Graded Hermitian forms and Springer's theorem

An analogue of Springer's theorem on the Witt group of quadratic forms over a complete discretely valued field is proved for Hermitian forms over division algebras over a Henselian field, including some cases where the residue characteristic is 2. Residue forms are defined by means of vector space valuations as Hermitian forms on the graded modules associated with the induced filtrations.