This study was designed as a cross-sectional study and ethical approval was obtained from the Hacettepe University ethical committee (Decision no: HEK11/105) according to principles of the Declaration of Helsinki, and the parents of participant children gave written informed consent to participate.
Participants
Children with spastic CP aged 6–16 years were included in the study. Study size was identified as 20 children with CP after power analysis, 31 children included at the beginning, 4 of the children did not complete posturographic evaluation because of difficulty, 2 of them had been applied Botulinum-toxin injection and excluded from study. Finally, 25 children with spastic CP were completed the study. Inclusion criteria were: diagnosis of spastic CP, able to walk independently without any orthotics; not having cognitive impairment; not having vision problems and hearing loss. Children who underwent Botulinum toxin injections and/or surgical intervention for the musculoskeletal system in the past year, who were using any medication were excluded from study. None of participant was undergone to the posturographic study before. Demographic characteristics of children, including gender, height, weight was recorded. Children classified according to the Gross Motor Function Classification System (GMFCS). The characteristics of children with CP presented in Table 1.
Table 1
Characteristics of children with CP
Characteristics (n = 25)
|
Age (year) Mean ± SD
|
9.64 ± 4.73
|
Gender
|
Girl (n)
|
13 (52%)
|
Boy (n)
|
12 (48%)
|
GMFCS
|
Level I
|
13 (52%)
|
Level II
|
12 (48%)
|
Height (cm) Mean ± SD
|
128.16 ± 23.64
|
Weight (kg) X ± SD
|
31.12 ± 15.93
|
GMFCS: Gross Motor Function Classification System n: number, SD: standard deviation, |
Posturographic Evaluation
Postural stability of participants was measured by Computerized Dynamic Posturography (CDP) (NeuroCom International, Inc., Clackamas, OR, USA), Smart Balance Master which has visual biofeedback on either a stable or unstable support surface and visual environment is used for assessment. With this technique, individual’s ability of use visual, vestibular, and somatosensory information can be evaluated. Smart Balance Master assesses a dynamic force plate with rotation capabilities to quantify the vertical forces exerted through the patient’s feet to measure center of gravity (COG) position and PC; and a dynamic visual surround to measure the patient’s use of visual information to maintain balance [13].
The Sensory Organization Test (SOT) protocol assesses postural balance abilities under six conditions in which visual, sensory, and proprioceptive inputs vary. During the SOT, information delivered to the patient’s eyes, feet and joints is effectively eliminated through calibrated ‘‘sway referencing’’ of the support surface and/or visual surround, which tilt to directly follow the patient’s antero-posterior body sway. An equilibrium-score determines the amount of the anteroposterior COG compared with maximal sway limits was calculated for each condition. A composite balance score (CBS) is subsequently calculated. The scores range from 0-100, higher values indicating better stability. The six different conditions were: SOT-1, stable surface, eyes open; SOT-2, stable surface, eyes closed; SOT-3, eyes open with sway referenced surrounded; SOT-4, eyes open with sway referenced surface; SOT-5, eyes closed with sway referenced surface; and SOT-6, eyes open, referenced surface and surround. SOT-1, SOT2, and SOT-3 are static conditions, while SOT-4, SOT-5, and SOT-6 are dynamic conditions. SOT-1-2 refer to patient’s ability to utilize input from the somatosensory system and maintain balance. SOT-1-4 give objective information about patient’s ability of the visual system to maintain balance. SOT-1-5 are identifying ability of using input from vestibular system. Two postural adjustment strategies were examined: relative movements of ankle (ankle strategy) or hip (hip strategy). A software program calculates an equilibrium score, which determines the success of the patient’s sway for each sensory condition. Each test condition was repeated three times, and the average of the three trials was used for data analysis [13].
Trunk Impairment Scale (Tis)
The trunk control of participants was evaluated using the TIS. The validity and reliability of TIS for patients with CP has been demonstrated. The TIS consists of three sub-sections: static balance, dynamic balance, and coordination. Task scores for each activity range from 0–2. The total score ranges from 0–23. Higher total scores indicate better trunk control in sitting posture [14].
Functional Mobility Assessment
The modified Timed Up and Go (mTUG) and Gross Motor Function Measure (GMFM) were used to assess functional mobility. The pediatric version of the mTUG was performed for functional mobility assessment. It records the time a child needs to stand up from a chair with foot contact, to walk three meter to a target, turn around and return to the chair and sit down. We performed three mTUG trials and calculated the mean time. Reliability and validity of the mTUG were shown [15].
The GMFM-88 is the most commonly used, valid and reliable measure to evaluate motor function in children with CP, that contains five sections and 88 items. The total score of the GMFM-88 is obtained by adding up the total points for each section. A total score or the scores of each section can be used separately. In this study, we used Section-E to measure walking function [16].
Lower Limb Impairment Assessment
Spasticity and limitations of ROM assessment of lower limb assessed. The measurements were made without clothing.
Modified Ashworth Scale (MAS) was used to evaluate spasticity of the gastrocnemius, soleus, hamstring, hip adductor and flexors muscles were evaluated bilaterally. The MAS is a commonly used scale for measuring muscle tone during passive movement with a 6-point scale: (0–4) The MAS is valid and reliable in children with CP [17, 18].
For ROM assessment, a universal goniometry which is valid and reliable in children with CP [19], was used in the evaluation of ROM and Kendall’s values were taken as reference and limitation values were recorded. The ankle dorsiflexion, plantar flexion, eversion and inversion; knee flexion and extension; hip flexion, extension, abduction, adduction, internal and external rotation movements were evaluated passively in the lower extremity.
Statistical Analysis:
Data analysis was completed using the statistical software program SPSS for Windows v.21.0 (SPSS Inc., Chicago, IL). The Shapiro-Wilk’s test was used to test normality. Data were expressed as means standard deviations. The analysis of the linear relationship was performed Spearman's correlation analysis. The statistical significance level was accepted as p < 0.05. Simple and multiple linear regression analysis (backward modeling) were carried out to determine the most important predictor(s) for explaining mTUG and GMFM-E variance.