| The prevalence of dyslexia in children at family risk |
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| Hypothesis 1a |
Dyslexia is more common in at-risk than control families. |
| Hypothesis 1b |
Dyslexia is more prevalent in English than in other European (regular) languages. |
| Hypothesis 1c |
The prevalence rates for dyslexia depend upon the cut-off used for “diagnosis.” |
| The home and literacy environment of children at family risk of dyslexia |
|
| Hypothesis 2a |
The home literacy environment will differ between families in which there is a history of reading difficulty from that in families where both parents are free of problems. |
| Hypothesis 2b |
Parents with dyslexia will read less for pleasure than controls. |
| Hypothesis 2c |
Parental literacy skills will account for independent variance in children’s reading outcomes. |
| Endophenotypes of dyslexia |
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| Hypothesis 3a |
Cognitive and perceptual risk factors that are putative endophenotypes should be present in the preschool years before dyslexia is diagnosed. |
| Hypothesis 3b |
Children at family risk of dyslexia will show delayed speech/language development. |
| Hypothesis 3c |
The development of three critical foundations for decoding, viz phonological awareness, symbol knowledge (letters in alphabetic languages) and rapid naming (RAN) will be delayed in children at family risk of dyslexia in preschool. |
| Hypothesis 3d |
Deficits in phonological awareness, symbol knowledge and RAN will characterize dyslexia in the school years. |
| Hypothesis 3e |
Unaffected children at family risk of dyslexia will have poorer literacy skills than controls. |
| Hypothesis 3f |
Endophenotypes of dyslexia will be observed in unaffected children but to a milder degree than in affected children. |
| The predictive relationships between early cognitive and later reading skills |
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| Hypothesis 4a |
Oral language skills will predict literacy outcomes in children at family risk of dyslexia. |
| Hypothesis 4b |
Three critical foundations for decoding, viz phonological awareness, symbol knowledge (letters in alphabetic languages) and rapid naming (RAN) will be predictors of decoding in children at family risk of dyslexia. |
| Interventions for dyslexia |
|
| Hypothesis 5a |
Training in letter knowledge and phoneme awareness will ameliorate decoding difficulties. |
| Hypothesis 5b |
Training in vocabulary and broader language skills will improve reading comprehension. |
