Evidence of significant vascular disease can be found in as many as one-third of cases of dementia. A history of hypertension, stroke or clear-cut transient ischemic attacks and the presence of localizing signs on neurologic exam makes a vascular contribution to the dementia very likely. These include a wide variety of Parkinson-like motor presentations accompanied by fluctuating cognitive abilities and, frequently, hallucinations. Normal pressure hydrocephalus is often raised as a possibility on radiologic studies. It should only be seriously considered when the dementia is mild and follows a more severe gait disturbance.
Incontinence is variable.
This involves physical and neurological examination accompanied by cognitive testing to identify the characteristic memory, language and other cognitive and non-cognitive symptoms. The neurologic exam should focus on identifying localizing signs and Parkinsonism. Head CT or MRI are useful to exclude structural lesionswhich may contribute to the dementia such as cerebral infarctions, neoplasm, extracerebral fluid collections and hydrocephalus. No currently available ante-mortem tests can provide definitive diagnosis despite the commercial availability of genetic and spinal fluid markers and neuroimaging. The average survival for patients diagnosed with probable Alzheimer's disease is about eight years, though the range is quite wide and may extend in excess of 15 years.