samo
                    
                    
                    
                    
                    
                    
                    
                        
                        
                        does anyone know if a concussion usually   causes permanet brain damage.  I recently  fell about 3 feet and got knocked out.  I have no lingering problems etc.  I  recently read about diffuse axonal injuries  causing a simple concussion.  Are these  rare for a simple concussion from  low impact?