Degraded voices through mobile phones and their neural effects: A possible risk of using mobile phones during driving

We firstly studied qualities of voices transmitted from a mobile phone in a building to another in the same building or in a car. The voices were found to be often degraded and the degradations were classified in one of the three types: delay of transmission, spectral distraction (distractions in the spectral structure of the voices) and silent interruptions. The interruptions occurred more frequently and longer if the car with the phone for receiving was moving than at rest. Secondly, brain responses to the interruptions were measured with magnetoencephalography (MEG). It was found that the cortex was bilaterally activated both at starts and ends of the interruptions. Our another study [Hamada, T., Iwaki, S., & Kawano, T. (2004). Speech offsets activate the right parietal cortex. Hearing Research, 195, 75-78] had shown that these activities are reduced to sources in the brain for auditory perception and auditory attention. This suggests that listening to voices through a mobile phone during driving would allocate less resources for auditory perception and attention at moments of the interruptions.