Neuropsychological Performance and Conversion to Alzheimer’s Disease in Early- Compared to Late-Onset Amnestic Mild Cognitive Impairment: CREDOS Study

Abstract

Background: Amnestic mild cognitive impairment (aMCI) is regarded as a prodromal stage of Alzheimer’s disease (AD). Given that patients with early-onset AD (EOAD) and with late-onset AD (LOAD) are known to have different clinical courses, symptoms and neuroimaging findings, early-onset (EOMCI) and late-onset aMCI (LOMCI) might be expected to have similar differences as EOAD versus LOAD. Methods: Our study involving 425 patients with aMCI (124 EOMCI, 301 LOMCI), who were followed for around 1.5 years, and 958 normal control subjects (NC) investigated neuropsychological characteristics and prediction of progression to AD in patients with EOMCI versus LOMCI. Neuropsychological scores were compared between EOMCI, LOMCI and NC with analyses of covariance controlling age, gender, education and disease duration. The risk of AD conversion was evaluated by Cox proportional hazard analyses. Results: The baseline neuropsychological performances were comparable between EOMCI and LOMCI. Visuospatial memory for EOMCI and verbal memory scores for LOMCI were significant predictors of AD conversion. Conclusion: Our study indicates that EOMCI with visuospatial memory impairment, which implies underlying right predominant pathology, and LOMCI with poor verbal memory, which suggests underlying left predominant pathology, are individual conditions at an increased risk of conversion to AD.

Detecting Early Preclinical Alzheimer's Disease via Cognition, Neuropsychiatry, and Neuroimaging: Qualitative Review and Recommendations for Testing

“…The mental control subtest of the Wechsler Memory Scale combined with RAVLT delayed recall was shown to have a classification accuracy of 89% in memory-impaired non-demented patients, two years before AD diagnosis [30]. Similarly, high predictive accuracy was found when combining episodic memory with naming [38,39] or verbal fluency [27,40,41]. Particularly high prediction values were obtained when combin-ing memory with more than one other domain.…”

Sex differences in cognitive impairment and Alzheimer’s disease

“…Mild cognitive impairment (MCI) is a clinical condition often associated with early stage of AD. A study of 425 MCI patients showed that early onset MCI patients suffer more visuospatial memory impairment, while a late onset of MCI showed more verbal memory problems; however, both are individual conditions at an increased risk of conversion to AD [106]. Moreover, other studies also reported no significant differences in the demographic characteristics of patients with mixed dementia and AD, where patients with mixed dementia were significantly more impaired than AD patients in global cognitive composite, attention and visuoconstruction [107].…”

Neuropsychological Criteria for Mild Cognitive Impairment in the Framingham Heart Study’s Old-Old

“…Increased variability in neuropsychological performance in the old-old presents a unique challenge when diagnosing MCI, and individuals with early- versus late-onset MCI show differences in neuropsychological predictors of conversion to AD [12]. Furthermore, we have previously shown that the neuropsychological profiles associated with dementia detection in the very-old (mean age > 80 years) differ from those in the young-old (mean age < 70 years), with the very-old AD group outperforming the young-old AD group when age-adjusted standardized scores were applied, despite the groups achieving comparable raw scores [13].…”