The consideration of Subjective Cognitive Decline (SCD) as a preclinical stage of AD remains still a matter of debate. Alpha band alterations represent one of the most significant changes in the electrophysiological profile of AD. In particular, AD patients exhibit reduced alpha relative power and frequency. We used alpha band activity measured with MEG to study whether SCD and MCI elders present these electrophysiological changes characteristic of AD, and to determine the evolution of the observed alterations across AD spectrum. The total sample consisted of 131 participants: 39 elders without SCD, 41 elders with SCD and 51 MCI patients. All of them underwent MEG and MRI scans and neuropsychological assessment. SCD and MCI patients exhibited a similar reduction in alpha band activity compared with the no SCD group. However, only MCI patients showed a slowing in their alpha peak frequency compared with both SCD and no SCD. These changes in alpha band were related to worse cognition. Our results suggest that AD-related alterations may start in the SCD stage, with a reduction in alpha relative power. It is later, in the MCI stage, where the slowing of the spectral profile takes place, giving rise to objective deficits in cognitive functioning.
SCD elders exhibit a significant network disruption, showing intermediate values between HC and MCI groups in multiple parameters. These results highlight the relevance of cognitive concerns in the clinical setting and suggest that network disorganization in AD could start in the preclinical stages before the onset of cognitive symptoms.
Memory complaints are a heterogeneous phenomenon. Our results confirm that multimorbidity, polypharmacy, greater use of health services, pain, and poor self-perceived health are associated with SMC. We identified two risk groups with a high percentage of complaints and a healthy group with a low percentage. Detecting these factors and these risk and healthy groups is useful in achieving proper patients management.
The present study explores the role of cognitive reserve, executive functions, and working memory (WM) span, as factors that might explain training outcomes in cognitive status. Eighty-one older adults voluntarily participated in the study, classified either as older adults with subjective cognitive decline or cognitively intact. Each participant underwent a neuropsychological assessment that was conducted both at baseline (entailing cognitive reserve, executive functions, WM span and depressive symptomatology measures, as well as the Mini-Mental State Exam regarding initial cognitive status), and then 6 months later, once each participant had completed the training program (Mini-Mental State Exam at the endpoint). With respect to cognitive status the training program was most beneficial for subjective cognitive decline participants with low efficiency in inhibition at baseline (explaining a 33% of Mini-Mental State Exam total variance), whereas for cognitively intact participants training gains were observed for those who presented lower WM span.
In 4 experiments, picture-word translation was studied in Spanish-English bilinguals and English monolinguals. In Experiment 1, bilinguals drew pictures or wrote English or Spanish words for picture or English or Spanish word stimuli. Equivalent increases in production onset latency for cross-language/modality translation were found. In Experiment 2, bilinguals and monolinguals drew pictures or wrote English words for picture or English word stimuli. Cross-modality translation equivalence was replicated, though bilinguals were slower than monolinguals overall. In Experiment 3, bilinguals and monolinguals were equivalent when they drew or wrote names from pictures as blocked tasks. In Experiment 4, bilinguals replicated Experiment 1 but were faster for blocked than mixed tasks, indicating that stimulus-processing uncertainty slows them. Results support a revised concept mediation model, with equivalent semantic access for pictures and words for bilinguals and monolinguals.If a picture is worth 1,000 words, is it worth 2,000 words to a bilingual person? Since the work of Cattell (1887), there has been an interest in determining how bilinguals translate from one language to another and how they name pictures in one of their languages (see also Snodgrass, 1993). Two general models have been proposed to specifically account for how bilinguals process their lexical and pictorial knowledge in speeded tasks (see Potter, So, Von Eckardt, & Feldman, 1984): the concept mediation model and the word association model. Intrinsic to a discussion of these models has been the treatment of bilinguals' two languages, the first-learned or dominant language (LI) and the secondlearned or subordinate language (L2; see Bentahila & Davies, 1992). Both models posit that within-language conditions (i.e., word reading) incur less latency than cross-language or cross-modality translation conditions because additional stages beyond those for grapheme-tophoneme transformation are not needed (see Glaser, 1992;Levelt et al., 1991;Theios & Amrhein, 1989).The differences between the two models lie in the processing assumptions for these translation conditions.
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