Lying motionless	Lying without purposeful movement on the playing surface, for >2 s*. Does not appear to move or react purposefully, respond or reply appropriately to the game situation (including teammates, opponents, umpires or medical staff). Concern may be shown by other players or match officials (*> 2 s for removal and assessment of the athlete. Significantly longer periods of lying motionless may necessitate immediate and permanent removal from play, depending on the circumstances)
Motor incoordination	Appears unsteady on feet (including losing balance, staggering/stumbling, struggling to get up, falling) or in the upper limbs (including fumbling). May occur in rising from the playing surface or in the motion of walking/running/skating
Impact seizure	Involuntary clonic movements that comprise periods of asymmetric and irregular rhythmic jerking of axial or limb muscles
Tonic posturing	Involuntary sustained contraction of one or more limbs (typically upper limbs), so that the limb is held stiff despite the influence of gravity or the position of the player. The tonic posturing could involve other muscles such as the cervical, axial and lower limb muscles. Tonic posturing may be observed while the athlete is on the playing surface or in the motion of falling, where the player may also demonstrate no protective action* (*This was previously known as no protective action—stiff)
No protective action—floppy	Falls to the playing surface in an unprotected manner (ie, without stretching out hands or arms to lessen or minimise the fall) after direct or indirect contact to the head. The player demonstrates loss of motor tone (which may be observed in the limbs and/or neck*) before landing on the playing surface (*When the player’s arms are being held by a tackling opponent, this may only be observed in the neck, which was previously known as cervical hypotonia)
Blank/vacant look	The player exhibits no facial expression or apparent emotion in response to the environment* (*May include a lack of focus/attention of vision. Blank/vacant look is best appreciated in reference to the athlete’s normal or expected facial expression)