[Effects of noise on cortical mechanisms involved in the development of linguistic sounds].
So far studies about noise effects on speech perception have been focused on the development of hearing loss and other related pathologies. However, behavioral findings indicate that speech perception and intelligibility are disrupted in presence of noise in certain clinical groups in a way that is unpredictable on the basis of the audiogram performed in silence. This observation suggests that even soft noise can modify the cerebral mechanisms underlying speech information processing. Confirming the behavioral results, electric and magnetic brain measurements showed that noise presented to healthy subjects decreases the amplitude and increases the latency of brain responses to speech sounds. Recently, further experimental data allowed us to have a deeper knowledge of the neural mechanisms interventing in difficult listening conditions. In particolar, speech sounds presented in noisy background evoke bioelectric responses in neural populations located in the right cerebral hemisphere, that otherwise would not be activated. These findings can in future contribute to unveal new aspects of the noise pathology and its assessment in an early pre-clinical stage.
Brattico
E
E
Cognitive Brain Research Unit, University of Helsinki, Helsinki Brain Research Centre, Helsinki, Finland. elvira@cbru.helsinki.fi
Monitillo
V
V
Calabrese
S
S
Montrone
N
N
Nardulli
R
R
Multari
V
V
Ambrosi
L
L
D002540:Cerebral Cortex / Q000502:physiology*; D005071:Evoked Potentials; D007839:Functional Laterality; D006801:Humans; D008280:Magnetics; D009622:Noise; D013060:Speech / Q000502:physiology