Therapeutic vibrations: functions and the latest advances in medical applications

The vibrations that surround us can be detected using sensitive skin mechanoreceptors. Strong vibrations can be harmful, but milder can have a positive effect on health, although the extent of this effect is still controversial. Whole-body vibration (WBV) can be provided, for example, by vibration platforms, used both in animal and human research. The presented review describes the mechanisms related to the perception of vibrations and the way of using vibrations in medicine in the form of vibrotherapy and its specific type – WBV.

• Since 2009, scientists in many countries have been studying the effects of WBV on: body composition, quality of life, pain management, morphology, circulation and tissue flow, musculoskeletal, pulmonary, and neurological functions, diabetes, osteoporosis, treatment of cancer, multiple sclerosis, Parkinson or Alzheimer Disease, the rehabilitation of cerebral palsy and the healing of fractures.
• WBV has great potential in sport and medical applications, but,
• especially as a form of therapy, WBV requires further research on their effectiveness, however conducted in a standardized (and personalized) manner between research centers.

Prepared on the basis of:

Vibration detection: its function and recent advances in medical applications [version 1; peer review: 2 approved]. Oroszi T, van Heuvelen MJG, Nyakas C and van der Zee EA.  F1000Research 2020, 9(F1000 Faculty Rev):619

Vibration sensitivity is present even in the simplest life forms. In the animal kingdom, the sense of vibration is used, among others, for prey detection, avoiding predators or for navigation. Humans have a high density of mechanoreceptors in the skin to detect vibrations. To a lesser extent they are also found in ligaments, joints, blood vessels, and organs. Mechanoreceptors through the spinal cord and then the thalamus send projections to the somatosensory cortex, where different cortical regions of the brain are involved in processing information about vibrations.

Vibrations can be harmful, especially when the amplitude exceeds 1 mm, and the application time exceeds approx. 30 minutes and the vibrations are irregular/ random. Moreover, since each part of the body exhibits its own natural vibrations (internal resonance frequency), this should also be taken into account when designing safe vibrotherapy programs. Resonant frequencies could be more effective, but must be controlled in strict safe application time limits. For example, the abdominal resonant frequency is 4-8 Hz, the chest – 5-10 Hz, and the head – 20-30 Hz. The type of vibration also matters, but also the positioning of the person undergoing vibrotherapy.

Indirectly, the therapeutic potential of WBV can be evidenced by the history of publications in the field. As attention shifted from harmful to beneficial effects of vibrations, the number of publications on WBV began to increase (Fig. 1). Since around 2009, scientists have been studying the effects of WBV on body composition, quality of life, pain management, morphology, circulation and tissue flow, musculoskeletal, pulmonary, and neurological functions, diabetes, osteoporosis, treatment of cancer, multiple sclerosis, Parkinson or Alzheimer Disease, the rehabilitation of cerebral palsy and the healing of fractures.

Comment

Vibrotherapy, including WBV, is still an emerging discipline of medical science, but already has clear potential for sports and therapeutic applications. It seems obvious that in order to make the best use of the therapeutic potential of WBV, research in this field should be properly conducted. Since animal and in vitro studies are feasible, the use of translational studies may facilitate understanding of mechanisms and delivery of appropriate WBV protocols. The key in proper implementation of research on WBV is the reliable presentation of the so-called “big five” WBV: vibration amplitude and frequency, methods of their application, duration of a single session and frequency of sessions, and the total duration of the intervention.Many systematic reviews of WBV are summarized in that the findings are promising but inconclusive. This is mainly due to the high variability of the applied vibration parameters between research centers and incomplete reporting of methodological details that hinder the repeatability of tests. A step forward will undoubtedly be the forthcoming update of the Reporting Guideline for WBV Therapeutic Effects Research {this update has just been published – see “Guidelines for conducting research on whole body vibration as a form of training or medical treatment”; editorial note}.

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