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: To evaluate possible abnormal increase in thalamic glutamate/glutamine levels for restless legs syndrome (RLS) indicating increased glutamatergic activity producing arousal that at night disrupts and shortens sleep.
Methods: 1H MRS of the right thalamus was performed using a 1.5 T GE MRI scanner and the PROBE-P (PRESS) on 28 patients with RLS and 20 matched controls. The Glx signal (combination of mostly glutamate [Glu] and glutamine [Gln]) was assessed as a ratio to the total creatine (Cr). This study tested 2 primary hypotheses: 1) higher thalamic Glx/Cr for patients with RLS than controls; 2) thalamic Glx/Cr correlates with increased wake during the sleep period.
Results: The Glx/Cr was higher for patients with RLS than controls (mean ± SD 1.20 ± 0.73 vs 0.80 ± 0.39, t = 2.2, p = 0.016) and correlated significantly with the wake time during the sleep period (r = 0.61, p = 0.007) and all other RLS-related polysomnographic sleep variables (p < 0.05) except for periodic leg movements during sleep (PLMS)/hour.
Conclusions: The primary findings introduce 2 new related dimensions to RLS: abnormalities in a major nondopaminergic neurologic system and the arousal disturbance of sleep. The strong relation of the arousal sleep disturbance to glutamate and the lack of relation to the PLMS motor features of RLS contrasts with the reverse for dopamine of a limited relation to arousal sleep disturbance but strong relation to PLMS. Understanding this dichotomy and the interaction of these 2 differing systems may be important for understanding RLS neurobiology and developing better treatments for RLS.
GLOSSARY
- Cho=
- choline-containing compounds;
- Cr=
- creatine/phosphocreatine;
- Gln=
- glutamine;
- Glu=
- glutamate;
- Glx=
- glutamine plus glutamate;
- 1H MRS=
- proton magnetic resonance spectroscopy;
- mI=
- myo-inositol;
- NAA=
- N-acetylaspartate;
- PLMS=
- periodic leg movements during sleep;
- PSG=
- polysomnography;
- RLS=
- restless legs syndrome;
- SWS=
- slow-wave sleep;
- VMB=
- ventral midbrain;
- WDSP=
- wake during the sleep period
Footnotes
Go to Neurology.org for full disclosures. Funding information and disclosures deemed relevant by the authors, if any, are provided at the end of the article.
Editorial, page 2006
- Received November 5, 2012.
- Accepted in final form January 24, 2013.
- © 2013 American Academy of Neurology
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
- Thalamic glutamate/glutamine in restless legs syndrome: Increased and related to disturbed sleep
- Potential effects of comorbid anxiety?
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.
