Calc Function

    • Calcs that help predict probability of a diseaseDiagnosis
    • Subcategory of 'Diagnosis' designed to be very sensitiveRule Out
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    • Numerical inputs and outputsFormula
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    Chief Complaint


    Organ System


    Patent Pending

    Simplified Motor Score (SMS)

    Simplifies assessment of head trauma patients compared to the GCS.


    Score the patient's best response.

    When to Use
    Why Use

    For evaluation of patients in the pre-hospital and acute care setting for possible traumatic brain injury.

    The Simplified Motor Score (SMS) has been suggested as a replacement for the GCS in the evaluation of patients for traumatic brain injury.

    • A meta-analysis of 5 studies (102,132 total subjects) found that for predicting clinically significant TBI, need for neurosurgery, and need for intubation, the SMS and GCS were statistically equivalent.
    • A prospective study involving 126 trauma patients found that the SMS had significantly greater inter-rater reliability (83%) than the GCS (32%) when performed within 5 minutes of each by two ED physicians who were blinded to the other’s assessments.

    Points to keep in mind:

    • It should be noted that all comparisons of the discriminatory value of the SMS compared to the GCS were retrospective reviews of prospectively collected registry data.
    • There is no published data on whether observed differences in performance between the SMS and GCS are truly clinically insignificant as is asserted by the authors of several of the comparative studies.

    The Simplified Motor Score allows providers to rapidly assess trauma patients using a score that is significantly simpler than the GCS, has higher inter-rater reliability and comparable sensitivity for significant traumatic brain injury, the need for neurosurgery and/or intubation and death.

    Though the composite GCS has been almost universally adopted, there are concerns about its poor reproducibility and the validity of using the composite score. The SMS offers a convenient and viable alternative.

    Obeys commands
    Localizes pain
    Withdrawals to pain or worse


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    Next Steps
    Creator Insights
    Dr. Steven Green

    From the Creator

    Why did you develop the Simplified Motor Scale? Was there a clinical experience that inspired you to create this tool for clinicians?
    The literature evidence is now overwhelming that the Glasgow Coma Scale is unreliable, inaccurate, and unnecessarily complex in that simpler scales are just as predictive. The SMS is the worthwhile part of the GCS statistically distilled out to remove the bloat, and with far better inter-rater reliability.
    What pearls, pitfalls and/or tips do you have for users of the Simplified Motor Scale? Are there cases in which it has been applied, interpreted, or used inappropriately?
    The simplicity of the score avoids the pitfalls of more complex scales.
    What recommendations do you have for health care providers once they have applied the Simplified Motor Scale? Are there any adjustments or updates you would make to the score given recent changes in medicine or imaging?
    No additional recommendations or updates.
    Other comments? Any new research or papers on this topic in the pipeline?
    A study in Annals of Emergency Medicine found that prehospital providers can only calculate the GCS correctly 40% of the time, underscoring its inability to be remembered and applied. (Feldman A, et. al. Randomized Controlled Trial of a Scoring Aid to Improve GCS Scoring by EMS Providers. Ann Emerg Med 2015) A potent argument for a simpler scale.

    About the Creator

    Steven Green, MD, is a professor of emergency medicine and pediatrics at Loma Linda University, California. He currently is an attending physician in the emergency room and also conducts research on subjects like sedation and emergency protocols.

    To view Dr. Steven Green's publications, visit PubMed

    Content Contributors
    About the Creator
    Dr. Steven Green
    Content Contributors