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Table of Contents
ORIGINAL ARTICLE
Year : 2018  |  Volume : 50  |  Issue : 3  |  Page : 76-80

Effect of reactive postural adjustment and anticipatory postural adjustment in improving sitting balance in children with spastic diplegic cerebral palsy


1 Department of Orthopedics, Occupational Therapy Unit, Sir Sunderlal Hospital, Banaras Hindu University, Varanasi, Uttar Pradesh, India
2 Department of Occupational Therapy, Swami Vivekananda National Institute of Rehabilitation Training and Research, Cuttack, Odisha, India
3 Department of Rehabilitation, Kiran Society Madhopur, Varanasi, Uttar Pradesh, India

Date of Web Publication9-Nov-2018

Correspondence Address:
Dr. Jaya Dixit
Room No 108, Rehabilitation Unit, Sir Sunderlal Hospitals, Banaras Hindu University, Varanasi, Uttar Pradesh
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0445-7706.244552

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  Abstract 


Background: The purpose of this study was to examine the effect of providing activities which give internal and external perturbations on the static and dynamic trunk balancing abilities of children with cerebral palsy and generate some postural response in the trunk of these children with cerebral palsy. Objectives: To find out the effect of activities providing reactive postural adjustments and anticipatory postural adjustments, in improving sitting balance, in children with spastic diplegic cerebral palsy. Study Design: Pre- and posttest study design. Methods: Children with spastic diplegic cerebral palsy who were fulfilling the inclusion criteria were selected by convenient sampling from the department of occupational therapy, with a sample size of 60. Written informed consent was obtained from the guardians. Ethical permission was taken from the institute. Pediatric balance scale and pediatric reach test were used as instruments for measuring improvement in sitting balance. A frame for reaching and a platform for external perturbation were designed for the study. Therapy for both groups was given for 1 h/session. Children in the experimental group were exposed to 15 min each of reactive postural adjustment and anticipatory postural adjustment along with 1 h of conventional occupational therapy, whereas children in the control group were exposed to 1 h of conventional occupational therapy. Results: The results of the Wilcoxon signed-rank test of pediatric reach test were significant for experimental and control groups (P = 0.004; 95% confidence interval [CI]: 5.34–10.67 and P = 0.014; 95% CI: 4.16–7.89, respectively). There was also significance of the results of the Wilcoxon signed-rank test of pediatric balance scale in the experimental and control groups (P = 0.025; 95% CI: 8.98–11.12 for experimental group and P = 0.005; 95% CI: 8.09–9.54 for control group), with the level of significance set at P ≤ 0.05. This shows that the results were significant for experimental group as well as control group. Furthermore, the results of the Mann–Whitney U-test showed that Z = −3.507 for pediatric balance scale is more, making it more sensitive to capture changes in balances in children than that for pediatric reach test with Z = −3.905 (P = 0.002; 95% CI: 4.14–9.00 for pediatric balance scale and P = 0.001; 95% CI: 7.56–9.70 for pediatric reach test), with the level of significance set at P ≤ 0.05. Conclusion: It can be concluded that activities providing reactive postural adjustment and anticipatory postural adjustment can be used to enhance and improve sitting balance among children with spastic diplegic cerebral palsy, so that they can have the functional balance in sitting, to safely meet the demands of everyday life.

Keywords: Balance, Functional Activities, Perturbations


How to cite this article:
Dixit J, Senapati A, Kumar A. Effect of reactive postural adjustment and anticipatory postural adjustment in improving sitting balance in children with spastic diplegic cerebral palsy. Indian J Occup Ther 2018;50:76-80

How to cite this URL:
Dixit J, Senapati A, Kumar A. Effect of reactive postural adjustment and anticipatory postural adjustment in improving sitting balance in children with spastic diplegic cerebral palsy. Indian J Occup Ther [serial online] 2018 [cited 2020 Oct 29];50:76-80. Available from: http://www.ijotonweb.org/text.asp?2018/50/3/76/244552




  Introduction Top


Cerebral palsy is an umbrella term covering a group of nonprogressive, but often changing, motor impairment syndromes secondary to lesion or anomalies of the immature brain. Decreased sitting balance in children with cerebral palsy leads to abnormal compensatory pattern of trunk and affects upper extremity performance. This hampers their independence in functional activities and activities of daily living which need independent functioning of upper extremity.[1] Reaching for an object in sitting position requires the ability to balance and move the body mass over the base of the support. Reaching at various directions and distances tends to challenge an individual's limit of stability which was found to be reduced in children with cerebral palsy.[2] The control mechanism for reacting to unexpected external postural perturbation is reactive postural adjustment[3] and that for anticipating internal postural perturbation related to the production of voluntary movement is anticipatory postural adjustment.[4] Children with cerebral palsy were examined in response to anticipatory postural perturbations by pulling a movable lever in standing; electromyography was recorded from lower extremity, trunk, and arm musculature. Children with cerebral palsy demonstrated a proximal-to-distal pattern as opposed to distal-to-proximal pattern demonstrated by normal children. Children with cerebral palsy failed to demonstrate anticipatory activation of postural muscles which shows that anticipatory postural adjustment in children with spastic diplegic cerebral palsy is severely impaired.[5] Reactive postural adjustment is impaired among children with spastic diplegic cerebral palsy in different positions including sitting. The results of sitting perturbation studies suggested that children with cerebral palsy have disordered muscle activations which are reactive postural adjustment reversals (reversals of cephalocaudal muscle activation, simultaneous activation of ventral muscles, and excessive co-contractions) for sitting postural control.[6] Both reactive postural adjustment and anticipatory postural adjustment have been studied and followed; however, there is a paucity of studies showing its effect on improving sitting balance in children with spastic diplegic cerebral palsy.


  Methods Top


The study was conducted between January 2008 and January 2009 at the Department of Occupational Therapy, Swami Vivekananda National Institute of Rehabilitation Training and Research (SVNIRTAR), Cuttack. Sixty children who were diagnosed as spastic diplegic cerebral palsy and referred to the Department of Occupational Therapy by the Department of Physical Medicine and Rehabilitation of SVNIRTAR, Cuttack, were selected by convenient sampling. This was a pretest and posttest experimental study.

Inclusion Criteria

  1. Children with spastic diplegic cerebral palsy
  2. Children between the age group of 3 to 8 years
  3. Children in level 3 and 4 of Chailey floor sitting assessment
  4. Children having Grade 1 criteria of the modified Ashworth scale.


Exclusion Criteria

  1. Children having other types of cerebral palsy
  2. Those children who had cognitive problems making it difficult to follow the instructions
  3. Children having associated neurological problems
  4. Children having severe-to-moderate mental retardation.


Variables of the Study

Activities providing reactive postural adjustments and anticipatory postural adjustments were provided to the children as independent variables, and sitting balance was considered as dependent.

Instruments Used

Pediatric balance scale and pediatric reach test were used as instruments, to measure the changes in sitting balance in these children.

A frame was made with plastic to encourage horizontal and to cross midline functional reach. This frame has two vertical plastic tubes placed over the wooden base and small platform made of ether flex secured in three positions. The width of the wooden base was 45 cm and the height of the two vertical plastic pipes was 46 cm. Three platforms were positioned on the frame, and each consecutive platform was 10 cm above the previous platform located on the far right and the far left of the frame. Two vertical plastic pipes along with small platforms were connected to the wooden base, which allowed the frame to slide forward and away from the child to accommodate each child's arm length. We considered the reach to be successful when the child touched (i.e., not grasped) the stickers which were placed over the platforms in the frame. To assure consistency, the motivation was chosen according to the child's preferences.[5]

A platform for providing external perturbation was made with a wood of 48 cm × 37 cm with 10 cm height from the floor. It had four small wheels in the inferior surface, which made it move in forward and backward directions. The speed of the movement was 60 mm at 100–350 mm/s.[6]

Procedures

The parents of the selected children were explained about the activities providing reactive postural adjustments and anticipatory postural adjustments to their children and were told about the outcome of the study. Written informed consent was taken from the guardians of the children with cerebral palsy who were taking part in the study. Ethical permission was also obtained from the institute for conducting the study.

The children who were fulfilling the inclusion criteria were randomly distributed into two equal groups: experimental group, and control group. A baseline assessment score of sitting balance was collected by performing pediatric balance scale and pediatric reach test for children present in both the groups. Therapy for both the groups consisted of 1 h of session. Children in the experimental group were provided 15 min each of anticipatory postural adjustment and reactive postural adjustment along with conventional occupational therapy. Children in the control group were given conventional occupational therapy alone. Posttest scores of pediatric balance scale and pediatric reach test were recorded after 9 months of the study.

Protocol

Conventional occupational therapy included activities based on the neurodevelopmental therapy which included positioning in a relaxation chair with toys on lap board and balancing activities such as ball throwing and catching, balance board, and swinging activities. Strengthening of trunk muscles and lower limb muscles was also included based on the biomechanical approach. In the experimental group, anticipatory postural adjustment activity was provided to the children by placing them in a comfortable and secured sitting over the mat. They were encouraged to touch cartoon stickers placed over the platform in the frame placed in front of them [Figure 1]. For providing activity of reactive postural adjustment, children were placed comfortably and securely over the movable platform and were given forward/backward perturbations, which caused body to sway, forward and backward. Two mats were placed on either side of the platform to avoid injury to the children [Figure 2]. All the activities given were demonstrated initially.
Figure 1: A child performing an activity providing anticipatory postural adjustment on frame

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Figure 2: A child performing an activity providing reactive postural adjustment over the platform

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  Results Top


Data Analysis

The test parameters were compared before and after therapy. Statistical calculations were performed with IBM SPSS Statistics for windows, version 16.0 (IBM Corp., Armonk, NY: USA). Statistical test was carried with the level of significance set at P ≤ 0.05. The raw scores of pediatric balance scale and pediatric reach test pre- and postintervention were added and summed up into final scores. It was two-tailed nonparametric study because of ordinal data and small sample size. The changes in the pediatric balance scale and pediatric reach test within experimental and control groups were analyzed using the Wilcoxon signed-rank test. The Mann–Whitney U-test was performed for knowing the significance outside the group.

Descriptive Characteristics

A number of patients in the experimental and control groups were thirty in each within the age range of 3–7 years in the experimental group and 3–8 years in the control group. The mean age was 5.20 ± 1.31 in the experimental group and 6.00 ± 1.63 in the control group. There were 15 males and 15 females in the experimental group whereas 13 males and 17 females were in the control group [Table 1]. The Wilcoxon signed-rank test for pediatric reach test showed significant results in the experimental and control groups (P = 0.004; 95% confidence interval [CI]: 5.34–10.67 and P = 0.014; 95% CI: 4.16–7.89 [Z = −2.877 and Z = 2.449], respectively), with the level of significance set at P ≤ 0.05 [Table 2].
Table 1: Descriptive characteristics

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Table 2: Results of Wilcoxon signed rank test (pediatric reach test)

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The Wilcoxon signed-rank test for pediatric balance scale showed that the findings were more significant for experimental group as compared to control group (P = 0.025; 95% CI: 8.98–11.12 for experimental group and P = 0.005; 95% CI: 8.09–9.54 for control group [Z = −2.236 and Z = −2.810], respectively), with the level of significance set at P ≤ 0.05 [Table 3].
Table 3: Results of Wilcoxon signed-rank test (pediatric balance scale)

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The results of the Mann–Whitney U-test showed Z = −3.507 for pediatric balance scale, making it more sensitive to capture changes in balances in children as compared to pediatric reach test with Z = −3.905 (P = 0.002; 95% CI: 4.14–9.00 and P = 0.001; 95% CI: 7.56–9.70, respectively), with the level of significance set at P ≤ 0.05 [Table 4].
Table 4: Results of Mann-Whitney U-test (pediatric balance scale and pediatric reach test)

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  Discussion Top


Sitting balance is commonly affected in children with cerebral palsy, leading to difficulty in functional performance of upper extremity, as these children frequently use upper extremity for maintaining balance in sitting. Hence, sitting is an important area for intervention to be considered in occupational therapy while treating children with spastic diplegic cerebral palsy. The purpose of this study was to determine whether children with spastic diplegic cerebral palsy, who were given activities providing reactive postural adjustment and anticipatory postural adjustment in addition to conventional therapy, would exhibit greater improvement in sitting balance than those who merely received the conventional occupational therapy. The results of this study indicate that, if we provide perturbations to children with spastic diplegic cerebral palsy the postural adjustments in trunk, neck and lower extremity, helps them to have functional balance in sitting. These results can be supported by the results of the study by Shumway-Cook et al., who found that typically developing children showed improvement in sitting balance in response to the massed practice on a moveable platform providing external perturbations.[6] Furthermore, the results can be supported by the study by Kaminski and Simpkins; their study results suggested that, during the performance of a functional task, dynamic changes that occur in the trunk and lower extremities before initiation of arm movement serve to stabilize the body and are used to initiate and assist whole body reaching.[7] Applying a general system theory of motor control, within both reactive postural adjustment and anticipatory postural adjustment, there are several systems that coordinate to produce and affect the balance of an individual both in stance and in sitting.[8] At least three systems of sensory, motor, and musculoskeletal participate in maintaining the balance. The sensory system cues the individual that there has been a perturbation which is provided by tactile, verbal, and visual systems, in this study about perturbation, and/or gives feedback for adjustment during movement and after movement, in regard to how successful the postural activity generated has been. In this study, all types of sensory cues required for balance in sitting were provided during the intervention. Sensory cues included tactile cues such as touching sticker, verbal cues such as encouraging verbally for touching the sticker, and visual cues such as asking them to look at reaching the frame and go for sticker at different levels on the frame during the activity, providing anticipatory postural adjustment. And, during reactive postural adjustment, sensory feedback was provided by verbal commands such as “try to balance yourself when I am moving you forward and backward.” Visual cues are provided by telling them “see you moved this distance when I moved you forward and backward.” Motor system organizes and cues appropriate activation of the muscle, while musculoskeletal system provides framework on which we move and create the force to produce the postural activity.[4] During the activities providing reactive postural adjustments, children were given forward platform movements, which causes the body to sway backward, with eliciting responses in the neck, trunk, and lower limb muscle mostly in the flexor group.[15] And, they were also given backward platform perturbations, causing forward sway, and variable responses were elicited in the trunk and neck extensors.[9] While performing activities providing anticipatory postural adjustments, children are trying to use neck flexors, trunk flexors, and shoulder flexors for reaching forward and neck extensors, trunk extensors, and shoulder extensors for coming back to initial position after reaching, which facilitates balance in sitting position. The state of any of these systems affects the overall postural activity in the individual. Other systems can also have an effect on the postural activity, like the directions given to the individuals, or the behavioral state and alertness of the individual.[10] These components of balance were also taken care of while providing the activities. The improvement in balance as measured by pediatric balance scale and pediatric reach test can be attributed to an improvement in the coordination and recruitment of trunk and limb musculature that occurs as a result of practicing anticipatory postural adjustment and reactive postural adjustment through different types of activities.[11] It has been shown that the self-initiated perturbation to the system as implemented during the reaching protocol is superior to other forms of training as they challenge the limits of stability. It is important, however, that practice should be organized such that children are made to reach the objects placed beyond the arm's length. This is important because reaching beyond the arm's length causes a destabilizing effect on the body and generates anticipatory muscle response in the trunk and lower limb for restoration of balance, unlike reaching within the arm's length which mostly involves upper limb musculature.[7] Repetition of the task is a prerequisite to skill acquisition, including balance in sitting; repetition in this study is provided by giving the same activities throughout the study in each session.[12] Motor and cognitive processes are employed to acquire the skill and maintain balance when subjected to external perturbations. Activities providing anticipatory postural adjustment and reactive postural adjustment which are used in this study need both cognition and motor process for performance. With every repetition, cognitive processes are used to evaluate feedback from the previous action and new action plan is formed for a forthcoming movements. Less improvement in pre- and posttest score of pediatric balance scale[13] and pediatric reach test[14] in the control group may be attributed to not providing appropriate perturbations (both internal perturbation and external perturbation) to the children generating necessary postural response, needed for balancing in sitting posture.

Limitations

  1. Duration of the study was small
  2. Small sample size
  3. Overhead reaching activities were not taken for activities providing anticipatory postural adjustment
  4. No follow-up study was done.


Recommendations

  1. Studies could be made by providing functional activities which provide balance perturbations for improving sitting balance
  2. Additional studies can be conducted of long-term benefits on children with cerebral palsy and other functional disabilities
  3. Future efforts also need to examine the effectiveness of balance perturbations with a large sample
  4. Future studies in which improvement in sitting balance is captured by different measures should include a functional measure.



  Conclusion Top


The results of this study indicate that there is a significant effect of activities providing reactive postural adjustment and anticipatory postural adjustment on sitting balance. It can be concluded that activities providing reactive postural adjustment and anticipatory postural adjustment can enhance and improve sitting balance among children with spastic diplegic cerebral palsy, so that they can have the functional balance in sitting, to safely meet demands of everyday life.

Acknowledgment

Sincere thanks to Mr. S. P. Mokashi, Associate Professor and Head of the Department of Occupational Therapy, SVNIRTAR, for his continuous encouragement and support. I acknowledge the Director, Dr. Sanjay Das, SVNIRTAR, for allowing me to do my dissertation work with the patients of SVNIRTAR. Thanks to my family members, friends, and well-wishers for having faith on me that I can do this work. Finally, I thank my patients and their parents for trusting me and their cooperation during the course of study. Above all, I thank God Almighty for providing me all that I wanted and much more to carry out my study.

Declaration of Patient Consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the parent(s) has/have given his/her/their consent for his/her/their child images and other clinical information to be reported in the journal. The parent understand that their child names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

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Levitt S. Treatment of Cerebral Palsy and Motor Delayed. 4th ed. Wiley- Blackwell: Blackwell Publication, Oxford University Press; 2004. p. 23-32.  Back to cited text no. 1
    
2.
Lowes LP, Westcott SL, Palisano RJ, Effgen SK, Orlin MN. Muscle force and range of motion as predictors of standing balance in children with cerebral palsy. Phys Occup Ther Pediatr 2004;24:57-77.  Back to cited text no. 2
    
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Keshner EA, Woollacott MH, Debu B. Neck, trunk and limb muscle responses during postural perturbations in humans. Exp Brain Res 1988;71:455-466.  Back to cited text no. 3
    
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Westcott SL, Burtner PA. Postural control in children: Implications for pediatric practice. Phys Occup Ther Pediatr 2004;24:5-5.  Back to cited text no. 4
    
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Gayle A, Wiens PT, Pitetti KP. A method for measure reaching capacity of children with neuromuscular disorders. Pediatr Phys Ther 2006;18:226-228.  Back to cited text no. 5
    
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Shumway-Cook A, Hutchinson S, Kartin D, Price R, Woollacott M. Effect of balance training on recovery of stability in children with cerebral palsy. Dev Med Child Neurol 2003;45:591-602.  Back to cited text no. 6
    
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Kaminski TR, Simpkins S. The effects of stance configuration and target distance on reaching. I. Movement preparation. Exp Brain Res 2001;136:439-446.  Back to cited text no. 7
    
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Bernstein N. Coordination and Regulation of Movement. 2nd ed. Pergamon-Press, UK, oxford university press: Dergranmon Publications, Oxford University Press; 1967.  Back to cited text no. 8
    
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Shumway Cook A, Woollcott MH. Motor Control Theory and Practical Applications. 2nd ed. Lippincott Williams and Wilkins: Oxford University Press; 2001.  Back to cited text no. 9
    
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Cordo PJ, Nashner LM. Properties of postural adjustments associated with rapid arm movements. J Neurophysiol 1982;47:287-302.  Back to cited text no. 10
    
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Dean CM, Shepherd RB. Task-related training improves performance of seated reaching tasks after stroke. A randomized controlled trial. Stroke 1997;28:722-728.  Back to cited text no. 11
    
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Schmidt RA, Wrisberg CA. Motor Learning and Performance: A Situation Based Learning Approach. Champaign, IL, US: Human Kinetics; 2008.  Back to cited text no. 12
    
13.
Franjoine MR, Gunther JS, Taylor MJ. Pediatric balance scale: A modified version of the berg balance scale for the school-age child with mild to moderate motor impairment. Pediatr Phys Ther 2003;15:114-128.  Back to cited text no. 13
    
14.
Bartlett D, Birmingham T. Validity and reliability of a pediatric reach test. Pediatr Phys Ther 2003;15:84-92.  Back to cited text no. 14
    
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Forssberg H, Hirschfeld H. Postural adjustments in sitting humans following external perturbations: Muscle activity and kinematics. Exp Brain Res 1994;97:515-527.  Back to cited text no. 15
    


    Figures

  [Figure 1], [Figure 2]
 
 
    Tables

  [Table 1], [Table 2], [Table 3], [Table 4]



 

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