Dyslexia-specific brain activation profile becomes normal following successful remedial training.
OBJECTIVE
To examine changes in the spatiotemporal brain activation profiles associated with successful completion of an intensive intervention program in individual dyslexic children.


METHODS
The authors obtained magnetic source imaging scans during a pseudoword reading task from eight children (7 to 17 years old) before and after 80 hours of intensive remedial instruction. All children were initially diagnosed with dyslexia, marked by severe difficulties in word recognition and phonologic processing. Eight children who never experienced reading problems were also tested on two occasions separated by a 2-month interval.


RESULTS
Before intervention, all children with dyslexia showed distinctly aberrant activation profiles featuring little or no activation of the posterior portion of the superior temporal gyrus (STGp), an area normally involved in phonologic processing, and increased activation of the corresponding right hemisphere area. After intervention that produced significant improvement in reading skills, activity in the left STGp increased by several orders of magnitude in every participant. No systematic changes were obtained in the activation profiles of the children without dyslexia as a function of time.


CONCLUSIONS
These findings suggest that the deficit in functional brain organization underlying dyslexia can be reversed after sufficiently intense intervention lasting as little as 2 months, and are consistent with current proposals that reading difficulties in many children represent a variation of normal development that can be altered by intensive intervention.
Simos
P G
PG
Vivian L. Smith Center for Neurologic Research, Department of Neurosurgery, University of Texas-Houston Health Science Center, 77030, USA. psimos@uth.tmc.edu
Fletcher
J M
JM
Bergman
E
E
Breier
J I
JI
Foorman
B R
BR
Castillo
E M
EM
Davis
R N
RN
Fitzgerald
M
M
Papanicolaou
A C
AC
D000293:Adolescent; D001289:Attention Deficit Disorder with Hyperactivity / Q000523:psychology; D001931:Brain Mapping; D002648:Child; D004410:Dyslexia / Q000000981:diagnostic imaging / Q000503:physiopathology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D011877:Radionuclide Imaging; D011932:Reading; D012073:Remedial Teaching; D014888:Wechsler Scales