Odor is more effective than a visual cue or a verbal cue for the recovery of autobiographical memories in AD

Alzheimer's disease (AD) is associated with an impairment of autobiographical memories, leading to the production of nonspecific memories. Recent research has demonstrated that odor can serve as a powerful cue for the retrieval of autobiographical memories in AD. Moreover, studies conducted in young adults have showed that odor-evoked autobiographical memories are evoked with more details compared with memories triggered by other sensory modalities. Building on the latter research, we compared specificity, subjective experience, emotional characteristics and retrieval time of autobiographical memories evoked by odor cue, visual cue and verbal cue. To this end, we invited participants with mild AD and control participants to retrieve autobiographical memories after the presentation of an odor, a visual representation of the odorant, or a verbal label of the odorant. Results showed more specificity, higher arousal and more positive memories after odor exposure compared to the visual cue and verbal cue in AD and control participants. In AD participants, autobiographical were retrieved faster after odor-exposure compared to memories evoked by a visual cue and a verbal cue, suggesting the automatic nature of odor-evoked autobiographical memories. Overall, these findings demonstrate that odor is more effective than visual or verbal cues for autobiographical retrieval in AD.