Cadsuane's hairpiece is a ter'angreal. It likely prolongs her life and protects her under certain scenarios, providing warning, etc. She is never without it, and it felt cold against her head when another sister held the power in her presence (POD). It may also do interesting things for her when men channel in her presence. She reminisces about how whe has never lost a decoration from her hairpiece since she started wearing it, due to carefully accounting for it all the time. Food for thought.