Effects of a phonologically driven treatment for dyslexia on lactate levels measured by proton MR spectroscopic imaging

BACKGROUND AND PURPOSE: Dyslexia is a language disorder In which reading ab ility is compromised because of poor phonologic skills. The purpose of this study was to measure the effect of a phonologically driven treatment for d yslexia on brain lactate response to language stimulation as measured by pr oton MR spectroscopic imaging. METHODS: Brain lactate metabolism was measured at two different time points (1 year apart) during four different cognitive tasks (three language tasks and one nonlanguage task) in dyslexic participants (n = 8) and in control participants (n = 7) by using a fast MR spectroscopic imaging technique cal led proton echo-planar spectroscopic imaging (1 cm(3) voxel resolution). Th e age range for both dyslexic and control participants was 10 to 13 years. Between the first and second imaging sessions, the dyslexic boys participat ed in an instructional intervention, which was a reading/science workshop. RESULTS: Before treatment, the dyslexic boys showed significantly greater l actate elevation compared with a control group in the left anterior quadran t (analysis of variance, P =.05) of the brain during a phonologic task. Aft er treatment, however, brain lactate elevation was not significantly differ ent from that of the control group in the left anterior quadrant during the same phonologic task. Behaviorally, the dyslexic participants improved in the phonologic aspects of reading. CONCLUSION: instructional intervention that improved phonologic performance in dyslexic boys was associated with changes in brain lactate levels as me asured by proton echo-planar spectroscopic imaging.