The NINCDS-ADRDA Alzheimer's Criteria were proposed in 1984 by the National Institute of Neurological and Communicative Disorders and Stroke and the Alzheimer's Disease and Related Disorders Association (now known as the Alzheimer's Association) and are among the most used in the diagnosis of Alzheimer's disease

Alzheimer's disease

Alzheimer's disease also known in medical literature as Alzheimer disease is the most common form of dementia. There is no cure for the disease, which worsens as it progresses, and eventually leads to death...

 (AD). These criteria require that the presence of cognitive impairment and a suspected dementia

Dementia

Dementia is a serious loss of cognitive ability in a previously unimpaired person, beyond what might be expected from normal aging...

 syndrome

Syndrome

In medicine and psychology, a syndrome is the association of several clinically recognizable features, signs , symptoms , phenomena or characteristics that often occur together, so that the presence of one or more features alerts the physician to the possible presence of the others...

 be confirmed by neuropsychological testing

Neuropsychological assessment

Neuropsychological assessment was traditionally carried out to assess the extent of impairment to a particular skill and to attempt to locate an area of the brain which may have been damaged after brain injury or neurological illness...

 for a clinical diagnosis of possible or probable AD; while they need histopathologic confirmation (microscopic

Microscopic

The microscopic scale is the scale of size or length used to describe objects smaller than those that can easily be seen by the naked eye and which require a lens or microscope to see them clearly.-History:...

 examination of brain tissue) for the definitive diagnosis. They specify as well eight cognitive domains that may be impaired in AD. These criteria have shown good reliability

Reliability (statistics)

In statistics, reliability is the consistency of a set of measurements or of a measuring instrument, often used to describe a test. Reliability is inversely related to random error.-Types:There are several general classes of reliability estimates:...

 and validity

Validity (statistics)

In science and statistics, validity has no single agreed definition but generally refers to the extent to which a concept, conclusion or measurement is well-founded and corresponds accurately to the real world. The word "valid" is derived from the Latin validus, meaning strong...

.

Criteria

• Definite Alzheimer's disease: The patient meets the criteria for probable Alzheimer's disease and has histopathologic evidence of AD via autopsy
  Autopsy
  An autopsy—also known as a post-mortem examination, necropsy , autopsia cadaverum, or obduction—is a highly specialized surgical procedure that consists of a thorough examination of a corpse to determine the cause and manner of death and to evaluate any disease or injury that may be present...
  
   or biopsy
  Biopsy
  A biopsy is a medical test involving sampling of cells or tissues for examination. It is the medical removal of tissue from a living subject to determine the presence or extent of a disease. The tissue is generally examined under a microscope by a pathologist, and can also be analyzed chemically...
  
  .
• Probable Alzheimer's disease: Dementia has been established by clinical and neuropsychological examination. Cognitive impairments also have to be progressive and be present in two or more areas of cognition. The onset of the deficits has been between the ages of 40 and 90 years and finally there must be an absence of other diseases capable of producing a dementia syndrome.
• Possible Alzheimer's disease: There is a dementia syndrome with an atypical onset, presentation or progression; and without a known etiology; but no co-morbid diseases capable of producing dementia are believed to be in the origin of it.
• Unlikely Alzheimer's disease: The patient presents a dementia syndrome with a sudden onset, focal neurologic signs
  Focal neurologic signs
  Focal neurologic signs also known as focal neurological deficits or focal CNS signs are impairments of nerve, spinal cord, or brain function that affects a specific region of the body, e.g...
  
  , or seizures or gait
  Gait
  Gait is the pattern of movement of the limbs of animals, including humans, during locomotion over a solid substrate. Most animals use a variety of gaits, selecting gait based on speed, terrain, the need to maneuver, and energetic efficiency...
  
   disturbance early in the course of the illness.

Cognitive domains

The NINCDS-ADRDA Alzheimer's Criteria specify eight cognitive domains that may be impaired in AD: memory

Memory

In psychology, memory is an organism's ability to store, retain, and recall information and experiences. Traditional studies of memory began in the fields of philosophy, including techniques of artificially enhancing memory....

, language

Language

Language may refer either to the specifically human capacity for acquiring and using complex systems of communication, or to a specific instance of such a system of complex communication...

, perceptual skills

Perception

Perception is the process of attaining awareness or understanding of the environment by organizing and interpreting sensory information. All perception involves signals in the nervous system, which in turn result from physical stimulation of the sense organs...

, attention

Attention

Attention is the cognitive process of paying attention to one aspect of the environment while ignoring others. Attention is one of the most intensely studied topics within psychology and cognitive neuroscience....

, constructive abilities, orientation

Orientation (mental)

Orientation is a function of the mind involving awareness of three dimensions: time, place and person. Problems with orientation lead to disorientation, and can be due to various conditions, from delirium to intoxication...

, problem solving

Problem solving

Problem solving is a mental process and is part of the larger problem process that includes problem finding and problem shaping. Consideredthe most complex of all intellectual functions, problem solving has been defined as higher-order cognitive process that requires the modulation and control of...

 and functional abilities).

Other criteria

Similar to the NINCDS-ADRDA Alzheimer's Criteria are the DSM-IV-TR criteria published by the American Psychiatric Association

American Psychiatric Association

The American Psychiatric Association is the main professional organization of psychiatrists and trainee psychiatrists in the United States, and the most influential worldwide. Its some 38,000 members are mainly American but some are international...

. At the same time the advances in functional neuroimaging

Neuroimaging

Neuroimaging includes the use of various techniques to either directly or indirectly image the structure, function/pharmacology of the brain...

 techniques such as PET

Positron emission tomography

Positron emission tomography is nuclear medicine imaging technique that produces a three-dimensional image or picture of functional processes in the body. The system detects pairs of gamma rays emitted indirectly by a positron-emitting radionuclide , which is introduced into the body on a...

 or SPECT that have already proven their utility to differentiate Alzheimer's disease from other possible causes, have led to proposals of revision of the NINCDS-ADRDA criteria that take into account these techniques.