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
    • Med treatment and moreTreatment
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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


    The Simplifed Motor Score (SMS) is defined as:

    • Obeys commands = 2
    • Localizes to pain = 1
    • Withdrawals to pain or worse = 0.

    Patients with a SMS of <2 are at significantly increased risk of having a significant traumatic brain injury and prompt evaluation and head CT imaging is indicated for these patients.


    Clinical management decisions should not be based solely on the SMS score, though scores of < 2 are associated with worse clinical outcomes. The threshold for obtaining a head CT in these patients should be low.

    Critical Actions

    As with the GCS, management decisions should be based on the patients overall clinical picture. However the SMS appears to have similar sensitivity to the GCS for predicting patients at risk of significant TBI.

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    About the Creator
    Dr. Steven Green
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