The Glasgow Coma Scale (GCS) was created in 1974 by academics Bryan Jennet and Graham Teasdale to evaluate coma and impaired consciousness in an emergency setting. The scale employs three clinical findings: eye response, motor (muscle) response and verbal response. Scores ranged from 3 (deep coma) to 15 (fully aware). The desire was to create a uniform measurement that emergency physicians could use all over the world to describe a patient’s initial level of consciousness. A number that was quick, easy to assess, and was thought to have value in the short-term and long-term prognosis of traumatic brain injury (TBI) patients. It was called the Glasgow Coma Scale (GCS).
The scale was widely adapted and undoubtedly has proven clinical value, but like any simple number, it frequently fails to account for long-term prognosis. Some patients who are initial low scorers recover completely and some “15”s suffer chronic problems.
Thus, The University of Glasgow‘s Sir Graham Teasdale has joined with Paul Brennan and Gordon Murray of the University of Edinburgh to create a new updated scale.
Why is this important? Because the current method, even though widely used in emergency departments, has proven to have little long-term predictive value. Thus, experts referring to initial Glasgow Coma scale numbers have become too comfortable in relying upon the number. Physicians and researchers love numbers but those numbers need to represent something meaningful if continued use can be justified.
The new scale uses an individual’s initial GCS score with information on pupil reactivity to light (see last week’s blog), the patients age, and head CT findings. Age appears to be an important prognostic factor. To no great surprise, older patients do worse after head trauma. initial CT scan abnormalities were found to be useful when they were available.
The effort was to develop curves representing level of function six months after injury. This information may have a tremendous impact on how aggressively to intervene and to capture which patient population needs close follow-up. The ultimate goal would be to find an early intervention (drug or other modality) that could prevent poor outcomes.
The effort to improve initial evaluation of TBI patients is a central theme in my blog. Currently, the medical system misses large numbers of patients who are lost after initial emergency evaluation. More patients never even get examined, but that’s a larger societal problem and no improved GCS will help people who are never seen.
The importance of pupillary response is once again emphasized as having a central role in TBI evaluation. CT scans if they show large bleeds are clearly not good prognostic indicators, but most patients entering an Emergency Room have normal Head CT scans and this can be falsely reassuring.
The GCS will continue to play an important role in the TBI patient. I mostly see patients with mild TBI (mTBI) and the GCS has even less value in these patients’ long-term function. There needs to be simple but more extensive cognitive measurements that can be routinely administered to potential patients after head trauma. For example, women and their children fleeing domestic violence should undergo routine TBI evaluation at all shelters currently maintained.
The history of the GCS reads like the history of TBI- we are just beginning to find out what’s really happening in the brain.
Steven H. Rauchman, M.D. is an eye physician and surgeon who has been in private practice for 30 years. He has served as a Traumatic Brain Injury (TBI) medical/legal expert for the last 6 years specializing in the area of personal injury and related traumatic brain injuries.