The BDI Test Explained

We perform a cognitive screening test based on quantitative electroencephalography (EEG), which is used to detect brain-wave slowing (i.e., the shift of spectral power from higher to lower EEG frequencies [1,2,3]). Brain-wave slowing may be associated with cortical neurodegenerative changes [4,5,6] and can thus be used as a screening tool for early dementia detection [7,8,9].

We measure brain-wave slowing with the BrainTrip Dementia Index (BDI)* test [10]. During the BDI test, 4 minutes of resting state EEG with eyes open and 4 minutes with eyes closed is recorded. The EEG data is then algorithmically pre-processed and used to measure brain-wave slowing. The result of the BDI test is an estimate of brain-wave slowing, which is presented on a scale between 0 and 100 points.

BDI values between 60 and 100 points indicate that EEG frequencies are within the normal or reference range. BDI values between 40-60 points are intermediate and indicate only a mild slowing of EEG waves. BDI values between 0-40 points indicate a noticeable slowing of EEG waves, which suggests the probable presence of cortical changes potentially related to cognitive decline or dementia. At the cut-off score of 50 points, the BDI test has 94% specificity and 77% sensitivity for detecting cognitive decline or dementia.

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* BDI testing is a cognitive screening tool and cannot, by itself, confirm or exclude the presence of dementia. BDI test results must always be interpreted in the context of the subject’s overall health status in consultation with a medical doctor, clinical psychologist, or another specialist trained to evaluate human cognitive processes.