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Systematic Reviews Dec 2017Social relationships, which are contingent on access to social networks, promote engagement in social activities and provide access to social support. These social... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Social relationships, which are contingent on access to social networks, promote engagement in social activities and provide access to social support. These social factors have been shown to positively impact health outcomes. In the current systematic review, we offer a comprehensive overview of the impact of social activities, social networks and social support on the cognitive functioning of healthy older adults (50+) and examine the differential effects of aspects of social relationships on various cognitive domains.
METHODS
We followed PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) guidelines, and collated data from randomised controlled trials (RCTs), genetic and observational studies. Independent variables of interest included subjective measures of social activities, social networks, and social support, and composite measures of social relationships (CMSR). The primary outcome of interest was cognitive function divided into domains of episodic memory, semantic memory, overall memory ability, working memory, verbal fluency, reasoning, attention, processing speed, visuospatial abilities, overall executive functioning and global cognition.
RESULTS
Thirty-nine studies were included in the review; three RCTs, 34 observational studies, and two genetic studies. Evidence suggests a relationship between (1) social activity and global cognition and overall executive functioning, working memory, visuospatial abilities and processing speed but not episodic memory, verbal fluency, reasoning or attention; (2) social networks and global cognition but not episodic memory, attention or processing speed; (3) social support and global cognition and episodic memory but not attention or processing speed; and (4) CMSR and episodic memory and verbal fluency but not global cognition.
CONCLUSIONS
The results support prior conclusions that there is an association between social relationships and cognitive function but the exact nature of this association remains unclear. Implications of the findings are discussed and suggestions for future research provided.
SYSTEMATIC REVIEW REGISTRATION
PROSPERO 2012: CRD42012003248 .
Topics: Cognition; Executive Function; Humans; Interpersonal Relations; Memory; Social Participation; Social Support
PubMed: 29258596
DOI: 10.1186/s13643-017-0632-2 -
Journal of Alzheimer's Disease : JAD 2023Semantic and Phonological fluency (SF and PF) are routinely evaluated in patients with Alzheimer's disease (AD). There are disagreements in the literature regarding... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Semantic and Phonological fluency (SF and PF) are routinely evaluated in patients with Alzheimer's disease (AD). There are disagreements in the literature regarding which fluency task is more affected while developing AD. Most studies focus on SF assessment, given its connection with the temporoparietal amnesic system. PF is less reported, it is related to working memory, which is also impaired in probable and diagnosed AD. Differentiating between performance on these tasks might be informative in early AD diagnosis, providing an accurate linguistic profile.
OBJECTIVE
Compare SF and PF performance in healthy volunteers, volunteers with probable AD, and patients with AD diagnosis, considering the heterogeneity of age, gender, and educational level variables.
METHODS
A total of 8 studies were included for meta-analysis, reaching a sample size of 1,270 individuals (568 patients diagnosed with AD, 340 with probable AD diagnosis, and 362 healthy volunteers).
RESULTS
The three groups consistently performed better on SF than PF. When progressing to a diagnosis of AD, we observed a significant difference in SF and PF performance across our 3 groups of interest (p = 0.04). The age variable explained a proportion of this difference in task performance across the groups, and as age increases, both tasks equally worsen.
CONCLUSION
The performance of SF and PF might play a differential role in early AD diagnosis. These tasks rely on partially different neural bases of language processing. They are thus worth exploring independently in diagnosing normal aging and its transition to pathological stages, including probable and diagnosed AD.
Topics: Humans; Semantics; Alzheimer Disease; Verbal Behavior; Neuropsychological Tests; Linguistics
PubMed: 37482994
DOI: 10.3233/JAD-221272 -
European Journal of Ageing Aug 2023The cognitive complaints encountered in late-life depression (LLD) make it difficult to distinguish from amnestic mild cognitive impairment (aMCI) and Alzheimer's... (Review)
Review
The role of semantic assessment in the differential diagnosis between late-life depression and Alzheimer's disease or amnestic mild cognitive impairment: systematic review and meta-analysis.
OBJECT
The cognitive complaints encountered in late-life depression (LLD) make it difficult to distinguish from amnestic mild cognitive impairment (aMCI) and Alzheimer's disease (AD) based on an analysis of neurocognitive disorders. The hypothesis of the early impairment of semantic memory in AD and aMCI is considered a potential differential cognitive clue, but the absence of this impairment has not yet been confirmed in LLD.
METHOD
Based on the PRISMA method, we systematically seek neuropsychological assessments of individuals with LLD, the present study included 31 studies representing 3291 controls and 2820 people with LLD. Wherever possible, studies that tested simultaneously groups with LLD, AD (or aMCI) were also included. The results of the group of neuropsychological tasks relying on semantic memory were analyzed in two groups of tasks with high- or low-executive demand. The mean average effect of LLD was calculated and compared to the incremental effect of aMCI or AD on the scores. Linear regressions including education, age, and severity and type of depression were run to seek their power of prediction for the mean average effects.
RESULTS
LLD has a medium effect on scores at semantic and phonemic fluency and naming and a small average effect on the low-executive demand tasks. Differences in education is a predictor of the effect of LLD on phonemic fluency and naming but not on semantic fluency or on low-executive demand tasks. Except for semantic fluency, aMCI did not demonstrate an incremental effect on the scores compared to LLD, while AD did, for all the tasks except phonemic fluency.
CONCLUSION
Assessment of semantic memory can be a discriminating clue for the distinction between depression and Alzheimer's disease but some methodological variables are highly influential to the scores, especially education. However, high-executive semantic tasks alone do not allow us to clearly distinguish LLD from AD or aMCI, as both pathologies seem to have a largely dialectical influential relationship, but low-executive semantic tasks appear as more sensible to this pathological distinction.
PubMed: 37563432
DOI: 10.1007/s10433-023-00780-z -
Cortex; a Journal Devoted To the Study... Nov 2014The amygdala is suggested to serve as a key structure in the emotional brain, implicated in diverse affective processes. Still, the bulk of existing neuroscientific... (Review)
Review
The amygdala is suggested to serve as a key structure in the emotional brain, implicated in diverse affective processes. Still, the bulk of existing neuroscientific investigations of the amygdala relies on conventional neuroimaging techniques such as fMRI, which are very useful but subject to limitations. These limitations are particular to their temporal resolution, but also to their spatial precision at a very fine-grained level. Here, we review studies investigating the functional profile of the human amygdala using intracranial electroencephalography (iEEG), an invasive technique with high temporal and spatial precision. We conducted a systematic literature review of 47 iEEG studies investigating the human amygdala, and we focus on two content-related domains and one process-related domain: (1) memory formation and retrieval; (2) affective processing; and (3) latency components. This review reveals the human amygdala to engage in invariant semantic encoding and recognition of specific objects and individuals, independent of context or visuospatial attributes, and to discriminate between familiar and novel stimuli. The review highlights the amygdala's role in emotion processing witnessed in differential treatment of social-affective facial cues, differential neuronal firing to relevant novel stimuli, and habituation to familiar affective stimuli. Overall, the review suggests the amygdala plays a key role in the processing of affective relevance. Finally, this review delineates effects on amygdala neuronal activity into three time latency windows (post-stimulus onset). The early window (∼ 5 0-290 msec) subsumes effects respective to exogenous stimulus-driven affective processing of faces and emotion. The intermediate window (∼ 270-470 msec) comprises effects related to explicit attention to novel task-relevant stimuli, irrespective of sensory modality. The late window (∼ 600-1400 msec) subsumes effects from tasks soliciting semantic associations and working memory during affective processing. We juxtapose these iEEG data with current clinical topics relevant to amygdala activation and propose avenues for future investigation of the amygdala using iEEG methods.
Topics: Affect; Amygdala; Attention; Electroencephalography; Emotions; Functional Neuroimaging; Humans; Image Processing, Computer-Assisted
PubMed: 25043736
DOI: 10.1016/j.cortex.2014.06.010 -
Pharmacology, Biochemistry, and Behavior Feb 2023Approximately two-thirds of patients with major depressive disorder (MDD) fail to respond to conventional antidepressants, suggesting that additional mechanisms are... (Review)
Review
Approximately two-thirds of patients with major depressive disorder (MDD) fail to respond to conventional antidepressants, suggesting that additional mechanisms are involved in the MDD pathophysiology. In this scenario, the glutamatergic system represents a promising therapeutic target for treatment-resistant depression. To our knowledge, this is the first study using semantic approach with systems biology to identify potential targets involved in the fast-acting antidepressant effects of ketamine and its enantiomers as well as identifying specific targets of (R)-ketamine. We performed a systematic review, followed by a semantic analysis and functional gene enrichment to identify the main biological processes involved in the therapeutic effects of these agents. Protein-protein interaction networks were constructed, and the genes exclusively regulated by (R)-ketamine were explored. We found that the regulation of α-Amino-3-Hydroxy-5-Methyl-4-Isoxazolepropionic Acid (AMPA) receptor and N-methyl-d-aspartate (NMDA) receptor subunits-Postsynaptic Protein 95 (PSD-95), Brain Derived Neurotrophic Factor (BDNF), and Tyrosine Receptor Kinase B (TrkB) are shared by the three-antidepressant agents, reinforcing the central role of the glutamatergic system and neurogenesis on its therapeutic effects. Differential regulation of Transforming Growth Factor Beta 1 (TGF-β1) receptors-Mitogen-Activated Protein Kinases (MAPK's), Receptor Activator of Nuclear Factor-Kappa Beta Ligand (RANKL), and Serotonin Transporter (SERT) seems to be particularly involved in (R)-ketamine antidepressant effects. Our data helps further studies investigating the relationship between these targets and the mechanisms of (R)-ketamine and searching for other therapeutic compounds that share the regulation of these specific biomolecules. Ultimately, this study could contribute to improve the fast management of depressive-like symptoms with less detrimental side effects than ketamine and (S)-ketamine.
Topics: Humans; Ketamine; Depression; Depressive Disorder, Major; Systems Biology; Antidepressive Agents; Receptors, AMPA; Receptors, N-Methyl-D-Aspartate
PubMed: 36731751
DOI: 10.1016/j.pbb.2023.173523 -
European Journal of Ageing Aug 2023
Correction: The role of semantic assessment in the differential diagnosis between late‑life depression and Alzheimer's disease or amnestic mild cognitive impairment: systematic review and meta‑analysis.
PubMed: 37612530
DOI: 10.1007/s10433-023-00783-w -
Sleep Medicine Reviews Apr 2017Fatigue is a frequent and distressing symptom in patients with multiple sclerosis (MS). In contrast, sleepiness, characterized by difficulties to stay awake and alert... (Review)
Review
Fatigue is a frequent and distressing symptom in patients with multiple sclerosis (MS). In contrast, sleepiness, characterized by difficulties to stay awake and alert during the day, seems to be less prevalent in MS; however, exact studies are lacking. In addition, there is a semantic confusion of the concepts of "fatigue" and "sleepiness", which are often used interchangeably. We conducted a systematic review of studies using the Epworth sleepiness scale (ESS) for the assessment of daytime sleepiness in patients with MS. The summarized results of 48 studies demonstrate that sleepiness, as indicated by elevated ESS scores, is less prevalent and less severe than fatigue but is present in a significant proportion of patients with MS. In most cross-sectional and longitudinal studies, there was a moderate association between ESS scores and various fatigue rating scales. Longitudinal studies on the effect of wakefulness-promoting agents failed to show a consistent improvement of sleepiness or fatigue as compared to placebo. It has also been shown that daytime sleepiness is frequently associated with comorbid sleep disorders that are often underrecognized and undertreated in MS. Sleepiness and potential sleep disorders may also precipitate and perpetuate fatigue in patients with MS and should be part of the differential diagnostic assessment. To support an appropriate decision-making process, we propose a stepwise evaluation of sleepiness as compared to fatigue in patients with MS.
Topics: Fatigue; Humans; Multiple Sclerosis; Sleep Stages; Sleep Wake Disorders; Surveys and Questionnaires
PubMed: 27107751
DOI: 10.1016/j.smrv.2016.03.004