Factors of Influence on the Walking Ability of Children with Spastic Cerebral Palsy J. Phys. Ther. Sci. 10: 1 5, 1998 ATSUSHI FURUKAWA, RPT 1), EIJI NII, MD, PhD 1), HIROYASU IWATSUKI, RPT 2), MASAKI NISHIYAMA, MD 1), ATSUMASA UCHIDA, MD, PhD 3) 1) Department of Physical Therapy, Kusanomi Rehabilitation Center for Children, 29 25 Shiroyama-ichiioume, Tsu City, Mie 514-0818, Japan. TEL +81 59-234-2178 2) Department of Rehabilitation Medicine, Inazawa City Hospital 3) Department of Orthopaedic Surgery, Mie University School of Medicine Abstract. Children with spastic cerebral palsy (CP) have a strictly individual gait with numerous variations, which is also characterized by increased tonus and hyperreflexion of the muscles. These factors lead to a gait pattern that is inefficient in terms of consumption of energy. The purpose of this study was to clarify the major factor of the deterioration of walking ability on patients with cerebral palsy. Eighteen children (ten boys, eight girls, average age 12.7 years) with CP participated in the study. The children were divided into groups: the independent walking group and the walking aid group (walking with crutches and wheeled walkers); and the diplegia group and the hemiplegia group. The physiological cost index (PCI) for a 3 minute walk at comfortable speed was measured. PCI was compared to the reaction of the cardio-pulmonary system in basic motions (standing up from a table and 10 m walking). Through this test, the whole heart rate and 10 m walking time were measured. PCI and 10 m walking time in the independent walking group and the hemiplegia group were significantly lower than in the walking aid group and the diplegia group, but there was no difference in the endurance index between them. PCI had a significantly positive correlation with the 10 m walking time. However, PCI did not correlate with repetitions and difference in heart rate between before and after standing ups. From these results, it was concluded that the contracture, muscles weakness in the lower limbs, had a strong influence on ambulation level and energy expenditure in spastic CP. Key words: Spastic CP, Walking duration, Physical fitness. (This article was submitted Oct. 5, 1997, and was accepted Jan. 20, 1998) INTRODUCTION The improvement of movement in children with cerebral palsy is closely related to the expansion of their ordinary mobility, and the achievement to a practical level of walking ability is important. Among children with cerebral palsy who live in our hospital, some are extremely fatigued after walking a few hundred meters or cannot walk continuously. The cause of the deterioration of walking duration is assumed to be reduction of lower limb and trunk functions due to joint deformity, spasm and reduced physical fitness resulting from little chance to walk long distances 1). The purpose of this study was to clarify the major factors of the deterioration of walking ability in children with spastic cerebral palsy, all of whom were inpatients in our hospital. SUBJECTS Eighteen children with cerebral palsy who could communicate and continue to walk for over five minutes were included in this study [10 boys and 8 girls, mean age 12.7 (9 yrs 14 yrs)]. Their types
2 J. Phys. Ther. Sci. Vol. 10, No. 1, 1998 Table 1. Subjects Age (yrs) 12.7 (9 14) Sex boy 10 girl 8 Type of ambulation independent walking 6 crutch walking 6 wheeled walker 6 diagnosis spastic diplegia 13 spasitic hemiplegia 5 Table 2. Exercises Standing up from a table Walk a straight line Exercises and indexes Indexes Repetitions of standing up Endurance index = (repetitions / sum of heat rate) 100 PCI = (HW-HR)/s HW: heart rate after walking (bpm) HR : heart rate at rest (bpm) s : average speed (m/min) 10 m walking time (sec) of ambulation were as follows: six independently walking children, six could walk with the help of crutches, and six could walk with the help of a wheeled walker. Thirteen children had spastic diplegia and five children had spastic hemiplegia (Table 1). METHODS The children were assigned two exercises, and from these four indices were obtained [repetitions of standing up, endurance index, physiological cost index (PCI) and the time required to walk 10 m] (Table 2). The first exercise was standing up from a table with a height of 30cm and the second exercise involved walking on a flat and level surface. In the first exercise, children stood up from a table which was placed between parallel bars and returned to the sitting position supporting themselves with their upper limbs. The height of the bars was set such that each child raised their arms horizontally. This exercise was repeated for 3 minutes, and the children were instructed to perform the exercise as quickly as possible. Repetitions of standing up were counted, and to monitor the reaction of the cardio-pulmonary system the endurance index was calculated from the following formula: Endurance index = repetitions of standing up/ sum of heart rate at three different times, 1 1.5 minutes, 2 2.5 minutes, 3 3.5 minutes after the exercise was completed. In the second exercise, the childred were instructed to walk a straight line of 50 m at a comfortable speed for 3 minutes and PCI was calculated from the following formula: PCI = (heart rate after walking - heart rate at rest)/average speed 4) The time required to walk 10 m was also noted. Walking was perfomed at a comfortable speed to Table 3. Classification of subjects minimize the risk of falling down. In this study, we used the pulse to determine heart rate due to restrictions imposed by the equipment available. While walking, children were allowed to use crutches, wheeled walkers, and orthoses which they used in their everyday life. ANALYSIS The subjects were classified (Table 3) according to differences in ambulation (independent walking group, walking aid group) and differences in palsy (diplegia group, hemiplegia group). The correlation of the indices among these groups were investigated, and the t-test was used for comparison among groups in each classification. RESULTS Age (yrs) Sex 1. Type of palsy boy girl diplegia group (n=13) 12.8 (9 14) 8 5 hemiplegia group (n=5) 12.4 (9 14) 2 3 2. Type of ambulation boy girl independent 13.2 (9 14) 3 3 walking group (n=6) walking-aid group (n=12) 12.5 (9 14) 7 5 1. Correlation among indices 1) Analysis with the different types of ambulation. There was no correlation between PCI and the endurance index in the independent walking group and the walking-aid group (Fig. 1). Similarly there was no correlation between PCI and the repetitions of standing up in either group. However, between the 10 m walking time and
3 Fig. 1. Correlation between PCI and endurance index in the different types of ambulation. Fig. 2. Correlation between the walking time of 10 m and endurance index in the different types of ambulation. Fig. 3. Correlation between the 10 m walking time and repetitions of standing in the different types of ambulation. Fig. 4. Correlation between PCI and endurance index in the different types of palsy. (Fig. 4). However, there were negative correlations between the 10m walking time and the repetitions of standing up in both groups (Fig. 5). Fig. 5. Correlation between the 10 m walking time and repetitions of standing in the different types of palsy. the repetitions of standing up, there were negative correlations in both groups (Fig. 3). 2) Analysis with the different types of palsy There were no correlations between PCI and the endurance index or the repetitions of standing up in the diplegia group and the hemiplegia group 2. Comparison of the two groups in each classifications 1) Comparison of the independent walking group and the walking-aid group. The independent walking group showed significantly lower values in PCI, and a shorter 10 m walking time than the walking-aid group (Table 4). 2) Comparison of the diplegia group and the hemiplegia group. The hemiplegia group showed significantly lower values in PCI, and a shorter 10 m walking time than the diplegia group (Table 5). DISCUSSION Physiological cost index is often used for evaluat-
4 J. Phys. Ther. Sci. Vol. 10, No. 1, 1998 Table 4. Comparing the independent walking group and the walking aid group Independent walking group (n=6) Walking-aid group (n=12) p value Repetions of standing-up 65.2 ± 18.2 63.3 ± 23.5 n.s. Endurance index 49.2 ± 13.9 45.0 ± 18.9 n.s. PCI 0.21 ± 0.1 0.6 ± 0.22 <0.001 10 m walking time 8.1 ± 2.0 14.5 ± 3.8 <0.001 mean ± standard deviation, n.s.: not significant. Table 5. Comparison of the diplegia group and the hemiplegia group Diplegia group (n=13) Hemiplegia group (n=5) p value Repetion of standing up 66.0 ± 21.0 58.0 ± 24.1 n.s. Endurance index 47.3 ± 16.1 43.9 ± 21.9 n.s. PCI 0.55 ± 0.26 0.28± 0.16 <0.001 10 m walking time 13.6 ± 4.4 9.24± 3.2 <0.001 mean ± standard deviation, n.s.: not significant. ing the energy consumption efficiency for walking in hemiplegia patients 5 8). In this study, we applied this index to children with cerebral palsy. We also investigated the relationship to standing up ability and variations in heart rate during movement. In differences of ambulation and palsy, there were no correlations between PCI and the endurance index or the repetition of standing up. The endurance index was defined based on the formula for calculating the Harbad step test 9). However, it is very difficult to step up and down on a table for children with cerebral palsy. Kubota, et al. 2) and Iwatsuki, et al. 3) reported a relationship between the endurance index which was calculated from basic movement over a specified period and physical fitness. Therefore, standing up from a table was used instead of stepping up and down in this study. A lack of correlation between PCI and the endurance index, or the repetition of standing up indicates that physical fitness has only a minimal effect on the reduction of energy consumption efficiency while walking. The independent walking group showed significantly lower values in PCI and the 10 m walking time than the walking-aid group. Therefore it is assumed that the functions of the lower limbs and the trunk might markedly affect the energy consumption efficiency while walking. On the other hand, there was a negative correlation between the 10 m walking time and the repetitions of standing up. Some investigators have reported that the 10 m walking time indicates walking coordination 3). Therefore it was suggested that standing up training leads to improvement of walking ability indirectly and is a useful exercise when space is limited. The results of this study indicate that the deterioration of walking duration in children with cerebral palsy might be caused by problems in walking coodination and stability due to joint deformity, spasm, or muscle weakness, rather than reduction of respiratory-circulatory function. Therefore, it is considered that training for the purpose of maintaining the joint function and muscular strengthening are also worthy for children with spastic cerebral palsy. However, children who live in hospitals are likely to have few chances to walk. Therefore it will be necessary to give children the chance to walk longer distances walking both indoors and outdoors for health maintenance, adaptation to the external environment, and social experience 10, 11). In addition, the method used to determine heart rate in this study was the easiest to use in daily exercise, but this should be investigated again using more sophisticated methods and equipment. REFERENCES 1) Katsumi M, et al: An applied gait training of disabled children with spastic paralysis and its evaluation. Sogo Rehabilitation 18 (1): 39 44, 1990
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