Normal activation of frontotemporal language cortex in dyslexia, as measured with oxygen 15 positron emission tomography.
OBJECTIVE
To assess the ability of dyslexic men to activate left middle to anterior language cortex normally.


METHODS
Positron emission tomography using oxygen 15-labeled water as a tracer during rest and during a syntax task involving sentence comprehension.


METHODS
Research hospital.


METHODS
Fifteen right-handed, severely dyslexic men (mean [+/- SD] age, 27 +/- 5 years) and 20 matched controls.


METHODS
None.


METHODS
Cerebral blood flow.


RESULTS
During rest, dyslexics showed reduced blood flow (relative to controls) in one left parietal region near the angular/supramarginal gyri, but otherwise normal flow. During syntactic processing, dyslexics and controls showed similar, significant activation of left middle to anterior temporal and inferior frontal cortex.


CONCLUSIONS
These results, together with the previously reported failure of dyslexics to activate left temporoparietal cortex during phonologic processing, argue for dysfunction of left cortical language areas restricted to posterior language regions in dyslexia.
Rumsey
J M
JM
Child Psychiatry Branch, National Institute of Mental Health, Bethesda, Md.
Zametkin
A J
AJ
Andreason
P
P
Hanahan
A P
AP
Hamburger
S D
SD
Aquino
T
T
King
A C
AC
Pikus
A
A
Cohen
R M
RM
D000328:Adult; D002560:Cerebrovascular Circulation; D004410:Dyslexia / Q000503:physiopathology*; D005625:Frontal Lobe / Q000000981:diagnostic imaging / Q000503:physiopathology*; D007839:Functional Laterality; D006801:Humans; D008297:Male; D010104:Oxygen Radioisotopes; D013702:Temporal Lobe / Q000000981:diagnostic imaging / Q000503:physiopathology*; D014055:Tomography, Emission-Computed; D014888:Wechsler Scales
D010104:Oxygen Radioisotopes