Table 2. Imaging and Findings.
| Study | Imaging | Imaging task | Principle Findings |
| Simos et al., 2002 | MSI, Pre/Post | Pseudoword rhyme-matching | Pre-intervention underactivation of left posterior STG in RD group increased to level of controls at post-intervention. Control group did not change over time. Additionally, RD showed pre-intervention overactivation of R STG. |
| Aylward et al., 2003 | fMRI, Pre/Post | Letter-Phoneme Matching (with Letters Only Matching control task) Comes From Morpheme Mapping (with Synonym Judgment control task) | Pre-treatment RD underactivated in L MFG, IFG, MTG, ITG, R SFG, and bilateral superior parietal regions during phoneme mapping and in L MFG, R superior parietal and fusiform/occipital area during morpheme mapping. No differences between groups at post-scan due to increased activity for RD group and decreased activity for controls. |
| Temple et al., 2003 | fMRI, Pre/Post | Rhyme Letters (phonological), Match Letters (nonphonological), Match Lines (nonletter) | Following treatment, RD had increased activity in L IFG, anterior cingulate, ITG, MTG/angular, hippocampal, and lingual gyri, R anterior cingulate, MFG, insula/IFG, SFG, MTG, posterior cingulate/precuneus, parieto-occipital sulcus, and bilateral anterior thalamus. These increases were not present in CT. |
| Eden et al., 2004 | fMRI, Pre/Post | Sound Deletion (aurally presented words), Word Repetition (aurally presented) | Post intervention, Group × Session interaction revealed increases in L IPL (BA 4 0), intraparietal sulcus (BA 40/7), fusiform/parahippocampal gyrus (BA 37), hippocampal gyrus, thalamus, and MFG (BA 46), R posterior STS/G (BA 22/39), SPL (BA 7), IPL (BA 40), IFG (45/46), inferior postcentral gyrus (BA 43), medial frontal cortex (BA 10/11/47), and inferior MFG (BA 11). |
| Shaywitz et al., 2004 | fMRI, Pre/Post/1yr follow-up | Matching Letter Name (audio) to Letter (visual), Audio tone/Visual symbol control task | Immediately following treatment, RD experimental intervention group showed increased activation compared to RD community intervention in L IFG and MTG and decreased activation in the R caudate nucleus. One year after treatment ended, the RD experimental intervention group had increased activation in bilateral IFG, LSTS, posterior MTG/ITG/anterior middle occipital gyrus, inferior occipital gyrus, and lingual gyrus, and decreased activation in R MTG and caudate nucleus. |
| Simos et al., 2005 | MSI, Pre/Post | Letter-sound naming, pseudoword reading | Grade × Group interactions revealed reduction in onset latency in the bilateral occipito-temporal region and increased onset latency in the L IFG for responders. |
| Richards et al., 2006 | fMRI | Orthographic mapping, Morpheme mapping with/without phonological shift, Phoneme mapping | Following intervention, the orthographic treatment group showed increased activation in R IFG and posterior parietal region to levels that no longer differed from control group. |
| Hoeft et al., 2007 | fMRI (and VBM) | Real-word rhyme judgment | Combining fMRI and VBM with behavioral scores predicted word attack skills better than behavioral or imaging alone. Regions predicting posttest word decoding scores included R fusiform gyrus, fusiform/mid occipital gyrus, and LMTG as positive predictors and R MFG as a negative predictor. |
| Richards et al., 2007 | fMRI, Pre/Post | Pseudoword visual decoding, aural match, and aural repeat | Following intervention, Group x Time interaction for visual-decode/aural-match contrast showed nonphonological group increased activation in L occipital cortex (BA 19) to the level of CT, whereas phonological group continued to underactivate. The aural-repeat/aural-match contrast revealed decreased activation for the phonological group to levels resembling CT in L SMG and postcentral gyrus |
| Simos, Fletcher, Sarkari, Billingsley-Marshall et al., 2007 | MEG, Pre/Mid/Post | Timed reading of increasingly difficult words | Changes included increased degree of activity in bilateral posterior MTG (BA 21), decreased onset latency in LMTG (BA 21) and R lateral occipitotemporal region (BA 19/37), and increased onset latency in premotor cortex. |
| Simos, Fletcher, Sarkari, Billingsley, et al., 2007 | MEG, Pre/Mid/Post | 3-letter pronounceable nonwords (visually presented) | No notable activation differences between responders and nonresponders at baseline. Following intervention, responders showed increased duration of activity in the L posterior STG, SMG, and angular gyrus. The nonresponders showed increased duration of activity in R temporoparietal and bilateral frontal areas. Responders showed changes in the sequence of activation to more closely resemble CT by initiating in extrastriate, followed by temporoparietal, and then frontal areas and this temporal profile was not apparent in nonresponders. |
| Meyler et al., 2008 | fMRI, Pre/Post/1yr Followup | Visual presentation of sentences with sense-nonsense judgment | Pre-intervention, RD underactivated in L mid occipital/angular, IPL/postcentral, SPL/sup occipital, MFG, R IPL/SMG, SMG/IPL and overactivated in anterior and posterior SMA. Post-treatment, RD activated more than CT in L putamen and R insula/IFG and CT were greater than RD in L SPL/superior occipital and MFG. At follow-up the treatment group showed greater activation than CT in L postcentral gyrus, insula/putamen, insula, SFG/cingulate, anterior SFG, anterior and middle cingulate, thalamus, and cerebellum (vermis), R postcentral gyrus, putamen/insula, SFG/SMA, anterior cingulate, posterior cingulate, precuneus, and cerebellum (vermis). |
| Odegard et al., 2008 | fMRI, Post | Phoneme-grapheme matching, tone-symbol | Following treatment, L inferior parietal showed increased activation in controls relative to non-responders, R inferior frontal showed greater activation in responders relative to non-responders and controls, R middle temporal showed greater activation in non-responders relative to responders and controls |
| Richards & Berninger, 2008 | fMRI, Pre/Post | Phoneme Mapping | Before treatment, children with dyslexia showed higher functional connectivity than controls from L IFG to bilateral MFG and SMA, L precentral gyrus, and R SFG. Following treatment, RD showed no difference from controls in L IFG seed point. |
| Davis et al., 2011 | fMRI, Post | Letter-sound matching | Responders showed greater activation in the L STG (BA 22) relative to nonresponders. Responders activated more that controls in L MTG/Angular (BA39) |
| Farris et al., 2011 | fMRI, Post | Phoneme-grapheme matching, tone-symbol | Following treatment, responders were equivalent to controls in functional connectivity between L and R inferior frontal lobes, and nonresponders exhibited less functional connectivity. |
| Hoeft et al., 2011 | fMRI (and DTI), Pre | Rhyme judgment | fMRI activity in the R IFG (BA 44, inferior operculum) together with DTI of the R superior longitudinal fasciculus predicted responsiveness with 72% accuracy. Whole-brain multivariate patterns of brain activation (fMRI) predicted reading gains with >90% accuracy. Areas contributing to classification with positive correlation: R IFG (operculum), insula, lingual gyrus, precuneus/MTG/occipital, culmen of cerebellum, L IFG (triangularis), SFG, MFG. Negative correlation: L IFG/Insula, precentral gyrus, SFG/SMA, IPL, posterior cingulate/cuneus/calcarine, L superior/middle occipital gyri, L midbrain, R lingual/fusiform |
| Rezaie et al., 2011a | MEG, Pre | Word reading | At baseline, adequate responders showed increased activity in the L MTG, L STG, L ventral occipitotemporal regions, and R medial temporal cortex relative to inadequate responders. Activity in these regions predicted improvement in real word reading efficiency above predictions of reading accuracy or fluency. |
| Rezaie et al., 2011b | MEG, Pre | 3-letter pronounceable nonwords | Pre-intervention activity was higher for adequate responders compared to inadequate responders in L SMG and angular gyrus and bilateral STG and MTG. Pre-intervention activity in L SMG, STG, and angular gyrus was positively correlated with post-intervention gains in fluency scores. |
| Yamada et al., 2011 | fMRI, Pre/Post | One-back task with letters and letter-like stimuli | Pre-treatment at-risk group underactivated in L ITG, superior lateral occipital cortex, and thalamus, R SFG, anterior cingulate, posterior superior STG, and temporal/fusiform cortex, occipital pole, and amygdala, bilateral IFG, frontal orbital cortex (ORB), MTG, SMG, precentral cortex, SPL, supracalcarine cortex, and putamen. The at-risk group overactivated in R frontal orbital cortex (medial to the underactivation listed above). Posttreatment the at-risk group overactivated in L IFG, frontal pole, SPL, and occipital pole, R SFG, SMG, ACC, MFG, planum temporale, frontal operculum, precuneus, postcentral gyrus, lateral occipital cortex, and lingual gyrus and bilateral precentral gyrus and paracingulate region and underactivated in L superior lateral occipital cortex. |
| Gebauer, Fink, Kargl et al., 2012 | fMRI, Pre/Post | Correctly spelled words, misspelled words, pseudowords | Treatment group showed increased activation following treatment in R posterior cingulate, L MTG, ITG, hippocampus, and parahippocampal region during pseudoword reading. The waiting group showed increases in R lateral occipital cortex and middle temporal cortex during all three conditions. CT showed increases in bilateral middle temporal and occipito-temporal regions. Group × Session interaction revealed increased activation for the training group in the bilateral parahippocampal area and cerebellum. The waiting group showed increased activation in bilateral precuneus and cerebellum, L frontal pole, and R lateral occipital cortex and parieto-temporal region. |
| Bach et al., in press | fMRI (and ERP), at Post-training used for predicting reading 2 years later | Word/symbol processing | fMRI and ERP data combined with behavioral measures at kindergarten significantly improved prediction of reading skill at second grade over behavioral measures alone. For fMRI, activity in L visual word form area (fusiform) ROI correlated with gains in letter knowledge. |
Note. The terms overactivated and underactivated are used in reference to control groups. MSI = magnetic source imaging which combines MEG with MRI, ERP = event related potential determined with electroencephalography, IFG = inferior frontal gyrus, MFG = middle frontal gyrus, SFG = superior frontal gyrus, STG = superior temporal gyrus, STS = superior temporal sulcus, MTG = middle temporal gyrus, ITG = inferior temporal gyrus, SMG = supramarginal gyrus, IPL = inferior parietal lobule, SPL = superior parietal lobule, SMA = supplementary motor area, ACC = anterior cingulate cortex.