Noise as a participation criterion

More than 200 persons took part in the study between 2011 and 2013; the criterion for their selection was the Noise that reaches their bedrooms. Aviation noise had to be clearly audible, but with hardly any road or rail noise. Another criterion: the study participants had to have a regular sleeping rhythm and healthy sleeping patterns. People who worked shifts or suffered from disorders that influence sleeping patterns were not accepted as participants. This rigorous selection was important in order to rule out as far as possible causes for sleep disorders other than noise.