1. Differences in SPECT Perfusion in Children and Adolescents with ADHD
Yassin S. M.S, Spengler K. M.S, Amen D. Ph.D., Willeumier K. Ph.D, Taylor D. Ph.D, & Golden C., Ph.D.
Discussion
Attention deficit hyperactivity disorder (ADHD) is believed to encompass a deficit in behavioral inhibition. Four executive neuropsychological functions are believed to depend on behavioral inhibition for their effective execution. These include working memory, self-regulation (for affect, motivation, arousal), internalization of speech, and behavioral analysis and synthesis. It is also theorized that ADHD is related to secondary impairments in these executive abilities and the motor control they afford.
The results of this study suggest that multiple brain regions are associated in ADHD, particularly the areas of the frontal and temporal lobes. This indicate that the functional abilities of the frontal and temporal lobes are implicated in children and adolescents with ADHD and this may account for their difficulties in motor control, problem solving, and self-regulation difficulties. Also, in addition to frontal and temporal lobe areas, other brain regions may be contributing to ADHD symptoms. Thus, this study shows that children’s and adolescents’ deficits in ADHD may reflect a generalized cognitive impairment rather than cognitive impairment in just the frontal lobe.
References
Roth, R.M., & Saykin, A.J. (2004). Executive dysfunction in attention deficit/ hyperactivity disorder: cognitive and neuroimaging findings. The Psychiatric clinics of North America, 27(1),
Durston, S. (2003). A review of the biological bases of ADHD: What have we learned from imaging studies? Mental Retardation and Developmental Disabilities Research Reviews, 9,
For more information please contact Sarah Yassin at
Research Question
ADHD is characterized by a persistent maladaptive pattern of inattention and/or hyperactivity-impulsivity that is inconsistent with the individual’s developmental level. The prevalence of ADHD is between 3-7% in children (Durston, 2003).
Over the last decades, numerous research has been done on this disorder and great progress has been made, but the precise etiology still remains unclear. Children with ADHD show poor inhibitory or cognitive control. It has been proposed that deficits in executive functioning associated with ADHD may be due to the core deficit of inhibitory control that is implicated in working memory, goal-directed behavior, and emotional-self control (Durston, 2003).
Research studies have identified precise cortical and subcortical structural differences in the brain of individuals with ADHD and those without ADHD using various physiological measures of brain activity. Low frontal lobe activity were found in several studies comparing children with and without ADHD, and low temporal lobe activity were inconsistently found between children with ADHD and children without ADHD during concentration tasks (Roth & Saykin, 2004).
This study aimed to look at the differences in brain function at baseline between children and adolescents diagnosed with ADHD and those without ADHD by using results obtained from single-photon emission computerized tomography (SPECT) scans .
Methods
Participants were 2168 children and adolescents with ADHD (M age=12) and 906 children and adolescents without ADHD (M age=12). In the ADHD group, 604 were females and 1557 were males, and 1105 were identified as Caucasian (36%). In the non-ADHD group, 309 were females and 593 were males, and 353 (11%) were Caucasians. Differences in their brain regions were analyzed using SPECT scans at baseline.
Results
A MANOVA was used to assess the differences between brain activities of children and adolescents with and without ADHD. Significant differences were found for several brain regions between the two groups. Multiple areas of the cerebellum, frontal lobe, occipital lobe, parietal lobe, post central gyrus, and temporal lobe were significantly different (p<.001) between the two groups. Frontal and temporal lobes were found to have the highest number of areas that were significantly different between the two groups.