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Head Rotation (head + rotation)
Selected AbstractsFace as an index: Knowing who is who using a PDAINTERNATIONAL JOURNAL OF IMAGING SYSTEMS AND TECHNOLOGY, Issue 1 2003Jie Yang Abstract In this article, we present a PDA-based system for extending human memory or/and information retrieval using a human face as the lookup index. The system can help a user to remember names of people whom he/she has met before and find useful information, such as names and research interests, about people whom he/she is interested in talking to. The system uses a captured face image as the lookup index to retrieve information from some available resource such as departmental directory, web sites, personal homepages, etc. We describe the development of a PDA-based face recognition system and introduce algorithms for image preprocessing to enhance the quality of the image by sharpening focus and normalizing both lighting condition and head rotation. We use a unified LDA/PCA algorithm for face recognition. We address design issues of the interface to assist in visualization and comprehension of retrieved information. We present user study and experiment results to demonstrate the feasibility of the proposed system. © 2003 Wiley Periodicals, Inc. Int J Imaging Syst Technol 13: 33,41, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ima.10046 [source] Mandibular kinematics associated with simulated low-velocity rear-end impactsJOURNAL OF ORAL REHABILITATION, Issue 8 2006I. A. HERNÁNDEZ summary, Rear-end-impact motor vehicle accidents may result in cervical and temporomandibular-related pain complaints. Head kimematics in simulated low-impact rear-end impacts have been investigated but mandibular kinematics have not been described. Thirty healthy adult subjects underwent three impacts (4·5 m s,2 expected, 10·0 m s,2 unexpected, and 10·0 m s,2 expected). Onset time and peak magnitude of angular head acceleration, angular mandibular acceleration and angular mandibular displacement were measured. Significant mandibular opening acceleration was not identified with rearward head rotation. The peak magnitude of mandibular closing angular acceleration approximately doubled with increased impact magnitude. No differences in peak angular mandibular acceleration regarding expectation were identified. Gender differences were detected in the fast unexpected impact. The peak time for the angular mandibular acceleration (mandibular closure) was approximately 84,120 ms later than peak rearward angular head acceleration for all impacts. Onset and peak times for angular mandibular acceleration (mandibular closure) were similar to the onset and peak times for forward head acceleration. There was also a positive correlation between the magnitude of the forward angular acceleration of the head and angular acceleration of the mandible for the slow (0·65, P = 0·015) and fast expected (0·844, P = 0·001) impacts. The average angular mandibular angular displacement (mandibular closure) was approximately 6°. The hyperextension hypothesis regarding mechanism of temporomandibular joint injury in low-impact rear-end collisions cannot be supported. [source] Shoulder Disability After Different Selective Neck Dissections (Levels II,IV Versus Levels II,V): A Comparative StudyTHE LARYNGOSCOPE, Issue 2 2005Johnny Cappiello MD Abstract Objectives/Hypothesis: The objective was to compare the results of clinical and electrophysiological investigations of shoulder function in patients affected by head and neck carcinoma treated with concomitant surgery on the primary and the neck with different selective neck dissections. Study Design: Retrospective study of 40 patients managed at the Department of Otolaryngology, University of Brescia (Brescia, Italy) between January 1999 and December 2001. Methods: Two groups of 20 patients each matched for gender and age were selected according to the type of neck dissection received: patients in group A had selective neck dissection involving clearance of levels II,IV, and patients in group B had clearance of levels II,V. The inclusion criteria were as follows: no preoperative signs of myopathy or neuropathy, no postoperative radiotherapy, and absence of locoregional recurrence. At least 1 year after surgery, patients underwent evaluation of shoulder function by means of a questionnaire, clinical inspection, strength and motion tests, electromyography of the upper trapezius and sternocleidomastoid muscles, and electroneurography of the spinal accessory nerve. Statistical comparisons of the clinical data were obtained using the contingency tables with Fisher's Exact test. Electrophysiological data were analyzed by means of Fisher's Exact test, and electromyography results by Kruskal-Wallis test. Results: A slight strength impairment of the upper limb, slight motor deficit of the shoulder, and shoulder pain were observed in 0%, 5%, and 15% of patients in group A and in 20%, 15%, and 15% of patients in group B, respectively. On inspection, in group B, shoulder droop, shoulder protraction, and scapular flaring were present in 30%, 15%, and 5% of patients, respectively. One patient (5%) in group A showed shoulder droop as the only significant finding. In group B, muscle strength and arm movement impairment were found in 25% of patients, 25% showed limited shoulder flexion, and 50% had abnormalities of shoulder abduction with contralateral head rotation. In contrast, only one patient (5%) in group A presented slight arm abduction impairment. Electromyographic abnormalities were less frequently found in group A than in group B (40% vs. 85% [P = .003]), and the distribution of abnormalities recorded in the upper trapezius muscle and sternocleidomastoid muscle was quite different: 20% and 40% in group A versus 85% and 45% in group B, respectively. Only one case of total upper trapezius muscle denervation was observed in group B. In both groups, electroneurographic data from the side of the neck treated showed a statistically significant increase in latency (P = .001) and decrease in amplitude (P = .008) compared with the contralateral side. There was no significant difference in electroneurographic data from the side with and the side without dissection in either group. Even though a high number of abnormalities was found on electrophysiological testing, only a limited number of patients, mostly in group B, displayed shoulder function disability affecting daily activities. Conclusion: The study data confirm that clearance of the posterior triangle of the neck increases shoulder morbidity. However, subclinical nerve impairment can be observed even after selective neck dissection (levels II,IV) if the submuscular recess is routinely dissected. [source] Effects of head rotation on the right internal jugular vein in infants and young childrenANAESTHESIA, Issue 3 2010M. J. Gwak Summary We investigated the effects of head rotation on the cross-sectional area of the right internal jugular vein and its relative position to the carotid artery. Eighty-eight subjects were divided into infants and children groups. The cross-sectional area of the right internal jugular vein and the degree of the carotid artery overlap were measured at 0° (neutral), 40° and 80° of head rotation. The cross-sectional area of the right internal jugular vein was significantly larger at 40° and 80° head rotation compared with the neutral position in both infants and children (p < 0.001). As the head was rotated, the percentage overlap of the carotid artery increased significantly (p < 0.001). We suggest that 40° head rotation appears to be optimal for right internal jugular vein cannulation in paediatric patients. [source] Reanimating Faces in Images and VideoCOMPUTER GRAPHICS FORUM, Issue 3 2003V. Blanz This paper presents a method for photo-realistic animation that can be applied to any face shown in a single imageor a video. The technique does not require example data of the person's mouth movements, and the image to beanimated is not restricted in pose or illumination. Video reanimation allows for head rotations and speech in theoriginal sequence, but neither of these motions is required. In order to animate novel faces, the system transfers mouth movements and expressions across individuals, basedon a common representation of different faces and facial expressions in a vector space of 3D shapes and textures. This space is computed from 3D scans of neutral faces, and scans of facial expressions. The 3D model's versatility with respect to pose and illumination is conveyed to photo-realistic image and videoprocessing by a framework of analysis and synthesis algorithms: The system automatically estimates 3D shape andall relevant rendering parameters, such as pose, from single images. In video, head pose and mouth movements aretracked automatically. Reanimated with new mouth movements, the 3D face is rendered into the original images. Categories and Subject Descriptors (according to ACM CCS): I.3.7 [Computer Graphics]: Animation [source] Locomotor skills and balance strategies in children with internal rotations of the lower limbsJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 1 2008Sophie Mallau Abstract The purpose of this study was to investigate the functional effects of a structural deformation, internal rotations (IR) of the lower limbs, on upper body balance strategies used during locomotion in 5,6 year-old and 7,10 year-old children. Balance control was examined in terms of rotation around the longitudinal axis in horizontal plane (yaw) and around the sagittal axis in a frontal plane (roll). Kinematics of foot, pelvis, shoulder, and head rotations were measured with an automatic optical TV image processor and used to calculate angular dispersions and segmental stabilizations. Older children with IR showed a lower gait velocity, particularly in difficult balance conditions than typically developing (TD) children. In younger children, the effect of the local biomechanical deficit remained limited to the lower limbs and did not affect upper body coordination. By contrast, in older children with IR, the development of head stabilization in space was affected. This was demonstrated by an "en bloc" instead of an articulated mode of head-trunk unit systematically adopted by the control group. As pelvic stabilization remains the main reference frame to organize balance control in older children with IR, we conclude that the structural deformity of the legs affect and possibly delay the acquisition of the head stabilization in space strategy. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:117,125, 2008 [source] Impaired modulation of the vestibulo-ocular reflex in Huntington's diseaseMOVEMENT DISORDERS, Issue 1 2004BSc(Hons), Joanne Fielding BA Abstract The vestibulo-ocular reflex (VOR) stabilizes gaze during movement, in conjunction with other afferent information: visual, proprioceptive, and somaesthetic. The reflex can either be augmented or suppressed, depending on visual requirements, and undergoes long-term adaptation to compensate for physical changes in the subject. Importantly, over relatively short periods of time, the VOR should function consistently under the same circumstances. This study examines VOR function in patients with Huntington's disease (HD), with a view to investigating cortical influences on the reflex. Horizontal eye movements were recorded in 9 patients with HD and 7 normal subjects, using the scleral search coil technique, in response to high frequency, unpredictable head rotations imposed manually. To establish base VOR function, recordings were made in darkness, without instruction, before and after wearing ×2 magnifying lenses for a period of 2 hours to adapt the reflex. Recordings were also made before adaptation, while fixating a stationary visual target (VOR augmentation), and while fixating a target moving with the head (VOR suppression). Although results suggest that the VOR is preserved in HD, with relatively normal gain values and appropriate augmentation and suppression of the reflex with visual input, patients were unable to adapt the VOR to altered visual conditions. This represents a novel finding in HD and suggests that cortical structures compromised in HD exert influences on the long-term adaptation of the VOR. © 2003 Movement Disorder Society [source] Characterization of the Vestibulo-Ocular Reflex Evoked by High-Velocity MovementsTHE LARYNGOSCOPE, Issue 7 2004François D. Roy HBSc Abstract Objectives/Hypothesis: The horizontal angular vestibulo-ocular reflex (VOR) plays an important role in stabilizing images on the retina throughout head rotations. Current evidence suggests that the VOR behaves linearly at low velocities and nonlinearly at high velocities. The aim of the research was to evaluate and characterize the normal behavior of the reflex evoked by high-velocity head rotations. Study Design: Case control study. Methods: Manually applied head-thrust movements with peak velocities in the range of 100° to 500°/s and peak accelerations up to 7,000°/s 2 were performed on normal volunteers. These head thrusts were comparable with those described in detail by Halmagi and coworkers. Eye and head movements were recorded using the magnetic search coil method. Results: The gain of the VOR is linear at low velocities and saturates at head velocities greater than 350°/s. The values for the normal gain of the reflex were approximated by means of the area between two nonlinear functions. The directional difference parameter, exploring the symmetry of the reflex, indicated that the VOR in normal subjects is symmetric. Conclusion: The gain of the VOR in individuals with intact vestibular function is nonlinear at high angular head velocities. We propose a quantitative means using two nonlinear functions to characterize the normal range of values for the gain of the VOR in individuals with normal vestibular function. A directional difference parameter used in conjunction with the normal range of gains can detect small differences in the symmetry of the VOR and, consequently, reveal unilateral vestibular loss. [source] | ||||||||||