Freud was also an early researcher in the field of cerebral palsy, which was then known as "cerebral paralysis". He published several medical papers on the topic, and showed that the disease existed long before other researchers of the period began to notice and study it. He also suggested that William John Little, the man who first identified cerebral palsy, was wrong about lack of oxygen during birth being a cause. Instead, he suggested that complications in birth were only a symptom.