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Background: Cognitive screening tools enable the detection of cognitive impairment, facilitate timely intervention, inform clinical care, and allow long-term planning. The Montreal Cognitive Assessment for people with hearing impairment (MoCA-H) was developed as a reliable cognitive screening tool for people with hearing loss. Using the same methodology across four languages, this study examined whether cultural or linguistic factors affect the performance of the MoCA-H., Methods: The current study investigated the performance of the MoCA-H across English, German, French, and Greek language groups (n = 385) controlling for demographic factors known to affect the performance of the MoCA-H., Results: In a multiple regression model accounting for age, sex, and education, cultural-linguistic group accounted for 6.89% of variance in the total MoCA-H score. Differences between languages in mean score of up to 2.6 points were observed., Conclusions: Cultural or linguistic factors have a clinically significant impact on the performance of the MoCA-H such that optimal performance cut points for identification of cognitive impairment derived in English-speaking populations are likely inappropriate for use in non-English speaking populations. To ensure reliable identification of cognitive impairment, it is essential that locally appropriate performance cut points are established for each translation of the MoCA-H., (© 2024 The Author(s). Journal of the American Geriatrics Society published by Wiley Periodicals LLC on behalf of The American Geriatrics Society.)

Background: Existing traditional cognitive screening tools for dementia have various limitations, including overreliance on tests assessing verbal memory and, to a lesser extent, on some aspects of executive functioning. Comprehensive neuropsychological assessment is sensitive to impairment but time-intensive and expensive. Virtual reality may provide a dynamic and unique understanding of cognitive performance and increase the ecological validity of cognitive assessment. The use of virtual reality in screening for cognitive function in older persons is promising, but evidence for its use remains sparse., Objective: Our primary aim was to examine the feasibility and acceptability of a newly developed, virtual reality assessment module, 'Leaf Café', a computer-based program that assesses cognition in an engaging, efficient, and ecologically relevant way. The secondary aim was to assess the ability of the module to discriminate between performances of younger and older adults., Methods: A cross-sectional study was carried out in Sydney, Australia, targeting adults aged 18 years and above. Participants completed a traditional cognitive screening tool (Telephone Interview for Cognitive Status-Modified, TICS-M) and Leaf Café, a low-immersive virtual reality module designed to evaluate learning and memory, perceptual-motor function, and executive functioning. The total performance score for each participant, ranging from 0 to 180, was correlated with their cognitive performance assessed by TICS-M, using Pearson's correlation coefficient. Following module completion, participants were presented with an open and closed-question survey to capture their perceptions, attitudes, and feedback on the module, encompassing practicality, acceptability, and enjoyment. Both descriptive and content analyses were employed to interpret the obtained data., Results: A sample of 131 participants (mean age 54.9 years, SD = 20.8, range 20-85) took part. The majority were female (71.8%) and born in an English-speaking country (75.8%). The mean amount of time spent in the module was 32.8 min (SD = 13.3) with a mean module score of 107.6 (SD = 38.7). Most participants completed the highest level (5; 80.5%). There was a significant correlation between Leaf Café total scores with TICS-M cognitive scores overall, and for both younger (aged 18-64 years) and older adult (aged 65 + years) groups. No significant difference was found on performance between age groups on TICS-M performance, however, younger adults had significantly better performance on the Leaf Café module than older adults (M = 124.1 vs 95.9; p < .001). Participants had similar response proportions regarding user experience with most agreeing that the module was easy to use (84%) and to navigate (85%). Compared with younger adults, older adults had lower rates of agreement on the module's design (36.8% vs 64.3%; p = .020) and support experienced (20.5% vs 53.6%; p = .007). Participants highlighted the significance of practicality and the cognitive challenges presented by the module, in terms of memory strain and user interface concerns. Feedback encompassed different opinions on the usefulness of music, with suggestions for improvements centred around clearer instructions, varied game dynamics, and considerations for diverse user needs., Conclusions: Leaf Café is a feasible and acceptable tool to be used for screening for cognitive impairment in older adults and has real-world assessment value. Further verification on the game's utility in detecting cognitive impairment is required., (© 2024. The Author(s).)

Addressing midlife hearing loss could prevent up to 9% of new cases of dementia, the highest of any potentially modifiable risk factor identified in the 2017 commissioned report in The Lancet. In Australia, hearing loss is the second-most common chronic health condition in older people, affecting 74% of people aged over 70. Estimates indicate that people with severe hearing loss are up to 5-times more likely to develop dementia, but these estimates vary between studies due to methodological limitations. Using data from the Sydney Memory and Aging Study, in which 1,037 Australian men and women aged between 70 and 90 years were enrolled and completed biennial assessments from 2005-2017, investigations between hearing loss and baseline cognitive performance as well as longitudinal risk of neurocognitive disorder were undertaken. Individuals who reported moderate-to-severe hearing difficulties had poorer cognitive performances in the domains of Attention/Processing Speed and Visuospatial Ability, and on an overall index of Global Cognition, and had a 1.5-times greater risk for the neurocognitive disorder during 6-years' follow-up. Hearing loss independently predicted risk for MCI but not dementia. The presence of hearing loss is an important consideration for neuropsychological case formulation in older adults with cognitive impairment. Hearing loss may increase cognitive load, resulting in observable cognitive impairment on neuropsychological testing. Individuals with hearing loss who demonstrate impairment in non-amnestic domains may experience benefits from the provision of hearing devices; This study provides support for a randomized control trial of hearing devices for improvement of cognitive function in this group.

Objectives: The criteria for objective memory impairment in mild cognitive impairment (MCI) are vaguely defined. Aggregating the number of abnormal memory scores (NAMS) is one way to operationalise memory impairment, which we hypothesised would predict progression to Alzheimer's disease (AD) dementia., Methods: As part of the Australian Imaging, Biomarkers and Lifestyle Flagship Study of Ageing, 896 older adults who did not have dementia were administered a psychometric battery including three neuropsychological tests of memory, yielding 10 indices of memory. We calculated the number of memory scores corresponding to z ≤ -1.5 (i.e., NAMS) for each participant. Incident diagnosis of AD dementia was established by consensus of an expert panel after 3 years., Results: Of the 722 (80.6%) participants who were followed up, 54 (7.5%) developed AD dementia. There was a strong correlation between NAMS and probability of developing AD dementia (r = .91, p = .0003). Each abnormal memory score conferred an additional 9.8% risk of progressing to AD dementia. The area under the receiver operating characteristic curve for NAMS was 0.87 [95% confidence interval (CI) .81-.93, p < .01]. The odds ratio for NAMS was 1.67 (95% CI 1.40-2.01, p < .01) after correcting for age, sex, education, estimated intelligence quotient, subjective memory complaint, Mini-Mental State Exam (MMSE) score and apolipoprotein E ϵ4 status., Conclusions: Aggregation of abnormal memory scores may be a useful way of operationalising objective memory impairment, predicting incident AD dementia and providing prognostic stratification for individuals with MCI.

The longevity gene Klotho (KL), specifically the functional KL-VS variant, has previously been associated with cognition and rates of cognitive decline. This study aimed to determine whether KL-VS associations with cognition were observable in preclinical Alzheimer's disease (AD). The study also aimed to determine whether there was a combined influence of KL-VS, neocortical amyloid-β (Aβ) burden, and carriage of the apolipoprotein E (APOE) ε4 allele on cognitive decline. This study involved 581 Aβ-imaged, cognitively normal older adults, enrolled in the Australian Imaging, Biomarkers and Lifestyle Study of Aging. Linear mixed effects models revealed no significant associations between KL-VS and cognitive decline independently or in combination with Aβ burden and APOE ε4 genotype. Overall, previous associations reported between KL-VS and cognitive decline are not observed at the preclinical stages of AD. Furthermore, the results do not support the hypothesis that KL-VS has a modifying effect on Aβ burden and APOE ε4-driven cognitive decline in preclinical AD., (Copyright © 2019 Elsevier Inc. All rights reserved.)

The ability to read irregularly spelled words is commonly used to estimate premorbid intelligence, as this ability has been thought to be resistant to early effects of neurodegenerative disorders. However, studies evaluating decline of this skill in Alzheimer's disease (AD) have produced conflicting results. Irregular word reading was assessed three times over 36 months in a large (N = 995) sample, including healthy control, AD, and Mild Cognitive Impairment (MCI) groups. At baseline, MCI and AD groups read correctly an average of 3.01 and 7.39 fewer words, respectively, than healthy controls. The MCI group's performance remained stable during the study, but the AD group declined. Importantly, the observed decline was likely an underestimate, as significant numbers of the AD participants (42.6%) could not complete the task at follow-up. Use of alternate (e.g., demographics-based) methods is advised to augment or replace word pronunciation in estimating premorbid intelligence in individuals with even mild AD. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Background: Given the long preclinical disease course of Alzheimer disease (AD) pathology, novel treatments may be more efficacious if administered before the emergence of dementia. Thus, accurate prediction of who will develop AD dementia is of key importance in selecting individuals for trials of treatment and may become crucial for future selection of patients for therapy., Methods: As part of the Australian Imaging, Biomarkers and Lifestyle Flagship Study of Ageing, 901 individuals who did not have dementia were recruited. We assigned individuals according to Petersen criteria and Winblad criteria for Mild Cognitive Impairment (MCI) at baseline. We then stratified individuals with amnestic MCI into 2 groups according to the severity of their memory impairment on baseline neuropsychological assessment. Incident diagnosis of AD dementia was established by consensus of an expert panel at 36 months., Results: At 36 months, 725 (80.5%) participants were followed up, 54 (7.4%) of whom developed AD dementia. Subjects with amnestic MCI according to Petersen criteria were more likely to develop AD dementia [positive predictive value; PPV, 24.1%; 95% confidence interval (CI), 18.4-30.6] than healthy controls (PPV, 1.0%; 95% CI, 0.3-2.3). Winblad criteria were also effective, with multiple domain amnestic MCI being most accurate at predicting AD dementia (PPV, 47.3%; 95% CI, 33.7-61.2). Finally, more severe amnestic impairment below the median was useful for predicting the development of AD dementia in single domain amnestic MCI (PPV, 28.1%; 95% CI, 17.0-41.5) and in multiple domain amnestic MCI (PPV, 65.7%; 95% CI, 47.8-80.9)., Conclusions: Memory impairment per se, impairment in multiple cognitive domains and severity of memory impairment were all associated with greater risk of developing AD dementia in this sample. Characterizing the severity of memory impairment may provide prognostic stratification within Petersen or Winblad taxonomies of amnestic MCI.

A single nucleotide polymorphism, rs17070145, in the KIdney and BRAin expressed protein (KIBRA) gene has been associated with cognition and hippocampal volume in cognitively normal (CN) individuals. However, the impact of rs17070145 on longitudinal cognitive decline and hippocampal atrophy in CN adults at greatest risk of developing Alzheimer's disease is unknown. We investigated the impact rs17070145 has on the rate of cognitive decline and hippocampal atrophy over six years in 602 CN adults, with known brain Aβ-amyloid levels and whether there is an interactive effect with APOE genotype. We reveal that whilst limited independent effects of KIBRA genotype were observed, there was an interaction with APOE in CN adults who presented with high Aβ-amyloid levels across study duration. In comparison to APOE ε4-ve individuals carrying the rs17070145-T allele, significantly faster rates of cognitive decline (global, p = 0.006; verbal episodic memory, p = 0.004), and hippocampal atrophy (p = 0.04) were observed in individuals who were APOE ε4 + ve and did not carry the rs17070145-T allele. The observation of APOE effects in only non-carriers of the rs17070145-T allele, in the presence of high Aβ-amyloid suggest that carriers of the rs17070145-T allele are conferred a level of resilience to the detrimental effects of high Aβ-amyloid and APOE ε4.

Background: With the exception of APOE, genetic variants associated with increased Alzheimer's disease (AD) risk are characterized by small effect sizes. Polygenic risk scores (PRS) have shown utility in predicting AD risk; however, their utility for predicting decline in cognition at preclinical stages of AD is poorly understood., Objective: To validate associations of a 22-variant AD-risk-weighted PRS with AD risk and related biomarkers and to assess its utility to predict cognitive decline., Methods: The PRS was evaluated with respect to brain amyloid-β (Aβ) burden, cerebrospinal fluid (CSF) Aβ42, total-tau, and phospho-tau, and decline in cognition in 643 (570 cognitively normal (CN), 73 AD) PET-imaged participants from the longitudinal Australian Imaging, Biomarkers and Lifestyle (AIBL) Study of Ageing. Cognition was assessed using three composite measures; global cognition, verbal episodic memory, and a Pre-Alzheimer's Cognitive Composite (PACC)., Results: PRS, both with and without APOE, were positively correlated with brain Aβ burden, CSF total-tau, and phospho-tau in CN older adults. Further, in CN biomarker positive (Aβhigh) participants, significant associations were observed with baseline and longitudinal cognition. However, this association was not observed after the removal of APOE. Partitioning the PRS into quartiles revealed that the PRS associations with cognitive decline in Aβhigh CN older adults is due to a saturating effect of APOE genotype., Conclusions: An AD-risk-weighted PRS is associated with cognitive decline in CN older adults. However, this association is absent when APOE genotype is excluded from the PRS, suggesting that associations with cognitive decline in this model of polygenic risk are driven by APOE genotype alone. Further research is needed to define appropriate PRSs with greater utility for predicting preclinical AD cognitive decline.

Subjective memory decline (SMD) is a heterogeneous condition. While SMD might be the earliest sign of Alzheimer's disease (AD), it also occurs in aging and various neurological, medical, and psychiatric conditions. Identifying those with higher risk to develop dementia is thus a major challenge. We tested a novel disease severity index generated by multivariate data analysis with numerous structural MRI measures as input. The index was used to identify SMD individuals with high risk of progression to mild cognitive impairment (MCI) or AD. A total of 69 healthy controls, 86 SMD, 45 MCI, and 38 AD patients were included. Subjects were followed up for 7.5 years. Clinical, cognitive, PET amyloid imaging and APOE ε4 data were used as outcome variables. The results showed that SMD evidenced cognitive performance intermediate between healthy controls and MCI. The disease severity index identified eleven (13%) SMD individuals with an AD-like pattern of brain atrophy. These individuals showed lower cognitive performance, increased CDR-SOB, higher amyloid burden and worse clinical progression (6.2 times higher likelihood to develop MCI, dementia or die than healthy controls). The current disease severity index may have relevance for clinical practice, as well as for selecting appropriate individuals for clinical trials.

Objective: We assessed a blood-based signature, which previously demonstrated high accuracy at stratifying individuals with high or low neocortical β-amyloid burden (NAB), to determine whether it could also identify individuals at risk of progression to Alzheimer disease (AD) within 54 months., Methods: We generated the blood-based signature for 585 healthy controls (HCs) and 74 participants with mild cognitive impairment (MCI) from the Australian Imaging, Biomarkers and Lifestyle Study who underwent clinical reclassification (blinded to biomarker findings) at 54-month follow-up. The individuals were split into estimated high and low NAB groups based on a cutoff of 1.5 standardized uptake value ratio. We assessed the predictive accuracy of the high and low NAB groupings based on progression to mild cognitive impairment or AD according to clinical reclassification at 54-month follow-up., Results: Twelve percent of HCs with estimated high NAB progressed in comparison to 5% of HCs with estimated low NAB (odds ratio = 2.4). Forty percent of the participants with MCI who had estimated high NAB progressed in comparison to 5% of the participants with MCI who had estimated low NAB (odds ratio = 12.3). These ratios are in line with those reported for Pittsburgh compound B-PET results. Individuals with estimated high NAB had faster rates of memory decline than those with estimated low NAB., Conclusion: These findings suggest that a simple blood-based signature not only provides estimates of NAB but also predicts cognitive decline and disease progression, identifying individuals at risk of progressing toward AD at the prodromal and preclinical stages., (© 2016 American Academy of Neurology.)

Background: Brain amyloid β (Aβ) deposition and neurodegeneration have been documented in about 50-60% of cognitively healthy elderly individuals (aged 60 years or older). The long-term cognitive consequences of the presence of Alzheimer's disease pathology and neurodegeneration, and whether they have an independent or synergistic effect on cognition, are unclear. We aimed to characterise the long-term clinical and cognitive trajectories of healthy elderly individuals using a two-marker (Alzheimer's disease pathology and neurodegeneration) imaging construct., Methods: Between Nov 3, 2006, and Nov 25, 2014, 573 cognitively healthy individuals in Melbourne and Perth, Australia, (mean age 73·1 years [SD 6·2]; 58% women) were enrolled in the Australian Imaging, Biomarker and Lifestyle (AIBL) study. Alzheimer's disease pathology (A) was determined by measuring Aβ deposition by PET, and neurodegeneration (N) was established by measuring hippocampal volume using MRI. Individuals were categorised as A(-)N(-), A(+)N(-), A(+)N(+), or suspected non-Alzheimer's disease pathophysiology (A(-)N(+), SNAP). Clinical progression, hippocampal volume, standard neuropsychological tests, and domain-specific and global cognitive composite scores were assessed over 6 years of follow-up. Linear mixed effect models and a Cox proportional hazards model of survival were used to evaluate, compare, and contrast the clinical, cognitive, and volumetric trajectories of patients in the four AN categories., Findings: 50 (9%) healthy individuals were classified as A(+)N(+), 87 (15%) as A(+)N(-), 310 (54%) as A(-)N(-), and 126 (22%) as SNAP. APOE ε4 was more frequent in participants in the A(+)N(+) (27; 54%) and A(+)N(-) (42; 48%) groups than in the A(-)N(-) (66; 21%) and SNAP groups (23; 18%). The A(+)N(-) and A(+)N(+) groups had significantly faster cognitive decline than the A(-)N(-) group (0·08 SD per year for AIBL-Preclinical AD Cognitive Composite [PACC]; p<0·0001; and 0·25; p<0·0001; respectively). The A (+)N(+) group also had faster hippocampal atrophy than the A(-)N(-) group (0·04 cm(3) per year; p=0·02). The SNAP group generally did not show significant decline over time compared with the A(-)N(-) group (0·03 SD per year [p=0·19] for AIBL-PACC and a 0·02 cm(3) per year increase [p=0·16] for hippocampal volume), although SNAP was sometimes associated with lower baseline cognitive scores (0·20 SD less than A(-)N(-) for AIBL-PACC). Within the follow-up, 24% (n=12) of individuals in the A(+)N(+) group and 16% (n=14) in the A(+)N(-) group progressed to amnestic mild cognitive impairment or Alzheimer's disease, compared with 9% (n=11) in the SNAP group., Interpretation: Brain amyloidosis, a surrogate marker of Alzheimer's disease pathology, is a risk factor for cognitive decline and for progression from preclinical stages to symptomatic stages of the disease, with neurodegeneration acting as a compounding factor. However, neurodegeneration alone does not confer a significantly different risk of cognitive decline from that in the group with neither brain amyloidosis or neurodegeneration., Funding: CSIRO Flagship Collaboration Fund and the Science and Industry Endowment Fund (SIEF), National Health and Medical Research Council, the Dementia Collaborative Research Centres programme, McCusker Alzheimer's Research Foundation, and Operational Infrastructure Support from the Government of Victoria., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Background: Information provided by an informant about a patient with cognitive change is an essential component of clinical history taking. How an informant's report relates to the patient's phenomenological experience of memory loss is yet to be understood. The aim was to examine patterns of relationships between self and informant reports from a phenomenological perspective., Methods: Forty-three healthy non-memory complainers (HC-NMC), 37 healthy subjective memory complainers (HC-SMC) and 43 individuals with mild cognitive impairment (MCI) were administered a semi-structured interview, which measured their concerns of frequency of memory lapses and impact on mood. Informants responded to questionnaires., Results: Self-reported concerns of increasing frequency and impacted mood related to informant concerns in HC-SMCs. MCI with lower informant concern showed a similar pattern to HC-SMCs on complaints of increasing frequency. In those with higher informant concern, self-reports markedly separated from informant concern. The MCI group with greater informant concern performed comparatively poor on verbal and non-verbal memory measures., Conclusions: Our results suggest that the association between self-reported and informant memory concerns is moderated by MCI severity. Self and informant reports of increasing memory lapse frequency aligned in HC-SMC and MCIs with low informant concern, suggesting a similar dyadic experience of memory change. In MCIs with greater informant concern, the pattern changed exposing a changing insight with advancing memory impairment. These individuals are potentially reflecting a 'forgetting that they forget' phenomenon in elements of their concern., (© The Author 2015. Published by Oxford University Press on behalf of the British Geriatrics Society. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

The ε4 polymorphism of the APOE gene confers a substantially increased risk of developing Alzheimer's disease. However, the influence of the ε4 allele on age-related cognitive functioning is more contentious. Previously, we demonstrated relatively little evidence for a role of the ε4 allele on baseline cognitive performance in older adults in the Australian Imaging, Biomarkers and Lifestyle (AIBL) Study of Ageing (Foster et al., 2013). We here investigated whether the APOE ε4 allele influenced cognitive status over time when the AIBL cohort was studied longitudinally over a 3-year period. The AIBL neuropsychological test battery was administered at baseline, after 18 months and again after 36 months. Participants comprised 764 Healthy Controls and 131 Mild Cognitively Impaired individuals enrolled in the AIBL Study of Ageing. We compared individuals within each group with and without an ε4 allele. Healthy Controls with an ε4 allele manifested a modest acceleration in cognitive decline over 36 months on measures of verbal episodic memory. By contrast, Mild Cognitively Impaired individuals with an ε4 allele showed increased cognitive decline across a range of cognitive tasks, putatively reflecting early cognitive signs of Alzheimer's disease. Given the long prodromal period that has been noted in late onset Alzheimer's disease, we suggest that these findings are consistent with a prodromal account rather than a phenotypic account of ε4-related cognitive ageing., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Background: The Australian Imaging, Biomarkers and Lifestyle (AIBL) Flagship Study of Ageing is a prospective study of 1,112 individuals (211 with Alzheimer's disease (AD), 133 with mild cognitive impairment (MCI), and 768 healthy controls (HCs)). Here we report diagnostic and cognitive findings at the first (18-month) follow-up of the cohort. The first aim was to compute rates of transition from HC to MCI, and MCI to AD. The second aim was to characterize the cognitive profiles of individuals who transitioned to a more severe disease stage compared with those who did not., Methods: Eighteen months after baseline, participants underwent comprehensive cognitive testing and diagnostic review, provided an 80 ml blood sample, and completed health and lifestyle questionnaires. A subgroup also underwent amyloid PET and MRI neuroimaging., Results: The diagnostic status of 89.9% of the cohorts was determined (972 were reassessed, 28 had died, and 112 did not return for reassessment). The 18-month cohort comprised 692 HCs, 82 MCI cases, 197 AD patients, and one Parkinson's disease dementia case. The transition rate from HC to MCI was 2.5%, and cognitive decline in HCs who transitioned to MCI was greatest in memory and naming domains compared to HCs who remained stable. The transition rate from MCI to AD was 30.5%., Conclusion: There was a high retention rate after 18 months. Rates of transition from healthy aging to MCI, and MCI to AD, were consistent with established estimates. Follow-up of this cohort over longer periods will elucidate robust predictors of future cognitive decline.

Purpose: We examined whether differences in findings of studies examining mild cognitive impairment (MCI) were associated with recruitment methods by comparing sample characteristics in two contemporaneous Australian studies, using population-based and convenience sampling., Method: The Sydney Memory and Aging Study invited participants randomly from the electoral roll in defined geographic areas in Sydney. The Australian Imaging, Biomarkers and Lifestyle Study of Ageing recruited cognitively normal (CN) individuals via media appeals and MCI participants via referrals from clinicians in Melbourne and Perth. Demographic and cognitive variables were harmonized, and similar diagnostic criteria were applied to both samples retrospectively., Results: CN participants recruited via convenience sampling were younger, better educated, more likely to be married and have a family history of dementia, and performed better cognitively than those recruited via population-based sampling. MCI participants recruited via population-based sampling had better memory performance and were less likely to carry the apolipoprotein E ε4 allele than clinically referred participants but did not differ on other demographic variables., Conclusion: A convenience sample of normal controls is likely to be younger and better functioning and that of an MCI group likely to perform worse than a purportedly random sample. Sampling bias should be considered when interpreting findings., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Background: Autobiographical memory (ABM) refers to the recollection of individual experiences, while personal semantic memory (PSM) refers to personally relevant, but shared, facts. Mild cognitive impairment (MCI) is routinely diagnosed with the aid of neuropsychological tests, which do not tap the ABM and PSM domains., Objective: We aimed to characterize the nature of ABM and PSM retrieval in cognitively healthy (HC) memory complainers, non-memory complainers, and MCI participants, and to investigate the relationship between neuropsychological tests and personal memory., Methods: Gender- and education-matched participants (HC = 80 and MCI = 43) completed the Episodic ABM Interview (EAMI) and a battery of neuropsychological tests., Results: ABM and PSM did not differ between complainers and non-complainers, but were poorer in MCI participants, after accounting for age and depressive symptomatology. There were significant associations between personal memory and objective memory measures were found in MCI participants, but standard cognitive measures were more sensitive to MCI., Conclusion: Personal memory was compromised in MCI, reflected by lower scores on the EAMI. Memory complaining, assessed by current approaches, did not have an impact on personal memory. Standard subjective questionnaires might not reflect the sorts of concerns that bring individuals to clinical attention. Understanding personal memory function in the elderly may aid in the development of a more sensitive measure of subjective memory concerns.

Background: Assessment of risk and early diagnosis of Alzheimer's disease (AD) is a key to its prevention or slowing the progression of the disease. Previous research on risk factors for AD typically utilizes statistical comparison tests or stepwise selection with regression models. Outcomes of these methods tend to emphasize single risk factors rather than a combination of risk factors. However, a combination of factors, rather than any one alone, is likely to affect disease development. Genetic algorithms (GA) can be useful and efficient for searching a combination of variables for the best achievement (eg. accuracy of diagnosis), especially when the search space is large, complex or poorly understood, as in the case in prediction of AD development., Results: Multiple sets of neuropsychological tests were identified by GA to best predict conversions between clinical categories, with a cross validated AUC (area under the ROC curve) of 0.90 for prediction of HC conversion to MCI/AD and 0.86 for MCI conversion to AD within 36 months., Conclusions: This study showed the potential of GA application in the neural science area. It demonstrated that the combination of a small set of variables is superior in performance than the use of all the single significant variables in the model for prediction of progression of disease. Variables more frequently selected by GA might be more important as part of the algorithm for prediction of disease development.

Background: To date evidence of the relationship between cognition and Aβ amyloid during the early stages of Alzheimer's Disease (AD) has been inconsistent. This study aimed to describe the nature and magnitude of the relationship between Aβ amyloid and cognitive performance of individuals without dementia., Methods: Composite cognitive measures were developed from the Australian Imaging Biomarkers and Lifestyle study neuropsychological test battery using data from 768 healthy older adults and 133 adults with mild cognitive impairment (MCI). A subgroup of this sample (174 healthy, 53 MCI) underwent neuroimaging for Aβ amyloid., Results: Within the MCI group individuals with high Aβ amyloid showed selective impairment for memory compared with those with low Aβ amyloid; however, this difference was not evident in the healthy group., Conclusions: The current findings provide further evidence of the relationship between Aβ amyloid and cognition, with memory impairment being the primary symptom of the underlying disease during the prodromal phases of AD.

Background: Impaired emotion recognition in dementia is associated with increased patient agitation, behavior management difficulties, and caregiver burden. Emerging evidence supports the presence of very early emotion recognition difficulties in mild cognitive impairment (MCI); however, the relationship between these impairments and psychosocial measures is not yet explored., Methods: Emotion recognition abilities of 27 patients with nonamnestic MCI (naMCI), 29 patients with amnestic MCI (aMCI), and 22 control participants were assessed. Self-report measures assessed patient functional disability, while informants rated the degree of burden they experienced., Results: Difficulties in recognizing anger was evident in the amnestic subtype. Although both the patient groups reported greater social functioning disability, compared with the controls, a relationship between social dysfunction and anger recognition was evident only for patients with naMCI. A significant association was found between burden and anger recognition in patients with aMCI., Conclusions: Impaired emotion recognition abilities impact MCI subtypes differentially. Interventions targeted at patients with MCI, and caregivers are warranted.

Emotion recognition is impaired in dementia and there is some initial evidence to suggest that milder deficits may be present in Mild Cognitive Impairment (MCI) patients, an "at risk" population for transition to dementia. In this study, we investigated the emotion recognition profile of MCI subgroups. Results show emotion recognition deficits exist for the amnestic subtype with impairment in multiple domains, with an emotion-specific deficit for anger recognition. Impaired emotion recognition in aMCI was independent of patient mood and cognitive deficits. The study is the first to examine the nonamnestic subtype. No emotion recognition deficits were found. This finding is surprising given the association between the nonamnestic subtype and frontal systems dysfunction. Impaired emotion recognition could be related to the selective pathophysiology in neural pathways, particularly the temporal lobe and connected limbic and prefrontal regions, implicated in both aMCI and emotion processing. These findings may have implications for early diagnosis, prognosis, and clinical management.

Individuals who carry the apolipoprotein E ε4 polymorphism have an increased risk of late-onset Alzheimer's disease. However, because possession of the ε4 allele confers an increased risk for the diagnosis of dementia, it has proven problematic in older individuals to dissociate the influence of ε4 on cognitive capacity per se as distinct from its influence on clinical diagnostic status. We report a statistical approach that attempts to partial out the influence of diagnostic group membership (Alzheimer's disease, mild cognitive impairment, healthy control) from the influence of apolipoprotein ε4 genetic status on cognitive functioning. The cognitive phenotype hypothesis predicts that ε4-positive individuals will show cognitive deficits (relative to matched ε4-negative individuals) independent of the development of Alzheimer's disease. By contrast, the prodromal/preclinical Alzheimer's disease hypothesis proposes that the effect of apolipoprotein E status on cognitive performance is a function of the increased risk of dementia in individuals with the ε4 allele. We evaluated these hypotheses in the Australian Imaging, Biomarkers and Lifestyle cohort (n = 1112). We first determined whether previously reported findings concerning ε4 status and age-related neuropsychological performance could be explained by the inadvertent recruitment of people with mild cognitive impairment into the healthy control group. We then tested each diagnostic group in isolation to identify any neuropsychological patterns that may be attributed to the ε4 allele. Finally, as interactions between the ε4 allele and age have previously been reported in cognitive functioning within healthy elderly populations, we attempted to determine whether the inclusion of mild cognitively impaired individuals in the sample may drive this relationship. An extensive battery of standardized, well-validated neuropsychological tasks was administered to a final sample of 764 healthy control subjects, 131 individuals with mild cognitive impairment and 168 individuals with Alzheimer's disease. The effect of the ε4 allele on cognitive performance was assessed using a statistical mediation analysis and supplemented with Bayesian methods to address a number of the limitations associated with Fisherian/Neyman-Pearsonian significance testing. Our findings support the prodromal/preclinical Alzheimer's disease hypothesis and do not support the concept of a distinctive ε4-related cognitive phenotype.

Background: It has been proposed that only mild cognitive impairment (MCI) with high Aβ amyloid is indicative of incipient Alzheimer's disease (AD), yet MCI with low Aβ amyloid may reflect other neurodegenerative processes. We aimed to determine the extent to which high Aβ amyloid influenced cognitive function in healthy older adults and adults with MCI., Method: Healthy controls (HC; n = 178) and adults with MCI (n = 56) enrolled in the Australian Imaging, Biomarkers, and Lifestyle study, underwent positron emission tomography neuroimaging for Aβ amyloid and completed an extensive neuropsychological battery, assessing the cognitive domains of verbal and visual episodic memory, executive function, visuoconstruction, attention and processing speed, and language at baseline., Results: MCI with low Aβ performed worse than MCI with high Aβ on measures of executive function, attention, visuoconstruction and language. No differences were observed between HC high and low Aβ groups. When compared with HC with low Aβ, both MCI high and low Aβ groups performed worse on measures of episodic memory. However, only the MCI low Aβ group performed worse than HC low Aβ on measures of executive function, attention, visuoconstruction, and language., Conclusions: When compared with HC with low Aβ amyloid, MCI with high Aβ amyloid present with impairments restricted to episodic memory, and the episodic memory impairments in MCI with low Aβ amyloid were accompanied by impairments in executive function, attention, visuoconstruction, and language, suggesting that MCI with high Aβ amyloid reflects prodromal AD, although further longitudinal data is required to confirm this.

We aimed to characterize the nature and magnitude of cognitive decline in a group of adults with amnestic mild cognitive impairment (aMCI) with high and low levels of amyloid-β (Aβ) in relation to healthy older adults with low Aβ levels. Healthy older adults and adults with aMCI enrolled in the Australian Imaging, Biomarker, and Lifestyle study, completed the CogState brief battery at baseline and 18 months, and underwent positron emission tomography neuroimaging for Aβ at baseline. In this study, we included adults with MCI who had been classified as having high and low levels of Aβ and healthy older adults who had been classified as having low levels of Aβ. Linear model analyses adjusted for baseline cognitive function indicated that relative to healthy older adults with low Aβ, adults with aMCI and high Aβ showed greater decline in working memory and in verbal and visual episodic memory at 18 months. Adults with aMCI and low Aβ also showed greater decline in working memory; however they did not evidence any decline in episodic memory at 18 months. The results of our study suggests that relative to healthy older adults and adults with aMCI with low Aβ, adults with aMCI and high levels of Aβ showed faster rates of decline on measures of episodic memory over 18 months, and this was approximately twice that observed previously for healthy older adults with high Aβ levels.

The aim of this study was to validate the CogState Brief Battery, which assesses psychomotor, attentional, working memory, and visual learning functions, in healthy older people and in patients with mild cognitive impairment (MCI) and Alzheimer's disease (AD), enrolled in the Australian Imaging, Biomarkers and Lifestyle (AIBL) study. In healthy older adults, weak relationships between demographic variables (e.g., education, depression) and cognitive performance were observed. In AD and MCI groups, the magnitude of impairment was greatest for tasks of working memory and memory, with a negative influence of apolipoprotein E ϵ4 status on learning but not working memory. These results suggest that the CogState Brief Battery can be used to screen for AD-related cognitive changes.

Background: Olfactory dysfunction is present in early Alzheimer's disease (AD), and has now been reported in people with amnestic mild cognitive impairment (aMCI). Recent evidence suggests that unawareness of an olfactory deficit may predict which MCI patients will subsequently meet AD criteria. However, important methodological limitations challenge this suggestion. While addressing some of the limitations of previous research, this preliminary study explores unawareness of olfactory deficits as a predictive factor of future AD among people with aMCI., Methods: Twenty-five participants with aMCI, 25 AD patients, and 22 healthy elderly participants underwent testing of olfactory identification. Subjective reports regarding perceived decline in olfactory detection and olfactory identification were also obtained. A subset of participants was reassessed 12 months later., Results: Control participants performed better than both aMCI and AD patients on olfactory identification. Almost uniformly, participants did not report decline in either olfactory detection or identification. Prediction of olfactory identification scores from subjective reports of olfactory function was poor, and awareness of olfactory decline bore no relationship to the likelihood of aMCI patients progressing to AD by the 12-month review., Conclusions: Treating awareness of olfactory function as a unitary construct can be misleading, and there is a poor relationship between subjective and objective measures of olfactory ability. Our preliminary data suggest that unawareness of olfactory decline does not improve the identification of patients with MCI who are more likely to be in the prodromal phase of AD. Replication in a larger cohort is needed to support these findings.

Background: While dysfunction in emotion recognition is sometimes apparent with aging, and is frequently evident in Alzheimer's disease, it is unclear whether individuals who have a high risk of developing dementia exhibit demonstrable changes., Method: A review of the literature pertaining to mild cognitive impairment was undertaken to discern the extent to which emotion recognition deficits are evident in this prodromal period., Results: A search of Medline, Psycinfo and Psyextra databases using specific key words identified only six relevant studies. These studies suggest that the ability to accurately identify facial expressions of affect is compromised., Conclusions: Research in this area is in its infancy. Suggestions are made for furthering our knowledge about this important ability which affects interpersonal relationships, daily functioning, mental well-being and quality of life., (Copyright © 2012 S. Karger AG, Basel.)

To improve understanding of Alzheimer's disease, large observational studies are needed to increase power for more nuanced analyses. Combining data across existing observational studies represents one solution. However, the disparity of such datasets makes this a non-trivial task. Here, a machine learning approach was applied to impute longitudinal neuropsychological test scores across two observational studies, namely the Australian Imaging, Biomarkers and Lifestyle Study (AIBL) and the Alzheimer's Disease Neuroimaging Initiative (ADNI) providing an overall harmonised dataset. MissForest, a machine learning algorithm, capitalises on the underlying structure and relationships of data to impute test scores not measured in one study aligning it to the other study. Results demonstrated that simulated missing values from one dataset could be accurately imputed, and that imputation of actual missing data in one dataset showed comparable discrimination (p