Comparing the efficacy of phonological awareness intervention with neuropsychological intervention in children with specific reading disorder
Degree GrantorUniversity of Canterbury
Degree NameDoctor of Philosophy
Phonological awareness is known to be associated with reading disorder. Intervention for specific reading disorder that focuses on training to improve phonological processing abilities has been found an effective means of addressing reading difficulties experienced by children. However, little is known as to what happens to other neurocognitive abilities associated with the process of reading but that are not causally linked to it. Some of these cognitions include attention, executive functions and verbal and visual memory. A series of three studies explored the relation between neuropsychological skills and phonological abilities in children with specific reading disorder. The first step in the studies involved establishing deficits in associated cognitive abilities in children with specific reading disorder. Children attending the Literacy Clinic, Department of Communication Disorders, University of Canterbury, Christchurch, New Zealand, are screened for the presence of specific reading disorder. They are routinely assessed on reading and phonological processing measures before an intervention programme is initiated. Four such children who were assessed and identified as having specific reading disorder without speech language difficulties were chosen for the study. These children, who ranged in age from 7 to 15 years, referred to as the RD group, were assessed during the week before the onset of the intervention for the neuropsychological functions of attention, executive functions, verbal and visual learning, and memory. After the assessment (termed pre-intervention assessment), they were provided with phonological processing intervention. The intervention programme was carried out by trained speech-language therapists and lasted for 10 weeks. Two sessions a week were conducted, giving a total of 20 sessions. The week after completion of the intervention, the children were assessed once again on the same neuropsychological, reading and phonological awareness tests used before the intervention (termed post-intervention assessment). The results of the pre-intervention assessment were compared with the assessment of a group of typically developing group of children without reading disorder (N = 4; age range 8 to 10 years; referred to as the NRD group). Results indicated that, at pre-intervention assessment, the specific reading disorder (RD) group had deficits in verbal fluency and inhibitory control whereas the typically developing (NRD) group did not. The RD group also differed significantly from the NRD group in reading accuracy and comprehension. After the intervention, the RD group was assessed on reading, phonological processing, and neuropsychological tests. The group showed an improvement in reading accuracy and phonological processing. Of all the neuropsychological functions, only set shifting and visuo-spatial working memory scores showed a significant change in response to intervention. Deficits in executive functions and reading comprehension difficulties persisted. It was hypothesised that the RD group improved in reading accuracy in response to the phonological awareness intervention. However, the persistent reading comprehension difficulties were hypothesised as attributable to the presence of the executive function deficits noticed in the RD group. The exploratory study helped identify the presence of neuropsychological deficits in children with specific reading disorder in addition to their reading and phonological deficits. The study also established that phonological awareness intervention brought about a change in some neuropsychological function while other deficits persisted. The phonological awareness intervention used in the first study was developed for children in New Zealand. The second study hypothesised that, if effective, this intervention would help address reading deficits found in other populations. Children from a culture outside New Zealand accordingly the same intervention as the New Zealand children received in the first study. Children in Bangalore, India, 10 to 12 year of age and under-performing in their class, were screened for the presence of specific reading disorder. From this screening, 20 children with specific reading disorder (the RD group), with average to above average intelligence and without co-morbid psychiatric conditions were chosen to participate. Twenty children were randomly allotted to one of two treatment conditions. The first group of 10 children (the PA group) received phonological awareness intervention. The second group of 10 children (the NP group) received neuropsychological intervention. All 20 children were assessed on reading, phonological awareness tests and neuropsychological tests before and after intervention. Phonological measures included, Queensland University Inventory of Literacy (QUIL, ) Sthal and Murray, Phonological awareness probes of tracking speech sounds and non-word reading tests. Neuropsychological measures included Controlled Word Association test (COWA), Digit Span, Spatial Span, Stroop Colour-Word Test Coulor trails (A & B), Ray Auditory verbal learning test, Rey Osterriech Complex figure test and block design. The scores from the pre-intervention assessment were compared to the assessment data for 20 typically developing, non-reading-disabled children (referred to as the control group). The control group was assessed once on neuropsychological tests and reading and phonological awareness measures (QUIL only). The results indicated that the 20 children with reading disorder (the RD group) differed significantly from the control group on reading abilities. In addition, the two groups differed significantly on neuropsychological measures of attention (Colour Trail, Form A), set-shifting (Colour Trail, Form B), word reading and interference control (Stroop Colour-Word Test) and phonological awareness measures of non-word reading, syllable identification, visual rhyme, spoonerism, phoneme detection and phoneme deletion. After intervention, the RD group was again assessed on reading, phonological awareness and neuropsychological measures. Both the intervention groups (PA and NP) showed improvements on reading. Both groups also made significant gains on neuropsychological measures and phonological awareness measures. The PA group showed significant changes in verbal fluency, visual scanning and attention (Colour Trails, Form A), word reading (Stroop Colour-Word Test, verbal memory (Auditory Verbal Learning Test), immediate visual memory (Complex Figure Test) and visuo-construction abilities (Block Design Test). Phonological measures that showed significant increase in response to intervention in this group included non-word reading, phoneme detection, phoneme segmentation, phoneme deletion and tracking of syllable sound changes via use of coloured blocks and letter tiles. The NP group showed significant change in neuropsychological functions such as verbal fluency, word reading and interference control (Stroop Colour-Word Test), verbal learning (Auditory Verbal Learning Test), immediate visual memory (Complex Figure Test) and visuo-construction ability (Block Design Test). The NP group also improved significantly on phonological awareness measures such as syllable identification, spoken and visual rhyme, spoonerism, phoneme detection, phoneme deletion and tracking of syllable sound changes via use of coloured blocks. This second study established that the two interventions helped improve reading abilities equally. However, the interventions differentially affected neuropsychological and phonological awareness functioning in the participants. The third study explored the changes seen in the second study’s two treatment groups (Group PA and Group NP) three months after the conclusion of the intervention programme. During the three-month period between the post-intervention assessment and the follow-up assessment, all 20 children attended regular school. They received no special help or input for their reading and spelling difficulties during this period. The follow-up assessment consisted of the same tests of reading and neuropsychological measures used at the pre- and post-intervention assessments. The results showed that the groups had maintained the gains evident at the time of the post-intervention assessment on reading measures. The PA group’s performance on the neuropsychological measures and phonological measures showed significant changes in digit span and interference control. In addition, a significant increase from the pre-intervention measures, not observed at the post-treatment assessment, was observed for set-shifting, verbal learning and memory and now-word reading. Visuo-spatial working memory showed a trend towards significance for the NP group on the follow-up assessment. Most other neuropsychological functions did not differ significantly from those evident at the time of the post-intervention assessment. The NP group, like the PA group, showed a significant increase between pre-assessment and follow-up assessment on non-word reading, visual scanning, verbal learning and visual perception. The increase noticed in these measures at the time of the post-treatment assessment, however, was not significant. Comparisons between the PA and NP group at follow-up revealed that the PA group’s performance was significantly better than the NP group’s on digit backward and interference control, while the NP group performance was significantly better than the PA group’s on verbal fluency. The two groups were comparable on all other neuropsychological, phonological awareness and reading measures. The improvements noticed in both groups immediately after the intervention and then three months after intervention were hypothesised to have occurred because the interventions addressed reading along with other cognitive abilities (e.g., executive functions, attention, verbal learning and memory, visual learning and memory) addressed in the study. The improvements noticed in both groups after three months after intervention was hypothesised to be the outcome of improvements in the neuropsychological functions. The series of three studies conducted as part of this research work has helped identify neuropsychological deficits in children with reading disorder that persisted after phonological awareness intervention. The provision of two different interventions to children with reading difficulties showed that these had positive outcomes not only for reading and phonological awareness but also for neuropsychological functioning. The most important conclusion drawn from the findings of the three studies that form this doctoral research is that intervention for reading disorder is most likely to be effective when it addresses the reading and other associated cognitive skills that underlie the reading process. The two interventions used in the study had a similar effect on reading. Both helped the participating children improve their reading scores and both helped maintain those improvements over time. It is hypothesised that the improvement observed was probably sustained over time because both interventions could have addressed the associated deficits (in addition to reading difficulties) known to occur in children with reading disorder. The efficacy of the phonological awareness intervention documented in the studies is strengthened by the finding that it was effective in treating reading disorders in children from different cultural and educational settings (New Zealand and India).