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
Background: Atypical language dominance is common in patients with temporal lobe epilepsy. We examined the association of left temporal hypometabolism with laterality of fMRI activation in a language task in a cross-sectional study.
Methods: Thirty patients with temporal lobe epilepsy (mean age 32.4 ± 11.0 years [range 18–55]; epilepsy onset 15.3 ± 11.3 years [range 0.8–40]; 22 left focus, 8 right focus) had 18fluoro-deoxyglucose (FDG)-PET using noninvasive cardiac input function. After MRI-based partial volume correction, regional glucose metabolism (CMRglc) was measured and asymmetry index, AI = 2(l − R)/(L + R), calculated. fMRI language dominance was assessed with an auditory definition decision paradigm at 3 T. fMRI data were analyzed in SPM2 using regions of interest from Wake Forest PickAtlas (Wernicke area [WA], inferior frontal gyrus [IFG], middle frontal gyrus [MFG]) and bootstrap laterality index, LI = (l − R/L + R).
Results: Nineteen patients had ipsilateral temporal hypometabolism; 3 of 4 patients with atypical language had abnormal FDG-PET. Increasing left midtemporal hypometabolism correlated with decreased MFG LI (r = −0.41, p < 0.05) and showed trends with WA LI (r = −0.37, p = 0.055) and IFG LI (r = −0.31, p = 0.099); these relationships became more significant after controlling for age at onset. Increasing hypometabolism was associated with fewer activated voxels in WA ipsilateral to the focus and more activated voxels contralaterally, but overall, activation amount in left WA was similar to subjects without left temporal hypometabolism (t = −1.39, p > 0.10).
Conclusions: We did not find evidence of impaired blood oxygenation level–dependent response in hypometabolic cortex. Regional hypometabolism appears to be a marker for the temporal lobe dysfunction that leads to displacement of language function.
Footnotes
-
Study funding: Supported by the Clinical Epilepsy Section, NINDS, NIH; Partnership for Pediatric Research Epilepsy Foundation (M.M.B.); and the Children's Research Institute Avery Award (M.M.B.). The contents are solely the responsibility of the authors and do not necessarily represent the official views of NIH.
-
Supplemental data at www.neurology.org
-
- AI
- asymmetry index
- AL
- atypical language
- BA
- Brodmann area
- BOLD
- blood oxygenation level–dependent
- CMRglc
- regional glucose metabolism
- FDG
- 18fluoro-deoxyglucose
- IFG
- inferior frontal gyrus
- LI
- laterality index
- LL
- left language
- MCD
- malformation of cortical development
- MFG
- middle frontal gyrus
- MTG
- middle temporal gyrus
- MTS
- mesial temporal sclerosis
- TLE
- temporal lobe epilepsy
- STG
- superior temporal gyrus
- WA
- Wernicke area
- Received May 21, 2010.
- Accepted December 22, 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.
