Imagine trying to listen to a friend speak over the commotion of a loud party. It is difficult to detect and process sounds in noisy environments, especially for those with hearing loss. Previous research has typically focused on how competing sounds influence cortical brain activity, with the end goal of informing treatment strategies for people who are hard of hearing. But in a new eNeuro study, Melissa Polonenko and Ross Maddox, from the University of Rochester, explored a lesser-studied influence of competing sounds on subcortical brain activity. Because the subcortex processes sounds before the cortex does, shedding light on how sounds are processed in the subcortex has the potential to improve treatment strategies for and clinical assessments of those with hearing loss.
In their investigation, the researchers measured subcortical brain activity as participants processed simultaneous speech streams ranging from one to five talkers. Subcortical responses to speech concealed by simultaneous speech streams were increasingly smaller and delayed as more speech streams came into play. According to the authors, an important next step may be to determine whether people who struggle to hear in noisy environments undergo more significant subcortical changes than those who have an easier time hearing.
"This has implications for hearing loss, but also for those who do not have hearing loss and have extra challenges hearing when multiple people are talking at the same time," says Polonenko.
