Fibromyalgia (FM) is a chronic disorder of unknown aetiology. It is characterised by widespread noninflammatory pain and tenderness that persists for at least 3 months and by an acute response in at least 11 of 18 specified tender points when these points are digitally palpated with a pressure of 4 kg/cm2 [
In European populations (Spain, Portugal, France, Germany, and Italy), the estimated overall prevalence of FM is between 2.9% and 4.7% [
Several therapies have been used to treat the symptoms associated with FM, including pharmacological and nonpharmacological therapies. There is strong evidence showing that both pharmacological and nonpharmacological approaches can be effective [
WBV can be delivered by two types of exercise platform. One is a sinusoidal vibration device that induces reciprocal vertical displacements on the left and right sides of a fulcrum and generates higher lateral acceleration than vertical acceleration. The second is a vertical vibration device that induces up-and-down oscillations over a vertical axis and produces high strain in the vertical axis [
Some studies suggested that WBV therapy may improve balance, pain, and fatigue. The mechanisms behind these effects are not clear but may relate to the following. WBV elevates heart rate and oxygen uptake, which could translate to improved cardiorespiratory fitness over the long term [ WBV may influence the neuromuscular system and improve reflex responses, especially in patients who have altered reflex generation. This may be related to the ability of vibration to (a) stimulate subcutaneous proprioceptors, (b) activate muscle spindles, thereby causing muscle contraction, and (c) stimulate Golgi tendon organs, thereby improving tonic and antagonist vibration reflexes [ WBV may reduce the perception of pain because vibration affects the afferent discharge of fast adapting mechanoreceptors and muscle spindles [
Potential harmful effects of vibration exposure have been found in industrial workers, and vibration is recognised as an industrial hazard. Prolonged exposures can induce vascular and neurological injuries, and legal limits have been set in numerous countries [
To our knowledge, there is one review that examined the effect of WBV therapy on FM-associated symptoms [
Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology was employed to carry out this systematic review [
To locate the articles reported in this systematic review, four well-known electronic databases were selected, and a list of terms and compounded terms was prepared. These activities were supervised by medical library science experts and experts in the field of WBV in FM. The databases were the Cochrane Library (2003–present), the Physiotherapy Evidence Database (PEDro; 2003–present), PubMed (1973–present), and TRIP (2002–present). The articles were located using the keywords “fibromyalgia” and “vibration” and the Boolean operator “AND”. Duplicate articles were manually removed by one of the authors.
Figure
Flow chart delineating the complete systematic review process that was followed.
The PEDro scale was used to assess the risk of bias in the selected articles. This is a scale that rates the methodological quality of RCTs that evaluate physical therapist interventions. This scale was chosen because of its special design and capacity to provide a global overview of the external and internal validity of the studies [
Risk of bias and level of evidence.
Clinical trial | Reference | Response to each item on the PEDro scale | Level of evidence | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | Total score | |||
Alentorn-Geli et al. | [ |
y | y | n | y | y | n | y | y | n | y | Y | 7 | B |
[ |
y | y | n | y | y | n | n | y | n | y | Y | 6 | B | |
|
||||||||||||||
Gusi et al. | [ |
y | y | y | y | n | n | y | y | y | y | Y | 8 | B |
[ |
y | y | y | y | n | n | y | y | y | y | Y | 8 | B | |
[ |
y | y | y | y | n | n | y | y | n | y | Y | 7 | B | |
|
||||||||||||||
Sañudo et al. | [ |
y | y | y | y | n | n | n | y | n | y | Y | 6 | B |
[ |
y | y | y | y | n | n | n | y | n | y | Y | 6 | B | |
|
||||||||||||||
Sañudo et al. | [ |
y | y | y | y | n | n | n | y | y | y | Y | 7 | B |
n: criterion not fulfilled; y: criterion fulfilled; 1: eligibility criteria were specified; 2: subjects were randomly allocated to groups or to a treatment order; 3: allocation was concealed; 4: the groups were similar at baseline; 5: there was blinding of all subjects; 6: there was blinding of all therapists; 7: there was blinding of all assessors; 8: measures of at least one key outcome were obtained from more than 85% of the subjects who were initially allocated to groups; 9: intention-to-treat analysis was performed on all subjects who received the treatment or control condition as allocated; 10: the results of between-group statistical comparisons are reported for at least one key outcome; 11: the study provides both point measures and measures of variability for at least one key outcome; total score: each satisfied item (except the first) contributes 1 point to the total score, yielding a PEDro scale score that can range from 0 to 10. B: the level of evidence was B (randomised control trials that lacked double-blinding) (see the Appendix).
The level of evidence was determined using the guidelines of the Dutch Institute for Healthcare Improvement (CBO) [
Data were extracted from the selected articles by one of the authors. This extraction was checked by another author. Any disagreement was discussed and ultimately resolved by a third author if the contact with the original author of the article could not be established.
For each selected article, the following data were extracted: (a) the sample and protocol characteristics, namely, the sample size, age, and activity of the control and WBV groups (Table
Sample characteristics and protocol.
Clinical trial | Sample characteristics | Protocol | ||||
---|---|---|---|---|---|---|
Reference | Total sample size ( |
Age of whole cohort (mean ± SD) (years) | Treatment of the control group(s) | Treatment of the vibration group | WBV protocol | |
Alentorn-Geli et al. | |
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|
Static and dynamic tasks on a vibratory platform with vibratory stimulus: |
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Gusi et al. | |
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The stance of the participants on the platform alternated between the following: (a) feet placed perpendicular to the midline axis of the platform, with the right foot positioned slightly ahead of the left foot. The toes of the right foot and the heel of the left foot were then lifted 4 mm above the surface of the platform. The knees were bent and maintained at a 45° knee angle. (b) Feet were placed perpendicular to the midline axis of the platform, with the left foot positioned slightly ahead of the right foot. The toes of the left foot and the heel of the right foot were lifted 4 mm above the surface of the platform. The knees were bent and maintained at a 45° knee angle |
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Sañudo et al. | [ |
26* |
59 ± 7.9 |
Physical exercise | Physical exercise plus WBV protocol | Three sets of 45 s performed with both feet in contact with the platform and four sets of 30 s with only one foot in contact with the platform (15 s per foot). In each set, the participants stood with both knees in 120° isometric knee flexion |
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Sañudo et al. | [ |
46** | 57.15 ± 6.8 | Physical exercise | Physical exercise plus WBV protocol | Six sets of 30 s performed with both feet on the platform and four sets of 60 s with only one foot in contact with the platform (30 s per foot) |
CG: control group; EG: exercise group; *
WBV therapy and activity.
Authors | Freq. (Hz) | Amp. (mm) | Vibration device | Type of vibration | Duration (weeks) | Number of sessions | Number of series | Time series (s) | Rest between series (s) |
---|---|---|---|---|---|---|---|---|---|
Alentorn-Geli et al. [ |
30 | 2 | Power Plate | Vertical sine wave | 6 | 12 | Three in the first two sessions |
30 | 180 |
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Gusi et al. [ |
12.5 | 3 | Galileo | Horizontal sine wave | 12 | 36 | 6 | 30 s in sessions 1–4 |
60 |
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Sañudo et al. [ |
20 | 3* |
Galileo | Horizontal sine wave | 6 | 18 | 3* |
45* |
120 |
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Sañudo et al. [ |
30 | 4 | Power Plate | Vertical sine wave | 8 | 24 | 6* |
30* |
45 |
Freq.: frequency; Amp.: amplitude.
*With both feet in contact with the platform; **With one foot in contact with the platform.
Figure
Table
Table
Level of conclusion according to the Dutch CBO guidelines.
Outcome measure | Level of conclusion |
---|---|
Balance | 2 |
Quality of life | 2 |
Serum insulin-like growth factor-1 | 3 |
Strength | 3 |
Fatigue | 2 |
Pain | 3 |
Depression | 3 |
Stiffness | 3 |
Disability index (fibromyalgia impact questionnaire) | 2 |
CBO: Institute for Healthcare Improvement.
Level 2: one trial of level A2 or at least two independent trials of level B (see the Appendix); 3: one trial of level B or C (see the Appendix).
Tables
Outcome measures.
Authors | Reference | Instrument | Outcome measure | CG baseline | CG after treatment | EG baseline | EG after treatment | Treatment effect | Reported effect |
---|---|---|---|---|---|---|---|---|---|
Alentorn-Geli et al. |
[ |
ELISA | IGF-1 | NR | NR | NR | NR | NR | = |
[ |
FIQ | Functional capacity | NR | NR | NR | NR | NR | Δ | |
100 mm VAS | Pain | NR | NR | NR | NR | NR | Δ ↑ | ||
Fatigue | NR | NR | NR | NR | NR | Δ ↑ | |||
Stiffness | NR | NR | NR | NR | NR | ↑ | |||
Depression | NR | NR | NR | NR | NR | = | |||
|
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Gusi et al. |
[ |
FIQ | Functional capacity | 53.6 ± 12.3 |
57.5 ± 11.2 |
59.3 ± 9.8 |
56.7 ± 11.1 |
−6.42 |
↑ |
15D questionnaire | Quality of life | 0.65 ± 0.1 | NR | 0.63 ± 0.1 | NR | NR | = | ||
[ |
Biodex Balance System | Dynamic balance | 1.47 ± 0.55 |
1.51 |
1.49 ± 0.67 |
0.85 |
−0.69 |
↑ | |
[ |
Biodex Balance System | SB overall SI (°) | 1.36 ± 0.50 | 1.40 ± 0.50 | 1.53 ± 0.56 | 0.88 ± 0.41 | −0.65 | ↑ | |
SB anteroposterior SI (°) | 0.80 ± 0.29 | 0.96 ± 0.47 | 1.05 ± 0.49 | 0.56 ± 0.31 | −0.64 | ↑ | |||
SB mediolateral SI (°) | 0.94 ± 0.37 | 0.83 ± 0.26 | 0.88 ± 0.37 | 0.55 ± 0.22 | −0.19 | = | |||
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Sañudo et al. |
[ |
T-Force Dynamic Measurement System | Knee extensor strength | 207.4 ± 16.5 | 202.6 ± 13.6 | 208.2 ± 16.7 | 210.7 ± 18.1 | 7.3 | = |
Biodex Balance System | OE overall SI | 7.50 ± 3.07 | 6.47 ± 2.98 | 6.63 ± 3.23 | 5.5 ± 2.67 | −0.1 | = | ||
OE mean deflection | 6.25 ± 2.93 | 5.63 ± 2.86 | 5.52 ± 2.87 | 4.66 ± 2.55 | −0.2 | = | |||
OE anteroposterior SI | 5.42 ± 2.13 | 5.33 ± 2.68 | 4.97 ± 2.45 | 4.76 ± 2.81 | −0.1 | = | |||
OE anteroposterior mean deflection | 2.93 ± 1.37 | 3.48 ± 2.64 | 2.90 ± 1.79 | 3.60 ± 2.81 | 0.2 | = | |||
OE mediolateral SI | 5.07 ± 2.57 | 3.35 ± 1.97 | 4.34 ± 2.32 | 2.49 ± 1.09 | −0.1 | ↑ | |||
OE mediolateral mean deflection | 1.61 ± 1.18 | 1.23 ± 0.93 | 1.28 ± 1.04 | 1.17 ± 0.75 | 0.3 | = | |||
CE overall SI | 11.67 ± 2.41 | 11.37 ± 2.32 | 11.9 ± 2.16 | 10.7 ± 2.64 | −0.9 | = | |||
CE mean deflection | 10.35 ± 2.25 | 9.90 ± 2.30 | 10.51 ± 2.14 | 9.26 ± 2.57 | −0.8 | = | |||
CE anteroposterior SI | 8.97 ± 1.88 | 8.86 ± 2.40 | 9.37 ± 2.25 | 8.75 ± 2.93 | −0.5 | = | |||
CE anteroposterior mean deflection | 4.12 ± 2.41 | 3.74 ± 2.28 | 4.25 ± 2.36 | 5.01 ± 3.71 | 1.1 | = | |||
CE mediolateral SI | 7.37 ± 2.30 | 6.25 ± 2.05 | 7.47 ± 1.28 | 5.56 ± 1.38 | −0.8 | ↑ | |||
CE mediolateral mean deflection | 2.55 ± 1.49 | 2.01 ± 1.33 | 2.75 ± 1.31 | 2.01 ± 1.34 | −0.2 | = | |||
[ |
FIQ | Functional capacity | 56.66 ± 11.58 | 49.81 ± 14.87 | 48.89 ± 12.08 | 43.79 ± 12.31 | 1.7 | Δ# | |
SF-36 | Quality of life | 33.58 ± 12.10 | 42.51 ± 11.30 | 44.16 ± 18.88 | 54.00 ± 15.83 | 0.9 | Δ↑# | ||
T-Force System | Maximum power of knee extensor muscles | 80.92 ± 24.17 | 85.01 ± 19.73 | 81.29 ± 28.34 | 87.05 ± 19.72 | 1.7 | = | ||
Number of repetitions | 22.08 ± 9.21 | 24.71 ± 6.26 | 23.75 ± 7.87 | 28.71 ± 5.25 | 2.3 | Δ | |||
Muscular fatigue index | 0.91 ± 0.14 | 0.96 ± 0.05 | 0.90 ± 0.06 | 0.97 ± 0.17 | 0.0 | = | |||
|
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Sañudo et al. |
[ |
Biodex Stability System | OE overall SI | 5.53 (1.49) | 6.10 (1.40) | 7.02 (3.66) | 5.75 (2.51) | −1.84 | = |
OE mean deflection | 4.58 (1.32) | 4.99 (1.16) | 5.85 (3.18) | 4.67 (2.09) | −1.59 | = | |||
OE anteroposterior SI | 4.46 (1.36) | 5.03 (1.21) | 5.36 (2.90) | 4.92 (2.18) | −1.01 | = | |||
OE anteroposterior mean deflection | 2.18 (1.67) | 2.40 (1.08) | 2.47 (2.24) | 2.48 (1.29) | −0.21 | = | |||
OE mediolateral SI | 3.35 (1.17) | 3.83 (1.37) | 4.54 (2.56) | 2.94 (1.44) | −2.08 | Δ↑ | |||
OE mediolateral mean deflection | 1.23 (1.66) | 0.76 (0.19) | 2.28 (1.08) | 1.31 (0.21) | −0.5 | ↑ | |||
CE overall SI | 9.31 (1.83) | 8.89 (1.95) | 9.91 (3.64) | 9.10 (2.99) | −0.39 | = | |||
CE mean deflection | 7.90 (1.77) | 7.63 (1.80) | 8.43 (3.55) | 7.76 (2.83) | −0.4 | = | |||
CE anteroposterior SI | 7.31 (1.93) | 7.30 (1.84) | 7.68 (2.58) | 7.32 (2.47) | −0.37 | = | |||
CE anteroposterior mean deflection | 3.21 (2.66) | 3.87 (2.38) | 1.90 (2.01) | 3.18 (2.27) | 0.62 | = | |||
CE mediolateral SI | 5.81 (1.49) | 5.21 (1.21) | 6.39 (2.86) | 5.48 (2.03) | −0.31 | Δ | |||
CE mediolateral mean deflection | 1.62 (1.02) | 0.95 (0.84) | 1.09 (0.87) | 1.80 (1.02) | 1.38 | = | |||
T-Force System | Number of repetitions | 23.72 (7.98) | 23.50 (6.63) | 30.85 (8.90) | 31.14 (7.18) | 0.51 | = |
CG: control group; EG: exercise group; NR: not reported; ELISA: enzyme-linked immunosorbent assay; IGF-1: serum insulin-like growth factor-1; FIQ: fibromyalgia impact questionnaire; SB: static balance; VAS: visual analogue scale; OE: open eyes; CE: closed eyes; SI: stability index; =: no significant difference relative to baseline and/or the control group;
*Intention-to-treat analysis.
Two RCTs used the Power Plate vibratory platform [
Power Plate and Galileo vibration platforms.
The four RCTs differed in terms of the amplitude and frequency of the vibration. The two RCTs that used the horizontal sine-wave vibration employed an amplitude of 2-3 mm and a frequency of 12.5–20 Hz, and the two RCTs that used the vertical sine-wave vibration employed an amplitude of 2–4 mm and a frequency of 30 Hz.
The postures used in the four RCTs also varied. In three RCTs, patients maintained a static posture on the platform during vibration [
All four RCTs sought to analyse the long-term effects of WBV therapy. In two of the three RCTs, 6 weeks of WBV therapy were performed [
The measurements with the highest level of conclusion (Table
Three of the RCTs [
One study showed that WBV significantly improved the dynamic balance of the WBV group compared to the control group [
Two studies assessed HRQoL [
Three of the RCTs assessed the effect of WBV therapy on fatigue [
In one study, WBV improved fatigue relative to both baseline and the control group [
The disability caused by FM was assessed in three RCTs using the Spanish version of the FIQ [
In one RCT [
Pain is the most important symptom in FM, but it was assessed specifically in only one study, which reported an improvement in pain compared to both baseline and the control groups [
The four RCTs revealed that WBV therapy may improve several symptoms of FM, namely, disability, pain, poor HRQoL, poor balance, and fatigue.
The duration of the treatment could be extremely relevant when assessing the effects of WBV on disability caused by FM. Two RCTs only involved 6 weeks of complementary vibration therapy, and one RCT involved 12 weeks of vibration therapy. This latter RCT reported a significant improvement in FIQ score relative to the control group, whereas the other two RCTs only reported within-group improvements. It may be that the effect of WBV therapy on FIQ score can only be observed with longer treatments.
With regard to pain, the single study examining this outcome used the 100 mm VAS to show that WBV therapy significantly improved pain compared to both baseline and the control groups [
There were large differences in treatment effects on balance. These discrepancies may reflect differences between the WBV protocols. Effects of the two vibratory platforms (Galileo and Power Plate) on balance were compared by Sañudo et al. [
With regard to fatigue, Sañudo et al. compared the two vibratory platforms with the same protocol. They found that only the Galileo platform induced a significant improvement in the number of repetitions of a half squat exercise performed in 60 s. However, it cannot be concluded that these improvements were due to an improvement in cardiorespiratory fitness. Devices that assess oxygen consumption in a more objective way must be used to evaluate this measure.
Three RCTs yielded five articles [
The differences between studies in the effect of WBV on balance [
The four RCTs differed markedly in terms of important characteristics, namely, the type of vibration (vertical or horizontal sine wave), the type of therapy (vibration or exercise + vibration), and the vibration protocol (frequency, amplitude, time series, rest interval, and duration). Therefore, additional studies that assess the effect of WBV in different settings are needed. These studies should compare (a) different protocols with the same device and the same type of therapy, (b) different devices with a similar protocol and the same type of therapy, and (c) different types of therapies with the same device and the same protocol. These studies will identify the optimal characteristics of vibration therapy that are needed to improve functional capacity, HRQoL, balance, and other key symptoms of FM.
To our knowledge, the acute effects of WBV on FM symptoms have not been assessed by any study. However, a study on patients with low back pain showed that a single WBV session induced statistically significant within-group changes in lumbopelvic pain perception [
The present systematic review only identified a limited number of studies on the effects of WBV therapy on FM. This reflects the fact that the RCTs on this issue only started very recently; the first completed study was published in 2008. The small number of trials together with their wide variation in terms of PICOS (Participants, Intervention, Control, Outcome Measurements, and Study design) hampers meta-analysis. This explains why the CBO guidelines [
There are several limitations that should be considered. First, standardised criteria to assess the level of evidence are needed. Authors of systematic reviews often use different criteria [
As emphasised in the Introduction, FM entails a huge cost to governments. Therefore, studies on the cost-effectiveness and utility of WBV as a therapy in a condition that is as prevalent and widespread as FM are needed.
WBV may be an adequate treatment for FM as a main therapy or when added to a physical exercise programme as it could improve the balance, disability index, quality of life, fatigue, and pain of patients with FM. However, the small number of RCTs on WBV in FM and their wide variation in terms of vibration protocol, intervention, and measurements hampered our comparison of these trials. Additional studies that definitively clarify the effects of WBV therapy on FM are needed.
systematic review containing at least two independent trials of level A2; randomised comparative double-blind study of good quality and sufficient size; comparative trials, but not all characteristics of A2 (also, patient control studies and cohort studies); noncomparative trials; expert opinion.
research on level A1 of at least two independent trials of level A2; one trial of level A2 or at least two independent trials of level B; one trial of level B or C; expert opinion.
CBO: Institute for Healthcare Improvement.
The authors declare that there is no conflict of interests regarding this paper.
In the framework of the Spanish National R + D + i Plan, the current study was cofunded by the Spanish Ministry of Economy and Competitiveness with the Reference DEP2012-39828. This study was also cofunded by the Government of Extremadura and European Union Regional Development Funds (FEDER), a way of making Europe (Reference GR10127). The author Daniel Collado-Mateo is a predoctoral student funded by the foundation “Tatiana Pérez de Guzmán el Bueno.”