Mild cognitive impairment etiologic subtyping using pragmatic and conventional criteria: preliminary experience in the Florence VAS-COG clinic

Background Mild cognitive impairment (MCI) is an abnormal condition defined by the presence of cognitive decline not severe enough to fit dementia criteria. According to Winblad et al.'s criteria, the clinical distinction of MCI subtypes (amnestic/non-amnestic, single/multiple domain) is based on the cognitive profiling (conventional diagnosis) and infers possible different MCI etiologies. MCI prodromic of vascular dementia (Vasc-MCI) is thought to be characterized by a multiple domain profile. In our outpatient clinic (the "Florence VAS-COG clinic"), the diagnosis of MCI and of its different subtypes (vascular, degenerative, mixed) is based on a comprehensive evaluation of clinical and neuroimaging features (pragmatic diagnosis). Aims To compare the pragmatic and conventional diagnoses in terms of etiologic subtyping of MCI. Methods We retrospectively assessed the agreement between the two diagnoses in 30 MCI patients. Agreement was considered present when degenerative MCI was of the amnestic type (single or multiple domain) and Vasc-MCI was of the multiple domain type (amnestic or non-amnestic MCI). Results In 15/30 (50 %) patients, the diagnoses were in disagreement: 5/9 (56 %) patients diagnosed with a degenerative MCI type presented a non-amnestic cognitive profile (4 single domain and 1 multiple domain); 10/21 (48 %) Vasc-MCI were classified as non-amnestic single domain. Conclusions The application of MCI etiologic subtyping using pragmatic or conventional diagnoses leads to different results. In our setting, not all the Vasc-MCI patients have a multiple domain profile. Our preliminary study suggests that the cognitive profile of Vasc-MCI is more heterogeneous than previously suggested.