Reading Disorders
Dyslexia - Impaired basic literacy skills (inaccurate single word reading, poor fluency and spelling)
Poor comprehenders - normal single word readers but impaired reading comprehension (broader language processing problems)
Dyslexia
Found across languages including logographic languages (e.g., Chinese)
More severe in alphabetic languages that have inconsistent mapping of letters to sounds (English) than those that have consistent mapping (Spanish, Italian)
Predictors: phoneme awareness, rapid serial naming, vocabulary, verbal short term memory
Diagnosis Discrepancy Model
Ability vs. Achievement
Tests
Battery of tests are necessary so that comparisons can be made between tests that generally are not as affected by dyslexia to those that are tapping common weaknesses in dyslexia (reading accuracy, fluency, spelling) and associated cognitive difficulties (phonological awareness, rapid naming, nonverbal precessing speed, verbal short term memory, vocabulary)
However, there is no characteristic deficit or profile that can be used to rule in or rule out diagnosis. Be alert to the patterns that are inherent to dyslexia
Achievement Tests
Woodcock-Johnson IV
Tests of:
Cognitive Abilities
Achievement
Oral Language
Woodcock-Johnson IV Test of Cognitive Ability
Measure of aptitude or IQ
Woodcock-Johnson IV Achievement vs. Oral Language Tests
Achievement focuses on written skills
Oral Language focuses on oral skills
Woodcock-Johnson IV Oral Language Tests
Assesses important oral language abilities
Woodcock-Johnson IV Achievement Test
Italicized
11 Standard Battery Subtests
9 Extended Battery Subtests
Terminology
AE/GE
SS - Standard score (mean=100, SD=15)
Rest are Italicized
Focal Reading Tests
Gray Oral Reading Test (GORT-5)
Nelson Denny Reading Test
Comprehensive Test of Phonological Processing (CTOPP-2)
Florida Nonsense Passages
Diagnosis PSW
Dependent on convergent data from HOT
Key Sx: difficulties learning to read & spell generally apparent from beginning of formal literacy instructions
Virtually all with dyslexia have difficulty:
- Reading aloud
- Learning phonics
History
Three aspects of history particularly informative:
1. Family history
2. School history
3. Reading and language history
Observations
Often report not liking reading or embarrassed or reluctant to read aloud
Pay attention to what is most difficult:
- More difficulty on timed tests than untimed test of word, nonword, and paragraph level reading (sensitive to dyslexia)
**Analysis of specific reading and spelling errors
Error Analysis
Slow and halting in oral reading (especially with younger readers; old readers may have over learned vocabulary)
Misread “a,” “the,” and prepositions because working hard to decode and relying on context so miss the little words (can be puzzling to parents)
Whole-world guesses based on visual similarity to target words (e.g., tired for tried). Using visual similarity rather than phonological coding
Reading a nonword as a visual similar real word (e.g., clip for clup)
Because weak phonetics skills, they use similarity in word recognition
Dysphonetic errors, especially consonants added, omitted or substituted (e.g., exetive for executive)
But the occurrence in dyslexia is low and those without dyslexia make reversal errors
Also, so not diagnostic
But in age 9 and over reversals have diagnostic significance
Most commonly b and d confusion
Heterotypic Continuity
Early years manifests as differences in speech perception and babbling
Then vocabulary and syntax
Later phonemic awareness
Beginnings of Dyslexia occur very early, perhaps prenatally
But early signs do not have enough sensitivity and specificity to diagnose individuals prior to formal literacy instruction
Tasks emphasizing speed become increasingly important diagnostically as literacy development progresses
Etiology
Dyslexia is the intersection of an evolved behavior (language) and a cultural invention (literacy)
Both genetic and environmental factors contribute to dyslexia