3. Screening for Cognitive Impairment

Screening for Cognitive Impairment

This PatientPlus article is written for healthcare professionals so the language may be more technical than the condition leaflets. You may find the abbreviations list helpful.

General practitioners need to be able to recognise cognitive impairment and possible dementia using:

  • History taking.
  • Cognitive and mental state examination.
  • Physical examination and other appropriate investigations.
  • A review of medication in order to identify and minimise use of drugs, including over-the-counter products, which may adversely affect cognitive functioning.
NB: never delay referral for memory assessment on the basis that the results are only borderline-positive or where the patient appears to be coping well unaided - this is the group of patients likely to benefit most from intervention.

For more details see separate articles Dementia and Help and Advice for Relatives of Demented Patients.

The rest of this article deals with the screening tests that can be used to detect cognitive impairment. The limitation of such tests should be recognised and one UK study found that increased use of the tests was not reflected in an increase in the hospital diagnosis of dementia.[1]

  • Clinical cognitive assessment in those with suspected dementia should include examination of attention and concentration, orientation, short-term and long-term memory, praxis, language and executive function.
  • As part of this assessment, formal cognitive testing should be undertaken using a standardised instrument. For the purposes of screening in primary care, a test should be short, simple, easy to learn and perform with high sensitivities and specificities.
  • Those interpreting the scores of such tests should take full account of other factors known to affect performance, including educational level, skills, previous level of functioning and attainment, language and any sensory impairments, psychiatric illness or physical/neurological problems.
  • Formal neuropsychological testing should form part of the assessment in cases of mild or questionable dementia.
  • At the time of diagnosis of dementia and at regular intervals subsequently, assessment should be made for medical comorbidities and key psychiatric features associated with dementia, including depression and psychosis, to ensure optimal management of co-existing conditions.

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The General Practitioner Assessment of Cognition (GPCOG)

The GPCOG consists of cognitive test items in addition to historical questions asked of an informant (see GPCOG score calculator). It has been found to be reliable and superior to the Abbreviated Mental Test (AMT) and to the Mini Mental State Examination (MMSE), in detecting dementia.[2][3] The two-stage method of administering the GPCOG had a sensitivity of 0.85 and a specificity of 0.86.[4] Patient interviews took less than four minutes to administer and informant interviews less than two minutes.

The Mini Mental State Examination

The MMSE was developed by psychiatrists and is highly regarded. It has some methodological issues and may discriminate positively for those with a higher level of educational attainment.

The Six Item Cognitive Impairment Test (6CIT)

Developed in 1983, the 6CIT is relatively unknown, although because of recognition by The Royal College of General Practitioners together with new computerised versions, its usage is increasing.

The 6CIT is a much newer test than the AMT (see 'Abbreviated Mental Test', below) and it would appear to be culturally and linguistically translatable with good probability statistics; however, it is held back by its more complex scoring system. One study reported that it performed well as a screening instrument in older hospital patients[5] and more research is needed into its use in the wider community.

Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE)

When combined with cognitive tests, such as the MMSE, the IQCODE provides a useful overview and hence sensitivity and specificity as a screening test can be improved.[6]

The questionnaire asks how the patient compares today with ten years ago in various activities, eg remembering birthdays and recalling conversations.

Abbreviated Mental Test

The AMT is a quick to use screening test that was first introduced in 1972 but is less widely used today. Developed by geriatricians, this is probably the best known test in general hospital usage; however, it lacks validation in primary care and screening populations.

Its disadvantages are the ability to be confounded by intelligence, age, social class, sensitivity of hearing and history of stroke.[7][8] A four point AMT has been developed which should be easier to administer than the original ten point version and may obviate some of these problems.[9]

Test Your Memory (TYM) Test[10]

This is a useful screening test, particularly where clinician time is limited. The test involves:

  • Orientation.
  • Ability to copy a sentence.
  • Semantic knowledge.
  • Calculation.
  • Verbal fluency.
  • Similarities.
  • Naming.
  • Visuospatial abilities.
  • Recall of a copied sentence.

The ability to do the test is also scored.

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Further reading & references

  1. Menon R, Larner AJ; Use of cognitive screening instruments in primary care: the impact of national Fam Pract. 2011 Jun;28(3):272-6. Epub 2010 Nov 29.
  2. Brodaty H, Low LF, Gibson L, et al; What is the best dementia screening instrument for general practitioners to use? Am J Geriatr Psychiatry. 2006 May;14(5):391-400.
  3. Milne A, Culverwell A, Guss R, et al; Screening for dementia in primary care: a review of the use, efficacy and quality of measures. Int Psychogeriatr. 2008 Oct;20(5):911-26. Epub 2008 Jun 5.
  4. Brodaty H, Pond D, Kemp NM, et al; The GPCOG: a new screening test for dementia designed for general practice. J Am Geriatr Soc. 2002 Mar;50(3):530-4.
  5. Tuijl JP, Scholte EM, de Craen AJ, et al; Screening for cognitive impairment in older general hospital patients: comparison Int J Geriatr Psychiatry. 2011 Aug 27. doi: 10.1002/gps.2776.
  6. Mackinnon P et al; The Demegraph, January 2011
  7. MacKenzie DM, Copp P, Shaw RJ, et al; Brief cognitive screening of the elderly: a comparison of the Mini-Mental State Examination (MMSE), Abbreviated Mental Test (AMT) and Mental Status Questionnaire (MSQ). Psychol Med. 1996 Mar;26(2):427-30.
  8. Jitapunkul S, Pillay I, Ebrahim S; The abbreviated mental test: its use and validity. Age Ageing. 1991 Sep;20(5):332-6.
  9. Schofield I, Stott DJ, Tolson D, et al; Screening for cognitive impairment in older people attending accident and Eur J Emerg Med. 2010 Dec;17(6):340-2.
  10. Hancock P, Larner AJ; Test Your Memory test: diagnostic utility in a memory clinic population. Int J Geriatr Psychiatry. 2011 Sep;26(9):976-80. doi: 10.1002/gps.2639. Epub 2010
Original Author: Dr Laurence Knott Current Version: Peer Reviewer: Dr John Cox
Last Checked: 17/11/2011 Document ID: 2758  Version: 22 © EMIS

Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. EMIS has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. For details see our conditions.