Reading and Writing

, Volume 15, Issue 1–2, pp 43–72 | Cite as

The second deficit: An investigation of the independence of phonological and naming-speed deficits in developmental dyslexia

  • Maryanne WolfEmail author
  • Alyssa Goldberg O'Rourke
  • Calvin Gidney
  • Maureen Lovett
  • Paul Cirino
  • Robin Morris


An increasing body of dyslexia researchdemonstrates, in addition to phonologicaldeficits, a second core deficit in theprocesses underlying naming speed. Thehypothesized independence of phonologicalawareness and naming-speed variables inpredicting variance in three aspects of readingperformance was studied in a group of 144severely-impaired readers in Grades 2 and 3. Stepwise regression analyses were conducted onthese variables, controlling for the effects ofSES, age, and IQ. Results indicated thatphonological measures contribute more of thevariance to those aspects of reading skill thatinvolve decoding or word attack skills;naming-speed measures contribute more to skillsinvolved in word identification. Subtypeclassification findings were equally supportiveof the independence of the two deficits: 19%of the sample had single phonological deficits;15% had single naming-speed deficits; 60% had double-deficits; and 6% could not be classified. The implications of these findingsfor diagnosis and intervention are discussed.

Dyslexia Naming speed Phonology Reading Reading disability 


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  1. Ackerman, P.T. & Dykman, R.A. (1993). Phonological processes, confrontation naming, and immediate memory in dyslexia, Journal of Learning Disabilities 26: 597-609.Google Scholar
  2. Ackerman, P.T. & Dykman, R.A. (1995). The speed factor and learning disabilities: The toll of slowness in adolescents. Unpublished manuscript.Google Scholar
  3. Adams, M.J. (1990). Beginning to read: Thinking and learning about print. Cambridge, MA: MIT Press.Google Scholar
  4. Badian, N. (1995). Predicting reading ability over the long-term: The changing roles of letter naming, phonological awareness and orthographic processing, Annals of Dyslexia: An Interdisciplinary Journal 45: 79-86.Google Scholar
  5. Badian, N. (1996a). Dyslexia: Does it exist? Dyslexia, garden-variety poor reading and the double-deficit hypothesis. Paper presented at Orton Dyslexia Society. Boston, MA.Google Scholar
  6. Badian, N. (1996b). Dyslexia: A validation of the concept at two age levels, Journal of Learning Disabilities 29: 102-112.Google Scholar
  7. Berninger, V., Cartwright, A., Yates, C., Swanson, H.L. & Abbott, R. (1994). Developmental skills related to writing and reading acquisition in the intermediate grades: Shared and unique variance, Reading and Writing: An Interdisciplinary Journal 6: 161-196.Google Scholar
  8. Biddle, K.R. (1996). The development of visual naming speed and verbal fluency in average and impaired readers: The implications for assessment intervention and theory. Unpublished doctoral dissertation. Tufts University, Boston, MA.Google Scholar
  9. Blachman, B.A. (1984). Relationship of rapid naming ability and language analysis skills to kindergarten and first-grade reading achievement, Journal of Educational Psychology 76: 610-622.Google Scholar
  10. Bowers, P.O., Golden, J., Kennedy, A. & Young, A. (1994). Limits upon orthographic knowledge due to processes indexed by naming speed. In: V.W. Berninger (ed.), The varieties of orthographic knowledge, Vol. I: Theoretical and developmental issues (pp. 173-218). Dordrecht/Boston/London: Kluwer Academic Publishers.Google Scholar
  11. Bowers, P.O., Stefty, R. & Tate, B. (1988). Comparison of the effects of IQ control methods on memory and naming speed predictors of reading disability, Reading Research Quarterly 23: 304-309.Google Scholar
  12. Bowers, P.O. & Swanson, L.B. (1991). Naming speed deficits in reading disability: Multiple measures of a singular process, Journal of Experimental Child Psychology 51: 195-219.Google Scholar
  13. Bowers, P.O. & Wolf M. (1993). Theoretical links among naming speed, precise timing mechanisms and orthographic skill in dyslexia, Reading and Writing: An Interdisciplinary Journal 5: 69-85.Google Scholar
  14. Bradley, L. & Bryant, P.E. (1983). Categorizing sounds and learning to read: A causal connection, Nature 301: 419-421.Google Scholar
  15. Brady, S. & Shankweiler, D. (eds.) (1991). Phonological processes in literacy: A tribute to Isabelle Y. Liberman. Hillsdale, NJ: Erlbaum.Google Scholar
  16. Breznitz, Z. (1996). Perceptual deficits among developmental dyslexics. Unpublished manuscript.Google Scholar
  17. Breznitz, Z. (1997). Enhancing the reading of dyslexics by reading acceleration and auditory masking, Journal of Educational Psychology 89: 103-113.Google Scholar
  18. Bruck, M. & Treiman, R. (1990). Phonological awareness and spelling in normal children and dyslexics: The case of initial consonant clusters, Journal of Experimental Child Psychology 50(1): 156-178.Google Scholar
  19. Byrne, B. (1998). The foundations of literacy. East Sussex, UK: Psychology Press.Google Scholar
  20. Carver, R.P. (1991). Using letter naming speed to diagnose reading disability, RASE-Remedial and Special Education 12: 33-43.Google Scholar
  21. Carver, R.P. (1997). Reading for one second, one minute, or one year from the perspective of reading theory, Journal for the Scientific Study of Reading 1: 4-44.Google Scholar
  22. Cattell, M. (1886). The time it takes to see and name objects, Mind 2: 63-85.Google Scholar
  23. Catts, H.W. (1996). Defining dyslexia as a developmental language disorder: An expanded view, Topics in Language Disorders 16(2): 14-29.Google Scholar
  24. Chall, J.S. (1983). Stages of reading development. New York: McGraw-Hill.Google Scholar
  25. Cornwall, A. (1992). The relationship of phonological awareness, rapid naming, and verbal memory to severe reading and spelling disability, Journal of Learning Disability 25: 532-538.Google Scholar
  26. Denckla, M.B. (1972). Color-naming defects in dyslexic boys, Cortex 8: 164-176.Google Scholar
  27. Denckla, M.B. & Rudel, R.O. (1974). 'Rapid automatized naming' of pictured objects, colors, letters, and numbers by normal children, Cortex 10: 186-202.Google Scholar
  28. Denckla, M.B. & Rudel, R.G. (1976a). Naming of objects by dyslexic and other learningdisabled children, Brain and Language 3: 1-15.Google Scholar
  29. Denckla, M.B. & Rudel, R.G. (1976b). Rapid automatized naming (R.A.N.): Dyslexia differentiated from other learning disabilities, Neuronsychologia 14: 471-479.Google Scholar
  30. Doehring, D. (1976). Acquisition of rapid reading responses, Monographs of the Society for Research in Child Development 41(2).Google Scholar
  31. Farmer, M.E. & Klein, R.M. (1995). The evidence for a temporal processing deficit linked to dyslexia: A review, Psychonomic Society 2: 460-493.Google Scholar
  32. Felton, R.H. & Wood, F. (1992). Cognitive deficits in reading deficits in reading disability and attention deficit disorder, Journal of Learning Disabilities 22: 3-13.Google Scholar
  33. Felton, R.H., Wood, F.B., Brown, I.S. & Campbell, S.K. (1987). Separate verbal memory and naming deficits in attention deficit disorder and reading disability, Brain and Language 31: 171-184.Google Scholar
  34. Fletcher, J.M., Shaywitz, S.E., Shankweiler, D.P., Katz, L., Liberman, LY., Stuebing, K.K., Fowler, A., Francis, D.J. & Shaywitz, B.A. (1994). Cognitive profiles of reading disability: Comparisons of discrepancy and low achievement definitions, Journal of Educational Psychology 85: 1-18.Google Scholar
  35. Foorman, B. (1994). Phonological and orthographic processing: Separate but equal? In: V. Berninger (ed.), The varieties of orthographic knowledge (pp. 321-358). Dordrecht/Boston/London: K1uwer Academic Publishers.Google Scholar
  36. Foorman, B., Francis, D., Shaywitz, S., Shaywitz, B. & Fletcher, J. (1997). The case for early reading intervention. In: B. Blachman (ed.), Foundations of reading acquisition (pp. 243-264). Mahwah, NJ: Erlbaum.Google Scholar
  37. Geschwind, N. (1965). Disconnection syndrome in animals and man (Parts I, II). Brain 88: 237-294, 585-644.Google Scholar
  38. Gidney, C., Deeney, T., Wolf, M., Holmes, J., Cirino, P. & Morris, R. (1998). The presence of phonological and naming-speed deficits in Africa-American children. Poster presented at the Conference on Language Development in African-American Children. Memphis, TN.Google Scholar
  39. Goldberg, A., Wolf, M., Cirino, P., Morris, R. & Lovett, M. (1998). A test of the 'Double Deficit Hypothesis'. Paper presented at the meeting of the Society for the Scientific Study of Reading. San Diego, CA.Google Scholar
  40. Gough, P. & Tunmer, W. (1986). Decoding, reading, and reading disability, Remedial and Special Education 7: 6-10.Google Scholar
  41. Grigorenko, E., Wood, F., Meyer, M., Hart, L., Speed, W., Shuster, A. & Pauls, D. (1997). Susceptibility loci for distinct components of developmental dyslexia on chromosomes 6 and 15, American Journal of Human Genetics 60: 27-39.Google Scholar
  42. Huey, B. (1908). The psychology and pedagogy of reading. Cambridge: MIT Press.Google Scholar
  43. Hurford, D.P., Johnston, M., Nepote, P., Hampton, S., Moore, S., Neal, J., Mueller, A., McGeorge, K., Huff., L., Awad, A., Tarto, C., Juliano, C. & Huffman, D. (1994). Early identification and remediation of phonological-processing deficits in first-grade children at risk for reading disabilities, Journal of Learning Disabilities 27: 647-659.Google Scholar
  44. Kamhi, A. & Catts, H. (1989). Reading disabilities: A developmental language perspective. Austin, TX: Pro-ed.Google Scholar
  45. Kaufman, A. & Kaufman, N. (1990). Kaufman Brief Intelligence Test. Circle Pines, MN: American Guidance Service.Google Scholar
  46. Korhonen, T. (1995). The persistence of rapid naming problems in children with reading disabilities: A nine-year follow-up, Journal of Learning Disabilities 28: 232-239.Google Scholar
  47. Lovett, M.W. (1992). Developmental dyslexia. In: F. Boller & J. Grafman (eds.), Handbook of Neuropsychology, Vol. 7 (pp. 163-185). Amsterdam: Elsevier.Google Scholar
  48. Lovett, M.W., Borden, S., DeLuca, T., Lacerenza, L., Benson, N. & Brackstone, D. (1994). Treating the core deficits of developmental dyslexia: Evidence of transfer of learning after phonologically and strategy-based reading training programs, Developmental Psychology 30: 805-822.Google Scholar
  49. Lovett, M., Steinbach, K. & Frijters, J. (2000). Remediating the core deficits of developmental reading disability: A double-deficit perspective, Journal of Learning Disabilities 33: 334-358.Google Scholar
  50. Lyon, G.R. (1995). Toward a definition of dyslexia, Annals of Dyslexia: An Interdisciplinary Journal 45: 3-27.Google Scholar
  51. Lyon, G.R. & Moats, L.C. (1997). Critical conceptual and methodological considerations in reading intervention research, Journal of Learning Disabilities 30: 578-588.Google Scholar
  52. Manis, F. & Doi, L. (1995). Word naming speed, phonological coding and orthographic knowledge in dyslexic and normal readers. Symposium paper presented at the Society for Research in Child Development. Indianapolis, IN.Google Scholar
  53. Manis, F., Doi, L. & Bhadha, B. (2000). Naming speed, phonological awareness and orthographic knowledge in second graders, Journal of Learning Disabilities 33: 325-333, 374.Google Scholar
  54. Martinussen, R., Frijters, J. & Tannock, R. (1998). Naming speed and stimulant effects in inattention-deficit/hyperactivity disorder. Paper presented at American Academy of Child and Adolescent Psychiatry. Anaheim, CA.Google Scholar
  55. McBride-Chang, C. & Manis, F. (1996). Structural invariance in the associations of naming speed, phonological awareness, and verbal reasoning in good and poor readers: A test of the double deficit hypothesis, Reading and Writing: An Interdisciplinary Journal 8: 323-339.Google Scholar
  56. Merzenich, M.M., Jenkins, W.M., Johnston, P., Schreiner, C., Miller, S. & Tallal, P. (1996). Temporal processing deficits of language-learning impaired children ameliorated by training, Science 271: 77-80.Google Scholar
  57. Meyer, M.S., Wood, F.B., Hart, L.A. & Felton, R.H. (1998). The selective predictive values in rapid automatized naming within poor readers, Journal of Learning Disabilities 31: 106-117.Google Scholar
  58. Morris, R., Stuebing, K., Fletcher, J., Shaywitz, S., Lyon, R., Shankweiler, D., Katz, L., Francis, D. & Shaywitz, B. (1998). Subtypes of reading disability: A phonological core with cognitive variability, Journal of Educational Psychology 90: 1-27.Google Scholar
  59. Näslund, J.C. & Schneider,W. (1991). Longitudinal effects of verbal ability, memory capacity, and phonological awareness on reading performance, European Journal of Psychology of Education 4: 375-392.Google Scholar
  60. Nicolson, R.I. & Fawcett, A.J. (1994). Reaction times and dyslexia, Quarterly Journal of Experimental Psychology 47: 29-48.Google Scholar
  61. Novoa, L. (1988). Word-retrieval process and reading acquisition and development in bilingual and monolingual children. Unpublished doctoral dissertation. Harvard University, Cambridge, MA.Google Scholar
  62. Novoa, L. & Wolf, M. (1984). Word-retrieval and reading in bilingual children. Paper presented at Boston University Language Conference, Boston, MA.Google Scholar
  63. Ojemann, G.A. (1984). Common conical and thalamic mechanisms for language and motor functions, American Journal of Physiology 246: 901-903.Google Scholar
  64. Olson, R.K. (1995). Language deficits in 'specific' reading disability. In: M. Gernsbacher (ed.), Handbook of psycholinguistics. San Diego, CA: Academic Press.Google Scholar
  65. Olson, R.K., Wise, B., Connors, F., Rack, J.P. & Fulker, D. (1989). Specific deficits in component reading and language skills: Genetic and environmental influences, Journal of Learning Disabilities 22: 339-348.Google Scholar
  66. Perfetti, C.A. (1985). Reading ability. New York: Oxford Press.Google Scholar
  67. Perfetti, C.A., Finger, B. & Hogaboam, T. (1978). Sources of vocalization latency differences between skilled and less skilled young readers, Journal of Educational Psychology 70: 730-739.Google Scholar
  68. Rutter, M. & Yule, W. (1975). The concept of specific reading retardation, Journal of Child Psychology and Psychiatry 16: 181-197.Google Scholar
  69. Sankaranarayanan, A. (1998). Cognitive profiles of youngchildren: A comparison of good and poor readers. Unpublished doctoral dissertation. Harvard University, Cambridge, MA.Google Scholar
  70. Scarborough, H.S. & Domgaard, R.M. (1998). An exploration of the relationship between reading and rapid serial naming. Poster presented at meeting of Society for Scientific Study of Reading. San Diego, CA.Google Scholar
  71. Segal, D. & Wolf, M. (1993). Automaticity, word retrieval, and vocabulary development in children with reading disabilities. In: L. Meltzer (ed.), Cognitive, linguistic, and developmental perspectives on learning disorders (pp. 141-165). Boston: Little & Brown.Google Scholar
  72. Shankweiler, D. & Liberman, I.Y. (1972). Misreading: A search for causes. In: J.F. Kavanagh & I.G.Mattingly (eds.), Language by ear and by eye (pp. 293-317). Cambridge,MA: MIT Press.Google Scholar
  73. Shaywitz, S., Shaywitz, B., Pugh, K., Fulbright, R., Constable, R.T., Menel, W.E., Shankweiler, D., Liberman, A., Skudlarski, P., Fletcher, J., Katz, L., Marchione, K., Lacadie, C., Gatenby, C. & Gore, J. (1998). Functional disruption in the organization of the brain for reading in dyslexia, Neurobiology 95: 2636-2641.Google Scholar
  74. Siegel, L.S. & Ryan, E.B. (1988). Development of grammatical-sensitivity, phonological, and short-tern memory skills in normally achieving and learning disabled children, Developmental Psychology 24: 28-37.Google Scholar
  75. Snyder, L. & Downey, D. (1995). Serial rapid naming skills in children with reading disabilities, Annals of Dyslexia 45: 31-50.Google Scholar
  76. Spring, C. & Capps, C. (1974). Encoding speed, rehearsal, and probed recall of dyslexic boys, Journal of Educational Psychology 66: 780-786.Google Scholar
  77. Spring, C. & Davis, J. (1988). Relations of digit naming speed with three components of reading, Applied Psycholinguistics 9: 315-334.Google Scholar
  78. Stanovich, K. (1986). 'Matthew effects' in reading: Some consequences of individual differences in acquisition of literacy, Reading Research Quarterly 4: 360-407.Google Scholar
  79. Stanovich, K.E. (1992). Speculations on the causes and consequences of individual differences in early reading acquisition. In: P.B. Gough, L.C. Ehri & R. Treiman (eds.), Reading acquisition (pp. 307-342). Hillsdale, NJ: Erlbaum.Google Scholar
  80. Stanovich, K.E. & Siegel, L.S. (1994). Phenotypic performance profile of children with reading disabilities: A regression-based test of the phonological-core variable difference model, Journal of Educational Psychology 86(1): 24-53.Google Scholar
  81. Tallal, P., Miller, S.L., Bedi, G., Byma, G., Wang, X., Nagarajan, S., Schreiner, C., Jenkins, W. & Merzenich, M. (1996). Language comprehension in language-learning impaired children improved with acoustically modified speech, Science 271: 81-84.Google Scholar
  82. Torgesen, J.K., Wagner, R.K. & Rashotte, C.A. (1994). Longitudinal studies of phonological processing and reading, Journal of Learning Disabilities 27: 276-286.Google Scholar
  83. Torgesen, J.K., Wagner, R.K., Rashotte, C.A., Burgess, S. & Hecht, S. (1997). Contributions of phonological awareness and rapid automatic naming ability to the growth of word-reading skills in second-to fifth-grade children, Scientific Studies of Reading 1: 161-185.Google Scholar
  84. Tunmer, W. (1995). Intervention strategies for developing onset-rime sensitivity and analogical transfer in reading disabled children. Paper presented at the Extraordinary Brain III Conference. Kauai, Hawaii.Google Scholar
  85. Van den Bos, K. (1998). IQ, phonological awareness, and continuous-naming speed related to Dutch children's poor decoding performance on two word identification tests, Dyslexia 4: 73-89.Google Scholar
  86. Vellutino, F. & Scanlon, P. (1987). Phonological coding, phonological awareness, and reading ability: Evidence from a longitudinal and experimental study, Merrill Palmer Quarterly 33: 321-363.Google Scholar
  87. Wagner, R.K., Torgesen, J.K. & Rashotte, C.A. (1994). The development of reading-related phonological processing abilities: New evidence of bi-directional causality from a latent variable longitudinal study, Developmental Psychology 30: 73-87.Google Scholar
  88. Wagner, R.K., Torgesen, J.K. & Rashotte, C.A. (1999). Comprehensive test of phonological processing. Austin, TX: ProEd.Google Scholar
  89. Wilkinson, H. (1993). Wide range achievement test: Administration manual. Wilmington, DE: Jastak.Google Scholar
  90. Wimmer, H. (1993). Characteristics of developmental dyslexia in a regular writing system, Applied Psycholinguistics 14: 1-34.Google Scholar
  91. Wimmer, H. & Hummer, P. (1990). How German-speaking first graders read and spell: Doubts on the importance of the logographic stage, Applied Psycholinguistics 11: 349-368.Google Scholar
  92. Wolf, M. (1979). The relationship of disorders of word-finding and reading in children and aphasics. Unpublished doctoral dissertation. Harvard University, Cambridge, MA.Google Scholar
  93. Wolf, M. (1982). The word-retrieval process and reading in children and aphasics. In: K. Nelson (ed.), Children's language (pp. 437-493). Hillsdale, NJ: Erlbaum.Google Scholar
  94. Wolf,M. (1991). Naming speed and reading: The contribution of the cognitive neurosciences, Reading Research Quarterly 26: 123-141.Google Scholar
  95. Wolf, M. (1997). A provisional, integrative account of phonological and naming-speed deficits in dyslexia: Implications for diagnosis and intervention. In: B. Blachman (ed.), Foundations of reading acquisition (pp. 67-92). Mahwah, NJ: Erlbaum.Google Scholar
  96. Wolf, M., Bally, H. & Morris, R. (1986). Automaticity, retrieval processes, and reading: A longitudinal study in average and impaired readers, Child Development 57: 988-1000.Google Scholar
  97. Wolf, M. & Bowers, P. (1999). The question of naming-speed deficits in developmental reading disabilities: An introduction to the double-deficit hypothesis, Journal of Educational Psychology 19: 1-24.Google Scholar
  98. Wolf, M., Bowers, P. & Biddle, K. (2000). Naming-speed processes, timing, and reading: A conceptual review, Journal of Learning Disabilities 33: 387-407.Google Scholar
  99. Wolf, M. & Goodglass (1986). Dyslexia, dysnomia, and lexical retrieval, Brain and Language 28: 154-168.Google Scholar
  100. Wolf, M. & Goodman, G. (1996). Speed wizards. Computerized reading program. Tufts University and Rochester Institute of Technology.Google Scholar
  101. Wolf, M. & Miller, L. (1997). The Retrieval, Automaticity, Vocabulary Elaboration-Orthography (RAVE-O) reading intervention manual. An unpublished manual for NICHD grant No. 1R55HD/0D30970-O1A1.Google Scholar
  102. Wolf, M., Miller, L. & Donnelly, K. (2000). Retrieval, Automaticity, Vocabulary Elaboration-Orthography (RAVE-O): A comprehensive, fluency-based reading intervention program, Journal of Learning Disabilities 33: 375-386.Google Scholar
  103. Wolf, M. & Obregó n, M. (1992). Early naming deficits, developmental dyslexia, and a specific deficit hypothesis, Brain and Language 42: 219-247.Google Scholar
  104. Wolf, M., Pfeil, C., Lotz, R. & Biddle, K. (1994). Towards a more universal understanding of the developmental dyslexias: The contribution of orthographic factors. In: V.W. Berninger (ed.), The varieties of orthographic knowledge, Vol. I: Theoretical and developmental issues (pp. 137-171). Dordrecht/Boston/London: Kluwer Academic Publishers.Google Scholar
  105. Wolf, M. & Segal, D. (1999). Retrieval-rate, Accuracy, and Vocabulary Elaboration (RAVE) in reading-impaired children: A pilot intervention program, Dyslexia: An International Journal of Theory and Practice 5: 1-27.Google Scholar
  106. Wolff, P., Michel, C. & Ovrut, M. (1990a). Rate variables and automatized naming in developmental dyslexia, Brain and Language 39: 556-575.Google Scholar
  107. Wolff, P., Michel, C. & Ovrut, M. (1990b). The timing of syllable repetitions in developmental dyslexia, Journal of Speech and Hearing Research 33: 281-289.Google Scholar
  108. Wood, F.B. & Felton, RH. (1994). Separate linguistic and developmental factors in the development of reading, Topics in Language Disorders 14: 42-57.Google Scholar
  109. Woodcock, R.W. (1987). Woodcock Reading Mastery-Tests-Revised: Examiner's manual. Circle Pines, MN: American Guidance Service, Inc.Google Scholar
  110. Yap, R. & van der Leij, A. (1993). Word processing in dyslexics: An automatic decoding deficit?, Reading and Writing: An Interdisciplinary Journal 5: 261-279.Google Scholar
  111. Yap, R.L. & van der Leij, A. (1994). Testing the automatization deficit hypothesis of dyslexia via a dual-task paradigm, Journal of Learning Disabilities 27: 660-665.Google Scholar
  112. Young, A. & Bowers, P.G. (1995). Individual difference and text difficulty determinants of reading fluency and expressiveness, Journal of Experimental Child Psychology 60: 428-454.Google Scholar

Copyright information

© Kluwer Academic Publishers 2002

Authors and Affiliations

  • Maryanne Wolf
    • 1
    Email author
  • Alyssa Goldberg O'Rourke
    • 2
  • Calvin Gidney
    • 2
  • Maureen Lovett
    • 3
  • Paul Cirino
    • 4
  • Robin Morris
    • 4
  1. 1.Center for Reading and Language Research, Eliot-Pearson Department of Child DevelopmentTufts UniversityMedfordUSA
  2. 2.Tufts UniversityUSA
  3. 3.The Hospital for Slick Children and The University of TorontoCanada
  4. 4.Georgia State UniversityUSA

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