On the feasibility of objective listening effort estimations by electroencephalographic correlates of corticofugal modulations

The availability of objective methods for the listening effort estimation could have a major impact on the fitting of modern hearing aids. However experimental and theoretical research dealing with this subject is still in its infancy. Recently, we have introduced a multiscale simulation scheme for auditory late responses (ALRs) and probabilistic auditory stream selection which focuses on corticothalamic feedback dynamics and corticofugal modulation. Using this scheme, the hypothesis can be derived that an increased listening effort results in a larger synchronization of the instantaneous phase of ALR single sweep sequences due to an increased corticofugal modulation. This hypothesis is verified experimentally in 20 subjects in the presented paper using two different auditory tasks which require a graduated effort for their solutions. It is concluded that the proposed neuropsychological and neurophysical modeling of stream selection provides an appropriate framework for listening effort estimation. The presented preliminary results of an ongoing study are encouraging, however, further focal research is necessary in order to estimate in how far the presented model and future extensions might support modern hearing aid fitting in practice.