Characterizing olfaction, anxiety, and depression in subjective cognitive decline

Area of Science:

• Neuroscience
• Gerontology
• Psychiatry

Background:

• Olfactory dysfunction and neuropsychiatric symptoms are key in Alzheimer's disease (AD).
• Early detection of AD pathology in subjective cognitive decline (SCD) is crucial.
• The presence of olfactory dysfunction in SCD requires further investigation.

Purpose of the Study:

• To compare olfactory function and neuropsychiatric symptoms between individuals with SCD and healthy controls (HC).
• To determine if olfactory deficits are present in the prodromal stage of cognitive decline (SCD).

Main Methods:

• 110 older adults (59 SCD, 51 HC) participated.
• Olfactory function assessed using the Sniffin' Sticks battery.
• Anxiety and depression measured using validated questionnaires.

Main Results:

• SCD group had significantly lower global olfactory scores (d=0.41).
• SCD group reported higher depression (d=1.07) and anxiety (d=0.64) than HC.
• Olfactory performance combined with anxiety/depression improved group classification.

Conclusions:

• Subtle olfactory impairments are present in individuals with SCD.
• Olfactory and neuropsychiatric assessments may aid in early identification of cognitive decline.
• Further research using electrophysiological methods like olfactory-evoked potentials is warranted.