Mild cognitive impairment: experience from a memory clinic.

Mild cognitive impairment (MCI) is sometimes a transition between normal aging and dementia. We investigated the occurrence of MCI in a population referred to a memory clinic. The criteria used to diagnose the state were similar to those used by Petersen et al. in many previous publications. A clinical evaluation after approximately 3 years was also performed. In a subsample of 43 subjects, we found that, during 1 year, 37% (136/402) of all investigated subjects were patients with MCI. After a mean follow-up time of 3 years, 11% (5/43) showed cognitive improvement, while 53% (23/43) were stable and showed no cognitive decline or improvement. Fifteen out of 42 patients (35%) deteriorated and were diagnosed as demented during the same time. We conclude that MCI is a heterogeneous concept and that the outcome at follow-up is dependent on which population is studied and how MCI has been defined.