Determination of language dominance with near-infrared spectroscopy: comparison with the intracarotid amobarbital procedure.
OBJECTIVE
To determine the efficacy of near-infrared spectroscopy (NIRS) in identifying the hemisphere associated with language by measuring changes in bilateral lateral inferior frontal blood flow during a word generation task in epilepsy surgery patients and healthy volunteers.


METHODS
Sixteen patients who underwent the intracarotid amobarbital procedure (IAP) and eight healthy right-handed/right-footed individuals were tested with NIRS during a word generation paradigm.


RESULTS
Increases in lateral inferior frontal total hemoglobin concentrations agreed with the IAP in 11 of 16 patients, including 2 of 3 with right hemisphere (atypical) speech dominance (P = 0.13). NIRS revealed increases in lateral inferior frontal total hemoglobin concentrations congruent with language dominance predicted by handedness/footedness in 18 of 24 subjects, including 100% of healthy right-handed subjects (P = 0.02).


CONCLUSIONS
NIRS is a simple, non-invasive, safe modality for measuring cerebral blood flow. Further research and development of testing procedures and instrumentation are needed before routine implementation in pre-surgical testing.
Watson
Nathaniel F
NF
Department of Neurology, University of Washington Regional Epilepsy Center, Box 359745, 325 Ninth Avenue, Seattle, WA 98104-2499, USA. nwatson@u.washington.edu
Dodrill
Carl
C
Farrell
Don
D
Holmes
Mark D
MD
Miller
John W
JW
D000328:Adult; D000654:Amobarbital / Q000493:pharmacokinetics; D001921:Brain / Q000502:physiology*; D002339:Carotid Arteries; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D018757:GABA Modulators / Q000493:pharmacokinetics; D006801:Humans; D007802:Language; D008297:Male; D008875:Middle Aged; D011897:Random Allocation; D019265:Spectroscopy, Near-Infrared / Q000379:methods*
D018757:GABA Modulators; D000654:Amobarbital