MOTOR AND VISUOMOTOR SKILLS OF CHILDREN ...

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tests), but none for fine motor vs gross motor skills (using a dependent sample t test). Significant positive correlations were found for gross motor skills with ...
Perceptual and Motor Sktll.\, 2007, 104, 1183-1192. O Perceptual and Motor Skills 2007

MOTOR AND VISUOMOTOR SKILLS O F CHILDREN WITH ASPERGER'S DISORDER: PRELIMINARY FINDINGS ' CHRISTOPHER LOPATA

ELLEN M. HAMM

Department of Counseling, School and Educational Psychology University at Buffalo, State Univenity of New York

Canisius College

MARTIN A. VOLKER

JILL E. SOWINSKI

Department of Counseling, School and Educational Psychology University at Buffalo, State University of New York

University at Buffalo, State Universty of New York

MARCUS L. THOMEER

Summit Educational Resources Summay.-While motor clumsiness is frequently described as an associated feature of Asperger's Disorder, little research has examined specific motor skills and the relation among aspects of motor performance in this population. The present purpose was to present preliminary findings for three aspects of Asperger's: the presence and magnitude of gross motor and fine motor deficits, the presence and magnitude of visuomotor deficits, and the relation between motor functioning and visuomotor skills. 17 boys, 6 to 13 years old, with Asperger's were tested using standardized measures of gross, fine, and visuomotor skills. Statistically significant deficits were found for the sample's scores compared with values for the general population (using one-sample t tests), but none for fine motor vs gross motor skills (using a dependent sample t test). Significant positive correlations were found for gross motor skills with visuomotor skills (.73) and for fine motor slalls with visuomotor skills (.71). Tcntative suggestions for clinical assessment were proposed.

Asperger's Disorder is a neurological disorder grouped under the broad diagnostic category of Pervasive Developmental Disorders, also sometimes referred to as Autism Spectrum Disorders (Gillberg, 2002). Key diagnostic features of the disorder include significant qualitative deficits in social interaction and narrow and stereotyped patterns of interests and behaviors (American Psychiatric Association, 2000). Motor clumsiness has also been associated with the disorder (Ghaziuddin & Butler, 1998; Miller & Ozonoff, 2000). In fact, in an early operational definition of Asperger's disorder, Gillberg and Gillberg (1989) included motor clumsiness as one of six primary areas of impairment necessary for diagnosis. Weimer, Schatz, Lincoln, Ballantyne and Trauner (2001) stated Bonnet and Gao in 1996 reported an esti'Address corres ondence to Dr. Christopher Lopata, 409 Baldy Hall, University at Buffalo SUNY, Buffalo, 14260-1000 or e-mail ([email protected]).

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DO1 10.2466/PMS.104.4.1183-1192

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mate of 80% of individuals with the disorder show some form of clumsiness. Although not included in the diagnostic criteria of the International Classification of Diseases, Tenth Edition (World Health Organization, 1993) or the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (American Psychiatric Association, 2000), both classification systems note that motor clumsiness is frequently observed in individuals diagnosed with Asperger's. Despite recognition of motor clumsiness as an associated feature of Asperger's, the characteristics of the impairment remain poorly understood. One reason is a lack of consensus regarding what constitutes clumsiness. According to Smith (2OOO), it is often unclear whether the term clumsiness refers to gross or fine motor skills or a combination. Additionally unclear are the types of tasks appropriate to assess clumsiness. Prior researchers have presented a wide range of procedures such as caregivers' reports and normreferenced tests (Smith, 2000). Despite the difficulties, motor and perceptual-motor skills have been suggested as important in understanding clumsiness in these children (Smith, 2000).

Motor Skills and Asperger's Gillberg (1992) stated a frequently noted physical feature of children with Asperger's is motor clumsiness. According to Gillberg and Coleman (1992), motor deficits can be indicated by poor performance on neurodevelopmental examinations as well as awkward, uncoordinated motor movements. The impairment can also appear in one or more areas of motor performance such as fine and gross motor skills and visuomotor skills. Fine motor control requires awareness and planning for execution of a task, muscle strength, coordination, and motor sensation (Gepner & Mestre, 2002), while gross motor control requires the integration of muscular, skeletal, and neurological functions to produce large general movements. If gross motor control is impaired, fine motor movements are usually also. Tasks which require complimentary movements of body parts have been noted to be performed in an awkward, stiff, and ill coordinated manner by children with Asperger's (Gillberg, 2002). Although Asperger's has distinct diagnostic criteria, debate is considerable as to whether it can be distinguished from other autism spectrum disorders; for a comprehensive discussion of diagnostic issues, see Volkmar and Klin (2000). One area, suggested as potentially useful in distinguishing the diagnostic categories is the motor domain (Smith, 2000). Despite this suggestion, research has not supported motor abilities as a feature which reliably distinguishes Asperger's from other autism spectrum disorders. This research has, however, provided some information related to motor impairments with Asperger's.

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Several studies have compared motor performance of children with differing autism spectrum disorders, but, because these studies were directed at diagnostic group comparisons, the motor skills of children with Asperger's were not closely examined. For example, Manjiviona and Prior (1995) compared the motor performance of I2 children with Asperger's with that of nine children with high functioning autism. Their average age was I 1 yr., and all were of normal or near normal intellectual ability. The study examined manual dexterity, ball skills, and static and dynamic balance using the Test of Motor Impairment-Henderson Revision (Stott, Moyes, & Henderson, 1984). Analysis of scores indicated no group differences in motor impairment; however, both groups showed motor problems compared to test norms. Specifically, 50% of those with Asperger's and 67% of those with high functioning autism showed significant motor impairment (Manjiviona & Prior, 1995). In another study Ghaziuddin and Butler (1998) examined motor clumsiness of I2 children with Asperger's compared to age- and sex-matched children with autism ( n = 12) and Pervasive Developmental Disorder-Not Otherwise Specified (n = 12). Intelligence scores varied for the groups, with the Asperger's group having higher IQ scores (M= 105) than the other two groups (M=78). The Bruininks-Oseretsky Test of Motor Proficiency (Bruininks, 1978) was used to assess fine motor and gross motor skills and provided an overall measure of motor skills. Once I Q differences were taken into account, no significant differences were found in the mean coordination test scores of the three groups, but all three groups showed significant motor skills deficits (Ghaziuddin & Butler, 1998). Although such results suggest the presence of motor deficits, the studies did not examine motor skills specifically in children with Asperger's. And, while these studies provided overall scores for fine and gross motor performance, there was little discussion of subtest performance. Further research is necessary to clarify the extent to which fine and gross motor skills are impaired (Ghaziuddin & Butler, 1998; Smith, 2000).

Visuomotor Skills and Asperger's Another explanation for motor clumsiness in children with Asperger's involves possible underlying visuomotor difficulties. While the previous studies have presented some evidence of motor impairment, studies of Asperger's and other autism spectrum disorders have not systematically included measures of visuomotor integration. A study conducted by Weimer, et al. (2001) examined numerous facets of motor performance with a range of measures including a test of visuomotor integration for 10 boys with Asperger's (M= 15.7 yr.) and I0 nondisabled boys (M= 15.9 yr.). Participants were matched on age, sex, socioeconomic status, and Verbal IQ. Analysis showed

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no significant group difference on visuomotor scores on the Developmental Test of Visual-Motor Integration, Third Edition (Beery, 1989). Although not discussed further by the researchers, the mean visuomotor standard score of M =90.1 for those with Asperger's was approximately two-thirds of 1 standard deviation below the normative mean, which suggests an effect large enough to merit closer attention. Another study examined perceptual-motor deficiency in children with autism. Fulkerson and Freemen (1980) used the visuomotor performance of 15 children with autism and 30 matched controls (15 who completed the same tasks as the children with autism, and 15 who completed one visuomotor task several times) to examine different hypotheses about the origin of perceptual-motor difficulties. Participants were matched for initial performance scores on the Developmental Test of Visual-Motor Integration (Beery, 19641, so resulting groups differed in average age. Specifically, the group with autism was an average of 3 yr. older than the control group. Participants were then tested on a modified Visual-Motor Integration task that involved tracing a stimulus before taking the test again and watching an examiner demonstrate the copying before performing the test again. The children were also tested on copying test stimulus figures on paper which contained background interference, on figure-ground tasks, and on a test of motor accuracy which required tracing a shape within the boundaries of a printed path. Analysis indicated the children with autism performed significantly more poorly on the motor-tracing task and when background interference was introduced. Researchers claimed that these results supported hypotheses that perceptual-motor deficits in children with autism are related to problems in motor coordination and visuomotor monitoring. While several studies have provided some preliminary evidence of motor deficits in children with Asperger's, closer examination is needed (Ghaziuddin & Butler, 1998). Prior studies included small samples and have not examined the relationship between motor and visuomotor skills. In the present study, four specific hypotheses were tested using a relatively larger sample. It was hypothesized that (1) boys with Asperger's would have significantly lower fine motor and gross motor skills than the population estimates on the Bruininks-Oseretsky Test of Motor Proficiency (Bruininks, 1978); (2) there would be no significant difference between fine motor and gross motor skills for the sample with Asperger's; (3) boys with Asperger's would have significantly lower visuomotor skills than the population estimates on the BeeryBuktenica Developmental Test of Visual-Motor Integration (Beery & Beery, 2004); and (4) there would be a significant correlation between fine motor and visuomotor skills, as well as between gross motor and visuomotor skills.

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Participants The sample of 17 boys were 6 to 13 yr. of age (M= 10.1, SD=2.0), diagnosed with Asperger's and enrolled in a summer social skills treatment program. Each child participated in a three-phase process to evaluate the accuracy of the diagnosis. In the first phase, parents submitted a formal written diagnosis of Asperger's from a licensed psychiatrist or psychologist with relevant assessment reports and documents (e.g., psychiatric and psychological evaluations, IEP, etc.). Parents also completed an intake packet describing their child's developmental and social history and demographic characteristics. In Phase 2, two members of the senior research team independently reviewed each child's developmental history and reports to evaluate whether the data met diagnostic criteria for Asperger's delineated in the DSM-IV-TR (American Psychiatric Association, 2000). Their agreement was required to move the child to Phase 3, in which participants completed additional standardized assessments (e.g., I Q testing and tests of adaptive skills and behavior). Children without a significant cognitive deficit and developmental language delay were accepted into the summer treatment program. A total of 34 case files were reviewed at Phase 2 and 21 (61.8%) were rated by both senior researchers as meeting the criteria for Asperger's. Subsequent testing in Phase 3 supported the diagnosis of Asperger's for these 21 who were accepted into the summer social skills program. From these 21 boys 4 were excluded from the current study (approximately 19%) given comorbid neurological disorders. IQ testing during Phase 3 used the Wechsler Intelligence Scale for Children, Fourth Edition (Wechsler, 2003). The average I Q for the 17 boys fell in the average range (i.e., M=98.7, SD= 16.3), and all were from middle to upper income households. The Bruininks-Oseretsky Test of Motor Proficiency (Bruininks, 1978) was used to assess gross motor control, fine motor control, and coordination, as it has been used in motor research with autism spectrum disorders (e.g., Ghaziuddin & Butler, 1998), and is commonly used in clinical practice. Gross motor control was measured on four subtests including running speed and agility, balance, bilateral coordination, and strength. Fine motor skills were measured using three subtests of response speed, visuomotor control, and upper-limb speed and dexterity. Coordination was measured on a subtest which specifically assessed upper limb coordination. As reported in the test manual, test-retest reliabilities for gross motor and fine motor composites were .81 and 3 0 , respectively. Interrater reliabilities were reported for the Visual-Motor Control subtest only. Median correlations for two groups of raters were .90 and .98. Evidence of validity was described in terms of association of test scores with chronological age, i.e., scores increased with age

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(Mdn r = .78). Validity was also based on discrimination of test scores for typical children and those with disabilities, such as mild mental retardation, moderate-to-severe retardation, or learning disabilities. The normal children scored significantly higher than each of the other three groups (Bruininks, 1978). Visuomotor skills were measured using the Beery-Buktenica Developmental Test of Visual-Motor Integration (Beery & Beery, 2004), a standardized measure for identifying difficulties in integrating visuoperceptual and motor abilities. Visual-motor integration was defined as "the degree to which visual perception and finger-hand movements are well coordinated" (Beery & Beery, 2004, p. 12). The test requires children to reproduce 24 geometric figures arranged in order of increasing difficulty. Split-half correlations ranged between .82 and .90, and coefficients alpha between .79 and .85 for the 6 to 13-yr.-old age group. Overall, interscorer reliability was reportedly .92. Support for concurrent validity was presented as correlations with test scores for similar constructs. Low to moderate values were reported with similar tests including the Developmental Test of Visual Perception-2 (.75) and the Drawing subtest of the Wide Range Assessment of Visual Motor Abilities (.52) (Beery & Beery, 2004). Procedure Motor and visuomotor testing was completed by a licensed occupational therapist with the assistance of a graduate student. All participants were involved in a 6-wk. summer social skills treatment program, without motor skills intervention. During the fourth week of the summer treatment program, participants were administered Beery's test in a group, using standard procedures. The Bruininks-Oseretsky Test of Motor Proficiency was also administered individually during this week using standard procedures. All testing was conducted during the day, and upon completion participants returned to the programmed activities. To increase scoring accuracy, each protocol in the study was scored twice, and if a discrepancy occurred a third assessor scored the protocol. Fine and Gross Motor Skills Means and standard deviations for the Bruininks-Oseretsky Test of Motor Proficiency are presented in Table 1. The mean composite scores for gross and fine motor skills are based on T-score distribution of M = 5 0 and SD= 10 (Bruininks, 1978). Descriptively, the sample's mean composite scores for gross motor skills (30.4) and fine motor skills (29.4) were approximately 2 SDs below the population mean and considered low according to the test manual. Mean subtest scores are also reported in Table 1.

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TABLE 1 DEVIATIONS FORBRUININKS-OSERETSKY TESTOF MOTORPROFICIENCY MEANSAND STANDARD AND BEERY VISUAL-MOTOR INTEGRATION-V (VMI-V) STANDARD SCORES(N= 17)

-

-

Test, Domain, and Subtest -

Bruininks-Oseretsky - Beery VMI-V

M

Bruininks-Oseretsky Test of Motor Proficiency 50" Gross Motor Composite 30.4 Running Speed and Agility Balance Bilateral Coordination Strength Fine Motor Composite 29.4 Response Speed Visual-motor Control Upper-limb Speed and Desterity Beery Visual-Motor Integration-V 100" Test Composite 83 "Normative mean and standard deviation for each test.

SD

M

SD

10 14.9

15

5

5.2 8.2 10.1 6.4

6.0 8.1 5.8 6.9

4.1 8.2 9.0

3.8 7.4 6.2

-

11.5

15 18.5

-

To assess whether the current sample differed significantly from the general population, a one sample t test was applied separately for the gross and fine motor composites. To control for experiment-wise error and reduce the probability of Type I error, a Bonferroni correction was applied to all tests of significance. Based on the four statistical comparisons across gross, fine, and visuomotor scores, the adjusted alpha level was set at .0125. The one-sample t tests were significantly different for the gross motor composite of the sample and the population mean (t,, = -5.44, p < ,001, d = - 1.97) and for the fine motor composite for the sample and the population mean (t,, = -7.37, p < .001, d = -2.06). Specifically, the current sample scored significantly lower in gross and fine motor skills than the normative general population. The standardized effect size estimates (i.e., Cohen d ) were consistent with a large effect (Cohen, 1988). Gross motor and fine motor skills were also compared by area using a dependent-samples t test, but composite scores were not significantly different (t,, = 3 7 , p = .72, d = 0.07). The effect size d estimate indicated the obtained difference was negligible. Visuornotor Skills The mean and standard deviation for the Beery Visual-Motor Integration Test-Fifth Edition are presented in Table l . This test has a normative mean of 100 and a standard deviation of 15 (Beery & Beery, 2004). The mean standard score for the current sample was 83 (i.e., more than 1 SD below the normative population mean), which differed significantly from the general population on a one-sample t test (t,, = -3.79, p < .005, d = - 1.13),

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with the current sample scoring significantly lower. According to Cohen standards (1988), the effect size d was large.

Relation of Visuomotor Skills to Gross and Fine Motor Skills Finally, bivariate correlations were conducted for the gross motor composite score with visuomotor skills and also for the fine motor composite with visuomotor skills. The statistically significant r,, of .73 ( p < .005), and .71 ( p < .005), respectively, were strong. D~scussro~ This paper presented some preliminary findings on presence and magnitude of gross motor, fine motor, and visuomotor deficits in a sample of 6 to 13-yr.-old boys with Asperger's, to test the hypotheses that the boys would show significant deficits in gross, fine, and visual motor skills, but none between gross and fine motor skills, and there would be a significant correlation between visuomotor skills and fine motor skills and gross motor skills. All hypotheses were supported and the significant deficits appeared consistent with previous reports of awkward and uncoordinated movements and poor performance on neurodevelopmental and motor-based tasks (Gillberg, 1992; Ghaziuddin & Butler, 1998; Gepner & Mestre, 2002). The lack of significant difference between scores for fine and gross motor skills is consistent with Ghaziuddin and Butler (1998), who reported a high correlation between the fine and gross motor sections of the Bruininks-Oseretsky and also of the claim by Gepner and Mestre (2002) that if gross motor skills are impaired, there will most likely be similar impairment in fine motor control. Performance on the motor subtests suggested some specific areas were more problematic for participants. Among the gross motor subtests, participants scored lowest on running speed and agility, and strength. Running speed scores fell nearly 2 SDs below the mean, while performance was poor on the Bruininks-Oseretsky which tests strength by sit-ups and push-ups, both of which require motor planning for executing the proper body position. Few boys performed more than one push up, and those who could did so with extreme difficulty. Examination of fine motor subtest performance reflected poor performance on response speed which measures response to a moving stimulus. Specifically, a child places a hand flat on the wall next to a vertical stick held by the examiner. The examiner releases the stick, and the child stops the stick against the wall with his thumb as quickly as he can, a task which requires motor planning. All boys scored below the normative mean. According to Dawson and Watling (2000), visuomotor integration skills and spatial orientation are necessary for the accurate development of motor skills. This group of boys scored significantly below age norms for the general population, which is somewhat contrary to work by Weimer, et al.

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(2001), who reported no significant difference between their group with Asperger's and matched controls, despite the general performance for the Asperger's group being approximately 2/3 of a standard deviation below the population mean. However, Weimer, et al.'s participants were generally older than the present boys. Whether an age difference might explain these results requires further study. For current participants, duplication of dimensional shapes seemed to pose the greatest challenge. While overall visuomotor skills appeared somewhat more intact than gross and fine motor skills. visuomotor performance was significantly below age norms. Although preliminary, these results provide information about the motor problems of children with Asperger's and the quantification of the term clumsiness (Klin, Volkmar, & Sparrow, 2000). Further, data are yet sparse for guidance in assessment and treatment (Klin & Volkmar, 2000). It may be wise for clinicians to conduct a comprehensive assessment including gross, fine, and visuomotor skills when evaluating children with or suspected of having Asperger's. Careful attention to potential limitations of chosen measures for their sensitivity to lower skills is necessary as this would limit evaluation of this population's motor and visuomotor skills. For example, the high percentage of present boys who achieved the lowest possible standard score on the fine and gross motor composites of the Bruininks-Oseretsky suggests this test shows floor effects, i.e., lack of sensitivity to poor performance. Since children with Asperger's are likely to show deficits in many areas of motor performance, these preliminary findings cannot be more specific. Whatever interventions are used, recommendations for this population are quite tentative since research is too sparse (Dawson & Watling, 2000; Goldstein, 2000). Attention is directed to the present small sample, which was larger than those tested in earlier work but are so small as to limit generalizability. In addition, the measures administered do not assess relevant aspects of motor behaviors. Given these limitations and the preliminary findings, a much larger sample which includes age- and sex-matched children without disabilities is required for generalizability. REFERENCES AMERICAN PSYCHIATRIC ASSOCIATION. (2000) Diagnostic and statistical manual of mental di.sorders. (4th ed., Rev.) Washington, DC: Author. BEERY,K. E. (1964) Geometric form reproduction: developmental studitts of visual-motor integrity. Chicago, IL: Follett. BEERY,K. E. (1989) The VMI: Developmental Test of Visual-Motor Integration. (3rd ed) Cleveland, O H : Modern Curriculum Press. BE~RY, K. E., &BEERY,N. A. (2004) The Beery-Buktenica Developmental Test of Visual-Motor Integration. (5th ed.) Minneapolis, MN: Pearson Learning. BONNET,K. A., & GAO,X. K. (1996) Asperger syndrome in neurologic perspective. journal of Child Neurology, 11, 483-489.

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Accepted April 17, 2007