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Journal of Clinical and Experimental Neuropsychology Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/ncen19
Neuropsychological functioning of hydrocephalic children Jacques Donders Canady a
a b
a
, Byron P. Rourke & Alexa I.
b
University of Windsor ,
b
Department of Neurosurgery , Children's Hospital of Michigan , Detroit Published online: 04 Jan 2008.
To cite this article: Jacques Donders , Byron P. Rourke & Alexa I. Canady (1991) Neuropsychological functioning of hydrocephalic children, Journal of Clinical and Experimental Neuropsychology, 13:4, 607-613, DOI: 10.1080/01688639108401075 To link to this article: http://dx.doi.org/10.1080/01688639108401075
PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sublicensing, systematic supply, or distribution in any form to anyone is expressly
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Journal of Clinical and Experimental Neuropsychology 1991, Vol. 13, NO.4, pp. 607-613
0168-8634/91/1304-0607$3.00 Q Swets & Zeitlinger
BRIEF REPORT
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Neuropsychological Functioning of Hydrocephalic Children* Jacques Donders1*2,Byron P. Rourke', and Alexa I. Canady2 'University of Windsor 'Department of Neurosurgery, Children's Hospital of Michigan, Detroit
ABSTRACT A group of 30 five- to eight-year-old hydrocephalic children was administered a comprehensive battery of neuropsychological tests. As a group, they displayed a pattern of lower PIQ than VIQ.Their performance was within the average range of many neuropsychological tests, but they performed poorly on some measures of complex visuospatial functioning. It is concluded that hydrocephalic children at this early age exhibit relatively reduced efficiency in processing complex or novel nonverbal stimuli. The possibility of dysfunction in the posterior regions of the right cerebral hemisphere is discussed.
It is well known that measures of nonverbal intelligence are often relatively lower than measures of verbal intelligence in children with infantile hydrocephalus (Dennis et al., 1981). Other aspects of the development of hydrocephalic children are less clear. Many neuropsychological studies of hydrocephalic children have focused on a limited number of variables. For example, some investigations have dealt exclusively with perceptual or motor functions (Anderson & Plewis, 1977; Soare & Raimondi, 1977). while others focused on memory (Cull & Wyke, 1984; Tromp & Van den Burg, 1982) or language functions (Dennis, Hendrick, Hoffman, & Humphreys, 1987; Tew, 1979). However, such studies do not provide an integrated impression of the overall neuropsychological profile of hydrocephalic children. Only a few investigations have reported on comprehensive neuropsychological assessments of hydrocephalic children (Hurley, Laatsch, & Dorman, 1983; Zeiner, Prigatano, Polley, Biscoe, & Smith, 1985). In general, the literature suggests two main areas of neuropsychological dysfunction in hydrocephalic children. Some deficits appeared on verbally oriented
* An extended report of this study is available from Jacques Donders, Ph.D.. who is now at Department of Psychology, Mary Free Bed Hospital, 235 Wealthy S.E.,Grand Rapids, Michigan 49503,USA. Accepted for publication: September 11, 1990.
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tasks, such as the understanding of grammar (Dennis et al., 1987) or the recall of a word list (Tromp & Van den Burg, 1982). Other studies have reported deficits on visuospatially oriented tests, such as the copying of line drawings (Soare & Raimondi, 1977). or the recall of geometric designs (Zeiner et al.. 1985). The majority of the investigations in the literature have found more deficits on “visuospatial” tasks than on “verbal” tasks. The purpose of the present study was to investigate the pattern of performance of hydrocephalic children on a comprehensive neuropsychological test battery that would include a diversity of “verbally” oriented tasks as well as various “visuospatially” oriented tasks. Psychological tests were selected that had documented reliability and validity, as well as age norms. For heuristic purposes, we attempted to construct a battery that would allow comprehensive assessment of neuropsychological functions with as few tests as possible. Additionally, we included equal numbers of tests of “verbal” abilities and of “visuospatial” abilities. For both these categories we selected tests of “receptive” skills as well as tests of “expressive” skills, and tests of memory and problem-solving, Measures of psychometric intelligence were also included. Hypothesis 1 was that hydrocephalic children as a group would have a significantly lower PIQ than VIQ on the Wechsler scales. Hypothesis 2 was that additional neuropsychological testing would also reveal (a) neuropsychological deficits on tests of visuospatial skills, and (b) less impairment on tests of verbal or language-related skills. METHOD Subjects The 30 subjects for this study were selected from a larger cohort of children who were participating in a project involving the psychological follow-up of hydrocephalic children at Children’s Hospital of Michigan. The procedures for the selection of the subjects have been described in detail elsewhere (Donders, Canady, & Rourke, 1990). Specifically for this study, only subjects whose VIQ and PIQ measures on the Wochsler scales exceeded 70 were included (so that any neuropsychological deficits would not be attributable to mental retardation). Of the 48 children that were available for testing. 4 were excluded because their VIQ and PXQ were both below 70. In addition, 14 other children were excluded because they were mentally retarded to the degree that it was impossible to engage them in psychometric testing. All subjects were between 5.6 and 8.6 years at the time of assessment: 17 subjects were males, 13 were females; 25 subjects were righthanded, 5 were left-handed. Psychological tests
Psychometric intelligencewas assessed in subjects above the age of 6.5 years (n = 16) with the Wechsler Intelligence Scale for Children - Revised (WISC-R Wechsler, 1974). Those below this age were administered the Wechsler Preschool and Primary Scale of Intelligence (WPPSI; Wechsler, 1969). Fouaeen additional psychological tests were selected on a theoretical basis, according to the criteria described above (rather than through factor analysis of existing batteries). First, the following subtests from the Kaufman Assessment Battery for Children (KABC;
609
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Kaufman & Kaufman, 1983) were selected: Gestalt Closure, Matrix Analogies, Spatial Memory, and Riddles. Second, the following subtests fromthe McCarthy Scales of Children’s Abilities (MSCA; McCarthy, 1972) were also included: Draw-A-Design, Verbal Fluency, and Verbal Memory 11. Finally, we selected the Children’s Word Finding Test (CWFT; Rourke & Fisk, 1976), Matching Figures Test (Reitan & Davison, 1974). Peabody Picture Vocabulary Test - Revised (PPVT-R; Durn & Dunn, 1981). Progressive Figures Test (Reitan & Davison, 1974), Selective Reminding Test (Morgan, 1982), Target Test (Reitan & Davison, 1974), and Token Test for Children (DiSimoni, 1978).
Procedure Parents of patients were contacted by telephone for voluntary participation. The research nature and purpose of the study were fully explained. Informed written consent was then obtained from all parents, and all children verbally assented to the assessment. Each subject was assessed during two 2-hour sessions on a single day. The obtained performances on each of the psychological tests were converted to linear T scores, based on the means and standard deviations of the norms for each test. This was done in such a way that better than average performances were indicated by T scores above 50 and less than average performances by T scores below 50. RESULTS The average performances of the entire sample on all psychological tests are presented in Table 1. The IQ scores are presented in the standard manner. All
Table 1. Performance on psychological test measures (see text for details).
M
SD
102.33 93.33 97.57
14.02 13.24 13.09
VERBALLY ORIENTED MEASURES CWFT Total items correct PPVT-R Standard Score Riddles Standard Score Selective Reminding Consistent long-term recall Token Test Total items correct Verbal Fluency Total words in four trials Verbal Memory II Total items correct
49.62 49.44 50.24 44.30 45.74 53.70 49.00
10.79 9.96 9.13 8.18 12.77 10.30 8.29
VISUOSPATIALLY ORIENTED MEASURES Draw-A-Design Total score on nine items Gestalt Closure Scaled Score Matching Figures Time (secs) for completion Matrix Analogies Scaled Score Progressive Figures Time (secs) for completion Spatial Memory Scaled Score Target Test Total items correct
41.26 45.33 51.10 51.22 47.90 44.00 36.40
11.24 9.08 7.12 6.81 11.19 8.94 10.87
VARIABLE
NATURE OF SCORE WISC-R\WPPSI Verbal IQ WISC-R\WPPSI Performance IQ WISC-R\WPPSI Full-scale IQ
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other measures are presented in T scores (with a mean of 50 and a standard deviation of 10). A paired-samples t test revealed that the average VIQ was significantly higher than the average PIQ (r (29) = 3.848, p < .OOl). However, both measures were within the average range. Inspection of Table 1 also reveals that the average T scores were within the average range on almost all selected neuropsychological measures, with the exception of the Target Test. A marginal (but not clearly impaired) level of performance was exhibited on the Draw-A-Design subtest of the MSCA.
DISCUSSION The PIQ scores of the hydrocephalic sample in this study tended to be somewhat lower than the VIQ scores. This is in accord with the expectation contained in Hypothesis 1. However, the amount of the difference was modest (about nine points) and the average PIQ of the entire sample was still within the average range. The latter may be partly due to the fact that we included in this study only children with IQ scores above 70. Dennis et al. (1981) also restricted their sample to children whose VIQ and PIQ scores exceeded 70. The mean VIQ and PIQ values in their sample were 96.19 (SD13.75) and 86.60 (SD 13.70) respectively; these values are consistent with our results. The second purpose of this study was to investigate the neuropsychological profile of hydrocephalic children. The only neuropsychologicaltest that revealed a T score (averaged over all subjects) in the impaired range was the Target Test. This cannot be interpreted as an unequivocal confirmation of Hypothesis 2, since the performance of the subjects was within normal limits on several other tests of visuospatial skills. It appears that, at least in a selective sample of children who are not significantly mentally retarded, infantile hydrocephalus is not associated with pervasive neuropsychological deficits at the age between five and eight years. However, subtle deficits are apparent at this early age in performance on some complex visuospatial measures (PIQ, Target Test, and to a lesser degree Draw-A-Design). These findings may suggest a relatively reduced efficiency of visuospatial skills in hydrocephalic children. There is a possibility this may become more manifest and more significant as the children become older (when environmental demands and the complexity of academic tasks increase). Several cautions need to be made with regard to this interpretation. First of all, this was a small sample, and the findings need independent replication. If replication with a larger sample could be accomplished then it might also be possible to explore in more detail the factor analytic structure of the assessment battery, or to identify neuropsychological subtypes or clusters of hydrocephalic children. Second, the importance of the word "relatively" cannot be overstated. By no means do we wish to imply that all hydrocephalic children do poorly on
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61 1
every “visuospatial” task. We merely suggest that, even at these early ages, they tend to perform somewhat inefficiently on such tasks. Comparison of our results with those of some other studies reported in the literature reveals similarities as well as differences. The poor performance on the Target Test, a measure which has excellent reliability (Brown, Rourke, & Cicchetti, 1989), is consistent with the deficits in nonverbal recall that have been reported in children with shunted uncomplicated hydrocephalus (Zeiner et al., 1985). The marginal performance on Draw-A-Design is also consistent with the findings of other studies that have indicated deficient performance of hydrocephalic children on tasks requiring copying of line drawings (e.g., Soare & Raimondi, 1977). Unlike Dennis et al. (1987). we did not find a selective effect of hydrocephalus on understanding of grammar, since our subjects performed within normal limits on the Token Test. Finally, we also did not find evidence for verbal memory deficits in hydrocephalic children, as some other researchers (e.g., Cull & Wyke, 1984; Tromp & Van den Burg, 1982) have reported. These differences may be due to the fact that these other investigators used experimental measures without adequate age norms. We can only speculate about the meaning of the suggested reduced efficiency of complex visuospatial skills in hydrocephalic children. We feel confident that this is not due only to ocular or fine motor dysfunctions. Several studies have shown that a history of ocular defects is associated not only with impairment of PIQ, but also with impairment of VIQ (Donders, Canady, & Rourke, 1990; Zeiner et al., 1985). Furthermore, even children with significant upper extremity coordination problems could perform the motoric aspects of the Target Test without much difficulty. We offer the possibility that the relative inefficiency of hydrocephalic children on some visuospatial measures is a reflection of persistent dysfunction in the posterior regions of the right cerebral hemisphere (possibly involving especially the white matter in these regions). The data from this study do not allow a direct evaluation of the relationship between lesion localization and neuropsychological outcome. However, there are facts that support our suggestion of posterior right cerebral dysfunction. First of all, the initial shunt is usually placed in this region (Bell & McCormick, 1978). In addition, there is more white matter and interregional integration in the right hemisphere than in the left hemisphere, and hydrocephalus tends to be especially destructive of white matter (Gabriel, 1980 Hammock & Milhorat, 1981). It has been suggested that such white matter interregional connections are crucial for many visuospatial tasks that require processing of novel or complex stimuli (Goldberg & Costa, 1981; Rourke, 1987, 1988, 1989). In summary, the performance of five- to eight-year-old hydrocephalic children appears to be within normal limits on many neuropsychological tests. However, they may have relatively reduced efficiency in dealing with complex or novel visuospatial stimuli. This would not appear to be attributable to simple sensory or motor factors, but may be related to dysfunction of white matter within the posterior regions of the right cerebral hemisphere. The implications for the de-
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velopment of these children (e.g., with regard to possible future difficulties with nonverbal problem-solving or adapting to new situations) need t o be addressed in future research.
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REFERENCES Anderson, EM., & Plewis, I. (1977). Impairment of a motor skill in children with spina bifida cystica and hydrocephalus: An exploratory study. British Journal of Psychology, 68,61-70. Bell, W.E., & McCormick, W.F. (1978). Increased intracranial pressure in children: Diagnosis and treatment (2nd ed.). Philadelphia: W.B. Swnders Company. Brown. S.J.. Rourke. B.P.. & Cicchetti. D.V. (1989). Reliability of tests and measures used in neuropsychological assessment of children. The C l i & z l Neuropsychologist, 3.353-368.
Cull; C., & Wyke, M.A. (1984). Memory function of children with spina bifida and shunted hydrocephalus. Developmental Medicine and Child Neurology, 26, 177-183. Dennis, M., Fitz, C.R., Netley. C.T., Sugar, J., Harwood-Nash, D.C.F.. Hendriclc, E.B., Hoffman, H.J.. & Humphreys. R.P. (1981). The intelligence of hydrocephalic children. Archives of Neurolo y , 38, 607-615. Dennis, M.. Hendrick. $.B., Hoffman, H.J., & Humphreys, R.P. (1987). The language of hydracephalic children and adolescents. Journal of Clinical and Experimental Neuropsychology, 9,593-621. DiSimoni. F. (1978). Token Testfor Children. Hingham, MA: Teaching Resource Corporation. Donders, J., Canady, A.I., & Rourke, B.P. (1990). Psychometric intelligence after infantile hydrocephalus: A critical review and reinterpretation. Child's Nervous System, 6, 148-154.
Dunn, L.M., & Dunn, L. (1981). Peabody Picture Vocabulary Test - Revised. Circle Pines, MN:American Guidance Service, Inc. Gabriel, R.S. (1980). Malformations of the central nervous system. In J.H. Menkes (Ed.), Textbook of child neurology (pp. 161-237). Philadelphia: Lea & Febiger. Goldberg, E.,& Costa, L.D. (1981). Hemispheric differences in the acquisition and use of descriptive systems. Brain and Language, 14, 144-173. Hammock. M.K..& Milhorat. T.H. (1981). Malformations of the central nervous system. In M.Coleman (Ed.), Neonatal neurology (pp. 299-303). Baltimore: University Park press. Hurley, A.D., Laatsch, L.K., & Donnan, C. (1983). Comparison of spina bifida hydrocephalic patients and matchedcontrols on neuropsychologicaltests. Zeitschr@@ Kinderchirurgie, 38 (Supplement 2). 116-118. Kaufman, A.S.. & Kaufman. N.L. (1983). Kalrfman Assessment Battery for Children. Cicle Pines, M N : American Guidance Service, Inc. McCarthy, D. (1972). McCarthy Scales of Children's Abilities. New York: Psychological Corporation. Morgan, S.F. (1982). Measuring long-term storage and retrieval in children. Journal of Clinical Neuropsychology, 4 , 177-185. Reitan. R.M., & Davison, L.A. (1974). Clinical neuropsychology: Current s t a t u and applications. Washiqgton, DC: V.H. Winston. Rourke, B.P. (1987). Syndrome of nonverbal learning disabilities: The rial common pathway of white-matter diseaseldysfunction? The Clinical Neuropsychologist, I , 209234.
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Rourke, B.P. (1988). The syndrome of nonverbal learning disabilities: Developmental manifestations in neurological disease, disorder, and dysfunction. The Clinical Neuropsychologist, 2 , 293-330. Rourke, B.P. (1989). Nonverbal learning disabilities: The syndrome and the model. New York Guilford Press. Rourke, B.P., & Fisk, J.L. (1976). Children’s Word Finding Test (revised). Windsor: University of Windsor. Soare, P.L., & Raimondi, A.J. (1977). Intellectual and perceptual-motor characteristics of treated myelomeningocele children. American Journal of Diseases of Children, 131, 199-204.
Tew, B. (1979). The “cocktail party syndrome” in children with hydrocephalus and spina bifida. British Journal of Disorders of Communication,14, 89-101. Tromp, C.N., & Van den Burg, W. (1982). Verbal memory impairment in treated hydrocephalic children. Zeitschriftf i r Kinderchirurgie, 37, 175-178. Wechsler, D. (1969). Wechsler Preschool and Primary Scale of Intelligence. New York: Psychological Corporation. Wechsler, D. (1974). Wechsler Intelligence Scale for Children - Revised. New York: Psychological Corporation. Zeiner. H.K..Prigatano. G.P.. Pollay, M., Biscoe, C.B., & Smith, R.V. (1985). Ocular motility, visual acuity and dysfunction of neuropsychological impairment in children with shunted uncomplicated hydrocephalus. Child‘s Nervous System, I , 1 1 5-122.
Journal of Clinical and Experimental Neuropsychology Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/ncen19
Neuropsychological functioning of hydrocephalic children Jacques Donders Canady a
a b
a
, Byron P. Rourke & Alexa I.
b
University of Windsor ,
b
Department of Neurosurgery , Children's Hospital of Michigan , Detroit Published online: 04 Jan 2008.
To cite this article: Jacques Donders , Byron P. Rourke & Alexa I. Canady (1991) Neuropsychological functioning of hydrocephalic children, Journal of Clinical and Experimental Neuropsychology, 13:4, 607-613, DOI: 10.1080/01688639108401075 To link to this article: http://dx.doi.org/10.1080/01688639108401075
PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sublicensing, systematic supply, or distribution in any form to anyone is expressly
Downloaded by [UZH Hauptbibliothek / Zentralbibliothek Zürich] at 21:02 06 January 2015
forbidden. Terms & Conditions of access and use can be found at http:// www.tandfonline.com/page/terms-and-conditions
Journal of Clinical and Experimental Neuropsychology 1991, Vol. 13, NO.4, pp. 607-613
0168-8634/91/1304-0607$3.00 Q Swets & Zeitlinger
BRIEF REPORT
Downloaded by [UZH Hauptbibliothek / Zentralbibliothek Zürich] at 21:02 06 January 2015
Neuropsychological Functioning of Hydrocephalic Children* Jacques Donders1*2,Byron P. Rourke', and Alexa I. Canady2 'University of Windsor 'Department of Neurosurgery, Children's Hospital of Michigan, Detroit
ABSTRACT A group of 30 five- to eight-year-old hydrocephalic children was administered a comprehensive battery of neuropsychological tests. As a group, they displayed a pattern of lower PIQ than VIQ.Their performance was within the average range of many neuropsychological tests, but they performed poorly on some measures of complex visuospatial functioning. It is concluded that hydrocephalic children at this early age exhibit relatively reduced efficiency in processing complex or novel nonverbal stimuli. The possibility of dysfunction in the posterior regions of the right cerebral hemisphere is discussed.
It is well known that measures of nonverbal intelligence are often relatively lower than measures of verbal intelligence in children with infantile hydrocephalus (Dennis et al., 1981). Other aspects of the development of hydrocephalic children are less clear. Many neuropsychological studies of hydrocephalic children have focused on a limited number of variables. For example, some investigations have dealt exclusively with perceptual or motor functions (Anderson & Plewis, 1977; Soare & Raimondi, 1977). while others focused on memory (Cull & Wyke, 1984; Tromp & Van den Burg, 1982) or language functions (Dennis, Hendrick, Hoffman, & Humphreys, 1987; Tew, 1979). However, such studies do not provide an integrated impression of the overall neuropsychological profile of hydrocephalic children. Only a few investigations have reported on comprehensive neuropsychological assessments of hydrocephalic children (Hurley, Laatsch, & Dorman, 1983; Zeiner, Prigatano, Polley, Biscoe, & Smith, 1985). In general, the literature suggests two main areas of neuropsychological dysfunction in hydrocephalic children. Some deficits appeared on verbally oriented
* An extended report of this study is available from Jacques Donders, Ph.D.. who is now at Department of Psychology, Mary Free Bed Hospital, 235 Wealthy S.E.,Grand Rapids, Michigan 49503,USA. Accepted for publication: September 11, 1990.
Downloaded by [UZH Hauptbibliothek / Zentralbibliothek Zürich] at 21:02 06 January 2015
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tasks, such as the understanding of grammar (Dennis et al., 1987) or the recall of a word list (Tromp & Van den Burg, 1982). Other studies have reported deficits on visuospatially oriented tests, such as the copying of line drawings (Soare & Raimondi, 1977). or the recall of geometric designs (Zeiner et al.. 1985). The majority of the investigations in the literature have found more deficits on “visuospatial” tasks than on “verbal” tasks. The purpose of the present study was to investigate the pattern of performance of hydrocephalic children on a comprehensive neuropsychological test battery that would include a diversity of “verbally” oriented tasks as well as various “visuospatially” oriented tasks. Psychological tests were selected that had documented reliability and validity, as well as age norms. For heuristic purposes, we attempted to construct a battery that would allow comprehensive assessment of neuropsychological functions with as few tests as possible. Additionally, we included equal numbers of tests of “verbal” abilities and of “visuospatial” abilities. For both these categories we selected tests of “receptive” skills as well as tests of “expressive” skills, and tests of memory and problem-solving, Measures of psychometric intelligence were also included. Hypothesis 1 was that hydrocephalic children as a group would have a significantly lower PIQ than VIQ on the Wechsler scales. Hypothesis 2 was that additional neuropsychological testing would also reveal (a) neuropsychological deficits on tests of visuospatial skills, and (b) less impairment on tests of verbal or language-related skills. METHOD Subjects The 30 subjects for this study were selected from a larger cohort of children who were participating in a project involving the psychological follow-up of hydrocephalic children at Children’s Hospital of Michigan. The procedures for the selection of the subjects have been described in detail elsewhere (Donders, Canady, & Rourke, 1990). Specifically for this study, only subjects whose VIQ and PIQ measures on the Wochsler scales exceeded 70 were included (so that any neuropsychological deficits would not be attributable to mental retardation). Of the 48 children that were available for testing. 4 were excluded because their VIQ and PXQ were both below 70. In addition, 14 other children were excluded because they were mentally retarded to the degree that it was impossible to engage them in psychometric testing. All subjects were between 5.6 and 8.6 years at the time of assessment: 17 subjects were males, 13 were females; 25 subjects were righthanded, 5 were left-handed. Psychological tests
Psychometric intelligencewas assessed in subjects above the age of 6.5 years (n = 16) with the Wechsler Intelligence Scale for Children - Revised (WISC-R Wechsler, 1974). Those below this age were administered the Wechsler Preschool and Primary Scale of Intelligence (WPPSI; Wechsler, 1969). Fouaeen additional psychological tests were selected on a theoretical basis, according to the criteria described above (rather than through factor analysis of existing batteries). First, the following subtests from the Kaufman Assessment Battery for Children (KABC;
609
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Kaufman & Kaufman, 1983) were selected: Gestalt Closure, Matrix Analogies, Spatial Memory, and Riddles. Second, the following subtests fromthe McCarthy Scales of Children’s Abilities (MSCA; McCarthy, 1972) were also included: Draw-A-Design, Verbal Fluency, and Verbal Memory 11. Finally, we selected the Children’s Word Finding Test (CWFT; Rourke & Fisk, 1976), Matching Figures Test (Reitan & Davison, 1974). Peabody Picture Vocabulary Test - Revised (PPVT-R; Durn & Dunn, 1981). Progressive Figures Test (Reitan & Davison, 1974), Selective Reminding Test (Morgan, 1982), Target Test (Reitan & Davison, 1974), and Token Test for Children (DiSimoni, 1978).
Procedure Parents of patients were contacted by telephone for voluntary participation. The research nature and purpose of the study were fully explained. Informed written consent was then obtained from all parents, and all children verbally assented to the assessment. Each subject was assessed during two 2-hour sessions on a single day. The obtained performances on each of the psychological tests were converted to linear T scores, based on the means and standard deviations of the norms for each test. This was done in such a way that better than average performances were indicated by T scores above 50 and less than average performances by T scores below 50. RESULTS The average performances of the entire sample on all psychological tests are presented in Table 1. The IQ scores are presented in the standard manner. All
Table 1. Performance on psychological test measures (see text for details).
M
SD
102.33 93.33 97.57
14.02 13.24 13.09
VERBALLY ORIENTED MEASURES CWFT Total items correct PPVT-R Standard Score Riddles Standard Score Selective Reminding Consistent long-term recall Token Test Total items correct Verbal Fluency Total words in four trials Verbal Memory II Total items correct
49.62 49.44 50.24 44.30 45.74 53.70 49.00
10.79 9.96 9.13 8.18 12.77 10.30 8.29
VISUOSPATIALLY ORIENTED MEASURES Draw-A-Design Total score on nine items Gestalt Closure Scaled Score Matching Figures Time (secs) for completion Matrix Analogies Scaled Score Progressive Figures Time (secs) for completion Spatial Memory Scaled Score Target Test Total items correct
41.26 45.33 51.10 51.22 47.90 44.00 36.40
11.24 9.08 7.12 6.81 11.19 8.94 10.87
VARIABLE
NATURE OF SCORE WISC-R\WPPSI Verbal IQ WISC-R\WPPSI Performance IQ WISC-R\WPPSI Full-scale IQ
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other measures are presented in T scores (with a mean of 50 and a standard deviation of 10). A paired-samples t test revealed that the average VIQ was significantly higher than the average PIQ (r (29) = 3.848, p < .OOl). However, both measures were within the average range. Inspection of Table 1 also reveals that the average T scores were within the average range on almost all selected neuropsychological measures, with the exception of the Target Test. A marginal (but not clearly impaired) level of performance was exhibited on the Draw-A-Design subtest of the MSCA.
DISCUSSION The PIQ scores of the hydrocephalic sample in this study tended to be somewhat lower than the VIQ scores. This is in accord with the expectation contained in Hypothesis 1. However, the amount of the difference was modest (about nine points) and the average PIQ of the entire sample was still within the average range. The latter may be partly due to the fact that we included in this study only children with IQ scores above 70. Dennis et al. (1981) also restricted their sample to children whose VIQ and PIQ scores exceeded 70. The mean VIQ and PIQ values in their sample were 96.19 (SD13.75) and 86.60 (SD 13.70) respectively; these values are consistent with our results. The second purpose of this study was to investigate the neuropsychological profile of hydrocephalic children. The only neuropsychologicaltest that revealed a T score (averaged over all subjects) in the impaired range was the Target Test. This cannot be interpreted as an unequivocal confirmation of Hypothesis 2, since the performance of the subjects was within normal limits on several other tests of visuospatial skills. It appears that, at least in a selective sample of children who are not significantly mentally retarded, infantile hydrocephalus is not associated with pervasive neuropsychological deficits at the age between five and eight years. However, subtle deficits are apparent at this early age in performance on some complex visuospatial measures (PIQ, Target Test, and to a lesser degree Draw-A-Design). These findings may suggest a relatively reduced efficiency of visuospatial skills in hydrocephalic children. There is a possibility this may become more manifest and more significant as the children become older (when environmental demands and the complexity of academic tasks increase). Several cautions need to be made with regard to this interpretation. First of all, this was a small sample, and the findings need independent replication. If replication with a larger sample could be accomplished then it might also be possible to explore in more detail the factor analytic structure of the assessment battery, or to identify neuropsychological subtypes or clusters of hydrocephalic children. Second, the importance of the word "relatively" cannot be overstated. By no means do we wish to imply that all hydrocephalic children do poorly on
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every “visuospatial” task. We merely suggest that, even at these early ages, they tend to perform somewhat inefficiently on such tasks. Comparison of our results with those of some other studies reported in the literature reveals similarities as well as differences. The poor performance on the Target Test, a measure which has excellent reliability (Brown, Rourke, & Cicchetti, 1989), is consistent with the deficits in nonverbal recall that have been reported in children with shunted uncomplicated hydrocephalus (Zeiner et al., 1985). The marginal performance on Draw-A-Design is also consistent with the findings of other studies that have indicated deficient performance of hydrocephalic children on tasks requiring copying of line drawings (e.g., Soare & Raimondi, 1977). Unlike Dennis et al. (1987). we did not find a selective effect of hydrocephalus on understanding of grammar, since our subjects performed within normal limits on the Token Test. Finally, we also did not find evidence for verbal memory deficits in hydrocephalic children, as some other researchers (e.g., Cull & Wyke, 1984; Tromp & Van den Burg, 1982) have reported. These differences may be due to the fact that these other investigators used experimental measures without adequate age norms. We can only speculate about the meaning of the suggested reduced efficiency of complex visuospatial skills in hydrocephalic children. We feel confident that this is not due only to ocular or fine motor dysfunctions. Several studies have shown that a history of ocular defects is associated not only with impairment of PIQ, but also with impairment of VIQ (Donders, Canady, & Rourke, 1990; Zeiner et al., 1985). Furthermore, even children with significant upper extremity coordination problems could perform the motoric aspects of the Target Test without much difficulty. We offer the possibility that the relative inefficiency of hydrocephalic children on some visuospatial measures is a reflection of persistent dysfunction in the posterior regions of the right cerebral hemisphere (possibly involving especially the white matter in these regions). The data from this study do not allow a direct evaluation of the relationship between lesion localization and neuropsychological outcome. However, there are facts that support our suggestion of posterior right cerebral dysfunction. First of all, the initial shunt is usually placed in this region (Bell & McCormick, 1978). In addition, there is more white matter and interregional integration in the right hemisphere than in the left hemisphere, and hydrocephalus tends to be especially destructive of white matter (Gabriel, 1980 Hammock & Milhorat, 1981). It has been suggested that such white matter interregional connections are crucial for many visuospatial tasks that require processing of novel or complex stimuli (Goldberg & Costa, 1981; Rourke, 1987, 1988, 1989). In summary, the performance of five- to eight-year-old hydrocephalic children appears to be within normal limits on many neuropsychological tests. However, they may have relatively reduced efficiency in dealing with complex or novel visuospatial stimuli. This would not appear to be attributable to simple sensory or motor factors, but may be related to dysfunction of white matter within the posterior regions of the right cerebral hemisphere. The implications for the de-
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velopment of these children (e.g., with regard to possible future difficulties with nonverbal problem-solving or adapting to new situations) need t o be addressed in future research.
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