A passive and objective measure of recognition memory in Alzheimer’s disease using Fastball memory assessment

Abstract

Earlier diagnosis of Alzheimer’s disease requires biomarkers sensitive to associated structural and functional changes. While considerable progress has been made in the development of structural biomarkers, functional biomarkers of early cognitive change, unconfounded by effort, practice and level of education, are still needed. We present Fastball, a new EEG method for the passive and objective measurement of recognition memory, that requires no behavioural memory response or comprehension of the task . Younger adults, older adults and Alzheimer’s disease patients (n = 20 per group) completed the Fastball task, lasting just under 3 min. Participants passively viewed rapidly presented images and EEG assessed their automatic ability to differentiate between images based on previous exposure, i.e. old/new. Participants were not instructed to attend to previously seen images and provided no behavioural response. Following the Fastball task, participants completed a two-alternative forced choice (2AFC) task to measure their explicit behavioural recognition of previously seen stimuli. Fastball EEG detected significantly impaired recognition memory in Alzheimer’s disease compared to healthy older adults (P < 0.001, Cohen’s d = 1.52), whereas behavioural recognition was not significantly different between Alzheimer’s disease and healthy older adults. Alzheimer’s disease patients could be discriminated with high accuracy from healthy older adult controls using the Fastball measure of recognition memory (AUC = 0.86, P < 0.001), whereas discrimination performance was poor using behavioural 2AFC accuracy (AUC = 0.63, P = 0.148). There were no significant effects of healthy ageing, with older and younger adult controls performing equivalently in both the Fastball task and behavioural 2AFC task. Early diagnosis of Alzheimer’s disease offers potential for early treatment when quality of life and independence can be retained through disease modification and cognitive enhancement. Fastball provides an alternative way of testing recognition responses that holds promise as a functional marker of disease pathology in stages where behavioural performance deficits are not yet evident. It is passive, non-invasive, quick to administer and uses cheap, scalable EEG technology. Fastball provides a new powerful method for the assessment of cognition in dementia and opens a new door in the development of early diagnosis tools.

A neural marker of the human face identity familiarity effect

“…Moreover, while we ensured that (un)familiar faces were (un)familiar for every participant, the familiarity contrast could have even been stronger overall and strengthened by independent behavioral measures (see methods and discussion above). This high sensitivity coupled with the high specificity (i.e., no hint of a neural FIFE in the case of prosopdysgnosia JG, in line with behavioral data) and the focal localization of the effect in all individuals (i.e., allowing to use a small number of recording channels) makes this paradigm highly desirable for implicit evaluation of human face identity knowledge in individual participants, with practical implications in clinical (i.e., as biomarkers of neurodevelopmental or neurodegenerative disorders in face identity recognition, e.g., Autism Spectrum Disorder or Alzheimer’s disease 83 , 84 ) and forensic research for instance 85 . In this vein, providing that the stimulus set remains large and is adequately adjusted to new populations, future studies could build on the present paradigm to evaluate (1) the relationship between the magnitude of the neural FIFE and the degree of familiarity with the faces (i.e., beyond a simple contrast between familiar and unfamiliar faces) and (2) its sensitivity to personally familiar and/or familiarized (learned) face identities on an individual basis.…”

From Gut Microbiota to Brain Waves: The Potential of the Microbiome and EEG as Biomarkers for Cognitive Impairment

“…A recent study by Traikapi and Konstantinou (2021) found disruptions in the gamma waves in AD patients and discovered that gamma stimulation could potentially reduce the severity of AD symptoms and slow cognitive decline [129]. Additionally, a study by Stothart et al (2021) showed that EEG detected a significant difference in the recognition memory between AD patients and healthy older adults when they were tested using a fastball memory assessment [140].…”

Recent Advancements in the Early Diagnosis and Treatment of Alzheimer's Disease

“…EEG can detect electrical activity in the brain, record brainwave patterns, and reflect the underlying brain function. In 2021, Stothart et al [118] presented a new EEG method, Fastball, to measure recognition memory passively and objectively, which is fast and convenient and requires no comprehension of the task or behavioral response. It demonstrated that Fastball could distinguish AD from healthy individuals with high accuracy, providing a passive, objective, non-invasive, quick-toadminister method for the assessment of cognition in dementia.…”