[Effects of various white noise levels on psychological cognition of school children].

In order to work out a hygienic standard for classroom-noise, 149 school children 8-9 yrs of age were put to psychological cognitive tests under the quiet [42 +/- 1dB(A)] and various white noise levels [50-65dB(A)] classroom conditions in 1986. The main results were as follows: Students under the three white noise levels [greater than or equal to 55dB(A)], all obtained significantly higher means of error scores along with the raising of the noise levels, also lower means of brain work-ability index than under the quiet classroom condition [42 +/- 1dB(A)]. The differences obtained between the three white noise levels [greater than or equal to 55dB(A)] groups and the control group were all statistically significant.