The effects of vibroacoustic therapy on clinical and non-clinical populations

http://www.wfmt.info/Musictherapyworld/modules/archive/stuff/papers/Wigram.pdf

Thesis submitted for the degree of Doctora of Philosophy, St. Georges Hospital Medical School London University

Anthony Lewis Wigram (author)

Abstract:

Vibroacoustic and vibrotactile devices that transmit sound as vibration to the body

have developed over the last 15 years, and have been reported anecdotally to

produce relaxation and reductions in muscle tone, blood pressure and heart rate.

Vibroacoustic (VA) therapy is used in clinical treatment and involves a stimulus that

is a combination of sedative music and pulsed, sinusoidal low frequency tones

between 20Hz and 70Hz, played through a bed or chair containing large speakers.

There is limited evidence to support the efficacy of VA therapy in the clinical

situations in which it is used. The studies in this thesis investigated the clinical effect

of VA therapy, and the effect of elements of the stimulus on non-clinical subjects.

A study on 10 multiply handicapped adults with high muscle tone and spasm

compared the effect of eight trials of VA therapy with a similar number of trials of

relaxing music. A significantly greater range of movement was recorded after VA

therapy than relaxing music. No significant difference was found in changes in

blood pressure or heart rate.

Comparing the effect of VA therapy with music and movement-based physiotherapy

(MMBP) and relaxing music alone on 27 subjects with high muscle tone and

spasticity revealed no significant difference in range of movement between VA

therapy and MMBP, but a significant difference comparing the combined results of

MMBP and VA therapy with relaxing music alone. Additional trials found significant

differences between VA therapy and music alone.

A study on non-clinical subjects (n=39), and a second study (n=52) measured

perceived location of bodily vibrations in response to sinusoidal tones between

20Hz and 70Hz through a VA bed. Reports indicated some that frequencies caused

sensations of resonant vibration consistently in the same places in the body.

A second study on non-clinical subjects (n=60) in three groups found that VA

therapy had a significantly greater effect in reducing arousal when compared with

relaxing music, and a control, and heart rate when VA therapy was compared with a

control. No significant differences were found between the groups in changes in

blood pressure.

A third study (n=60) found no significant differences between four groups when

evaluating the effect of varying rate of amplitude modulation of a 40Hz sinusoidal

tone and a constant tone.

These studies have clarified the efficacy of VA therapy as an intervention for clinical

populations, and the effect of the stimulus on normal subjects. Questions remain

about the nature of the stimulus that is used, and its effect on behaviour.

Keywords: vibroacoustic therapy, music therapy, sound therapy