Near-infrared spectroscopy analysis of frontal lobe dysfunction in schizophrenia.
BACKGROUND
Previous studies have shown that near-infrared spectroscopy (NIRS) has high temporal resolution, requires little restraint, and is suitable for examining the effect of psychological tasks on brain circulation. In the present study, frontal function in schizophrenic patients was analyzed by NIRS during random number generation (RNG), ruler-catching (RC), and sequential finger-to-thumb (SFT) tasks.


METHODS
Two sets of NIRS probes were attached to the foreheads of 13 schizophrenic patients and 10 control subjects approximately at Fp1-F7 and Fp2-F8. Near-infrared spectroscopy was conducted at a sampling rate of 1 Hz, with the pathlength being determined by time-resolved spectroscopy with differential pathlength factor measurements. The absolute changes in oxygenated (oxy-Hb) and deoxygenated (deoxy-Hb) hemoglobin concentrations in response to each task were measured, and total hemoglobin (total-Hb) concentration was calculated as the sum of the two.


RESULTS
During RNG task, total- and oxy-Hb concentrations increased, and deoxy-Hb decreased, but the responses were significantly smaller in schizophrenic patients. During RC task, oxy-Hb in schizophrenic patients tended to decrease, in contrast to the mostly increasing response in control subjects. No group difference was observed during SFT task.


CONCLUSIONS
Task-dependent profile of functional abnormalities was observed in schizophrenic frontal brain metabolism. These results support the usefulness of NIRS data in investigating frontal lobe dysfunction and evaluating psychopathologic condition in schizophrenic patients.
Shinba
Toshikazu
T
Department of Stress Disorders Research and Integrative Neuroscience, Tokyo Institute of Psychiatry, Tokyo, Japan.
Nagano
Mitsuru
M
Kariya
Nobutoshi
N
Ogawa
Kazuo
K
Shinozaki
Takiko
T
Shimosato
Seiji
S
Hoshi
Yoko
Y
D000161:Acoustic Stimulation; D000328:Adult; D001931:Brain Mapping; D016022:Case-Control Studies; D002560:Cerebrovascular Circulation; D004553:Electric Conductivity; D005260:Female; D005625:Frontal Lobe / Q000002:abnormalities* / Q000098:blood supply; D007839:Functional Laterality; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000378:metabolism; D010108:Oxyhemoglobins / Q000378:metabolism; D011930:Reaction Time; D012559:Schizophrenia / Q000175:diagnosis / Q000378:metabolism / Q000473:pathology*; D012867:Skin / Q000503:physiopathology; D019265:Spectroscopy, Near-Infrared / Q000379:methods*; D013223:Statistics as Topic; D014705:Verbal Behavior
D006454:Hemoglobins; D010108:Oxyhemoglobins; D010100:Oxygen