Mapping the functional anatomy of sentence comprehension and application to presurgical evaluation of patients with brain tumor.
OBJECTIVE
The main clinical indication for functional MR imaging (fMRI) has been to preoperatively map the cortex. Motor paradigms to activate the cortex are simple and robust; however, language tasks show greater variability and difficulty. The aim of this study was to develop a language task with an adequate control task to engage the areas of the posterior temporal lobe responsible for sentence comprehension.


METHODS
We performed a cloze paradigm requiring silent reading of a visually presented sentence-completion task based on semantic meaning versus a letter-scanning epoch requiring the completion of nonlinguistic strings or a rest period. Before this task was clinically used in two patients epilepsy and cavernous angioma, its feasibility and accuracy were tested in 14 healthy right-handed participants.


RESULTS
Results showed significant activation of the posterior temporal cortex, including a broad area across the posterior left temporal cortex extending into the inferior parietal lobule. When the sentence completion-minus-letter string task was compared with the sentence completion-minus-rest task, increased activation was present in the posterior temporal lobe.


CONCLUSIONS
Decreased significant activation during the sentence completion-minus-rest contrast may be attributed to increased noise from intersubject variability in the rest period. Our results suggest that this task elucidates areas important to reading comprehension in the posterior and inferior temporal regions that verbal fluency and auditory discrimination tasks do not. Data from two cases are summarized to exemplify the input of this task for neurosurgery.
Ashtari
Manzar
M
Department of Radiology and Neurology, Long Island Jewish Division of the North Shore-Long Island Jewish Health System, New Hyde Park, New York, NY 11040, USA.
Perrine
Kenneth
K
Elbaz
Rania
R
Syed
Uzma
U
Thaden
Emily
E
McIlree
Carolyn
C
Dolgoff-Kaspar
Rima
R
Clarke
Tana
T
Diamond
Alan
A
Ettinger
Alan
A
D000328:Adult; D001931:Brain Mapping / Q000379:methods*; D001932:Brain Neoplasms / Q000473:pathology* / Q000503:physiopathology*; D032882:Comprehension; D005260:Female; D006801:Humans; D008297:Male; D011300:Preoperative Care; D011932:Reading