This study evaluated the effects of whole-body vibration (WBV) com-bined with action observation on gross motor function, balance, and gait in children with spastic cerebral palsy. The participants were randomized into the WBV combined with action observation (WBVAO) group (n=7) and the WBV group (n=7). The WBVAO group received WBV combined with action observation training, and the WBV group received WBV training for 4 weeks. Both groups received 30 min of training a day, 3 times a week. All participants completed the 5 times sit to stand (FTSTS) test, Timed Up and Go (TUG) test, pediatric reach test, 10-m walk test, 6-min walk test (6MWT), and timed up and down stair (TUDS) test before and after the training intervention. Moreover, the participant’s Gross Motor Function Measure (GMFM) and Pediatric Balance Scale (PBS) scores were assessed. Both the WBVAO and WBV groups demonstrated significant increases in the scores of FTSTS test, GMFM (D and E dimensions), PBS, TUG test, 6MWT, and TUDS test. The WBVAO group improved more significantly compared to the WBV group based on the scores of the FTSTS test, GMFM (D dimension), PBS, 6MWT, and TUDS test. WBV combined with action observation improved lower extremity functional strength, gross motor function, and balance and gait in children with cerebral palsy. These results suggest that WBV combined with action observation is both feasible and suitable for individuals with cerebral palsy.
Cerebral palsy (CP) can be categorized according to the level of motor disturbance and the sites affected, with the spastic type being the most common (
Among these training techniques, WBV training is considered to be a safe and effective method. WBV was recently introduced as a novel way to improve proprioceptive sense, bone density, balance, and motor skills (
Motor learning is the ability to flexibly adapt to the environment when acquiring and performing motor techniques (
Children diagnosed with spastic CP and admitted at the National Transportation Rehabilitation Hospital, which is located in the Yangpyeong, Gyeonggi Province of Korea, participated in the study. Children with the following characteristics were included in the study: children aged 4–12 years who were diagnosed with spastic CP, children with no visual impairments, children who could respond to instructions provided by the researchers, and children with gross motor function categorized as levels 1–3 based on the Gross Motor Function Classification System Scale (GMFCS). Conversely, children with the following characteristics were excluded: children with scores >2 in the Modified Ashworth scale in their effected limb, children experiencing joint contracture, children who had experienced seizure within the past 6 months, or children with conditions that could not be controlled despite seizure medication. Finally, 14 participants were allocated randomly to the WBV combined with action observation (WBVAO) group (n=7) or the WBV group (n=7). This study protocol was approved by the Sahmyook University Institutional Review Board (2-1040781-AB-N-01-2016031HR), and the objective of the study and its requirements were explained to the participants. Written parental consent was provided for all of the participants; therefore, the rights of the human participants were protected.
Sixteen children who were receiving weekly or outpatient rehabilitation treatment from National Transportation Rehabilitation Hospital for their spastic CP were selected. Two of these 16 children were excluded from the study considering that their GMFCS scores were <3. To minimize any bias during selection, a stratified sampling method based on age and GMFCS stage was used. The number of children with CP who visited the hospital was small sample size and we could not make a control group without treatment for children with CP because that subjects needs an exercise therapy. Randomized sampling of each stratum was used to divide the participants into 2 groups of seven children: the WBVAO group and the WBV group. The WBVAO group completed WBV training along with action observation for 30 min a day, 3 days a week for a 4-week period, and the WBV group completed only the WBV training for 30 min a day, 3 days a week for a 4-week period. The experimental and control groups also performed 30 min a day of conservative physical therapy, 3 days a week for a 4-week period.
WBV training along with action observation was performed to increase gross motor function, balance, and walking ability. The children assigned to the WBVAO group were instructed to maintain a standing posture on a vibration pad, supported and prevent falls by a back plate at the pelvis and spine. Children stood barefoot with feet parallel and knees in slight flexion (30°). The participants were instructed to watch a video on a 17-inch laptop screen from a distance of 50 cm during this time and were either instructed to follow or to not follow the actions demonstrated in the video. The model for the video comprised of actions performed by an average adult of normal body weight. It included six actions to improve lower extremity strength, balance, and gait (
The first action was a standing position with feet parallel and the knees in slight flexion (30°). The second action comprised a sitting and standing movement over a limited range of motion, and the third action comprised a rotating movement from a standing position, training the ability to shift body weight from side to side. The fourth action involved shifting body weight forward and backward while standing in a split stance with the right foot forward, and the fifth action was similar as the fourth action except with the left foot forward. The sixth action was similar to the first one, with participants required to maintain a standing position with the knees in slight flexion (30°). Exercises for each of the six actions were performed after a minute of watching the video. Three minutes of physical training was completed for each action, followed by 1 min of rest. The total physical therapy time was therefore 30 min. The intensity of the WBV stimulation to improve muscle strength was 12–18 Hz, and it was applied by gradually increasing the intensity by 0.5 Hz starting with the intensity the each participant could withstand. The reason why the same intensity was not applied to all participants was because the age, disability, function, and sensory differences of CP were considered (
The WBV group stood on the vibration pad in the same position and training protocols as the WBVAO group without action observation. During the 30 min of therapy, every 3 min of vibration training and 2 min of rest were repeated 6 times. The intensity of the WBV stimulation for muscular strength improvement was similar as the WBVAO group (12–18 Hz) and was applied by gradually increasing the intensity by 0.5 Hz starting from the intensity the participant could withstand.
The 5 times sit to stand (FTSTS) test was used to examine functional muscular strength of the lower extremity. The FTSTS test was initiated from a sitting position on a knee high bench with the hip joint in 90° flexion and the feet touching the floor. In this position, the lateral ankle bone was located 10 cm posterior to a perpendicular line drawn from the center of the knee. The time taken to perform the FTSTS test with the arms crossed and without any help from the upper extremity was recorded (
The GMFM was used to assess gross motor function. The GMFM is divided into the following five domains: A (lying and rolling, 17 items), B (sitting, 20 items), C (quadruped and kneeling, 14 items), D (standing, 13 items), and E (walking, running, and jumping, 24 items) (
Balance function was evaluated using the Pediatric Balance Scale (PBS), Timed Up and Go (TUG) test, and pediatric reach test (PRT). The PBS comprises 14 tasks similar to activities of daily living. The items are scored on a 5-point scale, with zero denoting an inability to perform the activity without assistance and four denoting the ability to perform the task with complete independence. The maximum score is 56 points. The interrater reliability (ICC value) for the PBS test was 0.99, with an ICC value of 0.99 for the test-retest reliability (
Gait function was examined using the 10-m walk test (10MWT), 6-min walk test (6MWT), and timed up and down stair (TUDS) test. Gait velocity was measured using the 10MWT. Participants completed three trials in succession, with a brief seated or standing rest as needed between trials. An ICC of 0.81 for the 10MWT has been reported across participants (
All statistical analyses were performed using the IBM SPSS Statistics ver. 20.0 (IBM Co., Armonk, NY, USA). Descriptive statistics for the baseline variables were calculated to characterize and compare the two study groups. The Shapiro–Wilk test was used to determine whether the general characteristics and the outcome measures of the participants were normally distributed. Means and standard deviations are reported for the normally distributed variables. Independent
The characteristics of the 14 participants who completed the experiment are shown in
Differences in lower extremity functional strength after the intervention are shown in
A comparison of GMFM within and between groups is shown in
Comparisons of the balance functions within and between groups are shown in
Comparisons of the gait functions within and between groups are shown in
In a child with CP, muscle weakness is one of the factors that decreases motor functions, and these decreases in motor function even affect the control of body functions (
Balance comprises stability in both static (including standing or sitting) and dynamic (including reaching with the hands or walking) postures. According to these definitions, children with CP lack the voluntary postural stability required for daily activities. The body’s reactive balance ability in response to external change is also affected due to severe loss of muscular strength, abnormal muscle tension, and a lack of motor control (
A child with CP presents with symptoms including muscular strength weakness due to a damaged central nervous system, abnormal muscle tone including spasticity, a decrease in sensory function, a loss of the abilities to regulate muscle, and decreased balance ability due to an unstable posture. As a result, these children experience difficulties in achieving independent walking and activities of daily life (
In this study, the WBVAO group showed a significant improvement in 10MWT score with the time taken to complete the test decreasing from 13.60 sec in the pretest to 13.10 sec in the posttest (
This study has the following limitations: this study has a short 4-week intervention period; the frequency of application in WBV is limited in this study; prior studies, which may serve as reference studies, are not available; and this study comprises a small sample size. This makes it difficult to generalize the findings to all children with CP. It is also difficult to control all the factors that might affect the child’s activities of daily living. Furthermore, several of the participants had a short attention span while concentrating on the action observation, making it difficult for the treatment to last long as planned. Some of the CP in the WBVAO group did not follow the actions demonstrated in the video because of severity. This could be explained by the fact that children with spastic CP are not only impaired by the regulation ability of the muscular system and sensory deprivation but are also deprive of cognitive function (
This study was supported by a grant from the NRF (NRF-2018R1D1A1B07045746), which is funded by the Korean government.
No potential conflict of interest relevant to this article was reported.
General characteristics of the participants (n=14)
Parameter | WBVAO group (n=7) | WBV group (n=7) | ||
---|---|---|---|---|
Age (yr) | 9.00±3.26 | 8.71±3.19 | 0.165 | 0.871 |
| ||||
Height (cm) | 130.71±20.92 | 131.57±22.09 | −0.075 | 0.942 |
| ||||
Weight (kg) | 32.42±10.96 | 30.85±12.45 | 0.251 | 0.806 |
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Sex | ||||
Male | 3 (43.0) | 3 (43.0) | 0.000 | 1.000 |
Female | 4 (57.0) | 4 (57.0) | ||
| ||||
GMFCS (level) | 1.57 (0.78) | 1.71 (0.75) | −0.346 | 0.735 |
1:2:3 | 4:2:1 | 3:3:1 |
Values are presented as mean±standard deviation or number (%).
WBVAO, whole-body vibration combined with action observation; WBV, whole-body vibration; GMFCS, Gross Motor Function Classification System Scale.
Comparison of lower extremity functional strength within and between groups (n=14)
FTSTS (sec) | WBVAO group (n=7) | WBV group (n=7) | ||
---|---|---|---|---|
Before | 15.31±5.95 | 17.12±6.88 | −0.527 | 0.608 |
After | 14.51±6.10 | 16.88±7.00 | −0.617 | 0.549 |
After–before | −0.80±0.36 | −0.44±0.15 | −2.365 | 0.046 |
−5.748 | −7.803 | |||
0.001 | 0.000 |
Values are presented as mean±standard deviation.
FTSTS, 5 times sit to stand test; WBVAO, whole-body vibration combined with action observation; WBV, whole-body vibration.
Comparison of gross motor function within and between groups (n=14)
Parameter | WBVAO group (n=7) | WBV group (n=7) | ||
---|---|---|---|---|
GMFM-D (%) | ||||
Before | 79.53±11.26 | 77.65±13.46 | 0.284 | 0.781 |
After | 83.78±11.24 | 80.21±13.94 | 0.541 | 0.599 |
After–before | 4.34±1.34 | 2.56±1.48 | 2.351 | 0.037 |
|
8.537 | 4.586 | ||
|
0.000 | 0.004 | ||
| ||||
GMFM-E (%) | ||||
Before | 68.64±18.31 | 63.87±19.81 | 0.468 | 0.648 |
After | 71.22±17.99 | 66.05±20.13 | 0.507 | 0.621 |
After–before | 2.57±1.24 | 2.17±1.07 | 0.647 | 0.530 |
|
5.474 | 5.349 | ||
|
0.002 | 0.002 |
Values are presented as mean±standard deviation.
WBVAO, whole-body vibration combined with action observation; WBV, whole-body vibration; GMFM, Gross Motor Function Measure.
Comparison of balance within and between groups (n=14)
Parameter | WBVAO group (n=7) | WBV group (n=7) | ||
---|---|---|---|---|
PBS (score) | ||||
Before | 43.71±8.75 | 40.42±9.62 | 0.668 | 0.517 |
After | 45.71±9.12 | 41.71±9.97 | 0.783 | 0.449 |
After–before | 2.00±0.57 | 1.28±0.48 | 2.500 | 0.028 |
|
9.165 | 6.971 | ||
|
0.000 | 0.000 | ||
| ||||
TUG (sec) | ||||
Before | 12.86±6.97 | 14.67±7.80 | −0.458 | 0.655 |
After | 12.21±7.08 | 14.33±7.72 | −0.536 | 0.602 |
After–before | −0.65±0.32 | −0.34±0.22 | −2.065 | 0.061 |
|
−5.237 | −3.990 | ||
|
0.002 | 0.007 | ||
| ||||
PRT (cm) | ||||
Before | 12.28±3.09 | 11.21±3.60 | 0.597 | 0.562 |
After | 13.00±3.51 | 11.64±3.68 | 0.706 | 0.494 |
After–before | 0.71±0.75 | 0.42±0.53 | 0.816 | 0.430 |
|
2.500 | 2.121 | ||
|
0.047 | 0.078 |
Values are presented as mean±standard deviation.
WBVAO, whole-body vibration combined with action observation; WBV, whole-body vibration; PBS, Pediatric Balance Scale; TUG, Timed Up and Go test; PRT, pediatric reach test.
Comparison of gait within and between groups (n=14)
Parameter | WBVAO group (n=7) | WBV group (n=7) | ||
---|---|---|---|---|
10MWT (sec) | ||||
Before | 13.60±7.10 | 13.71±8.49 | −0.027 | 0.979 |
After | 13.10±7.17 | 13.47±8.34 | −0.090 | 0.930 |
After–before | −0.50±0.28 | −0.24±0.41 | −1.370 | 0.196 |
|
−4.689 | −1.563 | ||
|
0.003 | 0.169 | ||
| ||||
6MWT (m) | ||||
Before | 284.28±95.76 | 269.28±104.42 | 0.280 | 0.784 |
After | 300.71±97.44 | 280.00±106.41 | 0.366 | 0.721 |
After–before | 16.42±3.77 | 10.71±4.49 | 2.573 | 0.024 |
|
11.500 | 6.301 | ||
|
0.000 | 0.001 | ||
| ||||
TUDS (sec) | ||||
Before | 22.95±11.11 | 25.35±12.77 | −0.375 | 0.714 |
After | 21.98±11.34 | 24.78±12.90 | −0.431 | 0.674 |
After–before | −0.97±0.27 | −0.56±0.22 | −2.958 | 0.012 |
|
−9.231 | −6.577 | ||
|
0.000 | 0.001 |
Values are presented as mean±standard deviation.
WBVAO, whole-body vibration combined with action observation; WBV, whole-body vibration; 10MWT, 10-m walk test; 6MWT, 6-min walk test; TUDS, timed up and down stair test.