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Brain Injury Criteria (BrIC)

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Overview

Developed for the purpose of capturing rotational head motion in one metric, the Brain Injury Criteria (BrIC) was introduced in its current form in 2013[1]. BrIC is essentially a resultant of a weighted peak rotational velocity of the head.

    \[BrIC = \sqrt {\left({\frac{{{\omega _x}}}{{{\omega _{xc}}}}\right)^2 + \left({\frac{{{\omega _y}}}{{{\omega _{yc}}}}\right)^2 + \left({\frac{{{\omega _z}}}{{{\omega _{zc}}}}}\right)^2 \]

 

Panel Descriptions
3D Representation of Sensor Location and Local Coordinate System Used for ProcessingSummary Table with Risk of AIS 1-6 Injury and BrIC value
Time-History Plot of Rotational Head VelocityInjury Risk Curves for BrIC

Calculation Methods

1. Obtain resultant head rotational velocity from head CG

2. Calculate BrIC according to

    \[BrIC = \sqrt {\left({\frac{{{\omega _x}}}{{{\omega _{xc}}}}\right)^2 + \left({\frac{{{\omega _y}}}{{{\omega _{yc}}}}\right)^2 + \left({\frac{{{\omega _z}}}{{{\omega _{zc}}}}}\right)^2 \]

where \omega_x, \omega_y, and \omega_z are the peak values of absolute rotational velocity in the x, y and z directions respectively.  \omega_x_c, \omega_y_c, and \omega_z_c are the critical values for each direction.

3. Critical values for rotational velocities are provided in the following table:

Critical Values

 CSDM Based

(rad/s)

 MPS Based

(rad/s)

 Avg of CSDM and MPS

(rad/s)
\omega_x_c 66.20 66.30

66.25
\omega_y_c 59.10 53.80

56.45
\omega_z_c 44.25 41.50

42.87

In Metriks, the “Avg of CSDM and MPS” are used for the Takhounts risk curves, and “MPS Based” for Laituri risk curves.

4. Obtain risk of AIS head injury by plugging calculated BrIC scores into the following equations, chosen by the user:

a. Takhounts Curves:

    \[\begin{array}{*{20}{c}}{P(AIS1) = 1 - {e^{ - {{\left( {\frac{{BrIC}}{{0.120}}} \right)}^{2.84}}}}}\\{P(AIS2) = 1 - {e^{ - {{\left( {\frac{{BrIC}}{{0.602}}} \right)}^{2.84}}}}}\\{P(AIS3) = 1 - {e^{ - {{\left( {\frac{{BrIC}}{{0.987}}} \right)}^{2.84}}}}}\\{P(AIS4) = 1 - {e^{ - {{\left( {\frac{{BrIC}}{{1.204}}} \right)}^{2.84}}}}}\\ {P(AIS5) = 1 - {e^{ - {{\left( {\frac{{BrIC}}{{1.252}}} \right)}^{2.84}}}}} \end{array}\]

b. Laituri Curves2:

    \[\begin{array}{*{20}{c}} {P(AIS1 + ) = 1 - \left( {\frac{1}{{1 + {e^{ - (6.100 - {{4.251}^{}}BrIC)}}}}} \right)}\\ {P(AIS2 + ) = 1 - \left( {\frac{1}{{1 + {e^{ - (7.022 - {{4.251}^{}}BrIC)}}}}} \right)}\\ {P(AIS3 + ) = 1 - \left( {\frac{1}{{1 + {e^{ - (8.549 - {{4.251}^{}}BrIC)}}}}} \right)} \end{array}\]

 

 

 

References

[1] Takhounts E.G, Craig M.J., Moorhouse K., McFadden J. (2013). Development of Brain Injury Criteria. Stapp Car Crash J. (57) pp. 243-266.

[2] Laituri T.R., Henry S., Pline K., Li G., Frankstein M., Weerappuli P. (2016) New Risk Cruves for NHTSA’s Brain Injury Criterion (BrIC): Derivations and Assessments. Stapp Car Crash J. (60): pp. 301-362