Correlation between frailty and reduction in cortical thickness in patients with chronic obstructive pulmonary disease oleh Ayumi Fukatsu-Chikumoto, Tsunahiko Hirano, Shun Takahashi, Takuya Ishida, Kasumi Yasuda, Tomohiro Donishi, Kazuyoshi Suga, Keiko Doi, Keiji Oishi, Shuichiro Ohata, Yoriyuki Murata, Yoshikazu Yamaji, Maki Asami-Noyama, Nobutaka Edakuni, Tomoyuki Kakugawa, Kazuto Matsunaga