Krishach is correct. I think it's very important to realize that Ghoul PC's are getting the critter power
"Enhanced Senses" and not the adept power
"Improves Senses". These things, while similarly titled, are not related. Looking up the rules for
Improved Senses will not help you to understand what
Enhanced Senses does for you.
The problem, previously, was that the critter power
"Enhanced Senses" was not sufficiently defined in the Friends and Foes chapter of SR4 or SR4a. Even when running ghouls as a GM, it wasn't clear what this power did for ghouls. When they made ghouls a playable character type in the Runners Companion, they gave them the critter power
"Enhanced Senses", not the adept power
"Improves Senses", and thus players also didn't know what these powers did for their characters.
Running wild has clarified this specifically. If you are playing a ghoul, you get +2 dice when making a perception test that uses smell or hearing. Additionally, if you read on, it says on page 205:
QUOTE
An enhanced sense may also provide the critter with new uses for skills. Enhanced Scent, for example, allows a trained critter to track a person or prey by scent alone. Scent tracking uses Tracking + Intuition. Thresholds and dice pool modifiers are provided.
But, once again, this has nothing at all to do with the adept power
"Improves Senses". So, there's really no point in discussing it here any further.