Overview
This lecture reviews the ASIA (American Spinal Injury Association) motor and sensory exam, the ASIA Impairment Scale, and prognostic outcomes for spinal cord injury patients.
ASIA Motor and Sensory Exam
- The ASIA exam assesses motor and sensory function in all spinal cord injury patients.
- Exam includes testing dermatomes (skin sensation areas) and muscle groups with expected total scores.
ASIA Impairment Scale (AIS) Grading
- AIS grades range from A (complete) to E (normal), determining the extent of impairment.
- A (Complete): No sensation or motor preserved below injury, including sacral segments (S4-S5).
- E (Normal): Full motor and sensory function everywhere.
- B (Incomplete): Sensory but no motor function below neurologic level; sacral sensation present.
- C (Incomplete): Motor preserved below level, but over half of key muscles have strength grade <3.
- D (Incomplete): Motor preserved below level, over half of muscles grade ≥3; can include mild weakness only.
Prognosis and Outcomes
- Patients graded A (complete injury) have ≤10% chance of regaining any ability to walk, often with braces.
- Patients graded B (incomplete) have about 33% chance to ambulate, mainly due to preserved sacral sensation.
- Patients graded C (incomplete) see about 75% achieve some ambulation with recovery.
- Grade D patients generally recover well, with relatively minor impairment.
Key Sensory Landmarks
- T4 dermatome aligns with nipple level.
- T10 dermatome aligns with umbilicus (belly button) level.
Key Terms & Definitions
- Dermatome — Area of skin supplied by a single spinal nerve.
- Muscle Grade — Scale measuring muscle strength, with 5 as normal and <3 indicating significant weakness.
- Sacral Segments (S4-S5) — Lowest spinal cord segments critical for bowel/bladder and perirectal sensory testing.
- Ambulate — To walk or move about.
Action Items / Next Steps
- Review the ASIA Impairment Scale criteria for each grade (A-E).
- Memorize dermatome key sensory landmarks, especially T4 and T10.
- Practice performing and scoring the ASIA motor and sensory exam.