can create free radicals which could influence the degeneration of the blood-brain barrier. One other specific age related factor noted in Popescu et al. is a decrease in estrogen as one ages could adversely affect the breakdown of the blood-brain barrier and create a sensitivity to neurodegeneration. As pointed out earlier, dementia is a broad category of memory impairments most commonly associated with ageing. Another symptom which should be monitored is Type 2 diabetes, which can lead to vascular dementia. Also linked with vascular dementia issues is high cholesterol; furthermore, this risk factor is related to cognitive decline, stroke, and Alzheimer's disease. It is estimated that within 20 years, worldwide prevalence will increase twofold. By 2050, this number is expected to increase to 115 million. Overall, dementia incidence is similar for men and women. However, after 90 years of age dementia incidence declines in men but not in women. Hyperthymestic syndrome Hyperthymestic syndrome causes an individual to have an extremely detailed autobiographical memory. Patients with this condition are able to recall events from every day of their lives (with the exception of memories before age five and days that were uneventful). This condition is very rare with only a few confirmed cases. Huntington's disease Huntington's disease (HD) is an inherited progressive disorder of the brain that leads to uncontrolled movements, emotional instability, and loss of intellectual faculties. Because of the inheritability of Huntington's each child born to a parent with Huntington's has a 50% chance of inheriting the disease, leading to a prevalence of almost 1 in 10,000 Canadians (0.01%). The first signs of Huntington's Disease are generally subtle; those affected commonly note tics and twitching as well as unexplained fluctuations of mood. Clumsiness, depression and irritability are noted. What begins as a slurring and slowing of speech eventually leads to difficulty communicating, reliance on a wheelchair, or confinement to a bed. Parkinson's disease Parkinson's disease (PD) is a neurodegenerative disease. PD and aging share a lot of the same neuropathologic and behavioral features. Movement is normally controlled by dopamine; a chemical that carries signals between the nerves in the brain. When cells that normally produce dopamine die off, the symptoms of Parkinson's appear. This degeneration also occurs in normal aging but is a much slower process. The most common symptoms include: tremors, slowness, stiffness, impaired balance, rigidity of the muscles, and fatigue. As the disease progresses, non-motor symptoms may