Post-injury motor behavior is assessed via the Basso, Beattie and Bresnahan (BBB) locomotor scale method. The BBB score is used for function recovery and locomotors testing in chronic SCI study. The scale (0 – 21) represents sequential recovery stages and categorizes combinations of rat joint movement, hindlimb movements, stepping, forelimb and hindlimb coordination, trunk position and stability, paw placement and tail position.
Each rat is then assigned to one of three categories, depending on their score:
- Early Stage (score of 0 – 7): Composed of isolated joint movements with little or no hindlimb movement
- Intermediate Stage (score of 8 – 13): Intervals of uncoordinated stepping
- Late Stage (score of 14 – 21): Forelimb and hindlimb coordination
Due to a naturally recovering reflex in rats, even spinal cord injured rats regain their ability to walk within the weeks following injury. The hindlimbs are able to generate a spinal reflex arc that allows hindlimb stepping without the use of the brain. For this reason, data collected from SCI rats generally improves for the first few weeks, then plateaus at some value, which is indicative of the extent of permenant damage