TY - JOUR
T1 - Assessing cognition and daily function in early dementia using the cognitive-functional composite
T2 - Findings from the Catch-Cog study cohort
AU - Jutten, Roos J.
AU - Harrison, John E.
AU - Lee Meeuw Kjoe, Philippe R.
AU - Ingala, Silvia
AU - Vreeswijk, R.
AU - Van Deelen, R. A.J.
AU - De Jong, Frank Jan
AU - Opmeer, Esther M.
AU - Aleman, André
AU - Ritchie, Craig W.
AU - Scheltens, Philip
AU - Sikkes, Sietske A.M.
PY - 2019/5/15
Y1 - 2019/5/15
N2 - Background: The cognitive-functional composite (CFC) was designed to improve the measurement of clinically relevant changes in predementia and early dementia stages. We have previously demonstrated its good test-retest reliability and feasibility of use. The current study aimed to evaluate several quality aspects of the CFC, including construct validity, clinical relevance, and suitability for the target population. Methods: Baseline data of the Capturing Changes in Cognition study was used: an international, prospective cohort study including participants with subjective cognitive decline (SCD), mild cognitive impairment (MCI), Alzheimer's disease (AD) dementia, and dementia with Lewy bodies (DLB). The CFC comprises seven existing cognitive tests focusing on memory and executive functions (EF) and the informant-based Amsterdam Instrumental Activities of Daily Living Questionnaire (A-IADL-Q). Construct validity and clinical relevance were assessed by (1) confirmatory factor analyses (CFA) using all CFC subtests and (2) linear regression analyses relating the CFC score (independent) to reference measures of disease severity (dependent), correcting for age, sex, and education. To assess the suitability for the target population, we compared score distributions of the CFC to those of traditional tests (Alzheimer's Disease Assessment Scale-Cognitive subscale, Alzheimer's Disease Cooperative Study-Activities of Daily Living scale, and Clinical Dementia Rating scale). Results: A total of 184 participants were included (age 71.8 ± 8.4; 42% female; n = 14 SCD, n = 80 MCI, n = 78 AD, and n = 12 DLB). CFA showed that the hypothesized three-factor model (memory, EF, and IADL) had adequate fit (CFI =.931, RMSEA =.091, SRMR =.06). Moreover, worse CFC performance was associated with more cognitive decline as reported by the informant (β =.61, p <.001), poorer quality of life (β =.51, p <.001), higher caregiver burden (β = -.51, p <.001), more apathy (β = -.36, p <.001), and less cortical volume (β =.34, p =.02). Whilst correlations between the CFC and traditional measures were moderate to strong (ranging from -.65 to.83, all p <.001), histograms showed floor and ceiling effects for the traditional tests as compared to the CFC. Conclusions: Our findings illustrate that the CFC has good construct validity, captures clinically relevant aspects of disease severity, and shows no range restrictions in scoring. It therefore provides a more useful outcome measure than traditional tests to evaluate cognition and function in MCI and mild AD.
AB - Background: The cognitive-functional composite (CFC) was designed to improve the measurement of clinically relevant changes in predementia and early dementia stages. We have previously demonstrated its good test-retest reliability and feasibility of use. The current study aimed to evaluate several quality aspects of the CFC, including construct validity, clinical relevance, and suitability for the target population. Methods: Baseline data of the Capturing Changes in Cognition study was used: an international, prospective cohort study including participants with subjective cognitive decline (SCD), mild cognitive impairment (MCI), Alzheimer's disease (AD) dementia, and dementia with Lewy bodies (DLB). The CFC comprises seven existing cognitive tests focusing on memory and executive functions (EF) and the informant-based Amsterdam Instrumental Activities of Daily Living Questionnaire (A-IADL-Q). Construct validity and clinical relevance were assessed by (1) confirmatory factor analyses (CFA) using all CFC subtests and (2) linear regression analyses relating the CFC score (independent) to reference measures of disease severity (dependent), correcting for age, sex, and education. To assess the suitability for the target population, we compared score distributions of the CFC to those of traditional tests (Alzheimer's Disease Assessment Scale-Cognitive subscale, Alzheimer's Disease Cooperative Study-Activities of Daily Living scale, and Clinical Dementia Rating scale). Results: A total of 184 participants were included (age 71.8 ± 8.4; 42% female; n = 14 SCD, n = 80 MCI, n = 78 AD, and n = 12 DLB). CFA showed that the hypothesized three-factor model (memory, EF, and IADL) had adequate fit (CFI =.931, RMSEA =.091, SRMR =.06). Moreover, worse CFC performance was associated with more cognitive decline as reported by the informant (β =.61, p <.001), poorer quality of life (β =.51, p <.001), higher caregiver burden (β = -.51, p <.001), more apathy (β = -.36, p <.001), and less cortical volume (β =.34, p =.02). Whilst correlations between the CFC and traditional measures were moderate to strong (ranging from -.65 to.83, all p <.001), histograms showed floor and ceiling effects for the traditional tests as compared to the CFC. Conclusions: Our findings illustrate that the CFC has good construct validity, captures clinically relevant aspects of disease severity, and shows no range restrictions in scoring. It therefore provides a more useful outcome measure than traditional tests to evaluate cognition and function in MCI and mild AD.
KW - Alzheimer's disease
KW - Cognition
KW - Composite
KW - Construct validation
KW - Daily function
KW - Dementia
KW - Instrumental activities of daily living
KW - Mild cognitive impairment
KW - Outcome measures
UR - http://www.scopus.com/inward/record.url?scp=85066055585&partnerID=8YFLogxK
U2 - 10.1186/s13195-019-0500-5
DO - 10.1186/s13195-019-0500-5
M3 - Article
AN - SCOPUS:85066055585
SN - 1758-9193
VL - 11
JO - Alzheimer's Research and Therapy
JF - Alzheimer's Research and Therapy
IS - 1
M1 - 45
ER -