The impact of different lenses on visual and musculoskeletal complaints in VDU workers with work-related neck complaints : a randomized controlled trial

Objectives: The impact of wearing lenses on visual and musculoskeletal complaints in VDU workers is currently unknown. The goal of this study was 1) to evaluate the impact of wearing VDU lenses on visual fatigue and self-reported neck pain and disability, compared to progressive lenses, and 2) to measure the effect of both lenses on head inclination and pressure pain thresholds during the performance of a VDU task. Methods: Thirty-five eligible subjects were randomly assigned to wear progressive VDU lenses (VDU group) (n = 18) or progressive lenses (P group) (n = 17). They were enquired about visual complaints (VFQ), self-perceived pain (NRS) and disability (NDI) at baseline (with old lenses), and 1 week, 3 months and 6 months after wearing their new lenses. In addition, Forward Head Angle (FHA) and PPTs were assessed during and after a VDU task before and 6 months after wearing the new lenses. A short questionnaire concerning the satisfaction about the study lenses was completed at the end of the study. Results: In both groups, visual fatigue and neck pain was decreased at 3 and 6 months follow up, compared to baseline. All PPTs were higher during the second VDU task, independent of the type of lenses. The VDU group reported a significantly higher suitability of the lenses for VDU work. Conclusion: It can be concluded that there is little difference in effect of the different lenses on visual and musculoskeletal comfort. Lenses should be adjusted to the task-specific needs and habits of the participant

Neurobiological Divergence of the Positive and Negative Schizophrenia Subtypes Identified on a New Factor Structure of Psychopathology Using Non-negative Factorization:An International Machine Learning Study

ObjectiveDisentangling psychopathological heterogeneity in schizophrenia is challenging and previous results remain inconclusive. We employed advanced machine-learning to identify a stable and generalizable factorization of the “Positive and Negative Syndrome Scale (PANSS)”, and used it to identify psychopathological subtypes as well as their neurobiological differentiations.MethodsPANSS data from the Pharmacotherapy Monitoring and Outcome Survey cohort (1545 patients, 586 followed up after 1.35±0.70 years) were used for learning the factor-structure by an orthonormal projective non-negative factorization. An international sample, pooled from nine medical centers across Europe, USA, and Asia (490 patients), was used for validation. Patients were clustered into psychopathological subtypes based on the identified factor-structure, and the neurobiological divergence between the subtypes was assessed by classification analysis on functional MRI connectivity patterns.ResultsA four-factor structure representing negative, positive, affective, and cognitive symptoms was identified as the most stable and generalizable representation of psychopathology. It showed higher internal consistency than the original PANSS subscales and previously proposed factor-models. Based on this representation, the positive-negative dichotomy was confirmed as the (only) robust psychopathological subtypes, and these subtypes were longitudinally stable in about 80% of the repeatedly assessed patients. Finally, the individual subtype could be predicted with good accuracy from functional connectivity profiles of the ventro-medial frontal cortex, temporoparietal junction, and precuneus.ConclusionsMachine-learning applied to multi-site data with cross-validation yielded a factorization generalizable across populations and medical systems. Together with subtyping and the demonstrated ability to predict subtype membership from neuroimaging data, this work further disentangles the heterogeneity in schizophrenia

Superficial and deep scapulothoracic muscle electromyographic activity during elevation exercises in the scapular plane

STUDY DESIGN: Controlled laboratory study. BACKGROUND: In scapular rehabilitation training, exercises that include a humeral elevation component in the scapular plane are commonly implemented. While performing humeral elevation, the scapula plays an important role, as it has to create a stable basis for the glenohumeral joint. However, a comparison of both deep and superficial muscle activity of the scapula between different types of elevation exercises is lacking and would be helpful for the clinician in choosing exercises. OBJECTIVES: To evaluate scapulothoracic muscle activity during different types of elevation exercises in the scapular plane. METHODS: Scapulothoracic muscle activity was measured in 21 healthy subjects, using fine-wire electromyography in the levator scapulae, pectoralis minor, and rhomboid major muscles and surface electromyography in the upper trapezius, middle trapezius, lower trapezius, and serratus anterior muscles. Measurements were conducted while the participants performed the following elevation tasks in the scapular plane: scaption (elevation in the scapular plane), towel wall slide, and elevation with external rotation (Thera-Band). The exercises were performed without and with additional load. Possible differences between the exercises and the load were studied with a linear mixed model. RESULTS: Performing elevation in the scapular plane with an external-rotation component resulted in higher middle trapezius and lower trapezius activity compared to the scaption and wall slide exercises. The upper trapezius was maximally activated during scaption. The pectoralis minor and serratus anterior showed the highest activity during the towel wall slide. The towel wall slide activated the retractors to a lesser degree (middle trapezius, lower trapezius, levator scapulae, rhomboid major). Adding load resulted in higher muscle activity in all muscles, with some muscles showing a different activation paern between the elevation exercises, depending on the load condition. CONCLUSION: Scaption maximally activated the upper trapezius. The addition of an extra external-rotation component may be used when the goal is to activate the lower trapezius and middle trapezius. The towel wall slide exercise was found to increase pectoralis minor activity. Adding load resulted in higher muscle activity. Some muscles showed a different activation paern between the elevation exercises, depending on the loading condition. The findings of this study give information about which elevation exercises a clinician can choose when the aim is to facilitate specific muscle scapulothoracic activity