tested on a force platform in four different stances. The experimental group then participated in a daily exercise program of activities traditionally used to facili-.
Effect of an Exercise Program on the Static Balance of Deaf Children SUSAN K. EFFGEN, MMSc Deaf children show subnormal performance on standard tests of static balance. This study investigated the effect of a 10-day exercise program of static balance activities on the static balance ability of severely deaf children. A pretestposttest control group design was used. The subjects, 49 deaf children, were tested on a force platform in four different stances. The experimental group then participated in a daily exercise program of activities traditionally used to facilitate balance ability. A comparison of the change in steadiness scores between the control and experimental groups revealed no significant difference in static balance ability as measured by degree of sway. However, the length of time that children in the experimental group could stand on one leg increased significantly. The lack of improvement in the amount of sway after use of this widely accepted therapeutic program serves to highlight the need for further investigation of the effect of any exercise program on static balance ability. Key Words: Kinesthesia, Deafness, Exercise therapy.
Children who are deaf from birth or early childhood are known to have some degree of balance impairment.1"5 This impaired balance may affect the acquisition of other motor skills or interfere with visual-perceptual-motor development and sensory integration. In an effort to improve the balance of deaf children, physical therapists, physical educators, and educators of the deaf have developed various remedial programs. Unfortunately, reliable data validating the effectiveness or lack of effectiveness of these remedial programs are not available. The purpose of this study was to investigate the effect of an exercise program of static balance activities on the static balance ability of severely deaf children, ages 7 to 10 years. LITERATURE REVIEW Balance is defined as a state of action and reaction between two or more parts or organs of the body.6 Static balance as required for normal standing is the ability to maintain the body equilibrium in some fixed posture. The mechanisms involved in static balance were best summarized by Bannister.7 He noted that normal standing required 1. sufficient power in the muscles of the lower limbs and trunk to maintain the body erect. Ms. Effgen is Assistant Professor, Department of Physical Therapy, College of Allied Health Sciences, Georgia State University, Atlanta, GA 30303 (USA). Portions of this study are contained in a thesis written by Ms. Effgen in partial fulfillment of the requirements for a Master of Medical Science Degree at Emory University, Atlanta, GA. This article was submitted April 1, 1980, and accepted December 9, 1980.
Volume 61 / Number 6, June 1981
2. normal postural sensibility to convey information concerning position. 3. normal impulses from the vestibular labyrinth concerning position. 4. a central coordinating mechanism, the chief part of which is the vermis of the cerebellum. 5. the activity of higher centers concerned in the willed maintenance of posture. These five areas all play a vital role in maintenance of static balance. Little is known, however, about the functioning and relationship of these mechanisms in deaf children. About half of all deaf children have vestibular impairment.8-10 Inasmuch as the vestibular apparatus triggers the vestibular reflex mechanisms that attempt to stabilize the eyes, head, and body in space, impairment of this mechanism will also affect postural sensibility. Thus, many deaf children have a known impairment of at least two, if not more, of the mechanisms Bannister considers necessary for normal static balance. As a result of the impairment of these mechanisms, literature to date agrees that the deaf display inferior static and dynamic balance compared to normal, hearing subjects.1-5, 9 Investigators also agree that those whose cause of deafness was meningitis have the most serious balance problems1, 4 and that balance ability decreases in the dark and when the eyes are shut.2 Some investigators have found deaf girls to sway more than deaf boys.3, 11 A more recent study by Lindsey and O'Neal found no difference in performance in static or dynamic balance between deaf girls and deaf boys.2
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Despite the evidence of deficiency in the balance ability of deaf children and the frequent attempts to improve their balance ability, studies on the effect of remedial balance programs with deaf children are lacking. The few studies of the effect of remedial balance programs that do exist are of normal adults and provide no definite conclusions. This investigation considered both sway and length of time standing on one leg as measures of static balance. The specific question addressed was, Does an exercise program of static balance activities improve the static balance ability of deaf children?
METHOD Subjects Subjects were 49 students attending a nonresidential school for the deaf. Intelligence quotient scores for the subjects were not available; however, all subjects were able to follow the simple instructions given. Degree of hearing loss was obtained from records of audiometric testing. All of the subjects had either severe or profound hearing losses, greater than 75 dB. The students' yearly medical records and histories were reviewed to ensure the absence of secondary neurological deficits. Each student's gross motor ability was also observed to further ensure general normality. The cause of deafness, if known, was recorded for each subject, but no attempt was made to control for cause of deafness. Age range of the students was 7.0 to 11.0 years of age. A pretest-posttest control group design was used. Subjects were assigned to experimental and control groups by stratified, random sampling according to sex and age. The sampling distribution is presented in Table 1.
Instrumentation Static balance was measured by a force platform.* The platform measures the forces exerted by the * Multicomponent Measuring Platform. Kristal Instrumental Corp, 75 John Glenn Trail, Amherst, NY 14120.
TABLE 1 Sampling Distribution of Age and Sex for Experimental and Control Groups Experimental Group
Control Group
Age Male
Female
Male
Female
7 8 9 10
1 3 4 7
2 2 0 6
1 4 3 6
2 1 0 7
Total
15
10
14
10
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subject by means of quartz crystals. The crystals produce electrical charges proportional to the amount of force each one undergoes. These charges are converted into direct current voltages by the charge amplifiers for recording on a frequency modulation tape. Excursions or displacements in the anterior-posterior direction, designated as X, and in the mediallateral direction, designated as y, were recorded. The tape-recorded data were converted to digital form and sampled at a rate of 20 per second using an analog-to-digital converter and a PDP-8/E computer. The measure of stance in both the X and Y directions for each trial was the average of the absolute values of the deviations of the force signal about the mean. It was mathematically represented by
where n was the number of samples in the trial period. The measure was referred to as the steadiness score and was given in newtons. The computer did not sample over one volt; it would list all forces over one volt as saturations and would sample all data points under one volt. Therefore, if a subject fell off the force platform, his fall would not affect the steadiness score for the time he did hold the test position. Reliability of the instruments was maintained by a daily calibration procedure.
Data Collection Initially, all students in the primary grades at the school were given the pretest. The pretest and posttest consisted of having the subject stand on the force platform in each of the following test positions: 1. Stand, feet together, medial borders touching, eyes open. 2. Stand, feet together, medial borders touching, eyes closed and covered. 3. Stand on right leg, unsupported, eyes open. 4. Stand on left leg, unsupported, eyes open. As the subject entered the testing room, he was asked to remove his shoes, socks, and hearing aid. In order to randomize the possible effect of sequence of stance positions, the subject then selected one of 24 index cards with a different sequence of stance positions listed on each. Testing instructions were explained using total communication to assure understanding of the activities required. Total communication consisted of sign and oral language as well as demonstration. Instructions were repeated until the subject knew what was to be expected, as outlined by Long.3 The investigator initially demonstrated the stance position directly in front of the subject and then
PHYSICAL THERAPY
TABLE 2 Mean Change in Steadiness Scoresa of the Experimental and Control Groupsb Anterior-Posterior Sway (X) Test Position
Medial-Lateral Sway (Y)
n s
Eyes Open Experimental Control Eyes Closed Experimental Control Right Leg Experimental Control Left Leg Experimental Control
s
25 24
0.42 0.00
2.38 0.37
0.24 -0.06
1.32 0.31
25 24
0.14 0.08
0.50 0.81
0.06 -0.02
0.54 0.74
24 c 23 c
0.06 0.51
3.10 1.11
0.66 1.12
2.23 5.51
23 c 21 c
0.56 0.40
2.19 3.35
-0.37 0.43
2.40 3.05
a
Measured in newtons. No significant differences in any of the test positions, in either direction, between control and experimental groups. c n is reduced because not all subjects could maintain test position. b
moved to the subject's left side. Inasmuch as verbal clues could not be optimally used, the investigator had to stay within the subject's visual field. The subject viewed the unobstructed, general environment that recent investigators consider optimal for best stance.12, 13 The subject was to stand on the force platform for 30 seconds in each test position. The investigator timed the trial and gave instructions while the research associate operated the apparatus. The 49 students who met the criteria of age, degree of hearing loss, and no apparent secondary neurological problems were then randomly assigned into control and experimental groups. The procedure for the posttest was identical to that used in the pretest, and the same stance sequence was used on the posttest that each individual subject used on the pretest. Exercise Program The exercise program was given to the experimental group following the pretest and was conducted daily for 10 consecutive school days. The 15-minute static balance exercise program was selected because of its frequent use to improve balance ability. The program, outlined by Armheim and Pestolesi,14 consisted of the following: 1. Stand on toes, feet apart. 2. Stand on toes, feet together. 3. Stand on right foot unsupported, with left foot behind right knee. 4. Stand on left foot unsupported, with right foot behind left knee. 5. Stand with right heel touching left toe, feet in a straight line. Volume 61 / Number 6, June 1981
Exercise instructions were given in total communication. Each exercise was first demonstrated and then done with the group. Each exercise was done three times to the count of 10 with a brief pause between each repetition. Approximately a one-minute rest period occurred between exercises, while the next exercise was demonstrated. Students were asked to remove shoes and socks before beginning the exercises. Daily attendance was taken. If a student was absent on one day, the next day he would stay after the exercise program and would go through the exercise program again, individually with the investigator. No student was absent for more than two days, and no student was absent for two consecutive days. While the experimental group was engaged in the exercise program, the control group engaged in their normal classroom activity (free play). Data from the steadiness scores and length of time stood on one foot were subjected to Student's t tests to determine any significant differences. RESULTS When intersex data were compared, the mean pretest steadiness scores and the mean change in steadiness scores were not significantly different between the sexes. Therefore, the male and female data were combined in further analysis. Comparison of pretest scores between the four test positions revealed a significant (p < .05) difference in the amount of sway when standing on one leg versus standing on two legs. No significant difference was found between the eyesclosed versus eyes-open test positions. Throughout the data, large standard deviations among subjects were noted. However, individual variations in test-retest situations were relatively stable
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and pretest scores between the experimental and control groups were not statistically different. Differences in the mean change in steadiness scores between the experimental and the control groups were not significant (Tab. 2) at the p < .05 level in any of the test positions, in either direction. The data were not subjected to further statistical analysis because of the lack of significant differences. The mean change in the length of time stood on one leg was significantly (p < .025, right leg; p < .01, left leg) different between the experimental and control groups (Tab. 3). DISCUSSION The significant difference in the length of time stood on one leg reflects a quantitative improvement in stance, whereas the lack of significant improvement in the amount of sway indicates that the quality of stance did not improve. The instrumentation used in this investigation was sensitive enough to detect even the slightest change in static balance ability and was certainly a more sensitive tool than the more frequently used, simplistic measures of static balance. Because of the extreme sensitivity of the instrumentation and the use of a very common, widely accepted remedial exercise program, the lack of improvement in sway by the experimental group is of serious concern. Two possible explanations for this lack of improvement are that our traditional exercise programs are indeed ineffective and that perhaps static balance ability cannot be improved in deaf children. In addition to these two primary possible causes of failure, several others arise. First, the duration of the exercise program may have been insufficient to produce significant improvement. However, even given the short duration of the program, the instrumentation used in this study was sensitive enough to detect the slightest improvement. Second, the children in this study were previously exposed to a physical education program and this might have maximized
their potential. Third, preschool-age children may also benefit more readily from the program. These possible explanations for the lack of improvement in sway by the experimental group still leave the question open as to whether such a common exercise program is indeed ever effective and, if so, under what conditions. When using the traditional measure of static balance—length of time stood on one leg—significant improvement by the experimental group was observed. Perhaps this quantitative method of measuring static balance is responsible for the present design and emphasis of most programs to improve static balance. The question is, however, Of what clinical importance is the ability to increase the length of time stood on one leg if the person has excessive sway and has serious difficulty walking on unstable surfaces or in the dark? We need to look further into the neurological basis of balance and to design programs to improve the psychomotor integration of all factors affecting balance. Programs that merely practice the desired terminal behavior might be the least effective method of clinically improving the terminal behavior. Also, balance should be controlled at an automatic level and not at a conscious level. Increasing the length of time stood on one leg probably represents an improvement in balance ability caused by increased consciousness but not an improvement at a subconscious level. This increased conscious effort required to stand might produce a secondary deficit, in that recognition of meaningful stimuli in the environment is reduced. The effect of any remedial program on static balance ability in deaf or hearing subjects must be carefully explored. We cannot continue to use programs whose benefit is entirely unknown. Research is needed on the effectiveness of any type of remedial program, the necessary duration of a program, the most responsive age and diagnostic groups to work with, and a practical, clinical means of measuring not only quantity of improvement in static balance but also of quality.
TABLE 3 Mean Change in Length of Timea Stood on One Leg and Results of t test Test Position
n
s
t
Right Leg Experimental Control
25 23 b
1.53 -2.75
7.72 6.68
2.04 c
Left Leg Experimental Control
25 22b
3.68 -3.41
10.20 8.10
2.50 d
a b c d
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Measured in seconds. n reduced because all subjects could not maintain test position. p < .025. p < .01. PHYSICAL THERAPY
CONCLUSION
This study suggests that an exercise program of static balance activities can influence static balance in deaf children by increasing the length of time they can stand on one leg. However, the program did not improve the quality of static balance, in terms of amount of sway, in deaf children. We should, therefore, carefully assess all of our balance programs to
determine if they are effectively meeting our desired objectives and not substituting quantity for quality or merely increasing conscious awareness of balance, which has little functional benefit. Acknowledgments. I wish to express my appreciation to Pamela Catlin, EdD, James Malone, and Raymond Burdett, PhD.
REFERENCES 1. Myklebust HR: The Psychology of Deafness, ed 2. New York, NY, Grune & Stratton, Inc, 1964, pp 180-201 2. Lindsey D, O'Neal J: Static and dynamic balance skills of eight year old deaf and hearing children. Am Ann Deaf 121: 4 9 - 5 5 , 1976 3. Long J: Motor abilities of deaf children. In: Contribution to Education, no. 514. New York, NY, Columbia University Teachers' College, 1932 4. Boyd J: Comparison of motor behavior in deaf and hearing boys. Am Ann Deaf 12:598-605, 1967 5. Grimsley JR: The Effect of Visual Cueness and Visual Deprivation Upon the Acquisition and Rate of Learning of a Balance Skill Among Deaf Individuals. Dissertation. Athens, GA, University of Georgia, 1972 6. Stedman's Medical Dictionary, ed 21. Baltimore, MD, Williams & Wilkins Co, 1966, p 182 7. Bannister R: Brain's Clinical Neurology, ed 3. New York, NY, Oxford University Press, Inc, 1969, pp 5 1 - 5 4 , 102 8. Rapin I: Hypoactive labyrinths and motor development. Clin Pediatr 13:922-937, 1974
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9. Arnvig J: Vestibular function in deafness and severe hardness of hearing. Acta Otolaryngol 4:283-288, 1955 10. Rosenblüt B, Goldstein R, Landau WM: Vestibular responses of some deaf and aphasic children. Ann Otol Rhinol Laryngol 69:747-755, 1960 11. Myklebust HR: Significance of etiology in motor performance of deaf children with special reference to meningitis. Am J Psychol 59:249-258, 1946 12. Begbie GH: Some problems of postural sway. In deReuck AVS, Knight J (eds): Ciba Foundation Symposium: Myotatic, Kinesthetic and Vestibular Mechanisms. Boston, MA, Little, Brown & Co, 1967, pp 8 0 - 1 0 4 13. Weissman S, Dzendolet E: Effects of visual cues on standing body sway of males and females. Percept Mot Skills 34: 9 5 1 - 9 5 9 , 1972 14. Armheim DD, Pestolesi RA: Developing Motor Behavior in Children. Saint Louis, MO, C.V. Mosby Co, 1973, pp 1 0 9 112
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