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Question #39


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Question # 39

What is the relationship, if any, between the Gerstmann and NLD syndromes?


Background/Findings and Conclusions

Some time ago, we found that the principal features of the Gerstmann syndrome were evident in a subgroup of children with learning disabilities (LD) who exhibited superior single-word reading and spelling within a context of significantly deficient mechanical arithmetic (Rourke & Finlayson, 1978; Rourke & Strang, 1978). This subgroup turned out to be a reliable and valid subtype of LD. We eventually found that this subtype of LD exhibited characteristics of the syndrome of NLD. And the syndrome of NLD presented with all of the deficits of the Gerstmann syndrome (GS), and then some: impaired arithmetic, bilateral finger agnosia (and other somatosensory deficits, usually more marked on the left side of the body), bilateral psychomotor incoordination (usually more marked on the left side of the body), and visual-spatial-organizational deficits (including constructional dyspraxia and deficits in directional orientation). We hypothesized that these deficits were far more likely to be the result of dysfunctional right, rather than left, hemisphere systems.

Thus, one very important distinction between the GS and the syndrome of NLD is that the latter is much more likely to be a result of dysfunctional right hemisphere systems rather than the result of a significant lesion of the left angular gyrus.

Furthermore, we hypothesized that diffuse white matter perturbations in the brain that cause, for example, diminished "access" to right hemisphere systems (as in corpus callosum dysfunction) can eventuate in the NLD syndrome. None of our research and the theoretical formulations based upon it since that time (e.g., Rourke, 1975, 1982, 1989, 1995; Rourke, van der Vlugt, & Rourke, 2002) has led us to reject this hypothesis. Indeed, these developments led to the fleshing out of the characteristics and dimensions of the NLD syndrome (see NLD Content and Dynamics).

It may be important to note that these extensions have been known for about one-quarter of a century. Their ramifications for higher-order neuropsychological functions--such as concept-formation, complex problem-solving, and the like--have also been evident for some time (e.g., Strang & Rourke, 1983). More recently, these notions have received additional support (e.g., Fisher, DeLuca, & Rourke, 1997). Of equivalent importance are the significant psychosocial ramifications of the NLD syndrome (e.g., Casey, Rourke, & Picard, 1991; Rourke, 2000; Rourke & Fuerst, 1991; Tsatsanis, Fuerst, & Rourke, 1997.) In these and other senses, NLD can be further differentiated from GS as most often involving a more pervasive impairment (i.e., more areas negatively affected) than one usually sees in GS.



Summary and Final Notes

(1) Whereas the syndrome of NLD is commonly conceptualized as a "developmental" disorder, this is not always the case; NLD can also be an acquired disorder. Indeed, one of the very first cases of NLD whom we assessed was a girl of 13 years whose development prior to a significant lesion and surgical removal of the right temporal lobe was entirely normal. Furthermore, there was no reliable evidence of any dysfunction of any systems ordinary thought to be subserved by the left cerebral hemisphere in this case (see Case #1 in Rourke, Bakker, Fisk, & Strang, 1983).

(2) We have consistently hypothesized that although the type of direct, significant disruption of functioning of right cerebral hemisphere systems as described in (1) is sufficient to eventuate in NLD, it is not necessary. And that NLD constitutes the "final common pathway" for a number of types of pediatric neurological disease, disorder, and dysfunction (e.g., Williams syndrome, Velocardiofacial syndrome, Periventricular Leukomalacia; see NLD and Neurological Disease for more examples) that, at first blush, may not appear to have any negative implications for the satisfactory functioning of right hemisphere systems or for those aspects of cognitive, adaptive, and psychosocial functioning thought to be dependent upon the adequate functioning thereof (Rourke, 1987, 1988, 1989, 1995; Rourke et al., 2002).

(3) Some limiting lesions and forms of dysfunction in the left cerebral hemisphere are hypothesized to eventuate in a subtype of LD that we refer to as Basic Phonological Processing Disabilities (BPPD). It follows that a significant lesion of the left angular gyrus is much more likely to lead to BPPD than to NLD. Indeed, our rules for the categorization of 7- to 8-year-old children are 100% sensitive to the distinction between Definite and Probable BPPD and Definite and Probable NLD (Drummond, Ahmad, & Rourke, 2005, and see question #10).

(4) H. Hecaen and M. Critchley both pointed to symptoms of the GS that were not touched upon by Gerstmann. These involved , primarily, particular types of aphasia. These observations would be consistent with those spread in (3) above.

(5) M. Kinsbourne and E. Warrington put forward the notion of a "developmental" form of the GS. Few have found this formulation helpful. Indeed, it would seem that many investigators know only of this developmental extension of the GS, and the problems associated with it. This is probably one important reason why many investigators have questioned the very "existence" of the GS as originally formulated by Gerstmann.

(6) I would invite the reader to consult the references spread below for investigations and expanded discussions of the hypotheses and models discussed herein.



References

Casey, J. E., Rourke, B. P., & Picard, E. M. (1991). Syndrome of nonverbal learning disabilities: Age differences in neuropsychological, academic, and socioemotional functioning. Development and Psychopathology, 3, 331-347.

Collins, D. W., & Rourke, B. P. (2003). Learning-disabled brains: A review of the literature. Journal of Clinical and Experimental Neuropsychology, 25, 1011-1034.

Dool, C. B., Stelmack, R. M., & Rourke, B. P. (1993). Event-related potentials in children with learning disabilities. Journal of Clinical Child Psychology, 22, 387-398.

Drummond, C. R., Ahmad, S. A., & Rourke, B. P. (2005). Rules for the classification of younger children with Nonverbal Learning Disabilities and Basic Phonological Processing Disabilities. Archives of Clinical Neuropsychology, 20, 171-182.

Fisher, N. J., DeLuca, J. W., & Rourke, B. P. (1997). Wisconsin Card Sorting Test and Halstead Category Test performances of children and adolescents who exhibit the syndrome of Nonverbal Learning Disabilities. Child Neuropsychology, 3, 61-70.

Harnadek, M. C. S., & Rourke, B. P. (1994). Principal identifying features of the syndrome of nonverbal learning disabilities in children. Journal of Learning Disabilities, 27, 144-154.

Ozols, E. J., & Rourke, B. P. (1988). Characteristics of young learning-disabled children classified according to patterns of academic achievement: Auditory-perceptual and visual-perceptual abilities. Journal of Clinical Child Psychology, 17, 44-52.

Rourke, B. P. (1975). Brain-behavior relationships in children with learning disabilities: A research program. American Psychologist, 30, 911-920.

Rourke, B. P. (1978). Reading, spelling, arithmetic disabilities: A neuropsychologic perspective. In H. R. Myklebust (Ed.), Progress in learning disabilities (Vol. 4, pp. 97-120). New York: Grune & Stratton.

Rourke, B. P. (1987). Syndrome of nonverbal learning disabilities: The final common pathway of white-matter disease/dysfunction? The Clinical Neuropsychologist, 1, 209-234.

Rourke, B. P. (1988a). Socio-emotional disturbances of learning-disabled children. Journal of Consulting and Clinical Psychology , 56, 801-810.

Rourke, B. P. (1988b). 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. (1991). Studies of persons with learning disabilities at the University of Windsor Laboratory: The first 25 years. National, 28, 41-44.

Rourke, B. P. (1993). Arithmetic disabilities, specific and otherwise: A neuropsychological perspective. Journal of Learning Disabilities, 26, 214-226.

Rourke, B. P. (1995). Introduction and overview: The NLD/white matter model. In B. P. Rourke (Ed.), Syndrome of nonverbal learning disabilities: Neurodevelopmental manifestations (pp. 1-26). New York: Guilford Press.

Rourke, B. P. (2000). Neuropsychological and psychosocial subtyping: A review of investigations within the University of Windsor laboratory. Canadian Psychology, 41, 34-50.

Rourke, B. P. (2005). Neuropsychology of learning disabilities: Past and future. Learning Disabilities Quarterly, 28, 111-114.

Rourke, B. P., Ahmad, S. A., Collins, D. W., Hayman-Abello, B. A., Hayman-Abello, S. E., & Warriner, E. M. (2002). Child-clinical/pediatric neuropsychology: Some recent advances. Annual Review of Psychology, 53, 309-339.

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 Press.

Rourke, B. P., & Conway, J. A. (1997). Disabilities of arithmetic and mathematical reasoning: Perspectives from neurology and neuropsychology. Journal of Learning Disabilities, 30, 34-46.

Rourke, B. P., Dietrich, D. M., & Young, G. C. (1973). Significance of WISC verbal-performance discrepancies for younger children with learning disabilities. Perceptual and Motor Skills, 36, 275-282.

Rourke, B. P., & Finlayson, M. A. J. (1978). Neuropsychological significance of variations in patterns of academic performance: Verbal and visual-spatial abilities. Journal of Abnormal Child Psychology, 6, 121-133.

Rourke, B.P., & Fuerst, D. R. (1991). Learning disabilities and psychosocial functioning: A neuropsychological perspective . New York: Guilford Press.

Rourke, B. P., & Fuerst, D. R. (1992). Psychosocial dimensions of learning disability subtypes: Neuropsychological studies in the Windsor Laboratory. School Psychology Review, 21, 360-373.

Rourke, B. P., & Fuerst, D. R. (1995). Cognitive processing, academic achievement, and psychosocial functioning: A neuropsychological perspective. In D. Cicchetti & D. Cohen (Eds.), Developmental psychopathology (Vol. 1, pp. 391-423). New York: Wiley.

Rourke, B. P., & Strang, J. D. (1978). Neuropsychological significance of variations in patterns of academic performance: Motor, psychomotor, and tactile-perceptual abilities. Journal of Pediatric Psychology, 3, 62-66.

Rourke, B. P., & Tsatsanis, K. D. (1996). Syndrome of Nonverbal Learning Disabilities: Psycholinguistic assets and deficits. Topics in Language Disorders, 16, 30-44.

Rourke, B. P., van der Vlugt, H., & Rourke, S. B. (2002). Practice of child-clinical neuropsychology: An introduction. Lisse, The Netherlands: Swets & Zeitlinger.

Rourke, B. P., Yanni, D. W., MacDonald, G. W., & Young, G. C. (1973). Neuropsychological significance of lateralized deficits on the Grooved Pegboard Test for older children with learning disabilities. Journal of Consulting and Clinical Psychology, 41, 128-134.

Stelmack, R. M., Rourke, B. P., & van der Vlugt, H. (1995). Intelligence, learning disabilities, and event-related potentials. Developmental Neuropsychology, 11, 445-465.

Strang, J. D., & Rourke, B. P. (1983). Concept-formation/non-verbal reasoning abilities of children who exhibit specific academic problems with arithmetic. Journal of Clinical Child Psychology, 12, 33-39.

Sweeney, J. E., & Rourke, B. P. (1978). Neuropsychological significance of phonetically accurate and phonetically inaccurate spelling errors in younger and older retarded spellers. Brain and Language, 6, 212-225.

Tsatsanis, K. D., Fuerst, D. R., & Rourke, B. P. (1997). Psychosocial dimensions of learning disabilities: External validation and relationship with age and academic functioning. Journal of Learning Disabilities, 30 , 490-502.


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