When people who have this difficulty are listening to another speak to them, they are often busy planning how to respond. They might be planning a defense of their position if a disagreement is involved; or, they might be 'shutting down' if they are listening to something they don't want to hear. Others may be busy trying to make a favorable impression and therefore are busy monitoring the dialogue, rather than hearing it, in order to insure that they are viewed positively.
An updated version of Listening Patience - Part 1 is included in my new book, Help Me!. More information, including the table of contents, reviews and purchasing information is available on the Help Me! page.