Listening effort: cardiovascular investigation through the point process framework

Listening effort is a mental effort experienced by humans during tasks involving listening. Traditional hearing screening or speech recognition thresholds do not provide any information about the stress experienced. Although there are qualitative and semi-quantitative measures to assess the amount of capacity allocated during acoustics tests, there is no agreement in the literature regarding physiological indices that allow to understand different listening effort levels. In the present study 21 normal young hearing subjects performed a validated speechin-noise test while they were monitored through the electrocardiographic and the blood volume pulse signals. The RR series from the electrocardiogram was modelled trough the point process framework from which cardiovascular indexes both in time and frequency domain were extracted in short time intervals. From the blood volume pulse alone and in conjuction with the RR series, the amplitude difference between each systole and diastole and the pulse arrival time were extracted. The average modelled RR series together with the pulse arrival time were found able to clearly distinguish the two different effort levels. Moreover, the amplitude difference between each systole and diastole was able to significantly separate high effort from both low effort and the initial resting period.