Because of the visual nature of some SWF files, the layout and navigation of the page can be complex and difficult for screen readers to translate. An overall description of the SWF file is important to communicate information about its structure and how to navigate through the site’s structure. You can provide this description by clicking the Stage and entering a description into the Accessibility panel. You can also create a separate area of the site to provide this description or overview.
Inform the user about any navigational elements that change in the SWF file. Perhaps an extra button is added, or the text on the face of a button changes, and this change is read aloud by the screen reader. Flash Player 7 and later supports updating these properties by using ActionScript. You can update the accessibility information in your applications if the content changes at runtime.