%0 Journal Article %J J Alzheimers Dis %D 2023 %T Physical Activity for Cognitive Health: A Model for Intervention Design for People Experiencing Cognitive Concerns and Symptoms of Depression or Anxiety. %A Curran, Eleanor %A Palmer, Victoria J %A Ellis, Kathryn A %A Chong, Terence W H %A Rego, Thomas %A Cox, Kay L %A Anstey, Kaarin J %A Westphal, Alissa %A Moorhead, Rebecca %A Southam, Jenny %A Lai, Rhoda %A You, Emily %A Lautenschlager, Nicola T %X

BACKGROUND: People experiencing cognitive concerns and symptoms of depression or anxiety are at risk for Alzheimer's disease and dementia. We know physical activity can benefit cognition but understanding how to best support engagement is an ongoing challenge. Evidence-based conceptual models of factors underpinning physical activity engagement in target populations can inform intervention tailoring to address this challenge.

OBJECTIVE: This study (part of a pragmatic physical activity implementation trial) aimed to develop a specified model of physical activity engagement in people experiencing depressive or anxiety symptoms and cognitive concerns, to enable optimized dementia risk reduction intervention tailoring.

METHODS: We employed a qualitative design, triangulating data from three sources: semi-structured individual interviews with people experiencing cognitive concerns and mild to moderate depressive or anxiety symptoms; review of published evidence; and the Capability, Opportunity and Motivation system of behavior, an existing behavioral science model. Findings were integrated to develop a contextualized model of mechanisms of action for optimizing engagement.

RESULTS: Twenty-one participants were interviewed, and 24 relevant papers included. Convergent and complementary themes extended understanding of intervention needs. Findings highlighted emotional regulation, capacities to enact intentions despite barriers, and confidence in existing skills as areas of population-specific need that have not previously been emphasized. The final model provides specificity, directionality, and linked approaches for intervention tailoring.

CONCLUSION: This study demonstrated that people experiencing cognitive concerns and symptoms of depression or anxiety require different interventions to improve physical activity engagement. The novel model can enable more precise intervention tailoring, and, ultimately, benefits for a key at-risk population.

%B J Alzheimers Dis %V 94 %P 781-799 %8 2023 Jul 18 %G eng %N 2 %R 10.3233/JAD-221216 %0 Journal Article %J J Alzheimers Dis %D 2018 %T Concordance Between Cerebrospinal Fluid Biomarkers with Alzheimer's Disease Pathology Between Three Independent Assay Platforms. %A Doecke, James D %A Rembach, Alan %A Villemagne, Victor L %A Varghese, Shiji %A Rainey-Smith, Stephanie %A Sarros, Shannon %A Evered, Lisbeth A %A Fowler, Christopher J %A Pertile, Kelly K %A Rumble, Rebecca L %A Trounson, Brett %A Taddei, Kevin %A Laws, Simon M %A Macaulay, S Lance %A Bush, Ashley I %A Ellis, Kathryn A %A Martins, Ralph %A Ames, David %A Silbert, Brendan %A Vanderstichele, Hugo %A Masters, Colin L %A Darby, David G %A Li, Qiao-Xin %A Collins, Steven %K Aged %K Aged, 80 and over %K Alzheimer Disease %K Amyloid beta-Peptides %K Biomarkers %K Cognition Disorders %K Female %K Humans %K Male %K Mental Status Schedule %K Peptide Fragments %K Positron-Emission Tomography %K ROC Curve %K tau Proteins %X

BACKGROUND: To enhance the accuracy of clinical diagnosis for Alzheimer's disease (AD), pre-mortem biomarkers have become increasingly important for diagnosis and for participant recruitment in disease-specific treatment trials. Cerebrospinal fluid (CSF) biomarkers provide a low-cost alternative to positron emission tomography (PET) imaging for in vivo quantification of different AD pathological hallmarks in the brains of affected subjects; however, consensus around the best platform, most informative biomarker and correlations across different methodologies are controversial.

OBJECTIVE: Assessing levels of Aβ-amyloid and tau species determined using three different versions of immunoassays, the current study explored the ability of CSF biomarkers to predict PET Aβ-amyloid (32 Aβ-amyloid-and 45 Aβ-amyloid+), as well as concordance between CSF biomarker levels and PET Aβ-amyloid imaging.

METHODS: Prediction and concordance analyses were performed using a sub-cohort of 77 individuals (48 healthy controls, 15 with mild cognitive impairment, and 14 with AD) from the Australian Imaging Biomarker and Lifestyle study of aging.

RESULTS: Across all three platforms, the T-tau/Aβ42 ratio biomarker had modestly higher correlation with SUVR/BeCKeT (ρ= 0.69-0.8) as compared with Aβ42 alone (ρ= 0.66-0.75). Differences in CSF biomarker levels between the PET Aβ-amyloid-and Aβ-amyloid+ groups were strongest for the Aβ42/Aβ40 and T-tau/Aβ42 ratios (p < 0.0001); however, comparison of predictive models for PET Aβ-amyloid showed no difference between Aβ42 alone and the T-tau/Aβ42 ratio.

CONCLUSION: This study confirms strong concordance between CSF biomarkers and PET Aβ-amyloid status is independent of immunoassay platform, supporting their utility as biomarkers in clinical practice for the diagnosis of AD and for participant enrichment in clinical trials.

%B J Alzheimers Dis %V 61 %P 169-183 %8 2018 %G eng %N 1 %1 http://www.ncbi.nlm.nih.gov/pubmed/29171991?dopt=Abstract %R 10.3233/JAD-170128 %0 Journal Article %J J Alzheimers Dis %D 2016 %T Subjective Memory Complaints in APOEɛ4 Carriers are Associated with High Amyloid-β Burden. %A Zwan, Marissa D %A Villemagne, Victor L %A Doré, Vincent %A Buckley, Rachel %A Bourgeat, Pierrick %A Veljanoski, Robyn %A Salvado, Olivier %A Williams, Rob %A Margison, Laura %A Rembach, Alan %A Macaulay, S Lance %A Martins, Ralph %A Ames, David %A van der Flier, Wiesje M %A Ellis, Kathryn A %A Scheltens, Philip %A Masters, Colin L %A Rowe, Christopher C %K Aged %K Aging %K Amyloid beta-Peptides %K Aniline Compounds %K Apolipoprotein E4 %K Benzothiazoles %K Brain %K Cognition Disorders %K Female %K Genotyping Techniques %K Heterozygote %K Humans %K Logistic Models %K Male %K Neuropsychological Tests %K Positron-Emission Tomography %K Radiopharmaceuticals %K Thiazoles %X

BACKGROUND: APOEɛ4 genotype and aging have been identified as risk factors for Alzheimer's disease (AD). In addition, subjective memory complaints (SMC) might be a first clinical expression of the effect of AD pathology on cognitive functioning.

OBJECTIVE: To assess whether APOEɛ4 genotype, age, SMC, and episodic memory are risk factors for high amyloid-β (Aβ) burden in cognitively normal elderly.

METHODS: 307 cognitively normal participants (72.7 ± 6.8 years, 53% female, 55% SMC) from the Australian Imaging, Biomarkers and Lifestyle (AIBL) study underwent amyloid PET and APOE genotyping. Logistic regression analyses were performed to determine the association of APOEɛ4 genotype, age, SMC, and episodic memory with Aβ pathology.

RESULTS: Odds of high Aβ burden were greater at an older age (OR = 3.21; 95% CI = 1.68-6.14), when SMC were present (OR = 1.90; 95% CI = 1.03-3.48), and for APOEɛ4 carriers (OR = 7.49; 95% CI = 3.96-14.15), while episodic memory was not associated with odds of high Aβ burden. Stratified analyses showed that odds of SMC for high Aβ burden were increased in specifically APOEɛ4 carriers (OR = 4.58, 95% CI = 1.83-11.49) and younger participants (OR = 3.73, 95% CI = 1.39-10.01).

CONCLUSION: Aging, APOEɛ4 genotype, and SMC were associated with high Aβ burden. SMC were especially indicative of high Aβ burden in younger participants and in APOEɛ4 carriers. These findings suggest that selection based on the presence of SMC, APOEɛ4 genotype and age may help identify healthy elderly participants with high Aβ burden eligible for secondary prevention trials.

%B J Alzheimers Dis %V 49 %P 1115-22 %8 2016 %G eng %N 4 %1 http://www.ncbi.nlm.nih.gov/pubmed/26639956?dopt=Abstract %R 10.3233/JAD-150446 %0 Journal Article %J J Alzheimers Dis %D 2015 %T Alzheimer's Disease Normative Cerebrospinal Fluid Biomarkers Validated in PET Amyloid-β Characterized Subjects from the Australian Imaging, Biomarkers and Lifestyle (AIBL) study. %A Li, Qiao-Xin %A Villemagne, Victor L %A Doecke, James D %A Rembach, Alan %A Sarros, Shannon %A Varghese, Shiji %A McGlade, Amelia %A Laughton, Katrina M %A Pertile, Kelly K %A Fowler, Christopher J %A Rumble, Rebecca L %A Trounson, Brett O %A Taddei, Kevin %A Rainey-Smith, Stephanie R %A Laws, Simon M %A Robertson, Joanne S %A Evered, Lisbeth A %A Silbert, Brendan %A Ellis, Kathryn A %A Rowe, Christopher C %A Macaulay, S Lance %A Darby, David %A Martins, Ralph N %A Ames, David %A Masters, Colin L %A Collins, Steven %X

BACKGROUND: The cerebrospinal fluid (CSF) amyloid-β (Aβ)1-42, total-tau (T-tau), and phosphorylated-tau (P-tau181P) profile has been established as a valuable biomarker for Alzheimer's disease (AD).

OBJECTIVE: The current study aimed to determine CSF biomarker cut-points using positron emission tomography (PET) Aβ imaging screened subjects from the Australian Imaging, Biomarkers and Lifestyle (AIBL) study of aging, as well as correlate CSF analyte cut-points across a range of PET Aβ amyloid ligands.

METHODS: Aβ pathology was determined by PET imaging, utilizing 11C-Pittsburgh Compound B, 18F-flutemetamol, or 18F-florbetapir, in 157 AIBL participants who also underwent CSF collection. Using an INNOTEST assay, cut-points were established (Aβ1-42 >544 ng/L, T-tau <407 ng/L, and P-tau181P <78 ng/L) employing a rank based method to define a "positive" CSF in the sub-cohort of amyloid-PET negative healthy participants (n = 97), and compared with the presence of PET demonstrated AD pathology.

RESULTS: CSF Aβ1-42 was the strongest individual biomarker, detecting cognitively impaired PET positive mild cognitive impairment (MCI)/AD with 85% sensitivity and 91% specificity. The ratio of P-tau181P or T-tau to Aβ1-42 provided greater accuracy, predicting MCI/AD with Aβ pathology with ≥92% sensitivity and specificity. Cross-validated accuracy, using all three biomarkers or the ratio of P-tau or T-tau to Aβ1-42 to predict MCI/AD, reached ≥92% sensitivity and specificity.

CONCLUSIONS: CSF Aβ1-42 levels and analyte combination ratios demonstrated very high correlation with PET Aβ imaging. Our study offers additional support for CSF biomarkers in the early and accurate detection of AD pathology, including enrichment of patient cohorts for treatment trials even at the pre-symptomatic stage.

%B J Alzheimers Dis %V 48 %P 175-87 %8 2015 Aug 28 %G eng %N 1 %1 http://www.ncbi.nlm.nih.gov/pubmed/26401938?dopt=Abstract %R 10.3233/JAD-150247