All perfect praise be to Allaah, the Lord of the worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger. If you mean that the patient supplicates Allaah The Almighty by His Name that is relevant to his disease— for example, saying, "O Ever-Beholding, restore my sight."— then this is permissible, provided that it is not fixed to a certain number or a period of time. Please read Fatwa 97265. If you mean that the patient repeats a Name of Allaah The Almighty solely— for example, saying, "Allaah…Allaah…Allaah," or " the Ever-Hearing… the Ever-Hearing… the Ever-Hearing."— then this is impermissible, as it is an innovation (Bid’ah). And Allaah Knows best.