Vibrotherapy reduces upper limb spasticity in post-stroke patients

Vibrotherapy assists traditional exercise methods of the upper limbs in improving their function. The use of mechanical vibration has resulted in a reduction in spasticity and an increase in maximum grip strength in people with post-stroke haemiplegia.

The loss of motor function of the hand results in a lack or reduced ability to grip. One of the most important therapeutic therapies used after a stroke is physical activity. Vibrotherapy causes neuromuscular adaptations similar to the effect induced by strength training. This provides a rationale for the use of mechanical vibration in neuromuscular training used to increase muscle strength in a clinical setting. The aim of the study described here was to investigate the effect of vibration therapy combined with hand exercises on spasticity and maximal grip strength in patients after haemiplegic stroke.

• Vibrotherapy in combination with additional hand exercises improves the hand’s motor skills. The results of the motor function test (Fugl-Meyer upper extremity test) were significantly better in the group with vibrotherapy and in the group with vibrotherapy and exercise than in the control group (control group change of 3.22, group with vibrotherapy change of 12.65, group with exercise and vibrotherapy change of 15.66).
• Arm movements involving more difficult movements, i.e. interacting with objects (lifting a drinks can, stacking a checker and folding a towel) significantly improved in patients using vibrotherapy in combination with exercise (Wolf Motor Function test improvement of 14 points).
• The greatest decrease in spasticity was noted after vibrotherapy combined with hand exercises.
• Vibrotherapy combined with hand exercises resulted in a 31% increase in hand grip strength.

Based on:

Short-Term Effects of Whole-Body Vibration Combined with Task-Related Training on Upper Extremity Function, Spasticity, and Grip Strength in Subjects with Poststroke Hemiplegia A Pilot Randomized Controlled Trial.
Jung-Sun Lee, Chang-Yong Kim, Hyeong-Dong Kim. American Journal of Physical Medicine & Rehabilitation,
01 Aug 2016, 95(8):608-617

Forty-five people (21 women and 24 men) participated. Stroke diagnosis and lesion location were based on computed tomography or magnetic resonance imaging, as well as examination of neurological function. Inclusion criteria for the study were: completion of post-stroke rehabilitation six to 18 months previously, hemiplegia after ischaemic or haemorrhagic stroke, a score of at least 26 on the Brief Mini – Mental State Examination, no excessive spasticity in the affected arm, Brunnstrom Scale grade III or higher in the proximal and distal arms, and no pain in the affected limb. Subjects with musculoskeletal abnormalities, confusion, neurological disorders or unilateral neglect were excluded from the study.

Research procedure

Changes in upper limb functional performance and motor control were assessed using clinical and maximum grip strength assessments. Testing was performed before and after a 4-week intervention period.

The degree of upper limb motor impairment was assessed using the Fugl-Meyer upper extremity test. A physiotherapist assessed the normality of 30 voluntary upper limb movement patterns with a 3-point ordinal scale and tested the excitability of 3 tendons with a 2-point ordinal scale. A higher score indicated better motor skills.

The Wolf Motor Function Test (WMFT Wolf Motor Function test) was used as a quantitative indicator of upper limb motor abilities that could be tested using timed and action tasks. In this test, subjects performed activities that included more difficult arm movements and interactions with objects, such as lifting a drinks can, stacking a checkerboard and folding a towel. Higher scores representing greater upper limb motor ability.

The Ashworth Scale (MAS) was used to assess hand spasticity. The test involves passive movement, during which the quality of this movement is assessed. The extent of spasticity was measured for eight muscle groups, including the shoulder, elbow and wrist and hand muscles.

Maximum hand grip force was measured using a calibrated Jamar hydraulic hand dynamometer. The position of the dynamometer was adjusted to the size of the subject’s hand. The subjects performed the test while sitting on a bed or chair with the elbow bent at 90 degrees and the wrist neutrally positioned. The mean of 3 trials of maximum grip strength for the paralysed and healthy hand was used for assessment. The maximum grip strength of the paralysed hand was normalised with that of the healthy hand.

Study participants were randomly allocated to three study groups: a control group, a group with applied vibration therapy and a group with vibration therapy and rehabilitation exercises with different objects. During an experiment lasting 4 weeks, the subjects in the control group performed conventional upper limb training for 1 hour a day 3 times a week. This included training of activities of daily living, training of movement patterns and range of motion. Patients in the group with vibration therapy included received half an hour of daily conventional upper limb training, followed by vibration training for half an hour daily, 3 days a week. In the third study group, patients received half an hour of vibrotherapy and exercise with objects of different weights and shapes for half an hour daily 3 days a week. Exercise effects were measured before and after the 4-week study period.

The use of vibrotherapy in research

In the vibrotherapy group, alternating vertical sinusoidal vibration with a frequency of 5 to 15 Hz, and an amplitude of 1 to 6 mm was applied. The subjects sat on a vibration platform chair with their hands placed on the platform board.

Results

There was an improvement in upper limb motor function in each study group, with the final Fugl-Meyer upper extremity test scores being significantly better in the vibration therapy group and the vibration and exercise group (control group from 31.17±13.23 to 34.39±12.54, vibration therapy group from 30.58±14.21 to 43.23±13.98, exercise and vibration therapy group from 30.08±11.05 to 45.74±12.11). A motor function test including more difficult arm movements WMFT (Wolf Motor Function test) scored best in the vibrotherapy plus exercise group from 39.06 ± 16.35 to 53.07 ± 17.25 and was significantly higher than the scores in the other groups. In the vibrotherapy with exercise group, all Ashworth Scale (MAS) scores were significantly lower for than the other groups (control group from 18.29±5.74 to 15.08±3.90, vibrotherapy group from 17.77±6.42 to 14.21±3.01, exercise and vibrotherapy group from 17.98±4.09 to 8.27±1.79). Hand grip strength improved by 31% in the vibrotherapy and exercise group. This result was significantly better than the results obtained in the other study groups.

Skala VAS – VAS scale of pain; przed terapią – before the therapy; po terapii – after the therapy; ćwiczenia i wibroterapia – exercises and vibrotherapy; wibroterapia – vibrotherapy; grupa kontrolna – control group.

Comment

Upper limb function in people with post-stroke hemiparesis depends on the severity of the paresis, the degree of spasticity, and the extent of motor and sensory loss. This is manifested by loss of hand function such as grip, among other things. In prolonged spasticity, changes in the periarticular connective tissue lead to shortening of the muscles and connective tissue, resulting in reduced functionality of the upper limb. Vibrotherapy has proven to be an effective method of improving hand function and decreasing hand spasticity and, when combined with additional exercises, enhances the effect of the therapy.

A good indicator of overall hand strength and neuromuscular function is the measurement of maximum hand grip strength, which is indirectly related to functional autonomy and thus quality of life. In the study described here, vibrotherapy combined with exercise effectively improved maximum grip strength. In addition, to avoid the influence of age on the results, the hand strength on the paresis side was normalised with that of the healthy hand.

The use of vibration therapy (vibration platforms) can be a training complementary therapy in people with hemiplegia. The benefits of such measures are comparable to those of resistance training in post-stroke patients. It can therefore be assumed that the application of low-frequency vibration stimuli to paralysed muscles results in activation of the ends of the primary muscle spindles. The results of the described studies show an increase in motor skills and a decrease in spasticity of the upper limb with the use of vibration therapy and hand exercises. Such significant results were not obtained with vibrotherapy alone. Therefore, hand exercises, i.e. reaching, grasping and throwing balls, facilitate a smooth transition to different upper limb movements, thereby reducing spasticity and increasing upper limb motor skills. The therapeutic approach proposed in this study may be a novel neurological rehabilitation strategy for patients with varying degrees of upper limb paralysis.

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