BackgroundDual-axis swallowing accelerometry has recently been proposed as a tool for non-invasive analysis of swallowing function. Although swallowing is known to be physiologically modifiable by the type of food or liquid (i.e., stimuli), the effects of stimuli on dual-axis accelerometry signals have never been thoroughly investigated. Thus, the objective of this study was to investigate stimulus effects on dual-axis accelerometry signal characteristics. Signals were acquired from 17 healthy participants while swallowing 4 different stimuli: water, nectar-thick and honey-thick apple juices, and a thin-liquid barium suspension. Two swallowing tasks were examined: discrete and sequential. A variety of features were extracted in the time and time-frequency domains after swallow segmentation and pre-processing. A separate Friedman test was conducted for each feature and for each swallowing task.ResultsSignificant main stimulus effects were found on 6 out of 30 features for the discrete task and on 5 out of 30 features for the sequential task. Analysis of the features with significant stimulus effects suggested that the changes in the signals revealed slower and more pronounced swallowing patterns with increasing bolus viscosity.ConclusionsWe conclude that stimulus type does affect specific characteristics of dual-axis swallowing accelerometry signals, suggesting that associated clinical screening protocols may need to be stimulus specific.

In this poster, we describe a method for using grounded theory and modeling to support collaborative design of social robots for the elderly. Robotic technologies are being designed to assist people in their everyday lives in various ways: as companions [9], domestic helpers [4], receptionists [1], and educational aids [8]. In response to the steadily rising average age of the population in the US, Europe, and Japan, the elderly are often designated as an appropriate audience for assistive robotic technologies. Designing robots for the elderly poses a variety of social challenges—understanding the specific needs and desires of the elderly, supporting independence and human dignity, and making sure that technologies can be successfully incorporated into existing social and physical environments, or “elder ecologies” [3]. These challenges suggest that designing robots for the elderly calls for attention to individual attitudes towards technologies as well as community norms and practices of social interaction and technology use.

Fast Hermite projections have been often used in image-processing procedures such as image database retrieval, projection filtering, and texture analysis. In this paper, we propose an innovative approach for the analysis of one-dimensional biomedical signals that combines the Hermite projection method with time-frequency analysis. In particular, we propose a two-step approach to characterize vibrations of various origins in swallowing accelerometry signals. First, by using time-frequency analysis we obtain the energy distribution of signal frequency content in time. Second, by using fast Hermite projections we characterize whether the analyzed time-frequency regions are associated with swallowing or other phenomena (vocalization, noise, bursts, etc.). The numerical analysis of the proposed scheme clearly shows that by using a few Hermite functions, vibrations of various origins are distinguishable. These results will be the basis for further analysis of swallowing accelerometry to detect swallowing difficulties.

BACKGROUND/AIM Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia in general population. The aim of the study was to compare all-cause mortality and cardiovascular mortality in patients with lone and idiopathic AF to correspondent mortality in general population of Serbia. METHODS A longitudinal observational study included the patients with nonvalvular AF as the main indication for in-hospital and/or outpatient treatment in the Clinical Center of Serbia, during a period 1992-2007, if the latest date of first diagnosed AF was early January 2003; in that way, the total follow-up could last at least 5 years (minimum 1 year prospectively), or until death. Principles of oral anticoagulation, heart rhythm and frequency control during the study period were conducted according to the latest international guidelines for diagnosis and treatment of AF in the study period. Lone and idiopathic AF were defined as AF in patients without any underlying disease, younger than 60 years (lone AF) or older (idiopathic AF). To compare mortality of the study population with mortality of general population we used the standardized mortality ratio (SMR) and chi-square test with p < 0.05 as a level of statistical significance. RESULTS Out of 442 patients with AF and no underlying disease, aged 47 +/- 12.6 years, with mean follow-up of 11.5 +/- 7.2 years, 12 patients (2.7%) died: 7 patients of non-cardiovascular causes and 5 patients (1.1%) of cardiovascular death. When compared to the general population of Serbia, all-cause mortality and cardiovascular mortality in the patients with lone and idiopathic AF were not higher than in general population (p < 0.05). CONCLUSION All-cause mortality and cardiovascular mortality of patients with lone and idiopathic AF are similar to all-cause mortality and cardiovascular mortality in general population of Serbia.