Olfactory acuity and cognitive function converge in older adulthood: support for the common cause hypothesis

Visual and auditory thresholds and cognitive variables have shown converging losses in old age, which might exist because standard cognitive tests rely on these modalities for assessment. The present study investigated the common cause hypothesis in another sensory modality. Structural equation modeling tested the fit of a model representing the common cause hypothesis for olfactory acuity and cognitive function data from 98 nondemented older adults and 103 younger adults. The model fit better the data from the older adults, consistent with the common cause hypothesis. In addition, unique influences of age beyond those shared between cognitive and sensory variables were also demonstrated. The results suggest that olfactory functioning may be a valid indicator of the integrity of the aging brain in older adults.