Effects of a Phonologically Driven Treatment for Dyslexia on Lactate Levels Measured by Proton MR Spectroscopic Imaging
Todd L. Richards
,a,
David Corinaa,
Sandra Serafinia,
Keith Steurya,
Denise R. Echelarda,
Stephen R. Dagera,
Ken Marroa,
Robert D. Abbotta,
Kenneth R. Maravilla anda and
Virginia W. Berningera
a From the Departments of Radiology (T.L.R., S.R.D., K.M., D.R.E., K.R.M.), Psychiatry and Behavioral Science (S.R.D.), Psychology (D.C., K.S.), Speech and Hearing Sciences (S.S.), and Bioengineering (T.L.R., S.R.D.) and the College of Education (R.D.A., V.W.B.), University of Washington, Seattle, WA.
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FIG 1. Bar graph of the number of average activated voxels (as defined by MR spectroscopy lactate increases) in the left anterior brain quadrant for both dyslexic and control participants. Within each graph, the data on the left were obtained before treatment, and the data on the right were obtained after treatment. Error bars indicate the standard error of the mean. The asterisk indicates dyslexic versus control comparisons that were significantly different. The data were collected using 4000/272 proton echo-planar spectroscopic imaging. A, Data obtained during the phonologic task from the left anterior brain. B, Data obtained during the lexical access task also from the left anterior brain region
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FIG 2. MR image and proton spectra from an activated brain region of one dyslexic participant. The spectroscopic data were collected using 4000/272 proton echo-planar spectroscopic imaging. The MR image was collected using a 2000/80 fast spin-echo pulse sequence. The intensity axis of the spectra is scaled so that the lactate can be visualized more easily; however, choline and NAA are scaled off the figure. Note the decrease in the lactate peaks for the posttreatment spectrum. Cho, choline; CR, creatine. A, MR image with white box indicating the brain region measured with MR spectroscopy. B, Proton MR spectrum from the white box brain region before treatment (the lactate resonance has a signal-to-noise ratio of 2.2). C, Proton MR spectrum from the white box brain region after treatment (lactate has a signal-to-noise ratio of 1.6).
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FIG 3. Proton MR spectra and image from a dyslexic boy before treatment during the phonologic task. A, Spectrum from voxel 7 shows choline (CHO), creatine (Cr), NAA, and lactate. B, Nine spectra from nine adjacent voxels (position is shown in D), zoomed into the NAA region (1.7-2.3 ppm). C, Nine spectra from nine adjacent voxels, zoomed into the lactate region (1.10-1.33 ppm). The vertical scale of this set was increased six times higher than the NAA set so that lactate could be easily visualized. An increase in lactate can be clearly seen in voxels 6 through 8 compared with voxels 1 through 4. D, MR image shows the location of the nine voxels shown in A through C.
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FIG 4. Example of normalized lactate metabolite images of the left frontal region of the brain from a dyslexic boy before and after treatment. The data were collected using 4000/272 proton echo-planar spectroscopic imaging. A, Normalized lactate image from the left anterior quadrant of the section shown in the MR image of a dyslexic boy created from the proton echo-planar spectroscopic imaging spectra before the phonologically driven instructional treatment. B, Image obtained after treatment. C, MR image shows the middle slice of the proton echo-planar spectroscopic imaging anatomic section location. The white box on the MR image shows the area that is displayed in the lactate images. This is the brain region that had a significant difference between dyslexic and control groups. The lactate was normalized according to this equation: (lactate/NAA)phonologic - (lactate/NAA)passive
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