Perceptualand Motor Skillr, 1990, 70, 883-888.
O Perceptual and Motor Skills 1990
COMPARATIVE STUDY O F T H E DYNAMIC, STATIC, A N D ROTARY BALANCE O F DEAF AND H E A R I N G CHILDREN ' G. WILLIAM GAYLE AND ROBERTA L. POHLMAN Wright State Uniuersio Summary.-The purpose of the present study was to measure the dynamic, static and rotary balance of deaf and hearing children. 20 deaf and 20 normal hearing students matched for mean age of 123k5.9 or 5.6 mo. and sex (11 boys, 9 girls) performed three tests of balance. A series of Wilcoxon signed-ranks tests and a Kendall Tau were applied to assess whether balance was affected in sensorineural deafness and to assess whether age and sex were factors in over-all balance, respectively. Significant differences were noted between groups for dynamic balance and rotary balance. Although not sigdicant, there was a difference of 57.8% in number of trials for successful completion of static balance in favor of the hearing children. In the present study, over-all balance in deaf children was significantly inferior to the balance in hearing children. Knowledge of these differences may aid those working with deaf children in physical education.
Balance is considered an important orthogonal component of all movement required by everyday life. Good motor performance requires the control of time, space, and often objects. and balance is a necessary prerequisite for this control. Physical educat~onand sport skills place a high premium on balance to perform a particular s l d or movement successfully. During 1986-87 an estimated 66,671 deaf or hearing impaired students between the ages of 3 and 2 1 yr. (U.S. Dept. of Education, 1988) were in special education classes. Today, more attention is given hearing-impaired students' motor skills in regular physical education. Because the characteristics of vestibular function and balance skills of deaf children may differ from those of hearing children, there is growing interest in comparing these two groups on balance during mainstreamed physical education classes. When comparing measures of physical fitness, Winnick and Short (1986) noted that with the possible exception of sit-ups, hearing impaired populations may be evaluated against the same physical fitness standards as hearing populations. However, other researchers have found that deaf individuals are inferior to hearing subjects in motor development (Butterfield, 1986; Vance, 1968; Wiegersma & Van Der Velde, 1983), static and dynamic balance (Boyd, 1967; Brunt & Broadhead, 1982; Lindsay & O'Neal, 1976; Long, 1932), and postrotary nystagamus (Myklebust, 1946; Potter & Silverman, 1984). Investigations regarding age, sex, etiology, and initial onset of
'Address correspondence to G. W. Gayle, Ph.D., Department of Health, Physical Education and Recreation, College of Education and Human Services, Wright State University, Dayton, Ohio 45435.
884
G . W. GAYLE & R. L. POHLMAN
vestibular lesion have used a range of methods producing inconsistent results, suggesting the need for further investigation. The purpose of this investigation then was to examine the effects of a sensorineural hearing loss upon the balance in deaf children.
METHOD Subjects Twenty deaf and 20 normal hearing students were recruited and matched according to age (deaf: M = 123 + 5.9 mo.; hearing: M = 123 5.6 mo.) and sex (boys = 11; girls = 9 in each group). One hundred percent of the deaf subjects had hearing losses of 70 dB or greater, and met the Wisconsin Department of Public Instruction criteria for placement as a severely handicapped hearing child. Etiologies included 10 idiopathic, 4 meningitis, and 6 rubella. All subjects were asymptomatic of disease, free from other handicapping conditions and received parental consent. All subjects were enrolled in regular physical education classes. Hearing loss and topographc data were obtained from the subjects' medical files. Procedure Balance testing.-Each subject was individually and randomly administered three balance tests in an enclosed room. All external stimuli were minimized during test administration. Each subject was provided verbal instructions and a researcher demonstrated each test item. In addition, total communication (manual and verbal) and written directions were used with hearing-impaired subjects. Dynamic balance was assessed using a balanciometer (Haymes & Dickinson, 1980). Time balanced during the 1-min. trial was measured by an interval timer, controlled by two microswitches secured at both lateral borders of a 20-in. wide x 30.5-in. long x 6.5-in. deep frame. A footplate, which the subject strived to keep level, was mounted on an anterior posterior axle set in ball bearings. The lateral edges of this footplate would press on the microswitches, stopping the interval timer (Lafayette Instrument Company of Lafayette, Indiana, Model No. 5661ADW) whenever balance could not be maintained; however, the manual timer continued to run for the complete interval. Prior to the test, subjects were provided an habituation session on the balance platform. With the balanciometer set at zero and the manual timer off, the subjects mounted the balance platform. Upon prompting by the examiner, the manual timer was started, and the subject began balancing. While balancing on both feet, each subject attempted to avoid lateral shifts and keep the platform level. After 1 min., the timer was stopped, a direct reading of the meter was observed; and the number of seconds balanced during the period was recorded. Static balance was evaluated by using test Item 3 of the Lincoln-Oser-
BALANCE OF DEAF AND HEARING CHILDREN
885
etsky Motor Development Scale (Sloan, 1954) with two adaptations. For the first adaptation, the free leg was repositioned from the sole of the foot placed against the inside of the supporting knee, to a flexed position at the knee, and extended toward the back at 90°. A second adaptation required all subjects to begin on the right foot, with trials continuing until the subject showed ability to stand for 25 sec. or failed on 40 trials (20 for each foot) (Worchel & Dallenbach, 1950). After a 30-sec. rest, the test was repeated with the weight on the left leg. Rotary balance (postrotary nystagmus time) was assessed by rotating the subjects clockwise and counterclockwise on alternate trials, with eyes closed, head upright (30' lean forward from vertical) and back straight. Rotation was performed by a hand-operated rotary chair (360') at a rate of 10 times in 20 sec. and manually stopped. The examiner then timed and recorded the duration of postrotary horizontal nystagamus. Each subject received 1 min. between tests to prevent possible carryover of vertigo (MykIebust, 1946).
RESULTS AND DISCUSSION To answer the question of whether balance was affected by sensorineural deafness, a series of Wilcoxon signed-rank tests were performed on the measurements of static balance, dynamic balance, rotary balance to the right, and rotary balance to the left. This statistical test was considered appropriate as sample groups were not independently selected. Because measurements of static balance on the right and left foot were not randomized, the scores were summed before statistical analysis. Alpha level was set a priori to .05. To control for alpha inflation, the Bonferroni technique was applied (alpha level divided by number of comparisons). This technique resulted in an over-all alpha level of ,013. The null hypothesis, that there would be no significant differences between children with normal hearing and children who were deaf, was rejected for three of the four balance tests (Table 1). Clockwise rotary balance, counterclockwise rotary balance, and dynamic balance significantly favored the normally hearing children (Wilcoxon matched-pairs signed-ranks test: rotary balance right, T = 37, p = .0001; rotary balance left, T = 37, p = .0001; dynamic balance, T = 37, p = .01). Static balance was not significantly different for the two groups ( T =37, p = .02). Many researchers have noted the inferiority of the deaf to hearing children on dynamic balancing acts (Long, 1932; Worchel & Dallenbach, 1950; Lindsey & O'Neal, 1976; Brunt & Broadhead, 1982). Balancing could be considered a series of ballistic responses to counter feedback signals of off balance. Deafness, as a result of impaired functioning of the utricle and saccule, will affect static and dynamic balance (Guyton, 1976). Brunt, Layne, Cook, and Rowe (1984) stated that, if upright posture is disturbed, the body executes an automatic postural response, which is reflexive in nature. Both visual and vestibular feedback
886
G. W. GAYLE & R. L. POHLMAN
are responsible for this reflex action to maintain balance. They believe that the inability to balance dynamically is a result of a delay in motor response It is believed as measured in the posterior leg muscles by ele~trom~ography. that with experience, some children could develop postural strategies to overcome difficulties during anticipated unbalance. The results indicate that overall, the deaf children had not yet learned to compensate for the anticipated unbalance during the dynamic balance test. TABLE 1 SUMMARY OF GROUPCHARACTERISTICS AND STATISTICAL ~SLKTS Group Characteristics Age (mo.) Deaf Group Hearing Group Sex Deaf (n = 20) Hearine (n = 20) Balance Measurement
M
SEM
123 123
5.9 5.6
Boys = 11, Girls = 9 Bovs = 11, G i l s = 9
M
SEM
P
Static Balance (Trials) 6.4 2.03 .02 Deaf 2.7 0.46 Hearing Dynamic Balance, sec. Deaf Hearing Rotary Balance Right, sec. 0.95 ,001 2.5 Deaf 19.4 0.94 Hearing Rotary Balance Left, sec. Deaf Hearing Note.-Alpha level set at ,013 based on a Bonferroni adjustment to protect the over-all Type I error rate (alpha level divided by number of tests, .05/4).
The mean duration of postrotary nystagamus was below that of hearing children, agreeing with previous investigations (Potter & Silverman, 1984; Kimball, 1981). Previous research has showed that rotary balance is controlled by the semicircular canals (Worchel & Dallenbach, 1950). Since our deaf subjects made significant abnormal responses to rotary balance, lesions to the semicircular canals may have existed, warranting further investigation. The mean number of trials for successful completion of the static balance maneuver ( 6 . 4 ~ 2 . and 1 2.7 ~ 0 . 4 6 a, difference of 57.8%) for the deaf and normally hearing children, respectively, were not significant. These results disagree with a report by Lindsey and O'Neal (1976) who reported that deaf chddren failed significantly more often on the test of static balance than
BALANCE O F DEAF AND HEARING CHILDREN
887
did normally hearing children. However, this increase in number of trials required by the deaf children for completion of the static balance test seems to support data reported by Lindsey and O'Neal (1976). Sex was not a significant factor in over-all balance for either group. Butterfield and Ersing (1986) reported s i d a r findings in a study on static and dynamic balance in children ages 3 to 14 yr. To determine whether age was a factor in over-all balance, a Kendall Tau correlation coefficient was performed on the various balance measurements. Significant differences were noted for dynamic and static balance (dynamic balance: r = 0.55, R 2= 0.30, p = .00001; static balance: r = -0.37, R* = .14, p = .002). The children in both groups demonstrated better balance as they increased in age, supporting the work of Brunt and Broadhead (1982) and of Butterfield and Ersing (1986). As children increase in age, maturation and additional opportunities to practice these balance movements may account for this significant difference. No association was found in the measurement of involuntary rhythmic oscillation of the eyes (rotary balance right: p = .45; rotary balance left: p = .37). This may reflect that rotary balance is the function of optimal semicircular canal performance and maturation of the central nervous system, not exercise or practice. The results of this experiment indicate that the over-all balance in deaf children is significantly inferior to the balance in hearing children. However, as stated by Wiegersma and Van Der Velde (1983), deficiencies in balance may be due to neurological defects or problems in motor control. Knowledge of vestibular lesion topographic and electromyographic (EMG) analysis in the assessment of balance, may contribute to greater understanding of balance and movement as related to the autonomous entities of an individual's vestibular system. REFERENCES BOYD,J. (1967) Comparison of motor behavior in deaf and hearing boys. American Annals of the Deaf, 112, 598-605. BRUNT, D., & BROADHEAD, G. D. (1982) Motor traits of deaE children. Research Quarterly for Exercise and Sport, 53, 236-238. BRUNT,D., LAYNE,C. S., COOK,M., & ROE, L. (1984) Automatic posmal responses of deaf children from dynamic and static positions. Adapted Physical Activity Quarterly, 1, 247-252. BUTTERFIELD, S. A. (1986) Gross motor profiles of deaf children. Perceptual and Motor Skills, 62, 68-70. BUTTERFIELD,S. A,, & ERSING, W. F. (1986) Influence of age, sex, etiology, and hearing loss on balance performance by deaf children. Perceptual and Motor Skills, 62, 659-663. GUYTON,A. C. (1976) Textbook of rnedicalphysiology. Philadelphia, PA: Saunders. HAYMES,E. M., & DICKINSON, A. L. (1980) Characteristics of elite male and female ski racers. Medicine and Science in Sports and Exercise, 12, 153-158. KIMBALL,J. G . (1981) Normative comparison of the Southern California postrot nystagamus test: Las Angeles vs Syracuse data. American Journal of Occupational z e r o W , 35, 21-25.
888
G . W. GAYLE & R. L. POHLMAN
LINDSEY, D., & O'NEAL,J. (1976) Static and dynamic balance skills of eight year old deaf and hearing children. American Annals of the Deaf, 121, 49-55. LONG,J. (1932) Motor abilities of deaf children. New York: Columbia University, Teachers College Contributions to Education No. 514. MYKLEBUST, H. R. (1946) Significance of etiology in motor performance of deaf children with special reference to meningitis. American Journal of Psychology, 59, 249-258. POTTER,C. N., & SILVERMAN, L. N. (1984) Characteristics of vestibular function and static balance in deaf children. Physical Therapy, 64, 1071-1075. SLOAN,W. (1954) The Lincoln-Oseretsky Motor Development Scale. Lincoln, IL: Lincoln State School. Pp. 25-26. U.S. DEPARTMENT OF EDUCATION. (1988) Tenth annual report to Congress. Washington, DC: Author. VANCE,P C. (1968) Motor characteristics of deaf children. Dissertation Abstracts International, 29, 1145-1146A. WIEGERSMA, P H., & VANDER VELDE,A. (1983) Motor development of deaf children. Jor~rnal of Child Psychology and Psychiatry, 24, 103-111. WINNICK,J. P, & SHORT,F. X. (1986) Physical fitness of adolescents with au&tory irnpairments. Adapted Physical Activity Quarterly, 3, 58-66. WORCHEL, P., & DALLENBACH, K. M. (1950) Vestibular sensitivity in the deaf. American Journal of Psychology, 63, 161-175.
Accepted April 10, 1990.
O Perceptual and Motor Skills 1990
COMPARATIVE STUDY O F T H E DYNAMIC, STATIC, A N D ROTARY BALANCE O F DEAF AND H E A R I N G CHILDREN ' G. WILLIAM GAYLE AND ROBERTA L. POHLMAN Wright State Uniuersio Summary.-The purpose of the present study was to measure the dynamic, static and rotary balance of deaf and hearing children. 20 deaf and 20 normal hearing students matched for mean age of 123k5.9 or 5.6 mo. and sex (11 boys, 9 girls) performed three tests of balance. A series of Wilcoxon signed-ranks tests and a Kendall Tau were applied to assess whether balance was affected in sensorineural deafness and to assess whether age and sex were factors in over-all balance, respectively. Significant differences were noted between groups for dynamic balance and rotary balance. Although not sigdicant, there was a difference of 57.8% in number of trials for successful completion of static balance in favor of the hearing children. In the present study, over-all balance in deaf children was significantly inferior to the balance in hearing children. Knowledge of these differences may aid those working with deaf children in physical education.
Balance is considered an important orthogonal component of all movement required by everyday life. Good motor performance requires the control of time, space, and often objects. and balance is a necessary prerequisite for this control. Physical educat~onand sport skills place a high premium on balance to perform a particular s l d or movement successfully. During 1986-87 an estimated 66,671 deaf or hearing impaired students between the ages of 3 and 2 1 yr. (U.S. Dept. of Education, 1988) were in special education classes. Today, more attention is given hearing-impaired students' motor skills in regular physical education. Because the characteristics of vestibular function and balance skills of deaf children may differ from those of hearing children, there is growing interest in comparing these two groups on balance during mainstreamed physical education classes. When comparing measures of physical fitness, Winnick and Short (1986) noted that with the possible exception of sit-ups, hearing impaired populations may be evaluated against the same physical fitness standards as hearing populations. However, other researchers have found that deaf individuals are inferior to hearing subjects in motor development (Butterfield, 1986; Vance, 1968; Wiegersma & Van Der Velde, 1983), static and dynamic balance (Boyd, 1967; Brunt & Broadhead, 1982; Lindsay & O'Neal, 1976; Long, 1932), and postrotary nystagamus (Myklebust, 1946; Potter & Silverman, 1984). Investigations regarding age, sex, etiology, and initial onset of
'Address correspondence to G. W. Gayle, Ph.D., Department of Health, Physical Education and Recreation, College of Education and Human Services, Wright State University, Dayton, Ohio 45435.
884
G . W. GAYLE & R. L. POHLMAN
vestibular lesion have used a range of methods producing inconsistent results, suggesting the need for further investigation. The purpose of this investigation then was to examine the effects of a sensorineural hearing loss upon the balance in deaf children.
METHOD Subjects Twenty deaf and 20 normal hearing students were recruited and matched according to age (deaf: M = 123 + 5.9 mo.; hearing: M = 123 5.6 mo.) and sex (boys = 11; girls = 9 in each group). One hundred percent of the deaf subjects had hearing losses of 70 dB or greater, and met the Wisconsin Department of Public Instruction criteria for placement as a severely handicapped hearing child. Etiologies included 10 idiopathic, 4 meningitis, and 6 rubella. All subjects were asymptomatic of disease, free from other handicapping conditions and received parental consent. All subjects were enrolled in regular physical education classes. Hearing loss and topographc data were obtained from the subjects' medical files. Procedure Balance testing.-Each subject was individually and randomly administered three balance tests in an enclosed room. All external stimuli were minimized during test administration. Each subject was provided verbal instructions and a researcher demonstrated each test item. In addition, total communication (manual and verbal) and written directions were used with hearing-impaired subjects. Dynamic balance was assessed using a balanciometer (Haymes & Dickinson, 1980). Time balanced during the 1-min. trial was measured by an interval timer, controlled by two microswitches secured at both lateral borders of a 20-in. wide x 30.5-in. long x 6.5-in. deep frame. A footplate, which the subject strived to keep level, was mounted on an anterior posterior axle set in ball bearings. The lateral edges of this footplate would press on the microswitches, stopping the interval timer (Lafayette Instrument Company of Lafayette, Indiana, Model No. 5661ADW) whenever balance could not be maintained; however, the manual timer continued to run for the complete interval. Prior to the test, subjects were provided an habituation session on the balance platform. With the balanciometer set at zero and the manual timer off, the subjects mounted the balance platform. Upon prompting by the examiner, the manual timer was started, and the subject began balancing. While balancing on both feet, each subject attempted to avoid lateral shifts and keep the platform level. After 1 min., the timer was stopped, a direct reading of the meter was observed; and the number of seconds balanced during the period was recorded. Static balance was evaluated by using test Item 3 of the Lincoln-Oser-
BALANCE OF DEAF AND HEARING CHILDREN
885
etsky Motor Development Scale (Sloan, 1954) with two adaptations. For the first adaptation, the free leg was repositioned from the sole of the foot placed against the inside of the supporting knee, to a flexed position at the knee, and extended toward the back at 90°. A second adaptation required all subjects to begin on the right foot, with trials continuing until the subject showed ability to stand for 25 sec. or failed on 40 trials (20 for each foot) (Worchel & Dallenbach, 1950). After a 30-sec. rest, the test was repeated with the weight on the left leg. Rotary balance (postrotary nystagmus time) was assessed by rotating the subjects clockwise and counterclockwise on alternate trials, with eyes closed, head upright (30' lean forward from vertical) and back straight. Rotation was performed by a hand-operated rotary chair (360') at a rate of 10 times in 20 sec. and manually stopped. The examiner then timed and recorded the duration of postrotary horizontal nystagamus. Each subject received 1 min. between tests to prevent possible carryover of vertigo (MykIebust, 1946).
RESULTS AND DISCUSSION To answer the question of whether balance was affected by sensorineural deafness, a series of Wilcoxon signed-rank tests were performed on the measurements of static balance, dynamic balance, rotary balance to the right, and rotary balance to the left. This statistical test was considered appropriate as sample groups were not independently selected. Because measurements of static balance on the right and left foot were not randomized, the scores were summed before statistical analysis. Alpha level was set a priori to .05. To control for alpha inflation, the Bonferroni technique was applied (alpha level divided by number of comparisons). This technique resulted in an over-all alpha level of ,013. The null hypothesis, that there would be no significant differences between children with normal hearing and children who were deaf, was rejected for three of the four balance tests (Table 1). Clockwise rotary balance, counterclockwise rotary balance, and dynamic balance significantly favored the normally hearing children (Wilcoxon matched-pairs signed-ranks test: rotary balance right, T = 37, p = .0001; rotary balance left, T = 37, p = .0001; dynamic balance, T = 37, p = .01). Static balance was not significantly different for the two groups ( T =37, p = .02). Many researchers have noted the inferiority of the deaf to hearing children on dynamic balancing acts (Long, 1932; Worchel & Dallenbach, 1950; Lindsey & O'Neal, 1976; Brunt & Broadhead, 1982). Balancing could be considered a series of ballistic responses to counter feedback signals of off balance. Deafness, as a result of impaired functioning of the utricle and saccule, will affect static and dynamic balance (Guyton, 1976). Brunt, Layne, Cook, and Rowe (1984) stated that, if upright posture is disturbed, the body executes an automatic postural response, which is reflexive in nature. Both visual and vestibular feedback
886
G. W. GAYLE & R. L. POHLMAN
are responsible for this reflex action to maintain balance. They believe that the inability to balance dynamically is a result of a delay in motor response It is believed as measured in the posterior leg muscles by ele~trom~ography. that with experience, some children could develop postural strategies to overcome difficulties during anticipated unbalance. The results indicate that overall, the deaf children had not yet learned to compensate for the anticipated unbalance during the dynamic balance test. TABLE 1 SUMMARY OF GROUPCHARACTERISTICS AND STATISTICAL ~SLKTS Group Characteristics Age (mo.) Deaf Group Hearing Group Sex Deaf (n = 20) Hearine (n = 20) Balance Measurement
M
SEM
123 123
5.9 5.6
Boys = 11, Girls = 9 Bovs = 11, G i l s = 9
M
SEM
P
Static Balance (Trials) 6.4 2.03 .02 Deaf 2.7 0.46 Hearing Dynamic Balance, sec. Deaf Hearing Rotary Balance Right, sec. 0.95 ,001 2.5 Deaf 19.4 0.94 Hearing Rotary Balance Left, sec. Deaf Hearing Note.-Alpha level set at ,013 based on a Bonferroni adjustment to protect the over-all Type I error rate (alpha level divided by number of tests, .05/4).
The mean duration of postrotary nystagamus was below that of hearing children, agreeing with previous investigations (Potter & Silverman, 1984; Kimball, 1981). Previous research has showed that rotary balance is controlled by the semicircular canals (Worchel & Dallenbach, 1950). Since our deaf subjects made significant abnormal responses to rotary balance, lesions to the semicircular canals may have existed, warranting further investigation. The mean number of trials for successful completion of the static balance maneuver ( 6 . 4 ~ 2 . and 1 2.7 ~ 0 . 4 6 a, difference of 57.8%) for the deaf and normally hearing children, respectively, were not significant. These results disagree with a report by Lindsey and O'Neal (1976) who reported that deaf chddren failed significantly more often on the test of static balance than
BALANCE O F DEAF AND HEARING CHILDREN
887
did normally hearing children. However, this increase in number of trials required by the deaf children for completion of the static balance test seems to support data reported by Lindsey and O'Neal (1976). Sex was not a significant factor in over-all balance for either group. Butterfield and Ersing (1986) reported s i d a r findings in a study on static and dynamic balance in children ages 3 to 14 yr. To determine whether age was a factor in over-all balance, a Kendall Tau correlation coefficient was performed on the various balance measurements. Significant differences were noted for dynamic and static balance (dynamic balance: r = 0.55, R 2= 0.30, p = .00001; static balance: r = -0.37, R* = .14, p = .002). The children in both groups demonstrated better balance as they increased in age, supporting the work of Brunt and Broadhead (1982) and of Butterfield and Ersing (1986). As children increase in age, maturation and additional opportunities to practice these balance movements may account for this significant difference. No association was found in the measurement of involuntary rhythmic oscillation of the eyes (rotary balance right: p = .45; rotary balance left: p = .37). This may reflect that rotary balance is the function of optimal semicircular canal performance and maturation of the central nervous system, not exercise or practice. The results of this experiment indicate that the over-all balance in deaf children is significantly inferior to the balance in hearing children. However, as stated by Wiegersma and Van Der Velde (1983), deficiencies in balance may be due to neurological defects or problems in motor control. Knowledge of vestibular lesion topographic and electromyographic (EMG) analysis in the assessment of balance, may contribute to greater understanding of balance and movement as related to the autonomous entities of an individual's vestibular system. REFERENCES BOYD,J. (1967) Comparison of motor behavior in deaf and hearing boys. American Annals of the Deaf, 112, 598-605. BRUNT, D., & BROADHEAD, G. D. (1982) Motor traits of deaE children. Research Quarterly for Exercise and Sport, 53, 236-238. BRUNT,D., LAYNE,C. S., COOK,M., & ROE, L. (1984) Automatic posmal responses of deaf children from dynamic and static positions. Adapted Physical Activity Quarterly, 1, 247-252. BUTTERFIELD, S. A. (1986) Gross motor profiles of deaf children. Perceptual and Motor Skills, 62, 68-70. BUTTERFIELD,S. A,, & ERSING, W. F. (1986) Influence of age, sex, etiology, and hearing loss on balance performance by deaf children. Perceptual and Motor Skills, 62, 659-663. GUYTON,A. C. (1976) Textbook of rnedicalphysiology. Philadelphia, PA: Saunders. HAYMES,E. M., & DICKINSON, A. L. (1980) Characteristics of elite male and female ski racers. Medicine and Science in Sports and Exercise, 12, 153-158. KIMBALL,J. G . (1981) Normative comparison of the Southern California postrot nystagamus test: Las Angeles vs Syracuse data. American Journal of Occupational z e r o W , 35, 21-25.
888
G . W. GAYLE & R. L. POHLMAN
LINDSEY, D., & O'NEAL,J. (1976) Static and dynamic balance skills of eight year old deaf and hearing children. American Annals of the Deaf, 121, 49-55. LONG,J. (1932) Motor abilities of deaf children. New York: Columbia University, Teachers College Contributions to Education No. 514. MYKLEBUST, H. R. (1946) Significance of etiology in motor performance of deaf children with special reference to meningitis. American Journal of Psychology, 59, 249-258. POTTER,C. N., & SILVERMAN, L. N. (1984) Characteristics of vestibular function and static balance in deaf children. Physical Therapy, 64, 1071-1075. SLOAN,W. (1954) The Lincoln-Oseretsky Motor Development Scale. Lincoln, IL: Lincoln State School. Pp. 25-26. U.S. DEPARTMENT OF EDUCATION. (1988) Tenth annual report to Congress. Washington, DC: Author. VANCE,P C. (1968) Motor characteristics of deaf children. Dissertation Abstracts International, 29, 1145-1146A. WIEGERSMA, P H., & VANDER VELDE,A. (1983) Motor development of deaf children. Jor~rnal of Child Psychology and Psychiatry, 24, 103-111. WINNICK,J. P, & SHORT,F. X. (1986) Physical fitness of adolescents with au&tory irnpairments. Adapted Physical Activity Quarterly, 3, 58-66. WORCHEL, P., & DALLENBACH, K. M. (1950) Vestibular sensitivity in the deaf. American Journal of Psychology, 63, 161-175.
Accepted April 10, 1990.
