Intervention for Dyslexia A review of published evidence on the impact of specialist dyslexia teaching Chris Singleton University of Hull May 2009 © Copyright Chris Singleton and ‘No To Failure’ 2009 2 Intervention for Dyslexia Contents EXECUTIVE SUMMARY .........................................................................................6 ACKNOWLEDGEMENTS ........................................................................................................ 13 1 INTRODUCTION ............................................................................................................... 14 1.1 AIMS AND SCOPE............................................................................................................ 14 1.1.1 Remit...................................................................................................................... 14 1.1.2 Limitations............................................................................................................. 14 1.1.3 The author.............................................................................................................. 15 1.2 DEFINITIONS OF DYSLEXIA ............................................................................................ 16 1.2.1 United Kingdom..................................................................................................... 16 1.2.2 United States of America ....................................................................................... 17 1.3 WHAT IS ‘SPECIALIST DYSLEXIA TEACHING’?............................................................... 18 1.3.1 The nature of the problem...................................................................................... 18 1.3.2 Historical overview................................................................................................ 18 1.3.3 Current perspectives on specialist dyslexia teaching ............................................ 18 1.3.4 Conclusions ........................................................................................................... 21 1.3.5 Wider roles of the specialist dyslexia teacher ....................................................... 22 1.4 VISUAL STRESS AND DYSLEXIA ..................................................................................... 23 1.4.1 Visual dyslexia?..................................................................................................... 23 1.4.2 The implications of visual stress for reading development.................................... 24 1.4.3 Relationship between visual stress and dyslexia ................................................... 24 1.5 METHODS AND MEASURES............................................................................................. 26 1.5.1 Methodology .......................................................................................................... 26 1.5.2 Standard scores ..................................................................................................... 26 1.5.3 Effect size............................................................................................................... 27 1.5.4 Ratio gain .............................................................................................................. 27 1.6 STRUCTURE OF THE REVIEW .......................................................................................... 28 2 INTERVENTION STUDIES IN THE US AND THE REST OF THE WORLD .......... 29 2.1 STAGES OF INTERVENTION IN THE USA ........................................................................ 29 2.2 SECONDARY INTERVENTION STUDIES............................................................................ 29 2.2.1 Swanson’s (1999) meta-analysis ........................................................................... 30 2.2.2 Vellutino, Scanlon, Sipay et al. (1996) .................................................................. 30 2.2.3 Torgesen et al. (1999)............................................................................................ 31 2.2.4 Scammacca et al. (2007) review............................................................................ 32 2.2.5 Foorman et al. (1997)............................................................................................ 33 2.2.6 Schneider, Roth and Ennemoser (2000) ................................................................ 33 2.2.7 Vadasy et al. (2002)............................................................................................... 34 2.2.8 Mathes et al. (2005)............................................................................................... 34 2.2.9 Ryder, Tunmer and Greaney (2008)...................................................................... 35 2.2.10 Frost & Sørensen (2007) ....................................................................................... 36 2.2.11 Vaughn and Roberts (2007) review ....................................................................... 36 2.3 CRITICAL ISSUES IN SECONDARY INTERVENTION .......................................................... 37 2.3.1 Long-term effects ................................................................................................... 37 2.3.2 Who should deliver intervention: teachers or teaching assistants? ...................... 38 2.4 CONCLUSIONS ON SECONDARY INTERVENTION............................................................. 39 2.5 TERTIARY INTERVENTION STUDIES ............................................................................... 40 2.5.1 Torgesen, Alexander et al. (2001) ......................................................................... 40 Intervention for Dyslexia 3 2.5.2 Rashotte, McPhee and Torgesen (2001) ................................................................42 2.5.3 Reviews and analyses by Torgesen (2005a & 2005b)............................................43 2.5.4 Alexander et al. (1991)...........................................................................................44 2.5.5 Lovett et al. (1994) .................................................................................................45 2.5.6 Wise, Ring and Olson (1999)..................................................................................45 2.5.7 Lovett et al. (2000) .................................................................................................45 2.5.8 O’Connor and Wilson (1995).................................................................................45 2.5.9 Torgesen et al. (2003) ............................................................................................45 2.5.10 Torgesen et al. (2004) ............................................................................................47 2.6 FLUENCY ........................................................................................................................47 2.7 SPELLING ........................................................................................................................48 2.8 WRITING .........................................................................................................................49 2.9 CRITICAL ISSUES IN TERTIARY INTERVENTION...............................................................50 2.9.1 Number of hours of intervention.............................................................................50 2.9.2 Degree of impairment.............................................................................................51 2.9.3 Group size...............................................................................................................51 2.9.4 Age..........................................................................................................................52 2.10 CONCLUSIONS ON TERTIARY INTERVENTION .................................................................53 3 UK INTERVENTION STUDIES........................................................................................55 3.1 STAGES OF INTERVENTION IN ENGLAND ........................................................................55 3.2 RATIONALE FOR THE SELECTION OF STUDIES.................................................................55 3.3 REVIEW OF STUDIES........................................................................................................56 3.3.1 AcceleRead AcceleWrite.........................................................................................56 3.3.2 Interactive Assessment and Teaching (IA&T)........................................................57 3.3.3 Lexia .......................................................................................................................58 3.3.4 London Borough of Sutton study ............................................................................59 3.3.5 Phono-Graphix.......................................................................................................59 3.3.6 Phonology with Reading.........................................................................................60 3.3.7 Read Write Inc........................................................................................................61 3.3.8 Reading Intervention ..............................................................................................61 3.3.9 SIDNEY ..................................................................................................................63 3.3.10 THRASS..................................................................................................................63