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Revisiting Discrepancy Theory in Learning Disabilities: What Went Wrong and Why We Should Go Back

Published online by Cambridge University Press:  16 November 2012

Sarah Callinan ,
Everarda Cunningham  and
Stephen Theiler
Sarah Callinan*
Affiliation:
Swinburne University of Technology, Australia
Everarda Cunningham
Affiliation:
Swinburne University of Technology, Australia
Stephen Theiler
Affiliation:
Swinburne University of Technology, Australia
*
address for correspondence: Dr Sarah Callinan, Faculty of Higher Education, Swinburne University of Technology, Lilydale VIC 3140, Australia. Email: [email protected]
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Abstract

The rise in popularity of Response to Intervention (RTI) as a method of identifying Learning Disabilities (LD) is partially due to the psychometric and theoretical issues inherent to the use of IQ tests in the once popular discrepancy method of identification. However, both RTI and discrepancy theories have their shortcomings, and criticisms directed at either method are usually applicable to both. This conceptual article puts forward a justification for using tests of the cognitive processes that are implicated in LD as a better method of LD identification. Although the unsuitability of the discrepancy method to accurately identify LD students is well established, it does represent the construct of LD well. Therefore, the discrepancy method can be used as an effective baseline measure against which improved identification procedures based on cognitive processes can be measured. Once these cognitive processes are more clearly defined, tests of these processes offer promise for LD identification.

Keywords

learning disabilitiesdiscrepancyresponse to interventioncognitive deficits
Type
Articles
Information
Journal of Psychologists and Counsellors in Schools , Volume 23 , Issue 1 , June 2013 , pp. 1 - 17
Copyright
Copyright © The Authors 2012

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References

Altarac, M., & Saroha, E. (2007). Lifetime prevalence of learning disability among US children. Pediatrics, 119, S77. doi:10.1542/peds.2006–2089CrossRefGoogle ScholarPubMed
Anastasiou, D., & Polychronopoulou, S. (2009). Identification and overidentification of specific learning disabilities (dyslexia) in Greece. Learning Disability Quarterly, 32, 55–69.CrossRefGoogle Scholar
Andreassen, A.E., Knivsberg, A.M., & Niemi, P. (2006). Resistant readers 8 months later: Energizing the student's learning milieu by targeted counselling. Dyslexia, 12, 115–133.CrossRefGoogle ScholarPubMed
Baddeley, A.D. (1986). Working memory. Oxford: Oxford University Press.Google ScholarPubMed
Barnes, M.A., & Wade-Woolley, L. (2007). Where there's a will there are ways to close the achievement gap for children with learning difficulties. Orbit, 37 (1), 9–13.Google Scholar
Bekebrede, J., van der Leij, A., & Share, D.L. (2009). Dutch dyslexic adolescents: Phonological-core variable-orthographic differences. Reading and Writing, 22, 133–165.CrossRefGoogle Scholar
Berkeley, S., Bender, W.N., Peaster, L.G., & Saunders, L. (2009). Implementation of response to intervention: A snapshot of progress. Journal of Learning Disabilities, 42 (1), 85–95.CrossRefGoogle ScholarPubMed
Berninger, V.W., & Holdnack, J.A. (2008). Nature-nurture perspectives in diagnosing and treating learning disabilities: Response to questions begging answers that see the forest and the trees. In Fletcher-Janzen, E. & Reynolds, C.R. (Eds.), Neuropsychological perspectives on learning disabilities in the era of RTI (pp. 66–81). Hoboken, NY: John Wiley & SonsGoogle Scholar
Berninger, V.W., Raskind, W., Richards, T., Abbott, R., & Stock, P. (2008). A multidisciplinary approach to understanding developmental dyslexia within working-memory architecture: Genotypes, phenotypes, brain, and instruction. Developmental Neuropsychology, 33 (6), 707–744.CrossRefGoogle ScholarPubMed
Cahan, S., Fono, D., & Nirel, R. (2010). The regression-based discrepancy definition of learning disability: A critical appraisal, Journal of Learning Disabilities 45 (2), 170–178. doi:10.1177/0022219409355480CrossRefGoogle ScholarPubMed
Cao, F., Bitan, T., & Booth, J.R. (2008). Effective brain connectivity in children with reading difficulties during phonological processing. Brain & Language, 107, 91–101.CrossRefGoogle ScholarPubMed
Caylak, E. (2010). The studies about phonological deficit theory in children with developmental dyslexia: Review. American Journal of Neuroscience, 6, 1–12.Google Scholar
Chung, K.K.H., & Ho, C. S.-H. (2010). Second language learning difficulties in Chinese children with dyslexia: What are the reading-related cognitive skills that contribute to English and Chinese word reading? Journal of Learning Disabilities, 43, 195–211.CrossRefGoogle ScholarPubMed
Cone, T., & Wilson, L. (1981). Quantifying a severe discrepancy: A critical analysis. Learning Disability Quarterly, 4, 359–371.CrossRefGoogle Scholar
Cotton, S.M., Crewther, D.P., & Crewther, S.G. (2005). Measurement error: Implications for diagnosis and discrepancy models of developmental dyslexia. Dyslexia, 11 (3): 186–202.CrossRefGoogle ScholarPubMed
Coutinho, M.J., Oswald, D.P., & Best, A.M. (2002). The influence of sociodemographics and gender on the disproportionate identification of minority students as having learning disabilities. Remedial & Special Education, 23 (1), 49–59. doi:10.1177/074193250202300107CrossRefGoogle Scholar
Davis-Kean, P.E. (2005). The influence of parent education and family income on child achievement: The indirect role of parental expectations and the home environment. Journal of Family Psychology, 19, 294–304.CrossRefGoogle ScholarPubMed
Desroches, A., Cone, N.E., Bolger, D.J., Bitan, T., Burman, D.D., & Booth, J.R. (2010). Children with reading difficulties show differences in brain regions associated with orthographic processing during spoken language processing. Brain Research, 1356, 73–84. doi:10.1016/j.brainres.2010.07.097.CrossRefGoogle ScholarPubMed
Dombrowski, S.C., Kamphaus, R.W., & Reynolds, C.R. (2004). After the demise of the discrepancy: Proposed learning disabilities diagnostic criteria. Professional Psychology: Research and Practice, 35 (4), 364–372.CrossRefGoogle Scholar
Elliott, J., & Gibbs, S. (2008). Does dyslexia exist? Journal of Philosophy of Education, 42 (3–4), 475–491.CrossRefGoogle Scholar
Fan, X., & Chen, M. (2001). Parental involvement and students’ academic achievement: A meta-analysis. Educational Psychology Review, 13 (1), 1–22.CrossRefGoogle Scholar
Fletcher, J.M., Coulter, W.A., Reschly, D.J., & Vaughn, S. (2004). Alternative approaches to the definition and identification of learning disabilities: Some questions and answers. Annals of Dyslexia, 54 (2), 304–331. doi:10.1007/s11881-004-0015-yCrossRefGoogle Scholar
Fletcher, J.M., & Vaughn, S. (2009). Response to intervention models as alternatives to traditional views of learning disabilities: Response to commentaries. Child Development Perspectives, 3 (1), 48–50.CrossRefGoogle ScholarPubMed
Francis, D.J., Fletcher, J.M., Stuebing, K.K., Lyon, G.R., Shaywitz, B.A., & Shaywitz, S.E. (2005). Psychometric approaches to the identification of LD: IQ and achievement scores are not sufficient. Journal of Learning Disabilities, 38 (2), 98–108.CrossRefGoogle Scholar
Frijters, J.C., Lovett, M.W., Steinbach, K.A., Wolf, M., Sevcik, R.A., & Morris, R.D. (2011). Neurocognitive predictors of reading outcomes for children with reading disabilities. Journal of Learning Disabilities, 44, 150. doi:10.1177/0022219410391185.CrossRefGoogle ScholarPubMed
Fuchs, D., & Fuchs, L.S. (2006). Introduction to response to intervention: What, why, and how valid is it? Reading Research Quarterly, 41 (1), 92–99.CrossRefGoogle Scholar
Fuchs, D., Fuchs, L.S., Compton, D.L., Bouton, B., Caffrey, E., & Hill, L. (2007). Dynamic assessment as responsiveness to intervention. Teaching Exceptional Children, 39 (5), 58–63.CrossRefGoogle Scholar
Fuchs, L.S., Fuchs, D., & Hollenbeck, K.N. (2007). Extending responsiveness to intervention to mathematics at First and Third Grades. Learning Disabilities Research & Practice, 22 (1), 13–24.CrossRefGoogle Scholar
Gathercole, S.E., Briscoe, J., Thorn, A., Tiffany, C., & Team, A.S. (2008). Deficits in verbal long-term memory and learning in children with poor phonological short-term memory skills. Quarterly Journal of Experimental Psychology, 61 (3), 474–490.CrossRefGoogle ScholarPubMed
Georgiou, G.K., Parilla, R. & Liao, C.H. (2008). Rapid naming speed and reading across languages that vary in orthographic consistency. Reading and Writing, 21, 885–903.CrossRefGoogle Scholar
Grigorenko, E.L. (2001). Developmental dyslexia: An update on genes, brains and environments. Journal of Child Psychology and Psychiatry, 42 (1), 91–125.CrossRefGoogle ScholarPubMed
Grigorenko, E.L. (2009). Dynamic assessment and response to intervention: Two sides of one coin. Journal of Learning Disabilities, 42 (2), 111–132.CrossRefGoogle ScholarPubMed
Gustafson, S., & Samuelsson, S. (1999). Intelligence and dyslexia: Implications for diagnosis and intervention. Scandinavian Journal of Psychology, 40 (2), 127–134.Google ScholarPubMed
Hamalainen, J.A., Leppanen, P., Eklund, K., Thomson, J.B., Richardson, U., Guttorm, T. K., . . . Lyttinen, H. (2009). Common variance in amplitude envelope perception tasks and their impact on phoneme duration perception and reading and spelling in Finnish children with reading disabilities. Applied Psycholinguistics, 30, 511–530.CrossRefGoogle Scholar
Hirvonen, R., Georgiou, G., Lerkkanen, M., Aunola, K., & Nurmi, J. (2010). Task-focused behaviour and literacy development: A reciprocal relationship. Journal of Research in Reading, 33 (3), 302–319.CrossRefGoogle Scholar
Hiscock, M., & Kindsbourne, M. (2008). The education empire strikes back: Will RTI displace neuropsychology and neuroscience from the realm of learning disabilities. In Fletcher-Janzen, E. & Reynolds, C.R. (Eds.), Neuropsychological perspectives on learning disabilities in the era of RTI (pp. 54–65). Hoboken, NY: John Wiley & Sons.Google Scholar
Ho, C.S.-H., Chan, D.W.O., Lee, S.H., Tsang, S.M., & Luan, V.H. (2004). Cognitive profiling and preliminary sub typing in Chinese developmental dyslexia. Cognition, 91 (1), 43–75.CrossRefGoogle Scholar
Holdnack, J.A., & Weiss, L.G. (2006). Idea 2004: Anticipated implications for clinical practice-integrating assessment and intervention. Psychology in the Schools, 43 (8), 871–882.CrossRefGoogle Scholar
Hudson, R.F., High, L., & Otaiba, S.A.L. (2007). Dyslexia and the brain: What does current research tell us? Reading Teacher, 60 (6), 506–513.CrossRefGoogle Scholar
Ingvar, M., af Trampe, P., Greitz, T., Eriksson, L., Stone-Elander, S., & von Euler, C. (2002). Residual differences in language processing in compensated dyslexics revealed in simple word reading tasks. Brain & Language, 83, 249–267.CrossRefGoogle ScholarPubMed
Jeffries, S., & Everatt, J. (2004). Working memory: Its role in dyslexia and other specific learning difficulties. Dyslexia, 10, 196–214.CrossRefGoogle ScholarPubMed
Johnston, R.S., & Morrison, M. (2007). Toward a resolution of inconsistencies in the phonological deficit theory of reading disorders: Phonological reading difficulties are more severe in high-IQ poor readers. Journal of Learning Disabilities, 40 (1), 66–79.CrossRefGoogle Scholar
Kane, M.T. (2001). Current concerns in validity theory. Journal of Educational Measurement, 38 (4), 319–342.CrossRefGoogle Scholar
Katzir, T., Kim, Y.S., Wolf, M., Morris, R., & Lovett, M.W. (2008). The varieties of pathways to dysfluent reading: Comparing subtypes of children with dyslexia at letter, word, and connected text levels of reading. Journal of Learning Disabilities, 41, 47–66. doi:10.1177/0022219407311325CrossRefGoogle ScholarPubMed
Kirby, J.R., Georgiou, G., Martinussen, R., & Parrila, R. (2010). Naming speed and reading: From prediction to instruction. Reading Research Quarterly, 45 (3), 341–362.CrossRefGoogle Scholar
Laasonen, M., Oinonen, S., Sandbacka, M., Salakari, A., & Service, E. (2012). Phonological and sensory short-term memory are correlates and both affected in developmental dyslexia. Reading and Writing, 25 (9), 2247–2273.CrossRefGoogle Scholar
Linklater, D.L., O'Connor, R., & Palardy, G.J. (2009). Kindergarten literacy assessment of English only and English language learner students: An examination of the predictive validity of three phonemic awareness measures. Journal of School Psychology, 47, 369–394.CrossRefGoogle ScholarPubMed
Linver, M.R., Brooks-Gunn, J., & Kohen, D. (2002). Family processes as pathways from income to young children's development. Developmental Psychology, 38, 719–734.CrossRefGoogle ScholarPubMed
Lukanenok, K. (2011). Relationship between rapid naming speed and reading speed as a marker of reading difficulties of Estonian children from 6 to 8 years. Journal of Teacher Education for Sustainability, 13 (1), 113–128. doi: 10.2478/v10099-011-0009-xCrossRefGoogle Scholar
Machek, G.R., & Nelson, J.M. (2007). How should reading disabilities be operationalized? A survey of practicing school psychologists. Learning Disabilities Research & Practice, 22 (2), 147–157. doi:10.1111/j.1540-5826.2007.00239.xCrossRefGoogle Scholar
Marder, C., & D'Amico, R. (1992). How well are youth with disabilities really doing? A comparison of youth with disabilities and youth in general. Washington, DC: Department of Education Office of Special Education Programs.Google Scholar
Mather, N., & Schrank, F.A. (2001). Use of the WJ III Discrepancy Procedures for Learning Disabilities Identification and Diagnosis (Woodcock-Johnson III Assessment Service Bulletin No. 3). Itasca, IL: Riverside PublishingGoogle Scholar
McLeod, J. (1979). Educational under-achievement: Toward a defensible psychometric definition. Journal of Learning Disabilities, 12, 42–50.CrossRefGoogle Scholar
McNamara, J.K. & Willoughby, T. (2010). A longitudinal study of risk-taking behavior in adolescents with learning disabilities. Learning Disabilities Research & Practice, 25 (1), 11–24. doi:10.1111/j.1540-5826.2009.00297.xCrossRefGoogle Scholar
Metsala, J.L., Sweet, A.P., & Guthrie, J.T. (1996). How children's motivations relate to literacy development and instruction. The Reading Teacher, 49 (8), 660–662.Google Scholar
Nicolson, R.I. (1996). Developmental dyslexia: Past, present and future. Dyslexia, 2, 190–207.3.0.CO;2-6>CrossRefGoogle Scholar
O'Donnell, P.S., & Miller, D.M. (2011). Identifying students with specific learning disabilities: School psychologists’ acceptability of the discrepancy model versus response to intervention. Journal of Disability Policy Studies, 22 (2)83–94. doi:10.117/1044207310395724CrossRefGoogle Scholar
O'Shaughnessy, T.E., & Swanson, H.L. (1998). Do immediate memory deficits in students with learning disabilities in reading reflect a developmental lag or deficit?: A selective meta-analysis of the literature. Learning Disability Quarterly, 21 (2), 123–148.CrossRefGoogle Scholar
Reschly, D.J., & Hosp, J.L. (2004). State SLD identification policies and practices. Learning Disability Quarterly, 27 (4), 197–213.CrossRefGoogle Scholar
Reynolds, C.R. (1984). Critical measurement issues in learning disabilities. Journal of Special Education, 18 (4), 451–476.CrossRefGoogle Scholar
Reynolds, C.R. (2008). RTI, neuroscience, and sense: Chaos in the diagnosis and treatment of learning disabilities. In Fletcher-Janzen, E. & Reynolds, C.R. (Eds.), Neuropsychological perspectives on learning disabilities in the era of RTI (pp. 14–27). Hoboken, NY: John Wiley & Sons.Google Scholar
Reynolds, C.R., & Shaywitz, S.E. (2009). Response to intervention: Prevention and remediation, perhaps. Diagnosis, no. Child Development Perspectives, 3 (1), 44–47.CrossRefGoogle ScholarPubMed
Riccio, C.A. (2008). Compatability of neuropsychology and RTI in the diagnosis and assessment of learning disabilities. In Fletcher-Janzen, E. & Reynolds, C.R. (Eds.), Neuropsychological perspectives on learning disabilities in the era of RTI (pp. 82–98). Hoboken, NY: John Wiley & Sons.Google Scholar
Richards, T.L., & Berninger, V.W. (2008). Abnormal fMRI connectivity in children with dyslexia during a phoneme task: Before but not after treatment. Journal of Neurolinguistics, 21, 294–308.CrossRefGoogle Scholar
Roberts, J.E., Rabinowitch, S., Bryant, D. M., Burchinal, M.R., Koch, M.A., & Ramey, C. (1989). Language skills of children with different preschool experiences. Journal of Speech and Hearing Research, 32, 773–786.CrossRefGoogle ScholarPubMed
Rutter, M., & Yule, W. (1975). The concept of specific reading retardation. Journal of Child Psychology and Psychiatry, 16 (3), 181–197.CrossRefGoogle ScholarPubMed
Savage, R., & Frederickson, N. (2006). Beyond phonology: What else is needed to describe the problems of below-average readers and spellers? Journal of Learning Disabilities, 39 (5), 399–413.CrossRefGoogle ScholarPubMed
Schiff, R., & Raveh, M. (2006). Deficient morphological processing in adults with developmental dyslexia: Another barrier to efficient word recognition? Dyslexia, 13, 110–129.CrossRefGoogle Scholar
Schuchardt, K., Maehler, C., & Hasselhorn, M. (2008). Working memory deficits in children with specific learning disorders. Journal of Learning Disabilities, 41, 514. doi:10.1177/0022219408317856CrossRefGoogle ScholarPubMed
Scruggs, T.E., & Mastropieri, M.A. (2002). On babies and bathwater: Addressing the problems of identification of learning disabilities. Learning Disability Quarterly, 25 (3), 155.CrossRefGoogle Scholar
Shaywitz, S.E., & Shaywitz, B.A. (2004). Reading disability and the brain. Educational Leadership, 61 (6), 6–11.Google Scholar
Siegel, L.S., & Ryan, E.B. (1989). The development of working memory in normally achieving and subtypes of learning disabled students. Child Development, 60, 973–980.CrossRefGoogle Scholar
Silver, C.H., Ruff, R.M., Iverson, G.L., Barth, J.T., Broshek, D.K., . . . Reynolds, C.R. (2008). Learning disabilities: The need for neuropsychological evaluation. Archives of Clinical Neuropsychology, 23 (2), 217–219.CrossRefGoogle ScholarPubMed
Snowling, M.J. (1980). The development of grapheme-phoneme correspondence in normal and dyslexic readers. Journal of Experimental Child Psychology, 29 (2), 294–305.CrossRefGoogle ScholarPubMed
Spagna, M.E. (1998). Dyslexia marker variables: Reviving a system for reporting sample characteristics in learning disabilities research. Remedial and Special Education, 19 (5), 291–299.CrossRefGoogle Scholar
Speece, D.L. (2008). Learning disabilities in the USA: Operationalising a construct. In Florian, L. & McLaughlin, M.J. (Eds.), Disability classfication in education: Issues and perspectives (pp. 69–82). Thousand Oaks, CA: Corwin Press.Google Scholar
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), 24–53CrossRefGoogle Scholar
Sternberg, R.J., & Grigorenko, E.L. (2002). Difference scores in the identification of children with learning disabilities it's time to use a different method. Journal of School Psychology, 40 (1), 65–83.CrossRefGoogle Scholar
Stoodley, C.J., Ray, N.J., Jack, A., & Stein, J.F. (2008). Implicit learning in control, dyslexic, and garden-variety poor readers, Annals of the New York Academy of Sciences, 1145, 173–183.CrossRefGoogle ScholarPubMed
Stuebing, K.K., Fletcher, J.M., LeDoux, J.M., Reid Lyon, G., Shaywitz, S.E., & Shaywitz, B.A. (2002). Validity of IQ-discrepancy classifications of reading disabilities: A meta analysis. American Educational Research Journal, 39, 469. doi:10.3102/00028312039002469CrossRefGoogle Scholar
Swanson, H.L., Zheng, X., & Jerman, O. (2009). Working memory, short term memory, and reading disabilities: A selective meta-analysis of the literature. Journal of Learning Disabilities, 42 (3), 260–287.CrossRefGoogle ScholarPubMed
Tanaka, H., Black, J. M., Hulme, C., Stanley, L.M., Kesler, S.R., . . . Hoeft, F. (2011). The brain basis of the phonological deficit in dyslexia is independent of IQ. Psychological Science, 22 (11), 1442. doi: 10.1177/0956797611419521CrossRefGoogle ScholarPubMed
Taylor, M.J., & Barusch, A.S. (2004). Personal, family, and multiple barriers of long term welfare recipients. Social Work, 49 (2), 175–183.CrossRefGoogle ScholarPubMed
Torppa, M., Lyytinen, P., Erskine, J., Eklund, K., & Lyytinen, H. (2010). Language development, literacy skills, and predictive connections to reading in Finnish children with and without familial risk for dyslexia. Journal of Learning Disabilities, 43 (4), 308–321.CrossRefGoogle ScholarPubMed
Van den Broeck, W. (2002). Will the real discrepant learning disability please stand up? Journal of Learning Disabilities, 35 (3), 209–213CrossRefGoogle ScholarPubMed
Van Der Heyden, A.M. (2011). Evolving standards of diagnostic accuracy in predicting and avoiding academic failure. Advances in Learning and Behavioural Disabilities, 24, 59–78. doi:10.1108/S0735-004X(2011)0000024005CrossRefGoogle Scholar
van der Lely, H.K.J., & Marshall, C.R. (2010). Assessing component language deficits in the early detection of reading difficulty risk. Journal of Learning Disabilities, 43 (4), 357–368.CrossRefGoogle ScholarPubMed
Volker, M.A., Lopata, C., & Cook-Cottone, C. (2006). Assessment of children with intellectual giftedness and reading disabilities. Psychology in the Schools, 43 (8), 855–869.CrossRefGoogle Scholar
Willburger, E., Fussenegger, B., Moll, K., Wood, G., & Landerl, K. (2008). Naming speed in dyslexia and dyscalculia. Learning and Individual Differences, 18, 224–236.CrossRefGoogle Scholar
Willis, J.O., & Dumont, R. (2006). And never the twain shall meet: Can response to intervention and cognitive assessment be reconciled? Psychology in the Schools, 43 (8), 901–908.CrossRefGoogle Scholar
Willson, V.L., & Reynolds, C.R. (2002). Misconceptions in Van den Broeck's representation of misconceptions about learning disability research. Journal of Learning Disabilities, 35 (3), 205–208.CrossRefGoogle Scholar
Wolf, M., & Bowers, P.G. (1999). The double-deficit hypothesis for the developmental dyslexias. Journal of Educational Psychology, 91 (3), 415–438.CrossRefGoogle Scholar
Wong, S.W.L., & Ho, C.S.-H. (2010). The nature of the automatization deficit in Chinese children with dyslexia. Child Neuropsychology, 16, 405–415.CrossRefGoogle ScholarPubMed
Woolley, G. (2007). A comprehension intervention for children with reading comprehension difficulties. Australian Journal of Learning Disabilities, 12 (1), 43–50.CrossRefGoogle Scholar
Zabel, R.J., & Nigro, F.A. (1999). Juvenile offenders with behavioural disorders, learning disabilities, and no disabilities: Self-reports of personal, family, and school characteristics. Behavioural Disorders, 25 (1), 22–40.CrossRefGoogle Scholar
Zeffiro, T., & Eden, G. (2000). The neural basis of developmental dyslexia. Annals of Dyslexia, 50, 3–30CrossRefGoogle ScholarPubMed