Increased morning salivary cortisol levels in older adults with nonamnestic and multidomain mild cognitive impairment

Exposure to elevated glucocorticoid levels has a detrimental impact on cognitive function. In the present study, elderly individuals were classified according to their cognitive status to (i) cognitively healthy; (ii) amnestic; (iii) nonamnestic; or (iv) multidomain, with an extensive cognitive profiling. Salivary cortisol samples were taken at awakening, evening and night. We report that, compared to cognitively normal control individuals, subjects with nonamnestic or multidomain mild cognitive impairment profiles show increased salivary cortisol levels, immediately after awakening, but not in the evening or at night. Importantly, individuals with amnestic mild cognitive impairment did not show this increase in salivary cortisol levels. We also found that higher morning cortisol levels were associated with a lower global cognitive state, as well as poorer score in executive function and visuoconstructive praxes, verbal fluency, and a worse free immediate recall of items from a word list. These findings open new avenues to the use of salivary cortisol levels as a possible biomarker for nonamnestic and multidomain mild cognitive impairment in elderly subjects.