With the aging population, and an estimated 2.3 million people living with multiple sclerosis (MS) and 46 million with Alzheimer disease (AD) or other dementias worldwide, it will become increasingly important to recognize and understand how to manage individuals with these complex comorbid conditions. There is strikingly little information, however, on the coexistence of MS with many common diseases of aging. In particular, little appears to be known about the coexistence of MS with AD, the most common form of dementia. In a recent review, researchers explore what is known about the coexistence of these 2 conditions, including a focused literature search to identify any reports of individuals with both MS and AD. They also discuss the wider epidemiology, diagnosis, and pathophysiology of MS and AD. Key highlights include:

• 24 individuals were found with pathological features of both MS and AD described as case series or reports (published between 1976–2014), but no epidemiological or population-based studies, aside from 1 conference proceeding (2011).
• Comorbid MS and AD was reported in a broad range of MS disease courses including relapsing-remitting, primary progressive, secondary progressive, and so-called “benign.”