What is this Project?

Working under Dr. Alexander Choi at Banner Health in the Neurodegenerative disease department, I pursued a project to analyze cognitive decline using EEG. Alzheimer’s disease and Parkinson’s disease are both increasingly common neurodegenerative disorders that cause cognitive decline found in older adults. 40-60% of individuals above the age of 60 have mild cognitive impairment (MCI) defined by Parkinson’s disease (PD) and Alzheimer’s disease (AD)1,2. Differentiating between these patients based on their cognitive profiles will facilitate the assessment of disease worsening and improvement, including the prediction of dementia conversion. Approaches to preventing and treating cognitive decline have largely been unsuccessful3. EEG has shown value in research of neurodegenerative disease as a biomarker of disease state7 and is recognized as an ancillary study for the clinical definition of Lewy Body Dementia with accuracy compared to AD8. By understanding EEG markers that correlate with cognitive decline in AD or PD, criteria to distinguish between MCI pathologies could be established. EEG has been increasingly used for diagnosing dementia pathologies4 because it is comparatively inexpensive, non-invasive, and allows for continuous monitoring. Specifically, the Grand Total EEG (GTE) score and similar visual rating scales for EEG have been used successfully in previous studies to differentiate between dementia with Lewy bodies and AD5,6. Using qualitative EEG analysis to distinguish between MCI pathologies is not frequent in clinical settings, which might be due to the absence of a reliable scoring method.

A Little about the Method:

As part of the Brain and Body Donation Program, EEG data was collected from individuals in addition to neuropsychology testing and post-mortem diagnosis. 484 donors were analyzed, comprising 1187 EEG exams. Of these, 77 donors had final consensus cognitive diagnosis of MCI prior to death, which comprised the focus of this analysis. Only participants with MCI due to AD, PD, Tauopathy, or Argyrophilic granules (AG) were used, in addition to participants who were diagnosed with both AD and PD. Participants who had both tauopathy and AG were considered under tauopathy since the AG group was being used as a control. Frontal and Parietal spectral power, as well as a visual rating scale metric, were analyzed to explore their impact on cognitive worsening. The visual rating scale used was modeled after the Van der Zande study6, with 1 = normal, 2 = mildly abnormal, and 3 = diffusely abnormal. Cognitive worsening was defined by diagnostic worsening and a MMSE score.