Effects of diurnal changes on temporal processing in morning-type and evening-type individuals with normal hearing

The present study aims at determining the influence of diurnal changes in duration discrimination and temporal resolution in the morning- and evening-type individuals with normal hearing sensitivity.

Sixty individuals with normal hearing were divided into morning, evening and intermediate types using the Morningness-Eveningness Questionnaire. Tests for Duration discrimination, Gap detection, and Temporal modulation transfer function were carried out in all the participants during morning and evening. The performance of subjects of all the three groups during both morning and evening was analyzed.

Results revealed a diurnal effect on morning and evening type individuals' performance where morning type exhibited better performance when tested during morning and evening individuals when tested during the evening. At the same time, there were no significant diurnal effects seen in the intermediate type.

The poor cognitive performance and lack of inhibitory control at the time of the off-peak hours possibly result in the poor scores. Furthermore, the diurnal effects on objective audiological tests in morning and evening type individuals should be studied. The influence of diurnal changes could be considered an extraneous variable in future research on psychoacoustic tests in younger adults.