Listening difficulties in children: bottom-up and top-down contributions.

The brain mechanisms of hearing include large regions of the anterior temporal, prefrontal, and inferior parietal cortex, and an extensive network of descending connections between the cortex and sub-cortical components of what is presently known as the auditory system. One important function of these additional ('top-down') mechanisms for hearing is to modulate the ascending, sensory ('bottom-up') auditory information from the ear. In children, normal, immature hearing during the first decade of life is more strongly influenced by top-down mechanisms than in adulthood. In some children, impaired top-down function presents a significant challenge to their auditory perception, often associated with a range of language and learning difficulties and sometimes called auditory processing disorder.