Abstract
In dieser Studie wurden die Prävalenzraten von Lernschwächen und Lernstörungen und hierbei auftretende Geschlechtsunterschiede in der Mitte der Grundschulzeit anhand einer großen deutschen Stichprobe (N = 2195) untersucht. Bei Lernschwächen und -störungen treten isolierte oder mehrfache Minderleistungen in den drei basalen schulischen Grundkompetenzen Lesen, Rechtschreiben und Rechnen trotz einer unbeeinträchtigten Intelligenz auf. Die Lernstörung wird hier als eine Untergruppe der Lernschwäche verstanden und liegt nach ICD-10 (WHO, 2005) dann vor, wenn neben der Leistungsabweichung von der Norm zusätzlich eine deutliche Diskrepanz zwischen der Minderleistung und der Intelligenz eines Kindes besteht (sogenanntes doppeltes Diskrepanzkriterium). Die Ergebnisse zeigen, dass insgesamt bei 23.3 % der Kinder eine Lernschwäche in einem oder mehreren Leistungsbereichen vorliegt. In etwa die Hälfte dieser Kinder verfehlt das zusätzliche Kriterium für eine Lernstörungsdiagnose. Betrachtet man die einzelnen Prävalenzraten für isolierte und multiple Lernschwierigkeiten im Lesen, Rechtschreiben und/oder Rechnen, liegen diese bei den Lernschwächen zwischen 4 und 6 % und bei den Lernstörungen zwischen 2 und 4 %. Deutlich mehr Jungen sind von Lese-Rechtschreib- und deutlich mehr Mädchen von Rechenschwierigkeiten betroffen. In bisher vorgelegten Prävalenzstudien wurden nicht alle basalen Schulleistungen berücksichtigt, sondern nur die jeweils diagnosespezifisch fokussierten Minderleistungen. Dadurch sind das Erkennen mehrfach lernbeeinträchtigter Kinder und eine eindeutige Diagnose nach ICD-10 nicht möglich. In der vorliegenden Studie zeigte sich eine Verdoppelung der Prävalenzraten durch das alleinige Berücksichtigen der diagnosespezifisch relevanten Leistungen. Die Befunde werden vor dem Hintergrund der praktischen Relevanz einer ICD-Diagnose und der Bedeutung einer umfassenden Schulleistungsdiagnostik diskutiert.
Background & Aims: In primary schools learning difficulties often occur in spite of an unimpaired intellectual ability. Experts differ substantively with regard to their appreciation of how many children are affected by these unexpected difficulties, which is also due to the divergent definitions of this phenomenon. On the one hand, the term “learning difficulties” is used to denominate poor learners whose results in basic scholastic achievement tests (reading, spelling, and/or calculating) are very low compared to same-aged peers. On the other hand, the term is used to indicate children with learning disorders and is thus taken as a clinical diagnosis classified in ICD10 (WHO, 2005). This classification defines that children with learning disorders do not only perform below average but also show a large discrepancy between their low achievement and their much higher intellectual ability. This IQ-achievement-discrepancy criterion is controversial because poor learners do not differ from children with learning disorders in terms of causal factors, socio-emotional consequences, and therapeutic responsiveness (e. g. Mähler et al., 2011). Despite these findings, in Germany practitioners usually distinguish between children with and without ICD-diagnosis: Scholastic remedy and public funding of interventions often depend on a diagnosed learning disorder. Therefore, the current study was designed to find out how many children are unexpected poor learners and how many of them do not fulfil the IQ-achievement-discrepancy criterion and are therefore often neglected by the educational system.
Another reason for different prevalence rate estimations is that most studies presented until now do not measure all basic scholastic achievements, and instead concentrate on the achievement of their interest. Under these circumstances further learning difficulties cannot be detected and in consequence distinct diagnoses are not possible. The amount of children with multiple learning difficulties is included into the prevalence rates of isolated learning difficulties. Therefore, the amount of children with isolated learning disorders might be overrated. To explore the extend of this overestimation, the prevalence rates of this study were estimated in two different ways: On the one hand, all three basic scholastic skills were included in the diagnostic process to distinguish isolated and multiple deficits accurately. On the other hand, only the scholastic achievement of diagnostic interest was considered (e. g. reading scores to identify children with reading disorder).
Methods: The reading, spelling, and calculating performances as well as the intellectual abilities of 2195 children (49.0 % girls) were assessed with standardized German achievement tests and a nonverbal IQ-test. During the assessment period the children were at the end of 2nd and the beginning of 3rd grade and on average 8;8 years (SD = 5 months) old. Since the group's sample statistics (means and deviations of achievement tests) differed slightly from the norm sample's statistics, all test norms were calculated anew on the basis of our sample. Thus, it is ensured that neither learning difficulties nor intellectual abilities are overestimated because of a deviation from the original test norms.
Results: The results show that 32.8 % of all children scored below average at least in one achievement domain, scoring more than one standard deviation below the sample's mean. Altogether there were 23.3 % unexpected poor learners who failed despite having an unimpaired intellectual ability. However, 43 % of these poor learners did not fulfil the IQ-achievement-discrepancy criterion. Of all children 13.3 % were affected by a learning disorder. Taking a closer look at the separate scholastic achievements, 4 to 6 % of the children were identified as poor learners and 2 to 4 % were identified as having learning disorders in a single scholastic achievement (reading, spelling, or calculating) or in multiple achievements (reading and spelling or in at least one literacy competence and calculating). Results also show that boys were twice as likely as girls to suffer from literacy difficulties, whereas girls were three times as frequently as boys affected by calculating difficulties. Few more girls were affected by combined learning difficulties in literacy and calculating, while combined learning disorders were equally frequent in boys and girls.
In view of the fact that usually in prevalence studies only the scholastic achievement of interest but not all three basic achievements are assessed, we examined the influence of restricted compared to comprehensive diagnostics. The results show that under restricted diagnostic conditions, the prevalence rates doubled (in spite of reading and spelling disorder that is less increased).
Discussion: A serious amount, namely around one third of all primary school children in Germany, seems to have difficulties in basic scholastic achievements. Around one quarter of all children have these difficulties despite an unimpaired intellectual disability. Even given their unimpaired intellectual abilities almost half of them do not reach the strict IQ-achievement-discrepancy criterion. While in the field this controversial criterion is nowadays less frequently applied, in Germany the educational and health system continue to be influenced by the application of an ICD-10 diagnosis. Besides the enduring scientific debate on the sense of the IQ-achievement-discrepancy and the intention to change the ICD-criteria for learning disorders, practitioners should find a way of including all children with unexpected learning difficulties in special interventions.
The prevalence rates and sex distributions for poor learners and children with learning disorders reported in the present study are in the range of former research, albeit at the lower end. The less frequent incidence of unexpected learning difficulties is caused by comprehensive diagnostics of basic scholastic achievements. Taking only the achievement of diagnostic interest into account doubles prevalence rates. Hence, in research as well as in individual diagnostics it is very important to rule out further learning difficulties with broad assessments.
Literatur
(1983). Dyscalculia and nonverbal disorders of learning. In H. R. Myklebust (Ed.), Progress in learning disabilities (pp. 235 – 264). New York: Grune & Stratton.
(2005). Math learning disorder: Incidence in a population-based birth cohort, 1976 – 1982, Rochester, Minn. Ambulatory Pediatrics , 5, 281 – 289.
(2007). Weingartener Grundwortschatz Rechtschreib-Test für 2. und 3. Klassen (WRT 2+). Göttingen: Hogrefe.
(Hrsg.). (2008). TIMSS 2007. Mathematische und naturwissenschaftliche Kompetenzen von Grundschulkindern in Deutschland im internationalen Vergleich. Münster: Waxmann.
et al. (Hrsg.). (2007). IGLU 2006. Lesekompetenzen von Grundschulkindern in Deutschland im internationalen Vergleich. Münster: Waxmann.
(1990). A review of recent research on spelling. Educational Psychology Review , 2, 365 – 397.
(2011). Learning disabilities: Debates on definitions, causes, subtypes, and responses. International Journal of Disability, Development, and Education , 58, 75 – 87.
(1997). Culture Fair Test – Grundintelligenztest Skala 1 (CFT 1). Göttingen: Hogrefe.
(2004). Children with mathematics learning disabilities in Belgium. Journal of Learning Disabilities , 37, 50 – 61.
(2008). Prevalence of combined reading and arithmetic disabilities. Journal of Learning Disabilities , 41, 460 – 473.
(2010). Zeigen Kinder mit schulischen Minderleistungen sozio-emotionale Auffälligkeiten? Zeitschrift für Entwicklungspsychologie und Pädagogische Psychologie , 42, 201 – 210.
(1987). Massive IQ gains in 14 nations: What IQ tests really measure. Psychological Bulletin , 101, 171 – 191.
(1996). Developmental dyscalculia: Prevalence and demographic features. Developmental Medicine and Child Neurology , 38, 25 – 33.
(2006). Längsschnittliche Analysen zur Lese-, Rechtschreib- und Mathematikleistung im Grundschulalter: Zur Rolle von Vorwissen, Intelligenz, phonologischem Arbeitsgedächtnis und phonologischer Bewusstheit. In I. Hosenfeld & F.-W. Schrader (Hrsg.), Schulische Leistung: Grundlagen, Bedingungen, Perspektiven (S. 87 – 105). Münster: Waxmann.
(2006). Epidemiologie Lernstörungen. Kindheit und Entwicklung , 15, 208 – 215.
(2000). The specific disorder of arithmetic skills. Prevalence studies in a rural and an urban population sample and their clinic-neuropsychological validation. European Child and Adolescent Psychiatry , 9, 87 – 101.
(2003). The relationship between IQ and reading disabilities in English-speaking Canadian and Spanish children. Journal of Learning Disabilities , 36, 15 – 23.
(2010). The impact of the Flynn effect on LD diagnoses in special education. Journal of Learning Disabilities , 45, 319 – 326.
(2004). Deutscher Mathematiktest für zweite Klassen (DEMAT 2+). Göttingen: Hogrefe.
(2010). Comorbidity of learning disorders: prevalence and familial transmission. Journal of Child Psychology and Psychiatry , 51, 287 – 294.
(2006). Ein Leseverständnistest für Erst- bis Sechstklässler (ELFE 1 – 6). Göttingen: Hogrefe.
(1994). The prevalence of specific arithmetic difficulties and specific reading difficulties in 9- to 10-year-old boys and girls. Journal of Child Psychology and Psychiatry , 25, 283 – 292.
(2005). Male vulnerability to reading disability is not likely to be a myth: A call for new data. Journal of Learning Disabilties , 38, 109 – 129.
(2005). Orthographische Kompetenzen: Ergebnisse qualitativer Fehleranalysen, insbesondere bei schwachen Rechtschreibern. In W. Bos, E.-M. Lankes, M. Prenzel, K. Schwippert, R. Valtin & G. Walther (Hrsg.), IGLU. Vertiefende Analysen zu Leseverständnis, Rahmenbedingungen und Zusatzstudien (S. 81 – 108). Münster: Waxmann.
(2011). Working memory in children with learning disabilities: Rethinking the criterion of discrepancy. International Journal of Disability, Development and Education , 58, 5 – 17.
(2001). Legasthenie versus allgemeine Lese-Rechtschreibschwäche: Ein Vergleich der Leistungen in der phonologischen und visuellen Informationsverarbeitung. Zeitschrift für Pädagogische Psychologie , 15, 85 – 98.
(2009). Double dissociation between reading and spelling deficits. Scientific Studies of Reading , 13, 359 – 382.
(2012). Die Anfänge geschlechtsspezifischer Leistungsunterschiede in mathematischen und schriftsprachlichen Kompetenzen. Zeitschrift für Entwicklungspsychologie und Pädagogische Psychologie , 44, 123 – 138.
et al., (2012). Basic Numerical Capacities and Prevalence of Developmental Dyscalculia: The Havana Survey. Developmental Psychology , 48, 123 – 135.
(2008). Entwicklung und Erfassung der Rechtschreibkompetenz im Jugend- und Erwachsenenalter. In W. Schneider, H. Marx & M. Hasselhorn (Hrsg.), Diagnostik von Rechtschreibleistungen und -kompetenz (Tests und Trends, N. F., Band 6, S. 145 – 157). Göttingen: Hogrefe.
(1989). IQ is irrelevant to the definition of learning disabilities. Journal of Learning Disabilities , 22, 469 – 478.
(2003). IQ-discrepancy definitions and the diagnosis of LD: Introduction to the special issue. Journal of Learning Disabilities , 36, 2 – 3.
(2002). Validity of IQ-discrepancy classifications of reading disabilities: A meta-analysis. American Educational Research Journal , 39, 469 – 518.
(2004). Mathematische Kompetenzen am Ende der vierten Jahrgangsstufe in einigen Ländern der Bundesrepublik Deutschland. In W. Bos, E.-M. Lankes, M. Prenzel, K. Schwippert, R. Valtin & G. Walther (Hrsg.), IGLU. Einige Länder der Bundesrepublik Deutschland im nationalen und internationalen Vergleich (S. 117 – 140). Münster: Waxmann.
(2002). Profitieren Legastheniker und allgemein lese-rechtschreibschwache Kinder in unterschiedlichem Ausmaß von einem Rechtschreibtraining? Psychologie in Erziehung und Unterricht , 49, 56 – 70.
(2009). Sind Rechenstörungen genau so häufig wie Lese-Rechtschreibstörungen? Zeitschrift für Kinder- und Jugendpsychiatrie und Psychotherapie , 37, 499 – 512.
. (2005). ICD: Classification of mental and behavioural disorders: Clinical descriptions and diagnostic guidelines (10th rev. ed.). Geneva, Switzerland: Author.
