['Comparative analysis of subjects with mild cognitive impairment (MCI) diagnosed in a primary research setting and those seen in a tertiary care memory disorders clinic.', 'Subjects who received a diagnosis of MCI between July 1, 2005, and December 31, 2006, in a longitudinal research study of normal cognition (n = 48) and patients diagnosed in a tertiary care referral clinic (n = 34) were evaluated using similar methodologies. Comparative analyses of detailed medical, neurological and neuropsychological data are presented.', "The diagnosis of MCI was not accepted by 13 of 48 subjects (27%) classified as MCI in the primary research setting. Nondegenerative, potentially treatable causes of cognitive decline were found in 3 of 34 subjects (9%) seen in the tertiary referral clinic and in 11 of 35 subjects (31%) identified as MCI in the primary research setting (p = 0.02, Fisher's exact test). MCI subjects identified in the primary research setting were older than those referred to the memory clinic (mean +/- SD, 79.7 +/- 7.0 vs. 71.5 +/- 9.0 years, p < 0.0001, t test) and had more years of education (16.0 +/- 3.2 vs. 13.6 +/- 4.2 years, p < 0.01, t test). MCI subjects in the primary research setting appeared to be in a milder stage of disease, characterized by higher Mini-Mental State Examination scores (28.2 +/- 1.8 vs. 25.7 +/- 1.8, p < 0.0001), and a tendency towards single domain involvement, predominantly memory (mean number of domains involved, 1.0 vs. 2.5, p < 0.0001). More advanced stages of MCI, seen in the tertiary referral population, had additional involvement of attention (p < 0.0001, Fisher's exact test) and visuospatial domains (p < 0.0002, Fisher's exact test). Semiquantitative grading of hippocampal and medial temporal lobe atrophy did not differ between groups (p = 0.81, Mann-Whitney U test)."] Do clinical features of mild cognitive impairment differ in the research and tertiary clinic settings?