Acoustic and Neurophysiological Aspects of Lombard Effect

PurposeThis study aims to describe variations in acoustic and electroencephalography measures when speaking in the presence of background noise (Lombard effect) in participants with typical voice and normal hearing. MethodTwenty-one participants with typical voices and normal hearing uttered simple vocal tasks in three sequential background conditions: Baseline (in quiet), Lombard (in noise), and Recovery (five minutes after removing the noise). Acoustic and electroencephalography signals were recorded in all conditions. The noise used in the Lombard condition consisted of speech-shaped noise at 80 dB SPL sent by headphones. Acoustic measure, and ERP responses were analyzed. ResultsDuring the Lombard condition, the participants increased the intensity of their voice, accompanied by an increase in CPP, and a decrease in H1-H2. The cortical response was characterized by the increased N1-P2 complex amplitude of the ERP elicited by the subjects own vocalizations in noise, The source localization showed neural activities in frontal and temporal cortical regions. ConclusionsThe variation in acoustic measures due to the Lombard Effect could be modulated by temporal, and cortical regions.