The influence of different types of auditory change on processes associated with the switching of attention in older adults and people with mild cognitive impairment.

The involuntary detection of acoustic change following presentation of rarely presented deviant auditory stimulus will elicit an event-related potential (ERP), the deviant-related negativity (DRN). If the deviant stimulus is potentially highly relevant, a later P3a may also be elicited. This is thought to reflect processes associated with the switching of attention away from current processing demands. Previous studies have indicated that cognitively healthy older adults are less able to switch processing priorities upon presentation of these stimuli compared to young adults. The present study examined if people with mild cognitive impairment (MCI) are less able to switch processing priorities than cognitively healthy older adults. Two experiments were run. In each, 20 healthy older adults and 20 people with MCI were presented with to-be-ignored auditory stimuli while engaged in a visual task. The auditory stimuli consisted of frequently-presented standards and different types of deviants. In Experiment 1, the deviants represented either decreases or increases in the intensity of the standard. In Experiment 2, six different deviants were presented. In both experiments, a DRN was elicited by all deviants. Its amplitude did not, however, significantly differ between the two groups. Only the increment, white noise, and environmental sound deviants elicited a P3a. This P3a also did not significantly differ between the two groups. These results indicate that there is no evidence that the ability to switch processing priorities differs between people with MCI and cognitively healthy older adults.