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Background: Progressive difficulty in performing everyday functional activities is a key diagnostic feature of dementia syndromes. However, not much is known about the neural signature of functional decline, particularly during the very early stages of dementia. Early intervention before overt impairment is observed offers the best hope of reducing the burdens of Alzheimer disease (AD) and other dementias. However, to justify early intervention, those at risk need to be detected earlier and more accurately. The decline in complex daily function (CdF) such as managing medications has been reported to precede impairment in basic activities of daily living (eg, eating and dressing). Objective: Our goal is to establish the neural signature of decline in CdF during the preclinical dementia period. Methods: Gait is central to many CdF and community-based activities. Hence, to elucidate the neural signature of CdF, we validated a novel electroencephalographic approach to measuring gait-related brain activation while participants perform complex gait-based functional tasks. We hypothesize that dementia-related pathology during the preclinical period activates a unique gait-related electroencephalographic (grEEG) pattern that predicts a subsequent decline in CdF. Results: We provide preliminary findings showing that older adults reporting CdF limitations can be characterized by a unique gait-related neural signature: weaker sensorimotor and stronger motor control activation. This subsample also had smaller brain volume and white matter hyperintensities in regions affected early by dementia and engaged in less physical exercise. We propose a prospective observational cohort study in cognitively unimpaired older adults with and without subclinical AD (plasma amyloid-β) and vascular (white matter hyperintensities) pathologies. We aim to (1) establish the unique grEEG activation as the neural signature and predictor of decline in CdF during the preclinical dementia period; (2) determine associations between dementia-related pathologies and incidence of the neural signature of CdF; and (3) establish associations between a dementia risk factor, physical inactivity, and the neural signature of CdF. Conclusions: By establishing the clinical relevance and biological basis of the neural signature of CdF decline, we aim to improve prediction during the preclinical stages of ADs and other dementias. Our approach has important research and translational implications because grEEG protocols are relatively inexpensive and portable, and predicting CdF decline may have real-world benefits. International Registered Report Identifier (IRRID): DERR1-10.2196/56726 [ABSTRACT FROM AUTHOR]

Introduction: The nature and course of limitations in everyday function in the early clinical stages of cognitive decline is not well known. Methods: We compared complex everyday functional profiles at baseline in 59 community‐dwelling older individuals with normal cognitive performance who went on to develop incident mild cognitive impairment (MCI) ("pre‐MCI") with 284 older individuals who remained cognitively normal over follow‐up. Results: The mean number of limitations on complex everyday function at baseline was 3.1 ± 3.0 in the 59 pre‐MCI cases and 2.0 ± 2.4 in the 284 normal controls (P =.003). Pre‐MCI cases had limitations in traveling, entertaining, remembering appointments, and hobbies compared to normal controls. A progressive increase in mild limitations on complex everyday function preceded the incidence of MCI (mean change: pre‐MCI 1.9 ± 3.6 vs normal controls 0.5 ± 2.7, P <.001). Discussion: Prodromal stages of MCI are associated with progressive mild limitations in complex activities of daily living. [ABSTRACT FROM AUTHOR]

Behavioral findings suggest that aging alters the involvement of cortical sensorimotor mechanisms in postural control. However, corresponding accounts of the underlying neural mechanisms remain sparse, especially the extent to which these mechanisms are affected during more demanding tasks. Here, we set out to elucidate cortical correlates of altered postural stability in younger and older adults. 3D body motion tracking and high‐density electroencephalography (EEG) were measured while 14 young adults (mean age = 24 years, 43% women) and 14 older adults (mean age = 77 years, 50% women) performed a continuous balance task under four different conditions. Manipulations were applied to the base of support (either regular or tandem (heel‐to‐toe) stance) and visual input (either static visual field or dynamic optic flow). Standing in tandem, the more challenging position, resulted in increased sway for both age groups, but for the older adults, only this effect was exacerbated when combined with optic flow compared to the static visual display. These changes in stability were accompanied by neuro‐oscillatory modulations localized to midfrontal and parietal regions. A cluster of electro‐cortical sources localized to the supplementary motor area showed a large increase in theta spectral power (4–7 Hz) during tandem stance, and this modulation was much more pronounced for the younger group. Additionally, the older group displayed widespread mu (8–12 Hz) and beta (13–30 Hz) suppression as balance tasks placed more demands on postural control, especially during tandem stance. These findings may have substantial utility in identifying early cortical correlates of balance impairments in otherwise healthy older adults. [ABSTRACT FROM AUTHOR]

Introduction: The nature and course of limitations in everyday function in the early clinical stages of cognitive decline is not well known., Methods: We compared complex everyday functional profiles at baseline in 59 community-dwelling older individuals with normal cognitive performance who went on to develop incident mild cognitive impairment (MCI) ("pre-MCI") with 284 older individuals who remained cognitively normal over follow-up., Results: The mean number of limitations on complex everyday function at baseline was 3.1 ± 3.0 in the 59 pre-MCI cases and 2.0 ± 2.4 in the 284 normal controls (P = .003). Pre-MCI cases had limitations in traveling, entertaining, remembering appointments, and hobbies compared to normal controls. A progressive increase in mild limitations on complex everyday function preceded the incidence of MCI (mean change: pre-MCI 1.9 ± 3.6 vs normal controls 0.5 ± 2.7, P < .001)., Discussion: Prodromal stages of MCI are associated with progressive mild limitations in complex activities of daily living., (© 2022 the Alzheimer's Association.)

The present study investigated the feasibility of acquiring high-density event-related brain potential (ERP) recordings during treadmill walking in human subjects. The work builds upon recent studies testing the applicability of real-world tasks while obtaining electroencephalographic (EEG) recordings. Participants performed a response inhibition GO/NOGO task - designed to evoke a P3 component for correct response inhibitions and an error-related negativity (ERN) for incorrect commission errors - while speed of walking was experimentally manipulated. Robust P3 and ERN components were obtained under all experimental conditions - while participants were sitting, walking at moderate speed (2.4 km/hour), or walking rapidly (5 km/hour). Signal-to-noise ratios were remarkably similar across conditions, pointing to the feasibility of high-fidelity ERP recordings under relatively vigorous activity regimens. There is considerable research and clinical motivation to obtain high quality neurophysiological measures under more naturalistic environmental settings such as these. Strong links between cognitive load and gait abnormalities are seen in a number of clinical populations and these MoBI technologies provide highly promising methods for gaining insights into the underlying pathophysiology.