The most recent study investigated mTBI injury risk as a function of linear acceleration alone, rotational acceleration alone, and a combination of both linear and rotational acceleration using logistic regression (Rowson and Duma, 2013).
Inside each end organ are the hair cells, the detection units for both linear and angular acceleration.
The authors argued that the combined model was preferred for future investigations because it incorporated both linear and rotational acceleration and because real-world head impacts always involve a combination of the two.
A force that does not pass through the CG (i.e. impact to the high forehead) will produce an impulsive moment (conceptually a 'twisting force') about the CG, which will initiate both linear and rotational acceleration.
Many researchers have proposed metrics that are a combination of both linear and rotational acceleration (and other factors such as HIC and impact force location on the skull) (Gurdjian, 1975; Ono et al., 1980; Pellman et al., 2003; Greenwald et al., 2008; Rowson and Duma, 2013) as the most predictive mechanisms of brain injury (see below).
The two components of the vestibulo-ocular reflex interact, enabling appropriate eye movements to be generated when both linear and angular accelerations are changing.
Peak linear acceleration, angular acceleration and angular velocity were calculated for resultants and all unique directional components.
Linear and angular accelerations and displacements of the head, and linear accelerations of the T1 and pelvis were measured in the sagittal-plane.
The average measured sensitivities of the fabricated sensor for linear accelerations and angular accelerations show a cross-axis sensitivity of <4%.
Otoliths are sensitive to gravity and linear acceleration and play a role in balance.
Rotational and linear acceleration, gravity and sound are sensed by the zebrafish inner ear and lateral line organ [ 44, 45].
