This article requires a subscription to view the full text. If you have a subscription you may use the login form below to view the article. Access to this article can also be purchased.
Abstract
Objective: Attention-deficit/hyperactivity disorder (ADHD) is a childhood-onset behavioral diagnosis in which children often fail to meet age norms in development of motor control, particularly timed repetitive and sequential movements, motor overflow, and balance. The neural substrate of this motor delay may include mechanisms of synaptic inhibition in or adjacent to the motor cortex. The primary objective of this study was to determine whether transcranial magnetic stimulation (TMS)–evoked measures, particularly short interval cortical inhibition (SICI), in motor cortex correlate with the presence and severity of ADHD in childhood as well as with commonly observed delays in motor control.
Methods: In this case-control study, behavioral ratings, motor skills, and motor cortex physiology were evaluated in 49 children with ADHD (mean age 10.6 years, 30 boys) and 49 typically developing children (mean age 10.5 years, 30 boys), all right-handed, aged 8–12 years. Motor skills were evaluated with the Physical and Neurological Examination for Subtle Signs (PANESS) and the Motor Assessment Battery for Children version 2. SICI and other physiologic measures were obtained using TMS in the left motor cortex.
Results: In children with ADHD, mean SICI was reduced by 40% (p < 0.0001) and less SICI correlated with higher ADHD severity (r = −0.52; p = 0.002). Mean PANESS motor development scores were 59% worse in children with ADHD (p < 0.0001). Worse PANESS scores correlated modestly with less SICI (r = −.30; p = 0.01).
Conclusion: Reduced TMS-evoked SICI correlates with ADHD diagnosis and symptom severity and also reflects motor skill development in children.
Footnotes
-
Study funding: Supported by NIH grant R01 MH078160.
-
- ADHD
- attention-deficit/hyperactivity disorder
- ADHD-RS-IV
- ADHD Rating Scale IV
- AMT
- active motor threshold
- CPRS
- Conners' Parent Rating Scale–Revised;
- CSP
- cortical silent period
- DSM-IV
- Diagnostic and Statistical Manual of Mental Disorders, 4th edition
- GABA
- γ-aminobutyric acid
- ICF
- intracortical facilitation
- MABC–2
- Motor Assessment Battery in Children version 2
- MEP
- motor evoked potential
- PANESS
- Physical and Neurological Examination for Subtle Signs
- RMT
- resting motor threshold
- SICI
- short interval cortical inhibition
- TD
- typically developing
- TMS
- transcranial magnetic stimulation.
-
Editorial, page 592
-
See page 622
-
Supplemental data at www.neurology.org
- Received April 14, 2010.
- Accepted September 21, 2010.
- Copyright © 2011 by AAN Enterprises, Inc.
AAN Members
We have changed the login procedure to improve access between AAN.com and the Neurology journals. If you are experiencing issues, please log out of AAN.com and clear history and cookies. (For instructions by browser, please click the instruction pages below). After clearing, choose preferred Journal and select login for AAN Members. You will be redirected to a login page where you can log in with your AAN ID number and password. When you are returned to the Journal, your name should appear at the top right of the page.
AAN Non-Member Subscribers
Purchase access
Letters: Rapid online correspondence
REQUIREMENTS
You must ensure that your Disclosures have been updated within the previous six months. Please go to our Submission Site to add or update your Disclosure information.
Your co-authors must send a completed Publishing Agreement Form to Neurology Staff (not necessary for the lead/corresponding author as the form below will suffice) before you upload your comment.
If you are responding to a comment that was written about an article you originally authored:
You (and co-authors) do not need to fill out forms or check disclosures as author forms are still valid
and apply to letter.
Submission specifications:
- Submissions must be < 200 words with < 5 references. Reference 1 must be the article on which you are commenting.
- Submissions should not have more than 5 authors. (Exception: original author replies can include all original authors of the article)
- Submit only on articles published within 6 months of issue date.
- Do not be redundant. Read any comments already posted on the article prior to submission.
- Submitted comments are subject to editing and editor review prior to posting.
