Humanized antibody that does not bind to Aβ monomer, specifically binds to only Aβ oligomers, containing as an active ingredient the antibody, anti-cognitive dysfunction agents, Alzheimers disease therapeutic agents, Aβ amyloid fibril formation or senile plaque formation inhibitor comprising the step of administering an inhibitor, an antibody, a method for one, and including the step of administering the antibody, a method of inhibiting the progression of Alzheimers disease, at least in the prevention and treatment of Alzheimers disease or cognitive impairment.Aβモノマーに結合せず、Aβオリゴマーのみに特異的に結合するヒト化抗体、該抗体を有効成分として含有する、抗認知機能障害剤、アルツハイマー病治療剤、老人斑形成抑制剤またはAβアミロイド線維形成阻害剤、該抗体を投与する工程を含む、認知機能障害またはアルツハイマー病の予防および治療の少なくとも一方のための方法、並びに該抗体を投与する工程を含む、アルツハイマー病の進行を抑制する方法。
