Browsing by Author "Moorhouse, Kevin Michael"

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    Determination of a Whiplash Injury Severity Estimator (WISE Index) for Occupants in a Motor Vehicle Accident
    Moorhouse, Kevin Michael (Virginia Tech, 1998-04-21)
    The diagnosis of a whiplash injury is a very subjective process. A claim of this type of injury is usually made on the basis of pain, which may or may not be accompanied by clinical signs of trauma. This study was aimed at providing a more objective, quantitative approach to identifying the potential for whiplash injury in a directfront-or-rear-end automobile collision. The Whiplash Injury Severity Estimator (WISE Index) was created using data obtained from Dr. Schneck's personal library of case files, including the collisionacceleration of the vehicle, and the height, weight, and sex of the occupant. Some extrapolated data was also used representing the low and high ranges of height, weight, and collision acceleration to increase the range of the WISE Index. Data was analyzed by the Dynaman computer program in conjunction with the Articulated Total Body Model, to calculate the response of the body to external forces and impacts. The dynamic response of the occupant, combined with preexisting medical statistics provided the information necessary to perform a regression analysis in MINITAB and thus construct the WISE Indices shown below. Male WISE Index (R² = 0.993) £ = 0.2643 ± 0.4071 |(accel,g)| -0.01428(PI) <1.1g<=accel<=5g; 22.4<=PI<=25.0 Female WISE Index (R² = 0.978) £ = 0.6214 ± 0.3429 |(accel,g)| -0.02929(PI) 0.8g<=accel<=5g 22.3<=PI<=31.0 Acceleration: Use the negative sign if it is a rear-end collision and the positive sign if it is a head-on collision. £ : A negative value means that potential injury results from backward head rotation, as in a rear-end collision. A positive value means that potential injury results from forward head rotation, as in a head-on collision. |£ | < 1 = " Safe " |£ | > 1 = " Dangerous " The WISE Index allows one to predict the potential for a whiplash injury, as well as the intensity of the injury, based solely on collision acceleration, height, weight, and sex of the occupant. It is anticipated that this work and future efforts in this area will provide the information base necessary for anyone to effectively evaluate the validity of an alleged whiplash injury.
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    Role of Intrinsic and Reflexive Dynamics in the Control of Spinal Stability
    Moorhouse, Kevin Michael (Virginia Tech, 2005-09-30)
    Spinal stability describes the ability of the neuromuscular system to maintain equilibrium in the presence of kinematic and control variability, and may play an important role in the etiology of low-back disorders (LBDs). The primary mechanism for the neuromuscular control of spinal stability is the recruitment and control of active paraspinal muscle stiffness (i.e., trunk stiffness). The two major components of active muscle stiffness include the immediate stiffness contribution provided by the intrinsic stiffness of actively contracted muscles, and the delayed stiffness contribution provided by the reflex response. The combined behavior of these two components of active muscle stiffness is often referred to as "effective stiffness". In order to understand the neuromuscular control of spinal stability, stochastic system identification methods were utilized and nonparametric impulse response functions (IRFs) calculated in three separate studies in an effort to: 1) Quantify the effective dynamics (stiffness, damping, mass) of the trunk Nonparametric IRFs were implemented to estimate the dynamics of the trunk during active voluntary trunk extension exertions. IRFs were determined from the movement following pseudo-random stochastic force disturbances applied to the trunk. Results demonstrated a significant increase in effective stiffness and damping with voluntary exertion forces. 2) Quantify the reflex dynamics of the trunk Nonparametric IRFs were computed from the muscle electromyographic (EMG) reflex response following a similar pseudo-random force disturbance protocol. Reflexes were observed with a mean response delay of 67 msec. Reflex gain was estimated from the peak of the IRF and increased significantly with exertion effort. 3) Separate the intrinsic and reflexive components of the effective dynamics and determine the relative role of each in the control of spinal stability. Both intrinsic muscle and reflexive components of activation contribute to the effective trunk stiffness. To evaluate the relative role of these components, a nonlinear parallel-cascade system identification procedure was used to separate the intrinsic and reflexive dynamics. Results revealed that the intrinsic dynamics of the trunk alone can be insufficient to counteract the destabilizing effects of gravity. This illustrates the extreme importance of reflexive feedback in the maintenance of spinal stability and warrants the inclusion of reflexes in any comprehensive trunk model.