The discovery has several implications. From a practical viewpoint, "I think it has quite a bit to offer," says Christoph E. Schreiner, UCSF professor of otolaryngology and a co-author of the study. In particular, it might present a technique for retraining people with partial hearing loss, who often cannot hear very soft sounds but have normal hearing at higher volume levels.
"There's a very steep volume curve that goes from soft to very loud right away, and people have a hard time with that," Schreiner explains, "especially for hearing-aid users." However, they -- or their auditory cortexes -- might be trained to be more sensitive to minor volume changes at the lower threshold of hearing, "so this steep transition doesn't bother them anymore." Similarly, such training might be of value to profoundly hearing-impaired people with cochlear implants, which replace the function of the inner ear but are not as sensitive to small volume changes.
Another group that might be helped is children with sensory-modulation disorders, including children with autism. These children are "overwhelmingly sensitive" to changes in their environment, explains Polley. "So when presented with a moderate stimulus -- a sound, a touch, a flash of light -- they respond as if their entire sensory systems have become overwhelmed. What might be needed in their brains is greater selectivity." Potentially, they could be trained to distinguish smaller degrees of change in their environments. Being perceived as gradual, these changes would be less overwhelming.
From a psychological viewpoint, the study says something about how we acquire and refine new skills. When we speak of training a musician's ear or a painter' s eye, speculates Polley, we may be referring to the alternate sensory processing system employed
Contact: Jennifer O'Brien
University of California - San Francisco