OBJECTIVES The objective of this study is to examine the effectiveness of the active head restraint system in reducing neck injury risk of car occupants in low-speed rear impacts. METHODS A human body FE model "THUMS" was used to simulate head and neck kinematics of the occupant and to evaluate loading to the neck. Joint capsule strain was calculated to predict neck injury risk as well as NIC...

Previous studies suggest that stimulation of lateral intraparietal cortex (LIP) evokes saccadic eye movements toward eye- or head-fixed goals, whereas most single-unit studies suggest that LIP uses an eye-fixed frame with eye-position modulations. The goal of our study was to determine the reference frame for gaze shifts evoked during LIP stimulation in head-unrestrained monkeys. Two macaques (...

The purpose of this study was to evaluate the relative contributions of inputs from the vestibular system and the trunk to head-trunk coordination. Twelve healthy adults and 6 adults with diminished bilateral labyrinthine input (LD) were seated with their trunk either fixed to the seat or free to move. Subjects received 10-cm, 445-cm/s(2) anterior-posterior ramps and 0.35- to 4.05-Hz sum-of-sin...

INTRODUCTION It is known that a well-fixed stem can be left in situ when only the acetabular component and femoral head have to be changed. However, in a revision case, the use of a ceramic head on an existing taper is not recommended. Slight damages of the taper may increase the risk of a ceramic fracture. Until now in a revision case a primary ceramic-on-ceramic or ceramic-on-polyethylene pai...

The authors describe the case of a 37-year-old patient who sustained a subcapital femoral neck fracture six months after ICLH double-cup hip resurfacing. As the polyethylene acetabular resurfacing component was undamaged and well fixed, a standard femoral stem with a bipolar head was inserted. The outer diameter of the bipolar head was chosen to fit the resurfacing socket. The "tripolar" hip ar...

When the head is unrestrained, rapid displacements of the visual axis-gaze shifts (eye-re-space)-are made by coordinated movements of the eyes (eye-re-head) and head (head-re-space). To address the problem of the neural control of gaze shifts, we studied and contrasted the discharges of omnipause neurons (OPNs) during a variety of combined eye-head gaze shifts and head-fixed eye saccades execut...

BACKGROUND When stimuli are presented over headphones, they are typically perceived as internalized; i.e., they appear to emanate from inside the head. Sounds presented in the free-field tend to be externalized, i.e., perceived to be emanating from a source in the world. This phenomenon is frequently attributed to reverberation and to the spectral characteristics of the sounds: those sounds who...

Methods: Twelve healthy individuals were recruited. The target consisted of a red fixation cross against a grid patternataviewingdistanceof33cm.Thetargetwasmounted onawall(earthfixed)orwascoupledtothehead(headfixed). Changes in mean torsional eye position were plotted as a function of head position steps (0°±25° in 5° steps), and sigmoidal fits were performed. Mean static OCR gain was calculate...

Projection-based visual display systems are expected to be effective platforms for VR applications, in which the displayed images are generated by computer graphics using three-dimensional models of virtual worlds. However, these kinds of visual displays, as well as other kinds of fixed-screen-based displays such as various head-tracked displays (HTD) and conventional CRT displays, have not bee...