Attention-deficit hyperactivity disorder (ADHD) is a common condition characterized by certain behaviors like impulsivity, inattention, procrastination and hyperactivity. ADHD can be diagnosed in adults and children but it is more common in school-aged children. Currently, there is not a lot known about the causes of ADHD. More than likely, a combination of genetic, environmental and developmental factors leads to ADHD.
ADHD brain scans are used to study how ADHD affects the brain. The overall goal of this research is to understand differences in brain structure and activity between individuals diagnosed with ADHD compared to individuals without the condition. Research also suggests that brain development in ADHD may be slightly altered. As technology improves, it is likely that medical researchers will uncover more information about ADHD and how to effectively treat it.
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Differences in Brain Structure and Function
Are there clear differences between the brain of someone who has ADHD compared to the brain of someone who doesn’t have the disorder? There are numerous brain imaging technologies that allow medical professionals to analyze structural and activity differences in the human brain.
A study conducted in 2017 found that several ADHD brain structures were markedly smaller than the brain structures of healthy control individuals. As far as ADHD brain function, the decreased size of brain structures was associated with delays in development. Another study conducted in 2018 in preschoolers found similar results to the 2017 study, where there was a reduction in size in several important brain regions. Such information can help overcome the stigma that children with ADHD are simply “troubled” and that this condition results from bad parenting.
It appears that an individual with ADHD’s brain chemistry is quite different from an individual without the disorder. Besides brain scans that show differences in brain structure, there are also new United States Food and Drug Administration (FDA) approved tests that can help diagnose ADHD by measuring brain waves.
Types of Brain Imaging for ADHD
What are the different types of ADHD brain imaging? Additionally, how can ADHD brain scans demonstrate differences between adults and children who have ADHD versus those who do not? While there have only been a few large-scale ADHD brain scan studies, the information from these studies has been invaluable and will pave the way for future research. Currently, there are a few different brain imaging modalities that may help confirm an ADHD diagnosis.
Neuropsychiatric EEG-Based Assessment Aid or NEBA, is a type of test that measures brain waves. Using a technology referred to as electroencephalogram (EEG), electrical impulses that are produced from nerves found in the brain can be recorded. The NEBA system for ADHD is an easy test to administer and only takes approximately 15 minutes. This test works great for children because it is noninvasive. The brain waves that are recorded can help medical professionals diagnose ADHD. There are different types of brain waves in the human brain including beta and theta waves. Children with ADHD have a lower proportion of beta to theta waves than children without this condition.
Another brain test for ADHD includes what is known as quantitative electroencephalography or qEEG. qEEG for ADHD is very similar to NEBA in that it is also a measurement of the theta-to-beta brain wave ratio. This ratio is measured after one to two minutes of electroencephalography. This technology measures the activity of the brain in different regions with a process known as qEEG ADHD brain mapping. Relative to individuals without mental health conditions like schizophrenia, ADHD, depression, or substance use disorders, healthy individuals may have different activity levels in specific brain regions.
Another common test used to help diagnose ADHD is known as single-photon emission computed tomography or SPECT. SPECT imaging for ADHD involves injecting a radioactive dye into an individual’s bloodstream which allows medical professionals to visualize blood flow and brain activity. Generally, a person is injected and then asked to perform a specific task to assess brain function. Initially, this test may seem very appealing. However, there is quite a bit of controversy surrounding SPECT used in the diagnosis of ADHD. For example, SPECT is not a very accurate test and can only lead to a correct diagnosis about half of the time. Additionally, there are not enough research studies that determine that SPECT is actually a useful technique to understand brain differences in individuals with ADHD.
Limitations of ADHD Brain Scans
Every diagnostic test has limitations. Some tests have high sensitivity and specificity, while other tests have neither. ADHD brain scans are not incredibly sensitive — meaning that between individuals with ADHD, there will be many discrepancies or differences. Brain scans also generally look at individuals with ADHD and those without the condition without taking into account that many individuals have multiple mental health conditions or physical disorders. Thus, these scans are also not specific to ADHD. There is no way to standardize all the different types of brain scans into a cohesive knowledge base because the way each test is performed depends on the clinic.
A clinical examination is needed for a firm diagnosis of ADHD. Brain scans should only be used to verify an ADHD diagnosis but cannot confirm one when a clinical examination has not already been performed.
Hoogman, Martine; et al. “Subcortical brain volume differences of participants with ADHD across the lifespan: an ENIGMA collaboration.” The Lancet Psychiatry, April 2017. Accessed September 27, 2019.
Jacobson, Lisa; et al. “Anomalous Brain Development Is Evident in Preschoolers With Attention-Deficit/Hyperactivity Disorder.” J Int Neuropsychol Soc., July 2018. Accessed September 27, 2019.
The Mayo Clinic. “Adult attention-deficit/hyperactivity disorder (ADHD).” June 22, 2019. Accessed September 27, 2019.
Nuwer, Marc; Buchhalter, Jeffrey; Shepard, Katie. “Quantitative EEG in attention-deficit/hyperactivity disorder: A companion payment policy review for clinicians and payers.” Neurol Clin Pract., December 2016. Accessed September 27, 2019.
NEBA Health. “NEBA – FDA Cleared Brainwave ADHD Assessment Aid.” Accessed October 4, 2019.
Scheider, Howard, et. al. “Conventional SPECT Versus 3D Thresholded SPECT Imaging in the Diagnosis of ADHD: A Retrospective Study.” The Journal of Neuropsychiatry and Clinical Neurosciences, January 1, 2014. Accessed October 4, 2019.
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