Parker lifted by January signings

West Ham have signed Wayne Bridge, Robbie Keane, Gary O'Neil and Demba Ba during the transfer window (GETTY IMAGES)

Scott Parker believes West Ham's signings last month will help give them the edge in the fight for Premier League survival.

"The additions we've made have improved us massively," Parker said ahead of Sunday's visit by Birmingham. "The signings have given everyone a lift. With the quality of players we've brought we can go from strength to strength."