Changes in Wakefulness during Exposure to Noise at 42 Hz, 1000 Hz and Individual EEG Frequencies

This report includes two investigations. Investigation 1 was carried out in order to study the correlation between changes in wakefulness and exposure to low frequency and high frequency noise. The investigation included 20 subjects. Changes in wakefulness were analysed through EEG- and EKG-recordings. The results of the experiment indicate a reduction in wakefulness during exposure to a repeating 42Hz, 70dB signal and an increase in wakefulness during a repeating 1000Hz, 30dB signal. Investigation 2 was made in order to analyse the correlation between the tiring effect of low frequency noise and the individual EEG signals. Special interest was thus directed towards the question whether drowsiness is influenced by a synergetic effect between sound and EEG frequencies. The design of the experiment was made in order to obtain a noise exposure continuously regulated by the EEG of the subject. Changes in wakefulness were analysed through spectral analysis of the EEG and ECG. The results of the investigation did not show any significant proofs for the theory that drowsiness is influenced by a synergetic correlation between sound waves and sound coordinated EEG. Further conclusions should be based on larger experiments.