Indices of Effortful Listening Can Be Mined from Existing Electroencephalographic Data.

OBJECTIVES: Studies suggest that theta (~4 to 7 Hz), alpha (~8 to 12 Hz), and stimulus-evoked dynamics of the electroencephalogram index effortful listening. Numerous auditory event-related potential datasets exist, without thorough examination of these features. The feasibility of mining those datasets for such features is assessed here.

DESIGN: In a standard auditory-oddball paradigm, 12 listeners heard deviant high-frequency tones (10%) interspersed among low-frequency tones (90%) "near" or "far" separated in frequency.

RESULTS: During active listening (deviance detection; experiment 1), sustained frontal midline theta power, and gamma-band inter-trial phase coherence, were greater for the near condition. No significant "near"/"far" differences were observable during passive exposure to the same sounds (experiment 2).

CONCLUSIONS: Increased theta power likely reflects increased utilization of cognitive-control processes (e.g., working memory) that rely on frontal cortical networks. Inter-trial phase coherence differences may reflect differences in attention-modulated stimulus encoding. Reanalysis of existing datasets can usefully inform future work on listening effort.