In the hospital, older patients frequently go through a process called sundowning or delirium, where they see and imagine things that don’t exist. The etiology of this has to do with an aberrant sleep-wake cycle. Nurses and doctors constantly check in on patients throughout the night and wake them up to get blood tests, check blood pressures, and monitor health status. This disrupts sleep quality, eventually leading to an acute but reversible state of altered mentation. These patients sometimes see dead loved ones reincarnated, believe they are in a foreign country, or see doors and windows where there are none. After a good night’s sleep, however, they regain awareness of what is and what is not real. This process is different from dementia, a chronic and deleterious pathology unhindered by peaceful repose. The classic example of dementia is Alzheimer’s Disease, which leads to progressive memory loss, incapacitation, and eventually death.

On a night shift during my surgery rotation, I was instructed by a resident to start an intravenous line on a patient with advanced Alzheimer’s to deliver medications. He was an older gentleman with graying hair, wrinkled and tan skin, and yellowed nails. His hands and feet were swollen and edematous from fluids that had leaked out of the blood vessels into various compartments of the extremities. He had restraints on — his hands and feet were tied down to the bed — because he occasionally got violent. His forehead glistening from sweat, a full head of white hair, and in a hospital gown, he was outwardly similar to other elderly hospital patients. But while other elderly and delirious patients eventually understand why they are in the hospital and who their family members are, this patient did not have such a prognosis. His dementia irreversibly ate away at the fundamental qualities that once made him a unique and identifiable individual to his friends and family.

He looked up at me as I approached the bed clutching the needle, alcohol swab, and gauze pads necessary for starting the IV and asked me a question that I could not understand. The nurse standing at the bedside told me that he thought I was his wife and that he frequently confused people he met with his spouse. I shook the patient’s hand and introduced myself but he responded merely by reaching out to me, sitting up in the bed and staring at me, eyes glazed over seemingly in another world. I hesitated: Was he cognizant in any way of his surroundings, of who he was, of what his life was like? Before Alzheimer’s set in, what kind of active life did he lead? I did my duty, started the IV, and left, allowing the patient to get back to sleep.

Later that evening, I met a patient even further away from our world. He was in his sixties and had drunk so much liquor that his brain had completely atrophied, or shrunk. Tall and burly, he maintained his physical build but could not recognize anyone, converse, or understand what was said. He got up and walked around, faced the corner of the room, stared at the wall, lightly touched it, mumbled gibberish and about-faced. He neither saw nor heard me. His aimless sauntering demonstrated some retained primal instinct, purposeless beyond a need to keep the muscles of his legs from withering away. His wife, whom he didn’t recognize, cared for him as she would a baby: bathing him, clothing him, feeding him, and fearing the moments when he became aggressive and violent with her. Who was he before he began to drink? Who was he before dementia set in and removed the man his wife once knew?

These encounters during the graveyard shift, disturbing and brief though they were, raise some larger questions about patients who are so demented that they lose a sense of self and the world that surrounds them. What makes them human? They solely retain the need to eat and sleep, the kind of primitive qualities, necessary only to live, characteristic to all beings. Are they in some purgatorial state between human and beast, between life and death, merely waiting for the day when they will shuffle off this mortal coil?

The debate about what makes us human is voluminous, and relevant to the medical profession, which frequently confronts patients with end-stage dementia. John Locke’s Essay Concerning Human Understanding, published in 1690, touches on this issue. Locke writes that a person is “a thinking intelligent being, that has reason and reflection, and can consider itself as itself, the same thinking thing, in different times and places; which it does only by that consciousness which is inseparable from thinking, and, as it seems to me, essential to it: it being impossible for any one to perceive without perceiving that he does perceive…. Consciousness makes personal identity.” Thus, those so demented that they lose awareness of themselves or the ability to think are no longer persons. But this definition seems incomplete. After all, are not infants living, breathing human beings? And yet, they initially lack the kind of reason and reflection to which Locke refers. In EmbryoRobert P. George and Christopher Tollefsen address Locke’s argument and the question of what makes us human.

Professors George and Tollefsen point to an even more absurd example than a newborn: “human beings who are in a dreamless sleep, or in a deep coma, seem not to possess the relevant properties [that make them human].” The same might be said of the transiently delirious hospital patients, who lose the ability to perceive the world accurately. And, indeed, these people, like the patients I encountered that evening, lack “immediately exercisable capacities for mental functions characteristically carried out by most human beings,” as George and Tollefsen write of immature human life. But “we must,” they continue, “distinguish two senses of the capacity (or, as it is sometimes called, the potentiality) for mental functions, psychological states, and so on: an immediately exercisable one, and a basic natural capacity, which develops over time.” Because infants and humans in a deep sleep or delirium have a capacity for mental function that eventually develops when they grow up or awake, they too are human beings.

Perhaps a similar line of argument ought to be applied to those with end-stage dementia. They don’t have the potential to become fully conscious and reasoning beings — but they once had that capacity. They once had memories, perceptions, and feelings. They once socialized with friends. They once worked. They once raised children. And because of that, we owe them the kind of care and decency that we provide to those newborns not yet conscious of reason and thought.

I realize that this is merely a brief post about a topic that is worth its weight in thousands of pages, and thus I’m acutely aware of how insufficient this is. But it is an issue that continues to come up during third year and an issue which I will try to write about further as the year goes on.