How to get sound from computer to tv using a MiniDisplayPort to VGA adapter?

Using a Mini DisplayPort to VGA adapter I am able to get my computer screen onto my TV display. However, there is no sound. My MacBook Pro does not have a Mini DisplayPort and a Mini DVI port -- only a Thunderbolt. Is there any way to get my computer sound to go through to my TV output speakers?

Thanks for any assitance.