The aim of this study was to evaluate the accuracy of neuropsychological assessment in predicting conversion from subjective cognitive decline (SCD) and mild cognitive impairment (MCI) to Alzheimer's disease (AD) and the effect of personality traits and cognitive reserve in progression from SCD to MCI. As part of a longitudinal, clinical-neuropsychological-genetic survey on SCD and MCI, 284 patients referred to our hospital between 1990 and 2017 were included. All patients underwent clinical-extensive neuropsychological evaluation and Apolipoprotein E genotyping; personality traits were assessed in a subgroup. Each patient underwent clinical-neuropsychological follow-up. Subjects with a follow-up shorter than two years were excluded. A total of 212 subjects were, after exclusions, considered: 26 out of 109 SCD subjects progressed to MCI (SCD-p), 15 converted to AD (SCD-c), and 68 remained stable (SCD-s). Of 103 MCI subjects, 39 converted to AD (MCI-c) and 64 remained stable (MCI-s). At baseline, SCD-c performed significantly worse than SCD-s in tests assessing long-term verbal memory. MCI-c showed worse performance on neuropsychological tests for short- and long-term verbal memory and for ecological evaluation of memory (RBMT). These tests provided good accuracy in distinguishing MCI-c and MCI-s. Emotional stability was significantly lower in SCD-s than in SCD-p while higher intellectual activities were associated with a lower risk of conversion to MCI. Our results suggest that memory neuropsychological tests may represent a reliable tool to estimate the risk of progression to AD. Personality and lifestyle factors could provide useful information to identify SCD subjects who may develop an objective cognitive impairment.

No abstract

Introduction Neurofilament light chain (NfL) is becoming increasingly notable in neurological diseases including AD, and it has been suggested as a new peripherical biomarker of neurodegeneration. We aimed to compare plasma NfL levels among Subjective Cognitive Decline (SCD), Mild Cognitive Impairment (MCI), and AD patients and to evaluate relationships between NfL and CSF biomarkers and neuropsychological scores. Materials and methods We enrolled 110 patients (34 SCD, 53 MCI, and 23 AD), who underwent clinical and neuropsychological evaluation, APOE genotyping, and plasma NfL analysis. Ninety-one patients underwent at least one amyloid burden biomarker (CSF and/or amyloid PET); 86 patients also underwent CSF phosphorylated-tau (p-tau) and total-tau (t-tau) measurement. Patients were classified as A + if they presented at least one positive amyloid biomarker or A− if not. Results NfL levels were significantly increased in AD and MCI compared to SCD patients. These differences depend on A status, e.g., SCD A + had lower NfLs than MCI A + but comparable with MCI A−. Similarly, MCI A + had higher NfL levels than MCI A−, but comparable with AD. NfL levels correlated with p-tau in SCD, with all CSF biomarkers in MCI patients. No correlations were found in AD subgroup. In SCD, NfL levels were negatively correlated with memory test scores. Conclusions Plasma NfL levels might be a promising biomarker for neurodegeneration to discriminate cognitive decline due to AD from other conditions causing cognitive impairment in prodromal stages. Considering correlations with CSF p-tau and memory tests in SCD, NfL might be a useful peripheral biomarker also in preclinical phases of AD.

Attention is the first non-memory domain affected in Alzheimer's disease (AD), before deficits in language and visuo-spatial function, and it is claimed that attention deficits are responsible for the difficulties with daily living in early demented patients. The aim of this longitudinal study in a group of 121 Caucasian, community-dwelling, mild-to-moderate AD patients (Mini-Mental State Examination (MMSE) score >17) was to detect which cognitive domains were most affected by the disease and whether one year treatment with cholinesterase inhibitors was more effective in preserving attention than memory. All subjects were evaluated by a neuropsychological battery including global measurements (MMSE, Information-Memory-Concentration Test) and tasks exploring verbal long-term memory, language, attention, and executive functions. The comparison between two evaluations, made 12 months apart, shows statistically significant differences, indicating deterioration compared to baseline, in the following tests: MMSE (with no gender differences), Composite Memory Score, Short Story Delayed Recall, Trail-Making Test A, Semantic Fluency Test, and Token Test. Conversely, there were no differences in the two evaluations of the Digit Span, Corsi Tapping Test, Short Story Immediate Recall, and Phonemic Fluency Tests. It appears that the treatment specifically attenuated the decline in tests assessing attention and executive functions. A stabilization of the ability to pay attention, with the ensuing positive effects on executive functions, recent memory, and information acquisition which depend on attention, appears to be the main neuropsychological mechanism through which the activation of the cholinergic system, resulting from cholinesterase inhibition, exerts its effect on cognition.