The Clinical Course of Early and Late Mild Cognitive Impairment

Abstract

IntroductionAmnestic mild cognitive impairment (MCI) can be classified as either early MCI (EMCI) or late MCI (LMCI) according to the severity of memory impairment. The aim of this study was to compare the prognosis and clinical course between EMCI and LMCI.MethodsBetween January 2009 and December 2017, a total of 418 patients with MCI and 146 subjects with normal cognition were recruited from a memory clinic. All the patients received at least two series of neuropsychological evaluations each year and were categorized as either EMCI or LMCI according to Alzheimer's Disease Neuroimaging Initiative 2 (ADNI2) criteria.ResultsIn total, our study included 161 patients with EMCI, 258 with LMCI, and 146 subjects with normal cognition as controls (NCs). The mean follow-up duration was 3.55 ± 2.18 years (range: 1–9). In a first-year follow-up assessment, 54 cases (32.8%) of EMCI and 16 (5%) of LMCI showed a normal cognitive status. There was no significant difference between the first year EMCI reverter and NCs in terms of dementia-free survival and further cognitive decline. However, first-year LMCI reverters still had a higher risk of cognitive decline during the following evaluations. Until the last follow-up, annual dementia conversion rates were 1.74, 4.33, and 18.6% in the NC, EMCI, and LMCI groups, respectively. The EMCI and LMCI groups showed a higher rate of progression to dementia (log-rank test, p < 0.001) than normal subjects. Compared with NCs, patients in the LMCI group showed a significantly faster annual decline in global cognition [annual rate of change for the mini-mental status examination (MMSE) score: −1.035, p < 0.001]) and all cognitive domains, while those in the EMCI group showed a faster rate of decline in global cognitive function (annual rate of change for the MMSE score: −0.299, p = 0.001).ConclusionIt is important to arrange follow-up visits for patients with MCI, even in the EMCI stage. One-year short-term follow-up may provide clues about the progression of cognitive function and help to identify relatively low-risk EMCI subjects.

Cognitive decline and alcohol consumption in the aging population—A longitudinal analysis of the Survey of Health, Ageing and Retirement in Europe

“…Regarding trajectories of cognitive decline, patients with neurodegenerative disorders typically show gradual deterioration of cognitive function over time and with progression of the disease [58]. However, knowledge on the specific time courses within different forms of neurodegeneration are still limited, and nonlinear and atypical progressions are postulated [59]: While most patients with AD and PD exhibit a cognitive decline over the course of a decade or more, cognitive functioning may remain stable in patients with MS [60][61][62]. In contrast to the previously discussed diagnoses, vascular dementia, exhibits a more ambiguous pattern and occurs more frequently in males under and females over the age of 80, who then tend to have a less favourable outcome than their male counterparts [63,64].…”

Establishment of a consensus protocol to explore the brain pathobiome in patients with mild cognitive impairment and Alzheimer's disease

“…Even so, CSF samples are routinely drawn in clinical centers around the world, particularly in cases of CNS disease of suspected infectious origin, and these are generally inspected by PCR techniques and/or culturing of microorganisms in vitro. Because MCI often shows progression to overt dementia (≈10% per year 111 ), CSF sampling does not constitute an insurmountable hurdle if it can guide clinical management. However, potential issues have been highlighted that complicate CSF analysis 105 .…”

Establishment of a consensus protocol to explore the brain pathobiome in patients with mild cognitive impairment and Alzheimer's disease: Research outline and call for collaboration

“…Even so, CSF samples are routinely drawn in clinical centers around the world, particularly in cases of CNS disease of suspected infectious origin, and these are generally inspected by PCR techniques and/or culturing of microorganisms in vitro. Because MCI often shows progression to overt dementia (~10% per year [83]), CSF sampling does not constitute an insurmountable hurdle if it can guide clinical management. However, potential issues have been highlighted that complicate CSF analysis [77].…”