Objectives:Older adults presenting with mild cognitive impairment (MCI) have a higher risk of developing dementia and also demonstrate impairments in social cognition. This study sought to establish whether in people with MCI, poorer theory of mind (ToM) was associated with volumetric changes in the amygdala and hippocampus, as well as early changes in behaviour.Methods:One hundred and fourteen people with MCI and fifty-two older adult controls completed the Reading the Mind in the Eyes Test (RMET), while close informants (e.g., spouse/family member/friend/carer) described any current behavioural changes using the Revised Cambridge Behavioural Inventory (CBI-R). A subsample of participants completed structural magnetic resonance imaging (MRI).Results:The MCI group showed poorer performance on all neuropsychological tests administered, and moderate reductions on the RMET compared to the control group (d = .44), with greater reduction observed in those with amnestic compared to non-amnestic MCI (p = .03). While a robust correlation was identified between poorer RMET performance and smaller hippocampal volume in the control group (ρ = .53, p = .01), this relationship was not apparent in the MCI group (ρ = .21, p = .11). In the MCI group, poorer RMET performance was associated with poorer everyday skills (ρ = −.26, p = .01) assessed by the CBI-R.Conclusions:Our findings cross-validate previous reports that social cognitive deficits in ToM are a feature of MCI and also suggest that disruptions to broader neural networks are likely to be implicated. Furthermore, ToM deficits in MCI are associated with a decline in everyday skills such as writing or paying bills.
Background Memory clinics (MCs) play a key role in accurate and timely diagnoses and treatment of dementia and mild cognitive impairment. However, within Australia, there are little data available on current practices in MCs, which hinder international comparisons for best practice, harmonisation efforts and national coordination. Here, we aimed to characterise current service profiles of Australian MCs. Methods The ‘Australian Dementia Network Survey of Expert Opinion on Best Practice and the Current Clinical Landscape’ was conducted between August-September 2020 as part of a larger-scale Delphi process deployed to develop national MC guidelines. In this study, we report on the subset of questions pertaining to current practice including wait-times and post-diagnostic care. Results Responses were received from 100 health professionals representing 60 separate clinics (45 public, 11 private, and 4 university/research clinics). The majority of participants were from clinics in metropolitan areas (79%) and in general were from high socioeconomic areas. While wait-times varied, only 28.3% of clinics were able to offer an appointment within 1-2 weeks for urgent referrals, with significantly more private clinics (58.3%) compared to public clinics (19.5%) being able to do so. Wait-times were less than 8 weeks for 34.5% of non-urgent referrals. Only 20.0 and 30.9% of clinics provided cognitive interventions or post-diagnostic support respectively, with 7.3% offering home-based reablement programs, and only 12.7% offering access to group-based education. Metropolitan clinics utilised neuropsychological assessments for a broader range of cases and were more likely to offer clinical trials and access to research opportunities. Conclusions In comparison to similar countries with comprehensive government-funded public healthcare systems (i.e., United Kingdom, Ireland and Canada), wait-times for Australian MCs are long, and post-diagnostic support or evidence-based strategies targeting cognition are not common practice. The timely and important results of this study highlight a need for Australian MCs to adopt a more holistic service of multidisciplinary assessment and post-diagnostic support, as well as the need for the number of Australian MCs to be increased to match the rising number of dementia cases.
Background: Older adults living with amnestic mild cognitive impairment (aMCI) not only demonstrate impairments in Theory of Mind (ToM), relative to adults with non-amnestic MCI (naMCI), but are also at a higher risk of developing dementia. Objective: Our primary objective was to ascertain whether default mode network (DMN) functional connectivity was differentially associated with ToM abilities between MCI subgroups. Methods: Using functional magnetic resonance imaging, we investigated alterations in resting-state functional connectivity within the brain’s DMN in a sample of 43 older adults with aMCI (n = 19) and naMCI (n = 24), previously reported to demonstrate poorer ToM abilities. Results: Compared to naMCI, the aMCI subgroup revealed a significant association between poorer ToM performance and reduced functional connectivity between the bilateral temporal pole (TempP) and the left lateral temporal cortex (LTC) (LTC_L-TempP_L: b = –0.06, t(33) = –3.53, p = 0.02; LTC_L-TempP_R: b = –0.07,t(33) = –3.20, p = 0.03); between the right TempP and the dorsal medial prefrontal cortex (dMPFC) (b = –0.04, t(33) = –3.02, p = 0.03) and between the left and right TempP (b = –0.05, t(33) = –3.26, p = 0.03). In the naMCI subgroup, the opposite relationship was present between the bilateral TempP and the left LTC (Combined correlation: r = –0.47, p = 0.02), however, not between the right TempP and the dMPFC (r = –0.14, p = 0.51) or the left and right TempP (r = –0.31, p = 0.14). Conclusion: Our findings suggest that alterations in functional connectivity within the DMN involving temporal and frontal lobe regions are associated with ToM deficits in aMCI.
Background: Individuals living with Alzheimer’s disease (AD) demonstrate extensive deficits in social cognition. To date, no studies have investigated the feasibility of an intranasal oxytocin (INOT) treatment to improve social cognition in individuals living with AD. Objective: We conducted a pilot trial to determine recruitment feasibility, enrolment acceptability, and adherence to an INOT treatment to inform on the subsequent design of a future randomized controlled trial (RCT). We also estimated the effect sizes of potential social cognitive function outcome measures related to participants and their caregivers. Methods: Four individuals with AD were enrolled in a single-center, randomized, double-blind, placebo-controlled crossover trial involving a one-week treatment period with both INOT (72 IU twice-daily) and placebo. Results: All participants reported no treatment-causative or serious adverse events following repeated INOT administration. While enrolment acceptability (100%) and INOT adherence (placebo, 95%; INOT, 98%) were excellent, feasibility of recruitment was not acceptable (i.e., n = 4/58 individuals screened met inclusion criteria). However, positive/large effects were associated with secondary outcomes of self-reported health and wellbeing, caregiver ‘burden’, intimacy and interpersonal-bonding, following repeated INOT administration. No positive effects were associated with participant outcomes of social cognition. Conclusion: This pilot RCT provides first evidence that INOT administration in individuals living with AD is safe and well-tolerated. Despite limitations in sample size, moderate-to-large effect size improvements were identified in participant health outcomes as well as core social cognitive functions and ‘burden’ as reported by a caregiver. This suggests potential broad-ranging beneficial effects of INOT which should be assessed in future RCTs.
Sleep spindles are a hallmark of non-REM sleep and play a fundamental role in memory consolidation. Alterations in these spindles are emerging as sensitive biomarkers for neurodegenerative diseases of ageing. Understanding the clinical presentations associated with spindle alterations may help to elucidate the functional role of these distinct electroencephalographic oscillations and the pathophysiology of sleep and neurodegenerative disorders. Here, we use a data-driven approach to examine the sleep, memory and default mode network connectivity phenotypes associated with sleep spindle architecture in older adults (mean age = 66 years). Participants were recruited from a specialist clinic for early diagnosis and intervention for cognitive decline, with a proportion showing mild cognitive deficits on neuropsychological testing. In a sample of 88 people who underwent memory assessment, overnight polysomnography and resting state fMRI, a k-means cluster analysis was applied to spindle measures of interest: fast spindle density, spindle duration and spindle amplitude. This resulted in three clusters, characterised by preserved spindle architecture with higher fast spindle density and longer spindle duration (Cluster 1), and alterations in spindle architecture (Clusters 2 and 3). These clusters were further characterised by reduced memory (Clusters 2 and 3) and nocturnal hypoxemia, associated with sleep apnea (Cluster 3). Resting state fMRI analysis confirmed that default mode connectivity was related to spindle architecture, although directionality of this relationship differed across the cluster groups. Together these results confirm a diversity in spindle architecture in older adults, associated with clinically meaningful phenotypes, including memory function and sleep apnea. They suggest that resting state default mode connectivity during the awake state can be associated with sleep spindle architecture, however this is highly dependent on clinical phenotype. Establishing relationships between clinical and neuroimaging features and sleep spindle alterations, will advance our understanding of the bidirectional relationships between sleep changes and neurodegenerative diseases of ageing.
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