Massa's current situation got me to thinking about drivers who have returned from serious injury and how their form was affected (if at all). The last driver I can recall being in a coma after a shunt was wendlinger in'94. IIRC he did return but was never the same driver again.
Lauda is another obvious example and aside from those early races after his return seemed to be largely the same behind the wheel.
Any other examples?
