Cambridge Cognition Examination (CAMCOG)

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.