Research
New Faculty Collaborative Research Publications from the Creative Design & Data Science Center – Dr. Akitoshi Seiyama
Dr. Akitoshi Seiyama, Specially Appointed Professor and Director of AIU’s Creative Design & Data Science Center, co-authored four journal articles as described below.
A High-Accuracy and Easy-Use Differential Diagnosis Method of Bipolar Disorder Depressive Phase and Major Depressive Disorder Using a Wearable Near-Infrared Spectroscopy.
Authors: Yuji Sasaki, Koichi Ishizu, Akitoshi Seiyama, Naozo Sugimoto
Published in: Bipolar Disorders
Abstract
Objectives
Although conventional multichannel near-infrared spectroscopy (cNIRS) has been reported to be useful in differentiating bipolar disorder depressive phase (BDD) from major depressive disorder (MDD), its utilization in real clinical practice remains limited. The objective of this study was to evaluate the performance of wearable NIRS (wNIRS), which is cheaper to install and easier to use than cNIRS, in differentiating between BDD and MDD, and to propose an optimal index for wNIRS.
Methods
The subjects were 16 BDD patients, 16 MDD patients, and 16 healthy controls. Changes in the total hemoglobin signal (Δ[total-Hb]) in the bilateral frontal cortex during a 60 s verbal fluency task (VFT) were measured using the HOT-2000, a wNIRS capable of reducing noise from skin blood flow. In addition to evaluating the discriminative performance of the integral and centroid values proposed in previous studies, the ratio of the mean values of the Δ[total-Hb] during the first 20 s and subsequent 40 s (20–40 ratio) during the VFT was also employed and assessed.
Results
Only the 20–40 ratio showed significant differences between BDD and MDD, whereas the integral and centroid values did not. Using a cut-off value of 2.00 for the 20–40 ratio, the sensitivity and specificity of the BDD diagnosis were 100% and 93.4%, respectively.
Conclusions
The wNIRS measurements and the 20–40 ratio of the Δ[total-Hb] in the forehead area enabled more accurate differentiation between MDD and BDD than the conventional analysis.
View the full text (open source) here.
Attenuated parasympathetic modulation during “Wake to Sleep” and “Sleep to Wake” in high-neuroticism young adults: a heart rate variability study.
Authors: Kentaro Taniguchi*, Akitoshi Seiyama
*Visiting researcher at AIU’s Creative Design & Data Science Center
Published in: Bulletin of the National Research Centre
Abstract
Background
Neuroticism, characterized by emotional instability and heightened stress sensitivity, has been associated with sleep disturbances and altered autonomic nervous system regulation. However, its impact on dynamic parasympathetic modulation during sleep–wake transitions defined here as periods immediately surrounding sleep onset and morning waking remains unclear.
Methods
Healthy young adults (62 men and 49 women) were classified into a control or neuroticism group based on Kudo’s two-dimensional discriminative chart for the Cornell Medical Index. Participants in Groups I–II were assigned to the control group (n = 99), and those in Groups III–IV to the neuroticism group (n = 12). Heart rate variability (HRV) was measured using a portable electrocardiographic, and parasympathetic activity was indexed by normalized high-frequency component (HFnu). Two transition-based indices were calculated: ΔSleepOnset, (HFnu during the 90 min after minus before sleep onset) and ΔWake (HFnu during the 90 min after minus before waking).
Results
Both ΔSleepOnset and ΔWake were significantly smaller in the neuroticism group (ΔSleepOnset: p = 0.040, d = 0.20; ΔWake: p = 0.041, d = 0.20), whereas average HFnu during the entire sleep period did not differ significantly between groups (p = 0.28, d = 0.10). The same pattern was observed when analysing Group III alone, although statistical power was limited by the small size of Group IV.
Conclusions
Despite comparable overall parasympathetic activity during sleep, neuroticism group exhibits blunted parasympathetic modulation at sleep–wake transitions, reflecting reduced autonomic flexibility. Transition-based HRV indices such as ΔSleepOnset and ΔWake may serve as sensitive physiological markers of sleep vulnerability associated with neurotic traits.
View the full text (open source) here.
An approach to in vivo low-magnification optical coherence tomography for selective monitoring of tissue glucose concentration
Authors: Akitoshi Seiyama, Fengcheng Wei, Masato Ohmi
Published in: MethodsX
Abstract
The low-magnification optical coherence tomography (LM-OCT) is expected to enable the quantification of tissue glucose concentration (TGC) by maintaining high spatial resolution while reducing artifacts caused by tissue heterogeneity. In the present study, we report the practical application of LM-OCT using a conventional OCT system, i.e., without compromising spatial resolution, for the selective monitoring of changes in TGC through in vivo experiments using a hairless rat model.
A commercially available high-spatial resolution OCT device with a center wavelength of 1300 nm was used to detect the three-dimensional (3D) skin surface structure and the scattering coefficient related to the OCT slope.
The grand-averaged OCT signal was employed to estimate the OCT slope, while the original high-resolution OCT signals were used to reconstruct the 3D-structural image.
A strong linear correlation was observed between changes in the OCT slope and that in TGC, but not with 2-deoxy-glucose, lactate, or Intralipos (soybean oil).
View the full text (open source) here.
Cerebral Blood Flow Changes in Prefrontal Cortex During the Process of Landscape Evaluation: A NIRS Study
Authors: Junya Matsumoto, Keijiro Yamada, Akitoshi Seiyama, Masashi Kawasaki
Published in: Japanese Journal of JSCE
Abstract
This study focuses on the evaluation process of landscape based on the theory of emotion by using Near-Infrared Spectroscopy. The aim of this study is to show the trend of cerebral blood flow (CBF) changes corresponding to pleasant and unpleasant emotion in prefrontal cortex during viewing landscape pictures, and to find the temporal correlation between CBF changes and landscape evaluation using semantic differential method. Results showed (1) pleasant pictures led to a decrease of oxygenated hemoglobin concentration in the late phase of presentation, while unpleasant pictures led to an increase in the early and middle phase, (2) the concentration changes mainly correlated with the evaluation score of “orderly/open/lively” in the early phase, while “orderly/clean/beautiful/soft/warm/historic” in the middle and late phase. These findings suggest landscape pictures also induce CBF changes corresponding to each emotion, and CBF changes occur in relation to arousal or activity, valence or evaluation, and other emotional traits in this order.