Eye-Hand Coordination Assessment Metrics Using a Multi-Platform Haptic System with Eye-Tracking and Motion Capture Feedback.

In this paper, we discuss the possibility to determine assessment metrics for eye-hand coordination, using a mapping between a robotic haptic device to a virtual environment, and correlating it with the eye-gaze and upper arm movements. Our goal is to develop, implement and refine a system that will assess and improve eye-hand coordination in individuals with disabilities. A detailed analysis of patterns was conducted by therapists in order to select various levels of difficulty that could be included in the system, and which would yield the greatest benefit in terms of assessment of coordination as well as in training. Participants were instructed to use a haptic device (Omni) to follow the trajectories. This was completed while video data were collected using a Vicon motion capture system. Readings of traced trajectories, time, and upper limb motions were recorded for further analysis. One of the patterns was chosen to develop a multi-platform haptic system to be virtually rendered with any haptic device and a Graphic User Interface (GUI) with options to guide the user along the chosen pattern using a haptic tunnel calculated by using B-splines. Two types of haptic tunnels are presented and evaluated: one that follows the mid path of the pattern, and one that takes the smoothest path through the pattern. Finally, the Pearson coefficient was chosen as a metric to correlate the haptic device and the eye-gaze coordinates recorded simultaneously while the user traces a path.

Intra-operative measurement of tumour size in breast cancer and its comparison with other methods: a prospective study.

UNLABELLED: Accurate measurement of breast tumour size determines staging and prognosis. Discrepancies amongst clinical examination (CE), ultrasonography (USG), mammography, pathological examination (PE) and magnetic resonance imaging have been reported. However, few studies have evaluated changes in breast tumour size from the operating table to the laboratory. OBJECTIVES AND METHODS: A prospective study was designed to assess the intra-operative (IO) tumour size in 29 patients of breast cancer presenting to a tertiary care centre in Delhi and to compare it with CE, USG and PE. OBSERVATIONS AND RESULTS: Twenty-nine patients (mean age: 47 years), presenting with invasive duct carcinoma (stage IIIA: 31%, stage IIB: 28%), were included in the study. Comparison with mean IO (4.2 cm) revealed that both USG and PE underestimated tumour size by a mean of 0.35 cm (8.4%) and 0.45 cm (10.7%), respectively, in most patients. CE tended to overestimate size by 0.82 cm (19.8%). All three modalities showed statistically significant correlation with IO (maximum Pearson's correlation coefficient for PE=0.937, p<0.001; R(2)=0.877, maximum for PE). Two-way analysis of variance revealed mean difference in size to be statistically significant (p=0.000) only between CE and IO. DISCUSSION: Formalin processing causes changes in tumour dimensions in the breast, causing reduction in tumour size. It may also have a bearing on the assessment of surgical margins in breast conservation surgery. Immediate post-operative measurement of the specimen is ideal. Protocols for specimen fixation should be standardized.

Body positions used by healthy and frail older adults to rise from the floor.

OBJECTIVE: The purpose of this study was to describe how older adults, particularly more physically impaired older adults, might differ from healthy controls in the body positions used to rise from the floor. DESIGN: Cross-sectional analysis of young, healthy older, and congregate housing older women. SETTING: University-based laboratory and congregate housing facility. PARTICIPANTS: Healthy young university student controls (n = 22, mean age 23 years); healthy old adults living independently in the community (n = 24, mean age 73 years); and congregate housing older adults (n = 29, mean age 81 years). INTERVENTION: Videotaping and timing of rising from a supine position on the floor to standing. MAIN OUTCOME MEASURES: In addition to the time taken to rise from the floor, 10 specific trunk and extremity positions used during the rise, termed Intermediate Positions (IP), were identified. RESULTS: The Young controls had the fastest rise time and used the fewest number of IP, whereas the Congregate residents had the slowest rise time and used the most IP, with the Healthy old adults intermediate in both time and IP use. Prevalence of certain IP, together with correlational and factor analyses, suggest that use of Sit and Crouch was the most preferred rise strategy for the Young controls, whereas use of Tuck, Crouch-Kneel, All Fours, and Bearwalk was the most preferred rise strategy among the Congregate residents. The Healthy old used IP common to both Young and Congregate residents, reflecting a rise strategy intermediate to the latter groups. A substantial subset of the Congregate residents (38%) were unable to rise without assistance and appeared to use certain preparatory positions (Sit, Kneel, Tuck) but were unable to get into presumably more challenging positions (Crouch-Kneel, All Fours, Bearwalk). CONCLUSIONS: With increasing age and physical impairment, body positions used during rising from the floor suggest a preference for maintaining upper and lower extremity contact with the floor, presumably minimizing the lower extremity strength requirements to rise and maximizing stability and postural control. These intermediate body positions may be useful as the basis for training older adults to rise from the floor.

Wavelet based multiresolution expectation maximization image reconstruction algorithm for positron emission tomography.

Maximum Likelihood (ML) estimation based Expectation Maximization (EM) [IEEE Trans Med Imag, MI-1 (2) (1982) 113] reconstruction algorithm has shown to provide good quality reconstruction for positron emission tomography (PET). Our previous work [IEEE Trans Med Imag, 7(4) (1988) 273; Proc IEEE EMBS Conf, 20(2/6) (1998) 759] introduced the multigrid (MG) and multiresolution (MR) concept for PET image reconstruction using EM. This work transforms the MGEM and MREM algorithm to a Wavelet based Multiresolution EM (WMREM) algorithm by extending the concept of switching resolutions in both image and data spaces. The MR data space is generated by performing a 2D-wavelet transform on the acquired tube data that is used to reconstruct images at different spatial resolutions. Wavelet transform is used for MR reconstruction as well as adapted in the criterion for switching resolution levels. The advantage of the wavelet transform is that it provides very good frequency and spatial (time) localization and allows the use of these coarse resolution data spaces in the EM estimation process. The MR algorithm recovers low-frequency components of the reconstructed image at coarser resolutions in fewer iterations, reducing the number of iterations required at finer resolution to recover high-frequency components. This paper also presents the design of customized biorthogonal wavelet filters using the lifting method that are used for data decomposition and image reconstruction and compares them to other commonly known wavelets.

Limited contact dynamic compression in diaphyseal fractures of the humerus: good outcome in 51 patients.

We reviewed 51 plate fixations for fracture of the humeral diaphysis managed during the last 3 years. The indications for surgery included non-union, delayed union, polytrauma, neurological involvement and inadequate reduction. All the fractures were stabilized with a Limited Contact Dynamic Compression Plate (LCDC Plate). We found that this plate gave adequate rotational and vertical stability to the fracture. 48 fractures healed after median 2.5 months. Early evidence of callus formation indicated minimal compromise with the vascularity of bone which may be attributed to the undercut design of the plate, causing relatively less cortical ischemia. In addition, the plate fixation was associated with fewer complications, as compared to those reported with intramedullary nailing.

Colles' fracture: management by percutaneous crossed-pin fixation versus plaster of Paris cast immobilization.

Colles' fracture is the most common fracture seen in orthopedic practice, but no consensus has been reached on an effective method to maintain the initial reduction achieved. This prospective, randomized study of 50 patients evaluates the efficacy of maintaining reduction and consequent functional end results of two treatment methods, ie, percutaneous crossed-pin fixation followed by plaster of Paris cast immobilization with the wrist in functional position versus conventional plaster of Paris cast immobilization. The anatomical and functional end results were significantly better with percutaneous crossed-pin fixation at final follow-up.

SPECT electronic collimation resolution enhancement using chi-square minimization.

An electronic collimation technique is developed which utilizes the chi-square goodness-of-fit measure to filter scattered gammas incident upon a medical imaging detector. In this data mining technique, Compton kinematic expressions are used as the chi-square fitting templates for measured energy-deposition data involving multiple-interaction scatter sequences. Fit optimization is conducted using the Davidon variable metric minimization algorithm to simultaneously determine the best-fit gamma scatter angles and their associated uncertainties, with the uncertainty associated with the first scatter angle corresponding to the angular resolution precision for the source. The methodology requires no knowledge of materials and geometry. This pattern recognition application enhances the ability to select those gammas that will provide the best resolution for input to reconstruction software. Illustrative computational results are presented for a conceptual truncated-ellipsoid polystyrene position-sensitive fibre head-detector Monte Carlo model using a triple Compton scatter gamma sequence assessment for a 99mTc point source. A filtration rate of 94.3% is obtained, resulting in an estimated sensitivity approximately three orders of magnitude greater than a high-resolution mechanically collimated device. The technique improves the nominal single-scatter angular resolution by up to approximately 24 per cent as compared with the conventional analytic electronic collimation measure.

Analytic treatment of resolution precision in electronically collimated SPECT imaging involving multiple-interaction gamma rays.

The widely applied single-interaction analytic expression characterizing the energy resolution component of the angular resolution precision for an electronically collimated point source is extended to include multiple-interaction Compton scatter sequences as well as sequences terminated by photoelectric absorption. The analytic formulation is developed using the statistical variance of the mean for components comprising composite, multivariate resolution precision estimators. It is demonstrated that enhanced resolution precision in the incident interaction scatter angle is attained when use is made of information from multiple interactions. An improvement in the resolution precision of up to approximately 40% is observed for triple Compton scatter. Comparison of the analytic estimates with Monte Carlo/chi-square results shows good agreement.

Rising from the floor in older adults.

OBJECTIVE: The primary goal was to determine the ability of older adults to rise from the floor. A secondary goal was to explore how rise ability might differ based on initial body positions and with or without the use of an assistive device. DESIGN: Cross-sectional analysis of young, healthy older, and congregate housing older adults. SETTING: University-based laboratory and congregate housing facility. PARTICIPANTS: Young adult controls (12 men and 12 women, mean age 23 years), healthy older adults (12 men and 12 women, mean age 73 years), and congregate housing older adults (32 women and 6 men, mean age 80 years). The healthy older adult women (n = 12, mean age 75 years) and a subset of the congregate housing women (n = 27, mean age 81 years) were identified for further analyses. INTERVENTION: Videotaping and timing of rising from the floor from controlled initial body positions (supine, on side, prone, all fours, and sitting) and with or without the use of a furniture support. MAIN OUTCOME MEASURES: Whether subjects were successful in rising, and if they were, the time taken to rise. Subjects also rated their perceived difficulty of the task as compared to the reference task, rising from a supine position. RESULTS: Older adults have more difficulty rising from the floor than younger adults. The healthy old took twice as long as the young to rise, whereas the congregate old took two to three times as long as the healthy old to rise. Although all young and healthy old rose from every position, a subset of the congregate housing residents was unable to rise from any position, 24% when attempting to rise without a support and 13% when attempting to rise with a support. Congregate old were most likely to be successful when rising from a side-lying position while using the furniture for support. The more able congregate old, as well as the young and healthy old, rose more quickly and admitted to the least difficulty when rising from the all fours position. CONCLUSIONS: The inability to rise from the floor is relatively common in congregate housing older adults. Based on the differences between groups in time to complete the rise, determining the differences in rise strategies, and the underlying biomechanical requirements of rising from different positions with or without a support would appear to be useful. These data may serve as the foundation for future interventions to improve the ability to rise from the floor.

Verrucous carcinoma of the endocervix.

The case report of a 79-year-old woman with the histologic features of verrucous squamous cell carcinoma of the uterus is presented. The case is unusual because the characteristic exophytic lesion of verrucous squamous cell carcinoma was not visible in this patient, as the entire lesion was confined to the endocervical and endometrial cavities. The diagnosis was made by fractional dilatation and curettage in the evaluation of postmenopausal bleeding. The characteristic clinical and pathological features of verrucous carcinoma are discussed. The etiologic agent and appropriate treatment of this lesion are outlined.