A method administers quaternary ammonium anti-cholinergic muscarinic receptor antagonists in combination with acetyl-cholinesterase inhibitors to treat either cognitive impairment or acute delirium. This therapy results in a modification of a cognitive disorder or disease, namely a slow down in the disease progression. In one preferred embodiment, the disease is dementia with Lewy Bodies. New formulations for quaternary ammonium anti-cholinergic muscarinic receptor antagonists are also disclosed.