The Mini-Cog, Clock Drawing Test, and the Mini-Mental State Examination in a German memory clinic: specificity of separation dementia from depression

Int Psychogeriatr. 2013 Jan;25(1):96-104. doi: 10.1017/S104161021200141X. Epub 2012 Aug 20.

Abstract

Background: The aim of this study was to assess the specificities of the Mini-Cog, the Clock Drawing Test (CDT), and the Mini-Mental State Examination (MMSE) against depression and healthy controls in a German Memory Clinic. Furthermore, we analyzed the specificities of all three screening instruments in dependence of actual depression severity.

Methods: Data from 142 depressed elderly, 438 dementia patients, and 64 healthy controls were retrospectively analyzed. The CDT and an extraction of the three-item recall of the MMSE were used to constitute the Mini-Cog algorithm. Depression severity was rated by either the Beck Depression Inventory (BDI) or the Geriatric Depression Scale (GDS) depending on the age of the patients.

Results: The Mini-Cog achieved a specificity of 79.6% against depressed elderly and 100.0% against healthy subjects (p < 0.001). Similarly, the specificities of the CDT (83.8%) and MMSE (92.3% at a cut-off ≤24 and 90.8% at ≤25, respectively) against healthy subjects were significantly higher than the specificities against depressed patients (each p < 0.05). Concerning the depressed patients, the MMSE demonstrated significant higher specificity than the Mini-Cog and the CDT, but also showed the lowest sensitivity for the detection of dementia. Surprisingly, the depression severity had no effect on the specificity of the Mini-Cog and the CDT, only the MMSE was susceptible for the depression severity.

Conclusion: Although the MMSE showed higher specificities, the weighting between the sensitivities and specificities in all tests prove again the Mini-Cog as a short, valid, and sensitive screening tool.

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Case-Control Studies
  • Dementia / diagnosis*
  • Dementia / psychology
  • Depression / diagnosis*
  • Depression / psychology
  • Female
  • Germany
  • Humans
  • Male
  • Middle Aged
  • Neuropsychological Tests* / standards
  • Psychiatric Status Rating Scales
  • Retrospective Studies
  • Sensitivity and Specificity
  • Severity of Illness Index