Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference
-
Sternal seismocardiogram (SCG) is the assessment of microvibrations produced by the beating heart as detected by an accelerometer positioned on the sternum. This signal reflects mechanical events of the heart contraction, including the opening and closure of mitral and aortic valves and maximal blood flow acceleration. Traditionally, SCG has been detected in a laboratory setting with the subject lying at rest in supine position. ⋯ A large number of SCG estimates could be obtained over the 24 hours. In particular, more than 100 estimates per hour were available during the day; at night this rate was three times higher. Thus our study indicates that not only the 24h SCG monitoring in daily life is feasible but also that possible changes over time in SCG and its derived parameters may be tracked with an extreme temporal detail.
-
Conf Proc IEEE Eng Med Biol Soc · Jan 2012
Clinical TrialReal-time cardiorespiratory coherence detects antinociception during general anesthesia.
Heart rate variability (HRV) may provide anesthesiologists with a noninvasive tool for monitoring nociception during general anesthesia. A novel real-time cardiorespiratory coherence (CRC) algorithm has been developed to analyze the strength of linear coupling between heart rate (HR) and respiration. CRC values range from 0 (low coherence, strong nociception) to 1 (high coherence, no nociception). ⋯ For comparison, three traditional measures of HRV (LF/HF ratio, SDNN, and RMSSD) responded on average by only 3.8%, 14%, and 3.9%, respectively. Finally, two traditional clinical measures of nociception (HR and blood pressure) responded on average by only 3.9% and 0.91%, respectively. CRC may thus be used as a real-time nociception monitor during general anesthesia.
-
Conf Proc IEEE Eng Med Biol Soc · Jan 2012
Strategies and synergies underlying replacement of vestibular function with prosthetic feedback.
This study investigated changes in movement strategies and muscle synergies when bilateral peripheral vestibular loss (BVL) subjects are provided prosthetic feedback of their pelvis sway during stance. Six BVL subjects performed 3, for them, difficult stance tasks: standing eyes closed, on a firm surface, on a foam surface, and standing eyes open on foam. Movement strategies were recorded as roll and pitch ratios of upper and lower body velocities with body-worn gyroscopes. ⋯ This is the first study that demonstrates how vestibular loss subjects achieve a reduction of sway during stance with prosthetic feedback. Unchanged movement strategies with reduced amplitudes are achieved with reduced antagonistic muscle synergies. This study has implications for the choice of feedback parameters (angle or velocity) and patient groups when using prosthetic devices to reduce sway of those with a tendency to fall.
-
Conf Proc IEEE Eng Med Biol Soc · Jan 2012
Tongue-operated assistive technology with access to common smartphone applications via Bluetooth link.
Tongue Drive System (TDS) is a wireless and wearable assistive technology (AT) that enables people with severe disabilities to control their computers, wheelchairs, and electronic gadgets using their tongue motion. We developed the TDS to control smartphone's (iPhone/iPod Touch) built-in and downloadable apps with a customized Bluetooth mouse module by emulating finger taps on the touchscreen. ⋯ Preliminary results show that the average completion times of a scenario with touch, mouse, and TDS are 165.6 ± 14.50 s, 186.1 ± 15.37 s, and 651.6 ± 113.4 s, respectively, showing that the TDS is 84.37% and 81.16% slower than touch and mouse for speed of typing with negligible errors. Overall, considering the limited number of commands and unfamiliarity of the subjects with the TDS, we achieved acceptable results for hands-free functionality.
-
Conf Proc IEEE Eng Med Biol Soc · Jan 2012
Cortical potential imaging of somatosensory evoked potential induced by mechanical stimulation.
The objective evaluation of somatic sensations is expected without a patient's subjective opinions to reduce social problems such as those related to lawsuits for nerve injuries or malingering. In this study, the somatosensory evoked potential (SEP) using the mechanical stimulations of the tactile sensation was measured and analyzed in spatiotemporal domains. The cortical potential mapping projected onto the realistic-shaped model was estimated to improve the spatial resolution of the SEP maps by application of cortical dipole layer imaging. The experimentally obtained results suggest that the spatiotemporal distributions of the SEPs reflect the differences for positions, strengths, and patterns of somatosensory stimulations.