Comparison of the immediate effects of plantar vibration of both feet with the plantar vibration of the affected foot on balance in patients with stroke: Preliminary findings

OBJECTIVE

Plantar vibration is one of the strategies to enhance balance in stroke patients. This study compared the effects of the plantar vibration of both feet and the plantar vibration of the most affected side in patients with stroke.

METHODS

This study was a single-blind clinical trial. Post-stroke patients with balance impairment were enrolled in the study and underwent two treatment sessions with a one-week interval. They received both feet's plantar vibration in one session and plantar vibration of the most affected side in the other session (frequency 100 Hz, 5 min). Mini-BESTest, Modified Modified Ashworth Scale (MMAS), and Semmes-Weinstein monofilament examination (SWME) were used to evaluate balance, spasticity, and plantar sensation, before and after the treatment sessions.

RESULTS

Ten patients with a mean age of 52.9 (SD = 5.48) years were enrolled in the study. Mini-BESTest scores of balance and plantar flexor muscle spasticity were significantly improved after both feet plantar vibration and plantar vibration of the more affected side. There was no significant difference between the effectiveness of both sides plantar vibration and the most affected side plantar vibration. There were no significant improvements in SWME sensory scores after plantar vibration of either both sides or the most affected side.

CONCLUSION

Plantar vibration of both sides had no additional benefits in this group of patients with chronic stroke. Plantar vibration of more affected side can be used for improving balance and plantar flexor spasticity post-stroke. The Plantar vibration had no effects on the affected foot sensibility.

Acute effects of quadriceps muscle versus tendon prolonged local vibration on force production capacities and central nervous system excitability

PURPOSE

The present study aimed to directly compare the effects of 30 min muscle (VIB_muscle) vs. tendon (VIB_tendon) local vibration (LV) to the quadriceps on maximal voluntary isometric contraction (MVIC) and rate of torque development (RTD) as well as on central nervous system excitability (i.e. motoneuron and cortical excitability).

METHODS

Before (PRE) and immediately after (POST) LV applied to the quadriceps muscle or its tendon, we investigated MVIC and RTD (STUDY #1; n = 20) or vastus lateralis (VL), vastus medialis (VM) and rectus femoris (RF) electromyography responses to thoracic electrical stimulation (TMEPs; motoneuron excitability) and transcranial magnetic stimulation (MEPs; corticospinal excitability) (STUDY #2; n = 17). MEP/TMEP ratios were further calculated to quantify changes in cortical excitability.

RESULTS

MVIC decreased at POST (P = 0.017) without any difference between VIB_tendon and VIB_muscle, while RTD decreased for VIB_tendon (P = 0.013) but not VIB_muscle. TMEP amplitudes were significantly decreased for all muscles (P = 0.014, P < 0.001 and P = 0.004 for VL, VM and RF, respectively) for both LV sites. While no changes were observed for MEP amplitude, MEP/TMEP ratios increased at POST for VM and RF muscles (P = 0.009 and P = 0.013, respectively) for both VIB_tendon and VIB_muscle.

CONCLUSION

The present results suggest that prolonged muscle and tendon LV are similarly effective in modulating central nervous system excitability and decreasing maximal force. Yet, altered explosive performance after tendon but not muscle LV suggests greater neural alterations when tendons are vibrated.

Local plantar vibration for the treatment of diabetic neuropathy: a case report

PURPOSE

One of the most common and debilitating complications of diabetes is peripheral neuropathy. Physical modalities such as whole-body vibration are used to treat diabetic peripheral neuropathy (DPN), but there are limted studies on the effectiveness of local vibration for the treatment of PDN. In this study, we aimed to evaluate the effectiveness of local vibration in treating a patient with DPN.

METHODS

The local vibration was applied on the plantar side of both feet. The patient received 10 min of local vibration with 62.5 Hz frequency for five sessions. We used brief BESTest for balance evaluation, Numerical Pain Rating Scale (NPRS) for pain assessment, monofilament examination score for protective sensation evaluation, vibration threshold, and skin temperature to evaluate the effects of local vibration, which were measured before the treatment, after one session  of treatment, and after 5th session of treatment.

RESULTS

There was a 62.5% reduction in pain severity after five sessions of treatment. Vibration threshold of both patient's feet and protective sensation of right foot returned to normal after treatment. Skin temperature was increased in all evaluated points of both patient's feet, brief BESTest score increased by six points after five treatment sessions, indicating improvements in the blood flow of feet and balance, respectively.

CONCLUSIONS

Local plantar vibration was effective in improving the symptoms of DPN.

Local vibration training improves the recovery of quadriceps strength in early rehabilitation after anterior cruciate ligament reconstruction: A feasibility randomised controlled trial

BACKGROUND

After anterior cruciate ligament reconstruction (ACLR), quadriceps strength must be maximised as early as possible.

OBJECTIVES

We tested whether local vibration training (LVT) during the early post-ACLR period (i.e., ∼10 weeks) could improve strength recovery.

METHODS

This was a multicentric, open, parallel-group, randomised controlled trial. Thirty individuals attending ACLR were randomised by use of a dedicated Web application to 2 groups: vibration (standardised rehabilitation plus LVT, n=16) or control (standardised rehabilitation alone, n=14). Experimenters, physiotherapists and participants were not blinded. Both groups received 24 sessions of standardised rehabilitation over ∼10 weeks. In addition, the vibration group received 1 hour of vibration applied to the relaxed quadriceps of the injured leg at the end of each rehabilitation session. The primary outcome - maximal isometric strength of both injured and non-injured legs (i.e., allowing for limb asymmetry measurement) - was evaluated before ACLR (PRE) and after the 10-week rehabilitation (POST).

RESULTS

Seven participants were lost to follow-up, so data for 23 participants were used in the complete-case analysis. For the injured leg, the mean (SD) decrease in maximal strength from PRE to POST was significantly lower for the vibration than control group (n=11, -16% [10] vs. n=12, -30% [11]; P=0.0045, Cohen's d effect size=1.33). Mean PRE-POST change in limb symmetry was lower for the vibration than control group (-19% [11] vs. -29% [13]) but not significantly (P=0.051, Cohen's d effect size=0.85).

CONCLUSION

LVT improved strength recovery after ACLR. This feasibility study suggests that LVT applied to relaxed muscles is a promising modality of vibration therapy that could be implemented early in ACLR.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT02929004.

Local vibration induced vascular pathological structural changes and abnormal levels of vascular damage indicators

BACKGROUND

The vascular component of the hand-arm-vibration syndrome (HAVS) is often characterized by vibration-induced white fingers (VWF). Active substances secreted by the vascular endothelial cells (VEC) maintain a dynamic balance but damage to the blood vessels may occur when the equilibrium is altered, thus forming an important pathological basis for VWF. This study was aimed at investigating vascular damage indicators as a basis for an early detection of disorders caused by vibration, using the rat tail model.

METHODS AND RESULTS

Experiments were conducted using a control group of rats not exposed to vibration while two exposed groups having different exposure durations of 7 and 14 days were randomly formed. Following exposure, the structural changes of tail tissue samples in anesthetized rats were observed. Enzyme-linked immunosorbent assay (ELISA) was used for analyzing four vascular damage indicators myosin regulatory light chain (MLC2), endothelin-1 (ET-1), vinculin (VCL) and 5-hydroxytryptamine (5-HT) in tail blood samples. We found that both vascular smooth muscle and endothelial cells displayed changes in morphology characterized by vacuolization and swelling in the vibration-exposed group. The levels of vascular damage indicators were altered under the vibration.

CONCLUSION

The degree of vascular pathology increased with the longer duration exposure. Furthermore, the levels of MLC2, ET-1 and 5-HT in rat plasma were associated with vascular injury caused by local vibration.

Immediate Effects of Local Vibration and Whole-body Vibration on Postural Control in Patients with Ataxia: an Assessor-Blind, Cross-over randomized trial

Vibration interventions are used in neurorehabilitation to improve postural control in recent years. Little is known about the immediate effects of vibration interventions on postural control in patients with ataxia. The aim of this study is to investigate and compare the immediate effects of local vibration (LV) and whole-body vibration (WBV) on postural control in patients with ataxia. This study was designed as cross-over, single blind randomized clinical trial. Twenty-one patients with ataxia met the inclusion criteria. LV (frequency, 80 Hz; amplitude, 1 mm) and WBV (30 Hz, 2 mm) were applied to all patients. There was a 1-week washout time between interventions. Each patient was assessed 3 times: pre-intervention and 1 and 60 min post-intervention. The assessor was blinded to the interventions. Outcome measures were limits of stability (LoS), and postural sways (Bertec Balance Check Screener), gait parameters (GAITRite), and static balance (one-leg stance test). Twenty patients completed both interventions. The mean patient age was 39.43 ± 9.67 years. LV increased the left-LoS post-vibration (1 and 60 min post) more than WBV did (p ˂ 0.05). LV increased the LoS stability score and the base of support at 1 min post-vibration, while WBV decreased them (p ˂ 0.05). This study demonstrated different immediate effects of a single session of LV versus WBV and showed that LV has better effects on postural control in patients with ataxia. ClinicalTrials.gov. nr NCT04183647.

Effect of localised vibration on muscle strength in healthy adults: a systematic review

OBJECTIVE

To investigate the effects of local vibration on muscle strength in healthy adults.

DATA SOURCES

The electronic databases PubMed, CINAHL, Scopus and Web of Science were searched using a combination of the following keywords: vibration, vibration therapy, power, maximal voluntary contraction, performance, rate of force development and vibratory exercise. In addition, the Medical Subject Headings 'vibration', 'strength' and 'exercise' were used. The bibliographical search was limited to articles published in English.

STUDY SELECTION

Trials that evaluated the effect of localised vibration on muscle strength in healthy humans were included.

DATA EXTRACTION

Two independent evaluators verified the quality of the selected studies using the PEDro Scale and the Cochrane Collaboration's tool for assessing the risk of bias. Muscle strength was calculated for each intervention.

RESULTS

In total, 29 full-text studies were assessed for eligibility. Eighteen studies did not match the inclusion criteria, and were excluded. The 11 studies included in this review had an average PEDro score of 5.36/10. Most of the studies reported significant improvements in muscle strength after the application of local vibration. There was considerable variation in the vibration training parameters and target muscle location.

CONCLUSIONS

The use of local vibration on the target muscle can enhance muscle strength in healthy adults. Further well-designed controlled studies are required to confirm the effect of local vibration training on muscle strength.

Acute and chronic neuromuscular adaptations to local vibration training

Vibratory stimuli are thought to have the potential to promote neural and/or muscular (re)conditioning. This has been well described for whole-body vibration (WBV), which is commonly used as a training method to improve strength and/or functional abilities. Yet, this technique may present some limitations, especially in clinical settings where patients are unable to maintain an active position during the vibration exposure. Thus, a local vibration (LV) technique, which consists of applying portable vibrators directly over the tendon or muscle belly without active contribution from the participant, may present an alternative to WBV. The purpose of this narrative review is (1) to provide a comprehensive overview of the literature related to the acute and chronic neuromuscular changes associated with LV, and (2) to show that LV training may be an innovative and efficient alternative method to the 'classic' training programs, including in the context of muscle deconditioning prevention or rehabilitation. An acute LV application (one bout of 20-60 min) may be considered as a significant neuromuscular workload, as demonstrated by an impairment of force generating capacity and LV-induced neural changes. Accordingly, it has been reported that a training period of LV is efficient in improving muscular performance over a wide range of training (duration, number of session) and vibration (frequency, amplitude, site of application) parameters. The functional improvements are principally triggered by adaptations within the central nervous system. A model illustrating the current research on LV-induced adaptations is provided.

Effect of the application of local vibration in scaption on joint stability

[Purpose] The aim of this study was to determine the initial effect of local vibration on the stability of the shoulder joints by applying local vibration to the shoulder joints. [Subjects and Methods] For the test, the subjects held a FlexBar with one hand, at about 10 cm from one end, and performed the oscillation movement with the shoulder at 90° flexion and the elbow in the full-extension position in scaption; the vibration stimulus was set to 5 Hz. Then, the subjects underwent the Upper Quarter Y Balance Test to evaluate the stability of the shoulder joints. [Results] The moving distances in the left, right, and upper directions after the oscillation movement were increased significantly compared with the results before the oscillation movement. [Conclusion] A vibration stimulus is effective as an exercise method to increase the stability of the shoulder joints.