Phasic alerting increases visual processing speed in amnestic mild cognitive impairment

Abstract External warning cues temporarily increase the brain's sensitivity for upcoming events. Such increased levels of phasic alertness help individuals to flexibly adapt their reactions to the fast-changing requirements of highly complex visual environments. Previous studies reported that both younger and cognitively normal older adults profit from phasic alerting cues. Arguably, such an intact phasic alerting mechanism could be even more relevant in individuals with Alzheimer's disease who are characterized by pronounced reductions of general processing capacity. The present study employed a theory of visual attention based whole report paradigm with auditory cues in order to investigate phasic alerting effects in amnestic mild cognitive impairment (aMCI) on a purely perceptual level. In addition, patients with aMCI were compared to a previously reported sample of cognitively normal older adults. The analysis in patients indicated that their visual processing speed was significantly higher in the cue compared to the no-cue condition. Across groups, auditory alerting cues significantly increased visual processing speed. Further, visual processing speed was reduced in patients with aMCI compared to cognitively normal older adults, replicating prior findings. Taken together, the results suggest that the processing system of patients with aMCI exhibits general declines but can still integrate auditory warning signals on a perceptual level. Phasic alerting cues facilitate a temporary increase in processing speed, enabling an efficient handling of upcoming sensory information.