Cambridge Cognition Examination (CAMCOG)

Evidence Reviewed as of before: 18-03-2009
Author(s): Sabrina Figueiredo, BSc
Contributor: Katherine Salter
Editor(s): Lisa Zeltzer, MSc OT; Nicol Korner-Bitensky, PhD OT; Elissa Sitcoff, BA BSc

Purpose

The Cambridge Cognition Examination (CAMCOG) is the cognitive and self-contained part of the Cambridge Examination for Mental Disorders of the Elderly (CAMDEX). The CAMCOG is a standardized instrument used to measure the extent of dementia, and to assess the level of cognitive impairment. The measure assesses orientation, language, memory, praxis, attention, abstract thinking, perception and calculation (Roth, Tym, Mountjoy, Huppert, Hendrie, Verma, et al., 1986).

In-Depth Review

Purpose of the measure

The Cambridge Cognition Examination (CAMCOG) is the cognitive and self-contained part of the Cambridge Examination for Mental Disorders of the Elderly (CAMDEX). The CAMCOG is a standardized instrument used to measure the extent of dementia, and to assess the level of cognitive impairment. The measure assesses orientation, language, memory, praxis, attention, abstract thinking, perception and calculation (Roth, Tym, Mountjoy, Huppert, Hendrie, Verma, et al., 1986).

Available versions

The CAMCOG was developed in 1986 by Roth, Tym, Mountjov, Huppert, Hendrie, Verma and Godddard. In 1999, Roth, Huppert, Mountjoy and Tym reviewed it and then published the CAMCOG-R. In 2000, de Koning, Dippel, van Kooten and Koudstall shortened the 67 items of the CAMCOG to 25 items, known as the Rotterdam CAMCOG (R-CAMCOG).

Features of the measure

Items:

The CAMCOG consists of 67 items, including the 19 items from the Mini Mental State Examination (MMSE) (Folstein, Folstein, & McHugh, 1975). It is divided into 8 subscales: orientation, language (comprehension and expression), memory (remote, recent and learning), attention, praxis, calculation, abstraction and perception (de Koning, van Kooten, Dippel, van Harskramp, Grobbee, Kluft, et al. 1998).

The orientation subscale is comprised of 10 items taken from the MMSE. In the language subscale, comprehension is assessed through nonverbal and verbal responses to spoken and written questions, and expression is assessed through tests of naming, repetition, fluency and definitions. The memory subscale assesses remote memory (famous events and people), recent memory (news items, prime minister, etc.), and learning (the recall and recognition of non-verbal and pictorial information learned incidentally as well as intentionally). Attention is assessed by serial sevens and counting backwards from 20. Praxis is assessed by copying, drawing, and writing as well as carrying out instructions. In the calculation subscale, the client is asked to perform an addition and a subtraction question involving money. For the abstraction subscale, the client is asked about similarities between an apple and a banana, a shirt and a dress, a chair and a table, and a plant and an animal. In the perception subscale, the client is asked to identify photographs of famous people and familiar objects from unusual angles, in addition to the tactile recognition of coins (Huppert, Jorm, Brayne, Girling, Barkley, Bearsdall et al., 1996).

The number of scored items for each subscale is as follows (de Koning et al., 1998; Huppert et al., 1996).

CAMCOG subscales Number of scored items
Orientation 10
Language
Comprehension
Expression
9
8
Memory
Learning
Recent
Remote
3
4
6
Concentration 2
Praxis 8
Calculation 2
Perception 3
Abstraction 4
Number of scored items 59

Items related to aphasia or upper extremity paresis may not be tested in all clients and depend on stroke severity.

Detailed administration guidelines are in the CAMCOG manual that can be obtained from the Cambridge University Department of Psychiatry.

Scoring:

The CAMCOG total score ranges from 0 to 107. Scores lower than 80 are considered indicative of dementia (de Koning et al., 1998; Roth et al., 1986). Among the 67 CAMCOG items, 39 are scored as ‘right’ or ‘wrong’; 11 are scored on a 3-point scale with ‘wrong’, ‘right to a certain degree’ or ‘completely right’ as response options; 9 items encompass questions or commands, and the score for each item is the sum of the correct answers; and finally 8 items are not scored. Five of the non-scored items are from the MMSE and they are not included in the total score because they are assessed in more detail by other CAMCOG items. The remaining 3 items are optional during the examination (de Koning, Dippel, van Kooten, & Koudstall, 2000; Huppert et al.,1996).

The maximum score per subscale is as follows (Huppert et al., 1996):

CAMCOG subscales Number of scored items
Orientation 10
Language
Comprehension
Expression
9
21
Memory
Learning
Recent
Remote
17
4
6
Concentration 4
Praxis 12
Calculation 5
Perception 11
Abstraction 8
Maximum Total Score 107

Time:

The CAMCOG takes 20 to 30 to administer and the R-CAMCOG takes 10 to 15 minutes to administer (de Koning et al, 1998; de Koning et al., 2000; Huppert et al., 1996).

Subscales:

The CAMCOG is comprised of 8 subscales:

  • Orientation
  • Language: subdivided into comprehensive and expressive language
  • Memory: subdivided into remote, recent and learning memory
  • Attention
  • Praxis
  • Calculation
  • Abstraction
  • Perception

Equipment:

The CAMCOG requires no specialized equipment. Only the test and a pencil are needed to complete the assessment.

The CAMCOG requires specialized equipment that are enclosed within its manual. The manual can be purchased from the Cambridge University Department of Psychiatry.

Alternative forms of the CAMCOG

  • Revised CAMCOG (CAMCOG-R): Published in 1999 by Roth, Huppert, Mountjoy and Tym, the CAMCOG-R improved the ability of the measure to detect certain types of dementia and to make clinical diagnoses based on the ICD-10 and DSM-IV. This version includes updated items from the remote memory subscale and the addition of items to assess executive function (Leeds, Meara, Woods & Hobson, 2001; Roth, Huppert, Mountjoy & Tym, 1999).
  • Rotterdam CAMCOG (R-CAMCOG): Published in 2000, the R-CAMCOG is a shortened version of the CAMCOG with 25 items. It takes 10 to 15 minutes to administer and is as accurate as the CAMCOG in screening for post-stroke dementia (de Koning et al., 2000).
  • General Practitioner Assessment of Cognition (GPCOG): Published in 2002 to be used in primary care settings, the GPCOG contains 9 cognitive and 6 informant items that were derived from the Cambridge Cognitive Examination, the Psychogeriatric Assessment Scale (Jorm, Mackinnon, Henderson, Scott, Christensen, Korten et al. 1995) and the instrumental Activities of Daily Living Scale (Lawton & Brody, 1969). The GPCOG takes 4 to 5 minutes to administer and appears to have a diagnostic accuracy similar to the Mini-Mental State Examination (Folstein, Folstein, & McHugh, 1975) in detecting dementia (Brodaty, Pond, Kemp, Luscombe, Harding, Berman et al., 2002).

Client suitability

Can be used with:

  • Clients with stroke
  • Clients with different types of dementia

Should not be used with:

  • The CAMCOG should not be used with clients with severe cognitive impairment.
  • Items related to aphasia and upper extremity paresis might not be tested on all clients and appropriate use depends on stroke severity.

In what languages is the measure available?

English and Dutch (de Koning et al., 2000).

Summary

What does the tool measure? The CAMCOG is a standardized instrument for diagnosis and grading of dementia.
What types of clients can the tool be used for? The CAMCOG can be used with, but is not limited to clients with stroke.
Is this a screening or assessment tool? Assessment
Time to administer The CAMCOG takes 20 to 30 minutes to administer.
Versions Revised CAMCOG (CAMCOG-R); Rotterdam-CAMCOG (R-CAMCOG); General Practitioner Assessment of Cognition (GPCOG)
Other Languages English; Dutch
Measurement Properties
Reliability
  • No studies have examined the internal consistency of the CAMCOG in clients with stroke.
  • No studies have examined the reliability of the CAMCOG in clients with stroke.
Validity

Content:

No studies have examined the content validity of the CAMCOG in clients with stroke.

One study examined the content validity of the R-CAMCOG by reporting the steps for generating the shortened version of the CAMCOG.

Criterion:

Concurrent Validity:

No studies have examined the concurrent validity of the CAMCOG.

Predictive Validity:

Six studies examined the predictive validity of the CAMCOG and reported that the CAMCOG can be predicted by age, the R-CAMCOG, the Mini-Mental State Examination and cognitive and emotional impairments. Additionally, the CAMCOG was an excellent predictor of dementia 3 to 9 months post-stroke. However, the CAMCOG was not able to predict QOL in clients with stroke and is not predicted by the Functional Independence Measure.

Construct:

Convergent validity:

One study examined the convergent validity of the CAMCOG in clients with stroke and reported excellent correlations between the CAMCOG and the R-CAMCOG and the Mini-Mental State Examination shortly after and 1 year post-stroke. Correlations between the CAMCOG and the Functional Independence Measure range from adequate after stroke to poor at 1 year post-stroke.

One study examined the convergent validity of the CAMCOG-R and reported excellent correlations between the CAMCOG-R and the Raven Test and the Weigl Test and poor correlations between the CAMCOG-R and the Geriatric Depression Scale and the Barthel Index using Pearson correlation.

Known Groups:

Two studies using student t-test examined known groups validity of the CAMCOG and reported that the CAMCOG is able to distinguish between clients with or without dementia as well as aphasia severity in clients with stroke.

Floor and ceiling effect One study examined the floor / ceiling effects of the CAMCOG in clients with stroke and reported that 14 items showed ceiling effects but no floor effects
Does the tool detect change in patients?
  • No studies have examined the responsiveness of the CAMCOG in clients with stroke.
  • One study examined the responsiveness of the CAMCOG-R and reported that at follow-up scores changes were all statistically significant (p<0.01).
Acceptability Items related to aphasia and upper extremity paresis might not be tested on all clients due to stroke severity.
Feasibility The instructions for administration and coding must be followed closely (Ruchinskas and Curyto, 2003).
How to obtain the tool? The CAMCOG can be obtained by purchasing the entire CAMDEX from the Cambridge University Department of Psychiatry

Psychometric Properties

Overview

We conducted a literature search to identify all relevant publications on the psychometric properties of the Cambridge Cognition Examination (CAMCOG) in individuals with stroke. We identified 6 studies on the CAMCOG, 1 on the CAMCOG-R and 1 on the R-CAMCOG.

Floor/Ceiling Effects

de Koning, Dippel, van Kooten and Koudstaal (2000) analyzed the floor and ceiling effects of the CAMCOG in 300 clients with stroke. A ceiling effect was found in 2 out of 10 orientation items, 8 out 17 language items, 2 out of 13 memory items, 1 out of 8 praxis items, and 1 out of 3 perception items, with more than 20% of participants scoring the maximum score. No floor effect was observed in the CAMCOG.

Reliability

No studies have examined the reliability of the CAMCOG in clients with stroke.

Validity

Content:

No studies have examined the content validity of the CAMCOG in clients with stroke.

de Koning et al. (2000) analyzed CAMCOG scores from 300 clients with stroke and reduced the 59 items of the CAMCOG to the 25 items of the R-CAMCOG. Initially, item reduction was performed by removing 14 items with ceiling effects on the CAMCOG. Next, the language, attention, praxis, and calculation subscales were eliminated due to their low diagnostic accuracy. Finally, items with a very low or very high inter-item correlation were removed.

Criterion:

Concurrent:

No studies have examined the concurrent validity of the CAMCOG in clients with stroke.

Predictive:

Kwa, Limburg, Voogel, Teunisse, Derix and Hijdra (1996a) examined whether age, educational level, side and volume of the infarct, aphasia severity, and motor function predicted CAMCOG scores at 3 months after stroke in 129 clients. A cut-off of 80 was used to discriminate between normal and abnormal cognitive function. Based on regression analysis with these above-mentioned variables included, age appeared to be the best predictor of CAMCOG scores 3 months post-stroke.

Note: The timeline for the baseline measurements were not reported in the study.

Kwa, Limburg and de Haan (1996b) verified the ability of the CAMCOG, the Rankin Scale (Rankin, 1957), the Barthel Index (Mahoney & Barthel, 1965), the Motricity Index (Colin & Wade, 1990), aphasia severity, age, educational level, volume and side of the infarct to predict quality of life in 97 clients with stroke. Linear regression analysis indicated that quality of life is best predicted by the Rankin Scale, volume of infarct and aphasia severity.

Note: The timeline for all the measurements were not reported in the study.

de Koning, van kooten, Dippel, van Harskamp, Grobbee, Kluft, et al. (1998) analyzed the ability of the CAMCOG and the Mini-Mental State Examination (MMSE – Folstein, Folstein, & McHugh, 1975) measured shortly after stroke to predict dementia measured 3 to 9 months later in 300 clients with stroke. Predictive validity was calculated by use of c-statistics to calculate the area under the Receiver Operating Characteristic (ROC) curve. The ability of the CAMCOG (AUC = 0.95) and the MMSE (AUC = 0.90) to predict dementia after stroke were both considered excellent. These results suggest that the percentage of patients correctly classified according to their dementia level at 3 to 9 months post-stroke is only slightly higher when using the CAMCOG over the MMSE.

de Koning et al. (2000) examined whether the CAMCOG and the R-CAMCOG, measured at hospital admission predicted dementia at 3 to 9 months post-stroke in 300 clients. Predictive validity, as calculated using c-statistics to estimate the area under the Receiver Operating Characteristic (ROC) curve, were all excellent for the CAMCOG (AUC = 0.95) and the CAMCOG-R (AUC = 0.95). These results suggest that the percentage of patients correctly classified according to their dementia level at 3 to 9 months post-stroke is the same when using the CAMCOG and the R-CAMCOG. Additionally, when using a cut-off of 77 for the CAMCOG and 33 for the R-CAMCOG, both measures showed a sensitivity of 91% and the specificity was 88% and 90%, respectively.

van Heugten, Rasquin, Winkens, Beusmans, and Verhey (2007) estimated the ability of a checklist of cognitive and emotional impairments measured 6 months post-stroke to predict the CAMCOG and the Mini-Mental State Examination (MMSE – Folstein, Folstein, & McHugh, 1975) scores at 12 months in 69 clients. Regression analysis showed that cognitive and emotional impairments explained 31% of the variance on the MMSE and 22% of the variance on the CAMCOG. These results suggest that cognitive and emotional impairments were able to predict the scores of both measures.

Winkel-Witlox, Post, Visser-Meily, and Lindeman (2008) analyzed the ability of the R-CAMCOG, the Mini-Mental State Examination (MMSE – Folstein, Folstein, & McHugh, 1975) and the Functional Independence Measure (FIM – Keith, Granger, Hamilton, & Sherwin, 1987) to predict the CAMCOG in 169 clients. All four outcomes measures were collected shortly after and 1 year post-stroke. Regression analysis showed that after stroke the R-CAMCOG explained 83% of variance on the CAMCOG, the MMSE explained 53% and the FIM 11%. At 1 year post-stroke the R-CAMCOG explained 82% of variance on the CAMCOG, the MMSE explained 57% and the FIM only 04%. These results suggest that the R-CAMCOG is the best predictor of the CAMCOG among these independent variables.

Construct:

Convergent/Discriminant:

Winkel-Witlox et al. (2008) examined the convergent validity of the CAMCOG by comparing it to R-CAMCOG, the Mini-Mental State Examination (MMSE – Folstein, Folstein, & McHugh, 1975) and the Functional Independence Measure (FIM – Keith, Granger, Hamilton, & Sherwin, 1987) in 169 clients with stroke. Shortly after and at 1 year post-stroke correlations between the CAMCOG and the R-CAMCOG and the MMSE were all excellent (rho1 = 0.92; 066, rho2 = 0.92; 069, respectively). Correlations between the CAMCOG and the FIM was adequate shortly after stroke (rho1 = 0.35) and poor after 1 year (rho2 = 0.27).

Leeds, Meara, Woods and Hobson (2001) analyzed the construct validity of the CAMCOG-R by comparing it to the Raven Test (Raven, 1982), the Weigl Test (Grewal, Haward, & Davies, 1986), the Geriatric Depression Scale (Sheikh & Yesavage, 1986) and the Barthel Index (Mahoney & Barthel, 1965) in 83 clients with stroke. Correlations as calculated using Pearson correlations were excellent between the CAMCOG-R and the Raven Test (r = 0.75) and the Weigl Test (r = 0.70). Correlations between the CAMCOG-R and the Geriatric Depression Scale (r = -0.30) and the Barthel Index (r = 0.20) were poor.

Known groups.

de Koning et al. (1998) analyzed whether the CAMCOG is able to distinguish between individuals with dementia from those without dementia in 300 clients with stroke. Known groups validity, as calculated using student t-test, showed that the CAMCOG was able to discriminate clients with dementia from those without dementia. These results demonstrated that clients with dementia have statistically significant lower scores on the CAMCOG.

Kwa et al. (1996a) verified the ability of the CAMCOG to discriminate between clients without aphasia and those with severe aphasia in 129 clients with stroke. Known groups validity, as calculated using the student t-test, showed that the CAMCOG was able to differentiate between aphasia severity.

Responsiveness

No studies have examined the responsiveness of the CAMCOG in clients with stroke.

Leeds et al. (2001) examined the responsiveness of the CAMCOG-R in 83 clients with stroke. Participants were assessed at baseline and 63 days later. At follow-up, changes on the CAMCOG-R scores were all statistically significant (p<0.01). These results suggest that the CAMCOG-R appears sensitive to change in cognitive status of clients with stroke.

References

  • Brodaty, H., Pond, D., Kemp, N.M., Luscombe, G., Harding, L., Berman, K. et al. (2002). The GPCOG: A new screening test for dementia designed for general practice. Journal of the American Geriatrics Society, 50, 530-534.
  • Collin, C. & Wade, D. (1990). Assessing motor impairment after stroke: A pilot reliability study. J Neurology Neurosurg Psychiatry, 53, 576-579.
  • de Koning, I., Dippel, D.W.J., van Kooten, F. & Koudstaal, P.J. (2000). A short screening instrument for poststroke dementia: The R-CAMCOG. Stroke, 31, 1502-1508.
  • de Koning, I., van Kooten, F., Dippel, D.W.J., van Harskamp, F., Grobbee, D.E., Kluft, C. & Koudstaal, P.J. (1998). The CAMCOG: A useful screening instrument for dementia in stroke patients. Stroke, 29, 2080-2086.
  • Folstein, M.F., Folstein, S. E. & McHugh, P. R. (1975). “Mini-mental state”. A practical method for grading the cognitive state of patients for the clinician. J Psychiatr Res, 12(3), 189-198.
  • Grewal, B., Haward, L. & Davies, I. (1986). Color and form stimulus values in a test of dementia. IRCS Med Sci, 14, 693-694.
  • Huppert, F.A., Jorm, A.F., Brayne, C., Girling, D.M., Barkeley, C., Bearsdall, et al. (1996). Psychometric properties of the CAMCOG and its efficacy in the diagnosis of dementia. Aging, Neuropsychology, and Cognition, 3, 201-214.
  • Jorm, A.F., Mackinnon, A.J., Henderson, A.S., Scott, H., Christensen, H., Korten, A.E., et al. (1995). The Psychogeriatric Assessment Scales: A multidimensional alternative to categorical diagnoses of dementia and depression in the elderly. Psychol Med, 25, 447-460.
  • Keith, R.A., Granger, C.V., Hamilton, B.B., & Sherwin, F.S. (1987). The functional independence measure: A new tool for rehabilitation. Adv Clin Rehabil, 1, 6-18.
  • Kwa, V.I.H., Limburg, M. & de Haan, R.J. (1996b). The role of cognitive impairment in the quality of life after ischaemic stroke. J Neurol, 243, 599-604.
  • Kwa, V.I.H., Limburg, M., Voogel, A.J., Teunisse, S., Derix, M.M.A. & Hijdra, A. (1996a). Feasibility of cognitive screening of patients with ischaemic stroke using the CAMCOG: a hospital based study. J Neurol, 243, 405-409.
  • Lawton, M.P. & Brody, E.M. (1969). Assessment of older people: Self-maintaining and instrumental activities of daily living. Gerontologist, 9, 179-186.
  • Leeds, L., Meare, R.J., Woods, R. & Hobson, J.P. (2001). A comparison of the new executive functioning domains of the CAMCOG-R with existing tests of executive function in elderly stroke survivors. Age and Ageing, 30, 251-254.
  • Mahoney, F. & Barthel, D. (1965). Functional evaluation: The Barthel Index. MD State J, 14, 61-65.
  • Rankin, J. (1957). Cerebral vascular accidents in patients over the age of 60. Scott Med J, 2, 200-215.
  • Raven, J.C. (1982). Revised manual for Raven’s Coloured Progressive Matrices. Windsor, UK: NFER-Nelson.
  • Roth, M., Huppert, F., Mountjoy, C., & Tym, E. (1999). The Cambridge Examination for Mental Disorders of the Elderly – Revised. Cambridge: Cambridge University Press.
  • Roth, M., Tym, E., Mountjoy, C., Huppert, F.A., Hendrie, H., Verma, S. et al. (1986). CAMDEX: A standardized instrument for the diagnosis of mental disorder in the elderly with special reference to the early detection of dementia. British Journal of Psychiatry, 149, 698-709.
  • Ruchinskas, R.A. & Curyto, K. (2003). Cognitive screening in geriatric rehabilitation. Rehabilitation Psychology, 48(1), 14-22.
  • Sheikh, J.A. & Yesavage, J.A. (1986). Geriatric depression scale (GDS): Recent findings and development of a shorter version. Clinical Gerontologist, 5, 165-172.
  • Winkel-Witlox, A.C.M.Te, Post, M.W.M., Visser-Meily, J.M.A., & Linderman, E. (2008). Efficient screening of cognitive dysfunction in stroke patients: Comparison between the CAMCOG and the R-CAMCOG, Mini-Mental State Examination and Functional Independence Measure-cognition score. Disability and Rehabilitation, 30(18), 1386-1391.
  • van Heugten, C., Rasquin, S., Winkens, I., Beusmans, G., & Verhey, F. (2007). Checklist for cognitive and emotional consequences following stroke (CLCE-24): Development, usability and quality of the self-report version. Clinical Neurology and Neurosurgery, 109, 257-262.

See The Measure

How to obtain the CAMCOG

The CAMCOG can be obtained by purchasing the entire CAMDEX from the Cambridge University Department of Psychiatry.

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