Adding filter in Comments at admin panel

Hi all,

I’m trying to add a filter like this in comments area in admin panel,

http://wordpress.stackexchange.com/questions/45436/add-filter-menu-to-admin-list-of-posts-of-custom-type-to-filter-posts-by-custo

However, I can’t figure out how to modify the parse_query part and how it works. The filter the comments by the author. That is only display the author’s comment has been chosen in the dropdown list.

Is there any tutorial might help?