Fatigue and adaptation in noisy primary schools

A large data set collected in 6 primary schools, which regarded 741 pupils 6 to 10 years old (I to V grade), was used to investigate the changes of the listening eciency indicator during the duration of the tests. This challenging task was undertaken by dividing the 45 minutes test session into 9 slots of 5 minutes each. By doing so, it was possible to detail the behavior of the pupils during the test. Then, in some cases, trends of the listening eciency were isolated. A decrease of the quantity during the test generally happens under better acoustical conditions and was related to a fatigue eect on the testers. Surprisingly also the reverse eect, that is an increase of the listening eciency, was observed, and this behavior was predominant under worse acoustical conditions. In this case the mechanism of adaptation was thought to be predominant. The above trends were subjected to statistical analysis with permutation tests to validate their relevance according to a given statistical p-value. Then, other intelligibility tests were accomplished under no noise - no reverberation conditions (NNR) with both adults (41) and 6 to 10 years old pupils (205). The signal level was presented within a range of 12 dB(A) in order to investigate and extract the conditions with the highest listening eciency for each group. The values of speech intelligibility, response time and hence listening eciency were set as references for the acoustical comfort (disregarding the other environmental issues).