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Kansagara D, Freeman M. A Systematic Evidence Review of the Signs and Symptoms of Dementia and Brief Cognitive Tests Available in VA [Internet]. Washington (DC): Department of Veterans Affairs (US); 2010 Apr.



Failure to recognize or identify objects despite intact sensory function.

Alzheimer’s disease (AD)

A disease usually characterized by loss of memory, especially for learning new information, reflecting deterioration in the functioning of the medial temporal lobe and hippocampus areas of the brain. Later in the illness, other higher functions of the cerebral cortex become affected: these include language, praxis (putting theoretical knowledge into practice) and executive function (involved in processes such as planning, abstract thinking, rule acquisition, initiating appropriate actions and inhibiting inappropriate actions, and selecting relevant sensory information). Behavioral and psychiatric disturbances are also seen, which include depression, apathy, agitation, disinhibition, psychosis (delusions and hallucinations), wandering, aggression, incontinence and altered eating habits.


Deterioration in language skills, such as word-finding difficulties, reduction in output, loss of fluency, and poor comprehension.


Total or partial loss of the ability to perform coordinated movements or manipulate objects in the absence of motor or sensory impairment.


The strategy of identifying a new occurrence of disease among patients selected on the presence of risk factors, signs, or symptoms.


A group of persons with a common characteristic or set of characteristics. Typically, the group is followed for a specified period of time to determine the incidence of a disorder or complication of an established disorder (prognosis).

Cohort Study

(Cohort Analytic Study): Prospective investigation of the factors that might cause a disorder in which a cohort of individuals who do not have evidence of an outcome of interest but who are exposed to the putative cause are compared with a concurrent cohort who are also free of the outcome but not exposed to the putative cause. Both cohorts are then followed to compare the incidence of the outcome of interest. Used for Prospective Study.


The development of multiple cognitive deficits that include memory impairment and at least 1 of the following cognitive disturbances: agnosia, aphasia, apraxia, or a disturbance in executive functioning. Deficits must be severe enough to cause significant decline in social or occupational functioning and must represent a decline from previous baseline functioning.

Dementia with Lewy bodies (DLB)

One of the most common types of progressive dementia and shares characteristics with both Alzheimer’s and Parkinson’s diseases. Its central feature is progressive cognitive decline, combined with three additional defining features: pronounced fluctuations in alertness and attention, such as frequent drowsiness, lethargy, lengthy periods of time spent staring into space or disorganised speech; recurrent visual hallucinations; and parkinsonian motor symptoms, such as rigidity and the loss of spontaneous movement. The symptoms of DLB are caused by the build-up of Lewy bodies (protein deposits found in nerve cells) in areas of the brain that control particular aspects of memory and motor control.

Executive Functioning

The ability to think abstractly and to plan, initiate, sequence, monitor, and stop complex behavior.


The ability to recognize a number or letter written on the skin by the sensation of touch.


A term used to illustrate the variability or differences between studies in the estimates of effects.


The number of new cases of a disease per population over a given time period. Incidence measures how frequently a new case of disease occurs, as opposed to prevalence, which conveys how widespread a disease is in a population.

Inter-rater reliability

A measure of the extent to which multiple raters or judges agree when providing a rating, scoring, or assessment.

Key questions

Questions posed by the advisory panel that are used to guide the identification and interrogation of the evidence base relevant to the topic of the guideline.

Likelihood Ratio

For a screening or diagnostic test (including clinical signs or symptoms), expresses the relative likelihood that a given test result would be expected in a participant with (as opposed to one without) a disorder of interest.

Mild Cognitive Impairment (MCI)

Presence of a memory complaint, preferably corroborated by an informant, objective memory impairment, and normal general cognitive function. Activities of daily living are intact and the patient does not meet clinical criteria for dementia.

Neuropsychiatric symptoms

Symptoms which generally fall within one of three symptom clusters: agitation, psychosis and mood disorders. Symptoms of agitation often include aggressiveness or irritability. Symptoms of psychosis are hallucinations – auditory or visual, and delusions. Mood disorders would include depression and anxiety.

Odds ratio

A ratio of the odds of having the disease of interest in a group with a particular exposure, symptom, or characteristic of interest, to the odds of disease in a group that does not have the exposure/symptom/characteristic. An odds ratio of 1 indicates that the disease is equally likely to occur in both groups. On odds ratio of 4 indicates that the disease is 4 times more likely to be present in the group that has the symptom or characteristic of interest, compared with the group that does not have this symptom.

Predictive Value (PPV)

Positive Predictive Value – the proportion of people with a positive test who have the disease; Negative Predictive Value – proportion of people with a negative test who are free of disease.


The total number of cases of the disease in the population at a given time, expressed as a proportion in which the number of cases is the numerator and the population at risk is the denominator.

Release signs

Primitive reflexes that are normally present in infants, including the suck, snout, palmomental, and grasp reflexes. They are seen in disorders that affect the frontal lobes, such as dementias, metabolic encephalopathies, closed head trauma, and hydrocephalus.

Remote/over-learned memory

The ability to remember people or events from the distant past, or over-learned information such as the days in the week or one’s birthday.


The processing of received information, and the retrieval of the information in response to a cue for use in a process or activity.


A strategy used in a population to detect a disease in individuals without signs or symptoms of that disease. Universal screening involves screening of all individuals in a certain category, for example, all persons age 65 and older.

Screening test

A brief instrument used to determine the likelihood of whether a disease may be present, and whether more comprehensive diagnostic testing may be needed. The predictive value of a screening test is influenced by the prevalence of the disease in the population. In universal screening, a screening test would be administered to all persons in a certain category (e.g. age 65+). In a case-finding approach, the screening test would be selectively administered when a patient has risk factors or presents with signs or symptoms of the disease.


The proportion of people who truly have a designated disorder who are so identified by the test. The test may consist of, or include, clinical observations. The proportion of truly diseased persons in the screened population who are identified as diseased by the screening test—that is, the true-positive rate.


The proportion of people who are truly free of a designated disorder who are so identified by the test. The test may consist of, or include, clinical observations. The proportion of truly nondiseased persons who are identified as such by the screening test —that is, the true-negative rate.


The ability to perceive the form of an object by using the sense of touch.


  1. American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision. Washington, DC: American Psychiatric Association, 2000.
  2. Guyatt G, Rennie D. User’s Guides to the Medical Literature: A manual for evidence-based clinical practice. Chicago: AMA Press, 2002.
  3. Holsinger T, Deveau J, Boustani M, Williams JW. Does this patient have dementia? JAMA. 2007;297(21):2391–404. [PubMed: 17551132]
  4. National Institute for Health and Clinical Excellence (NICE). Dementia: A NICE–SCIE Guideline on supporting people with dementia and their carers in health and social care. In: National Clinical Practice Guideline Number 42: The British Psychological Society and Gaskell; 2007. [PubMed: 21834193]
  5. Petersen RC, Stevens JC, Ganguli M, Tangalos EG, Cummings JL, DeKosky ST. Practice parameter: early detection of dementia: mild cognitive impairment (an evidence-based review). Report of the Quality Standards Subcommittee of the American Academy of Neurology. Neurology. 2001;56(9):1133–42. [PubMed: 11342677]
  6. Walker, HK. The suck, snout, palmomental, and grasp reflexes. Clinical Methods – the History, Physical, and Laboratory Examinations. Third Edition. Butterworth Publishers, 1990. [PubMed: 21250236]
  7. West S, King V, Carey TS, et al. Systems to rate the strength of scientific evidence: Evidence Report/Technology Assessment, Number 47. Rockville, MD: Agency for Healthcare Research and Quality. AHRQ Publication No. 02-E016, April 2002.
Cover of A Systematic Evidence Review of the Signs and Symptoms of Dementia and Brief Cognitive Tests Available in VA
A Systematic Evidence Review of the Signs and Symptoms of Dementia and Brief Cognitive Tests Available in VA [Internet].
Kansagara D, Freeman M.
Washington (DC): Department of Veterans Affairs (US); 2010 Apr.

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