COGNITIVE IMPAIRMENT IN OLDER ADULTS WITH MCI DUE TO SNAP MAY BE PARTIALLY ATTRIBUTABLE TO COMORBID CONDITIONS AND USE OF ANTICHOLINERGIC MEDICATION

Abstract

A number of individuals presenting with mild cognitive impairment (MCI) show a biomarker negative pattern (no amyloid, tau, or neurodegeneration), which has been termed suspected non-Alzheimer's pathology (SNAP; Jack et al. (2016) Nature Review Neurology). To better understand this group, we analyzed this the presence of comorbidities and medication use in A/T/N negative late MCI (LMCI) individuals from ADNI. MCI participants were divided based on their positivity on CSF measures of amyloid-beta (A) and tau (T), as previously described (Shaw et al. 2008), as well as hippocampal atrophy (HA, our measure of neurodegeneration (N)). A hippocampal volume that was −1.5 standard deviations below the average value for cognitively normal controls, adjusted for age, sex, and ICV was considered as positive for HA. Medical history of cardiovascular disease (CVD) and depression/anxiety were considered, as well as use of anticholinergic medications (AC; high/medium effect, low effect). Chi-square tests were used to compare individuals who were amyloid positive (with or without tau/atrophy positivity; n=261) to SNAP individuals with LMCI (n=56). SNAP LMCI participants showed an increased percentage of CVD (94.6%) than amyloid-positive LMCI participants (84.7%; p=0.041). In addition, SNAP LMCI participants were more likely to be taking medium/high activity AC medications (26.8%) relative to amyloid-positive LMCI (12.3%; p=0.017). Cognitive impairment in older adults with SNAP MCI patients may be partially attributable to comorbid medical conditions and anticholinergic medication use.