The Dons have one win from their three games, but their two away games have seen two defeats and 11 goals conceded.
A statement made on the club's website read: "Following the heavy defeats in the last two away games, the AFC Wimbledon board held detailed discussions with the club's manager, Terry Brown, earlier in the week.
"The discussions were frank and constructive and focused on the actions that are needed to ensure that results improve before the season gets too much older.
"A number of actions were agreed, and Terry confirmed that that our defensive coach, Stuart Cash, will be working with the defence at all training sessions so as to ensure we improve over recent performances.
"All the agreed actions will be implemented immediately."