Abstract

1
Reading and Spelling of Children with Speech
Sound Disorders Genetic Influences
Barbara A. Lewis1, Iris Kuo2, Lisa A.
Freebairn1, Amy J. Hansen1, Sudha Iyengar2,
Catherine M. Stein2 1Department of Communication
Sciences, 2Department of Epidemiology and
Biostatistics Case Western Reserve University,
Cleveland, Ohio Supported by National
Institutes of Health, National Institute on
Deafness and Other Communication Disorders, Grant
DC00528 NIDCD
Inclusion criteria
Results of Linkage Analyses
Abstract
Summary and Conclusions

• Families for the study were recruited from the
  caseloads
• of speech/language pathologists in Northeast
  Ohio.
• Proband children were required to have
• Normal hearing, nonverbal IQ, and oral motor
  skills.
• Deficits of speech sounds in single words as
  evidenced by a score below the 10th percentile on
  the Goldman-Fristoe Test of Articulation (GFTA),
  a minimum occurrence of four phonological process
  errors and a severity rating of 3-4 (moderate to
  severe) on the Khan-Lewis Phonological Analysis
  (KLPA)
• Speech-sound errors in conversational speech with
  a rating of less than 90 percent consonant
  correct (PCC).

Children with speech sound disorders (SSD) and
their siblings were assessed at preschool (ages
4-6 years) and followed at school-age (7-12
years). Measures of reading decoding and
comprehension, spelling and written language were
administered at follow-up. Results showed that
the proband children performed significantly
poorer than their unaffected siblings on all
follow-up measures. Genetic linkage studies
demonstrated linkage for reading, spelling, and
written language measures to regions on
chromosomes 1,3, 6, and 15 that were previously
associated with oral motor skills, articulation,
phonological memory, and vocabulary at the
preschool testing. Findings suggest genetic
influences on an underlying phonological
processing deficit that may account for the
co-morbidity of early childhood SSD and later
reading, spelling, and written language
difficulties.

• Children with early childhood SSD and their
  siblings were followed at school age and examined
  on measures of reading, spelling, and written
  language. Results showed that proband children
  differed from their unaffected siblings on all
  measures. Genetic linkage analyses showed
  linkage for these measures to regions on
  chromosomes 1,3, 6, and 15. These regions had
  previously demonstrated linkage to early
  childhood measures of oral motor skills,
  articulation, phonological memory, and
  vocabulary. Findings support the shared genetic
  basis for SSD, reading, spelling, and written
  language. Regions on chromosomes 1,3, 6, and 15
  may harbor genes that influence spoken and
  written language skills including reading
  decoding, reading comprehension, spelling,
  vocabulary, language comprehension, and written
  syntax. Findings for individual chromosomes are
  as follows
• Chromosome 1 showed linkage to reading
  decoding, spelling and writing skills. Our
  previous findings at the earlier assessment,
  showed linkage to vocabulary, language,
  articulation, and phonological memory at this
  region.
• Chromosome 3 showed linkage to reading
  decoding, single word reading, spelling,
  vocabulary, and written syntax. Our previous
  findings at the earlier assessment showed
  linkage of repetition of multisyllabic real and
  nonwords and vocabulary.
• Chromosome 6 showed linkage to spelling of
  predictable words. This replicates previous
  studies that have reported linkage of reading
  and spelling to this region.
• Chromosome 15 showed linkage to reading
  decoding, single word reading, spelling and
  language comprehension. Our previous findings
  showed linkage of oral motor function,
  articulation, and phonological memory.

Follow-up Measures
Introduction

• Woodcock Reading Mastery Test (WRMT)
• Word Identification Word Attack
• Wechsler Individual Achievement Test (WIAT)
• Reading Comprehension Listening Comp.
• Test of Written Spelling (TWS)
• Total Predictable, and Unpredictable scores
• Test of Written Language (TOWL).
• Thematic Maturity Contextual Vocabulary
• Contextual Style Syntactic Maturity

Studies that have followed children with early
childhood SSD have found later academic
difficulties in 50-75 of their participants.
Linguistic deficits in reading and spelling may
persist into adolescence and adulthood for some
individuals. The high rate of co-morbidity of
SSD and later reading and spelling difficulties
suggests a common underlying phonological
representation deficit. The purpose of this study
is two-fold First we examine school-age outcomes
of children with early childhood SSD on measures
of reading, spelling, and written language.
Second, we examine genetic influence on these
outcomes through a linkage study that examines
regions of chromosomes associated with dyslexia
and linked to speech and language disorders in
our previous studies.
Group Comparisons on Measures
Results from Haseman-Elston linkage results for
chromosome 6 and 15.  The P-value of each trait
at specific chromosomal locations. 
Participating Families