The influence of depressive symptomatology on episodic memory functioning among clinically nondepressed older adults

Discrepancy between objective and subjective cognition and its association with the trajectory of symptoms and functioning in depressive patients

BACKGROUND

Discrepancy between objective and subjective cognitive deficit is common among patients with major depressive disorders (MDDs) and may play a key role in the mechanism linking cognition with recovery of symptom and psychosocial function. This study, therefore, explores the cognitive discrepancy, and its association with the trajectory of symptoms and functioning over a 6-month period.

METHODS

We used data from the Prospective Research Observation to Assess Cognition in Treated patients with MDD (PROACT) study, from which 598 patients were included. Cognitive discrepancy scores were computed using a novel methodology, with positive values indicating more subjective than objective deficit (i.e. 'underestimation') and negative values indicating more objective than subjective difficulties (i.e. 'overestimation'). Linear growth curve models were employed to examine the association of the cognitive discrepancy with the trajectory of depressive symptoms, psychosocial function, and quality of life.

RESULTS

About 68% of patients displayed disproportionately more objective than subjective cognitive deficit at baseline, and the mean cognitive discrepancy score was -1.4 (2.7). Overestimation was associated with a faster decrease of HDRS-17 (β = -0.46, p = 0.002) and a faster decrease of psychosocial function in social life (β = -0.13, p = 0.013) and family life (β = -0.12, p = 0.026), and a greater improvement of EQ-5D utility score (β = 0.01, p < 0.001).

CONCLUSION

We found a lower sensitivity of cognitive deficit at baseline and its decrease was associated with better health outcomes. Our findings have clinical implications of the necessity to assess both subjective and objective cognition for identification and categorization and to incorporate cognitive and psychological therapies for optimized treatment outcomes.

Machine learning-based prediction of longitudinal cognitive decline in early Parkinson's disease using multimodal features

Patients with Parkinson's Disease (PD) often suffer from cognitive decline. Accurate prediction of cognitive decline is essential for early treatment of at-risk patients. The aim of this study was to develop and evaluate a multimodal machine learning model for the prediction of continuous cognitive decline in patients with early PD. We included 213 PD patients from the Parkinson's Progression Markers Initiative (PPMI) database. Machine learning was used to predict change in Montreal Cognitive Assessment (MoCA) score using the difference between baseline and 4-years follow-up data as outcome. Input features were categorized into four sets: clinical test scores, cerebrospinal fluid (CSF) biomarkers, brain volumes, and genetic variants. All combinations of input feature sets were added to a basic model, which consisted of demographics and baseline cognition. An iterative scheme using RReliefF-based feature ranking and support vector regression in combination with tenfold cross validation was used to determine the optimal number of predictive features and to evaluate model performance for each combination of input feature sets. Our best performing model consisted of a combination of the basic model, clinical test scores and CSF-based biomarkers. This model had 12 features, which included baseline cognition, CSF phosphorylated tau, CSF total tau, CSF amyloid-beta1-42, geriatric depression scale (GDS) scores, and anxiety scores. Interestingly, many of the predictive features in our model have previously been associated with Alzheimer's disease, showing the importance of assessing Alzheimer's disease pathology in patients with Parkinson's disease.

Predictors of Incident Mild Cognitive Impairment and Its Course in a Diverse Community-Based Population

BACKGROUND AND OBJECTIVES

To investigate sociodemographic and medical predictors of incident mild cognitive impairment (MCI) and subsequent course of MCI at follow-up, including sustained MCI diagnosis, classification as cognitively normal, and progression to dementia.

METHODS

Within a community-based cohort, diagnoses of MCI were made with a published algorithm. Diagnosis of dementia was based on clinical consensus. Cox regressions estimated hazard ratios of incident MCI associated with several predictors. Modified Poisson regressions estimated relative risks associated with predictors of diagnostic status at follow-up after incidence.

RESULTS

Among 2,903 cognitively normal participants at baseline, 752 developed MCI over an average of 6.3 (SD 4.5) years (incidence rate 56 per 1,000 person-years). Presence of APOE ε4 and higher medical burden increased risk of incident MCI, while more years of education, more leisure activities, and higher income decreased this risk. Of the incident MCI cases, after an average of 2.4 years of follow-up, 12.9% progressed to dementia, 9.6% declined in functioning and did not meet the algorithmic criteria for MCI but did not meet the clinical criteria for dementia, 29.6% continued to meet MCI criteria, and 47.9% no longer met MCI criteria. Multidomain MCI, presence of APOE ε4, depressive symptoms, and antidepressant use increased the risk of progression to dementia.

DISCUSSION

This community-based study showed that almost half of the individuals with incident MCI diagnoses were classified as cognitively normal at follow-up. Predictors of incident MCI demonstrably differed from those of subsequent MCI course; these findings can refine expectations for cognitive and functional course of those presenting with MCI.

Stress Is Associated With Neurocognitive Function in Hispanic/Latino Adults: Results From HCHS/SOL Socio-Cultural Ancillary Study

OBJECTIVES

The purpose of this study was to evaluate the hypothesis that chronic and acculturative stress would be negatively associated with neurocognitive function among middle aged to older Hispanics/Latinos.

METHOD

Our analytic sample consisted of 3,265 participants (mean age = 56.7 (±0.24)) from the Hispanic Community Health Study/Study of Latinos who participated in its Sociocultural Ancillary Study. During the baseline phase of this project, participants were assessed on multiple domains of neurocognitive function, and completed self-report measures of chronic and acculturative stress.

RESULTS

Each standard deviation increase in chronic stress was associated with lower performance in a verbal learning task (B = -.17, 95% CI [-.32, -.01]); this association was no longer significant after adjusting for mental and physical health symptoms, including depression and anxiety symptoms, and cardiovascular health. A standard deviation increase in acculturative stress was associated with poorer performance in all cognitive measures (Bs range = -.13 to -1.03). Associations of acculturation stress with psychomotor speed, verbal learning, and word fluency remained significant after adjusting for mental and physical health symptoms.

DISCUSSION

Our results suggest that mental and physical health may help explain some cross-sectional associations between stress and cognition and highlight the need to examine culture-specific psychosocial stressors to better understand the context of psychosocial risk factors for neurocognitive performance.

Sertraline and Mirtazapine Versus Placebo in Subgroups of Depression in Dementia: Findings From the HTA-SADD Randomized Controlled Trial

OBJECTIVE

Studies have shown that antidepressants are no better than placebo in treating depression in dementia. The authors examined antidepressant efficacy in subgroups of depression in dementia with different depressive symptom profiles.

METHODS

This study focuses on exploratory secondary analyses on the randomized, parallel-group, double-blind, placebo-controlled Health Technology Assessment Study of the Use of Antidepressants for Depression in Dementia (HTA-SADD) trial. The setting included old-age psychiatry services in nine centers in England. The participants included 326 patients meeting National Institute of Neurological and Communicative Disorders and Stroke/Alzheimer's Disease and Related Disorders Association probable/possible Alzheimer disease criteria, and Cornell Scale for Depression in Dementia (CSDD) scores of 8 or more. Intervention was placebo (n = 111), sertraline (n = 107), or mirtazapine (n = 108). Latent class analyses (LCA) on baseline CSDD items clustered participants into symptom-based subgroups. Mixed-model analysis evaluated CSDD improvement at 13 and 39 weeks by randomization in each subgroup.

RESULTS

LCA yielded 4 subgroups: severe (n = 34), psychological (n = 86), affective (n = 129), and somatic (n = 77). Mirtazapine, but not sertraline, outperformed placebo in the psychological subgroup at week 13 (adjusted estimate: -2.77 [standard error (SE) 1.16; 95% confidence interval: -5.09 to -0.46]), which remained, but lost statistical significance at week 39 (adjusted estimate: -2.97 [SE 1.59; 95% confidence interval: -6.15 to 0.20]). Neither sertraline nor mirtazapine outperformed placebo in the other subgroups.

CONCLUSION

Because of the exploratory nature of the analyses and the small sample sizes for subgroup analysis there is the need for caution in interpreting these data. Replication of the potential effects of mirtazapine in the subgroup of those with depression in dementia with "psychological" symptoms would be valuable. These data should not change clinical practice, but future trials should consider stratifying types of depression in dementia in secondary analyses.

Anhedonia and Dysphoria Are Differentially Associated with the Risk of Dementia in the Cognitively Normal Elderly Individuals: A Prospective Cohort Study

OBJECTIVE

We investigated the impact of depressed mood (dysphoria) and loss of interest or pleasure (anhedonia)on the risk of dementia in cognitively-normal elderly individuals.

METHODS

This study included 2,685 cognitively-normal elderly individuals who completed the baseline and 4-year follow-up assessments of the Korean Longitudinal Study on Cognitive Aging and Dementia. We ascertained the presence of dysphoria and anhedonia using the Mini International Neuropsychiatric Inventory. We defined subjective cognitive decline as the presence of subjective cognitive complaints without objective cognitive impairments. We analyzed the association of dysphoria and anhedonia with the risk of cognitive disorders using multinomial logistic regression analysis adjusted for age, sex, education, Cumulative Illness Rating Scale score, Apolipoprotein E genotype, and neuropsychological test performance.

RESULTS

During the 4-year follow-up period, anhedonia was associated with an approximately twofold higher risk of mild cognitive impairment (OR=2.09, 95% CI=1.20-3.64, p=0.008) and fivefold higher risk of dementia (OR=5.07, 95% CI=1.44-17.92, p=0.012) but was not associated with the risk of subjective cognitive decline. In contrast, dysphoria was associated with an approximately twofold higher risk of subjective cognitive decline (OR=2.06, 95% CI=1.33-3.19, p=0.001) and 1.7-fold higher risk of mild cognitive impairment (OR=1.75, 95% CI=1.00-3.05, p=0.048) but was not associated with the risk of dementia.

CONCLUSION

Anhedonia, but not dysphoria, is a risk factor of dementia in cognitively-normal elderly individuals.

Associations between subclinical depressive symptoms and reduced brain volume in middle-aged to older adults

OBJECTIVES

The associations between subclinical depressive symptoms, as well specific symptom subscales, on brain structure in aging are not completely elucidated. This study investigated the extent to which depressive symptoms were related to brain volumes in fronto-limbic structures in a sample of middle-aged to older adults.

METHOD

Eighty participants underwent structural neuroimaging and completed the Beck Depression Inventory, 2nd Edition (BDI-II), which comprises separate affective, cognitive, and somatic subscales. Gray matter volumes were extracted from the caudal and rostral anterior cingulate, posterior cingulate, hippocampus, and amygdala. Hierarchical regression models examined the relationship between brain volumes and (i) total depressive symptoms and (ii) BDI-II subscales were conducted.

RESULTS

After adjusting for total intracranial volume, race, and age, higher total depressive symptoms were associated with smaller hippocampal volume (p = 0.005). For the symptom subscales, after controlling for the abovementioned covariates and the influence of the other symptom subscales, more somatic symptoms were related to smaller posterior cingulate (p = 0.025) and hippocampal (p < 0.001) volumes. In contrast, the affective and cognitive subscales were not associated with brain volumes in any regions of interest.

CONCLUSION

Our data showed that greater symptomatology was associated with smaller volume in limbic brain regions. These findings provide evidence for preclinical biological markers of major depression and specifically advance knowledge of the relationship between subclinical depressive symptoms and brain volume. Importantly, we observed variations by specific depressive symptom subscales, suggesting a symptom-differential relationship between subclinical depression and brain volume alterations in middle-aged and older individuals.

Is episodic memory performance more vulnerable to depressive affect in older adulthood?

This study examined how age, depressive symptoms, demographic variables, frailty, and health factors jointly influence episodic memory across the lifespan in two large, diverse samples. Hierarchical regression analyses from both samples showed that depressive symptoms negatively impacted episodic memory performance with the effect being more pronounced for older adults. Health and frailty tended not to be associated with episodic memory. However, the main effect of depressive symptoms tended to remain significant over and above other predictors, while the interaction with age was weakened with the addition of demographic variables. The unique contribution of this study is demonstrating that the relationship between depressive symptoms and episodic memory is moderated by age across relatively large non-clinical lifespan samples of adults. The findings indicate the importance of measuring and studying depressive symptoms during the course of aging in order to better understand the complex relationship between age, affect, physical functioning, and memory.

Symptom Dimensions of Depression and 3-Year Incidence of Dementia: Results From the Amsterdam Study of the Elderly

OBJECTIVE

To evaluate the association between depressive symptom dimensions and incident dementia in a community sample of older persons.

METHODS

Depressive symptoms at baseline and incident dementia at 3-year follow-up were assessed with the Geriatric Mental State (GMS)-Automated Geriatric Examination for Computer Assisted Taxonomy in nondemented persons aged 65 years or older. Exploratory and confirmatory bifactor analysis on the depression items yielded a general depression factor characterized by all GMS items and a cognitive/motivational factor characterized by cognitive and motivational "depressive" symptoms and the absence of depressed mood.

RESULTS

Ninety-three of 1911 persons had developed dementia at follow-up. The general depression factor increased the risk of dementia after adjustment for covariates (odds ratio [OR]: 1.48, 95% confidence interval [CI]: 1.14-1.92), but the cognitive/motivational factor did not (OR: 1.05, 95% CI: 0.75-1.47). However, in 1725 nondepressed older persons, the cognitive/motivational factor significantly predicted dementia after adjustment for covariates (OR: 1.53, 95% CI: 1.03-2.28) but not anymore after additional adjustment for subjective memory complaints (OR: 1.41, 95% CI: 0.94-2.13). The general depression factor did not significantly predict dementia in nondepressed older persons (OR: 1.15, 95% CI: 0.80-1.66).

CONCLUSION

Our findings suggest that the increased risk of dementia associated with depressive symptoms in many previous studies appears to be heterogeneous, that is, it is likely due to different underlying pathways, including a pathway involving depression itself and a pathway in which cognitive and motivational symptoms reflect subjective cognitive complaints, particularly in the absence of depressed mood. These different pathways might warrant a different treatment approach.

Interactive effects of KIBRA and CLSTN2 polymorphisms on episodic memory in old-age unipolar depression

The KIBRA (rs17070145) C-allele and the CLSTN2 (rs6439886) T-allele have both been associated with poorer episodic memory performance. Given that episodic memory is affected in depression, we hypothesized that the combination of these risk alleles would be particularly detrimental to episodic memory performance in depressed persons. In the population-based SNAC-K study, 2170 participants (≥ 60 years) without dementia (DSM-IV criteria) and antidepressant pharmacotherapy were clinically examined and diagnosed following ICD-10 criteria for unipolar depression, and genotyped for KIBRA and CLSTN2. Participants were categorized according to unipolar depression status (yes, no) and genotype combinations (KIBRA: CC, any T; CLSTN2: TT, any C). Critically, a three-way interaction effect showed that the CC/TT genotype combination was associated with poorer episodic recall and recognition performance only in depressed elderly persons, with depressed CC/TT carriers consistently performing at the lowest level. This finding supports the view that effects of genetic polymorphisms on cognitive functioning may be most easily disclosed at suboptimal levels of cognitive ability, such as in old-age depression.

Does self-reported sleep quality predict poor cognitive performance among elderly living in elderly homes?

OBJECTIVES

Sleep complaints are common among elderly, especially institutionalized elderly, as they experience poorer sleep quality and higher use of sedative hypnotics, when compared to community-dwelling elderly. Recent findings suggest that there may be a relationship between poor quality of sleep and cognitive deficits. This study aimed at studying the relation between sleep quality and cognitive performance in older adults living in elderly homes.

METHOD

100 elderly living in an elderly home in El Mansoura, Egypt, were recruited in this study, 50 cases with subjective poor quality of sleep and 50 controls with subjective good quality of sleep as assessed by Pittsburgh sleep quality index (PSQI). Each participant went through comprehensive geriatric assessment (CGA), including geriatric depression scale (GDS), assessment of cognitive function by mini mental state examination (MMSE).

RESULTS

52% of poor sleepers showed impaired MMSE, while only 24% of good sleepers had impaired MMSE. Both orientation and (attention and calculation) were more affected (P = 0.027 and 0.035, respectively). Linear correlation coefficient between PSQI and different variables revealed significant negative correlation with total MMSE score, attention and calculation.

CONCLUSION

Poor quality of sleep is related to cognitive impairment among elderly living in elderly homes and this problem should be taken in consideration among this group of elders.

Cognitive deficits in unipolar old-age depression: a population-based study

BACKGROUND

There is substantial variability in the degree of cognitive impairment among older depressed persons. Inconsistencies in previous findings may be due to differences in clinical and demographic characteristics across study samples. We assessed the influence of unipolar depression and severity of depression on cognitive performance in a population-based sample of elderly persons aged ⩾60 years.

METHOD

Eighty-nine persons fulfilled ICD-10 criteria for unipolar depression (mild, n = 48; moderate, n = 38; severe, n = 3) after thorough screening for dementia (DSM-IV criteria), psychiatric co-morbidities and antidepressant pharmacotherapy. Participants (n = 2486) were administered an extensive cognitive test battery.

RESULTS

Moderate/severe unipolar depression was associated with poorer performance on tasks assessing processing speed, attention, executive function, verbal fluency, episodic memory and vocabulary. Mild depression was associated with poorer performance in processing speed, and few differences between mild and moderate/severe depression were observed. No association between depression and short-term memory, general knowledge or spatial ability was observed. Increasing age did not exacerbate the depression-related cognitive deficits, and the deficits remained largely unchanged after excluding persons in a preclinical phase of dementia. Furthermore, depression-related cognitive deficits were not associated with other pharmacological treatments that may affect cognitive performance.

CONCLUSIONS

Cognitive deficits in unipolar old-age depression involve a range of domains and the cognitive deficits seem to follow the spectrum of depression severity. The finding that mild depression was also associated with poorer cognitive functioning underscores the importance of detecting mild depression in elderly persons.

Intrusive Thoughts Mediate the Association between Neuroticism and Cognitive Function

Although research has established a negative association between trait neuroticism and cognition, little is known about the mechanisms that underlie this relationship. We examined the tendency to experience intrusive thoughts and negative affect as potential mediators of the relationship between neuroticism and cognitive performance. We hypothesized that the tendency to experience intrusive thoughts reflects ineffective attentional control and would account for the relationship between neuroticism and cognitive performance over and above the mediating effect of negative affect. Three hundred seventeen adults (M_age =49.43) completed a series of attention-demanding cognitive tasks as well as self-report measures of intrusive thoughts, negative affect, and neuroticism. Intrusive thoughts mediated the association between trait neuroticism and cognitive performance beyond negative affect. These findings are consistent with the hypothesis that the tendency to experience intrusive thoughts is a mechanism through which trait neuroticism influences cognitive performance.

Thyroid stimulating hormone and prospective memory functioning in old age

Alterations of thyroid functioning are common in old age. Even among persons free from thyroid disorders, subclinical variations in thyroid functioning may affect cognitive performance. However, it is unknown whether prospective memory (ProM) is related to thyroid stimulating hormone (TSH) variations. An association could be expected, as changes in the thyroid gland have been linked to alterations in frontal brain regions that play a key role in prospective remembering. Thus, the aim of this study was to examine whether subclinical variations in thyroid functioning affect ProM performance. We studied 103 participants, 75 years and older, who were free from thyroid disorders and had serum levels of TSH and thyroxine (T4) within normal ranges. Interestingly, we found a non-linear association between TSH and ProM performance, where persons with TSH levels above the fourth quartile performed substantially better than persons in the other quartiles. T4 levels were unrelated to ProM performance. This pattern suggests that the previously identified "normal-range" interval for TSH should be moved further up in old age, at least when cognitive functioning is considered.

The association of anxiety and depressive symptoms with cognitive performance in community-dwelling older adults

The authors examined the association of anxiety, depressive symptoms, and their co-occurrence on cognitive processes in 102 community-dwelling older adults. Participants completed anxiety and depression questionnaires as well as measures of episodic and semantic memory, word fluency, processing speed/shifting attention, and inhibition. Participants with only increased anxiety had poorer processing speed/shifting attention and inhibition, but depressive symptoms alone were not associated with any cognitive deficits. Although coexisting anxiety and depressive symptoms were associated with deficits in 3 cognitive domains, reductions in inhibition were solely attributed to anxiety. Findings suggest an excess cognitive load on inhibitory ability in normal older adults reporting mild anxiety.

Self-reported sleep quality predicts poor cognitive performance in healthy older adults

This study examined the relation between sleep quality and cognitive performance in older adults, controlling for common medical comorbidities. Participants were community volunteers who, while not selected on the basis of their sleep, did report substantial variability in sleep quality. Good and poor sleepers differed on tests of working memory, attentional set shifting, and abstract problem solving but not on processing speed, inhibitory function, or episodic memory. Poor sleep was also associated with increased depressive symptomatology but only for functional symptoms (e.g., decreased concentration) and not for mood (e.g., sadness). The relationships between sleep quality and cognition were not explained by confound factors such as cerebrovascular disease, depression, or medication usage. Sleep problems may contribute to performance variability between elderly individuals but only in certain cognitive domains.

Differential effects of depressive symptoms on prospective and retrospective memory in old age

The effects of depressive symptoms on prospective and retrospective memory were examined in a population-based sample of elderly persons (n = 404). Depression was assessed using the Comprehensive Psychopathological Rating Scale and treated as a continuous variable. The variation in depressive symptoms ranged from no symptoms to presence of a clinical depression. Depressive symptoms had a negative effect on consolidation and retrieval in retrospective memory. However, the retrospective, but not the prospective, component of prospective memory was affected by depression. The findings are discussed in light of medial-temporal lobe alterations in depression.

Cognitive deficits in preclinical Alzheimer's disease and vascular dementia: Patterns of findings from the Kungsholmen Project

Using data from the Kungsholmen Project (KP), we describe a program of research that focuses on preclinical cognitive markers of dementia. A large number of KP studies convincingly demonstrate that there is a preclinical period that spans several years in both Alzheimer's disease (AD) and vascular dementia (VaD), during which cognitive deficits are possible to detect. In AD, the preclinical impairment generalizes across a variety of cognitive domains, including episodic memory, executive functioning, perceptual speed, attention, verbal ability, and visuospatial skill. Although less research has been directed at cognition in preclinical VaD, the emerging evidence suggests a rather broad prodromal impairment in this disease as well. Thus, the nature of the cognitive impairment appears to be largely similar in preclinical AD and VaD. Despite the fact that average group differences in cognitive performance between incident dementia cases and controls are large several years before diagnosis, the distribution of scores in these groups overlap greatly. In order to improve group classification, future research should consider combining cognitive markers with preclinical indicators from other domains (e.g., biological, clinical, social, genetic) into multivariate prediction models.

Diabetes mellitus and dementia

Alzheimer's disease (AD) and diabetes mellitus (DM) are two of the most common and devastating health problems in the elderly. They share a number of common features amongst which high prevalence after 65 years, important impact of patient's quality of life, substantial health care costs. Reviews on the epidemiological studies on cognitive impairment in patients with DM found evidence of cross-sectional and prospective associations between type 2 DM and moderate cognitive impairment, on memory and executive functions. There is also evidence for an elevated risk of both vascular dementia and AD in patients with type 2 DM, albeit with strong interaction of other factors such as hypertension, dyslipidaemia and ApoE genotype. DM is an independent predictor of post-stroke dementia. DM being an atherogenic risk factor, it may increase the risk of dementia through associations with stroke, causing vascular dementia. In addition, vascular reactivity may be adversely affected by advanced glycosylation end products resulting in more subtle perfusion abnormalities. Cerebrovascular disease may exacerbate AD through direct interactions between the two pathological processes or through cognitive impairment secondary to cerebrovascular disease "unmasking" AD at an earlier stage than it would otherwise become apparent. The increased risk of AD may also be mediated by the exacerbation of B-amyloid neurotoxicity by advanced glycosylation end products identified in the matrix of neurofibrillary tangles and amyloid plaques in AD brains, or associations with insulin functions. Decreased cholinergic transport across the blood-brain barrier observed in diabetic animals may exacerbate cognitive impairment in AD. Many interventions could reduce the cognitive decline associated with DM, yet not enough are taken into account so far.

Positive affect and its relationship to free recall memory performance in a sample of older Dutch adults from the Maastricht Aging Study

OBJECTIVE

A Dutch translation of the Positive and Negative Affect Scale (PANAS) was used to measure Positive Affect (PA) and its relationship to episodic memory in a sample of Dutch adults between the ages of 40 to 82 years. Specifically, the role of PA was examined as a predictor of performance on a serial list learning task that included a recognition and free recall component.

METHODS

Participants were divided into two age groupings representing middle-age (40 to 64 years) and older (65 to 82 years) adults with respect to the study sample.

RESULTS

PA was not related to recognition performance in either age grouping. In the older age group, however, PA predicted free recall.

CONCLUSIONS

PA facilitated episodic memory in older adults when unsupported tasks conditions were present that placed heavy demands on processing resources.

Negligible effects of depression on verbal and spatial performance in Alzheimer's disease

We examined whether a diagnosis of depression affects verbal and visuospatial performance in Alzheimer's disease (AD). Using data from a population-based study, persons with AD and depression (AD/D), AD alone and a control group of normal older adults were compared in two tests of verbal ability (category and letter fluency) and two tests of visuospatial skill (block design and clock drawing). As expected, there were clear AD-related deficits across all cognitive tasks. More importantly, the AD and AD/D groups were indistinguishable on all task variables. The lack of effects of depression was discussed relative to the view that those symptoms of this disease which are especially detrimental to cognitive functioning (e.g. concentration difficulties, lack of interest, loss of energy) may already be present in AD as a result of the neurodegenerative process.

Longitudinal follow-up of depressive symptoms among normal versus cognitively impaired elderly

OBJECTIVES

This prospectively designed longitudinal study assesses prevalence, incidence and prognosis of depressive symptoms among cognitively normal elderly volunteers compared with patients with mild cognitive impairment (MCI), dementia of Alzheimer type (DAT), and vascular dementia (VAD). Possible relationships between depressive symptoms, cognitive performance, disease types, and effects of antidepressant treatment were analyzed.

METHODS

Two hundred and ninety four subjects exhibiting different levels of cognitive performance were admitted to this study. Demographics, cardiovascular and neurodegenerative risk factors, together with measures of neuropsychological test performance, were obtained at sequential visits. Depressive symptoms were selectively treated with antidepressant medications.

RESULTS

One hundred and forty six subjects with normal cognition, 19 subjects with MCI, 42 patients with DAT, and 32 patients with VAD were followed for a mean of 3.5 years. With the passage of time, there were trends showing prevalence of depressive symptoms to decrease among DAT and to increase among VAD patients. VAD patients exhibited the highest incidences of new-onset depressive symptoms, followed in incidence by DAT and MCI groups. Depressive symptoms among VAD and MCI patients were more persistent and refractory to antidepressant medications than for DAT patients. Trends suggested that antidepressant treatment might benefit MCI and VAD subjects more than DAT patients. Motivationally related depressive symptoms accounted for major components of elevated Hamilton depression rating scale scores.

CONCLUSIONS

Depressive symptoms among DAT patients have higher rates of spontaneous resolution, without requiring intensive drug treatment, than among VAD patients in whom depressive symptoms are more persistent and refractory to drug treatment. Early depressive symptoms among subjects with MCI may represent a preclinical sign and should be considered as a risk factor for impending DAT or VAD among the elderly.

Responses of different cell lines from ocular tissues to elevated hydrostatic pressure

BACKGROUND/AIMS

Mechanical forces are thought to induce cellular responses through activation of signalling pathways. Cells within the intraocular environment are exposed to constant changes in the levels of intraocular pressure. In this study, an attempt was made to determine the acute effects of elevated hydrostatic pressure on different intraocular cells grown in culture.

METHODS

Different cell lines derived from ocular tissues including non-pigmented and pigmented ciliary epithelium, trabecular meshwork, retina, and lamina cribrosa were incubated in a pressurised chamber at 50 mm Hg in a culture incubator at 37 degrees C for up to 6 hours. Control cells were incubated at atmospheric pressure. The viability of the cells was examined using their intracellular esterase activity. The morphology and cytoskeleton of the cells were investigated using microscopy and phalloidin staining. Adenylyl cyclase activity was assessed by measuring the conversion of [(3)H]-cAMP from [(3)H]-ATP in response to elevated hydrostatic pressure for 1-6 hours. In addition, at the end of incubation period under elevated hydrostatic pressure the recovery of adenylyl cyclase activity to control levels was examined.

RESULTS

Cell viability did not change following exposure to elevated hydrostatic pressure for 6 hours. Cells subjected to elevated hydrostatic pressure demonstrated morphological differences characterised by a more rounded shape and a redistribution of actin stress fibres that was most prominent in lamina cribrosa astrocytes. A time dependent increase in basal adenylyl cyclase activity, and a decrease in maximum forskolin stimulated activity were observed in all cell lines following exposure to elevated hydrostatic pressure.

CONCLUSION

These observations demonstrate that cell lines from different ocular tissues are sensitive to changes in external pressure in vitro. They exhibit morphological and cytoskeletal changes as well as significant alterations of intracellular adenylyl cyclase activity following exposure to acute and sustained levels of elevated hydrostatic pressure of up to 6 hours' duration.

Zehn-Wort-Merkliste mit Imaginations-Einspeicherhilfe

Zusammenfassung: Die klinische Erfassung von Gedächtnisstörungen erfolgt in der Regel über die Vorgabe von drei Merkwörtern. Derzeit existieren keine besseren Verfahren, die auch klinisch im Sinne eines «bedside testing» einzusetzen sind. Mit der Zehn-Wort-Merkliste wird ein für die klinische Praxis konzipiertes Verfahren vorgestellt, das die Mängel tradierter klinischer Untersuchungsansätze zur Erfassung von episodischen Gedächtnisleistungen überwinden hilft. Die Aufgabe, sich die Wörter zu merken, wird verbunden mit der Aufforderung, sich den vom Wort abgebildeten Begriff vorzustellen und mit einem tatsächlich vorhandenen Gegenstand (z. B. einem Tisch) hinsichtlich seiner Größe zu vergleichen. Durch dieses Vorgehen wird erreicht, daß für die Merkwörter bildliche Vorstellungen generiert und zugleich mögliche Reverberationen unterbunden werden. Eine im Rahmen einer Gedächtnisambulanz durchgeführte Studie unterstreicht die - im Vergleich mit anderen Untersuchungsverfahren - hohe diskriminative Bedeutung der Zehn-Wort-Merkliste bei der Trennung dreier Diagnosegruppen (Demenz, leichte kognitive Störung, funktionell gestörte, vorwiegend depressive Patienten) und Personen ohne psychiatrische Diagnose (Wilks'λ = 0.34). Die konkurrente Validität (rtc = 0.75) des Verfahrens is hoch. Es werden erste Ergebnisse aus Untersuchungen an gesunden Personen mit Hinweisen auf die Stabilität (rtt = 0.84, rtt = 0.86) der Zehn-Wort-Merkliste berichtet.

The influence of prolactin response to d-fenfluramine on executive functioning in major depression

BACKGROUND

The main purpose of this study was to assess the influence of serotonergic activity, as measured by prolactin response to d-fenfluramine, on executive functioning in major depression.

METHODS

Forty-one persons between 22 and 71 years of age who met the DSM-IV criteria for major depressive episode were administered the Wisconsin Card Sorting Test (WCST) in computerized format, and d-fenfluramine was administered orally. Postfenfluramine blood samples for ascertaining plasma prolactin levels were obtained.

RESULTS

The key finding was that prolactin response was positively related to four out of five selected WCST variables. Also, increasing age was associated with decreasing WCST performance. There was no interaction between prolactin response and age, indicating that the effects of prolactin response on the WCST generalized across the age range examined.

CONCLUSIONS

The overall pattern of results suggests that there may be a relationship between serotonergic activity and executive functioning in major depression.

Memory and metamemory functioning among depressed patients

Memory and metamemory functioning were studied among 30 adult patients suffering from major depression. The results indicate that, besides showing signs of cognitive slowing, the patients were especially vulnerable to visual memory impairment, whereas verbal, short-term memory, and recall by recognition were more often unaffected. The patients whose depression was characterized by physiological symptoms, such as loss of appetite and sleep disturbances, showed impairment in traditional short-term memory measures, whereas there was no firm connection between cognitive or behavioral depressive symptoms and memory functioning. The depressive patients' generalized view of their memory capability was strongly underestimated, whereas online metamemory accuracy by which one perceives and makes inferences about one's performance was adequate.

Type 2 diabetes mellitus, cognitive impairment and dementia

AIMS

We set out to examine the evidence for an association between cognitive impairment or dementia and the presence of Type 2 diabetes mellitus (DM). We also sought evidence of potential mechanisms for such an association.

METHODS

A literature search of three databases was performed and the reference lists of the papers so identified were examined, using English language papers only.

RESULTS

We found evidence of cross-sectional and prospective associations between Type 2 DM and cognitive impairment, probably both for memory and executive function. There is also evidence for an elevated risk of both vascular dementia and Alzheimer's disease in Type 2 DM albeit with strong interaction of other factors such as hypertension, dyslipidaemia and apolipoprotein E phenotype. Both vascular and non-vascular factors are likely to play a role in dementia in diabetes.

CONCLUSIONS

Current classification structures for dementia may not be adequate in diabetes, where mixed pathogenesis is likely. Further research into the mechanisms of cognitive impairment in Type 2 DM may allow us to challenge the concept of dementia, at least in these patients, as an irremediable disease.

Executive deficits in major depression

Clinically depressed patients and control subjects were examined by means of different tests to assess executive functions (the Wisconsin Card Sorting Test, the Stroop Color Word Test and a test of verbal fluency). The results indicate that the depressed patients were generally slower than the controls, as reflected by longer retrieval times for both words and colours. Furthermore, the depressed patients showed impairment with regard to altering behaviour appropriately in response to feedback. However, there were no depression-related increases in perseverative responses, and the ability to inhibit irrelevant information was unaffected by depression. No relationship was found between specific depressive symptoms or the severity of depression and cognitive performance. The overall pattern of results suggests that depression may affect various executive functions in a differentiated manner.