symptoms of tbi are selected from the group consisting of amnesia confusion disorientation difficulty remembering new information headache dizziness blurry vision nausea vomiting ringing in the ears trouble speaking coherently and changes in emotions and sleep patterns in some embodiments the one or more symptoms of tbi are selected from the group consisting of amnesia confusion disorientation difficulty remembering new information headache dizziness blurry vision nausea vomiting ringing in the ears trouble speaking coherently and changes in emotions and sleep patterns the term u201c streptolysin o u201d as used with respect to the methods described herein means streptolysin o which has been modified by oxidation to eliminate cytotoxic effects while retaining important cholesterol binding characteristics on the cell membrane streptolysin o is readily oxidized in solution and is commercially available sigma product catalog the dose of streptolysin o administered to the subject can be determined by the physician taking into account age sex weight etc of the subject in some embodiments the streptolysin o is administered in a dosage amount ranging from about 0 00016 ng to about 3200 ng per dose in some embodiments the streptolysin o is provide at a dose of about 0 016 ng or about 0 02 ng or about 0 05 ng or about 0 1 ng or about 0 2 ng or about 0 3 ng or about 0 4 ng or about 0 5 ng or about 1.