A forgotten epidemic left survivors frozen for decades

Between roughly 1917 and the mid-1920s, a strange sleeping sickness called encephalitis lethargica swept the world, killing many and leaving others with lasting damage to brain regions that regulate movement and initiative. Some survivors slipped, sometimes gradually, into a state resembling advanced Parkinsonism: rigid, nearly motionless, often unable to initiate speech or action, yet frequently still aware inside.

Sacks encountered dozens of these patients decades later, warehoused in a Bronx hospital, largely forgotten by mainstream medicine because their condition didn't fit tidy diagnostic categories and because the epidemic itself had faded from public memory. Many had been institutionalized so long that staff assumed there was little inner life left to reach.

Sacks's first move was simply insisting these patients were still present — minds trapped inside stilled bodies rather than absent minds in empty shells. That reframing, treating profound stillness as imprisonment rather than emptiness, set up everything that followed when a new drug offered the possibility of release. Absence of movement is not absence of person.