Cerebral Small Vessel Disease in Older Adults With Olfactory Dysfunction

Area of Science:

• Neuroscience
• Gerontology
• Vascular Health

Background:

• Poor vascular health is linked to age-related sensory declines, including olfaction.
• Cerebral small vessel disease (CSVD) is hypothesized to underlie olfactory dysfunction via structural brain changes.

Purpose of the Study:

• To test if CSVD causes olfactory decline by affecting brain regions supporting olfaction.
• To compare olfactory and hearing difficulties in relation to CSVD and brain structure.

Main Methods:

• 166 older adults underwent olfactory testing (Sniffin' Sticks) and brain imaging for white matter hyperintensity (WMH) volume.
• Cortical thickness and disconnection analyses were performed in relation to olfaction and hearing difficulty (RHHI).

Main Results:

• Higher WMH volume correlated with poorer olfaction and hearing difficulty.
• Poorer olfaction, unlike hearing difficulty, was linked to disconnected cortex with reduced thickness in olfactory and cognitive-related regions.
• These olfactory changes were associated with lower episodic memory and processing speed.

Conclusions:

• CSVD increases risk for olfactory and hearing difficulties.
• Olfactory decline associated with CSVD involves tissue loss, potentially explaining age-related smell dysfunction and cognitive impairment.