Inverse Modeling for MEG/EEG data

We provide an overview of the state-of-the-art for mathematical methods that are used to reconstruct brain activity from neurophysiological data. After a brief introduction on the mathematics of the forward problem, we discuss standard and recently proposed regularization methods, as well as Monte Carlo techniques for Bayesian inference. We classify the inverse methods based on the underlying source model, and discuss advantages and disadvantages. Finally we describe an application to the pre-surgical evaluation of epileptic patients.Comment: 15 pages, 1 figur

The effect of dynamic ankle-foot orthoses on the balance and gait of stroke patients

The present research aimed to assess the effects of a novel type of orthosis, the Dynamic Ankle Foot Orthosis (DAFO), on the balance and gait characteristics of hemiparetic subjects. The DAFO is a low splint with a custom-moulded insole, which is believed to support foot alignment, ankle supination-pronation and provide minimal restriction of the ankle joint flexion-extension. It was hypothesised that DAFOs improve motor behaviour after stroke involving the acquisition of standing balance (hypothesis I) and gait (hypothesis II) compared with using shoes. It was proposed that users' subjective opinions of DAFOs would support the findings of the device's ability to modify human performance such that they are beneficial when used as a part of rehabilitation management for stroke patients (hypothesis III). Twenty-two stroke subjects were randomly allocated to experimental (with DAFO and shoes-only) and control (using shoes-only) groups. Subjects followed twelve weeks of experimental trials comprising three data collections. The testing procedure was developed from preliminary work, which involved a pilot study and reliability tests. Standing balance was measured using forceplatform apparatus. The parameters investigated were: the velocity and sway index of the CoP, and F(mean), F(sd) and F(slope) of shear forces. Kinematic gait performance was assessed using a 3-D four-camera motion measurement system. The parameters studied were: the gait velocity, stride length, step length, cadence, and single stance phase, together with the minimum/maximum values of the angular displacement and velocity of the foot, shank, and thigh segments in the saggittal plane during two strides. An open questionnaire was used to evaluate subjects' opinions regarding the use of DAFOs. Overall, the quantitative studies did not identify consistent and statistically significant differences between the two experimental situations for these groups of patients. In the studies of balance, none of the parameter comparisons analysed within- and between- groups achieved statistical significance. In the studies of gait, statistically significant differences were identified for some (but not all) parameters. It is unknown whether any single or combination of balance and gait variables can be used to describe human gait entirely. On this basis, hypotheses I and II were rejected. However, these are tentative conclusions. Thus, difficulties in maintaining the stroke subject cohort number for these studies meant that the analyses probably lacked sufficient statistical power to detect small but potentially important differences in DAFO mediated actions. Furthermore, in several cases, clear differences in the magnitude of balance and gait parameters between DAFO and shoe users were apparent, and these differences were often consistent with nearer normal levels associated with use of the device (suggesting potentially beneficial influences). Thus, positive effects of the DAFO on lateral velocity of sway and variability of the spectral frequency were evident for some subjects. The gait velocity, stride length and single stance phase were also nearer normal values using DAFOs than without them. In addition, the maximum foot velocity value was improved in the middle of swing phase on the affected side, which may indicate improvement to the ankle dorsiflexion function using these devices. In contrast to the inconclusive balance and gait findings, the outcome of the questionnaire assessments was clear. The majority of subjects provided very positive feedback with regard to DAFO use. Most subjects expressed confidence in the splint, which they perceived as helpful for their walking ability in day life. Some difficulties were noticed with donning and doffing the DAFO, but the perceived benefits outweighed this consideration. These qualitative studies therefore provide the most convincing evidence to support the idea that DAFOs improve stroke patients' balance and gait, and that this type of orthosis may form a useful adjunct to rehabilitation strategies. However, as the proposals set out for this research were related, acceptance of hypothesis III requires that at least one of the preceding hypotheses be accepted. On this basis, hypothesis III was also rejected. In conclusion, although this work failed overall to demonstrate a significant effect of DAFOs on the rehabilitation of stroke patients, the anecdotal evidence obtained adds to knowledge in this field. The research identified some parameters of balance and gait, which might be influenced by the device in a beneficial manner. These parameters may be more useful to use in future investigations. The reasons for the discrepant outcomes of the quantitative and qualitative studies are unclear. However, it is suggested that there may be uncontrolled variables within either the patient group or in the DAFOs (or both) which mean that some DAFOs work better than others. It is proposed that further studies of the DAFO are warranted.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Sustaining modified behaviours learnt in a diabetes prevention program in regional Australia : the role of social context

BackgroundThe Greater Green Triangle diabetes prevention program was conducted in primary health care setting of Victoria and South Australia in 2004--2006. This program demonstrated significant reductions in diabetes risk factors which were largely sustained at 18 month follow-up. The theoretical model utilised in this program achieved its outcomes through improvements in coping self-efficacy and planning. Previous evaluations have concentrated on the behavioural components of the intervention. Other variables external to the main research design may have contributed to the success factors but have yet to be identified. The objective of this evaluation was to identify the extent to which participants in a diabetes prevention program sustained lifestyle changes several years after completing the program and to identify contextual factors that contributed to sustaining changes.MethodsA qualitative evaluation was conducted. Five focus groups were held with people who had completed a diabetes prevention program, several years later to assess the degree to which they had sustained program strategies and to identify contributing factors.ResultsParticipants value the recruitment strategy. Involvement in their own risk assessment was a strong motivator. Learning new skills gave participants a sense of empowerment. Receiving regular pathology reports was a means of self-assessment and a motivator to continue. Strong family and community support contributed to personal motivation and sustained practice.ConclusionsFamily and local community supports constitute the contextual variables reported to contribute to sustained motivation after the program was completed. Behaviour modification programs can incorporate strategies to ensure these factors are recognised and if necessary, strengthened at the local level.<br /

Motivation and characterization of Finnish meat inspection veterinarians

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Factors associated with self-assessed increase in tobacco consumption among over-indebted individuals in Germany: a cross-sectional study

Background Over-indebtedness is an increasing phenomenon in industrialised nations causing individual hardship and societal problems. Nonetheless, few studies have explored smoking among over-indebted individuals. Methods A cross-sectional survey (n=949) on retrospectively assessed changes in tobacco consumption was carried out in 2006 and 2007 among clients of 84 officially approved debt and insolvency counselling centres in Germany (response rate 39.7%). Logistic regressions were performed to explore factors associated with reports of increased smoking after onset of over-indebtedness. Results 63% of all respondents stated daily or occasional tobacco consumption. Almost one fifth reported an increase in smoking after becoming over-indebted. Females were less likely to report increased smoking than men (aOR 0.66, 95% CI 0.44-0.99) whereas respondents who had been over-indebted for more than 10 years were more likely to report increased smoking than those who had been over-indebted for less than five years (aOR 1.66; 95%-CI 1.00-2.76). The odds of increased smoking were also elevated among those who reported that their families and friends had withdrawn from them as a consequence of their over-indebtedness (aOR 1.82; 95%-CI 1.06-3.14). Conclusions The study identifies over-indebted individuals and particularly over-indebted men as a high-risk group of smokers. Low levels of social embeddedness/support were associated with a further increase in smoking after becoming over-indebted. Given recent increases of over-indebtedness, the findings highlight the need to develop appropriate public health policies

Scheduled Emergency Trauma Operation : The Green Line Orthopedic Trauma Surgery Process Of Care

Background and Aims: Traditionally, patients requiring an orthopedic emergency operation were admitted to an inpatient ward to await surgery. This often led to congestion of wards and operation rooms while, for less urgent traumas, the time spent waiting for the operation often became unacceptably long. The purpose of this study was to evaluate the flow of patients coded green in a traffic light-based coding process aimed at decreasing the burden on wards and enabling a scheduled emergency operation in Central Finland Hospital. Materials and Methods: Operation urgency was divided into three categories: green (>48 h), yellow (8-48 h), and red (Peer reviewe