The study looked at patients with auto-activation deficit, a syndrome characterized by extreme apathy. People with auto-activation deficit lose the ability to spontaneously activate any cognitive or emotional processes. They report that they don't have any thoughts at all, called "mental emptiness." They often sit quietly in the same place all day without speaking or moving. If someone prompts them, they can answer questions and recall memories, but left to their own devices, their minds remain blank. So if these patients don't have spontaneous thoughts, do they dream?