Severe dementia usually occurs in the third stage, the dementia stage, which is also the severe dementia stage. The patient presents with severe dementia, no longer knowing who they are and not recognizing their loved ones. There is complete silence, or only a few spontaneous words, until no speech is possible. The patient’s activity decreases and gradually loses the ability to walk, and eventually cannot stand and walk until he or she is completely bedridden, incontinent, and completely loses the ability to take care of himself or herself. Patients in this stage are often accompanied by severe malnutrition, bed sores, myasthenia gravis, and diseases of the cardiac and pulmonary systems.