The Glasgow Coma Score: misunderstood and overused?

The Glasgow Coma Scale (GCS), developed by Teasdale and Jennett in 1974, is widely used to assess consciousness after an injury. It scores eye opening, motor responses, and verbal responses, with the total score often used as a summary of injury severity.

But in medicolegal cases, the GCS is frequently misunderstood. Here’s why:
🔹 Misconception: "A GCS of 15 means no brain injury."
The GCS primarily assesses alertness, not cognition.  It includes only one item that indirectly considers confusion, and that judgment is subjective. A person may appear lucid but still have subtle cognitive deficits.
🔹 Misconception: "A low GCS always predicts long-term impairment."
GCS scores can be influenced by language barriers, pre-existing conditions, hearing or speech impairments, or intoxication. A transiently low score doesn’t necessarily mean a poor outcome—just as a high score doesn’t rule out persistent issues.

Why It’s Not Enough

The GCS doesn’t assess:
✅ Cognitive dysfunction—both subtle and more pronounced (e.g., executive function, memory, processing speed)
✅ Post-injury recovery trajectory—how impairments evolve over time
✅ Long-term functional impact—the ability to return to work or daily life
What Should Be Considered Instead?

For a comprehensive assessment, other factors must be evaluated:
✔️ Loss of consciousness, post-traumatic amnesia duration, and neuroradiological findings—These provide better indicators of injury severity.
✔️ Neuropsychological evaluation—Identifies cognitive and functional impairments.
✔️ Longitudinal follow-up—Symptoms often become more apparent over time, particularly when individuals return to work or face cognitive demands.
Takeaway
The GCS is a useful tool, but it’s not the final word on brain injury. Mild TBI (mTBI) remains a heterogeneous category, and recovery is highly individual. In legal cases, a full neuropsychological assessment provides a much clearer picture of cognitive function and long-term impact.