This paper presents a narrative review of research literature to “map the landscape” of the mechanisms of the effect of sound vibration on humans including the physiological, neurological, and biochemical. It begins by narrowing music to sound and sound to vibration. The focus is on low frequency sound (up to 250 Hz) including infrasound (1–16 Hz). Types of application are described and include whole body vibration, vibroacoustics, and focal applications of vibration. Literature on mechanisms of response to vibration is categorized into hemodynamic, neurological, and musculoskeletal. Basic mechanisms of hemodynamic effects including stimulation of endothelial cells and vibropercussion; of neurological effects including protein kinases activation, nerve stimulation with a specific look at vibratory analgesia, and oscillatory coherence; of musculoskeletal effects including muscle stretch reflex, bone cell progenitor fate, vibration effects on bone ossification and resorption, and anabolic effects on spine and intervertebral discs. In every category research on clinical applications are described. The conclusion points to the complexity of the field of vibrational medicine and calls for specific comparative research on type of vibration delivery, amount of body or surface being stimulated, effect of specific frequencies and intensities to specific mechanisms, and to greater interdisciplinary cooperation and focus.

Chronic back pain is complex and there is no guarantee that treating its potential causes will cause the pain to go away. Therefore, rather than attempting to “cure” chronic pain, many clinicians, caregivers and researchers aim to help educate patients about their pain and try to help them live a better quality of life despite their condition. A systematic review has demonstrated that patient education has a large effect on pain and pain related disability when done in conjunction with treatments. Therefore, understanding and updating our current state of knowledge of the pathophysiology of back pain is important in educating patients as well as guiding the development of novel therapeutics. Growing evidence suggests that back pain causes morphological changes in the central nervous system and that these changes have significant overlap with those seen in common neurodegenerative disorders. These similarities in mechanisms may explain the associations between chronic low back pain and cognitive decline and brain fog. The neurodegenerative underpinnings of chronic low back pain demonstrate a new layer of understanding for this condition, which may help inspire new strategies in pain education and management, as well as potentially improve current treatment.

Recent studies have suggested that vibration therapy may have a positive influence in treating motor symptoms of Parkinson’s disease (PD). However, quantitative evidence of the benefits of vibration utilized inconsistent methods of vibration delivery, and to date there have been no studies showing a long-term benefit of 40 Hz vibration in the PD population. The objective of this study was to demonstrate the efficacy of vibration administered via a physioacoustic therapy method (PAT) on motor symptoms of PD over a longer term, completed as a randomized placebo-controlled trial. Overall motor symptom severity measured by the Unified Parkinson’s Disease Rating Scale III showed significant improvements in the treatment group over 12 weeks. Specifically, all aspects of PD, including tremor, rigidity, bradykinesia, and posture and gait measures improved. To our knowledge, this is the first study to quantitatively assess 40-Hz vibration applied using the PAT method for potential long-term therapeutic effects on motor symptoms of PD.

Major depressive disorder (MDD) is a persistent psychiatric condition and one of the leading causes of global disease burden. In a previous study, we investigated the effects of a five-week intervention consisting of rhythmic gamma frequency (30-70 Hz) vibroacoustic stimulation in 20 patients formally diagnosed with MDD. In that study, the findings suggested a significant clinical improvement in depression symptoms as measured using the Montgomery-Asberg Depression Rating Scale (MADRS), with 37% of participants meeting the criteria for clinical response. The goal of the present research was to examine possible changes from baseline to posttreatment in resting-state electroencephalography (EEG) recordings using the same treatment protocol and to characterize basic changes in EEG related to treatment response. The study sample consisted of 19 individuals aged 18-70 years with a clinical diagnosis of MDD. The participants were assessed before and after a five-week treatment period, which consisted of listening to an instrumental musical track on a vibroacoustic device, delivering auditory and vibrotactile stimulus in the gamma-band range (30-70 Hz, with particular emphasis on 40 Hz). The primary outcome measure was the change in Montgomery-Asberg Depression Rating Scale (MADRS) from baseline to posttreatment and resting-state EEG. Analysis comparing MADRS score at baseline and post-intervention indicated a significant change in the severity of depression symptoms after five weeks (t = 3.9923, df = 18, p = 0.0009). The clinical response rate was 36.85%. Resting-state EEG power analysis revealed a significant increase in occipital alpha power (t = -2.149, df = 18, p = 0.04548), as well as an increase in the prefrontal gamma power of the responders (t = 2.8079, df = 13.431, p = 0.01442). The results indicate that improvements in MADRS scores after rhythmic sensory stimulation (RSS) were accompanied by an increase in alpha power in the occipital region and an increase in gamma in the prefrontal region, thus suggesting treatment effects on cortical activity in depression. The results of this pilot study will help inform subsequent controlled studies evaluating whether treatment response to vibroacoustic stimulation constitutes a real and replicable reduction of depressive symptoms and to characterize the underlying mechanisms.

Ehlers–Danlos syndrome (EDS) is a connective tissue disorder characterized by joint hypermobility and skin extensibility and is often accompanied by chronic pain. Rhythmic sensory stimulation (RSS) can be defined as the stimulation of the senses in a periodic manner within a range of low frequencies. Music plus sound delivered through a vibroacoustic device is a form of RSS and has demonstrated utility in managing pain. In this current study, we conducted an open-label pilot study of 15 patients with hypermobile EDS using RSS as the intervention. Posttreatment improvements were seen in 11 of the 15 patients (73%), whereas 3 of the 15 patients (20%) experienced worse outcomes. Of the 14 patients that completed the experiment, 6 participants (43%) were classified as “responders” to the device while 8 participants (57%) were classified as “nonresponders.” Responders demonstrated significant improvements in pain interference (51.5 ± 16 preintervention vs. 43.5 ± 16.4 postintervention BPI score) and depression symptoms (34.0 ± 15.9 preintervention vs. 26.8 ± 12.1 postintervention CESD score). Poststudy interviews confirm the improvements of pain interference, mood, and bowel symptoms. Furthermore, analysis of medical conditions within the responder group indicates that the presence of depression, anxiety, irritable bowel syndrome, and fibromyalgia may indicate a greater likelihood for patients to benefit with vibroacoustic applications. These results indicate a possible potential for RSS, delivered using a vibroacoustic device, in managing pain-related symptoms. Further research is necessary to elucidate the exact mechanism behind the physiological benefits of RSS.

Cognitive dysfunction occurs in around 40% of long COVID (LC) patients, and in many cases appears second only to fatigue in prevalence. Vibratory and auditory treatment (VAT) within the gamma range has demonstrated improvements in symptoms associated with cognition and fatigue. In this open-label pilot study, we tested the effects of VAT on measures of cognition and fatigue in LC. Twenty patients were randomly divided into a treatment and a control group. Symptoms were monitored remotely through mobile apps and in-person visits before and after the treatment period. The treatment group received a device generating 40 Hz of VAT to take home and use every day from Monday to Friday for 4 weeks (i.e., 20 sessions over 28 days), whereas the control group did not use any device but followed the same data collection procedures. This study found that after 4 weeks of VAT, participants with LC exhibited increased performance in selective attention and response inhibition, an increased amount of circulating brain-derived neurotrophic factor (BDNF), and a reduced resting heart rate. We propose that VAT may be a useful rehabilitative tool for LC as well as other targeted populations that seek improvements in cognition or general health but are compromised immunologically or physically.