Faculty Articles
EEG responses to low-level chemicals in different age groups and cacosmics
Document Type
Article
Publication Title
Toxicology and Industrial Health
ISSN
0748-2337
Publication Date
1-1-1994
Abstract
Recent studies from the University of Arizona indicate that normal subjects, both college students and the elderly, can register the presence of low-intensity odors in the electroencephalogram (EEG) in the absence of conscious awareness of the odors. The experimental paradigm involves subjects sniffing pairs of bottles, one containing an odorant (e.g. isoamyl acetate) dissolved in an odorless solvent (water or liquid silicone), the other containing just the solvent, while 19 channels of EEG are continuously recorded. For the low-intensity odor conditions, concentrations are adjusted downward (decreased) until subjects correctly identify the odor bottle at chance (50%). The order of odorants, concentrations, and hand holding the control bottle, are counterbalanced within and across subjects. Three previous experiments found that alpha activity (8-12 hz) decreased in midline and posterior regions when subjects sniffed the low-intensity odors. The most recent study suggests that decreased theta activity (4-8 hz) may reflect sensory registration and decreased alpha activity may reflect perceptual registration. In a just completed experiment involving college students who were selected based on combinations of high and low scores on a scale measuring cacosmia (chemical odor intolerance) and high and low scores on a scale measuring depression, cacosmic subjects (independent of depression) showed greater decreases in low-frequency alpha (8-10 hz) and greater increases in low-frequency beta (12-16 hz) to the solvent propylene glycol compared to an empty bottle. Topographic EEG mapping to low-intensity odorants may provide a useful tool for investigating possible increased sensitivity to specific chemicals in chemically sensitive individuals.
Volume
10
First Page
633
Last Page
643
NSUWorks Citation
Schwartz, G.,
Bell, I.,
Dikman, Z.,
Fernandez, M.,
Kline, J.,
Peterson, J.,
Wright, K.
(1994). EEG responses to low-level chemicals in different age groups and cacosmics. Toxicology and Industrial Health, 10, 633-643.
Available at: https://nsuworks.nova.edu/cps_facarticles/1094
