Terminology
Dementia in the elderly was once called senile dementia or senility, and viewed as a normal and somewhat inevitable aspect of aging.By 1913–20 the term dementia praecox was introduced to suggest the development of senile-type dementia at a younger age. Eventually the two terms fused, so that until 1952 physicians used the terms dementia praecox (precocious dementia) and schizophrenia interchangeably. Since then, science has determined that dementia and schizophrenia are two different disorders, though they share some similarities. The term precocious dementia for a mental illness suggested that a type of mental illness like schizophrenia (including paranoia and decreased cognitive capacity) could be expected to arrive normally in all persons with greater age (see paraphrenia). After about 1920, the beginning use of dementia for what is now understood as schizophrenia and senile dementia helped limit the words meaning to "permanent, irreversible mental deterioration". This began the change to the later use of the term. In recent studies, researchers have seen a connection between those diagnosed with schizophrenia and patients who are diagnosed with dementia, finding a positive correlation between the two diseases.The view that dementia must always be the result of a particular disease process led for a time to the proposed diagnosis of "senile dementia of the Alzheimers type" (SDAT) in persons over the age of 65, with "Alzheimers disease" diagnosed in persons younger than 65 who had the same pathology.
The relationship between general anesthesia and Alzheimers in elderly people is unclear.Little is known about the events that occur during and that actually cause Alzheimers disease. This is due to the fact that brain tissue from patients with the disease can only be studied after the persons death. However, it is known that one of the first aspects of the disease is a dysfunction in the gene that produces amyloid. Extracellular senile plaques (SPs), consisting of beta-amyloid (Aβ) peptides, and intracellular neurofibrillary tangles (NFTs) that are formed by hyperphosphorylated tau proteins, are two well-established pathological hallmarks of AD. Amyloid causes inflammation around the senile plaques of the brain, and too much build up of this inflammation leads to changes in the brain that cannot be controlled, leading to the symptoms of Alzheimers. Vascular
Vascular dementia accounts for at least 20% of dementia cases, making it the second most common type. It is caused by disease or injury affecting the blood supply to the brain, typically involving a series of mini-strokes. The symptoms of this dementia depend on where in the brain the strokes occurred and whether the blood vessels affected were large or small. Multiple injuries can cause progressive dementia over time, while a single injury located in an area critical for cognition such as the hippocampus, or thalamus, can lead to sudden cognitive decline. Elements of vascular dementia may be present in all other forms of dementia.Brain scans may show evidence of multiple strokes of different sizes in various locations.