Neuropsychiatric symptoms of Alzheimer’s dementia and their association with dorsolateral prefrontal cortex TMS evoked potentials

Background Alzheimer’s Dementia (AD) is characterized by cognitive and neuropsychiatric symptoms (NPS). Recently, decline in AD has been linked to increased cortical excitability. However, the relationship between NPS excitability remains unclear. This study investigated dorsolateral prefrontal cortex (DLPFC). Method 24 participants with probable diagnosed using National Institute of Aging-Alzheimer’s Association criteria (Mage (SD) = 74.1 (7.2) years) were recruited followed for up 6 months. Global cognition was assessed Montreal Cognitive Assessment (MoCA). Neuropsychiatric Inventory Questionnaire (NPI-Q) total score subdomain scores. Single pulse transcranial magnetic stimulation (TMS) applied at DLPFC (localized MRI-based neuronavigation) a frequency 0.1 Hz, sufficient intensity; collected 62 channel electroencephalography (EEG) recorded from scalp. TMS-evoked potential (TEP) peak amplitudes individual TEP peaks (P30, N45 P60) calculated. Result NPI-Q severity positively correlated P30 (r (19) .64, p .003) negatively (22) -.46, .033). These associations remained significant after controlling age, sex (DLPFC (ß .93, .001) -.47, .031)). Further, month follow baseline (16) -.56, .025). Among subdomains, apathy -.42, .049). Conclusion burden associated excitatory activity (i.e., P30) inhibitory N45) combined TMS-EEG over DLPFC. largely driven domain. findings may have implications developing neurophysiological biomarkers targeted treatment interventions AD.