Effects of attention and unilateral neglect on auditory stream segregation.

TLDR

Two experiments investigated how attention and unilateral neglect influence auditory streaming. The studies found that in healthy participants, auditory streaming is markedly diminished when attention is directed to a competing task in the contralateral ear, while in unilateral‑neglect patients, left‑ear tone sequences show reduced stream segregation compared to the right ear, indicating that attention modulates streaming and reveals lateralized perceptual differences in neglect.

Abstract

Two pairs of experiments studied the effects of attention and of unilateral neglect on auditory streaming. The first pair showed that the build up of auditory streaming in normal participants is greatly reduced or absent when they attend to a competing task in the contralateral ear. It was concluded that the effective build up of streaming depends on attention. The second pair showed that patients with an attentional deficit toward the left side of space (unilateral neglect) show less stream segregation of tone sequences presented to their left than to their right ears. Streaming in their right ears was similar to that for stimuli presented to either ear of healthy and of brain-damaged controls, who showed no across-ear asymmetry. This result is consistent with an effect of attention on streaming, constrains the neural sites involved, and reveals a qualitative difference between the perception of left- and right-sided sounds by neglect patients.