Working memory influences processing speed and reading fluency in ADHD

Abstract

Processing speed deficits affect reading efficiency, even among individuals who recognize and decode words accurately. Children with ADHD who decode words accurately can still have inefficient reading fluency, leading to a bottleneck in other cognitive processes. This “slowing” in ADHD is associated with deficits in fundamental components of executive function underlying processing speed, including response selection. The purpose of the present study was to deconstruct processing speed in order to determine which components of executive control best explain the “processing” speed deficits related to reading fluency in ADHD. Participants (41 ADHD, 21 controls), ages 9-14, screened for language disorders, word reading deficits, and psychiatric disorders, were administered measures of copying speed, processing speed, reading fluency, working memory, reaction time, inhibition, and auditory attention span. Compared to controls, children with ADHD showed reduced oral and silent reading fluency, and reduced processing speed—driven primarily by deficits on WISC-IV Coding. In contrast, groups did not differ on copying speed. After controlling for copying speed, sex, severity of ADHD-related symptomatology, and GAI, slowed “processing” speed (i.e., Coding) was significantly associated with verbal span and measures of working memory, but not with measures of response control/inhibition, lexical retrieval speed, reaction time, or intra-subject variability. Further, “processing” speed (i.e., Coding, residualized for copying speed) and working memory were significant predictors of oral reading fluency. Abnormalities in working memory and response selection (which are frontally-mediated and enter into the output side of processing speed) may play an important role in deficits in reading fluency in ADHD, potentially more than posteriorally-mediated problems with orienting of attention or perceiving the stimulus.

An Exploratory Study on the Relationship between Creativity and Processing Speed for Gifted Children

“…Putting aside the impact of factors contributing to gender differences in processing speed, our findings suggest that gender differences in basic abilities, such as processing speed, might lead to gender differences in other basic or higher order skills, too. For example, considering detrimental effects of processing speed on reading fluency and comprehension (Jacobson et al, 2011), it is reasonable to expect gender differences in reading ability performances. We recommend future researchers to consider such complicated interrelationships among skills when investigating differences in boys' and girls' performances.…”

Does Training in Syllable Recognition Improve Reading Speed? A Computer-Based Trial With Poor Readers From Second and Third Grade

“…In addition to the explanations presented above, the increased comorbidity of learning difficulties may also be linked to other factors such as processing speed ; for review, see Boada et al, 2012) or short-term memory (Jacobson et al, 2011;) that were not controlled for in the study by or in this research. These additional predictors clearly need to be included in further studies exploring reading skills in samples with comorbid learning disabilities or behavioral problems.…”

“…Given the high comorbidity of RD, math disability, and attention deficit in the clinical samples investigated in this research, other candidates besides RAN (or phonological awareness, Study II) should be explored. The literature shows that the most likely candidates to explain the comorbidity of RD, math disability, and attention deficit include processing speed Compton et al, 2012; and short-term memory (Jacobson et al, 2011;.…”

“…Of these two learning phases, RAN is thought to be more strongly associated with arithmetic fact retrieval (e.g., ) than with more complicated calculation tasks . The task used for the assessment of math skills in this research consists of a mixture of single-and multi-digit calculations covering all the basic arithmetical operations; this choice of task may in part explain why the connection between RAN and math was modest in the present research.In addition to the explanations presented above, the increased comorbidity of learning difficulties may also be linked to other factors such as processing speed ; for review, see Boada et al, 2012) or short-term memory (Jacobson et al, 2011;) that were not controlled for in the study by or in this research. These additional predictors clearly need to be included in further studies exploring reading skills in samples with comorbid learning disabilities or behavioral problems.…”

Intervención sobre el funcionamiento ejecutivo en un caso de TDAH: implicaciones en conciencia fonológica y lectura

“…El aumento en el tiempo de respuesta parece relacionarse con la inatención y se asocia además con deficiencias en lectura de palabras, fluidez y comprensión (Jacobson et al, 2011). Katz, Brown, Roth y Beers (2011) encontraron que las personas con TDAH y dificultades de lectura tenían más dificultades en velocidad de procesamiento y memoria de trabajo que niños con TDAH sin dificultades en lectura.…”