They can often look very similar initially but with experience and some slightly different symptoms you can end up telling them apart.
PT - usually in older rats, has a bunch of very classic symptoms like having difficulty grasping or not able to grasp with front paws. Involuntary head bumping when you stroke over their head or head lifting on their own. Clubbed paws, a weakness or looseness through the body, dull eyes, confusion, falling over and then popping back up, having stiff forelimbs and pushing back on them (I call this PT pushback), excessive bruxxing, not eating very adeptly (soft foods etc). You might even think they are blind. They don't usually circle like inner ear but they can a little with the weakness. Losing "edge behaviour" where a rat stops and looks down off an edge, these guys often tumble or slide off.
Inner ear - head tilt, circling, discharge from ear, these are the most common symptoms. Falling from shelves etc from dizziness. Often times a rat will fall and people consider that the injury when its really the dizziness of inner ear infection that causes the fall.
Stroke - this is the hardest one to determine IMO. Usually one side of the body will be weaker, even the mouth on one side will droop.