Brief Tests such as the Clock Drawing Test or Cognistat Can Be Useful Predictors of Conversion from MCI to Dementia in the Clinical Assessment of Outpatients

Abstract

Background: The identification of patients with mild cognitive impairment (MCI) who are at high risk of conversion to dementia is a challenging clinical task. Aims: To investigate whether simple cognitive screening tests can predict the conversion from MCI to dementia and to study the impact of different patient characteristics on the progression rate. Methods: A retrospective, longitudinal study of 90 outpatients diagnosed with MCI at a psychogeriatric clinic in Norway was conducted. Baseline scores on the Mini-Mental State Examination (MMSE), Clock Drawing Test (CDT), and Neurobehavioral Cognitive Status Examination (Cognistat) were related to ICD-10 diagnosis during 46 months. The influence of demographic, life situational, and clinical data were analyzed. Results: Sixty-four patients were diagnosed with dementia, significantly more females (82%) than males (50%) (p < 0.01). Low scores on the CDT [adjusted hazard ratio (HR) = 0.85; 95% CI 0.73-0.97; p = 0.020] and Cognistat (adjusted HR = 0.78; 95% CI 0.65-0.93; p = 0.007) significantly predicted the conversion from MCI to dementia, whereas the MMSE score did not. Conclusions: A high proportion of patients converted from MCI to dementia within 46 months, and females seem to be at higher risk. CDT and Cognistat significantly predicted the conversion from MCI to dementia and are therefore considered appropriate tests in clinical practice.