Introduction
Perceived stress levels have increased from the COVID-19 pandemic (TMGH-Global COVID-19 Collaborative, 2021;). Prior to the COVID-19 pandemic, perceived stress levels in diverse (age, gender, education, etc.) adults, as determined by the perceived stress scale (PSS-10), were approximately 16-18 pts (Champion, Economides, & Chandler, 2018; Cohen & Janicki-Deverts 2012; Andreou et al., 2011). Since the pandemic, average PSS-10 scores have increased to approximately 20-29 pts (Napoli, 2022; Aly et al., 2021; Meaklim et al., 2021; TMGH-Global COVID-19 (Collaborative, 2021; Adamsom et al., 2020; Agyapong et al., 2020), and those with anxiety disorders have higher perceived stress scores compared to nonanxious individuals (Mozumder 2022; Meaklim et al., 2021; Agyapong et al., 2020; Cohen & Janicki-Deverts, 2012; Andreou et al., 2011).
Prolonged stress severity can result in anxiety and depressive disorders (Khan & Khan, 2017) and negatively influence health and mortality (Keller et al., 2012). Moreover, excess stress can lead to an anxiety disorder relapse (Francis, Moitra, Dyck, & Keller, 2012). There are emotional differences between those with and without anxiety or depressive disorders. Individuals with anxiety and depressive disorder demonstrate affective hyperactivity and describe feeling more threatened and less in control of their emotions when compared to nonanxious individuals (Llera & Newman, 2010). Moreover, individuals with anxiety or depressive disorders have a lower positive affect and higher negative affect compared to individuals without these disorders (Díaz-García et al., 2021; Díaz-García et al., 2020, Crawford & Henry, 2004.; Watson, Clark, & Tellegen, 1988).
Emotion-focused coping is a component of stress management intended to lower perceived stress and negative affect. Emotion-focused coping includes soothing behaviors or mechanisms that provide extrinsic and intrinsic processes involved in monitoring, evaluating, and modifying emotional reactions (Gross, 1998; Lazarus, 1993). Soothing activities may include listening to music, taking a shower, massage, and meditation. Listening to music was one of the most effective coping strategies during the COVID-19 pandemic (Krause, Dimmock, Rebar, & Jackson, 2021; Ribeiro, Lessa, Delmolin, & Santos, 2021; Vidas, Larwood, Nelson, & Dingle, 2021 ). In addition, non-noxious sensory activities (e.g., touch, massage) for relaxation appear to lower physiological stress markers (e.g., heart rate, blood pressure, and cortisol levels) and increase hormones (oxytocin, serotonin, and dopamine) associated with positive mood and mental well-being (Field, Hernandez-Reif, Diego, Schanberg, & Kuhn, 2005; Lindgren, Rundgren, Winsö, Lehtipalo, Wiklund, et al., 2010; Uvnäs-Moberg, Handlin, & Petersson, 2015).
Sensate® (BioSelf Technology, London, England) is a vibrotactile wellness device providing a non-noxious, somatosensory activity called Somacoustics (McDoniel & Chmelik, 2022). Somacoustics combines infrasonic resonance with aural soundscapes, which posits a soothing experience for emotion-focused coping. This proposed activity is like vibroacoustic therapy, which uses infrasonic sound (< 50 Hz) to produce vibrations while applied to the body (Skille, 1989). Skille (1989) suggests that vibroacoustic stimulation may improve stress-induced depression, anxiety, tension, and fatigue. Bartel and Mosabbir (2021) offered a theoretical basis using sound vibrations, including infrasound, for various health benefits but acknowledged the complexity of sound vibrations and suggested additional research is needed exploring delivery types (e.g., sound frequency, body location) on various health conditions. A 2013 qualitative study was conducted with 11 individuals completing six (30-60 minute) sessions of low-frequency (27-113 Hz) sound applied to the posterior side of the whole body while individuals were in a chair (Ahonen, Deek, and Kroeker, 2013). Individuals were instructed to close their eyes during each session. However, there was no indication of additional music added for listening. Subjective improvement in perceived stress and emotional enrichment (e.g., inner peace, self-awareness, and clarity) was noted, and individuals reported a positive experience from the sessions (Ahonen, Deek, and Kroeker, 2013). However, no formal stress or emotional questionnaires were used for assessment. A 2019 study implemented low-frequency (Hz level not disclosed) music impulse stimulation on the abdomen of 18 adults with depression while they listened to synchronized music (Sigurdardóttir et al., 2019). Individuals completed eight 20-minute sessions throughout 1-month. Results from the study suggest a significant improvement in the Hamilton Depression Rating scale and improvement in depressive symptoms with no adverse side effects (Sigurdardóttir et al., 2019). These findings do offer some possible support for low-frequency vibroacoustic stimulation for stress and depression, but additional research is needed, as recommended by Bartel and Mosabbir (2021).