Brain amyloid-β (Aβ) deposition is widely believed to be an early event in Alzheimer's disease (AD). Aβ plaques, along with intracellular neurofibrillary tangles, which largely comprise hyperphosphorylated tau (HPτ), are considered to be neuropathological hallmarks of AD. Brain biopsies from living subjects could be used to evaluate these findings. It is possible to obtain biopsies from patients with presumed normal pressure hydrocephalus during diagnostic or shunt procedures. The presence of

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... th Aβ and HPτ in frontal cortex biopsy samples seems to be a strong indicator of AD with high specificity (98 %) but rather low sensitivity (36 %). Aβ alone is associated with AD and exhibits high sensitivity (87 %) but lower specificity (69 %), indicating that many patients with Aβ only may also develop clinical dementia other than AD. Although a definite diagnosis of AD can only be confirmed at autopsy, brain biopsies may be useful for identification of novel markers of AD in a research context. In addition, when available, brain biopsy can be a useful diagnostic aid and validate non-invasive techniques in the diagnosis of dementia.