Effect of Sensory Feedback from the Proximal Upper Limb on Voluntary Isometric Finger Flexion and Extension in Hemiparetic Stroke Subjects

This study investigated the potential influence of proximal sensory feedback on voluntary distal motor activity in the paretic upper limb of hemiparetic stroke survivors and the potential effect of voluntary distal motor activity on proximal muscle activity. Ten stroke subjects and 10 neurologically intact control subjects performed maximum voluntary isometric flexion and extension, respectively, at the metacarpophalangeal (MCP) joints of the fingers in two static arm postures and under three conditions of electrical stimulation of the arm. The tasks were quantified in terms of maximum MCP torque [MCP flexion (MCPflex) or MCP extension (MCPext)] and activity of targeted (flexor digitorum superficialis or extensor digitorum communis) and nontargeted upper limb muscles. From a previous study on the MCP stretch reflex poststroke, we expected stroke subjects to exhibit a modulation of voluntary MCP torque production by arm posture and electrical stimulation and increased nontargeted muscle activity. Posture 1 (flexed elbow, neutral shoulder) led to greater MCPflex in stroke subjects than posture 2 (extended elbow, flexed shoulder). Electrical stimulation did not influence MCPflex or MCPext in either subject group. In stroke subjects, posture 1 led to greater nontargeted upper limb flexor activity during MCPflex and to greater elbow flexor and extensor activity during MCPext. Stroke subjects exhibited greater elbow flexor activity during MCPflex and greater elbow flexor and extensor activity during MCPext than control subjects. The results suggest that static arm posture can modulate voluntary distal motor activity and accompanying muscle activity in the paretic upper limb poststroke

Modulation of Stretch Reflexes of the Finger Flexors by Sensory Feedback from the Proximal Upper Limb Poststroke

Neural coupling of proximal and distal upper limb segments may have functional implications in the recovery of hemiparesis after stroke. The goal of the present study was to investigate whether the stretch reflex response magnitude of spastic finger flexor muscles poststroke is influenced by sensory input from the shoulder and the elbow and whether reflex coupling of muscles throughout the upper limb is altered in spastic stroke survivors. Through imposed extension of the metacarpophalangeal (MCP) joints, stretch of the relaxed finger flexors of the four fingers was imposed in 10 relaxed stroke subjects under different conditions of proximal sensory input, namely static arm posture (3 different shoulder/elbow postures) and electrical stimulation (surface stimulation of biceps brachii or triceps brachii, or none). Fast (300°/s) imposed stretch elicited stretch reflex flexion torque at the MCP joints and reflex electromyographic (EMG) activity in flexor digitorum superficialis. Both measures were greatest in an arm posture of 90° of elbow flexion and neutral shoulder position. Biceps stimulation resulted in greater MCP stretch reflex flexion torque. Fast imposed stretch also elicited reflex EMG activity in nonstretched heteronymous upper limb muscles, both proximal and distal. These results suggest that in the spastic hemiparetic upper limb poststroke, sensorimotor coupling of proximal and distal upper limb segments is involved in both the increased stretch reflex response of the finger flexors and an increased reflex coupling of heteronymous muscles. Both phenomena may be mediated through changes poststroke in the spinal reflex circuits and/or in the descending influence of supraspinal pathways

Our voice counts: adolescents’ view on their future in South Africa

We focus on the impact of societal change and related societal problems on the youth of post-apartheid South Africa. Within the parameters of an eco-systemic model, it is argued that adolescents’ perspectives on their future in this country could be negatively influenced by the extent of societal problems that are currently experienced in South Africa. Amidst severe problems such as poverty, unemployment, HIV/AIDS, and violent crime the findings of an empirical investigation into the views 1,326 adolescents from a variety of socio-economic backgrounds indicate that a general spirit of optimism and independence exists, paired with a strong desire to escape the trappings of poverty and to fulfil their career and social expectations. The findings indicate that a new, non-racial generation is emerging, but also highlight a formidable ethical dilemma: not societal factors, but ironically the ailing education system, is blocking the future ideals of thousands of South African adolescents.Keywords: adolescents; future expectations; societal problems; yout

Design considerations for a wearable monitor to measure finger posture

BACKGROUND: Objective measures of hand function as individuals participate in home and community activities are needed in order to better plan and evaluate rehabilitation treatments. Traditional measures collected in the clinical setting are often not reflective of actual functional performance. Recent advances in technology, however, enable the development of a lightweight, comfortable data collection monitor to measure hand kinematics. METHODS: This paper presents the design analysis of a wearable sensor glove with a specific focus on the sensors selected to measure bend. The most important requirement for the glove is easy donning and removal for individuals with significantly reduced range of motion in the hands and fingers. Additional requirements include comfort and durability, cost effectiveness, and measurement repeatability. These requirements eliminate existing measurement gloves from consideration. Glove construction is introduced, and the sensor selection and glove evaluation process are presented. RESULTS: Evaluation of commercial bend sensors shows that although most are not appropriate for repeatable measurements of finger flexion, one has been successfully identified. A case study for sensor glove repeatability using the final glove configuration and sensors does show a high degree of repeatability in both the gripped and flat hand positions (average coefficient of variability = 2.96% and 0.10%, respectively). CONCLUSION: Measuring functional outcomes in a portable manner can provide a wealth of information important to clinicians for the evaluation and treatment of movement disorders in the hand and fingers. This device is an important step in that direction as both a research and an evaluation method

The use of mixed methods as reflected in two eminent South African educational research journals

Published ArticleThe epistemological and ontological orientations relevant for this research are positivism, interpretivism and pragmatism. These paradigms of inquiry are associated with quantitatively oriented research traditions, qualitatively oriented research traditions and mixed methods research respectively. Researchers who use mixed methods build on the strengths of quantitative and qualitative methods and minimize their weaknesses. Since educational research is primarily evidence-based, the aim of the study was to explore the extent to which mixed methods research was reflected in two eminent South African educational research journals during the 11 year period, 2000 to 2010. To this end 1392 articles were analysed. Of the research articles published in the two journals, 17.8% and 15.1% respectively reported on the use of mixed methods. Quantitative methods dominated between 2000 and 2002, followed by a paradigm war in 2003 to 2007, and mainly qualitative methods from 2008 onwards. Mixed methods research was mostly used in the educational domains of didactics (inclusive of curriculum studies), management and social studies. The most dominant themes investigated in these fields were related to curricula and the NQF/OBE, transformation, staff diversity, e-learning and other teaching methods. The need to develop mixed methods research in all branches of social research in South Africa is indicated

High Mass Triple Systems: The Classical Cepheid Y Car

We have obtained an HST STIS ultraviolet high dispersion Echelle mode spectrum the binary companion of the double mode classical Cepheid Y Car. The velocity measured for the hot companion from this spectrum is very different from reasonable predictions for binary motion, implying that the companion is itself a short period binary. The measured velocity changed by 7 km/ s during the 4 days between two segments of the observation confirming this interpretation. We summarize "binary" Cepheids which are in fact members of triple system and find at least 44% are triples. The summary of information on Cepheids with orbits makes it likely that the fraction is under-estimated.Comment: accepted by A

The career orientation of final year teacher training students

The research was prompted by the assumption that the many problems in South African education (e.g. continuous curiculum changes, insufficient in-service training and support, classroom overcrowding, discipline problems,administrative paperwork, low teacher morale, high teacher attrition rate, low societal status of the teaching profession) must have an adverse effect on the career orientation of teacher training students. Our research was embedded in the theoretical framework of eco-systemic theory (Bronfenbrenner 1990), through which we indicated how the teacher is surrounded and influenced by various societal systems in four levels of proximity: the micro, meso, exo and macro levels. From these systems we established the conceptual framework, in which we discussed negative forces on the teacher as these are eminent in societal expectations about the teacher, the professional identity of the teacher and the retention rate in the teaching profession. The discussion of these negative forces and their impact affirmed our initial assumption and led to our research question: To what extent are teaching training students positively inclined towards a career in teaching? This question implied attention to a) the career motivation, and b) the moral values of the modern South African teaching training student. The empirical study was conceptualised as a pilot project. We involved the full number of final year teaching training students at one of the largest education faculties in South Africa, namely at the University of Pretoria. The students (n = 403) were asked to complete a questionnaire which focused inter alia on respondents’ exposure to daily news, reasons for choosing the education career path, attitudes towards the teaching profession and medium to long term prospects in the profession. Moral inclinations were also probed, e.g. with items on religion, discipline, language of instruction, multicultural teaching and being a role model. The questionnaire findings were verified in a focus group interview with five purposively selected respondents in the questionnaire survey. Our findings nullified our initial assumptions. Not only were the students strongly committed to their chosen career, notwithstanding the questionable societal status of the teaching profession and the formidable teaching challenges (of which they were apparently keenly aware), but they also conveyed a strong message about moral values and the teacher’s role in modelling those in and beyond the school. Our findings are prospective and certainly need verification on a broader scale. We are also planning a follow-up study with the same respondents, once they have completed two years of full time teaching. The findings could serve as impetus for education management measures to ensure that aspiring teachers’ level of commitment is sustainable. One of these measures could be an online advice and counselling service for beginner teachers.Die navorsing het ontstaan uit die aanname dat die onderwysproblematiek in Suid-Afrika (voortdurende kurrikulumwysigings, gebrekkige indiensopleiding, dissiplineprobleme, lae beroepsmotivering onder onderwysers en gebrekkige aansien van die onderwysberoep) ’n negatiewe uitwerking op die beroepsinstelling van onderwysstudente het. Vanuit die teoretiese raamwerk wat gebruik is, naamlik Bronfenbrenner (1990) se ekosistemiese samelewingsmodel, is die negatiewe kragte wat op die onderwys inwerk, nader toegelig. In die lig van die intensiteit van hierdie kragte het die volgende as navorsingsvraag gedien: In welke mate het die huidige onderwysstudent ’n positiewe beroepsingesteldheid? In ’n vraelysopname onder 403 finalejaar onderwysstudente, is die aanvanklike aanname verkeerd bewys. Die vraelysrespondente was nie alleen positief ingestel teenoor hul toekomstige loopbaan in die onderwys nie, maar hulle was ook uitgesproke oor hul taak daarin as morele rolmodelle. Die positiewe aard van ons voorlopige bevindings onderstreep alreeds die absolute noodsaaklikheid van onderwysbestuursmaatreëls om die volhoubaarheid van beginneronderwysers se positiewe beroepsingesteldheid te verseker. ’n Elektroniese advies- en motiveringsdiens vir beginneronderwysers kan heel moontlik as eerste en uitvoerbare projek hiertoe dien.http://www.journals.co.za/ej/ejour_akgees.htmlgv201

Polaris B, an optical companion of Polaris (alpha UMi) system: atmospheric parameters, chemical composition, distance and mass

We present an analysis of high-resolution spectroscopic observations of Polaris B, the optical companion of the Polaris Ab system. The star has a radial velocity V_r of -16.6km/s to -18.9km/s, and a projected rotational velocity vsini=110 km/s. The derived atmospheric parameters are: Teff=6900K; logg=4.3; V_t=2.5km/s. Polaris B has elemental abundances generally similar to those of the Cepheid Polaris A (Usenko et al. 2005a), although carbon, sodium and magnesium are close to the solar values. At a spectral type of F3V Polaris B has a luminosity of 3.868L_sun, an absolute magnitude of +3.30mag, and a distance of 109.5pc. The mass of the star is estimated to be 1.39M_sun, close to a mass of 1.38+/-0.61M_sun for the recently-resolved orbital periods companion Polaris Ab observed by Evans et al. (2007).Comment: 6 pages, 3 figures, 1 tabl

Causal mechanisms in the clinical course and treatment of back pain

In recent years, there has been increasing interest in studying causal mechanisms in the development and treatment of back pain. The aim of this article is to provide an overview of our current understanding of causal mechanisms in the field. In the first section, we introduce key concepts and terminology. In the second section, we provide a brief synopsis of systematic reviews of mechanism studies relevant to the clinical course and treatment of back pain. In the third section, we reflect on the findings of our review to explain how understanding causal mechanisms can inform clinical practice and the implementation of best practice. In the final sections, we introduce contemporary methodological advances, highlight the key assumptions of these methods, and discuss future directions to advance the quality of mechanism-related studies in the back pain field

Survivors of Chronic Stroke Experience Continued Impairment of Dexterity But Not Strength in the Nonparetic Upper Limb

Objective To investigate the performance of the less affected upper limb in people with stroke compared with normative values. To examine less affected upper limb function in those whose prestroke dominant limb became paretic and those whose prestroke nondominant limb became paretic. Design Cohort study of survivors of chronic stroke (7.2±6.7y post incident). Setting The study was performed at a freestanding academic rehabilitation hospital. Participants Survivors of chronic stroke (N=40) with severe hand impairment (Chedoke-McMaster Stroke Assessment rating of 2-3 on Stage of Hand) participated in the study. In 20 participants the prestroke dominant hand (DH) was tested (nondominant hand [NH] affected by stroke), and in 20 participants the prestroke NH was tested (DH affected by stroke). Interventions Not applicable. Main Outcome Measure Jebsen-Taylor Hand Function Test. Data from survivors of stroke were compared with normative age- and sex-matched data from neurologically intact individuals. Results When combined, DH and NH groups performed significantly worse on fine motor tasks with their nonparetic hand relative to normative data (PP\u3e.140). Conclusions Survivors of stroke with severe impairment of the paretic limb continue to present significant upper extremity impairment in their nominally nonparetic limb even years after stroke. This phenomenon was observed regardless of whether the DH or NH hand was primarily affected. Because this group of survivors of stroke is especially dependent on the nonparetic limb for performing functional tasks, our results suggest that the nonparetic upper limb should be targeted for rehabilitation