Combined Effects of Mental Load and Background Noise on CNS
Activity Indicated by Brain DC Potentials
M. Trimmel, M. Kundi, G. Binder, E. Groll-Knapp, and M.
Haider
Institute of Environmental Health, University of Vienna
Trimmel, M., Kundi, M., Binder, G., Groll-Knapp,
E., & Haider, M. (1996). Combined effects of mental load and background
noise on CNS activity indicated by brain DC potentials. Environment
International, 22, 83-92.
To assess combined effects of noise and mental load on brain activity,
DC potential shifts were evaluated. In a 3 x 2 x 3 x 5 repeated ANOVA design
with Type of Noise (music sound, white noise, street noise) x Noise Intensity
(no noise, 55dB[A], 75 dB[A]) x Mental Load (load vs. no load) x DC Recording
Location (F3, F4, Cz, P3, P4 versus linked mastoids) 2-min epochs of exposure
were analyzed in 18 subjects. Significant main effects were found for Type
of Noise (white noise and street noise showing greater positive shifts
than music sound), Mental Load (more positive shifts for mental load versus
no mental load), and DC Recording Location. Statistically significant higher
order interaction effects were also found. Low intensity of music sound
diminished the mental-load DC shift, interpreted as a possible compensatory
effect of soft music on mental load. The effect of mental load under street
noise and white noise conditions depends on the DC potential caused by
these background noises alone, showing a ceiling effect. Results indicate
that DC shifts apparent during mental load are changed by acoustic stimulation
additionally applied and that this effect is dependent on type of noise/sound
and stimulus intensity.
Trimmel's
list of electronically available abstracts/full text papers
Trimmel's English homepage
Trimmels (German) Homepage
E-mail: michael.trimmel@univie.ac.at