Differences between lower extremity joint running kinetics captured by marker-based and markerless systems were speed dependent

Background:The development of computer vision technology has enabled the use of markerless movement tracking for biomechanical analysis.Recent research has reported the feasibility of markerless systems in motion analysis but has yet to fully explore their utility for capturing faster movements,such as running.Applied studies using markerless systems in clinical and sports settings are still lacking.Thus,the present study compared running biomechanics estimated by marker-based and markerless systems.Given running speed not only affects sports performance but is also associated with clinical injury prevention,diagnosis,and rehabilitation,we aimed to investigate the effects of speed on the comparison of estimated lower extremity joint moments and powers between markerless and marker-based technologies during treadmill running as a concurrent validating study.Methods:Kinematic data from marker-based/markerless technologies were collected,along with ground reaction force data,from 16 young adults running on an instrumented treadmill at 3 speeds:2.24 m/s,2.91 m/s,and 3.58 m/s(5.0 miles/h,6.5 miles/h,and 8.0 miles/h).Sagittal plane moments and powers of the hip,knee,and ankle were calculated by inverse dynamic methods.Time series analysis and statistical parametric mapping were used to determine system differences.Results:Compared to the marker-based system,the markerless system estimated increased lower extremity joint kinetics with faster speed during the swing phase in most cases.Conclusion:Despite the promising application of markerless technology in clinical settings,systematic markerless overestimation requires focused attention.Based on segment pose estimations,the centers of mass estimated by markerless technologies were farther away from the relevant distal joint centers,which led to greater joint moments and powers estimates by markerless vs.marker-based systems.The differences were amplified by running speed.

Voxel-based statistical analysis of regional cerebral glucose metabolism in children with attention-deficit hyperactivity disorder

The technique of region of interest-based positron emission tomography is limited by its poor reli-ability and relatively few examined brain regions. In the present study, we compared brain metabo-lism assessed using fluorine-18-fluorodeoxyglucose positron emission tomography between 14 at-tention-deficit hyperactivity disorder （ADHD） patients and 15 normal controls with scoliosis at resting state by statistical parametric mapping. Glucose metabolism was decreased in the left parahippo-campal gyrus, left hippocampus, left anterior cingulate gyrus, right anterior and posterior lobes of the cerebellum, left superior temporal gyrus, left insula, left medial and middle frontal gyri, right medial frontal gyrus, and left basal ganglia （putamen, amygdala, and caudate nucleus） in children with ADHD. These data suggest that children with ADHD exhibit hypometabolism in various brain regions compared to controls, indicating that ADHD symptoms are unlikely the result of abnormalities in specific areas.

Age-related white matter degradation rule of normal human brain： the evidence from diffusion tensor magnetic resonance imaging

Background Diffusion tensor imaging can evaluate white matter function in human brain.Fractional anisotropy is the most important parameter.This study aimed to find regional reduction of fractional anisotropy （FA） with aging in the whole brain and the changing rules of anisotropy with aging.Methods Fifty volunteers from 20 to 75 years old were divided into five consecutive age groups; a young group and four senior groups.FA values were calculated with diffusion tensor imaging （DTI） studio software.The difference of FA between the young group and the four senior groups were analyzed by analysis of voxel-level height threshold in Statistic Parametric Mapping （SPM）,and the regions with decreased FA were obtained.The FA values of these regions were then extracted using an in-house developed program,and a multiple linear regression model was built to assess the influence of age and sex on the FA values of these regions.Results Eight regions,including frontal lobe,postcentral gyrus,optic radiation,hippocampus,cerebella hemisphere,corona radiate,corpus callosum and internal capsule,were found to have decreased FA.There was a strong negative correlation between age and the FA in the frontal lobe,postcentral gyrus,optic radiation,hippocampus,and cerebella hemisphere,while a weaker negative correlation in the corona radiate,corpus callosum,and internal capsule was found.The FA reduction in the frontal lobe,postcentral gyrus,optic radiation,hippocampus and cerebella hemisphere were found earlier than in the corona radiate,corpus callosum and internal capsule.There was no correlation between sex and FA in these regions.Conclusions The FA in the subcortical white matter area reduces earlier than that in deep white matter.The areas with decreased FA continuously enlarge with aqing.The FAs in these regions have a strong negative correlation with age.

Preliminary Study of Brain Glucose Metabolism Changes in Patients with Lung Cancer of Different Histological Types

Background： Cerebral glucose metabolism changes are always observed in patients suffering from malignant tumors. This preliminary study aimed to investigate the brain glucose metabolism changes in patients with lung cancer of different histological types. Methods： One hundred and twenty patients with primary untreated lung cancer, who visited People＇s Hospital of Zhengzhou University from February 2012 to July 2013, were divided into three groups based on histological types confirmed by biopsy or surgical pathology, which included adenocarcinoma （52 cases）, squamous cell carcinoma （43 cases）, and small-cell carcinoma （25 cases）. The whole body ^18F-fiuorodeoxyglucose （^18F-FDG） positron emission tomography （PET）/computed tomography （CT） of these cases was retrospectively studied. The brain PET data of three groups were analyzed individually using statistical parametric maps （SPM） software, with 50 age-matched and gender-matched healthy controls for comparison. Results： The brain resting glucose metabolism in all three lung cancer groups showed regional cerebral metabolic reduction. The hypo-metabolic cerebral regions were mainly distributed at the left superior and middle frontal, bilateral superior and middle temporal and inferior and middle temporal gyrus. Besides, the hypo-metabolic regions were also found in the right inferior parietal lobule and hippocampus in the small-cell carcinoma group. The area of the total hypo-metabolic cerebral regions in the small-cell carcinoma group （total voxel value 3255） was larger than those in the adenocarcinoma group （total voxel value 1217） and squamous cell carcinoma group （total voxel value 1292）. Conclusions： The brain resting glucose metabolism in patients with lung cancer shows regional cerebral metabolic reduction and the brain hypo-metabolic changes are related to the histological types of lung cancer.