Pollen, micro-charcoal, and non-pollen palynomorph counts of Dead Sea core 5017-1-A (88-14 ka BP)

The southern Levant is a key region for studying vegetation developments in relation to climate dynamics and hominin migration processes in the past due to the sensitivity of the vegetation to climate variations and the long history of different anthropogenic occupation phases. However, paleoenvironmental conditions in the southern Levant during the Late Pleistocene were still insufficiently understood. Therefore, we investigated the vegetation and fire history of the Dead Sea region during the last glacial period. We present a new palynological study conducted on sediments of Lake Lisan, the last glacial precursor of the Dead Sea. The sediments were recovered from the center of the modern Dead Sea within an ICDP campaign. The palynological results suggest that Irano-Turanian steppe and Saharo-Arabian desert vegetation prevailed in the Dead Sea region during the investigated period (ca. 88,000–14,000 years BP). Nevertheless, Mediterranean woodland elements significantly contributed to the vegetation composition, suggesting moderate amounts of available water for plants. The early last glacial was characterized by dynamic climate conditions with pronounced dry phases and high but unstable fire activity. Anatomically modern humans entered the southern Levant during a climatically stable phase (late MIS 4–MIS 3) with diverse habitats, constant moisture availability, and low fire activity. MIS 2 was the coldest phase of the investigated timeframe, causing changes in woodland composition and a widespread occurrence of steppe. We used a biome modeling approach to assess regional vegetation patterns under changing climate conditions and to evaluate different climate scenarios for the last glacial Levant. The study provides new insights into the environmental responses of the Dead Sea region to climate variations through time. It contributes towards our understanding of the paleoenvironmental conditions in the southern Levant, which functioned as an important corridor for human migration processes

Cognitive Complaints in Memory Clinic Patients and in Depressive Patients: An Interpretative Phenomenological Analysis

Background and Objectives Cognitive complaints are discussed as early signs of Alzheimer's disease (AD). However, they are also very common in cognitively normal older adults and in patients with depression. Qualitative, interview-based approaches might be useful to identify those features of cognitive complaints specific for the experiences of cognitive decline in preclinical or prodromal AD versus those complaints typically reported by depressed patients. Research Design and Methods A semi-structured interview was administered to 21 cognitively normal older adults (HC), 18 nondemented memory clinic patients (MC), and 11 patients with a major depression (MD), all above 55 years. Interpretative phenomenological analysis (IPA) was applied to the interview transcripts to develop emerging complaint themes in each group. To identify thematic correspondence and possibly novel, hitherto unappreciated themes, the extracted complaint categories were compared with the neurocognitive domains in the DSM-5 and the content of the Everyday Cognition questionnaire (E-Cog). Results IPA yielded 18 cognitive complaint categories in MC, 10 in depressive patients, and 10 categories in the HC group. Several themes were common across groups, but some were group-specific, for example, spatial disorientation was only reported in MC patients. Some of these MC-specific themes were neither represented by DSM-5 domains nor by the E-Cog. Discussion and Implications We report a comprehensive qualitative description of cognitive complaints in old age which could help to develop questionnaires or structured interviews to better assess AD-related subjective cognitive decline. This may help to increase specificity in selecting high-risk subjects in research settings and improve clinical judgment of diverse cognitive complaints types mentioned by their patients

Disentangling the relationship of subjective cognitive decline and depressive symptoms in the development of cognitive decline and dementia

Introduction Subjective cognitive decline (SCD) and depressive symptoms (DS) frequently co-occur prior to dementia. However, the temporal sequence of their emergence and their combined prognostic value for cognitive decline and dementia is unclear. Methods Temporal relationships of SCD, DS and memory decline were examined by latent difference score modeling in a high-aged, population-based cohort (N = 3217) and validated using Cox-regression of dementia-conversion. In 334 cognitively unimpaired SCD-patients from memory-clinics, we examined the association of DS with cognitive decline and with cerebrospinal fluid (CSF) Alzheimer's disease (AD) biomarkers. Results In the population-based cohort, SCD preceded DS. High DS were associated with increased risk of dementia conversion in individuals with SCD. In SCD-patients from memory-clinics, high DS were associated with greater cognitive decline. CSF Ass42 predicted increasing DS. Discussion SCD typically precedes DS in the evolution to dementia. SCD-patients from memory-clinics with DS may constitute a high-risk group for cognitive decline. Highlights Subjective cognitive decline (SCD) precedes depressive symptoms (DS) as memory declines. Emerging or persistent DS after SCD reports predict dementia. In SCD patients, more amyloid pathology relates to increasing DS. SCD patients with DS are at high risk for symptomatic progression

Which features of subjective cognitive decline are related to amyloid pathology? Findings from the DELCODE study

BackgroundSubjective cognitive decline (SCD) has been proposed as a pre-MCI at-risk condition of Alzheimer's disease (AD). Current research is focusing on a refined assessment of specific SCD features associated with increased risk for AD, as proposed in the SCD-plus criteria. We developed a structured interview (SCD-I) for the assessment of these features and tested their relationship with AD biomarkers.MethodsWe analyzed data of 205 cognitively normal participants of the DELCODE study (mean age=68.9years; 52% female) with available CSF AD biomarkers (A beta-42, p-Tau181, A beta-42/Tau ratio, total Tau). For each of five cognitive domains (including memory, language, attention, planning, others), a study physician asked participants about the following SCD-plus features: the presence of subjective decline, associated worries, onset of SCD, feeling of worse performance than others of the same age group, and informant confirmation. We compared AD biomarkers of subjects endorsing each of these questions with those who did not, controlling for age. SCD was also quantified by two summary scores: the number of fulfilled SCD-plus features, and the number of domains with experienced decline. Covariate-adjusted linear regression analyses were used to test whether these SCD scores predicted abnormality in AD biomarkers.ResultsLower A beta-42 levels were associated with a reported decline in memory and language abilities, and with the following SCD-plus features: onset of subjective decline within 5years, confirmation of cognitive decline by an informant, and decline-related worries. Furthermore, both quantitative SCD scores were associated with lower A beta 42 and lower A beta 42/Tau ratio, but not with total Tau or p-Tau181.ConclusionsFindings support the usefulness of a criterion-based interview approach to assess and quantify SCD in the context of AD and validate the current SCD-plus features as predictors of AD pathology. While some features seem to be more closely associated with AD biomarkers than others, aggregated scores over several SCD-plus features or SCD domains may be the best predictors of AD pathology

Which features of subjective cognitive decline are related to amyloid pathology? Findings from the DELCODE study

BackgroundSubjective cognitive decline (SCD) has been proposed as a pre-MCI at-risk condition of Alzheimer's disease (AD). Current research is focusing on a refined assessment of specific SCD features associated with increased risk for AD, as proposed in the SCD-plus criteria. We developed a structured interview (SCD-I) for the assessment of these features and tested their relationship with AD biomarkers.MethodsWe analyzed data of 205 cognitively normal participants of the DELCODE study (mean age=68.9years; 52% female) with available CSF AD biomarkers (A beta-42, p-Tau181, A beta-42/Tau ratio, total Tau). For each of five cognitive domains (including memory, language, attention, planning, others), a study physician asked participants about the following SCD-plus features: the presence of subjective decline, associated worries, onset of SCD, feeling of worse performance than others of the same age group, and informant confirmation. We compared AD biomarkers of subjects endorsing each of these questions with those who did not, controlling for age. SCD was also quantified by two summary scores: the number of fulfilled SCD-plus features, and the number of domains with experienced decline. Covariate-adjusted linear regression analyses were used to test whether these SCD scores predicted abnormality in AD biomarkers.ResultsLower A beta-42 levels were associated with a reported decline in memory and language abilities, and with the following SCD-plus features: onset of subjective decline within 5years, confirmation of cognitive decline by an informant, and decline-related worries. Furthermore, both quantitative SCD scores were associated with lower A beta 42 and lower A beta 42/Tau ratio, but not with total Tau or p-Tau181.ConclusionsFindings support the usefulness of a criterion-based interview approach to assess and quantify SCD in the context of AD and validate the current SCD-plus features as predictors of AD pathology. While some features seem to be more closely associated with AD biomarkers than others, aggregated scores over several SCD-plus features or SCD domains may be the best predictors of AD pathology