Exploring the receptor origin of vibration-induced reflexes

STUDY DESIGN: An experimental design. OBJECTIVES: The aim of this study was to determine the latencies of vibration-induced reflexes in individuals with and without spinal cord injury (SCI), and to compare these latencies to identify differences in reflex circuitries. SETTING: A tertiary rehabilitation center in Istanbul. METHODS: Seventeen individuals with chronic SCI (SCI group) and 23 participants without SCI (Control group) were included in this study. Latency of tonic vibration reflex (TVR) and whole-body vibration-induced muscular reflex (WBV-IMR) of the left soleus muscle was tested for estimating the reflex origins. The local tendon vibration was applied at six different vibration frequencies (50, 85, 140, 185, 235, and 265 Hz), each lasting for 15 s with 3-s rest intervals. The WBV was applied at six different vibration frequencies (35, 37, 39, 41, 43, and 45 Hz), each lasting for 15 s with 3-s rest intervals. RESULTS: Mean (SD) TVR latency was 39.7 (5.3) ms in the SCI group and 35.9 (2.7) ms in the Control group with a mean (95% CI) difference of -3.8 (-6.7 to -0.9) ms. Mean (SD) WBV-IMR latency was 45.8 (7.4) ms in the SCI group and 43.3 (3.0) ms in the Control group with a mean (95% CI) difference of -2.5 (-6.5 to 1.4) ms. There were significant differences between TVR latency and WBV-IMR latency in both the groups (mean (95% CI) difference; -6.2 (-9.3 to -3.0) ms, p = 0.0001 for the SCI group and -7.4 (-9.3 to -5.6) ms, p = 0.011 for Control group). CONCLUSIONS: The results suggest that the receptor of origin of TVR and WBV-IMR may be different

EM based Stochastic maximum likelihood approach for localization of near-field sources in 3-D

The goal of this paper is to estimate the locations of unknown sources in 3-D space from the data collected by a 2-D rectangular array. Various studies employing different estimation methods under near-field and far-field assumptions were presented in the past. In most of the previous studies, location estimations of sources at the same plane with the antenna array were carried out by using algorithms having constraints for various situations indeed. In this study, location estimations of sources that are placed at a different plane from the antenna array is given. In other words, locations of sources in 3-D space is estimated by using a 2-D rectangular array. Maximum likelihood (ML) method is chosen as the estimator since it has a better resolution performance than the conventional methods in the presence of less number and highly correlated source signal samples and low signal to noise ratio. Besides these superiorities, stability, asymptotic unbiasedness, asymptotic minimum variance properties as well as no restrictions on the antenna array are motivated the application of ML approach. Despite these advantages, ML estimator has computational complexity. However, this problem is tackled by the application of Expectation/Maximization (EM) iterative algorithm which converts the multidimensional search problem to one dimensional parallel search problems in order to prevent computational complexity. EM iterative algorithm is therefore adapted to the localization problem by the data (complete data) assumed to arrive to the sensors separately instead of observed data (incomplete data). Furthermore, performance of the proposed algorithm is tested by deriving Cramer-Rao bounds based on the concentrated likelihood approach. Finally, the applicability and effectiveness of the proposed algorithm is illustrated by some numerical simulations

Deterministic maximum likelihood approach for 3-D near field source localization

In this paper, maximum likelihood estimator is proposed for passive localization of narrowband sources in the spherical coordinates (azimuth, elevation, and range). We adapt Expectation/Maximization iterative method to solve the complicated multi-parameter optimization problem appearing on the 3-D localization problem. The proposed algorithm is based on maximum likelihood criterion which employs the source signals recorded by 2-D array under near-field assumption. Expectation/Maximization algorithm decomposes the observed data into its components and then estimates the parameters of each signal component separately providing computationally efficient solution to the resulting optimization problem. Performance analysis of the proposed algorithm is then carried out through the evaluation of Cramer-Rao bounds. Finally, the applicability and effectiveness of the proposed algorithm is illustrated by some numerical simulations

The use of hydrotherapy for the management of spasticity

Introduction. Spasticity is a major problem for the rehabilitation team. Physiotherapy is a vital component of therapy. Oral medication and other modalities such as beat, cold, ultrasound, electrical stimulation, and surgery (neurosurgical or orthopedic) can also be used. The aim of this study was to compare the effects of hydrotherapy on spasticity and Functional Independence Measure (FIM) scores of patients with spinal cord injury (SCI). Materials and Methods. This is a control case matched study. Twenty SCI patients were divided into 2 groups and matched for age, gender, injury time, Ashworth scores, oral baclofen intake, American Spinal Injury Association, and FIM scores. The control group received passive range of motion exercise twice a day and oral baclofen for 10 weeks. The study group also received passive range of motion and oral baclofen, as well as 20 min of water exercises (at 71degreesF full immersion) 3 times per week. The authors evaluated spasm severity, FIM scores, oral baclofen intake, and Ashworth scales, between groups at the beginning and at the end of the treatment Period. Results. Both groups demonstrated a significant increase in FIM scores. However, the hydrotherapy group demonstrated a larger increase (P < 0.0001) than the control group. There was a statistically significant decrease in oral baclofen intake in the hydrotherapy group (P < 0.01). There was no statistical change in the control group. Spasticity was evaluated by the Ashworth scale. There was a statistical improvement in each group (P < 0.01 P < 0.02). However, when compared to the control group, the use of hydrotherapy produced a significant decrease in spasm severity (P < 0.02). Conclusion. Side effects are often seen when using oral drug treatment for spasticity. Adding hydrotherapy to the rehabilitation program can be helpful in decreasing the amount of medication required. Future studies must evaluate benefits of hydrotherapy for rehabilitation