Vibroacoustic therapy research:
the science of low-frequency sound.

The therapeutic use of low-frequency sound vibration delivered directly to the human body has been studied for around thirty years (Skille, 1986). In the early 1980s Skille and his collaborators built the so-called “bath of sound”: a massage table with loudspeakers coupled directly to its surface. The person lying on it heard traditional repertoire rich in low frequencies — organ, double bass, bassoon — but also received, more faintly, the vibration transmitted straight into the body. The research group understood that this bodily reception was the real novelty.

What followed was the systematic separation of the fundamental, or “root” sound, which acts mainly at body level, from derived sound built on harmonics, which is perceived mainly through the ear. Using a frequency generator as the source, it becomes possible to send only precise, pure sinusoidal signals — free of harmonics — able to act directly on the part of the body being treated.

Studies have shown that soft zones resonate at the lowest frequencies, while higher frequencies engage thin musculature and bone (Griffin, 1983). The principle is simple: everything resonates, and the human body behaves no differently. Stimulated by distinct low-frequency impulses, it acts like a tuning fork, entering resonance in specific zones according to the frequency sent (Kriscak & Raffaelli, 2010).

Applying a low-frequency source directly to the body uses the penetration of acoustic waves to restore, by resonance, natural vibrations that for various reasons are no longer produced normally. Low-frequency vibration acts on non-auditory tissue through mechanisms involving both the physical properties of acoustic waves — in particular their coherence — and the biophysical properties of many tissues: piezoelectricity, semiconductivity, and the bipolar character of water and of many organic macromolecules, DNA included (Bistolfi, 2000).

Each frequency corresponds to a determined note, and by logarithmic law a sound value can be assigned to every emitted frequency (Pierce, 1983). A flow between 40 Hz and 50 Hz, for example, is suitable for reducing hypertonia of the extensor and flexor muscles in patients with cerebral palsy (Ruutel, 2002).

Research in vibroacoustic therapy is developing in particular in Canada, at Wilfrid Laurier University in Waterloo, and in Finland at the University of Jyväskylä, where a team coordinated by Professor Sulin Cheng of the Department of Health Sciences evaluated the effects of low-frequency signals on functional capacity, blood circulation and bone metabolism in frail old men and women (Cheng, Zheng, Sakari & Hietikko, 2009). The results highlighted high potential in the treated cases.

Low-frequency vibration has since been studied in senile dementia with sleep disturbance (van Os, Aziz, Schalkwijk, Schols & de Bie, 2012), where its use had a marked positive effect on treated patients, including against a parallel pharmacological comparison.

A study by the Department of Occupational Therapy of the Faculty of Health and Wellbeing at Hiroshima University (Koike et al., 2012) tested whether IVA could reduce depressive symptoms in fifteen elderly nursing-home residents. Assessed through the Mood Assessment Scale, tympanic temperature, pulse, arterial pressure and actigraphic measurement, a significant reduction in depressive symptoms and an improvement in the sleep cycle were observed.

On mobility and balance, Bautmans and colleagues (2005) documented improvements in muscle performance, balance and mobility in institutionalised elderly persons, while Bruyère and colleagues (2005) showed that low-frequency vibration improves balance disorders caused by muscular asthenia and vestibular deficit, increasing motor capacity and gait, with a consequent reduction in the risk of falls and fractures (Bistolfi, 2009).

One of the most consistently encouraging applications of IVA concerns autism. In a study carried out in Kolkata in 2008 (Dutta Roy, Kakali & Ghost), autistic behaviours were assessed before and after IVA sessions using the Vineland Social Maturity Scale, the Gilliam Autism Rating Scale and the Autism Behavior Anchor Rating Scale. All three scales showed a positive effect of IVA on autistic behaviours.

A 2011 doctoral thesis at the Department of Communication and Psychology, Faculty of Humanities, Aalborg University (Bergström-Isacsson) examined the effects of IVA combined with sound stimuli on the control of autonomic nervous system functions and on cortical emotional reactions in patients with Rett syndrome.

Benefits have also been reported in abdominal and colic pain (Aldridge & Brandt, 1991), and further work has focused on the neurophysiological improvement of motor responses evoked by vibratory stimulation (Bishop, 1974).

In multiple sclerosis, work conducted by Prisby and colleagues (2008) indicates that IVA can be considered optimal in comparison with certain pharmacological therapies.

In 2005 Turbanski conducted a study on 52 Parkinson's patients which demonstrated that a cycle of IVA sessions led to an improvement in their postural stability. In Italy, studies on this theme have been carried out by the music therapist Riccardo Della Ragione.

Research on subjects recovering from stroke (Van Nes, Latour, Schils et al., 2006) underlines how IVA optimises balance control in the post-acute phase, with long-term effects on activities of daily living.

Many studies on the therapeutic effect of low-frequency sound vibration have concentrated on pain control (Boyd-Brewer & McCaffrey, 2004; Kriscak & Raffaelli, 2010; Chesky & Michel, 1991).

Rittweger and colleagues (2002) started from the premise that the pathophysiology of chronic lower back pain involves not only the nervous system but also musculature and connective tissue. Their randomised controlled trial showed that low-frequency vibration, like lumbar extension exercise, is able to relieve chronic lower back pain and consequently improve quality of life (Bistolfi, 2009).

Further work with very encouraging results has been carried out on the reduction of pain caused by rheumatoid arthritis (Chesky, 1992), on the treatment of fibromyalgia through sound resonance technology (Cogan, Camus, Saucier, Arsenault & Demers, 2006), on increased resistance to competitive training loads (Delecluse, Roelants & Verschueren, 2003), on the decrease of arterial stiffness (Otsuki et al., 2008), and on the release of muscular rigidity and spasticity (Semler et al., 2007; Hagbarth & Eklund, 1968).

An Italian study by Melchiorri and colleagues (2007) found IVA very useful for paraplegic wheelchair users, improving arm strength and consequently both propulsion of the chair and postural transfers — chair to bed, chair to toilet, chair to car.

Cellulite — known in medicine as oedematous-fibrosclerotic panniculopathy (PEFS) — affects 80–90% of women. It is an effect of the degeneration of blood and lymphatic microcirculation in the subcutaneous adipose tissue, the hypodermis, which alters normal metabolic function. Where microcirculation is significantly impaired, lipolysis is altered, fluid is produced in the extracellular spaces and waste substances accumulate there and are difficult to clear.

When local alterations persist, a progressive degenerative mechanism is triggered: inflammation, oedema and thickening of the connective tissue up to fibrosis, with the typical formation of micronodules — enlarged fat cells compressed inside thickened connective tissue. The skin takes on the characteristic orange-peel appearance and can be painful to the touch.

Sound resonance is the physical principle behind the effect of the GA.IA sound-wave bed on these tissues. Resonance is the transmission of a vibration from one body to another: strike a tuning fork and a second tuning fork tuned to the same frequency will begin to vibrate — sympathetic resonance, well known in music.

In the same way, when the GA.IA bed emits low-frequency vibration it activates, by sympathy, the corresponding vibrations specific to parts of the body. The bed emits in the range between 20 and 80 Hz; between 30 and 36 Hz the parts affected by cellulite — thighs, hips and waist in particular — resonate.

Sound vibration generates a regular, continuous movement of tissues, which are largely composed of water and other mobile substances. The same movement can be observed by placing a basin of water on the GA.IA bed: within seconds the sound produces vortices rising from below to the surface.

By resonance the bed produces a deep massage, from the inside outwards, continuous and constant, capable of reactivating the whole microcirculation — both blood and lymphatic — inducing a strong draining and detoxifying effect with a mild lipolytic effect linked to the induced passive movement. Oedemas disappear, cellulite nodes dissolve, connective tissue softens, throughout the depth and across the whole surface reached by the vibration.

Unlike shockwave, roller or cavitation devices, the vibration is non-invasive: it exerts no unnatural pressure or impact against capillaries and vessels, leaves no redness or bruising, requires no preparation of the client and no operator present during the session. The only tangible sign of the work in progress is a light tingling under the skin, which can persist for some time after the session.

The research was conducted at the C.A.R.M.A. centre (Center Advanced Research and Mental Aid), specialised in the treatment of neuroses using virtual reality and equipment able to act beyond the purely human factor. Technology in the service of the person: “no drug no blood” was the motto, and every intervention followed it. The vibroacoustic bed, built to Diego Kriscak's design, had until then been used in that context — difficulty sleeping, anxiety attacks, stress.

The research team comprised Alberto Raffaelli (brain analyst), Adriana Barbina (scientific coordinator), Tullio Fragiacomo (analyst) and Diego Kriscak (vibrotherapist). The work started from the premise that low frequencies tend to bring into resonance the parts of the body subjected to a sinusoidal sound stimulus — a signal free of derived sounds or harmonics, so that it is the body itself that resonates, behaving in practice like the sound box of an instrument.

Three questions framed the study. Which frequency or band should be used to obtain results? How many sessions, and how many days apart, would produce positive results — and how long would those results last? And could sound be used at a perceptual level to accompany the primary effect with a relaxation effect, including through the delivery of brain waves?

The session protocol was fixed: take measurements of waist, hips, thighs, knees and arms; run the vibroacoustic session for thirty minutes; switch off the bed; take all measurements again; and collect feedback on the session. Contraindications were identified and screened before admission.

The resulting dataset records every subject session by session — first through eighth — with measurements at each stage. It is presented analytically in the C.A.R.M.A. 2013 report and evaluated in the DIREDI reports of 2014–2015. Text rights reserved, DIREDI SRL, Azzano Decimo (PN), Italy.