Accelerometer-Derived Relative Amplitude and Midlife Cognition: A Cross-Sectional Study
- 1Northwestern University Feinberg School of Medicine
Abstract
ImportanceLower relative amplitude of the rest-activity pattern has been associated with cognitive decline and incident dementia in older adults, but its relationship with domain-specific cognitive performance during midlife is less well characterized.
ObjectiveTo examine cross-sectional associations between accelerometer-derived relative amplitude and fluid and crystallized cognitive performance among midlife adults.
Design, Setting, and ParticipantsCross-sectional analysis of 851 adults aged 35-64 years enrolled in the MidCog Study and recruited from 13 primary care clinics, including academic practices and federally qualified health centers. Participants completed a 14-day wrist accelerometer recording and the NIH Toolbox Cognition Battery.
ExposureAccelerometer-derived relative amplitude, calculated from the contrast between activity during the most active consecutive 10-hour period and the least active consecutive 5-hour period.
Main Outcomes and MeasuresAge-and education-adjusted NIH Toolbox T-scores (normative mean = 50, SD = 10) for the Fluid Cognition Composite; attention, executive function, episodic memory, working memory, and processing speed; the Crystallized Cognition Composite; receptive language and expressive language. Multivariable linear regression models sequentially adjusted for sociodemographic characteristics, other rest-activity rhythm metrics, established dementia risk factors, average activity, time in bed, and sleep efficiency.
ResultsIn the final adjusted model, each 1-SD lower relative amplitude was associated with a 2.27-point lower Fluid Cognition Composite T-score (95% CI, 1.15-3.40). Lower relative amplitude was also associated with lower attention by 2.74 points (95% CI, 1.49-4.00), executive function by 1.49 points (95% CI, 0.51-2.47), episodic memory by 2.03 points (95% CI, 0.81-3.25), and processing speed by 1.56 points (95% CI, 0.49-2.64). Relative amplitude was not associated with working memory or crystallized cognitive outcomes.
Conclusions and RelevanceAmong midlife adults recruited from primary care practices, lower relative amplitude was associated with modestly poorer fluid cognitive performance after adjustment for established dementia risk factors and sleep characteristics. Relative amplitude may represent a scalable behavioral correlate of cognitive variability within the normative range. Longitudinal studies beginning in midlife are needed to establish temporality, predictive value, or modifiability.
Key PointsO_ST_ABSQuestionC_ST_ABSAmong midlife adults, is lower accelerometer-derived relative amplitude associated with poorer cognitive performance?
FindingsIn this cross-sectional study of 851 adults aged 35-64 years recruited from primary care practices, each 1-SD lower relative amplitude was associated with a 2.27-point (0.23 SD) lower Fluid Cognition Composite T-score. Lower relative amplitude was also associated with poorer attention, executive function, episodic memory, and processing speed, but not working memory or crystallized cognition.
MeaningRelative amplitude may provide a scalable behavioral correlate of variation in fluid cognitive performance during midlife. Longitudinal studies are needed to determine whether it predicts subsequent cognitive decline.
Related
- Wrist-worn accelerometer-derived activity fragmentation and cause-specific mortality in US adults: a population-based prospective cohort study
- Accelerometer-Derived Rest–Activity Rhythms and Sleep Disturbance in Older Adults: A Three-Wave Longitudinal Study
- Accelerometer-derived ‘weekend warrior’ physical activity, genetic susceptibility, and the associated risk of osteoarthritis
- Accelerometer-derived moderate-to-vigorous-intensity physical activity: sex differences in health benefits and health equivalence between the sexes: a prospective cohort study
- Sociodemographic and lifestyle correlates of accelerometer-measured 24-hour physical behavior patterns: a cross-sectional analysis of the ELSA-Brasil cohort Correlatos sociodemográficos e de estilo de vida dos comportamentos de movimento de 24 horas medidos por acelerômetro: uma análise transversal da coorte ELSA-Brasil Correlatos sociodemográficos y del estilo de vida de los patrones de comportamiento físico de 24 horas medidos mediante acelerometría: un análisis transversal de la cohorte ELSA-Brasil
BibTeX
@misc{kim2026accelerometerderived,
title = {{Accelerometer-Derived Relative Amplitude and Midlife Cognition: A Cross-Sectional Study}},
author = {M. Kim and M. Bonham and F. Yeh and M. Arredondo and L. Opsasnick and L. Curtis and S. C. Bailey and J. Y. Benavente and E. H. Ho and P. Chung and D. Wallace and M. Kwasny and J. A. Linder and M. S. Wolf and P. C. Zee},
howpublished = {medRxiv},
year = {2026},
month = sep,
doi = {10.64898/2026.09.15.26361208},
url = {https://www.medrxiv.org/content/10.64898/2026.09.15.26361208v1},
note = {CC BY-NC-ND},
}
RIS
TY - UNPB
TI - Accelerometer-Derived Relative Amplitude and Midlife Cognition: A Cross-Sectional Study
AU - M. Kim
AU - M. Bonham
AU - F. Yeh
AU - M. Arredondo
AU - L. Opsasnick
AU - L. Curtis
AU - S. C. Bailey
AU - J. Y. Benavente
AU - E. H. Ho
AU - P. Chung
AU - D. Wallace
AU - M. Kwasny
AU - J. A. Linder
AU - M. S. Wolf
AU - P. C. Zee
PY - 2026
DA - 2026/09/15
PB - medRxiv
DO - 10.64898/2026.09.15.26361208
UR - https://www.medrxiv.org/content/10.64898/2026.09.15.26361208v1
AB - ImportanceLower relative amplitude of the rest-activity pattern has been associated with cognitive decline and incident dementia in older adults, but its relationship with domain-specific cognitive performance during midlife is less well characterized. ObjectiveTo examine cross-sectional associations between accelerometer-derived relative amplitude and fluid and crystallized cognitive performance among midlife adults. Design, Setting, and ParticipantsCross-sectional analysis of 851 adults aged 35-64 years enrolled in the MidCog Study and recruited from 13 primary care clinics, including academic practices and federally qualified health centers. Participants completed a 14-day wrist accelerometer recording and the NIH Toolbox Cognition Battery. ExposureAccelerometer-derived relative amplitude, calculated from the contrast between activity during the most active consecutive 10-hour period and the least active consecutive 5-hour period. Main Outcomes and MeasuresAge-and education-adjusted NIH Toolbox T-scores (normative mean = 50, SD = 10) for the Fluid Cognition Composite; attention, executive function, episodic memory, working memory, and processing speed; the Crystallized Cognition Composite; receptive language and expressive language. Multivariable linear regression models sequentially adjusted for sociodemographic characteristics, other rest-activity rhythm metrics, established dementia risk factors, average activity, time in bed, and sleep efficiency. ResultsIn the final adjusted model, each 1-SD lower relative amplitude was associated with a 2.27-point lower Fluid Cognition Composite T-score (95% CI, 1.15-3.40). Lower relative amplitude was also associated with lower attention by 2.74 points (95% CI, 1.49-4.00), executive function by 1.49 points (95% CI, 0.51-2.47), episodic memory by 2.03 points (95% CI, 0.81-3.25), and processing speed by 1.56 points (95% CI, 0.49-2.64). Relative amplitude was not associated with working memory or crystallized cognitive outcomes. Conclusions and RelevanceAmong midlife adults recruited from primary care practices, lower relative amplitude was associated with modestly poorer fluid cognitive performance after adjustment for established dementia risk factors and sleep characteristics. Relative amplitude may represent a scalable behavioral correlate of cognitive variability within the normative range. Longitudinal studies beginning in midlife are needed to establish temporality, predictive value, or modifiability. Key PointsO_ST_ABSQuestionC_ST_ABSAmong midlife adults, is lower accelerometer-derived relative amplitude associated with poorer cognitive performance? FindingsIn this cross-sectional study of 851 adults aged 35-64 years recruited from primary care practices, each 1-SD lower relative amplitude was associated with a 2.27-point (0.23 SD) lower Fluid Cognition Composite T-score. Lower relative amplitude was also associated with poorer attention, executive function, episodic memory, and processing speed, but not working memory or crystallized cognition. MeaningRelative amplitude may provide a scalable behavioral correlate of variation in fluid cognitive performance during midlife. Longitudinal studies are needed to determine whether it predicts subsequent cognitive decline.
ER -