object = accScrollBar(wndID);
Will search for a child accessible object having the ROLE_SYSTEM_SCROLLBAR role.
A scroll bar has four child push buttons (accPushButton), corresponding to its arrows and page up/down regions, and one indicator (accIndicator) for its thumb. There is no default action for the scroll bar itself or for its indicator, however calling accDoDefaultAction on the child buttons will have the effect of a mouse click, thus generating a unit/page scroll. The value of a scroll bar (accValue) is its thumb position: an integer between 0 and 100.
wnd Overview | MS Accessibility