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Are visual attentional functions already impaired at a prodromal stage of Alzheimer´s disease (AD), referred to as mild cognitive impairment (MCI)? The present work revealed an elevation of the perceptual threshold already in MCI, while perceptual processing speed and visual short-term memory storage capacity showed a significant decline for AD patients, only. These results indicate a staged pattern of deficits affecting pre-attentive processing in MCI and attentive processing, fitting into the prominent amyloid cascade hypothesis of AD. Parameters of spatial and task-related selection might also function as early cognitive markers since both aspects are already impaired in MCI. In carriers of the ApoE4 allele (higher risk of AD), a spatial lateralization towards the left visual hemifield was revealed. The bias was the more pronounced the earlier disease onset. These results indicate that impaired task-related selection may be linked to early dysfunction of fronto-parietal attentional networks. Accompanying, PET imaging results suggest that an early interhemispheric asymmetry in temporo-parietal cortical interactions might cause this pathological spatial bias.

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Dr. Petra Redel started her scientific career as PhD student atthe chair of General and Experimental Psychology/ Neuro-CognitivePsychology (NCP) at the Ludwig Maximilian University in Munich.There, she works as postdoc on attentional functions in normalageing and neurodegenerative diseases. She also coordinates theelite NCP master program.

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