After Alzheimer's disease, Parkinson's disease (PD) is the second most common neurodegenerative disease of old age. In addition to pharmacotherapy and possible surgical interventions, the treatment of PD involves physiotherapy, exercise and occupational therapy. Among other things, physiotherapy has been using whole-body vibration (WBV) for several years [Dincher et al., 2021; Peppe et al., 2019]. Vibrations with amplitudes of up to a few millimeters (mm) and frequencies of up to a few tens of hertz (Hz) can have beneficial effects on the neuromuscular system. Thus, many researchers are investigating the use of vibrotherapy in various neurological conditions, including PD [Alashram et al, 2019; Guzik, 2021A; Guzik, 2021B].
The following is a brief review of scientific studies describing the effects of vibrotherapy on the various symptoms of BD, including the vibration parameters used and the methods of administration. The studies show that the use of appropriately selected vibrations has produced positive effects in patients suffering from BD. These effects include:
- improve balance and thus reduce the risk of falls,
- improve motor function,
- reduce pain and stiffness in the limbs,
- increase range of movement and muscle fluidity and strength,
- improve body flexibility (limberness),
- improve quality of life and ability to work.
We encourage you to read the descriptions of the individual studies. Links to the scientific publications discussed can be found below the article.
Vibrotherapy can be an alternative to or enhance conventional therapy in balance rehabilitation
Guadarrama-Molina et al [2021] analysed the effect of vibrotherapy with appropriate vibration parameters (described below) on the functional balance of patients with Parkinson’s disease. They compared vibration therapy with conventional therapy (thermotherapy, stretching, strengthening, coordination) or combined therapy (conventional therapy first, then vibrotherapy). In total, they carried out 20 treatment sessions (three per week) of a given type of therapy.After both conventional therapy, vibrotherapy and combined therapy, they observed a significant improvement in balance when standing or walking compared to the initial assessment. There were no significant differences between conventional therapy and vibrotherapy, but combination therapy produced better results than conventional therapy alone. Therefore, according to Guadarrama-Molina et al [2021], vibrotherapy may be a therapeutic alternative and a useful tool to enhance the effects of conventional functional balance therapy in patients with Parkinson’s disease.
Balance-enhancing vibrotherapy parameters
Guadarrama-Molina et al [2021] used WBV aimed at stimulating the lower limbs and, to a lesser extent, the upper limbs, using tolerable and potentially beneficial (based on previous research) vibration frequencies. The vibration was delivered by a Fitvibe Excel Pro Vibration Trainer vibration platform. The patient stood on the platform in the appropriate position and received vibration at a frequency of 20 Hz and an amplitude of 2 mm. Eight positions were used. The treatment in each lasted 20 s, with subjects resting 30-60 s between positions. The positions were easy and uncomplicated to perform. They included activation of the gluteal muscles, popliteal tendons, quadriceps and triceps muscles – important for stability and posture [Guadarrama-Molina et al., 2021].
Vibrotherapy supports rehabilitation of motor function
Li et al [2021] set out to test the effects of a single administration of WBV on the motor function of people with moderate Parkinson’s disease. They compared these effects with conventional therapy, which consisted of 10 minutes of balance and mobility training.After both WBV treatment and conventional therapy, the scholars reported improvements in motor function. The beneficial effect on the motor function of patients with moderate CHP induced by 1 WBV treatment was neither superior nor inferior to the effects of conventional therapy. According to Li et al [2021], WBV treatments should therefore be considered when planning a passive and safe clinical intervention, especially in patients with motor impairment or balance disorders.
Vibrotherapy parameters to improve motor function
During the vibrotherapy session, five one-minute WBV administrations were used, separated by a one-minute rest. Whole-body administered vibrations, with a frequency of 6 Hz and an amplitude of 3 mm, were delivered by a platform on which participants stood still. They then assumed the following position: head facing forward, slight bending of the knees, feet shoulder-width apart, hands on the safety rails [Li et al., 2021].
Vibrotherapy improves flexibility (suppleness) in patients
Dincher et al [2021] analysed the effectiveness of different vibration frequencies in controlling involuntary stasis (freezing of movement) and in improving flexibility in patients with Parkinson’s disease. As they noted, the effect of WBV on freezing and flexibility has not been studied previously, although the effect of locally administered vibration, or local vibrotherapy, has been investigated.
Well, Winfree et al [2013] achieved a positive effect on stasis using vibrating shoes, and improved flexibility in the hip joint was provided by vibrating cuffs used by Corbett et al [2013] (although vibrating cuffs in the shoulder joint area did not improve shoulder flexibility).
Returning to the study by Dincher et al [2021] regarding WBV, this team of German researchers showed that the WBV they used also improved flexibility. From a range of 6 -18 Hz, it was the higher vibration frequencies (18 Hz) that proved more effective and resulted in a significant improvement in flexibility, as they provided an increase in range of movement in the sit and reach test (by 3.9 cm). However, the vibration therapy parameters used by Dincher et al [2021] did not affect stasis as assessed by the 360° rotation test.
Vibrotherapy parameters to improve flexibility
Dincher et al [2021] used a single application of WBV with a frequency of 6, 12 or 18 Hz and an amplitude of 4 mm. Patients received WBV while standing with their legs slightly flexed on a Galileo med Advanced vibration platform (Novotec Medical). The vibrotherapy treatment consisted of five 60-second series of vibrations, separated by 60-second intervals.
Vibrotherapy improves gait quality, i.e. control of body alignment in time and space
Gait and balance abnormalities in Parkinson’s disease result from damage within motor neuronal pathways, including the associated proprioceptive pathways, which are those that conduct deep sensation from muscles, tendons and joints. The juxtaposition of tensions and stretches of these tissues informs body position and posture. In relation to the known phenomenon of the effects of vibration on proprioception, Peppe et al [2019] evaluated the effects of mechanical vibration on spatial and temporal gait parameters, i.e. the control of the position and movement of one’s own body, in people with moderately advanced Parkinson’s disease.
Using active vibration-generating devices or a placebo, the scientists observed that active vibration stimulation focused on the calves and neck significantly improved various gait parameters, and the beneficial effect increased with increasing Parkinson’s disease symptoms.
- Vibration improved a number of parameters tested, e.g. gait speed (from 0.70 to 0.75 m/s), stride length (from 0.85 to 0.91 m for the right side; from 0.84 to 0.89 m for the left side).
- Vibration reduced disability from 32.57 to 27.25 points on the MDUPDRS III (Parkinson’s Disease Rating Scale). Applied placebo (sham treatments) also reduced MDUPDRS III scores, but to a lesser extent.
- The beneficial effects of vibration depended on the severity of Parkinson’s disease symptoms. Patients with milder symptoms improved by 12.1 %, while patients with slightly more severe symptoms improved by 19.9 % [Peppe et al., 2019].
Vibration therapy parameters to improve gait control
The vibrations were provided by polymer fibres contained in a special plate the size of a postage stamp. This was placed on selected areas on the skin under the patch. These fibres generate vibrations by transforming heat energy from the skin into mechanical energy. Half of the patients wore the small vibration-generating plates taped to their skin for eight weeks. During this time, the remaining patients used a placebo – the same plate, but not generating vibrations. The patients were still taking the established pharmacotherapy, but no other form of rehabilitation. The vibrating or placebo plates were placed on the patients’ skin in areas important in inducing the desired proprioceptive activity (based on previous studies): one above the seventh cervical vertebra, the others – one on each tendon of the hamstring muscle (under the calves). The plates were worn for 6 days per week. In the first week for 1 h, in the second week for 2 h, in the following weeks for 3 and 4 h, respectively. From week 5 to 8, vibration was administered for 4 h per day, 5 days per week [Peppe et al., 2019].
Vibrotherapy improves sensorimotor control of upper limbs of working patients
Epidemiological data show that 30% of all Parkinson’s disease cases are working people. Therefore, Italian researchers from the University of Tor Vergata in Rome [Gentili et al., 2016] analysed the effect of vibration therapy on the rehabilitation of Parkinson’s disease sufferers who are working and in an active and productive phase of life.
The focus was on the ability of people with limb tremor to work and the effect of vibrotherapy on this ability. The study showed that vibrotherapy had a positive effect on hand function and improved quality of life and ability to work, resulting in reduced pain levels, increased range of movement and muscle strength.
- Vibrotherapy improved the motor function of the hand. An increased range of movement, its fluidity and a reduction in stiffness of the whole limb were obtained. Gait was also improved. This had a positive impact on the participants’ working life.
- Wrist mobility increased from 0.29 before vibrotherapy treatments to 5.55 after 10 treatments and remained at 5.00 one month later (UPDRS scale values).
Vibrotherapy parameters to improve sensorimotor control of working patients
Mechanical vibration was provided by a mobile device, generating vibrations through a pneumatic mechanism. Vibrations with an amplitude of 2 mm and a frequency of 30 Hz were used. Vibration was applied topically in 10 sessions (15 min per session), either in the supine position or during physical activity, to specific areas of the upper limb. The areas most affected by stiffness in Parkinson’s disease were selected, namely the palmar surface, ulnar flexor of the wrist, ulnar level of the brachioradialis muscle, posterior part of the biceps brachii muscle and the quadriceps (back) muscle [Gentili et al., 2016].
Vibrating bracelet reduces hand trembling
To conclude this brief literature review, it is worth mentioning one more publication showing a slightly different and very interesting approach to treating the symptoms of Parkinson’s disease – mechanical absorption of the tremor itself.
As noted by Buki et al [2018], limb tremor (observed not only in PD), is a condition characterised by rhythmic and will-independent oscillatory movement. Alternating contraction of flexor and extensor muscles is observed.
Limb tremor affects 4% of the human population over the age of 40 and there is currently no effective cure. Sometimes psychotherapy helps, and usually either pharmacological treatments or invasive (surgical) techniques are used (with varying degrees of success): thalamotomy or deep brain stimulation. As these therapies can generate dangerous side effects, a solution is being sought in the construction of non-invasive devices to attenuate tremor.
Buki et al [2018] decided to test a vibrating bracelet worn on the forearm near the wrist. It is intended to act as a passive absorber of vibrational energy by generating its own vibrations at appropriately adjusted frequencies. The scientists tested prototypes of the vibrating bracelets on a mechanical model of the human forearm. Its vibrations were matched on the basis of hand tremor analysis of 12 Parkinson’s disease patients.
- The 5.85 Hz vibration generated by the vibrating bracelet reduced the tremor of the mechanical forearm, mimicking the vibration observed in the CHP (4 – 5.75 Hz).
- The vibrating bracelet was most effective in suppressing forearm vibrations at 4.75 Hz, reducing the amplitude of these vibrations by up to 86% [Buki et al., 2018].
As noted by Buki et al [2018], dynamic vibration isolators are widely used for vibration control in mechanical and civil engineering. The proposal to use their mechanism of action to attenuate the amplitude of hand tremor seems very interesting. In the study presented here, the vibrating bracelet significantly attenuated the tremor of the mechanical arm, mimicking the tremor observed in CHP, making it appear that it could complement rehabilitation in people suffering from hand tremor.
Hand tremor absorbing bracelet vibration parameters
A device designed to attenuate hand tremor, the vibrating bracelet is designed as a dynamic vibration absorber. Unlike other devices of this type, it is a passive absorber. This means that it does not need an external power supply.
The vibrating bracelet consists of 2 coaxial rings. It derives the energy needed to generate vibrations to counteract forearm tremor from eddy currents generated on the inner surface of the outer ring of the bracelet. The inner ring – directly in contact with the forearm – remains free of electrical voltage. The eddy currents are generated by the presence of magnets placed between the rings. And it is the magnets that are ultimately responsible for magnetically absorbing the vibrations, without providing an external power source.
The vibrating bracelet used weighed 280 g, and its outer radius reached 57 mm. The inner ring of the bracelet was connected to the outer ring via springs. Tuning the described bracelet to the appropriate operating frequency involved modifying the stiffness and width of these springs [Buki et al., 2018].
Summary – vibrotherapy and Parkinson’s disease
As we have outlined in this brief review of the scientific literature on the use of vibrotherapy in supporting the treatment of Parkinson’s disease, different research teams use slightly different ways of administering vibration. Nonetheless, they are quite similar and involve administering vibration systemically (WBV) or to specific muscles or tendons most affected by stiffness in PD (local vibrotherapy).
The frequencies and amplitudes of the vibrations used ranged from 6 to 30 Hz and from 2 to 4 mm, respectively. Vibrotherapy treatments lasted about 10-15 minutes. Single treatments or several weeks’ series of treatments (3-6 treatments per week, 1 per day) were used. No serious side effects of vibration use were reported in any of the cited studies.
It should also be emphasized that the presented publications did not provide specific protocols for rehabilitation of PD using vibrotherapy, but presented scientific studies on various forms of vibration administration that have shown beneficial effects in controlling symptoms of PD. Therefore, they can serve as a starting point in the arrangement by physiotherapists and rehabilitation specialists of appropriate vibrotherapy programs as an adjunctive therapy for Parkinson’s disease.
Summarizing the effects produced by the applied vibrations, both WBV and focused (local) vibration brought improvements in many symptomatological aspects of Parkinson’s disease:
- Have improved balance and reduced the risk of falls,
- Have improved motor functions,
- body flexibility,
- Sensory-motor control of the upper and lower extremities,
- Have reduced pain and stiffness in the limbs,
- increased the range of motion
- and improved occupational functionality among working patients.
Vibrotherapy, although a novel modality in Parkinson’s disease, therefore appears to be such a promising form of physical therapy for PD that its effects should continue to be studied, with particular attention to standardizing therapeutic programs for given groups of patients. Vibrotherapy medical devices usually allow the vibration parameters to be adjusted accordingly, so that they can be optimally adapted to a given case, or have predefined therapeutic programs, and we encourage patients to test them, of course, as with any form of therapy, under the guidance of physiotherapists or rehabilitation physicians.
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