It’s rare, but a disease linked with old age sometimes strikes during the prime of life. Find out what's known about signs of dementia in your 40s or 50s.

Historically, dementia has been used as a catch-all phrase for symptoms of degenerative disorders of the brain. Several of these disorders are associated with vivid dreams and sleep disturbances as well as the more common symptoms of confusion, daytime hallucinations and progressive loss of mental functioning.

Lewy body dementia, or LBD, is a common cause of dementia. According to the Lewy Body Dementia Association, 1.3 million Americans have LBD. Like Alzheimer disease, LBD causes intellectual and physical deterioration due to progressive damage of brain cells.

Melatonin is promoted as a fast and natural sleep aid, with fewer side effects than traditional prescription sleep medications. Its natural quality is part of what makes it so appealing; however, it may not be appropriate for everyone.

A person may live a long life with a lucid mind and good memory. However, many senior citizens have dementia, or severe intellectual deterioration involving progressive memory loss and inability to concentrate. Rarely, dementia affects people in their 50s. Various factors may cause such early dementia.

Vascular dementia, according to the Mayo Clinic, is the term for cognitive impairments that result from a problem with the brain’s blood supply. There are many different types of vascular dementia, and as many as one to four percent of those over the age of 65 will experience some form of the condition.