walking. Cerebrovascular disease Cerebrovascular disease refers to the process by which blood vessels in the brain are damaged and/or brain tissue is injured from not receiving enough blood, oxygen or nutrients. People with dementia whose brains show evidence of cerebrovascular disease are said to have vascular dementia. Vascular dementia occurs most commonly from blood vessel blockage, such as that which occurs with stroke, or damage leading to areas of dead tissue or bleeding in the brain. The location, number and size of the brain injuries determine whether dementia will result and how the individual’s thinking and physical functioning will be affected. Some cerebrovascular disease is commonly present in people with Alzheimer’s, and may worsen symptoms. About 5% to 10% of individuals with dementia show evidence of vascular dementia alone.21-22 However, it is more common as a mixed pathology, with most people living with dementia showing the brain changes of cerebrovascular disease and Alzheimer's disease.21-22 Symptoms Slowed thoughts or impaired ability to make decisions, plan or organize may be the initial symptoms, but memory may also be affected, especially when the brain changes of other causes of dementia are present. In addition to changes in cognitive function, people with vascular dementia commonly become less emotional and have difficulty with motor function, especially slow gait and poor balance. Lewy body disease Lewy bodies are abnormal aggregations (or clumps) of the protein alpha-synuclein in neurons. When they develop in a part of the brain called the cortex, dementia can result. This is called dementia with Lewy bodies or DLB. About 5% of older individuals with dementia show evidence of DLB alone, but most people with DLB also have Alzheimer's disease pathology. Symptoms People with DLB have some of the symptoms common in Alzheimer’s, but are more likely to have initial or early symptoms of sleep disturbances, well-formed visual hallucinations and visuospatial impairment. These symptoms may differ dramatically hourly or from day to day. Problems with motor function (similar to Parkinson’s disease) are also common. They may occur in the absence of significant memory impairment, but memory loss often occurs at some point in the disease, especially when the brain changes of other causes of dementia are present. Overview 7 Common Causes of Dementia and Associated Characteristics* Cause Characteristics table 1 (cont.) Frontotemporal lobar degeneration (FTLD) FTLD includes dementias such as behavioral-variant FTLD, primary progressive aphasia, Pick’s disease, corticobasal degeneration and progressive supranuclear palsy. Nerve cells in the front (frontal lobe) and side regions (temporal lobes) of the brain are especially affected, and these regions become markedly atrophied (shrunken). In addition, the upper layers of the cortex typically become soft and spongy and abnormal protein is present (usually tau protein or the transactive response DNA-binding protein, TDP-43). The symptoms of FTLD may occur in those age 65 years and older, similar to Alzheimer’s, but most people with FTLD develop symptoms at a younger age. About 60% of people with FTLD are ages 45 to 60.23 Some scientists think that FTLD is the most common cause of dementia in people younger than 60.23 In a systematic review, FTLD accounted for about 3% of dementia cases in studies that included people 65 and older and about 10% of dementia cases in studies restricted to those younger than 65.24 Symptoms Typical early symptoms include marked changes in personality and behavior and/or difficulty with producing or comprehending language. Unlike Alzheimer’s, memory is typically spared in the early stages of disease. Parkinson’s disease (PD) In PD, clumps of the protein alpha-synuclein appear in an area deep in the brain called the substantia nigra. These clumps are thought to cause degeneration of the nerve cells that produce dopamine.25 As PD progresses, alpha-synuclein can also accumulate in the cortex of the brain. Dementia may result. Symptoms Problems with movement (slowness, rigidity, tremor and changes in gait) are common symptoms of PD. Cognitive symptoms develop later in the disease, years after movement symptoms. Hippocampal sclerosis (HS) HS is the shrinkage and hardening of tissue in the hippocampus of the brain. The hippocampus plays a key role in forming memories. HS brain changes are often accompanied by accumulation of the misfolded protein TDP-43. HS is a common cause of dementia in the "oldest-old," individuals age 85 or older. Symptoms The most pronounced symptom of HS is memory loss, and individuals are often misdiagnosed as having Alzheimer's disease. Mixed pathologies When an individual shows the brain changes of more than one cause of dementia, “mixed pathologies” are considered the cause. When these pathologies result in dementia symptoms during life, the person is said to have mixed dementia or mixed etiology dementia. Studies suggest that mixed dementia is more common than previously recognized, with more than 50% of people diagnosed with Alzheimer’s dementia who were studied at Alzheimer's Disease Research Centers having pathologic evidence of more than one cause of dementia.22 In community-