Validation of foot pitch angle estimation using inertial measurement unit against marker-based optical 3D motion capture system

Gait analysis is relevant to a broad range of clinical applications in areas of orthopedics, neurosurgery, rehabilitation and the sports medicine. There are various methods available for capturing and analyzing the gait cycle. Most of gait analysis methods are computationally expensive and difficult to implement outside the laboratory environment. Inertial measurement units, IMUs are considered a promising alternative for the future of gait analysis. This study reports the results of a systematic validation procedure to validate the foot pitch angle measurement captured by an IMU against Vicon Optical Motion Capture System, considered the standard method of gait analysis. It represents the first phase of a research project which aims to objectively evaluate the ankle function and gait patterns of patients with dorsiflexion weakness (commonly called a “drop foot”) due to a L5 lumbar radiculopathy pre- and post-lumbar decompression surgery. The foot pitch angle of 381 gait cycles from 19 subjects walking trails on a flat surface have been recorded throughout the course of this study. Comparison of results indicates a mean correlation of 99.542% with a standard deviation of 0.834%. The maximum root mean square error of the foot pitch angle measured by the IMU compared with the Vicon Optical Motion Capture System was 3.738° and the maximum error in the same walking trail between two measurements was 9.927°. These results indicate the level of correlation between the two systems.

Prevalence and risk factors for helicobacter pylori infection among Yemeni dyspeptic patients

Helicobacter pylori [H. pylori] is one of the world's most common human bacterial infections. Acquisition of H. pylori infection may be associated with chronic gastritis, peptic ulceration and gastric cancer. This study was aimed at investigating the prevalence of H. pylori infection among dyspeptic patients, any correlation with dyspeptic symptoms and endoscopic findings and, any socioeconomic and environmental risk factors. The study was conducted between September 1997 and October 1998 in one Endoscopy Unit, Sana'a city, Yemen. A total of 275 consecutive patients with chronic dyspepsia were enrolled in the study. Endoscopic examination was conducted, gastric biopsies were obtained from the antrum and corpus, and H. pylori infection was diagnosed at the time of endoscopy using the rapid urease test. The prevalence of H. pylori infection in our patients was 82.2% [95% confidence interval [CI] 78 to 87%]. Independent variables associated with infection were age >40 years [odds ration [OR]=2.2; 95% CI: 1.0-4.64; P=0.043]; the presence of >= 5 children under 14 years per household [OR=6.62; 95% CI: 2.245 to 19.5; P= 0.001]; and duodenal ulcer disease [OR=3.7; 95% CI: 1.38 to 10.0; P=0.009]. The prevalence of H. pylori infection in dyspeptic patients in Yemen seems to be high. Advancing age, 5 or more children per household and duodenal ulcer disease were found to be significantly associated with H. pylori infection