Table I.
Diffusion tensor imaging studies examining the brain‐behavior correlation with reading
| Participants | Reading group criteria/tests | DTI technique, index and ROI | Results | |
|---|---|---|---|---|
| Correlations | Group differences | |||
| Studies with Dyslexic or Poor Readers | ||||
| Klingberg et al.,2000 | ||||
| 5M and 1F PRs6M and 5F GRsAge: 26.1 yrs | PRs: >1 SD below sample M on WRMT‐R‐‐WITests: WRMT‐R–WA, WI | Tech: Voxel‐basedIndex: FA | 1) Positive: FA with WRMT‐R–(WA, WI) (in L TPR) | 1) FA: PRs < GRs (in bilateral TPR) |
| Deutsch et al.,2005 | ||||
| 6M and 1F PRs6M and 1F GRsAge: 10.7 yrs | PRs: ≤30th percentile on WJ‐BRCTests: CTOPP‐PA, PM, RN; WJ‐BRC, PC, RF, SP, WA, LWID | Tech: Voxel‐basedIndex: FA, CI, PDDROI: TPR | 1) Positive: FA with WJ‐(BRC, SP, WA, LWID) and CTOPP‐RN (in L TPR) 2) Positive: CI with WJ‐(BRC, SP, WA, LWID) and CTOPP‐RN (in L TPR) | 1) FA and CI: Good > poor readers in the L TPR2) PDD: GRs > PRs in sup‐inf direction; PRs > GRs in ant‐post direction |
| Niogi and McCandliss,2006 | ||||
| 8M and 3F DRs7M and 13F TRsAge: 8.1 yrs | DRs: 1 SD below sample M on WJ‐LWIDTests: WJ‐LWID, WA; WAIS; CTOPP‐DR | Tech: ROQS with manual elliptical validity checkIndex: FA, LATROI: CS, sup CR, sup LF, post IC, ant CR | 1) Positive: FA with WJ‐(WA, LWID) (in L sup CR)2) Positive: FA with WJ‐LWID (in L CS)3) Positive: FA with CTOPP‐DR (bilateral ant CR)4) Negative: FA with WJ‐LWID (LAT sup CR) | 1) FA: TRs > DRs (lat sup CR)2) FA: TRs > DRs (lat CS)3) FA: TRs > DRs (L sup CR, L CS) |
| Frye et al.,2008a | ||||
| 6M and 3F DRs12M and 6F TRsAge: 23.9 yrs | DRs history of RD diagnosisTests: CTONI; TOVA; CTOPP‐PA, APA, RN, ARN; WJ‐LWID, WA | Tech: Volume‐basedIndex: FA, ADROI: Splenium | 1) Negative: FA and AD with WJ‐LWID within each reading group2) Positive: FA with FA, RN; AD with PA, APA, ARN in TRs only | 1) FA and AD: DRs > TRs |
| Richards et al.,2008 | ||||
| Fathers with DR child;4 PRs7 GRsAge 30–5 yrs | PRs: 1 SD < WAIS‐R‐VIQTests: TOWRE; GORT‐RA, RR; RAN‐L, N;WIAT‐II‐SP, WM; WRAT 3‐SP; WRMT‐R–WA, WI | Tech: Voxel‐basedIndex: FA | 1) FA: TRs > DRs in bilateral precentral, inf F orb, sup OCC, fusiform, postcentral, inf P, inf T, in right sup F, mid F, inf F oper, inf F tri, supp motor area, cuneus, mid OCC, and in left lingual, sub P, pre‐cuneus, putamen, sup T | |
| Rollins et al.,2009 | ||||
| 16M and 3F DRs13M and 5F TRsM age = 10 yrs; | DRs: referral from a dyslexia remediation programTests: WJ‐ WA, LWID | Tech: Volume‐basedIndex: FA, AD, ADC, RDROI: SLF, IFO‐ILFPost IC | 1) Positive: FA and AD with age (in TRs, in IFO‐ILF, post IC)2) Positive: FA with age (in DRs in SLF Negative: RD with age (in TRs in SLF, IFO‐ILF, post IC)3) Negative RD with age (in DRs in SLF)4) Negative: RD with age (in TRs in SLF, IFO‐ILF, post IC)5) Negative: ADC with age (in TRs and DRs for all 3 ROIs)6) Negative: AD and age (in DRs in post IC) | 1) FA: TRs > DRs in IFO‐ILF and post IC until age 11 yrs. |
| Odegard et al.,2009 | ||||
| 5M and 5F DRs4M and 3F TRsAge = 12.3 yrs | DRs: referral by hospitalTests: DST‐PD; WIAT‐II‐BRC | Tech: Whole‐brain analysis using TBSSIndex: FA | 1) Positive: FA with DST‐PD (in L sup CR, L and R UF, and R IFO‐IFL)2) Negative: FA with DST‐PD (in L post CC)3) Positive: FA with WIAT‐II‐BRC (in L and R sup CR, L corticopontine tract, sup thalamic radiation, and R post IC)4) Negative: FA with WIAT‐II‐BRC (in L post CC) | |
| Rimrodt et al.,2009 | ||||
| 7M and 7F DRs9M and 8F TRsAge: 11 yrs | DRs: WJ‐WA or LWID < 25th percentile, WJ basic skills < 40th percentileTests: WJ‐WA, LWID; TOWRE; WIAT‐II | Tech: Voxel‐based, tractographyIndex: FAROIs: Limited to perisylvian network | 1) Positive: FA with TOWRE (in L IFG, precentral gyrus, FG, middle T gyrus) | 1) FA: TRs > DRs (IFG, left TPR), DRs > TRs (L insula,; R: FG, sup T G |
| Keller and Just2009 | ||||
| 35 DRs with treatment12 DRs no treatment25 TRs no treatmentAge: 8–12 yrs | DRs: recruited from Power4Kids Reading Initiative, TOWRE ≤ 30%, PPVT ≥ 5%Tests: WRMT‐R‐WA, WI; WJ‐PC; TOWRE‐PDE, SWE | Tech: Voxel‐basedIndex: FA, AD, RD | 1) Positive: FA across PRs and GRs with WRMT‐R WA2) Negative: RD across PRs and DRs with WRMT‐R WA3) Negative: RD with PDE in pre‐ vs. post‐remediated PRs4) Positive: FA and RD at L ant CS across PRs and GRs with PDE5) Negative: FA and RD at L ant CS across PRs and GRs with SWE | 1) FA: post‐remediated PRs > pre‐remediated PRs (peak in L ant and CS)2) RD: post‐remediated PRs < pre‐remediated DRs (peak in L ant and CS)3) FA: Pre‐remediated PRs < GRs |
| Studies without Dyslexic or Poor Readers | ||||
| Beaulieu et al.,2005 | ||||
| 14M and 18FAge = 11.1 yrs | Tests: WRMT‐R–WI | Tech: Voxel‐based, tractographyIndex: FA | 1) Positive: FA with WRMT‐R–WI (in L TPR) (cluster in post IC) | |
| Nagy et al.,2004 | ||||
| 14M and 9FAge = 11.9 yrs | Tests: Speed of reading aloud 20 Swedish words | Tech: Voxel‐basedIndex: FA | 1) Negative: FA with reading time (in single cluster of L T) | |
| Dougherty et al.,2007 | ||||
| 21 M, 28 FM age = 9.8 yrs | Tests: CTOPP‐PA, PM, RN; GORT IV‐RQ; WJ‐ PC, WA, LWID | Tech: Volume‐basedIndex: FA, RDROI: Parts of CC | 1) Negative: FA with CTOPP‐PA (in temporal‐callosal segment)2) Positive: RD with CTOPP‐PA (in temporal‐callosal segment) | |
| Qiu et al.,2008 | ||||
| 13M and 11F 1st grade, age 7.416M and 11F 4th grade, age 10.211M and 13F adult, age 22.8 yrs | Tests: Reading 200 Chinese characters and 200 English words | Tech: TBSS whole brain FA map with clusters where age groups differedIndex: FA, MD, RD, AD | After controlling for age:1) Negative: FA and RD with Chinese reading (in L ant IC)2) Negative: MD with English reading (in L and R CR) | 1) MD: 4th < 1st graders (clusters in EC, sup CR, C, T, OCC, and sup F)2) MD: Adults < 4th graders (in F, R ant T, CP, ant and post IC, and clusters in splenium)3) FA: 4th > 1st graders (clusters in L genu of IC, L CP)4) FA: Adults > 4th graders (in C, CP, mid and R post T, ant, post, and genu IC, ant EC, sup CR, cingulum and parts of F and P)5) RD: 4th < 1st graders (in L genu IC, L CP, and F)6) RD: Adults < 4th graders (in C, CP; R ant, mid, and post T; ant, genu, and post IC; ant EC; sup CR; cingulum; many parts of F)7) AD: 4th > 1st graders (clusters in CR and F)8) AD: adults < 4th graders (ant, mid, and post R T; L and R post IC; clusters in splenium; and many areas of F)9) AD: 4th < 1st graders (clusters in L C; L and R OCC; and L CR (AD: 4th < 1st graders (clusters in CR and F) |
Brain directions: ant, anterior; inf, inferior; L, left; post, posterior; R, right; sup, superior. Regions of interest (ROIs): CC, corpus callosum; CP, cerebral peduncles; CR, corona radiata; CS, centrum semiovale; EC, entorhinal cortex; F, frontal; FG, fusiform gyrus; hem, hemisphere; IC, internal capsule; IFG, inferior frontal gyrus; IFO‐ILF, inferior fronto‐occipital–inferior longitudinal fasciculus; LF, longitudinal fasciculusl; LG, lingual gyrus; OCC, occipital; orb, orbital; P, parietal lobe; SLF, superior longitudinal fasciculus; SFG, superior frontal gyrus; T, temporal lobe; TPR, temporo‐parietal region; UF, uncinate fasciculus. DTI measures: AD, axial diffusivity; CI, coherence index; FA, fractional anisotropy; PDD, principal diffusion direction; RD, radial diffusivity; ROQS, reproducible objective quantification scheme; TBSS, tract‐based spatial statistics. Participants (Ps): DRs, dyslexic readers; GRs, good readers; PRs, poor readers; TRs, typical readers. Reading tests: ARN, alternative rapid naming; BRC, basic reading comprehension; CTONI, comprehensive tests of nonverbal intelligence; CTOPP, comprehensive test of phonological processing; DR, digit recall; DST‐PD, decoding skills test‐phonological decoding; GORT, gray oral reading test third edition; IV‐RQ, fourth edition‐reading quotient; L, letters; LWID, letter word identification; N, numbers; PA, phonological awareness; APA, alternative phonological awareness; PC, passage comprehension; PDE, phonetic decoding efficiency; PM, phonological memory; RA, reading accuracy; RAN, rapid automatized naming; RF, reading fluency; RN, rapid naming; RR, reading rate; SP, spelling; SWE, sight word efficiency; TOVA, tests of variables of attention; TOWRE, test of word reading efficiency; WA, word attack; WAIS‐FSIQ, Wechsler abbreviated intelligence scale‐full scale IQ; WI, word identification; WIAT‐II, Wechsler individual achievement test‐second edition; WJ, Woodcock‐Johnson‐III‐tests of achievement; WM, working memory; WRAT 3‐SP, wide range achievement test‐third edition‐spelling; WRMT‐R‐, Woodcock reading mastery test‐revised. Statistical terms: M, mean; LAT, lateralization index; SD, standard deviation.