Best Predictor Of Performance Research Articles

Relationship Between Arm Usage and Instrumental Activities of Daily Living After Unilateral Stroke

Haaland KY, Mutha PK, Rinehart JK, Daniels M, Cushnyr B, Adair JC. Relationship between arm usage and instrumental activities of daily living after unilateral stroke. ObjectiveTo determine whether the preferred pattern of arm use after unilateral hemispheric damage was associated with better everyday functioning. Our previous work showed that right-handed stroke patients with right hemisphere damage (RHD) used their right, ipsilesional arm most frequently, while those with left hemisphere damage (LHD) used both arms together most frequently. This effect was explained by right-hand preference, but its relationship to functional performance is not known. DesignObservational cohort. SettingResearch laboratory. ParticipantsStroke patients (n=60; 30 RHD, 30 LHD) and healthy controls (n=52). InterventionsNot applicable. Main Outcome MeasuresThe Functional Impact Assessment was used to assess performance on instrumental activities of daily living (IADLs). ResultsThe preferred patterns of arm use were similar to those in our previous report. However, it was the greater use of both arms together that was associated with better IADL performance in both stroke groups. Ipsilesional arm use alone was not significantly associated with IADL performance in the RHD group and was associated with poorer performance in the LHD group. ConclusionsThe modal arm use pattern did not always optimize IADL functioning. Better IADL functioning in both stroke groups was associated with the use of both arms together, which is the most common arm use pattern of healthy individuals doing these same IADLs. An important practical question that arises from these findings is whether bilateral arm rehabilitation should be emphasized, because using both arms together is the best predictor of better performance on everyday tasks.

Paired-pulse afferent modulation of TMS responses reveals a selective decrease in short latency afferent inhibition with age

Changes in motor cortical excitability were examined in 2 groups of participants, young (18–30 years of age, n = 25) and senior (65–82 years of age, n = 31), using paired-pulse afferent stimulation with transcranial magnetic stimulation (TMS). Motor evoked potentials (MEPs) elicited by TMS at suprathreshold intensity (120% motor threshold) were first recorded in unconditioned trials (TMS alone) and then in conditioned trials, in which TMS pulses were preceded by median nerve stimulation at 3 different interstimulus intervals (ISI; 20, 50, and 200 ms). Conditioning of MEP responses revealed a similar pattern of modulation in the 2 age groups, with 2 periods of inhibition at 20- and 200-ms ISIs, separated by a period in which MEPs tended to return to baseline at a 50-ms ISI. Afferent-induced inhibition at the short interval (i.e., SAI 20-ms ISI), was selectively reduced in seniors, with half of them showing either low or no MEP suppression. Age-associated changes in SAI level were also good predictors of performance on tests of processing speed and dexterity. The selective decrease in SAI exhibited by many seniors is consistent with reported alterations in intracortical inhibition with age. Our observations also highlight the potential value of SAI, as a putative marker of central cholinergic activity, in predicting declines in motor and cognitive function with age.

Semantic Diversity Accounts for the “Missing” Word Frequency Effect in Stroke Aphasia: Insights Using a Novel Method to Quantify Contextual Variability in Meaning

Word frequency is a powerful predictor of language processing efficiency in healthy individuals and in computational models. Puzzlingly, frequency effects are often absent in stroke aphasia, challenging the assumption that word frequency influences the behavior of any computational system. To address this conundrum, we investigated divergent effects of frequency in two comprehension-impaired patient groups. Patients with semantic dementia have degraded conceptual knowledge as a consequence of anterior temporal lobe atrophy and show strong frequency effects. Patients with multimodal semantic impairments following stroke (semantic aphasia [SA]), in contrast, show little or no frequency effect. Their deficits arise from impaired control processes that bias activation toward task-relevant aspects of knowledge. We hypothesized that high-frequency words exert greater demands on cognitive control because they are more semantically diverse--they tend to appear in a broader range of linguistic contexts and have more variable meanings. Using latent semantic analysis, we developed a new measure of semantic diversity that reflected the variability of a word's meaning across different context. Frequency, but not diversity, was a significant predictor of comprehension in semantic dementia, whereas diversity was the best predictor of performance in SA. Most importantly, SA patients did show typical frequency effects but only when the influence of diversity was taken into account. These results are consistent with the view that higher-frequency words place higher demands on control processes, so that when control processes are damaged the intrinsic processing advantages associated with higher-frequency words are masked.

Perceptual Classification in a Rapidly Changing Environment

Humans and monkeys can learn to classify perceptual information in a statistically optimal fashion if the functional groupings remain stable over many hundreds of trials, but little is known about categorization when the environment changes rapidly. Here, we used a combination of computational modeling and functional neuroimaging to understand how humans classify visual stimuli drawn from categories whose mean and variance jumped unpredictably. Models based on optimal learning (Bayesian model) and a cognitive strategy (working memory model) both explained unique variance in choice, reaction time, and brain activity. However, the working memory model was the best predictor of performance in volatile environments, whereas statistically optimal performance emerged in periods of relative stability. Bayesian and working memory models predicted decision-related activity in distinct regions of the prefrontal cortex and midbrain. These findings suggest that perceptual category judgments, like value-guided choices, may be guided by multiple controllers.

A Relevant Distance Criterion for Interpolation of Head-Related Transfer Functions

In binaural synthesis, in order to realize more precise and accurate spatial sound, it would be desirable to measure a large number of the head-related transfer functions (HRTFs) in various directions. To reduce the size of the HRTFs, interpolation is often employed, where the HRTF for any direction can be obtained by a limited number of the representative HRTFs. In this paper, it is determined which distortion measure for interpolation of the HRTFs in the horizontal plane is most suitable for predicting audible differences in sound location. Four kinds of HRTF sets, measured using three human heads and one mannequin (KEMAR), were prepared for this study. Using various objective distortion criteria, the differences between interpolated and measured HRTFs were computed. These were then related to the results from the listening tests through receiver operator characteristic (ROC) curves. The results of the present study indicated that for the HRTF sets measured from three human heads, the best predictor of performance was obtained using the distortion measurement computed from the mel-cepstral coefficients, whereas the distortion measurement associated with interaural time delay predicted audible differences in sound location reasonably well for the KEMAR HRTF set. A feasibility test was conducted to verify the usefulness of the selected distortion measurement.

Predicting performance in contracting of basic health care to NGOs: experience from large-scale contracting in Uttar Pradesh, India

Escalating costs and increasing pressure to improve health services have driven a trend toward contracting with the private sector to provide traditionally state-run services. Such contracting is seen as an opportunity to combine theorized advantages of contracting with the efficiency of the private sector. There is still a limited understanding of the preconditions for successful use of contracting and the resources needed for their appropriate use and sustainability. This study assesses the large-scale contracting of 294 non-governmental organizations (NGOs) for delivery of basic health services in Uttar Pradesh, a state with almost 170 million in India. Due to high rates of discontinuation or non-renewal of contracts based on poor performance in the project, a better method for selecting partners was requested. Data on characteristics of the NGOs (intake data) and performance/outcome monitoring indicators were combined to identify correlations. The results showed that NGOs selected were generally small but well-established, had implemented at least two large projects, and had more non-health experience than health experience. Bivariate regressions of outcome score on each input variable showed that training experience, proposal quality and having 'health' contained in the objectives of the organization were statistically significant predictors of good performance. Factors relating to financial capacity, staff qualification, previous experience with health or non-health projects, and age of establishment were not. A combined training plus proposal score was highly predictive of outcome score (β = 1.37, P < 0.001). The combined score was found to be a much better predictor of outcome scores than a total score used to select NGOs (β = 0.073, P = 0.539). The study provides valuable information from large-scale contracting. Conclusions on criteria for selecting NGOs for providing basic health care could guide other governments choosing to contract for such services.

The assessment of adolescent female athletes using standing and reactive long jumps

The aim of this study was to evaluate the reliability of two long jump tasks and their ability to predict 10 m sprint performance in elite adolescent female athletes. Eight junior national-level female track and field athletes completed three standing (SLJ) and reactive long jumps (RLJ) on portable force plates, followed by three 10 m sprints. Intra-class correlation coefficients (ICC) and coefficients of variation (CV) were calculated to examine reliability. Linear regression results identified the best predictor of average and best 10 m sprint time from the jump kinematic and kinetic measures. The ICCs and CVs indicated good reliability for the majority of kinetic measures however, better reliability was reported for the SLJ. The SLJ was a good predictor of best and average 10 m sprint time, with average horizontal power the best predictor of performance (best; R 2 = 0.751, p = 0.003, Standard Error of Estimate (SEE)% = 2.2 average; R 2 = 0.708, p = 0.005, SEE% = 2.5).

Analysis of Skeletal Muscle Metrics as Predictors of Functional Task Performance

PURPOSE: The ability to predict task performance using physiological performance metrics is vital to ensure that astronauts can execute their jobs safely and effectively. This investigation used a weighted suit to evaluate task performance at various ratios of strength, power, and endurance to weight. METHODS: Twenty subjects completed muscle performance tests and functional tasks representative of those that would be required of astronauts during planetary exploration (see table for specific tests/tasks). Subjects performed functional tasks while wearing a weighted suit with additional loads ranging from 0-120% of initial weight. Performance metrics were time to completion for all tasks except hatch opening, which consisted of total work. Task performance metrics were plotted against muscle metrics normalized to body (subject weight + external load; BW) for each trial. Fractional polynomial regression was used to model the relationship between muscle and task performance. CONCLUSION: LPMIF/BW is the best predictor of performance for predominantly lower-body tasks that are ambulatory and of short duration. LPMIF/BW is a very practical predictor of occupational task performance as it is quick and relatively safe to perform. Accordingly, bench press work best predicts hatch-opening work performance.

Understanding verbal fluency in healthy aging, Alzheimer's disease, and Parkinson's disease.

Verbal fluency measures are frequently part of batteries designed to assess executive function (EF), but are also used to assess semantic processing ability or word knowledge. The goal of the present study was to identify the cognitive components underlying fluency performance. Healthy young and older adults, adults with Parkinson's disease, and adults with Alzheimer's disease performed letter, category, and action fluency tests. Performance was assessed in terms of number of items generated, clustering, and the time course of output. A series of neuropsychological assessments were also administered to index verbal ability, working memory, EF, and processing speed as correlates of fluency performance. Findings indicated that regardless of the particular performance measure, young adults performed the best and adults with Alzheimer's disease performed most poorly, with healthy older adults and adults with Parkinson's disease performing at intermediate levels. The exception was the action fluency task, where adults with Parkinson's disease performed most poorly. The time course of fluency performance was characterized in terms of slope and intercept parameters and related to neuropsychological constructs. Speed of processing was found to be the best predictor of performance, rather than the efficiency of EF or semantic knowledge. Together, these findings demonstrate that the pattern of fluency performance looks generally the same regardless of how performance is measured. In addition, the primary role of processing speed in performance suggests that the use of fluency tasks as measures of EF or verbal ability warrants reexamination.

Circulating angiotensin converting enzyme in endurance horses: effect of exercise on blood levels and its value in predicting performance

Investigate angiotensin converting enzyme (ACE) activity in equine plasma as a predictor of performance in endurance competitions and the effect of endurance exercise on ACE activity. Precompetition values of ACE activity in equine blood are correlated with performance results and with heart rates pre- and post competition used as indicators of fitness. Endurance exercise increases ACE activity. Nineteen horses participating in an 80 km endurance competition had venous blood samples collected before and after the ride. ACE activity and total protein were measured in the blood samples and heart rates and finishing positions were recorded. Statistical analysis included paired t tests and Spearman's rank correlation coefficient. Of the 19 horses enlisted, only 16 horses completed the ride. Of these 16, another 2 were disqualified at the last veterinary check. When the 16 horses were considered, precompetition heart rate, but not ACE, was correlated with finishing position. When only the 14 horses that were classified were considered, the association disappeared. ACE activity was similar before and after competition. Precompetition ACE activity in endurance horses competing in an 80 km event was not associated with either finishing position or heart rates before or after competition, indicating that the enzyme is not a good predictor of performance in this form of equestrian competition. Endurance competition did not significantly alter ACE activity in this group of horses.

Predictors of Performance on the MMSE and the DRS-2 Among American Indian Elders

Little is known about factors that predict older American Indians' performance on cognitive tests. This study examined 137 American Indian elders' performance on the MMSE and the Dementia Rating Scale-Second Edition (DRS-2). Multivariate regression identified younger age, more education, not receiving Supplemental Security Income, and frequent receipt of needed health care as predictors of better performance on the MMSE. Better performance on the DRS-2 was predicted by more education, boarding school attendance, not receiving Supplemental Security Income, and frequent receipt of needed health care. This study points to the importance of economic and educational factors on cognitive test performance among American Indian elders.

Predictors of Performance on the MMSE and the DRS-2 Among American Indian Elders

Little is known about factors that predict older American Indians' performance on cognitive tests. This study examined 137 American Indian elders' performance on the MMSE and the Dementia Rating Scale-Second Edition (DRS-2). Multivariate regression identified younger age, more education, not receiving Supplemental Security Income, and frequent receipt of needed health care as predictors of better performance on the MMSE. Better performance on the DRS-2 was predicted by more education, boarding school attendance, not receiving Supplemental Security Income, and frequent receipt of needed health care. This study points to the importance of economic and educational factors on cognitive test performance among American Indian elders.

Organizational Climate (OC) as Employees’ Satisfier: Empirical Evidence from Pharmaceutical Sector

The satisfaction of employees with organizational climate is predictor of better performance. Organizationalclimate is having direct bearing on employees’ satisfaction. The satisfaction of employees with organizationalclimate enhances positive organizational outcomes: efficiency, productivity, organizational commitment andcohesiveness of coworkers while it reduces negative outcomes: turnover, deviant behavior at work, absenteeismand stealing of company property. This study is conducted to measure the satisfaction of middle managers withorganizational climate in pharmaceutical sector of Pakistan. A questionnaire survey was conducted to collect theresponse. 66 organizations were selected through cluster sampling technique, from four major cities of Pakistan,out of the total 66 companies (51 local and 15 multinational organizations). Out of these organizations 246middle level managers were surveyed (170 from local companies and 70 from multinationals). The majority ofthem were male, having university degrees, with age less than or equal to 35 years. The results reveal that inmajority of the managers were satisfied with organizational climate in both local and multinational organizations.Respondents from multinational organizations were found to be more satisfied then the respondents from localcompanies. Detailed results are discussed in findings section.

The impact of organizational justice on work performance

PurposeThe purpose of this paper is to develop and test a model that identifies the impact of organizational justice on work performance. The model examined the mediating role played by organizational commitment and leader‐member exchange (LMX) in linking organizational justice and work performance.Design/methodology/approachThe data were collected from 793 completed questionnaires sampling employees from industries across the People's Republic of China. The questionnaire included scales to measure organizational justice, organizational commitment, LMX, and work performance. The measurement of constructs and the hypothesized relationships among variables were assessed by the use of structural equation modeling. The Baron and Kenny approach was used to test the mediating effects.FindingsFirst, the relationship of organizational justice to work performance was mostly indirect, mediated by organizational commitment and LMX. Second, among the three kinds of organizational justice, interactional justice was the best predictor of performance. Lastly, organizational commitment accounted for more of the variance than LMX did in the mediating mechanism.Research limitations/implicationsThe model developed in this article provides important insights in the study of the relationship between organizational justice and work performance. Future research needs to examine the model using a cross‐national sample.Originality/valueThe link between organizational justice and work performance was mostly mediated by organizational commitment and LMX.

Endocrine and psychological stress responses in a simulated emergency situation

Several studies have assessed the effects of training using patient simulation systems on medical skills. However, endocrine and psychological stress responses in a patient simulation situation and the relationship between stress reactivity and medical performance have been studied rarely, so far. Medical students (18 males and 16 females) who had completed at least two months anaesthesiology training participated in the study. In a counterbalanced cross-over design they were subjected to three conditions: rest, laboratory stress (LS; public speaking), and simulated emergency situation (SIM; myocardial ischemia and ventricular fibrillation). Salivary cortisol and psychological responses (visual analogue scales, VAS) were assessed every 15 min from 15 min prior to until 60 min after intervention. Differences between stress and rest conditions were analysed. Medical performance was assessed according to the European Resuscitation Council's Guidelines for Resuscitation. As compared to rest, cortisol increased significantly in both stress conditions with different time courses in LS and SIM. Psychological responses in SIM exceeded those in LS. Cortisol increase in LS (r(s)=.486; p=.019) but not in SIM (r(s)=.106; p=.631) correlated significantly with medical performance. A simulated emergency situation is a profound stressor. The positive relationship between endocrine stress responsiveness in a standard laboratory situation and medical performance in a simulated emergency situation indicates that high stress responsiveness might be a predictor of good performance. At the same time the high stress response might counteract educational efforts associated with training using high-fidelity patient simulation.

Integration of supply chain IT and lean practices for mass customization

PurposeThe purpose of this paper is to examine the use of specific supply chain information technologies (IT) for e‐commerce, e‐procurement, and enterprise resource planning (ERP), when implementing lean practices to achieve mass customization (MC) performance. The study further investigates how these technologies may be deployed differently in product and service focused contexts. “Best practices” of high performing MC firms are also explored.Design/methodology/approachSurvey method was employed to collect data from 711 firms in 23 countries. Exploratory factor analysis was employed to establish simple factor structure and construct validity. Hierarchical multiple regression was used to analyze relationships between lean practices, IT use, and MC performance in aggregated and bifurcated samples of product and service focused manufacturers. T‐tests were used to examine differences between the practices employed by high and low MC performers.FindingsFindings suggest that lean practices can reasonably predict MC performance. In this context, of lean practices, e‐commerce and e‐procurement reasonably predict MC performance. ERP is not shown to predict MC performance. Results suggest that e‐commerce use is a better predictor of performance than e‐procurement or ERP for service focused manufacturers. E‐commerce and e‐procurement appear to be reasonable predictors of MC performance in product manufacturers, while ERP is not. “Best practices” related to lean practices, e‐commerce, e‐procurement, and ERP emerge among high MC performers.Originality/valueThis paper describes what is believed to be the first study to examine these three IT approaches in the context of lean practices and supply chain MC performance. This paper also contributes to the growing interest in differences among product and service focused manufacturing firms. Finally, specific “best practices” are provided to add value for practitioners.

Upper Limb Function as an Outcome Predictor in Acute Stroke

To the Editor: The article by the Early Prediction of functional Outcome after Stroke study (EPOS)1 investigators demonstrated how the active finger extension scale may be a strong predictor of recovery in patients with stroke. This finding has for a long time been considered a relevant item in daily clinical practice with the purpose of planning tailored rehabilitation programs.2,3 A diffused and useful tool for the assessment of distal limb motor function is the Canadian Neurological Scale.4,5 This scale is well known and validated among both neurological and physiatric settings with good interrater reliability.6,7 A multicentric study was …

Oxygen Kinetics In A 200-m Front Crawl Maximal Swimming Effort

Oxygen uptake (VO2) assessment is of particular interest in training and performance diagnosis, as well as in swimming bioenergetics. However, studies of VO2 kinetics conducted in real swimming pool conditions are scarce mostly due to environmental and instrumental restrictions. PURPOSE: To describe the VO2 kinetics during a maximal 200m crawl effort, and to establish whether VO2peak is a good predictor of performance. METHODS: Seven crawl elite male swimmers (20.0±1.9 yrs, 76.4±6.0 kg and 185.6±6.2 cm) performed an all-out 200m crawl swim in a 25m pool. VO2 was measured using a telemetric portable gas analyzer connected to the swimmer by a low resistance respiratory snorkel and valve system. Gas exchange parameters were measured breath-by-breath and values averaged every 5 s. VO2 kinetics parameters were determined by nonlinear monoexponential fitting (the cardiodynamic phase was not considered). RESULTS: On-VO2 kinetics started by a sudden and exponential increase in VO2 at the onset of the effort. The mean value of the amplitude of VO2 fast component was 39.7±6.5 mL.kg-1.min-1. No on-VO2 slow component was observed. Figure 1 shows a sample VO2 curve, being observed that the swimmers were not able to maintain the higher values of VO2 till the end of the 200m effort. Off-VO2 kinetics showed the typical two-phase decrease in VO2. Mean VO2peak (70.3±5.6 mL·kg-1·min-1) was related with mean 200m velocity (1.43±0.03 m.s-1, r=0.90, p<0.01).Fig 1: On and off-VO2 kinetics of one swimmer during and after a 200-m maximal swim, being identified the amplitude, time delay and time constant of the fast component.CONCLUSION: Besides characterizing the VO2 on-kinetics of a 200m maximal swim, these results suggest that VO2peak is a good predictor of 200m crawl swimming performance, confirming the relevance of the aerobic contribution to energy demands in middle distance events. Supported by PTDC/DES/101224/2008.

Dose-Response Relationship Between Interval Training Frequency And Lactate Threshold

Endurance performance is determined by numerous factors, including maximal oxygen uptake (VO2max), economy, and lactate threshold (LT). Many researchers agree that LT is among the best predictors of performance in endurance-related events (Midgley et al., 2007), yet the attributes of a training program aimed at positively modifying LT are not well understood. PURPOSE: The purpose of this study was to determine if interval training at 110-120% above peak power output one and two days per week would elicit improvements in LT. METHODS: Participants (N=34) were randomized to either a control group or 6 wk interval training group (1 day/wk or 2 days/wk). Interval training on a cycle ergometer was performed at 110-120% peak workload. Participants were instructed to not change their usual physical activity habits or diet throughout the study. Primary outcome measures (VO2max, LT at %VO2max, peak workload) were analyzed using a two-factor mixed ANOVA, with the between factor "experimental group" and repeated factor "trial" (baseline, 6 wk).TABLE: Physiological characteristics at baseline and 6 wk for control and interval training groups (mean ± SD).RESULTS: Physiological characteristics at baseline and 6 wk for participants in each experimental group are presented in the Table. After 6 wk, LT (%VO2max) increased significantly (p < 0.05) in both 1 day/wk (3.8 ± 3.1%) and 2 days/wk (7.7 ± 2.7%) groups. There was a significant interaction between exercise frequency and LT (%VO2max) values (p < 0.05) indicating that LT responded differently to 1 day/wk and 2 days/wk of interval training. CONCLUSION: Our findings demonstrate that high-intensity, interval training may be a successful strategy for modifying LT. Moreover, our results suggest that there is a dose-response relationship between frequency of interval training and the magnitude of LT improvement.

Motivating Firm-Sponsored E-Collective Work

This article sheds light on the factors that motivate online communities to collectively enact work in firm-sponsored initiatives. We term the general approach to online distributed knowledge-based work: “e-collective work”. While the literature has focused in understanding motivation in self-organized e-collective work (e.g. Wikipedia, Linux), our understanding is limited regarding firm-sponsored e-collective work. The study presented here builds on several case studies with a particular focus on Amazon’s Mechanical Turk (AMT), a firm-sponsored e-collective work endeavor where contributors are paid for participating. In particular, we analyze the motivational factors – from volunteerism to non-volunteerism – that lead to greater participation and contribution performance on the part of this online community. The results of the statistical analysis of 391 complete responses to an online survey of contributors to the AMT show that volunteerism factors are not good predictors of performance. Instead, non-volunteerism factors are found to be reliable determinants of performance in this firm-sponsored online community. In particular: (1) money – an unusual motivation factor in online communities, – and (2) fun – a typical motivation found in open source communities – are found to be strong predictors across different measures of performance. In addition, (3) free time – an intuitively reasonable explanation for participation – is found to have a negative effect on the duration of participation. It is apparent from these findings that contributors in this firm-sponsored e-collective initiative are in for monetary profit and fun, while they do not consider their time spent solving problems as free time. These findings contribute to the strategy literature, enhancing our understanding of this new source of competitive advantage for the firm, lying outside the boundaries of the formal interorganizational fabric and bridging into the public domain. The implications for practice are important as online collective approaches to work offer firms a radical and seemingly effective alternative to organizing knowledge-based work.