10 min per day for 1 month, randomly assigned to use (1) meditation app (“app group”) or (2) meditation app, plus Muse neurofeedback device (“Muse group”). Pre- and post-intervention measures include Muse EEG scores assessed in a 5-min meditation and self-report scales of mindfulness and distress. A satisfaction survey and brief interview were conducted post- intervention. Results Baseline levels of mindfulness on MINDSENS were not correlated with “calm” scores on Muse. Following the 1-month meditation intervention, neither meditation group demonstrated improvements in EEG outcome measures according to the Muse app; in fact, the app group performed significantly worse at follow-up compared to baseline according to Muse’s user scores. Conversely, both groups showed significantly reduced distress and increased mindfulness scores following the intervention. Seventy-six percent of participants meditated at least three to four times per week, and both groups reported high levels of satisfaction with their meditation device (84% app group; 74% Muse group). Conclusions Users, researchers, and clinicians should use caution in interpreting EEG outcomes on consumer-grade neurofeedback devices. Results suggest EEG outcome scores are not a proxy for mindfulness score, meditation practice, mental health status, or improvement over time in young adult novice meditators. Trial Registration https://clinicaltrials.gov/ct2/show/NCT03402009 Keywords Mindfulness . RCT . EEG . Muse . Neurofeedback . Meditation With the growing interest in mindfulness meditation and using technology for self-improvement (Swan 2013; Yetison 2018), consumer-grade electroencephalogram (EEG) devices de- signed to assist users in learning how to meditate are becom- ing more widely used in the general public, as well as in clinical and research settings. Mindfulness meditation, which focuses on training the mind to pay attention in a particular way to become aware of present moment experience with an attitude of curiosity and acceptance (Bishop et al. 2004), shows promise in both healthy and clinical populations to improve a variety of markers for health, aging, and well-being, including mood-related (e.g., stress, anxiety, depression) (Hofmann et al. 2010; Schreiner and Malcolm 2008), cogni- tive (e.g., attention, focus) (Bhayee et al. 2016; Bueno et al. 2015), and physical (e.g., pain, fatigue, inflammation) (Kabat- Zinn et al. 1985; Rosenzweigh et al. 2010) symptoms. Growing in popularity are consumer-grade EEG devices that claim to assist people in learning how to meditate by provid- ing users with feedback on their mental state based on brain wave frequency. Researchers have proposed that increased levels of dispo- sitional mindfulness may be a key mechanism of action mod- ulating the health benefits found in mindfulness-based inter- ventions (Garland et al. 2017; Tomlinson et al. 2018). * Rebecca L. Acabchuk Rebecca.acabchuk@uconn.edu 1 Department of Psychological Sciences, Institute for Collaboration on Health, Intervention, and Policy, University of Connecticut, 2006 Hillside Road, Unit 1248, Storrs, CT 06269-1248, USA Mindfulness https://doi.org/10.1007/s12671-020-01497-1