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Previous cross-lagged studies on depression and memory impairment among the elderly have revealed conflicting findings relating to the direction of influence between depression and memory impairment. The current study aims to clarify this direction of influence by examining the cross-lagged relationships between memory impairment and depression in an Asian sample of elderly community dwellers, as well as synthesizing previous relevant cross-lagged findings via a meta-analysis.
A total of 160 participants (Mage = 68.14, s.d. = 5.34) were assessed across two time points (average of 1.9 years apart) on measures of memory and depressive symptoms. The data were then fitted to a structural equation model to examine two cross-lagged effects (i.e. depressive symptoms→memory; memory→depressive symptoms). A total of 14 effect-sizes for each of the two cross-lagged directions were extracted from six studies (including the present; total N = 8324). These effects were then meta-analyzed using a three-level mixed effects model.
In the current sample, lower memory ability at baseline was associated with worse depressive symptoms levels at follow-up, after controlling for baseline depressive symptoms. However, the reverse effect was not significant; baseline depressive symptoms did not predict subsequent memory ability after controlling for baseline memory. The results of the meta-analysis revealed the same pattern of relationship between memory and depressive symptoms.
These results provide robust evidence that the relationship between memory impairment and depressive symptoms is unidirectional; memory impairment predicts subsequent depressive symptoms but not vice-versa. The implications of these findings are discussed
Primary progressive aphasia (PPA) affects a range of language and cognitive domains that impact on conversation. Little is known about conversation breakdown in the semantic variant of PPA (svPPA, also known as semantic dementia). This study investigates conversation of people with svPPA.
Dyadic conversations about everyday activities between seven individuals with svPPA and their partners, and seven control pairs were video recorded and transcribed. Number of words, turns, and length of turns were measured. Trouble-indicating behaviors (TIBs) and repair behaviors were categorized and identified as successful or not for each participant in each dyad.
In general, individuals with svPPA were active participants in conversation, taking an equal proportion of turns, but indicating a great deal of more trouble in conversation, shown by the significantly higher number of TIBs than evidenced by partners or control participants. TIBs were interactive (asking for confirmation with a shorter repetition of the original utterance or a repetition which included a request for specific information) and non-interactive (such as failing to take up or continue the topic or a minimal response) and unlike those previously reported for people with other PPA variants and dementia of the Alzheimer type. Communication behaviors of the partner were critical to conversational success.
Examination of trouble and repair in 10-min conversations of individuals with svPPA and their important communication partners has potential to inform speech pathology interventions to enhance successful conversation, in svPPA and should be an integral part of the comprehensive care plan.
The phenomenon of selective biotic extinction is commonly explained as the result of the extinction of specialized organisms and the survival of generalized organisms during a time of environmental stress. Using 48 orders of aquatic free-living arthropods, we test the hypothesis that generalized organisms tend to have longer geologic ranges than specialized organisms. The degree of specialization, as expressed through morphological complexity, is measured by the diversity of limb pairs on the arthropod body. The resulting “tagmosis value” reflects the functional differentiation of limb pairs to perform specific tasks and thus may estimate ecological specialization. No statistically significant correlation exists between an order's typical degree of morphological specialization and its geologic range. Degree of specialization is not an important determinant of evolutionary persistence at this taxonomic level. Evolutionary longevity may depend on the adaptive type (e.g., trophic role, relationship to substrate, etc.) represented by the taxon and on the assortment of these adaptive types.
Background: A large proportion of people living with human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) suffer from neurocognitive impairment (NCI). The causes of the NCI are multifold in HIV infection although a subset of HIV/AIDS patients are affected by the spectrum syndrome, HIV-associated neurocognitive disorder (HAND). We investigated the Montreal Cognitive Assessment (MoCA) in relation to clinical, demographic and laboratory findings as well as its ability to predict symptomatic HAND (sHAND) among patients with HIV/AIDS. Methods: All subjects were receiving regular HIV care including CD4+ T cell counts, plasma viral load measurements, clinical evaluations and antiretroviral therapy. The diagnosis of sHAND was based upon clinical, neuroimaging, and neuropsychological assessments.Results: Among HIV-1 seropositive subjects (n=125), ethnicity, education and employment were positively correlated with their MoCA scores (p<0.05). In contrast, polypharmacy, central nervous system penetration-effectiveness (CPE) score, antiretroviral drug exposure, substance use and nucleoside/nucleotide reverse transcriptase inhibitor side effects were negatively correlated with MoCA scores (p<0.05). Of note, MoCA scores were not associated with CD4 T cell nadir levels, age, peak viral load, or veterans aging cohort study index. In subjects with or without sHAND, mean MoCA scores differed (sHAND, 22.8±3.51; non-HAND 25.2±2.64) (p<0.05) with a receiver operating characteristic curve showing an area under curve of 0.71 and an optimal MoCA cut-off value of 23.5 when compared to the established diagnostic paradigm. Conclusions: MoCA scores were generally lower in this HIV/AIDS population compared to reported scores in the general population. MoCA performance was associated with multiple clinical variables but displayed limited predictive utility in detecting sHAND.
It is unknown whether prodromal services improve outcomes in those who go on to develop psychosis, and whether these patients are demographically different from the overall first-episode population.
To compare sociodemographic features, duration of untreated psychosis, hospital admission and frequency of compulsory treatment in the first year after the onset of psychosis in patients who present to prodromal services with patients who did not present to services until the first episode of psychosis.
We compared two groups of patients with first-episode psychosis: one who made transition after presenting in the prodromal phase and the other who had presented with a first episode.
The patients who had presented before the first episode were more likely to be employed and less likely to belong to an ethnic minority group. They had a shorter duration of untreated psychosis, and were less likely to have been admitted to hospital and to have required compulsory treatment.
Patients who develop psychosis after being engaged in the prodromal phase have a better short-term clinical outcome than patients who do not present until the first episode. Patients who present during first episodes may be more likely to have sociodemographic features associated with relatively poor outcomes.
Sand quarrying in 1989 at Sand Fiold, Sandwick, in Orkney resulted in the accidental discovery of a rock-cut chamber containing a cist. Subsequent excavation revealed that this cist had a number of unusual features. The cist slabs had been fitted together exceptionally well and the completed cist was designed to be re-opened by the removal of a side slab. Within the chamber, access was provided to the opening side of the cist and a relieving structure was built over its capstone.
The cist contained cremation and inhumation burials that had been inserted on more than one occasion; as its builders intended. A collection of poorly preserved unburnt bone was found to comprise the remains of two individuals: a young adult and a foetus. Two collections of cremated bone, each derived from a single adult, were also present; one in a Food Vessel Urn, the second forming a pile on the floor and containing two burnt antler tines and two unburnt human teeth. The un-urned cremation deposit and the unburnt bones had been covered in mats of plant fibres derived from grass and sedge. The urn had been lined with basketry, also made from grass. Outside the cist, an exceptionally large collection of fuel ash slag (FAS), derived from a cremation pyre, had been deposited between the cist and the wall of the rock-cut chamber.
Radiocarbon dates indicate that the site and its contents had a long history. The FAS and the foetus skeleton date to 2900–2500 cal BC. Between 2200 and 1900 cal BC the urned cremation and young adult human bones were inserted and charcoal was deposited in the foundation slots for the back wall of the cist. The deposition of the un-urned cremation was dated to 1000–800 cal BC, some 900 years later, when the urn had already fallen over and broken. At this time, it is assumed that the urn was restored to an upright position and propped with stones, while the stone lid for the urn was reused in the foundation slot of the left-hand side of the cist. Reuse and refurbishment over two millennia seem evidenced in the results from this cist.
Ethnic variations have previously been identified in the duration of untreated psychosis (DUP) and pathways into psychiatric services. These have not been examined in the context of early intervention services, which may alter these trajectories.
To explore ethnic differences in the nature and duration of pathways into early intervention services.
In a naturalistic cohort study, data were collected for 1024 individuals with psychotic disorders accepted for case management by eight London early intervention services.
Duration of untreated psychosis was prolonged in the White British group compared with most other ethnic groups. White British individuals were more likely to make contact with their general practitioner and less likely to be seen within emergency medical services. All Black patient groups were more likely than their White British counterparts to experience involvement of criminal justice agencies.
Variations continue to exist in how and when individuals from different ethnic groups access early intervention services. These may account for disparities in DUP.
A process has been developed to manufacture biodegradable composite foams of poly(DL-lactic- co-glycolic acid) (PLGA) and hydroxyapatite short fibers for use in bone regeneration. The processing technique allows the manufacture of three-dimensional foam scaffolds and involves the formation of a composite material consisting of a porogen material (either gelatin microspheres or salt particles) and hydroxyapatite short fibers embedded in a PLGA matrix. After the porogen is leached out, an open-cell composite foam remains which has a pore size and morphology defined by the porogen. The foam porosity can be controlled by altering the volume fraction of porogen used to make the composite material. Foams made using NaCl particles as a porogen were manufactured with porosities as high as 0.84±0.01 (n=3). The short hydroxyapatite fibers served to reinforce the PLGA. The compressive yield strength of foams manufactured using gelatin microspheres as a porogen was found to increase with fiber content. Foams with compressive yield strengths up to 2.82±0.63 MPa (n=3) with porosities of 0.47±0.01 (n=3) were manufactured using 30% by weight hydroxyapatite fibers in the initial composite prior to leaching. These composite foams with improved mechanical properties may also be expected to have enhanced osteoconductivity and hence provide a novel material which may prove useful in the field of bone regeneration.
We present a novel method for manufacturing three-dimensional, biodegradable poly(DL-lactic-co-glycolic acid) (PLGA) foam scaffolds for use in bone regeneration. The technique involves the formation of a composite material consisting of gelatin microspheres surrounded by a PLGA matrix. The gelatin microspheres are leached out leaving an open-cell foam with a pore size and morphology defined by the gelatin microspheres. The foam porosity can be controlled by altering the volume fraction of gelatin used to make the composite material. PLGA 50:50 was used as a model degradable polymer to establish the effect of porosity, pore size, and degradation on foam mechanical properties. The compressive strengths and moduli of PLGA 50:50 foams were found to decrease with increasing porosity but were largely unaffected by pore size. Foams with compressive strengths up to 2.5 MPa were manufactured. From in vitro degradation studies we established that for PLGA 50:50 foams the mechanical properties declined in parallel with the decrease in molecular weight. Below a weight average molecular weight of 10,000 the foam had very little mechanical strength (0.02 MPa). These results indicate that PLGA 50:50 would not be suitable as a scaffold material for bone regeneration. However, the dependence of mechanical properties on porosity, pore size, and degree of degradation which we have determined will aid us in designing a PLGA foam (with a comonomer ratio other than 50:50) suitable for bone regeneration.
Motivated by the search for a body of mathematical theory to support the semantics of computational effects, we first recall the relationship between Lawvere theories and monads on Set. We generalise that relationship from Set to an arbitrary locally presentable category such as Poset and ωCpo or functor categories such as [Inj, Set] and [Inj, ωCpo]. That involves allowing the arities of Lawvere theories to be extended to being size-restricted objects of the locally presentable category. We develop a body of theory at this level of generality, in particular explaining how the relationship between generalised Lawvere theories and monads extends Gabriel–Ulmer duality.
We hypothesized that specific neuropsychological deficits were associated with specific patterns of atrophy. A magnetic resonance imaging volumetric study and a neuropsychological protocol were obtained for patients with several frontotemporal lobar dementia phenotypes including a social/dysexecutive (SOC/EXEC, n = 17), progressive nonfluent aphasia (n = 9), semantic dementia (n = 7), corticobasal syndrome (n = 9), and Alzheimer’s disease (n = 21). Blinded to testing results, patients were partitioned according to pattern of predominant cortical atrophy; our partitioning algorithm had been derived using seriation, a hierarchical classification technique. Neuropsychological test scores were regressed versus these atrophy patterns as fixed effects using the covariate total atrophy as marker for disease severity. The results showed the model accounted for substantial variance. Furthermore, the “large-scale networks” associated with each neuropsychological test conformed well to the known literature. For example, bilateral prefrontal cortical atrophy was exclusively associated with SOC/EXEC dysfunction. The neuropsychological principle of “double dissociation” was supported not just by such active associations but also by the “silence” of locations not previously implicated by the literature. We conclude that classifying patients with degenerative dementia by specific pattern of cortical atrophy has the potential to predict individual patterns of cognitive deficits. (JINS, 2009, 15, 459–470.)
Over 60,000 Canadians are infected with human immunodeficiency virus (HIV). Greater than 50% of these individuals will develop a neurological disorder despite the availability of highly active antiretroviral therapy. HIV causes nervous system disease at all stages of infection with adverse effects on quality of life, adherence to medications, employment and survival. These disorders include opportunistic infections in addition to distinct HIV-associated neurological syndromes and undesirable treatment-related effects. The latter two groups of disorders are often undiagnosed and untreated in both adolescents and adults. Direct HIV infection of central nervous system causes HIV-associated dementia, which is a progressive subcortical dementia. HIV infection of the peripheral nervous system produces a painful sensory neuropathy termed distal sensory polyneuropathy, which may be exacerbated by several antiretroviral drugs. Other important HIV-induced neurological disorders include vacuolar myelopathy and an increased risk of seizures. Future issues that will confound the presentation and treatment of HIV-induced nervous system disorders include the increasing prevalence of drug-resistant HIV strains, increasing age of HIV-infected patients, hepatitis C virus co-infection and the Immune Reconstitution Inflammatory Syndrome. Herein, we review the clinical presentations, underlying pathogenesis and treatments of this burgeoning group of neurological disorders.
Despite the increasing development of early intervention services for psychosis, little is known about their cost-effectiveness. We assessed the cost-effectiveness of Outreach and Support in South London (OASIS), a service for people with an at-risk mental state (ARMS) for psychosis.
The costs of OASIS compared to care as usual (CAU) were entered in a decision model and examined for 12- and 24-month periods, using the duration of untreated psychosis (DUP) and rate of transition to psychosis as key parameters. The costs were calculated on the basis of services used following referral and the impact on employment. Sensitivity analysis was used to test the robustness of all the assumptions made in the model.
Over the initial 12 months from presentation, the costs of the OASIS intervention were £1872 higher than CAU. However, after 24 months they were £961 less than CAU.
This model suggests that services that permit early detection of people at high risk of psychosis may be cost saving.
Financial capacity is a complex instrumental activity of daily living critical to independent functioning of older adults and sensitive to impairment in patients with amnestic mild cognitive impairment (MCI) and Alzheimer’s disease (AD). However, little is known about the neurocognitive basis of financial impairment in dementia. We developed cognitive models of financial capacity in cognitively healthy older adults (n = 85) and patients with MCI (n = 113) and mild AD (n = 43). All participants were administered the Financial Capacity Instrument (FCI) and a neuropsychological test battery. Univariate correlation and multiple regression procedures were used to develop cognitive models of overall FCI performance across groups. The control model (R2 = .38) comprised (in order of entry) written arithmetic skills, delayed story recall, and simple visuomotor sequencing. The MCI model (R2 = .69) comprised written arithmetic skills, visuomotor sequencing and set alternation, and race. The AD model (R2 = .65) comprised written arithmetic skills, simple visuomotor sequencing, and immediate story recall. Written arithmetic skills (WRAT-3 Arithmetic) was the primary predictor across models, accounting for 27% (control model), 46% (AD model), and 55% (MCI model) of variance. Executive function and verbal memory were secondary model predictors. The results offer insight into the cognitive basis of financial capacity across the dementia spectrum of cognitive aging, MCI, and AD. (JINS, 2009, 15, 258–267.)