Tottori J. Clin. Res. 7(1), 21-25, 2016

Evaluation of the peripheral blood hemoglobin concentration
and brain activity-Using optical topography (feature values)Michiyo Yamamoto,1)* Tsuruhei Sukegawa2)
1） Department of Medical Laboratory, NHO Tottori Medical Center2) Department of Psychiatry, NHO Tottori Medical Center*Correspondence: 876 Mitsu, Tottori 689-0203, Japan
Abstract
Optical topography has attracted attention as an examination method for visualizing brain activity. In thismethod, the head is irradiated with near-infrared light, and the hemoglobin absorption in the brain tissue ismeasured, which allows the mapping and visualization of brain activity. We gave tasks to patients, andevaluated changes in near-infrared ray absorption, i.e., changes in the oxyhemoglobin concentration in the local
brain tissue using optical topography, and determined whether the oxyhemoglobin concentration as a parameterof brain activity is affected by the peripheral blood hemoglobin concentration. As a result, there was no
significant correlation between the peripheral blood hemoglobin concentration and changes in theoxyhemoglobin concentration due to the tasks. These results suggest that the numerical expression of brain
activity is possible using optic topography without being affected by the peripheral blood hemoglobin
concentration. Tottori J. Clin. Res. 7(1), 21-25, 2016
Key words: optical topography, near-infrared light, oxyhemoglobin, auxiliary diagnosis of depressive
symptoms, verbal fluency task
1. Introduction
In recent years, the number of patients withpsychiatric disorders has markedly increased, being
3,200,000 in 2011. In addition to cancer, stroke,
myocardial infarction, and diabetes mellitus,
psychiatric disorders are designated as one of the 5major diseases specified by the Ministry of Health,Labour and Welfare based on the Medical Care Act.
Mood disorders such as depression are diagnosed
mainly by a medical interview. Therefore, objective
diagnosis is difficult, and diagnosis is timeconsuming. However, previous studies have shown
differences in the pattern of changes in the brain
blood flow among psychiatric disorders. Optical
topography, which allows the visualization of brain
activity, is used as an auxiliary method for thedifferential diagnosis of depressive symptoms.
Optical topography is an examination method
in which the head is irradiated with near-infrared
light, and light that penetrates 2-3 cm deep from thescalp and is scattered and detected. Near-infrared
light readily passes through the body such as thebone and muscle, and its absorption differs

according to the amount of oxygen bound tohemoglobin in the local tissues. In optical
topography, from near-infrared ray absorption, theratio of oxyhemoglobin (oxy-Hb) to deoxyhemoglobin (deoxy-Hb) in the local brain tissue
and the total hemoglobin (total-Hb) as the sum ofoxy- and deoxy-Hb are calculated, and their values
in each brain area are mapped as a parameter ofbrain activity. This method, which allows thevisualization and numerical expression of brain
activity, has attracted attention in recent years1).
2. Subjects and Methods
The subjects consisted of 24 staff members (15males and 9 females; mean age, 40.9 ± 22.7 years)
who underwent a health checkup examination for
staff members in 2012, and volunteered to undergo
optical topography and 68 outpatients (31 malesand 37 females; mean age, 42.9 ± 34.8 years) who
visited the Department of Psychiatry in Hospital A
from April, 2012, and were examined by optical
topography (total, 92 subjects; 46 males and 46
females; mean age, 42.4 ± 32.0 years). Under1