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Royall DR, Palmer RF. INFLAMMATION's cognitive impact revealed by a novel "Line of Identity" approach. PLoS One 2024; 19:e0295386. [PMID: 38517924 PMCID: PMC10959355 DOI: 10.1371/journal.pone.0295386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Accepted: 11/22/2023] [Indexed: 03/24/2024] Open
Abstract
IMPORTANCE Dementia is an "overdetermined" syndrome. Few individuals are demented by any single biomarker, while several may independently explain small fractions of dementia severity. It may be advantageous to identify individuals afflicted by a specific biomarker to guide individualized treatment. OBJECTIVE We aim to validate a psychometric classifier to identify persons adversely impacted by inflammation and replicate it in a second cohort. DESIGN Secondary analyses of data collected by the Texas Alzheimer's Research and Care Consortium (TARCC) (N = 3497) and the Alzheimer's Disease Neuroimaging Initiative (ADNI) (N = 1737). SETTING Two large, well-characterized multi-center convenience samples. PARTICIPANTS Volunteers with normal cognition (NC), Mild Cognitive Impairment (MCI) or clinical "Alzheimer's Disease (AD)". EXPOSURE Participants were assigned to "Afflicted" or "Resilient" classes on the basis of a psychometric classifier derived by confirmatory factor analysis. MAIN OUTCOME(S) AND MEASURE(S) The groups were contrasted on multiple assessments and biomarkers. The groups were also contrasted regarding 4-year prospective conversions to "AD" from non-demented baseline diagnoses (controls and MCI). The Afflicted groups were predicted to have adverse levels of inflammation-related blood-based biomarkers, greater dementia severity and greater risk of prospective conversion. RESULTS In ADNI /plasma, 47.1% of subjects were assigned to the Afflicted class. 44.6% of TARCC's subjects were afflicted, 49.5% of non-Hispanic Whites (NHW) and 37.2% of Mexican Americans (MA). There was greater dementia severity in the Afflicted class [by ANOVA: ADNI /F(1) = 686.99, p <0.001; TARCC /F(1) = 1544.01, p <0.001]. "INFLAMMATION" factor composite scores were significantly higher (adverse) in Afflicted subjects [by ANOVA in ADNI /plasma F(1) = 1642.64, p <0.001 and in TARCC /serum F(1) = 3059.96, p <0.001]. Afflicted cases were more likely to convert to AD in the next four years [by Cox's F, ADNI /plasma: F (252, 268) = 3.74 p < 0.001; TARCC /serum: F (160, 134) = 3.03, p < 0.001 (in TARCC's entire sample), F (110, 90) = 4.92, p <0.001 in NHW, and F(50, 44) = 2.13, p = 0.006 in MA]. The proportions converting were similar among afflicted NHW in both cohorts /biofluids but MA exhibited a lower risk (7% in TARCC /serum at 48 months). CONCLUSIONS AND RELEVANCE Our inflammation-specific psychometric classifier selects individuals with pre-specified biomarker profiles and predicts conversion to "AD" across cohorts, biofluids, and ethnicities. This algorithm might be applied to any dementia-related biomarker making the psychometric estimation of individual biomarker effects feasible without biomarker assessment. Our approach also distinguishes individuals resilient to individual biomarker effects allowing for more accurate prediction and precision intervention.
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Affiliation(s)
- Donald R. Royall
- Department of Psychiatry and Behavioral Science, The University of Texas Health Science Center, San Antonio, Texas, United States of America
- Department of Medicine, The University of Texas Health Science Center, San Antonio, Texas, United States of America
- Department of Family and Community Medicine, The University of Texas Health Science Center, San Antonio, Texas, United States of America
- The Glenn Biggs Institute for Alzheimer’s and Neurodegenerative Disease, The University of Texas Health Science Center, San Antonio, Texas, United States of America
| | - Raymond F. Palmer
- Department of Family and Community Medicine, The University of Texas Health Science Center, San Antonio, Texas, United States of America
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Royall DR, Palmer RF. Statin use moderates APOE's and CRP's associations with dementia and is associated with lesser dementia severity in ε4 carriers. Alzheimers Dement 2024; 20:1627-1636. [PMID: 38055626 PMCID: PMC10984456 DOI: 10.1002/alz.13543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 09/21/2023] [Accepted: 10/01/2023] [Indexed: 12/08/2023]
Abstract
INTRODUCTION We tested the effect of statins on C-reactive protein (CRP) and apolipoprotein E (APOE)'s associations with dementia severity. METHODS A total of 1725 participants of the Alzheimer's Disease Neuroimaging Initiative (ADNI) were assigned from 12-month follow-up data into the following groups: (1) ε4 (-)/statin (-), (2) ε4 (-)/statin (+), (3) ε4 (+)/statin (-), and (4) ε4 (+)/statin (+). Dementia severity was assessed by a δ homolog: "dHABS." A mediation model was stratified on statin use and moderation effects tested by a chi-square difference. RESULTS Plasma CRP level decreased with ε4 allelic dose. Statins had no effect on the dHABS d-score in non-carriers but were associated with better scores in carriers. Treated carriers did not have more severe dementia than non-carriers. Statin use moderated the mutual adjusted effects of APOE and CRP. CRP was not a mediator of APOE's effect. DISCUSSION Statins may provide a protective effect on the dementia severity of ε4 carriers. HIGHLIGHTS δ is a dementia-specific phenotype related to general intelligence "g" and is assessed via a "d-score." Apolipoprotein E (APOE) and plasma C-reactive protein (CRP) are independently associated with δ. Plasma CRP decreases with ε4 allelic dose. Statins were associated with better (less demented) d-scores in ε4 carriers but had no effect in non-ε4 carriers. Treated ε4 carriers did not have more severe dementia than non-carriers. Statin use moderated the effects of APOE and CRP on δ. CRP was not a mediator of APOE's effect on δ.
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Affiliation(s)
- Donald R. Royall
- Department of PsychiatryUniversity of Texas Health Science CenterSan AntonioTexasUSA
- Department of MedicineUniversity of Texas Health Science CenterSan AntonioTexasUSA
- Department of Family and Community MedicineUniversity of Texas Health Science CenterSan AntonioTexasUSA
- Glenn Biggs Institute for Alzheimer's and Neurodegenerative DisordersSan AntonioUSA
| | - Raymond F. Palmer
- Department of Family and Community MedicineUniversity of Texas Health Science CenterSan AntonioTexasUSA
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Royall DR, Palmer RF. The effects of CNS atrophy and ICVD on tests of executive function and functional status are mediated by intelligence. CEREBRAL CIRCULATION - COGNITION AND BEHAVIOR 2023; 5:100184. [PMID: 37811522 PMCID: PMC10550593 DOI: 10.1016/j.cccb.2023.100184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 09/05/2023] [Accepted: 09/13/2023] [Indexed: 10/10/2023]
Abstract
Background Impairments in executive function (EF) are often attributed to ischemic cerebrovascular disease (ICVD) and frontal circuit pathology. However, EF can be distinguished from general intelligence and the latter is likely to manifest in "executive" measures. We aimed to distinguish the effects of imaging biomarkers on these constructs. Methods We tested neuroimaging biomarkers as independent predictors of observed 12 month-prospective cognitive performance by a Multiple Indicators Multiple Causes (MIMIC) model in the Alzheimer's Disease Neuroimaging Initiative (ADNI) (N ≅ 1750). Results ICVD was associated with ''Organization" (ORG) and "Planning" (PLAN) domain scores from the test of Every Day Cognition. Left anterior cingulate (LAC) atrophy was independently associated with Trail-Making part B and Animal Naming. The MIMIC model had excellent fit and tests additional latent variables i.e., EF and dEF (a latent δ homolog derived from Spearman's general intelligence factor, g). Only dEF was associated with instrumental activities of daily living (IADL). ICVD and LAC were both associated with observed executive measures through dEF. ICVD was independently associated with those same measures through EF. Conclusions Observed EF is independently determined by multiple factors. The effects of EF-associated MRI biomarkers can be related to disability and dementia only via their effects on g. Because g /δ are unlikely to be located within the frontal lobes, the dementia-specific variance in executive measures may have little to do with either frontal structure or function. Conversely, domain-specific variance in EF may have little to do with either IADL-impairment or dementia.
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Affiliation(s)
- Donald R. Royall
- Department of Psychiatry, the University of Texas Health Science Center, San Antonio, TX, United States of America
- Department of Medicine, the University of Texas Health Science Center, San Antonio, TX, United States of America
- Department of Family and Community Medicine, the University of Texas Health Science Center, San Antonio, TX, United States of America
- The Glenn Biggs Institute for Alzheimer's and Neurodegenerative Disease, the University of Texas Health Science Center, San Antonio, TX, United States of America
| | - Raymond F. Palmer
- Department of Family and Community Medicine, the University of Texas Health Science Center, San Antonio, TX, United States of America
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Salvadori E. Intelligence, cognition, and major neurocognitive disorders: From constructs to measures. CEREBRAL CIRCULATION - COGNITION AND BEHAVIOR 2023; 5:100185. [PMID: 37736144 PMCID: PMC10510085 DOI: 10.1016/j.cccb.2023.100185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 08/15/2023] [Accepted: 09/13/2023] [Indexed: 09/23/2023]
Abstract
The study of intelligence's role in development of major neurocognitive disorders (MND) is influenced by the approaches used to conceptualize and measure these constructs. In the field of cognitive impairment, the use of single 'intelligence' tests is a common approach to estimate intelligence. Despite being a practical compromise between feasibility and constructs, variance of these tests is only partially explained by general intelligence, and some tools (e.g., lexical tasks for premorbid intelligence) presented inherent limitations. Alternatively, factorial models allow an actual measure of intelligence as a latent factor superintending all mental abilities. Royall and colleagues used structural equation modeling to decompose the Spearman's general intelligence factor g in δ (shared variance across cognitive and functional measures) and g' (shared variance across cognitive measures only). Authors defined δ as the 'cognitive correlates of functional status', and thus a 'phenotype for all cause dementia'. Compared to g', δ explained a little rate of cognitive measures' variance, but it demonstrated a higher accuracy in dementia case-finding. From the methodological perspective, given g 'indifference' to its indicators, further studies are needed to identify the minimal set of tools necessary to extract g, and to test also non-cognitive variables as measures of δ. From the clinical perspective, general intelligence seems to influence MND presence and severity more than domain specific cognitive abilities. Giving δ 'blindness' to etiology, its association with biomarkers and contribution to differential diagnosis might be limited. Classical neuropsychological approaches based on patterns of performances at cognitive tests remained fundamental for differential diagnosis.
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Affiliation(s)
- Emilia Salvadori
- Department of Biomedical and Clinical Sciences, University of Milan, Milan 20157, Italy
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Lee J, Ganguli M, Weerman A, Chien S, Lee DY, Varghese M, Dey AB. Online Clinical Consensus Diagnosis of Dementia: Development and Validation. J Am Geriatr Soc 2021; 68 Suppl 3:S54-S59. [PMID: 32815604 DOI: 10.1111/jgs.16736] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 12/19/2019] [Accepted: 01/23/2020] [Indexed: 11/29/2022]
Abstract
OBJECTIVES To introduce cost-effective expert clinical diagnoses of dementia into population-based research using an online platform and to demonstrate their validity against in-person clinical assessment and diagnosis. DESIGN The online platform provides standardized data necessary for clinicians to rate participants on the Clinical Dementia Rating (CDR® ). Using this platform, clinicians diagnosed 60 patients at a range of CDR levels at two clinical sites. The online consensus diagnosis was compared with in-person clinical consensus diagnosis. SETTING All India Institute of Medical Sciences (AIIMS), Delhi, and National Institute of Mental Health and Neurosciences (NIMHANS), Bengaluru, India. PARTICIPANTS Thirty patients each at AIIMS and NIMHANS with equal numbers of patients previously independently rated in person by experts as CDR is 0 (cognitively normal), CDR is 0.5 (mild cognitive impairment), and CDR is 1 or greater (dementia). MEASUREMENTS Multiple clinicians independently rate each participant on each CDR domain using standardized data and expert clinical judgment. The overall summary CDR is calculated by algorithm. When there are discrepancies among clinician ratings, clinicians discuss the case through a virtual consensus conference and arrive at a consensus overall rating. RESULTS Online clinical consensus diagnosis based on standardized interview data provides consistent clinical diagnosis with in-person clinical assessment and consensus diagnosis (κ coefficient = 0.76). CONCLUSION A web-based clinical consensus platform built on the Harmonized Diagnostic Assessment of Dementia for the Longitudinal Aging Study in India interview data is a cost-effective way to obtain reliable expert clinical judgments. A similar approach can be used for other epidemiological studies of dementia. J Am Geriatr Soc 68:S54-S59, 2020.
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Affiliation(s)
- Jinkook Lee
- Center for Economic and Social Research, University of Southern California, Los Angeles, California, USA.,Department of Economics, University of Southern California, and RAND Corporation, Santa Monica, California, USA
| | - Mary Ganguli
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Albert Weerman
- Center for Economic and Social Research, University of Southern California, Los Angeles, California, USA
| | - Sandy Chien
- Center for Economic and Social Research, University of Southern California, Los Angeles, California, USA
| | - Dong Young Lee
- Department of Psychiatry, Seoul National University, Seoul, South Korea
| | - Mathew Varghese
- Department of Psychiatry, National Institute of Mental Health and Neuroscience, Bengaluru, India
| | - Aparajit B Dey
- Department of Geriatric Medicine, All India Institute of Medical Sciences, New Delhi, India
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Porto MF, Benitez-Agudelo JC, Aguirre-Acevedo DC, Barceló-Martinez E, Allegri RF. Diagnostic accuracy of the UDS 3.0 neuropsychological battery in a cohort with Alzheimer's disease in Colombia. APPLIED NEUROPSYCHOLOGY-ADULT 2021; 29:1543-1551. [PMID: 33761292 DOI: 10.1080/23279095.2021.1897007] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
BACKGROUND Alzheimer's disease (AD) is a neurodegenerative disease that causes a gradual loss of cognitive functions and limits daily activities performance. Early diagnosis of AD is essential to start timely treatment. This study aimed to validate the Uniform Data Set neuropsychological battery version 3.0 (UDS 3.0) in a Colombian cohort. METHODS This study is a cross-sectional type, consecutive, incidental, with 143 persons, divided into two groups: 48 diagnosed AD cases and 95 healthy controls, between the ages of 50 and 80+, and between 1 and 19+ years of education. RESULTS The results indicate differences between the control group and the AD group in most battery tests. A significant correlation was found between the Montreal Cognitive Assessment (MoCA), Multilingual Naming Test (MINT), Craft Story, Benson Figure Test, P-word and F-word Phonemic Fluency Test, and their respective reference tests. Cutoff points were found based on the Youden index for each sub-test. The results indicate that all sub-tests are above the reference line of the ROC curve. CONCLUSION The use of the UDS 3.0 in Colombia would help improving clinical diagnostic routes because of its high accuracy and high correlation with tests that measure general impairment; it has good sensitivity and specificity, and it can be a useful tool for AD.
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Affiliation(s)
- Maria F Porto
- Department of Psychology, Universidad de la Costa, Barranquilla, Colombia
| | - Juan Camilo Benitez-Agudelo
- Department of Psychology, Universidad de la Costa, Barranquilla, Colombia.,Research and Development Department, Instituto Colombiano de Neuropedagogía, ICN, Barranquilla, Colombia
| | | | - Ernesto Barceló-Martinez
- Department of Psychology, Universidad de la Costa, Barranquilla, Colombia.,Research and Development Department, Instituto Colombiano de Neuropedagogía, ICN, Barranquilla, Colombia
| | - Ricardo F Allegri
- Department of Psychology, Universidad de la Costa, Barranquilla, Colombia.,Department of Cognitive Neurology, Instituto de Investigaciones Neurológicas FLENI, Buenos Aires, Argentina
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Royall DR, Palmer RF. δ scores predict multiple neuropsychiatric symptoms. Int J Geriatr Psychiatry 2020; 35:1341-1348. [PMID: 32584472 DOI: 10.1002/gps.5371] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 03/03/2020] [Accepted: 06/21/2020] [Indexed: 11/05/2022]
Abstract
OBJECTIVES Dementia severity is strongly related to Spearman's general intelligence factor "g", via the latent dementia phenotype "δ" and is distinct from domain-specific cognitive impairments arising from disease-specific regional pathologies. It is an empiric question whether behavioral and psychological symptoms of dementia (BPSD) are associated with δ or with domain-specific constructs. METHODS A recently developed δ homolog ("dDx") was tested as a predictor of 1 year prospective BPSD in n = 723 Mexican-American and non-Hispanic White participants in the Texas Alzheimer's Research and Care Consortium (TARCC). The informant-rated frequencies of 12 BPSD were rated by the neuropsychiatric inventory (NPI-Q). Baseline BPSD, demographic features, selected biomarkers, and treatment exposure to acetylcholinesterase inhibitors were used as covariates. Composite scores derived from orthogonal latent measures of domain-specific memory (MEM) and executive function (EF) were also tested as predictors. RESULTS "Functionally salient cognitive impairment (FSCI)" that is, categorical "dementia" as diagnosed by dDx was associated with increased prospective frequency of 11/12 BPSD, independently of baseline behavior and covariates. Age, depressive symptoms, and EF were associated with individual BPSD. MEM was not associated with any. Dementia severity, as measured by dDx, was also associated with a prospective increase in total NPI-Q scores. CONCLUSION δ is associated non-specifically with multiple BPSD. This suggests the existence of a dementia-specific behavioral profile, arising from insults to general intelligence, and unrelated to disease-specific regional pathology(ies).
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Affiliation(s)
- Donald R Royall
- Departments of Psychiatry, Medicine, Family and Community Medicine, and the Glenn Biggs Institute for Alzheimer's and Neurodegenerative Disease, The University of Texas Health Science Center, San Antonio, Texas, USA
| | - Raymond F Palmer
- Department of Family and Community Medicine, The University of Texas Health Science Center, San Antonio, Texas, USA
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Royall DR, Palmer RF. δ-Related Biomarkers Attenuate Multiple Alzheimer's Disease Conversion Risks and Offer Targets for Intervention. J Gerontol A Biol Sci Med Sci 2020; 75:2177-2183. [PMID: 31665233 DOI: 10.1093/gerona/glz253] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND We tested certain serum proteins' ability to mediate the effects of demographic variables on prospective 5-year conversion to clinical "Alzheimer's disease" from non-demented states (i.e. normal control and mild cognitive impairment). The proteins were rationally selected from previously published mediators of those same variables' (plural posessive) association with the latent variable "δ," a novel omnibus dementia severity metric. METHODS Each protein's attenuation of its risk factor's independent association with conversion was performed using logistic regression, adjusted for education, ethnicity, self-reported diabetes mellitus, and hypertension, among initially non-demented Mexican American and non-Hispanic white (N = 772) participants in the Texas Alzheimer's Research and Care Consortium. RESULTS A total of 70 (9.1%) non-demented participants at baseline converted to "Alzheimer's disease", with a mean follow-up of 5.4 years. Age >80 years (odds ratio = 3.1), 30-item Geriatric Depression Scale >10/30 (odds ratio = 2.3), female gender (odds ratio = 2.2), and the presence of an apolipoprotein E ε4 allele (odds ratio = 2.4) were independently associated with prospective conversion. These effects were fully attenuated by five serum proteins: age: insulin-like growth factor-binding protein 2 and epidermal growth factor receptor 1; depression: resistin; gender: thrombopoietin; and apolipoprotein E: C-reactive protein. CONCLUSION Clinical dementia arises from the sum of independent δ-related processes. This analysis provides proof of concept for the rational selection of antidementia targets and offers a foundation for precision antidementia therapy.
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Affiliation(s)
- Donald R Royall
- Department of Psychiatry, The University of Texas Health Science Center, San Antonio, Texas
- Department of Medicine, The University of Texas Health Science Center, San Antonio, Texas
- Department of Family and Community Medicine, The University of Texas Health Science Center, San Antonio, Texas
- The Glenn Biggs Institute for Alzheimer's and Neurodegenerative Disease, The University of Texas Health Science Center, San Antonio, Texas
| | - Raymond F Palmer
- Department of Family and Community Medicine, The University of Texas Health Science Center, San Antonio, Texas
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Kenny RA. New Insights and Knowledge on Cognition and Dementia from Population‐Based Cohort of Older Adults in India. J Am Geriatr Soc 2020; 68 Suppl 3:S1-S2. [DOI: 10.1111/jgs.16733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Accepted: 06/24/2020] [Indexed: 11/30/2022]
Affiliation(s)
- Rose Anne Kenny
- Department of Medical GerontologyTrinity College Dublin Ireland
- Mercer's Institute for Successful AgeingSt James Hospital Dublin Ireland
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John SE, Evans SA, Hanfelt J, Loring DW, Goldstein FC. Subjective Memory Complaints in White and African American Participants. J Geriatr Psychiatry Neurol 2020; 33:135-143. [PMID: 31409180 PMCID: PMC7015770 DOI: 10.1177/0891988719868305] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
OBJECTIVE Subjective memory complaints (SMCs) are associated with mild cognitive impairment and dementia but are understudied in African Americans (AAs). We compared SMC endorsement in white and AA participants and evaluated predictors of diagnostic progression. METHODS Initial visit variables, including SMC and memory performance, were compared within a cognitively normal race-matched sample of white and AA participants (Ntotal = 912; 456each race) to assess the presence and predictors of SMC, the predictors of future diagnostic progression, and the change in memory performance over time. RESULTS More white (32.9%) than AA (24.3%) participants reported SMC (P < .01, ϕ = -.10). Subjective memory complaint was predicted by memory performance (B = -0.03, standard error [SE] = 0.013, odds ratio [OR] = .968, P < .05) and race (B = -0.99, SE = 0.080, OR = .373, P < .001). Subjective memory complaints and memory performance were associated with progression, χ2 (3, n = 912) = 102.37, P < .001. African American race (-2.05 ± 0.24 SE) and SMC (-0.45 ± 0.21 SE) were associated with worse memory performance at baseline and over time, χ2(3) = 13.54, P < .01. CONCLUSIONS In contrast to previous research, our study found that SMC is associated with diagnostic progression and objective memory declines in both white and AA participants.
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Affiliation(s)
- Samantha E. John
- Department of Brain Health, University of Nevada, Las Vegas, Las Vegas, NV, USA,Population Health & Health Equity Initiative, University of Nevada, Las Vegas, Las Vegas, NV, USA,Corresponding author. (S.E.J.), 4505 S. Maryland Pkwy, MSM-407, Las Vegas, NV 89154, , Tel: (702) 895-4580
| | - Sarah A. Evans
- Department of Psychology, Marquette University, Milwaukee, WI, USA
| | - John Hanfelt
- Emory Goizueta Alzheimer’s Disease Research Center, Atlanta, GA, USA,Department of Biostatistics and Bioinformatics, Rollins School of Public Health, Emory University, Atlanta, GA, USA
| | - David W. Loring
- Department of Neurology, Emory University School of Medicine, Atlanta, GA, USA
| | - Felicia C. Goldstein
- Emory Goizueta Alzheimer’s Disease Research Center, Atlanta, GA, USA,Department of Neurology, Emory University School of Medicine, Atlanta, GA, USA
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Benavente KSK, Palmer RF, Royall DR. Serum Adiponectin is Related to Dementia. J Gerontol A Biol Sci Med Sci 2020; 75:779-783. [PMID: 31112230 DOI: 10.1093/gerona/glz102] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND The adipokine adiponectin (APN)'s role in Alzheimer's disease (AD) is controversial. Some studies suggest APN is neuroprotective while others propose it has harmful effects. We have used Multiple Indicators Multiple Causes (MIMIC) models to evaluate the effects of serum protein biomarkers on cognitive performance in the Texas Alzheimer's Research and Care Consortium (TARCC) (Royall DR, Bishnoi RJ, Palmer RF. Serum IGF-BP2 strongly moderates age's effect on cognition: a MIMIC analysis. Neurobiol Aging. 2015;36:2232-2240; Bishnoi RJ, Palmer RF, Royall DR. Vitamin D binding protein as a serum biomarker of Alzheimer's disease. J Alzheimers Dis. 2015;43:37-45; Bishnoi RJ, Palmer RF, Royall DR. Serum interleukin (IL)-15 as a biomarker of Alzheimer's disease. PLoS One. 2015;10:e0117282). METHODS MIMIC models were constructed and replicated in randomly selected 50% splits of TARCC's data (Group 1 N = 1,691; Group 2 N = 1,690) and used to evaluate the relationship between serum APN levels and cognition. Our approach has been to divide general intelligence (Spearman's g) (Spearman C. The Abilities of Man: Their Nature and Measurement. 1932) into two latent variables, δ (ie, a dementia-specific phenotype representing the disabling fraction of cognitive variance) and g prime (g') (ie, the residual non-disabling fraction). Only effects on δ are likely to be dementing. RESULTS Serum APN was significantly related to δ scores (r = .10, p = .015). APN had no significant effect on g' (r = -.25, p = .66), nor did it have any independent direct effects on cognitive performance. These results were replicated across random subsets (ΔCHISQ = 2.8(7), p > .90). CONCLUSIONS APN's effect on cognition is mediated through intelligence (ie, δ), likely to be disabling, and therefore to mediate one or more dementing processes. We have previously shown APN to partially mediate age's-specific effect on δ (Royall DR, Al-Rubaye S, Bishnoi R, Palmer RF. Serum protein mediators of dementia and aging proper. Aging (Albany NY). 2016;8:3241-3254). However, because the current model is age adjusted, APN must mediate one or more additional age-independent dementing process(es), possibly AD.
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Affiliation(s)
| | - Raymond F Palmer
- Family and Community Medicine, UT Health San Antonio, San Antonio, Texas
| | - Donald R Royall
- Department of Psychiatry, UT Health San Antonio, San Antonio, Texas
- Family and Community Medicine, UT Health San Antonio, San Antonio, Texas
- Audie L. Murphy Division GRECC, The South Texas Veterans' Health System, San Antonio, Texas
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Royall DR, Bishnoi RJ, Palmer RF. Blood-based protein predictors of dementia severity as measured by δ: Replication across biofluids and cohorts. ALZHEIMER'S & DEMENTIA (AMSTERDAM, NETHERLANDS) 2019; 11:763-774. [PMID: 31909176 PMCID: PMC6939046 DOI: 10.1016/j.dadm.2019.09.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
INTRODUCTION Dementia severity can be empirically described by the latent dementia phenotype "δ" and its various composite "homologs". We have explored δ's blood-based protein biomarkers in the Texas Alzheimer's Research and Care Consortium (TARCC) study. However, it would be convenient to replicate those associations in the Alzheimer's Disease Neuroimaging Initiative (ADNI). To this end, we recently engineered a δ homolog from observed cognitive performance measures common to both projects (i.e., "dT2A"). METHODS We used nine rationally chosen peripheral blood-based protein biomarkers as indicators of a latent variable "INFLAMMATION". We then associated that construct with dT2A in structural equation models adjusted for age, gender, depressive symptoms, and apolipoprotein E (APOE) ε4 allelic burden. Significant factor loadings and INFLAMMATION's association with dT2A were confirmed in random splits of TARCC's relatively large sample, and across biofluids in the ADNI. RESULTS Nine proteins measured in serum (TARCC) or plasma (ADNI) explained ≅10% of dT2A's variance in both samples, independently of age, APOE, education, and gender. All loaded significantly on INFLAMMATION, and positively or negatively, depending on their known roles are PRO- or ANTI-inflammatory proteins, respectively. The parameters of interest were confirmed across random 50% splits of the TARCC's sample, and replicated across biofluids in the ADNI. DISCUSSION These results suggest that SEM can be used to replicate biomarker findings across samples and biofluids, and that a substantial fraction of dementia's variance is attributable to peripheral blood-based protein levels.
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Affiliation(s)
- Donald R. Royall
- Department of Psychiatry, The University of Texas Health Science Center, San Antonio, TX, USA
- Department of Medicine, the University of Texas Health Science Center, San Antonio, TX, USA
- Family and Community Medicine, the University of Texas Health Science Center, San Antonio, TX, USA
- The Biggs Institute for Alzheimer's and Neurodegenerative Disease, the University of Texas Health Science Center, San Antonio, TX, USA
| | - Ram J. Bishnoi
- The Department of Psychiatry, The Medical College of Georgia, Augusta, GA, USA
| | - Raymond F. Palmer
- Family and Community Medicine, the University of Texas Health Science Center, San Antonio, TX, USA
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Royall DR, Palmer RF. Blood-based protein mediators of senility with replications across biofluids and cohorts. Brain Commun 2019; 2:fcz036. [PMID: 32954311 PMCID: PMC7425523 DOI: 10.1093/braincomms/fcz036] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Revised: 09/25/2019] [Accepted: 10/07/2019] [Indexed: 01/08/2023] Open
Abstract
Dementia severity can be quantitatively described by the latent dementia phenotype 'δ' and its various composite 'homologues'. We have explored δ's blood-based protein biomarkers in the Texas Alzheimer's Research and Care Consortium. However, it would be convenient to replicate them in the Alzheimer's Disease Neuroimaging Initiative. To that end, we have engineered a δ homologue from the observed cognitive performance measures common to both projects [i.e. 'd:Texas Alzheimer's Research and Care Consortium to Alzheimer's Disease Neuroimaging Initiative' (dT2A)]. In this analysis, we confirm 13/22 serum proteins as partial mediators of age's effect on dementia severity as measured by dT2A in the Texas Alzheimer's Research and Care Consortium and then replicate 4/13 in the Alzheimer's Disease Neuroimaging Initiative's plasma data. The replicated mediators of age-specific effects on dementia severity are adiponectin, follicle-stimulating hormone, pancreatic polypeptide and resistin. In their aggregate, the 13 confirmed age-specific mediators suggest that 'cognitive frailty' pays a role in dementia severity as measured by δ. We provide both discriminant and concordant support for that hypothesis. Weight, calculated low-density lipoprotein and body mass index are partial mediators of age's effect in the Texas Alzheimer's Research and Care Consortium. Biomarkers related to other disease processes (e.g. cerebrospinal fluid Alzheimer's disease-specific biomarkers in the Alzheimer's Disease Neuroimaging Initiative) are not. It now appears that dementia severity is the sum of multiple independent processes impacting δ. Each may have a unique set of mediating biomarkers. Age's unique effect appears to be at least partially mediated through proteins related to frailty. Age-specific mediation effects can be replicated across cohorts and biofluids. These proteins may offer targets for the remediation of age-specific cognitive decline (aka 'senility'), help distinguish it from other determinants of dementia severity and/or provide clues to the biology of Aging Proper.
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Affiliation(s)
- Donald R Royall
- Department of Psychiatry, The University of Texas Health Science Center, San Antonio, TX 78229-3900, USA
- Department of Medicine, The University of Texas Health Science Center, San Antonio, TX 78229-3900, USA
- Department of Family and Community Medicine, The University of Texas Health Science Center, San Antonio, TX 78229-3900, USA
- The Glenn Biggs Institute for Alzheimer’s & Neurodegenerative Diseases, The University of Texas Health Science Center, San Antonio, TX 78229-3900, USA
| | - Raymond F Palmer
- Department of Family and Community Medicine, The University of Texas Health Science Center, San Antonio, TX 78229-3900, USA
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Royall DR, Palmer RF. Selection for depression-specific dementia cases with replication in two cohorts. PLoS One 2019; 14:e0216413. [PMID: 31150419 PMCID: PMC6544211 DOI: 10.1371/journal.pone.0216413] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Accepted: 04/21/2019] [Indexed: 01/01/2023] Open
Abstract
The latent variable "δ" (for "dementia") provides an etiologically "agnostic" omnibus dementia severity metric capable of recognizing the dementing potential of any condition. Depressive symptoms are independent predictors of δ and are thereby implicated as "dementing". Serum resistin levels partially mediate the association between depressive symptoms and δ. We use a novel "off-diagonal" CHI SQ algorithm to demonstrate our ability to select individuals demented solely by depression's effect in both the Texas Alzheimer's Research and Care Consortium (TARCC) (N ≌ 3,500), and the Alzheimer's Disease Neuroimaging Initiative (ADNI (N ≌ 1,750), and demonstrate the higher resistin levels of such cases in TARCC. This approach can be adapted to any δ-related dementia risk factor or biomarker and used identify individuals who might revert back to non-demented states after its successful treatment.
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Affiliation(s)
- Donald R. Royall
- Department of Psychiatry, the University of Texas Health Science Center, San Antonio, Texas, United States of America
- Department of Medicine, the University of Texas Health Science Center, San Antonio, Texas, United States of America
- Department of Family and Community Medicine, the University of Texas Health Science Center, San Antonio, Texas, United States of America
- South Texas Veterans’ Health System Audie L. Murphy Division Geriatric Research Education and Clinical Care Center, San Antonio, Texas, United States of America
| | - Raymond F. Palmer
- Department of Family and Community Medicine, the University of Texas Health Science Center, San Antonio, Texas, United States of America
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Alzheimer’s Environmental and Genetic Risk Scores are Differentially Associated With General Cognitive Ability and Dementia Severity. Alzheimer Dis Assoc Disord 2019; 33:95-103. [DOI: 10.1097/wad.0000000000000292] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Royall DR, Palmer RF. A δ Homolog for Dementia Case Finding with Replication in the Alzheimer's Disease Neuroimaging Initiative. J Alzheimers Dis 2019; 67:67-79. [PMID: 30507569 DOI: 10.3233/jad-171053] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Dementia can be empirically described by the latent dementia phenotype "δ" and its various composite "homologs". We have explored δ's blood-based protein biomarkers in the Texas Alzheimer's Research and Care Consortium (TARCC) study. However, it would be convenient to replicate those associations in the Alzheimer's Disease Neuroimaging Initiative (ADNI). To this end, we have engineered a δ homolog from observed cognitive performance measures common to both projects. Our findings were replicated in randomly selected 50% splits of TARCC data (Group 1, N = 1,747; Group 2, N = 1,755), and then independently in ADNI (N = 1,737). The new δ homolog, i.e., "dT2A" (d-TARCC to ADNI), fit the data of both studies well, and was strongly correlated with dementia severity, as rated by the Clinical Dementia Rating Scale "sum of boxes" (TARCC: r = 0.99, p < 0.001; ADNI: r = 0.96, p < 0.001). dT2A achieved an area under the receiver operating characteristic curve of 0.981 (0.976-0.985) for the discrimination of Alzheimer's disease from normal controls in TARCC, and 0.988 (0.983-0.993) in ADNI. dT2A is the 12th δ homolog published to date, and opens the door to independent replications across these and similar studies.
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Affiliation(s)
- Donald R Royall
- Department of Psychiatry, The University of Texas Health Science Center, San Antonio, TX, USA
- Department of Medicine, The University of Texas Health Science Center, San Antonio, TX, USA
- Department of Family and Community Medicine, The University of Texas Health Science Center, San Antonio, TX, USA
- South Texas Veterans' Health System Audie L. Murphy Division GRECC, San Antonio, TX, USA
| | - Raymond F Palmer
- Department of Family and Community Medicine, The University of Texas Health Science Center, San Antonio, TX, USA
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Royall DR, Palmer RF. δ Scores Identify Subsets of "Mild Cognitive Impairment" with Variable Conversion Risks. J Alzheimers Dis 2019; 70:199-210. [PMID: 31127788 DOI: 10.3233/jad-190266] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND The latent variable "δ" (for "dementia) is a transdiagnostic measure of dementia severity. δ can be reified and applied to individuals as a composite "d-score". Like Spearman's general intelligence factor "g", δ can be constructed from almost any cognitive battery. So many are available that we must further distinguish each composite as a δ "homolog". Fourteen have been validated. All are strongly associated with dementia severity and potentially with mild cognitive impairment (MCI) conversion. OBJECTIVES To assess δ's impact on MCI conversion risk. METHODS A new δ homolog (dDx) was constructed in 1,230 Mexican-American (MA) and 2,215 non-Hispanic White (NHW) participants in the Texas Alzheimer's Research and Care Consortium (TARCC). 1,445 normal controls (NC) and 723 MCI were followed annually for up to 6 years. RESULTS Each SD decrease in the dDx score increased the risk of conversion sixteen-fold [OR = 16.39 (CI: 5.0-52.6)]. Cases below the optimal diagnostic threshold for Alzheimer's disease (AD) versus NC were labeled as having a functionally salient cognitive impairment (FSCI). Such cases were at a 73-fold increase risk of a diagnosis of AD [OR = 73.19 (95% CI: 58.3-92.0)]. However, 25.6% of MCI cases were also FSCI(+). They accounted disproportionately for prospective conversions. Age <80 years, the absence of an ɛ4 allele, <12 years of education, and MA ethnicity independently increased the risk of diagnosing FSCI as MCI. CONCLUSION A sizable minority of MCI cases may be misdiagnosed and they account disproportionately for AD conversions.
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Affiliation(s)
- Donald R Royall
- Departments of Psychiatry, The University of Texas Health Science Center, San Antonio, TX, USA
- Departments of Medicine, The University of Texas Health Science Center, San Antonio, TX, USA
- Departments of Family and Community Medicine, the University of Texas Health Science Center, San Antonio, TX, USA
- South Texas Veterans' Health System Audie L. Murphy Division GRECC, San Antonio, TX, USA
| | - Raymond F Palmer
- Departments of Family and Community Medicine, the University of Texas Health Science Center, San Antonio, TX, USA
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Royall DR, Al-Rubaye S, Bishnoi R, Palmer RF. Serum proteins mediate depression's association with dementia. PLoS One 2017; 12:e0175790. [PMID: 28594820 PMCID: PMC5464526 DOI: 10.1371/journal.pone.0175790] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Accepted: 03/31/2017] [Indexed: 01/08/2023] Open
Abstract
The latent variable "δ" (for "dementia") uniquely explains dementia severity. Depressive symptoms are independent predictors of δ. We explored 115 serum proteins as potential causal mediators of the effect of depressive symptoms on δ in a large, ethnically diverse, longitudinal cohort. All models were adjusted for age, apolipoprotein E, education, ethnicity, gender, hemoglobin A1c, and homocysteine, and replicated in randomly selected 50% subsets. Alpha1-antitrypsin (A1AT), FAS, Heparin-binding EGF-like Growth Factor (HB-EGF), Insulin-like Growth Factor-1 (IGF-1), Luteinizing Hormone (LH), Macrophage Inflammatory Protein type 1 alpha (MIP-1α), Resitin, S100b, Tissue Inhibitor of Metalloproteinase type 1 (TIMP-1), and Vascular Cell Adhesion Molecule type 1 (VCAM-1) each were partial mediators of depression's association with δ. These proteins may offer targets for the treatment of depression's specific effect on dementia severity and Alzheimer's Disease (AD) conversion risk.
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Affiliation(s)
- Donald R. Royall
- Department of Psychiatry, the University of Texas Health Science Center, San Antonio, Texas, United States of America
- Department of Medicine, the University of Texas Health Science Center, San Antonio, Texas, United States of America
- Department of Family and Community Medicine, the University of Texas Health Science Center, San Antonio, Texas, United States of America
- South Texas Veterans’ Health System Audie L. Murphy Division Geriatric Research Education and Clinical Care Center, San Antonio, Texas, United States of America
| | - Safa Al-Rubaye
- Department of Psychiatry, the University of Texas Health Science Center, San Antonio, Texas, United States of America
| | - Ram Bishnoi
- Department of Psychiatry, the Medical College of Georgia, Augusta, Georgia, United States of America
| | - Raymond F. Palmer
- Department of Family and Community Medicine, the University of Texas Health Science Center, San Antonio, Texas, United States of America
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Royall DR, Palmer RF. δ scores predict mild cognitive impairment and Alzheimer's disease conversions from nondemented states. ALZHEIMER'S & DEMENTIA (AMSTERDAM, NETHERLANDS) 2017; 6:214-221. [PMID: 28378011 PMCID: PMC5369695 DOI: 10.1016/j.dadm.2017.02.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
INTRODUCTION We tested the latent variable "δ" (for "dementia")'s ability to predict conversion to "mild cognitive impairment" (MCI) and Alzheimer's disease (AD). METHODS An ethnicity equivalent d homolog ("dEQ") was constructed in n = 1113 Mexican- American (MA) and n = 1958 non-Hispanic white (NHW) participants in the Texas Alzheimer's Research and Care Consortium. "Normal Controls" (NC) (n = 1276) and MCI cases (n = 611) were followed annually for up to 6 years [m = 4.7(0.6)]. RESULTS 22.0% (n = 281) of NC converted to "MCI" or "AD". 17.3%( n = 106) of MCI converted to "AD." Independently of covariates, each quintile increase in the dEQ scores of NC increased the odds of conversion by 52%. Each quintile increase in the dEQ scores of MCI cases increased the odds of conversion to AD almost three-fold. DISCUSSION Baseline δ scores predict MCI and AD conversions from nondemented states in MA and NHW.
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Affiliation(s)
- Donald R. Royall
- Department of Psychiatry, University of Texas Health Science Center, San Antonio, TX, USA
- Department of Medicine, University of Texas Health Science Center, San Antonio, TX, USA
- Department of Family and Community Medicine, University of Texas Health Science Center, San Antonio, TX, USA
- South Texas Veterans' Health System Audie L. Murphy Division GRECC, San Antonio, TX, USA
| | - Raymond F. Palmer
- Department of Family and Community Medicine, University of Texas Health Science Center, San Antonio, TX, USA
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The Differential Effects of Alzheimer's Disease and Lewy Body Pathology on Cognitive Performance: a Meta-analysis. Neuropsychol Rev 2016; 27:1-17. [PMID: 27878426 DOI: 10.1007/s11065-016-9334-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2016] [Accepted: 09/29/2016] [Indexed: 10/20/2022]
Abstract
Differential diagnosis of Alzheimer's disease (AD) from normal aging and other dementia etiologies is imperative for disease specific treatment options and long-term care planning. Neuropathological confirmation is the gold standard for neurodegenerative disease diagnosis, yet most published studies examining the use of neuropsychological tests in the differential diagnosis of dementia rely upon clinical diagnostic outcomes. The present study undertook a meta-analytic review of the literature to identify cognitive tests and domains that allow for the differentiation of individuals with AD pathology from individuals with dementia with Lewy Bodies (DLB) pathology and pathology-free individuals. A comprehensive literature search yielded 14 studies that met the inclusion criteria for the present meta-analysis. Six studies comprised 222 decedents with AD compared to 433 normal controls, and eight studies comprised 431 cases of AD compared to 155 decedents with DLB. Results revealed that the effect of having neuropathologically confirmed AD versus DLB lowered performance in the memory domain, and having DLB decreased performance in the visuospatial domain. No single test differed significantly across the AD and DLB groups. For the AD and pathology free comparison, results indicated that that AD was associated with poorer performance on the memory and language domains. With respect to specific cognitive tests, AD produced lower scores on list learning tests, category fluency, and the Digit Symbol substitution test. The limited number of studies meeting inclusion criteria warrants formulation of guidelines for reporting in clinico-pathological studies; suggested guidelines are provided.
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