Four Types of ADHD
I was very interested when reading the research paper from Goth-Owens, T. L., Martinez-Torteya, C., Martel, M. M., & Nigg, J. T. (2010) about the different types of ADHD. The researchers wanted to provide supporting evidence that a subgroup to ADHD-PI (predominately inattentive) exists. Especially interesting was the four types of cognitive weaknesses measured to discern supporting evidence of the subgroup. We already know that we have Attention Deficit Hyperactivy Disorder as the main umbrella where subgroups of Predominately Inattentive – ADHD-PI (5 symptoms of hyperactive-implusive), Combined (Inattentive along with hyperactive/impulsive) ADHD-C and Predominately Hyperactive-Impulsive ADHD-PHI.
What was very interesting is that the research uses cognitive weaknesses within four types of processing to provide supporting evidence for a 4th group that met the criteria of ADHD-PI but had two or fewer hyperactive-impulsive symptoms. They called this group ADD and it was resurrected, per se, into use in 2005. The challenge is that the researchers recognized that ADD may not adequately be reflected within DSM IV under ADHD-PI. Even today, there is conflicting agreement on classification and diagnosis of ADHD. Frick and Nigg (2012), also make a distinction that ADHD is neurodevelopmental in nature and not purely behavioral even though there is some overlap in behavioral diagnosis. Their recommendations and findings are that ADHD should present in DSM-V as neurodevelopmental in nature. There is ongoing research and discussion about the classifications of ADHD and how they will be represented in DSM-V due out in 2013.
Cognitive Differences in Types of ADHD
The researchers used processing tests to provide the supporting evidence that there is in fact a fourth group of youngsters with ADHD. This group, ADD, is predominately inattentive with two or fewer hyperactive/impulsive symptoms. The interesting part for me, as a brain trainer, was the examination of cognitive skills and how the weak cognitive processing differences impacted the working memory's ability. We often hear that children with ADHD have low working memory and because of that low ability to process within this memory area, their attention is weak and academics suffer. This paper provides supporting evidence that, in fact, the weak working memory is a result of weak cognitive processing skills (which could be the result of other weak cognitive skills). The main takeaway, for me, was that the weak cognitive processing skills can be strengthened using appropriate interventions based on The Theory of Neuroplasticity (a.k.a. brain training).
Four Different Types of Cognitive Processing Speeds That Can Be Measured
This study had a purpose to show that a subset of youngsters with ADHD-PI existed to be known of ADD (with two or fewer hyperactive/impulsive symptoms). The research was based on an original study that noted ADHD is associated with slower speed of processing overall (Shanahan et al., 2006). Additionally, youngsters with ADHD-PI exhibit slower processing speed than those with ADHD-C ( Calhoun & Mayes, 2005; Chhabildas, Pennington, & Wilcutt, 2001; Nigg, 2001; et. al). The researchers used the processing-speed hypothesis to provide evidence of differences amongst processing speeds between ADD, ADHD-PI and ADHD-C to justify the additional classification of ADD. I was interested in this research to discover which processing speeds were tested and how they categorized the types of processing speeds.
The following four types of processing speeds,interference control, verbal output speed, perceptual/motor speed, and set-shifting speed were assessed and expected to follow the hypothesized trend: So, how did the researchers measure these processing speeds because one type of processing speed assessment may not be assessing all four types of processing? Are you still with me?
In brain training, brain trainers all use the commonly known Stroop Test. However, did you know there were different types of Stroop Tests based on what is being measured? We use our Stroop Tests for a variety of measures as did the researchers in this report. These researchers used Stroop Tests to measure two types of tasks: speed of response and speed under conditions of interference. The most widely known Stroop Test is the Stroop Color/Word Test, which challenges managing interference.
The Stroop (using a version that has an incongruent condition for color/word) the researchers could measure complex cognitive processing speed. Here your child would need to read off the color of the ink the word is printed in as fast as possible while not getting distracted by the word itself.
Using the the Stroop word-naming and color-naming test would measure verbal output speed working semantic processing. Here the child would ignore the color of the ink the word is printed in and just read the printed word out loud.
Additionally, perceptual/motor output speed and set-shifting speed were used in measuring the processing-speed domain of cognitive skills. For the perceptual/motor output speed the researchers used the Trailmaking Test Part A which requires your child to draw a line between numbers in sequential order. This involves visual search and automatic sequencing. For set-shifting speed, the researchers used Trailmaking Test Part B. This test measures how efficiently your child can shift attention across task demands. Your child need to correctly sequence numbers and letters in order by alternating between letters and numbers.
So, what were the results of the research? The study did provide supporting evidence that a non-hyperactive group of ADHD youngsters may exist, validated by slower cognitive processing and interference control. The ADD group differed from the ADHD-C on one out of four hypothesized measures–the Stroop interference. The cognitive problems of this group are more severe than those of the ADHD-C. Also found was the ADHD-PI group performed much slower than controls on perceptual/motor output speed and set-shifting speed. The researchers believe that these cognitive skill deficits may be specific to ADD. The researchers also believe that the findings from the Trail Making A with both inattentive subtypes may have important links to Developmental Coordination and Written Expression Disorders usually found as a comorbidity of youngsters with inattentive types of ADHD.
From a brain trainer and educator's perspective, the study helps to provide a road map of complex cognitive processing skills that should be assessed and focused upon through the brain training program.
Goth-Owens, T. L., Martinez-Torteya, C., Martel, M. M., & Nigg, J. T. (2010). Processing Speed Weakness in Children and Adolescents with Non-Hyperactive but Inattentive ADHD (ADD). Child Neuropsychology, 16(6), 577-591. doi:10.1080/09297049.2010.485126
Current Issues in the Diagnosis of Attention Deficit Hyperactivity Disorder, Oppositional Defiant Disorder, and Conduct Disorder Paul J. Frick1 and Joel T. Nigg2
Annu. Rev. Clin. Psychol. 2012.8:77-107. Downloaded from www.annualreviews.org