Fastball is a new electroencephalogram (EEG) method developed by researchers from University of Bath, UK, for the passive and objective measurement of recognition memory that could allow for earlier diagnosis of Alzheimer disease (AD), according to study results published in the journal Brain.
As the diagnosis of dementia occurs relatively late in the disease process, there is a great need for early diagnostic tools. Fastball EEG is intended to provide an alternative measure of recognition based on the neural response to previously encountered images. Participants passively view rapidly presented images and EEG is used to assess their automatic ability to differentiate between images based on previous exposure.
The objective of the current study was to measure recognition memory in patients with Alzheimer disease using Fastball, under the assumption that patients with the neurodegenerative disease would show reduced recognition memory performance.
The study sample included 20 younger control individuals (mean age, 24 years; 8 men), 20 healthy older individuals controls (mean age, 74 years; 11 men), and 20 patients with AD (mean age, 79 years; 11 men). All participants completed the Fastball task and were not instructed to attend to previously seen images and provided no behavioral response.
A 2 alternative forced choice (2AFC) task was completed immediately following each of the 3 Fastball tasks, during which 16 previously seen images were paired with 16 previously unseen images. The participants were then asked to indicate which image they had seen during the experiment.
Significantly impaired recognition memory was detected according to Fastball EEG in participants with AD, compared with healthy older adults (P <.001), while no difference was noted for behavioral recognition between patients with AD and healthy older adults.
Fastball measure of recognition memory was highly accurate for discriminating healthy older adult controls from patients with AD (area under the curve, 0.86; P <.001), but behavioral 2AFC was not accurate (area under the curve, 0.63; P =.148).
Healthy ageing had no significant impact on the results, as outcomes of the Fastball task and behavioral 2AFC task were similar among older and younger adult control individuals.
The study had several limitations, including greater difficulty in the fixation cross color change task among patients with AD, which raises the possibility that lower attentional engagement with the task had an impact on the results, although the researchers do not believe this was the case.
“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,” concluded the researchers.
Stothart G, Smith LJ, Milton A, Coulthard E. A passive and objective measure of recognition memory in Alzheimer’s disease using Fastball memory assessment. Brain. Published online Septemeber 20, 2021. doi: 10.1093/brain/awab154