Neuropsychological Profiles and Predictors of Reading Performance of Children with Developmental Delay with and without Cognitive Difficulties

摘要

Abstract A revised Developmental Delay (DD) category became effective in Arizona on September 30, 2009 and allows children who demonstrate significant delays in at least two developmental areas to receive services in special education up to age 10. In order for the educational team to determine that a student meets the criteria for DD, an assessment in all five developmental areas, including cognitive, physical, communication, adaptive, and social/emotional must be completed. However, areas typically included in a neuropsychological assessment, like attention and executive functioning or memory and learning, are typically not part of an educational evaluation and have the potential to adversely affect learning when there are deficits in these areas. DD is a highly prevalent group that has a wide variety of genetic, environmental, and societal risk factors. The definition varies greatly in research, education, medical or health-related fields, as well as by culture. Since the DD category is viable until age 10, outcome studies have been conducted to find out if children with DD continue in special education and if so, under what categories. It has been found that children with DD generally stay in special education and continue receiving services, most often as students with specific learning disability, mild intellectual disability, and speech/language impairment, in addition to other categories. There is limited information in the available literature regarding the neuropsychological strengths and weaknesses for this prevalent group. Moreover, there is limited information available regarding the possible predictors of reading achievement for children with DD. The first aim of the study was to determine how much variability in performance there was for children who met the educational criteria for DD in Arizona as well as to assess strengths and weaknesses compared to normative means. The second aim of this study was to find out if two specific scores from a neuropsychological battery found to be significantly lower in children with a reading disorder were also significant predictors of reading performance in children with DD. A third aim involved an exploratory analysis to determine if there was evidence of a pattern of strengths and weaknesses by delay type. Thirty-three children with DD ages 5 to 9 years were recruited for this study from a single school district in Southern Arizona. Children were administered measures of cognition, attention and executive functioning, memory and learning, sensorimotor skills, and visuospatial processing, and reading. The parent/guardian of the child completed a structured developmental history. For the first aim, the total sample was split into two groups by presence of cognitive delay and analyzed separately. Qualitatively, the data in the form of box-plots was examined. Levene's and Nonparametric Levene's tests were used to quantitatively evaluate variance in score distributions. Single sample t-tests were used to compare group mean scale or subscale scores to the appropriate normative means. The second aim was analyzed using the total sample of children with DD. Stepwise linear regression models were used to determine if Speeded Naming and Inhibition Naming Total Completion Time scores significantly predicted reading performance as measured by the Reading Cluster score from the WJ IV ACH for all children with DD. Two other subtest scores, which were observed to be within normal limits in children with reading disorder on the NEPSY-II special group study, were also analyzed with stepwise linear regression to confirm that they did not predict reading in children with DD, namely Memory for Designs Total Score and Geometric Puzzles. Lastly, for the third aim, those with each delay type were analyzed separately from those without the delay type (e.g., no communication delay and communication delay). Like the first aim, box-plots were generated to visually represent the data. DD group mean scores of each scale or subscale were also compared to the appropriate normative means by single sample t-tests. Results from this study indicated that the variation in the scores was not significantly different between groups, except for a measure of graphomotor speed and precision. Children with DD with a cognitive delay were found to exhibit a wide range of deficits, including deficits in cognition, reading, attention and executive functioning, language, memory and learning, sensorimotor, and visuospatial processing. Children without cognitive impairment did not demonstrate impairments in cognition and reading and demonstrated specific skill deficits for sustained attention, speeded naming with accuracy, immediate and long-term visual memory, memory for organized verbal information, phonological short-term memory, and fine motor speed. When the total sample was analyzed together, three high reading scores were identified as outliers from group reading performance. Both predictor variables were found to be moderately related to reading whether the outliers were in or out. Only one of the two predictors were found to significantly contribute to the predictive model whether the outliers were in or out yet the strength of the prediction was weak, suggesting there are likely better predictors of reading for children with DD. In the analysis of the non-predictors, when the outlier scores were left in, Geometric Puzzles, a measure of visuospatial perception and mental rotation was indicated as a significant predictor of reading. When the outliers were removed, neither score was significantly related with reading. Lastly, meaningful group strengths and weaknesses were seen when the total sample of children with DD was broken into groups by delay, even when the majority performed below normative means. The results of this study indicate that children with DD are at increased risk for significant difficulties in many of the areas included in neuropsychological assessment. This points to the need for many of these areas, namely attention and executive functioning, memory and learning, and visuospatial processing to be included in a comprehensive evaluation in the school setting. Moreover, knowledge of group strengths and weaknesses can aid intervention selection and implementation in addition to appropriate accommodations to facilitate learning. This can inform intervention implementation and design. More research is needed in this area to have a better understanding of how neurocognitive skills relate to reading since the predictors selected for this study were not strong predictors of reading performance for children with DD. Visuospatial perception and mental rotation may be more highly related for children with DD that have higher reading skills.