Well, that's a load of ****. I can remember DS having at least 1 assist (Stoke away) and I believe DP has 3.
Edit:
Just looked it up on PL website:
8. Pascal Groß
3. José Izquierdo, Davy Pröpper & Dale Stephens
2. Tomer Hemed
1. Shane Duffy, Lewis Dunk, Anthony Knockaert, Jürgen Locadia...