Slow Processing Speed and Learning Disabilities

Some kids are naturally fast. They run, talk, complete homework assignments, and do all sorts of things at a rate that seems appropriate for their age. Other kids don’t, or perhaps it would be fairer to say they can’t. These are kids who may have what are known as processing speed deficits.

What is processing speed?

Processing speed involves one or more of the following functions: the amount of time it takes to perceive information, process information, and formulate or enact a response. Another way to define processing speed is to say that it’s the time required to perform an intellectual task or the amount of work that can be completed within a certain period. Even simpler, one can define processing speed as to how long it takes to get stuff done.

There are three main components of processing speed (Burgess, 2016):

  • visual processing: how quickly a student’s eyes perceive information and relay it to the brain (such as reading directions or noticing a teacher’s hand gestures)
  • auditory processing: how quickly a student hears a stimulus and reacts to it (such as following oral instructions or participating in a discussion)
  • motor speed: how strong a student’s fine-motor agility is, leading to academic fluency (such as filling out timed math worksheets)

Deficits in cognitive skills are said to affect the learning process significantly. Educators and parents should acknowledge this, be on the lookout for abnormal cognitive development, and ensure the successful development of these skills. Processing speed is one of the main components of cognition and is crucial in learning, academic performance, intellectual development, reasoning, and experience.

Slow processing speed and learning disabilities

Slow processing speed is not a formal learning disability, but it can play a part in learning and attention issues like dyslexia, ADHD, dysgraphia, dyscalculia, and auditory processing disorder.

When a student is slow at processing, certain academic tasks can take them longer to do than the average student. According to the authors of Bright Kids Who Can’t Keep Up, “processing speed does interact with other areas of cognitive functioning by negatively impacting the ability to quickly come up with an answer, retrieve information from long-term memory, and remember what you’re supposed to be doing at a given time” (Braaten and Willoughby, 2014, p.4).

Evidence suggests that processing speed problems are a major underlying factor in reading disability and ADHD, as the two disorders often go hand in hand (Shanahan et al., 2006). Studies also suggest the slow reading and slow motor responses, often seen in those with dyslexia, may be related to slow processing speed (Stoodley and Stein, 2006).

Slow processing speed and depression

Adolescents with slower processing speed may be at increased later risk of anxiety and depression, according to research done at Edinburgh University. The results add new evidence that lower cognitive ability may be a contributor to depression, rather than a consequence of it.

The researchers analyzed data from 705 Scottish participants in a study including follow-up from adolescence into adulthood. At age 16, the participants were evaluated on a simple test of cognitive processing speed: reaction time in pressing keys corresponding to numbers (1 to 4) flashed on a screen.

At age 36, the participants completed standard questionnaires assessing depression and anxiety symptoms. The relationship between reaction time in adolescence and mental health in adulthood was assessed, with adjustment for a wide range of other factors (education, lifestyle habits, etc).

Slower cognitive processing speed — that is, longer reaction time — at age 16 was associated with increased anxiety and depression symptoms at age 36.

Previous studies have shown that people with more severe depression have slower reaction times and other cognitive deficits. It has generally been assumed that this “psychomotor slowing” is a consequence of depression, rather than a risk factor for it. The Edinburgh study suggests that slower processing speed may contribute to the development of mental health disorders — possibly by leading to “increased stress and difficulties responding to adversity earlier in life.”

Improving processing speed

A collaborative study between Edublox, the University of Pretoria (UP), and a primary school in Pretoria CBD has paved the way to show how Edublox Online Tutor can contribute to processing speed development. The study was analyzed as a post hoc research project by Naseehat Dawood as part of her master’s degree in research psychology under the guidance of Professor David Maree, former Head of the Department of Psychology at UP.

Sixty-four 2nd grade students were divided randomly into three groups: group 1 completed 28 hours of Edublox’s Development Tutor over a 3-week period; group 2 was exposed to computer games, while group 3 continued with their schoolwork.

Findings suggest that exposure to the Edublox program significantly improved the post-test scores in the processing speed domain. Descriptive statistics showed that while scores improved for all three groups, the children exposed to the Edublox program improved by a much greater percentage than the other groups. A repeated-measures ANOVA test confirmed the descriptive results and showed significant differences in the improvements in mean processing speed of the children in groups 1, 2, and 3.

Mean processing speed scores before and after
Mean plots of children’s processing speed tests

This study follows a trial by educational specialist Dr. Lee DeLorge in Ohio, who put the Edublox program to the test. Sixty-seven students aged 5 to 18 with ADHD, dyslexia, dyscalculia, and non-specific learning disabilities participated in her study. Ninety-four percent of the students improved significantly in processing speed. Results were as follows:

  • Thirty-five students with ADHD showed a combined increase of 52.45 percent, from a pre-test average of 37.24 percent to a post-test average of 89.69 percent.
  • Thirteen dyslexic students showed a combined increase of 46.76 percent, from a pre-test average of 41.31 percent to a post-test average of 88.07 percent.
  • Two students were diagnosed with dyscalculia and showed a combined increase of 57.38 percent, from a pre-test average of 39.76 percent to a post-test average of 97.14 percent.
  • The remaining learners were non-specific learning-disabled and showed a combined increase of 64.14 percent, from a pre-test average of 30.40 percent to a post-test average of 94.54 percent.


In an interview broadcast on WKYC, a television station located in Cleveland, Ohio, Dr. DeLorge explained cognitive skills and how Edublox methodology strengthens a child’s cognitive skills.




Braaten,  E., & Willoughby, B. (2014). Bright Kids Who Can’t Keep Up. Help Your Child Overcome Slow Processing Speed and Succeed in a Fast-Paced World. Guilford Press: New York.

Burgess, K. (2016). Understanding and addressing processing speed deficits in the classroom. LDOnline.org

Lee, Cynthia Wei-Sheng PhD; Liao, Chun-Hui MD; Lin, Cheng-Li MSc; Liang, Ji-An MD; Sung, Fung-Chang PhD; & Kao, Chia-Hung MD (2015). Depression and risk of venous thromboembolism: A population-based retrospective cohort study. Psychosomatic Medicine.

Shanahan, M. A., Pennington, B. F., Yerys, B. E., Scott, A., Boada, R., Willcutt, E. G., Olson, R. K., & DeFries, J. C. (2006). Processing speed deficits in attention deficit/hyperactivity disorder and reading disability. Journal of Abnormal Child Psychology, 34, 584-601.

Stoodley, C. J., & Stein, J. F. (2006). A processing speed deficit in dyslexic adults? Evidence from a peg-moving task. Neuroscience Letters, 399, 264-267.