hello Lewy body dementa is the second most common cause of dementia after alzheimers disease this disease is famous for hallucination, dementia, loss in self interest, severe mouth and body muscle weakness, urinary incontinence and open mouth syndrome In open mouth syndrome , shows the more severe the dementia the more opening of mouth hence more urinary incontinence have you ever slept under a fan with mouth open? Same appears in open mouth syndrome due to lewy body dementia You cant close the mouth but following will help Mouth was like listerine regular posture changing placing a wet net cloth on mouthincrease the dose of donepezil or memantine mucolator satch use to decrease saliva thickness Keeping the mouth wet with a dropper , but i wont recommend high water intake as sodium is low in lewy body dementia , more water will cause more sodium dilution, moderate use of water is recommended hope this helps take care