( Concussion ( ( ( is not ) ( ( the ( only form ) ) ( of ( traumatic ( brain injury ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Concussion)) (VP (VBZ is) (RB not) (NP (NP (DT the) (JJ only) (NN form)) (PP (IN of) (NP (JJ traumatic) (NN brain) (NN injury))))) (. .)))
Concussion is not the only form of traumatic brain injury.
(ROOT (S (NP (DT A) (PRN (-LRB- -LRB-) (NP (NN n)) (-RRB- -RRB-)) (NN concussion)) (VP (VBZ is) (NP (NP (DT the) (ADJP (RBS most) (JJ common)) (NN type)) (PP (IN of) (NP (NN brain) (NN injury))))) (. .)))