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Neuropsychological skills with motor dysfunctional and motor normal children
Adives of Clinical Neuropsjdology, W. Printed in the USA. All rights resemcd.
6, pp. 271-278,
1991 Copyright
oaa7-6177/91$3.00+ .oo 0 1991 National Academy of Neuropsychology
Neuropsychological
Skills With
Motor
and Motor
Dysfunctional
Normal Children Jeffrey H. Snow New Medico Rehabilitation
Center, Timber Ridge Ranch
Thomas A. Blondis University of Missouri School of Medicine
Richard A. English University of Missouri-Columbia
A group of 40 children was selected from a larger sample based on their performance on motor coordination, motor speed, and motor inhibition tasks. Twenty of Ihe children were classified as Motor Dysfunctional (MD) and 20 were classified as Motor Normal (MN). The groups were compared on several neuropsychological measures. The results indicated Ihe MD children were significantly lower on a number of measures, particularly those requiring sensory integration. There were not sign$cant dif/erences on several of Ihe tasks, including those more complex in nature. The results are discussed in relation to developmenral models of neuropsychological functioning.
The examination of motor skills is an integral part of any neuropsychological assessment conducted with children (see Gaddes, 1985 and Rourke, Bakker, Fisk, & Strang, 1983). Testing and analysis has proven beneficial in understanding of the motor “clumsy” child (Bax & Whitmore, 1987; Lord & Hume, 1987). Lord and Hume found that children who were motor clumsy performed This project was supported in part by a grant from the Center for Educational Assessment, University of Missouri-Columbia College of Education. Requests for reprints should be sent to Jeffrey H. Snow, New Medico Rehabilitation Center, Tiiber Ridge Ranch, PO. Box 90, Benton, AR 72015. 271
272
J. H. Snow, T. A. Blondis, and R. A. English
significantly poorer than normal children on motor tasks. Additionally, they found that the clumsy children were also significantly lower on measures of visual-spatial processing which led the authors to conclude that poor visual processing may be related to poor motor performance. Bax and Whitmore found that motor clumsy children were significantly more at-risk for learning problems than were children with normal motor skills. The importance of incorporation of motor assessments is supported from a clinical perspective. For example, Bawden, Knights, and Winogran (1985) examined speeded and nonspeeded performance with head-injured children. These authors found that speeded performance (which was largely assessed using tasks which required a motor response) was significantly more impaired for the severely head-injured children as opposed to the mildly and moderately head-injured children. Snow, Blondis, and Brady (1988) found motor speed and motor coordination tasks to contribute significantly to the discrimination of academically at-risk children from normal children. The intent of the present study was to examine the neuropsychological performance of children who evidence motor difficulties as compared with children who had normal motor functioning. Children with dysfunctional motor skills were selected and normal controls were matched to this group. Followup comparisons were completed with other neuropsychological measures. The purpose of this study was to provide more comprehensive data concerning neuropsychological profiles of motor dysfunctional children.
METHOD Subjects The subjects for this study consisted of 40 children between the ages of 6 and 11 years. The children were selected from randomly generated lists of students enrolled in regular education. The mean age in months for the entire sample was 107.28 with a standard deviation of 20.65. There were 22 males and 18 females. In terms of racial composition, all of the children were white. Twenty of the children were classified as Motor Dysfunctional (MD) and 20 were classified as Motor Normal (MN). Each of these groups consisted of 11 males and 9 females. The children were randomly selected from four Missouri school districts. Measures Motor Coordination. Derived from Shafer et al. (1986) this task consisted of repetitive hand pronation-supination. This was scored for periodicity (uniformity of movement) for each hand, alternation for each hand, and precision in hitting a target for each hand.
273 Associated Movements. Also derived from Shafer et al. (1986), mirror movements were examined for each child as an index of motor overflow. The child opposed each finger of his or her hand to his or her thumb in succession. The nonperforming hand was observed for degree of movement during the task. This task was scored for amount (i.e, distance} of movement with the nonperforming hand and frequency of movement with the non~rfo~ing hand. Motor Speed. Also derived from Shafer et al. (1986), this measure consisted of
timed performances on the hand pronation-supination and successive finger touching tasks. In addition, timed performances were also obtained on a heel-toe alternation task. Tactile Integration. Graphasthesia was used to assess tactile integration skills for both the right and the left hands. The child was shown a sheet that had three figures (triangle, square, circle), three numbers (3,5, 8), and three letters (II, F, P). Following correct recognition of the stimuli, he or she then closed his or her eyes and all nine of the forms were drawn on the back of each hand. Auditory Memory. A modified version of the Memory for Sentences subtest from the Woodcock-Johnson Psychoeducational Battery (Woodcock & Johnson, 1977) was used to assess short-term auditory memory. The task consisted of 20 sentences, with the length and complexity of each sentence gradually increasing. Visual-Spatial Analysis. Mental rotation was used to assess visual-spatial manipulation skills. The task was adapted from Thurstone (1968). Cards were presented to the subjects with an upright stimulus at the top and three rotated stimuli below. Two of the stimuli below were mirror images and the third was the correct response. A total of 28 stimulus cards were scored with 12 consisting of letters, 8 consisting of objects, and 8 consisting of figures. ~s~l Mutching. A timed matching task was used to assess visual integration skills. This task was a modified version of The Underlining Test (Rourke & Gates, 1980). For this task, the child was presented separate sheets of paper with one-, two-, and three-letter combinations at the top. The child was instructed to find al1 of the letter patterns which matched the stimulus and to circle them. The child was given 60 seconds for each sheet. Cruss-se~s~~ ~~tegr~f~~~. Dichaptic matching derived from Witelson (1974, 1976) was used to assess cross-modal integration. The task utilized 12 wooden blocks. The blocks were four- and eight-point nonsense shapes randomly selected from Vanderplas and Garvin’s (1959) associative values for random shapes. All of the shapes were drawn on a card for subject responding. Each child was instructed to close his or her eyes. A different shape was placed in each hand and the subject was allowed to manipulate these shapes for five seconds. Following shape presentation, the subjects opened their eyes and pointed to the shapes they recognized feeling. During the pointing phase, the subjects
274
J. H. Snow, T. A. Blondis, and R. A. English
clasped their hands to control for any pointing hand X shape effect. The task consisted of 20 stimulus pair presentations, with the first 10 as practice trials. Auditory Integration. A word blending task adapted from the Woodcock-Johnson (1977) was used to assess auditory integration. Words were broken down into distinct sounds and presented to the subjects with a one-second interval between each sound. The subjects were instructed to listen to the sounds and to identify the word that those sound make. The task consisted of 14 stimulus words with practice-training items. The entire subtest was administered to all of the children. Verbal Output. Word fluency derived from the McCarthy Scales of Children’s Abilities (1972) was used to assess verbal output. The child was instructed to generate as many words as possible in defined categories. The categories were animals, things to eat, and things to ride in. The subjects were given 30 seconds for word generation in each category. Procedure Signed parental permission was obtained for each child prior to testing. Each child was seen on an individual basis and administered the battery by a trained examiner. The order of administration for the different measures was determined randomly prior to data collection and was the same for all of the subjects. The sample for this study was drawn from a larger sample of children. Utilizing the larger sample (N = 169), raw scores were converted to T-scores (M = 50; SD = 10) by age level. Criteria for the MD group were as follows: (i) T-scores above 60 on at least three of the six motor measures (i.e., right- and left-hand motor coordination, right- and left-hand-associated movements, and right- and left-side motor speed); and (ii) no T-scores below 50 on any of the motor measures. Criteria for the MN group were as follows: (i) no T-scores above 60 on any of the motor measures: and (ii) at least three of the six motor T-scores below 50. The MN children were matched to the MD children in terms of sex and age.
RESULTS Table 1 lists the means and standard deviations for the two groups. The MD children were considerably higher on the motor indices which would be expected given that these were the criteria for classification. There was some variability with the other measures, but generally the MD children were more impaired. Factor Analysis Utilizing the larger sample, a factor analysis was conducted. Using Principal Components analysis with an eigenvalue greater than one criteria,
Neuropsychological Skills
275
TABLE 1 Means and Standard Deviations for Both Groups on Each Variable Group MD
M
Variable Motor
Coord. Right Motor Coord. Left
63.65 58.15
Motor Speed Right Motor Speed Left Assoc. Mov. Right Assoc. Mov. Left Graph. Right Graph. Left Memory for Sent. Mental Rotation Visual Discrim. Cross-Modal Right Cross-Modal Left Auditory Blending Word Fluency
60.35 59.60 60.40 56.40 44.15 45.15 46.80 48.90 42.80 45.65 50.15 45.85 48.70
MN SD
M
SD 8.56 11.04 13.88 14.10 10.42 10.33 9.55 9.50 8.42 11.13 7.55 9.17 8.20 11.60 9.76
44.20 42.85 44.00 46.40 49.05 45.65 53.80 54.40 51.40 54.15 55.90 58.55 55.05 53.20 53.70
4.94 4.42 6.97 6.29 1.39 10.87 9.38 7.07 8.45 8.62 9.10 9.24 10.76 6.18 9.27
six factors were retained for rotation. These factors accounted for approximately 67% of the variance. Table 2 lists the rotated factor structure for the battery. Factor 1 had moderate to high loadings from the motor speed and word fluency tasks. Factor 2 appears to reflect integrative visual and crossmodal skills with moderate to high loadings from visual discrimination, mental rotation, and dichaptic matching. Factor 3 had high loadings from the associated movement measures while factor 4 reflects motor coordination.
TABLE 2 Factor Structure for the Test Batterv Factor Variable Motor Coord. Right Motor Coord. Left Motor Speed Right Motor Speed Left Assoc. Mov. Right Assoc. Mov. Left Graph. Right Graph. Left Memory for Sent. Mental Rotation Visual Discrim. Cross-Modal Right Cross-Modal Left Auditory Blending Word Fluency
I
II
III
IV
V
VI
.18 .07 .83 .80 .04 -.09 -.12 .02 -.48 -.14 -.02 -.07 .23 -.08 -.58
-.03 -.15 .Ol .07 .08 .02 .07 .22 -.Ol .58 .43 .73 .78 .16 .06
.07 .07 -.13 -.ll .89 .85 -06 .03 -.09 .12 -04 -.02 .04 .04 -.20
.I6 .80 .20 .22 -.02 .14 -.12 -06 -.05 -.26 -.14 .07 -SK -.03 .40
-. 14 -.05 -.13 -.13 -.03 -00 .86 .80 -.ll -.lO -.18 .15 .ll .08 .03
.02 -.03 -.15 -.16 -.04 .04 -.Ol .06 .50 .07 -.39 .03 08 .82 -.12
276
J. H. Snow, T. A. Blondis, and R. A. English
Factor 5 was a tactile integration factor with high loadings from graphasthesia and factor 6 appears to reflect auditory processing with moderate to high loadings from memory for sentences and word blending. Analysis of Word Fluency Abilities Word fluency loaded on the first factor along with motor speed. The results of the t-test comparison for word fluency approached, but was not statistically significant (t(39) = 1.66, p > .OS). Analysis of Visual Integrative
Functioning
Measures which loaded on the second factor (i.e., mental rotation, visual discrimination, dichaptic matching) were combined and a MANOVA was run. The results indicated a significant difference (Pillai’s Trace F(4,35) = 9.46, p < .OOOl). Examination of univariate ANOVA’s indicated significance for visual discrimination (F(1,38) = 24.54; p < .OOOl) and dichaptic matching with the right hand (F(1,38) 19.63; p < .OOOl). With both measures, the MN group was higher than the MD group. Significance was not reached with mental rotation (F(1,38) = 2.78; p > .05) nor with dichaptic matching with the left hand (F(1,38) = 2.63; p > .05). Analysis of Tactile Integration
Abilities
Scores for graphasthesia right and was conducted. The results indicated F(2,37) = 7.51; p < .OOl). Examination significance for both the right (F(1,38) 10.67; p < .002) hands. The MN group group on both of these measures. Analysis of Auditory tntegralion
left were combined and a MANOVA a significant difference (Pillai’s Trace of the univariate ANOVAs showed = 9.14; p < .004) and left (F(1,38) = was significantly higher than the MD
Skills
The final comparison was made between the groups on the memory for sentences and auditory blending subtests. The MANOVA with these measures reached significance (F(2,27) = 3.70; p < .03). The univariate ANOVAs indicated a significant difference for the auditory blending subtest (F(1,38) = 6.26; p < .Ol) but not for the memory for sentences subtest (F(1,38) 2.97; p > .05). The MN group was higher than the MD group on the blending test.
DISCUSSION In examining the pattern of results, it is apparent that the MD children were significantly more impaired than the MN children with basic sensory integra-
Neuropsychological Skills
277
tion/discrimination. This was evidenced by bilateral depression on the graphasthesia subtest, low performance on the visual matching task, and difficulty with auditory blending. This would suggest dysfunction in base neuropsychological skills beyond those involving motor systems. The bilateral depression with tactile integration skills may, in part, account for difficulties with motor performance. This would be the case particularly with motor speed and motor coordination since these skills are so closely tied with adequate kinesthetic feedback. The MD children were not, however, significantly below the MN children on all of the measures administered. Nonsignificant differences were observed for word fluency, mental rotation, dichaptic matching with the left hand, and memory for sentences. The characteristics of these subtests include little or not reliance on any type of motor response. Task complexity may be another factor influencing observed differences. Developmental neuropsychological theories tend to be hierarchical in nature (See Rourke, 1984; Vygotsky, 1965). With these models it would be predicted that if base functional systems are dysfunctional, then latter developing more complex systems will generally be impaired. With the present study the base sensory-motor systems were clearly dysfunctional for the MD children, yet, as stated above, performance was equivocal for several of the more complex tasks. This finding does not support a hierarchical view of neuropsychological development. An alternative explanation would be dysfunction-functional reorganization. Given the functional system for more complex tasks changes with age, this would suggest there are qualitatively different means to accomplish the same end. In other words, original functional systems may have been impeded by dysfunctional development and then compensated for by altemative systems. This possible explanation is tentative and needs to be investigated further both experimentally and longitudinally. The results of this investigation are somewhat different from those reported in an earlier study (Boll, Berent, & Richards, 1976). These investigators found that normals and brain-damaged children classified on the basis of tactile-perceptual abilities (i.e., good vs. poor) were significantly different on measures of motor speed and higher cognitive functioning. The primary difference between the present study and the Boll et al. investigation relates to the classification variables in that those employed by Boll et al. were more sensitive to generalized cortical functioning. In summary, the present study indicated that MD children did show impaired performance on several neuropsychological measures when compared to MN children. The results point toward a generalized deficit in basic sensory-motor integrative skills, but not necessarily with skills independent of motor functioning. Caution should be exercised when considering these results because of the relatively small sample size employed. Replication with a substantially larger and more diverse sample is certainly warranted. In addition, longitudinal investigations with MD and MN children would shed light on the developmental rela-
278
J. H. Snow, T. A. Blondis, and R. A. English
tionship between higher neuropsychological skills and lower motor functions. The present study indicated the MD children either did not suffer impaired development or had the capacity to use com~nsato~ strategies. Di~erentia~g between these and other explanations would be of both practical and theoretical significance in the area of developmental neuropsychology.
REFERENCES Bawden, H. N., Knights, R. M., & Winogmn, H. W. (198.5). Speeded performance following head injury in children. Journal of Clinical and Experimental Neuropsychology, 7,39-54. Bax, M., & Whitmore, K. (1987). The medical examination of children on entry to school. The results and use of neurodevelopmental assessment. Developmental Medicine and Child Neurology, 29,40-S.
Boll, T. J., Berent, S., & Richards, H. (1976). T~tile-~rceptile f~ctioning as a factor in general psychological abilities. Per~ept~l and Motor Skills, 44,535539. Gaddes, W. H. (1985). Learning disabilities and brain function: A neuropsychological approach (2nd ed.). New York: Springer-Verlag. Lord, R., & Hume, C. (1987). Perceptual judgments of normal and clumsy children. Developmental Medicine and Child Neurology, 29,250-251. McCarthy, D. (1972). McCarthy scales of children’s abilities. New York: The Psychological Co~ration. Rourke, B. P (1982). Central processing deficiencies in children: Toward a development neuropsychological model. Journal of Clinical Neuropsychology, 4, 1-18. Rourke, B. P., Bakker, D. J., Fisk, J. L., & Strang, J. D. (1983). Child neuropsychology: An introduction to theory, research, and clinical practice. New York: Guilford. Rourke, B. P., & Gates, R. D. (1980). The underlining test. Windsor, Ontario: University of Windsor. Shafer, S. Q.. Stokman, C. J.. Shaffer, D., Ng, K-C., O’Connor, F! A., & Schonfeld. I. S. (1986). Ten-year consistency in ne~lo~c~ test performance of children without focal neurological deficit. Developmental Medicine and Child Neurology, 28,417~427. Snow, J. H., Blondis, T., & Brady, L. (1988). Motor and sensory abilities with normal and academically at-risk children. Archives of Clinical Neuropsychology, 3,227-238. Thurstone, L. (1968). Primary mental abilities. Chicago: Chicago University Press. Vanderplas, J. M., & Garvin, E. A. (1959). The association value of random shapes. Journal of Ex~ri~ntai Psychology, 57,147-L% Vygotsky, L. S. (1965). Psychology and localization of functions. Ne~op~c~logia, 3,381-386. Witelson, S. F. (1974). Hemispheric specialization for linguistic and nonlinguistic tactual perception using dichotomous stimulization technique. Cortex, 10,3-17. Witelson, S. F. (1976). Sex and the single hemisphere: Specialization of the right hemisphere for spatial processing. Science, 193,425-427. Woodcock, R. W., & Johnson, M. B. (1977). Woodcock-Johnson psycho-educational battery. Allen, TX: DLM Teaching Resources.
6, pp. 271-278,
1991 Copyright
oaa7-6177/91$3.00+ .oo 0 1991 National Academy of Neuropsychology
Neuropsychological
Skills With
Motor
and Motor
Dysfunctional
Normal Children Jeffrey H. Snow New Medico Rehabilitation
Center, Timber Ridge Ranch
Thomas A. Blondis University of Missouri School of Medicine
Richard A. English University of Missouri-Columbia
A group of 40 children was selected from a larger sample based on their performance on motor coordination, motor speed, and motor inhibition tasks. Twenty of Ihe children were classified as Motor Dysfunctional (MD) and 20 were classified as Motor Normal (MN). The groups were compared on several neuropsychological measures. The results indicated Ihe MD children were significantly lower on a number of measures, particularly those requiring sensory integration. There were not sign$cant dif/erences on several of Ihe tasks, including those more complex in nature. The results are discussed in relation to developmenral models of neuropsychological functioning.
The examination of motor skills is an integral part of any neuropsychological assessment conducted with children (see Gaddes, 1985 and Rourke, Bakker, Fisk, & Strang, 1983). Testing and analysis has proven beneficial in understanding of the motor “clumsy” child (Bax & Whitmore, 1987; Lord & Hume, 1987). Lord and Hume found that children who were motor clumsy performed This project was supported in part by a grant from the Center for Educational Assessment, University of Missouri-Columbia College of Education. Requests for reprints should be sent to Jeffrey H. Snow, New Medico Rehabilitation Center, Tiiber Ridge Ranch, PO. Box 90, Benton, AR 72015. 271
272
J. H. Snow, T. A. Blondis, and R. A. English
significantly poorer than normal children on motor tasks. Additionally, they found that the clumsy children were also significantly lower on measures of visual-spatial processing which led the authors to conclude that poor visual processing may be related to poor motor performance. Bax and Whitmore found that motor clumsy children were significantly more at-risk for learning problems than were children with normal motor skills. The importance of incorporation of motor assessments is supported from a clinical perspective. For example, Bawden, Knights, and Winogran (1985) examined speeded and nonspeeded performance with head-injured children. These authors found that speeded performance (which was largely assessed using tasks which required a motor response) was significantly more impaired for the severely head-injured children as opposed to the mildly and moderately head-injured children. Snow, Blondis, and Brady (1988) found motor speed and motor coordination tasks to contribute significantly to the discrimination of academically at-risk children from normal children. The intent of the present study was to examine the neuropsychological performance of children who evidence motor difficulties as compared with children who had normal motor functioning. Children with dysfunctional motor skills were selected and normal controls were matched to this group. Followup comparisons were completed with other neuropsychological measures. The purpose of this study was to provide more comprehensive data concerning neuropsychological profiles of motor dysfunctional children.
METHOD Subjects The subjects for this study consisted of 40 children between the ages of 6 and 11 years. The children were selected from randomly generated lists of students enrolled in regular education. The mean age in months for the entire sample was 107.28 with a standard deviation of 20.65. There were 22 males and 18 females. In terms of racial composition, all of the children were white. Twenty of the children were classified as Motor Dysfunctional (MD) and 20 were classified as Motor Normal (MN). Each of these groups consisted of 11 males and 9 females. The children were randomly selected from four Missouri school districts. Measures Motor Coordination. Derived from Shafer et al. (1986) this task consisted of repetitive hand pronation-supination. This was scored for periodicity (uniformity of movement) for each hand, alternation for each hand, and precision in hitting a target for each hand.
273 Associated Movements. Also derived from Shafer et al. (1986), mirror movements were examined for each child as an index of motor overflow. The child opposed each finger of his or her hand to his or her thumb in succession. The nonperforming hand was observed for degree of movement during the task. This task was scored for amount (i.e, distance} of movement with the nonperforming hand and frequency of movement with the non~rfo~ing hand. Motor Speed. Also derived from Shafer et al. (1986), this measure consisted of
timed performances on the hand pronation-supination and successive finger touching tasks. In addition, timed performances were also obtained on a heel-toe alternation task. Tactile Integration. Graphasthesia was used to assess tactile integration skills for both the right and the left hands. The child was shown a sheet that had three figures (triangle, square, circle), three numbers (3,5, 8), and three letters (II, F, P). Following correct recognition of the stimuli, he or she then closed his or her eyes and all nine of the forms were drawn on the back of each hand. Auditory Memory. A modified version of the Memory for Sentences subtest from the Woodcock-Johnson Psychoeducational Battery (Woodcock & Johnson, 1977) was used to assess short-term auditory memory. The task consisted of 20 sentences, with the length and complexity of each sentence gradually increasing. Visual-Spatial Analysis. Mental rotation was used to assess visual-spatial manipulation skills. The task was adapted from Thurstone (1968). Cards were presented to the subjects with an upright stimulus at the top and three rotated stimuli below. Two of the stimuli below were mirror images and the third was the correct response. A total of 28 stimulus cards were scored with 12 consisting of letters, 8 consisting of objects, and 8 consisting of figures. ~s~l Mutching. A timed matching task was used to assess visual integration skills. This task was a modified version of The Underlining Test (Rourke & Gates, 1980). For this task, the child was presented separate sheets of paper with one-, two-, and three-letter combinations at the top. The child was instructed to find al1 of the letter patterns which matched the stimulus and to circle them. The child was given 60 seconds for each sheet. Cruss-se~s~~ ~~tegr~f~~~. Dichaptic matching derived from Witelson (1974, 1976) was used to assess cross-modal integration. The task utilized 12 wooden blocks. The blocks were four- and eight-point nonsense shapes randomly selected from Vanderplas and Garvin’s (1959) associative values for random shapes. All of the shapes were drawn on a card for subject responding. Each child was instructed to close his or her eyes. A different shape was placed in each hand and the subject was allowed to manipulate these shapes for five seconds. Following shape presentation, the subjects opened their eyes and pointed to the shapes they recognized feeling. During the pointing phase, the subjects
274
J. H. Snow, T. A. Blondis, and R. A. English
clasped their hands to control for any pointing hand X shape effect. The task consisted of 20 stimulus pair presentations, with the first 10 as practice trials. Auditory Integration. A word blending task adapted from the Woodcock-Johnson (1977) was used to assess auditory integration. Words were broken down into distinct sounds and presented to the subjects with a one-second interval between each sound. The subjects were instructed to listen to the sounds and to identify the word that those sound make. The task consisted of 14 stimulus words with practice-training items. The entire subtest was administered to all of the children. Verbal Output. Word fluency derived from the McCarthy Scales of Children’s Abilities (1972) was used to assess verbal output. The child was instructed to generate as many words as possible in defined categories. The categories were animals, things to eat, and things to ride in. The subjects were given 30 seconds for word generation in each category. Procedure Signed parental permission was obtained for each child prior to testing. Each child was seen on an individual basis and administered the battery by a trained examiner. The order of administration for the different measures was determined randomly prior to data collection and was the same for all of the subjects. The sample for this study was drawn from a larger sample of children. Utilizing the larger sample (N = 169), raw scores were converted to T-scores (M = 50; SD = 10) by age level. Criteria for the MD group were as follows: (i) T-scores above 60 on at least three of the six motor measures (i.e., right- and left-hand motor coordination, right- and left-hand-associated movements, and right- and left-side motor speed); and (ii) no T-scores below 50 on any of the motor measures. Criteria for the MN group were as follows: (i) no T-scores above 60 on any of the motor measures: and (ii) at least three of the six motor T-scores below 50. The MN children were matched to the MD children in terms of sex and age.
RESULTS Table 1 lists the means and standard deviations for the two groups. The MD children were considerably higher on the motor indices which would be expected given that these were the criteria for classification. There was some variability with the other measures, but generally the MD children were more impaired. Factor Analysis Utilizing the larger sample, a factor analysis was conducted. Using Principal Components analysis with an eigenvalue greater than one criteria,
Neuropsychological Skills
275
TABLE 1 Means and Standard Deviations for Both Groups on Each Variable Group MD
M
Variable Motor
Coord. Right Motor Coord. Left
63.65 58.15
Motor Speed Right Motor Speed Left Assoc. Mov. Right Assoc. Mov. Left Graph. Right Graph. Left Memory for Sent. Mental Rotation Visual Discrim. Cross-Modal Right Cross-Modal Left Auditory Blending Word Fluency
60.35 59.60 60.40 56.40 44.15 45.15 46.80 48.90 42.80 45.65 50.15 45.85 48.70
MN SD
M
SD 8.56 11.04 13.88 14.10 10.42 10.33 9.55 9.50 8.42 11.13 7.55 9.17 8.20 11.60 9.76
44.20 42.85 44.00 46.40 49.05 45.65 53.80 54.40 51.40 54.15 55.90 58.55 55.05 53.20 53.70
4.94 4.42 6.97 6.29 1.39 10.87 9.38 7.07 8.45 8.62 9.10 9.24 10.76 6.18 9.27
six factors were retained for rotation. These factors accounted for approximately 67% of the variance. Table 2 lists the rotated factor structure for the battery. Factor 1 had moderate to high loadings from the motor speed and word fluency tasks. Factor 2 appears to reflect integrative visual and crossmodal skills with moderate to high loadings from visual discrimination, mental rotation, and dichaptic matching. Factor 3 had high loadings from the associated movement measures while factor 4 reflects motor coordination.
TABLE 2 Factor Structure for the Test Batterv Factor Variable Motor Coord. Right Motor Coord. Left Motor Speed Right Motor Speed Left Assoc. Mov. Right Assoc. Mov. Left Graph. Right Graph. Left Memory for Sent. Mental Rotation Visual Discrim. Cross-Modal Right Cross-Modal Left Auditory Blending Word Fluency
I
II
III
IV
V
VI
.18 .07 .83 .80 .04 -.09 -.12 .02 -.48 -.14 -.02 -.07 .23 -.08 -.58
-.03 -.15 .Ol .07 .08 .02 .07 .22 -.Ol .58 .43 .73 .78 .16 .06
.07 .07 -.13 -.ll .89 .85 -06 .03 -.09 .12 -04 -.02 .04 .04 -.20
.I6 .80 .20 .22 -.02 .14 -.12 -06 -.05 -.26 -.14 .07 -SK -.03 .40
-. 14 -.05 -.13 -.13 -.03 -00 .86 .80 -.ll -.lO -.18 .15 .ll .08 .03
.02 -.03 -.15 -.16 -.04 .04 -.Ol .06 .50 .07 -.39 .03 08 .82 -.12
276
J. H. Snow, T. A. Blondis, and R. A. English
Factor 5 was a tactile integration factor with high loadings from graphasthesia and factor 6 appears to reflect auditory processing with moderate to high loadings from memory for sentences and word blending. Analysis of Word Fluency Abilities Word fluency loaded on the first factor along with motor speed. The results of the t-test comparison for word fluency approached, but was not statistically significant (t(39) = 1.66, p > .OS). Analysis of Visual Integrative
Functioning
Measures which loaded on the second factor (i.e., mental rotation, visual discrimination, dichaptic matching) were combined and a MANOVA was run. The results indicated a significant difference (Pillai’s Trace F(4,35) = 9.46, p < .OOOl). Examination of univariate ANOVA’s indicated significance for visual discrimination (F(1,38) = 24.54; p < .OOOl) and dichaptic matching with the right hand (F(1,38) 19.63; p < .OOOl). With both measures, the MN group was higher than the MD group. Significance was not reached with mental rotation (F(1,38) = 2.78; p > .05) nor with dichaptic matching with the left hand (F(1,38) = 2.63; p > .05). Analysis of Tactile Integration
Abilities
Scores for graphasthesia right and was conducted. The results indicated F(2,37) = 7.51; p < .OOl). Examination significance for both the right (F(1,38) 10.67; p < .002) hands. The MN group group on both of these measures. Analysis of Auditory tntegralion
left were combined and a MANOVA a significant difference (Pillai’s Trace of the univariate ANOVAs showed = 9.14; p < .004) and left (F(1,38) = was significantly higher than the MD
Skills
The final comparison was made between the groups on the memory for sentences and auditory blending subtests. The MANOVA with these measures reached significance (F(2,27) = 3.70; p < .03). The univariate ANOVAs indicated a significant difference for the auditory blending subtest (F(1,38) = 6.26; p < .Ol) but not for the memory for sentences subtest (F(1,38) 2.97; p > .05). The MN group was higher than the MD group on the blending test.
DISCUSSION In examining the pattern of results, it is apparent that the MD children were significantly more impaired than the MN children with basic sensory integra-
Neuropsychological Skills
277
tion/discrimination. This was evidenced by bilateral depression on the graphasthesia subtest, low performance on the visual matching task, and difficulty with auditory blending. This would suggest dysfunction in base neuropsychological skills beyond those involving motor systems. The bilateral depression with tactile integration skills may, in part, account for difficulties with motor performance. This would be the case particularly with motor speed and motor coordination since these skills are so closely tied with adequate kinesthetic feedback. The MD children were not, however, significantly below the MN children on all of the measures administered. Nonsignificant differences were observed for word fluency, mental rotation, dichaptic matching with the left hand, and memory for sentences. The characteristics of these subtests include little or not reliance on any type of motor response. Task complexity may be another factor influencing observed differences. Developmental neuropsychological theories tend to be hierarchical in nature (See Rourke, 1984; Vygotsky, 1965). With these models it would be predicted that if base functional systems are dysfunctional, then latter developing more complex systems will generally be impaired. With the present study the base sensory-motor systems were clearly dysfunctional for the MD children, yet, as stated above, performance was equivocal for several of the more complex tasks. This finding does not support a hierarchical view of neuropsychological development. An alternative explanation would be dysfunction-functional reorganization. Given the functional system for more complex tasks changes with age, this would suggest there are qualitatively different means to accomplish the same end. In other words, original functional systems may have been impeded by dysfunctional development and then compensated for by altemative systems. This possible explanation is tentative and needs to be investigated further both experimentally and longitudinally. The results of this investigation are somewhat different from those reported in an earlier study (Boll, Berent, & Richards, 1976). These investigators found that normals and brain-damaged children classified on the basis of tactile-perceptual abilities (i.e., good vs. poor) were significantly different on measures of motor speed and higher cognitive functioning. The primary difference between the present study and the Boll et al. investigation relates to the classification variables in that those employed by Boll et al. were more sensitive to generalized cortical functioning. In summary, the present study indicated that MD children did show impaired performance on several neuropsychological measures when compared to MN children. The results point toward a generalized deficit in basic sensory-motor integrative skills, but not necessarily with skills independent of motor functioning. Caution should be exercised when considering these results because of the relatively small sample size employed. Replication with a substantially larger and more diverse sample is certainly warranted. In addition, longitudinal investigations with MD and MN children would shed light on the developmental rela-
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tionship between higher neuropsychological skills and lower motor functions. The present study indicated the MD children either did not suffer impaired development or had the capacity to use com~nsato~ strategies. Di~erentia~g between these and other explanations would be of both practical and theoretical significance in the area of developmental neuropsychology.
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