Motor Performance Characteristics
The following section examines findings from historical studies with more contemporary research. The implementation of PL 94-142 and subsequent renewal legislation has provided benefits for Deaf children and youth in the area of physical fitness and motor ability. The laws have required the school educational team to examine the type of physical education program provided. As greater numbers of Deaf students were integrated with their H peers, many encountered the same physical education experiences. Perhaps more important, this law has benefited Deaf children and youth with required physical education, assessment, and individual educational planning.
Some differences observed between hearing and Deaf children in research studies may have been due to a lack of appropriate physical activity opportunities for Deaf children. With broader experiences and developmental physical education, differences that have been noted by researchers may not be as apparent. Dummer et al. (1996) noted that delayed motor development may often be caused by environmental factors rather than specific physiological factors associated with deafness. This is reinforced by Butterfield et al. (1993) who noted that school type, curricular emphasis, parenting styles, opportunities for practice, and play critically affect motor development.
Static and Dynamic Balance
Assessment techniques used in the historical studies to determine static (stationary) balance ability included one-leg standing, heel-to-toe standing, and balance beam (or stick) standing. Dynamic (moving) balance assessment included squatting, hopping, jumping over rope, kicking, circle leaping, balance beam (or rail) walking, and balanciometer (or stabilometer). The majority of the studies found deficiencies in both static and dynamic balance for the HI and Df subjects as a group when compared to the H community. There were some exceptions. Vance (1968) found no significant difference between Df and H girls on one-foot balance tasks, and Logan (1969) reported no significant difference on three balance skills for 18-20-year olds; standing heel to toe, crosswise stick standing, and circle leaping. Lindsey and O'Neal (1976) and Gayle (1977) found no significant difference between H and HI subjects in left-leg static balance. In addition, Boyd (1965) reported no difference in the locomotor ability (dynamic balance) of 8-year-old Df and H boys. Lindsey and O'Neal also found no difference between 8-year-old H and Df children in balance beam forward walking, squatting, kicking, and rope jumping.
Inner ear mechanisms, the semicircular canals and vestibule, influence dynamic and static equilibrium, respectively. Some deafness etiologies can damage these organs. However, there were few historical studies, with the exception of Myklebust (1964), establishing specific etiologies as being responsible for damaging these organs and causing balance difficulties. In an analysis of balance in historical research studies, Goodman and Hopper (1992) indicated that some HI subjects were found deficient in dynamic and static balance when compared to H subjects.
The following components were used to assess motor ability: motor inhibition (steadiness), eye-hand coordination, bilateral coordination, eye-hand reaction time, movement time, visual motor control, dexterity, weight shift, locomotor ambulation, squat thrust, climbing, hopping, jumping, throwing catching, kicking, striking, agility, and a short distance run.
Historically, individuals in research studies have been classified into three major groups: HI, Df, and H. Overall, results comparing HI, Df, and H subjects in motor performance were not conclusive. One study indicated that HI and Df subjects were deficient in a skill, while another study may have found them comparable or superior to their H counterparts. An example of this contradiction is revealed in the Campbell (1983) and Bressett (1971) studies which found that H subjects outperformed HI and Df subjects in agility, yet Pender and Patterson (1982) reported that Df subjects excelled in this ability. It is possible that differences were due to variation in recruitment of subjects, test selection, and test administration rather than true differences. Stewart, Dummer, and Haubenstricker (1990) indicated that test administration weaknesses have traditionally existed in physical education research on Df and HI persons.
Dummer, Haubenstricker, and Stewart (1996) found slight differences in the rate of development of fundamental motor skills in children who were deaf compared to hearing children. The mean scores on the Test of Gross Motor Development for 4-year-old children who were deaf were higher than the scores for same-aged children who could hear on both object-control and locomotor skills. The scores for children aged 5 to 10 years who were deaf were lower than the scores for children of the same age who could hear. The differences were relatively small. Overall results indicated that the age patterns of skill acquisition in children who were deaf are very similar to those described for hearing children.
Physical and Motor Fitness
The following components were used in the studies to determine physical and motor fitness: body composition, cardiorespiratory fitness (running speed, maximal breathing, and volume capacity), grip strength, upper-body strength, abdominal strength, leg strength, and flexibility. Studies produced contradictory findings including results indicating that HI and Df children and youth are shorter, lighter in weight, and having more body fat compared to H children and youth. MacMillan and Bruner (1906) found Df boys and girls to be shorter and the girls considerably heavier than their H counterparts. Shephard et al. (1987) concluded that HI males and females had more-than-desirable amounts of body fat. Winnick and Short (1986) found that HI and Df females (but not the males) had significantly larger skinfold measurements than their H counterparts. Vance (1968) found that Df boys were slightly more than 1 inch shorter than their H counterparts and some were 6-1/2 lbs lighter in weight. Shephard et al. (1987) also found the Df subjects to be shorter than the national average.
The historical research studies indicated many equivalencies in physical fitness categories, but also found that Df and HI children did not perform as well as H children overall. MacMillan and Bruner (1906) found Df children to be markedly inferior to H children in lung capacity (forced expiration). Bressett (1971) and Campbell (1983) reported that H subjects were superior to HI and Df subjects in cardiorespiratory endurance, running speed, and leg strength. However, Pender and Patterson (1982) concluded that Df subjects were superior in cardiorespiratory endurance and running speed. Only about a third of Df boys and girls were able to achieve plateau and maximal oxygen uptake in the Shephard et al. (1987) study, and their physical work capacity was below that of their peers. Vance (1968) showed both male and female Df groups to be statistically inferior in grip strength compared to the H group.
Ellis, Butterfield, and Lehnhard (2000) compared the grip strength of children, ages 6 to 19 years, from a residential school for the deaf to a matched sample of hearing children from public schools and found no significant differences. Campbell (1983) found that H subjects outperformed HI and Df subjects in overall sit-up performance; however, Pender and Patterson found no significant difference on this item. Hattin, Fraser, Ward, and Shepard (1986) speculated that the deficit in fitness scores was caused by a lack of motivation.
Ellis, Lieberman, Fittipauldi-Wert, and Dummer (2005) found that deaf children (ages 6 to 11) have at least minimally acceptable levels of fitness. Comparing scores of 151 Deaf children (97 males and 54 females) to the Health Fitness Zone (HFZ) standards used in Fitnessgram, rather than to hearing children, the average number of tests within the HFZ was 4.91 out of 6 tests. High percent body fat was identified as a factor preventing children from succeeding in achieving fitness standards. Results from this study indicated similar age-related trends in fitness found within the literature for hearing children. Dair, Ellis, and Lieberman (2006) found that the prevalence of overweight Deaf children aged 6-11 was above the national percentage for same age and gender. A larger percentage of boys were overweight than girls.
Levels of Hearing Loss
Very few studies attempted to compare the psychomotor performance of children and youth with varying levels of hearing loss. Carlson (1972) assessed 48 students of the Kansas School for the Deaf using the Brace Motor Ability Test (Brace, 1927) and found no significant difference between subjects, who had been divided into three groups according to H level. Burbank (1936) found no significant correlation between hearing ability and balance ability. Butterfield (1987) found that those subjects with the greatest hearing loss performed kicking at a more mature level and that hearing level was not related to jumping, catching, and throwing performance. In the Campbell (1983) study, HI subjects balanced longer and outperformed Df subjects in sit-ups, standing broad jump, 30-foot shuttle run, 30-yard run, and 9-minute run. Winnick and Short (1986) indicated no significant difference between the physical fitness levels of the HI and Df subjects. Overall, there is no compelling evidence of substantial motor performance differences across levels of hearing loss.
Etiology concerns the origin of a disability, but some researchers have attached this term to time-based classifications such as acquired or prelingual hearing loss. Sometimes the cause of the deafness adversely affects the brain or other physical attributes. According to a 1983 survey, approximately 30% of the "educationally significantly handicapped" HI schoolchildren had additional disabilities (Schildroth & Karchmer, 1986). This led some researchers to further qualify HI and Df subjects as physically and mentally "healthy" to indicate no disability other than the hearing loss. In more recent years, Schildroth and Hotto (1994) estimated that 25 percent of students (ages 6 to 21) who are deaf and hard of hearing have one additional disability and 9 percent have two or more other disabilities. Attention Deficit Hyperactivity Disorder is one of the most frequent and pressing secondary disabilities requiring evaluation and services (Parasnis, Samor, & Berent, 2001).
The effect of etiology on motor performance has yet to be established and needs further investigation. Few studies have addressed this issue in a systematic manner. Boyd (1965) and Butterfield (1987) found few statistical differences with etiological groups in terms of motor performance. In the Boyd study, the prenatal (exogenous) group performed poorest overall. Butterfield (1987) found that the genetic etiology group was significantly superior to the idiopathic group in static balance. Brace (1936) reported that the congenital-total deafness group performed more effectively than the acquired total-deafness group in balance. Burbank (1936) determined that the congenital Df group balanced longer than either the unknown or acquired etiology groups, and that the meningitic Df group had poorer balance compared to other etiologies.
Myklebust (1964) reported the meningitic group to be inferior to all other etiological groups in dynamic balance, and Geddes (1978) reported that subjects with a meningitis etiology had balance deficits. Overall, those subjects with congenital etiologies showed superior performance in balance compared to subjects with acquired etiologies. In the acquired category, subjects with a meningitis etiology performed least well as a group.
Until the 1970s, there was a consensus that Deaf individuals had inferior cognitive development. More recent research by Braden (1994) found a nearly identical IQ distribution between deaf and hearing individuals. The Deaf learner has the same cognitive capability as the hearing learner; however, the development of the Deaf child is influenced by linguistic and experiential factors that often impede cognitive development (Shirmer, 2001).
A few historical studies made reference to the intelligence levels of subjects. Today, many of the terms used in these studies are considered unacceptable labels and methodological problems are apparent. In the Morsh (1936) study, the subjects with intelligence test scores of over 100 were classified as "bright," and those with scores of less than 100 were termed as "dull." Eighty-one Df and 99 H subjects were classified as bright while 58 Df and 64 H subjects were classified as dull. However, this classification was made from a variety of intelligence tests. There was no difference in balance ability of Df subjects according to intelligence, in contrast with the H subjects, in which the bright group subjects were superior. The subjects in the Boyd (1965) study all had IQs ranging from 94 to 106, while those in the Vance (1968) study had IQs ranging from 90 to 115. The subjects in the Lindsey and O'Neal (1976) study had IQs ranging from 80 to 130. It is unclear what effect, if any, intelligence has on motor performance. Overall, the communication skills of Deaf individuals are influenced by limited reading and writing skills. In many cases these skills are at a fifth-grade level (Sherill, 2004).