The early detection of dementia carries implications for clinical management of patients and their families, and it is of utmost concern if an effective pharmacological treatment is to be found. We report the final clinical diagnosis of 36 seniors who complained (or were accused) of forgetfulness. In the Initial Mini-Mental State Examination they scored 25 to 30 out of 30 points and could be diagnosed as having Mild Cognitive Impairment without dementia; preclinical Alzheimer's disease was suspected. Clinical observation (from 6 to 70 months, mean 31) showed that the clinical condition of 15 patients clearly worsened; these were diagnosed as likely Alzheimer's disease patients. Eleven suffered from emotional disturbances and improved with pharmacological and psychosocial treatment; ten of the patients had a static condition and remained in the Mild Cognitive Impairment category. We discuss the frontiers between normal aging, Mild Cognitive Impairment and Alzheimer's disease; we remark the difficulties in the differential diagnosis. Most of the patients with Alzheimer's disease were anosognosics with regard to the memory impairment; this could be a useful clinical point. We also underscore the usefulness of a neuropsychological assessment and the need for continued longitudinal evaluation of subjects with questionable dementia. In the next years, progress in neuropsychological, radiological and biological examinations will lead to improve diagnoses