Effects of Color Temperature and Brightness on Electroencephalogram Alpha Activity in a Polychromatic Light-emitting Diode.
OBJECTIVE
It has been reported that working and learning efficiency might be increased through artificially controlling the color temperature and brightness of light. However, the neurological bases of these outcomes are not well established. Our study was designed to observe whether electroencephalogram (EEG) alpha frequency, as a candidate biological marker, demonstrates significant changes in response to alterations of specific light parameters.


METHODS
Thirty-two healthy subjects performed cognitive tasks under four different polychromatic light conditions: a combination of two different levels of color temperature (2766K vs. 5918K) and brightness (300 lux vs. 600 lux). Spectrum analyses were performed on alpha frequency.


RESULTS
Subjects reported that they felt more pleasant in bright conditions and more relaxed in warm color temperature conditions. Our findings indicate that alpha power increases in warm, low-light and cool, high-light conditions, and there is a significant interaction between color temperature and brightness.


CONCLUSIONS
EEGs might serve as a useful biological marker for further research related to the effects of polychromatic light on cognitive function.
Department of Psychiatry, Yonsei University College of Medicine, Seoul, Korea. ; Institute of Behavioral Science in Medicine, Yonsei University College of Medicine, Seoul, Korea.
Jin Young
JY
Park
Department of Psychiatry, Yonsei University College of Medicine, Seoul, Korea. ; Institute of Behavioral Science in Medicine, Yonsei University College of Medicine, Seoul, Korea.
Ra-Yeon
RY
Ha
Department of Psychiatry, Konyang University College of Medicine, Daejeon, Korea.
Vin
V
Ryu
Department of Psychiatry, Yonsei University College of Medicine, Seoul, Korea. ; Institute of Behavioral Science in Medicine, Yonsei University College of Medicine, Seoul, Korea.
Eosu
E
Kim
Department of Psychiatry, Yonsei University College of Medicine, Seoul, Korea. ; Institute of Behavioral Science in Medicine, Yonsei University College of Medicine, Seoul, Korea.
Young-Chul
YC
Jung
Alpha frequency; Brightness; Color temperature; Electroencephalogram; Polychromatic light