The Benandanti ("Good Walkers") were members of an agrarian visionary tradition in the Friuli district of Northern Italy in the 16th and 17th centuries. The Benandanti claimed to travel out of their bodies while asleep to struggle against malevolent witches. According to Early Modern records, benandanta were believed to have been born with a caul on their head, which gave them the ability to take part in nocturnal visionary traditions.
The thing about the caul (Abra was born with one) and the fact that she is italian (from her mother's side) made me think that there could be a conection.
Just a thought.