Kauṣītaki Upaniṣad 3.3.37

3.3.37

manaḥ sarvair dhyānaiḥ sahāpyeti /

When a sick person about to die comes to such weakness that he comes to a stupor (_sammoha_), then they say of him: ‘His thought (_citta_) has departed. He hears not. He sees not. He speaks not with speech. He thinks not.’ Then he becomes unitary in this breathing spirit (_prāṇa_). Then speech together with all names goes to it; the eye together with all forms goes to it; the ear together with all sounds goes to it; the mind together with all thoughts goes to it.