Hormone and Information Processing Study

Natural age related declines in testosterone (T) are associated with decreases in cognitive abilities independent of health status. Low T levels over time are associated with increased risk for developing Alzheimer's disease (AD). These findings suggest that men with low T levels are most at risk for age-related cognitive decline and AD and therefore most likely to benefit from T supplementation to prevent the development of AD or age-associated cognitive decline. The current study will assess cognition, mood, and cerebral spinal fluid (CSF) biomarker response to T supplementation in older men with mild cognitive impairment (MCI) and low T levels. Participants will be randomized to either receive T treatment or a placebo for six months. Participants will come in for about five visits within the span of six months where they will complete cognitive \& memory tests, fill out mood questionnaires, and have their blood drawn to monitor the medication level. A sample of blood will also be taken at one visit to test for apolipoprotein E (APOE), which is a genetic risk factor associated with AD. Participants will have the option to get a spinal tap in order to measure biological markers associated with Alzheimer's disease including beta-amyloid 1-40, 42, total-tau, and phosphorylated-tau-181-231. This will require an additional two visits.