Changes in the receptive fields of cat retinal ganglion cells affected by pressure on the optic nerve

In the cat optic nerve a lesion was induced by brief application of pressure. It selectively blocked impulse conduction in large diameter fibres of the retinal ganglion cells. Electrophysiological examination of single optic axons several weeks later demonstrated a gross alteration of the visual properties of the affected BT/Y ganglion cells. It is suggested that the alteration of receptive field properties may reflect the cellular and dendritic response to distant focal injury of the axon.     

Predicting which patient will fall again… and again

In order to compare the characteristics, preventive interventions and outcomes of single and multiple fallers, a retrospective cross-sectional study was conducted in a 680-bed acute-care hospital in Western Australia Fifty patients falling more than once (multiple fallers) were randomly selected from all patients reported to have fallen between 1 July 1989 and 31 December 1989, and age–sex matched with 50 patients falling once in the trial period (single fallers) In total, 382 in-patients were reported to have sustained 578 falls in the 6-month trial period Fifty-two per cent of these falls involved multiple fallers An analysis of the 100 single and multiple fallers showed that single fallers were more likely to have fallen from their bed, be discharged home from hospital, and be clinically deteriorating at the time of the fall Multiple fallers were more likely to be transferred to a long-term nursing facility after discharge from hospital, suffer blindness/poor vision, be sedated post fall, be ordered to be restrained following a fall, and be hospitalized for longer periods There was also a tendency for multiple fallers to repeat the type and location of the fall on successive falls Stepwise logistic regression showed that falling from the bed on the first fall predicted remaining a single faller Being ordered to be restrained following the first fall and hospitalized for longer periods predicted the patient would fall repeatedly Further analytical research incorporating an expanded number of independent variables is needed to allow confident assertions of causality To test the effectiveness of preventive measures, a prospective longitudinal study is required.     

The test–retest reliability of the onset of concentric and eccentric vastus medialis obliquus and vastus lateralis electromyographic activity in a stair stepping task

Study design: Test–retest reliability using a repeated measures design. Objectives: The aim of this study was to evaluate the test–retest reliability of measurement of onsets of electromyographic (EMG) activity of vastus medialis oblique (VMO) and vastus lateralis (VL) during a stair stepping task. Background: Differences in the timing of onset of VMO and VL have been hypothesized to contribute to patellofemoral pain syndrome. However, no studies have investigated the reliability of the EMG onset of VL and VMO using a direct measure of EMG onset timing. Methods and measures: Ten asymptomatic subjects were assessed by the same examiner on two occasions one week apart. The relative difference in the timing of onset of EMG activity of VMO and VL was quantified by subtracting VMO EMG onset from that of VL. Results: The difference in EMG onsets during the concentric task (step up) had an intraclass correlation coefficient (ICC) of 0·91 with a standard error of measurement of 6·20 ms (95% CL 12·20 ms). The difference in EMG onsets during the eccentric task (step down) had an ICC of 0·96 with a standard error of measurement of 5·90 ms (95% CL 11·56 ms). Conclusions: The results indicate that in a normal population a difference of greater than 12·20 ms in the concentric and 11·56 ms in the eccentric phase of stair stepping would be required to demonstrate a significant difference in EMG onsets of VMO and VL between groups. Further research is required to determine the degree of measurement error in a population with specific pathologies.     

Consumer Involvement in the South Australian State Policy for Planned Home Birth

Abstract: Two consumer representatives were participants in the development of their state government’s Policy for Planned Birth At Home in South Australia. It was released in November 2007 to guide staff in public hospital and community midwifery programs, and the first hospital‐based home birth service is commencing in February 2009. Consumer experiences of policy development and perceived benefits of consumer involvement for policy and transparency processes are described. Inclusion of consumers widely and actively during development and reform of maternity care is essential if real consumer participation is to occur and contribute to care that is truly woman‐centered. (BIRTH 36:1 March 2009)