Frail phenotype is associated with distinct quantitative electroencephalographic findings among end-stage renal disease patients: an observational study oleh Chia-Ter Chao, Hsin-Jung Lai, Hung-Bin Tsai, Shao-Yo Yang, Jenq-Wen Huang, on behalf of COhort of GEriatric Nephrology in NTUH (COGENT) study group