Effects of mental fatigue on 8-13Hz brain activity in people with spinal cord injury

Brain computer interfaces (BCIs) can be implemented into assistive technologies to provide 'hands-free' control for the severely disabled. BCIs utilise voluntary changes in one's brain activity as a control mechanism to control devices in the person's immediate environment. Performance of BCIs could be adversely affected by negative physiological conditions such as fatigue and altered electrophysiology commonly seen in spinal cord injury (SCI). This study examined the effects of mental fatigue from an increase in cognitive demand on the brain activity of those with SCI. Results show a trend of increased alpha (8-13Hz) activity in able-bodied controls after completing a set of cognitive tasks. Conversely, the SCI group showed a decrease in alpha activity due to mental fatigue. Results suggest that the brain activity of SCI persons are altered in its mechanism to adjust to mental fatigue. These altered brain conditions need to be addressed when using BCIs in clinical populations such as SCI. The findings have implications for the improvement of BCI technology.

Proteinuria as a predictor of renal functional outcome after revascularization in atherosclerotic renovascular disease (ARVD)

BACKGROUND

Renal revascularization is performed in 16% of newly diagnosed patients with atherosclerotic renovascular disease (ARVD). Although there may be some improvement in hypertension control as a result of intervention, renal functional outcomes are known to vary. Pre-existing renal parenchymal injury, as manifested by proteinuria, is associated with poor functional outcome in conservatively managed ARVD patients, but this association has not been investigated in patients undergoing revascularization.

METHODS

Retrospective case note review of 83 ARVD patients who underwent renal revascularization in four centres within a renal network between 1998 and 2003 was undertaken. Amongst other parameters, baseline proteinuria was correlated with renal functional outcome post revascularization. Renal functional outcome was determined over a mean follow up of 22 months by rate of change of estimated glomerular filtration rate (eGFR) over time.

RESULTS

Univariate analysis showed that proteinuria >0.6 g/day was the only significant predictor of poor outcome after revascularization. The relationship persisted with multivariate analysis, and linear regression showed a correlation between baseline proteinuria and decline in eGFR with time (r(2) = 0.058, P = 0.039).

CONCLUSION

This study confirms that prior renal parenchymal injury, here reflected by proteinuria at baseline, is a major arbiter of renal functional outcome after renal revascularization in ARVD.

The relationship between prostate cancer knowledge and beliefs and intentions to attend PSA screening among at-risk men

OBJECTIVE

To examine the level of knowledge regarding prostate cancer and screening, to investigate prostate cancer illness perceptions, and to test the efficacy of the theory of planned behaviour (TPB) for understanding intentions to attend prostate-specific antigen (PSA) screening, when offered by a doctor or self-initiated.

METHODS

Two hundred and twenty three men completed the PROCASE knowledge scale, the Revised Illness Perceptions Questionnaire and a questionnaire developed to assess attitudes, subjective norms and perceived control over intentions to attend for PSA testing.

RESULTS

Participants had a high level of knowledge and accurate perceptions of prostate cancer. Controlling for knowledge and experience with prostate cancer, the TPB accounted for 49% (p<0.001) of the variation in intentions to attend if recommended by a doctor.

CONCLUSION

The sample of at-risk men were characterised by good knowledge, accurate mental representation of prostate cancer, and positive beliefs towards the PSA test. Components of the TPB accounted for statistically significant amounts of variation in intentions to attend for testing.

PRACTICE IMPLICATIONS

Beliefs about prostate cancer do not appear to influence PSA testing intentions; healthcare providers' recommendations may have the strongest influence on decisions to attend for PSA testing.

Increase in regularity and decrease in variability seen in electroencephalography (EEG) signals from alert to fatigue during a driving simulated task

Driver fatigue is a prevalent problem and a major risk for road safety accounting for approximately 20-40% of all motor vehicle accidents. One strategy to prevent fatigue related accidents is through the use of countermeasure devices. Research on countermeasure devices has focused on methods that detect physiological changes from fatigue, with the fast temporal resolution from brain signals, using the electroencephalogram (EEG) held as a promising technique. This paper presents the results of nonlinear analysis using sample entropy and second-order difference plots quantified by central tendency measure (CTM) on alert and fatigue EEG signals from a driving simulated task. Results show that both sample entropy and second-order difference plots significantly increases the regularity and decreases the variability of EEG signals from an alert to a fatigue state.

A national survey of telemedicine in the Republic of Ireland

We conducted a national survey of hospitals in the Republic of Ireland to assess their use of telemedicine. Information was sought from 187 hospitals and replies were received from 157, a response rate of 84%. Activity was identified in a total of 40 hospitals (25% of the respondents). The main disciplines using telemedicine were radiology, pathology, neurosurgery, oncology and paediatrics, and the main applications were teleradiology (25 hospitals), videoconferencing (16) and telepathology (5). Dublin, the capital city, was found to act as a centre for telemedicine activity for the whole country. A number of regional networks had developed in the east, but the pattern of development in the west was very different where there were mainly isolated links. One fully operational national network was found but this was only used for consultation in one discipline (neurosurgery). It appears that the development of telemedicine in the Republic of Ireland has been unplanned. A national telemedicine strategy might lead to an integrated national network in the future, which could help to provide more equitable access to health care.

An economic evaluation of oxaliplatin for the adjuvant treatment of colon cancer in the United Kingdom (UK)

The MOSAIC study was the first trial to show a statistically significant disease-free survival benefit for a treatment regimen for stage III colon cancer in the adjuvant setting. At 4 years, there was a 25% reduction in the risk of disease recurrence in these patients for the combination of oxaliplatin/5-FU/FA compared with 5-FU/FA alone (p=0.002). This analysis evaluates the long-term cost effectiveness of oxaliplatin given in combination with 5-FU/FA from the perspective of the NHS in the United Kingdom (UK). The cost per quality-adjusted life-year gained over a lifetime was calculated using patient level data from the MOSAIC trial. Trial data were available for a median of 4 years of follow-up, these data were then extrapolated to a lifetime horizon. The estimated incremental lifetime cost per quality-adjusted life-year of oxaliplatin/5-FU/FA compared with 5-FU/FA alone in patients with stage III postoperative colon cancer is pound 4805. This compares favourably with other accepted interventions in oncology.

Electroencephalographic slowing and reduced reactivity in neuropathic pain following spinal cord injury

STUDY DESIGN

Brain wave activity in people with paraplegia, with and without neuropathic pain, was compared to brain wave activity in matched able-bodied controls.

OBJECTIVES

To investigate whether spinal cord injury with neuropathic pain is associated with a slowing of brain wave activity.

SETTING

Australia.

METHODS

Electroencephalographic (EEG) data were collected in the eyes open (EO) and eyes closed (EC) states from 16 participants with paraplegia (eight with neuropathic pain and eight without pain) and matched able-bodied controls. Common EEG artefacts were removed using independent component analysis (ICA). Peak frequency in the theta-alpha band and EEG power in the delta, theta, alpha and beta frequency bands were compared between groups.

RESULTS

The results show significant slowing of the EEG in people with neuropathic pain, consistent with the presence of thalamocortical dysrhythmia (TCD). Furthermore, people with neuropathic spinal cord injury (SCI) pain had significantly reduced EEG spectral reactivity in response to increased or decreased sensory input flowing into the thalamocortical network, as modulated by the eyes open and eyes closed states.

CONCLUSION

The results provide further evidence for alterations in brain electric activity that may underlie the development of neuropathic pain following SCI.

Stretching globular polymers. I. Single chains

We review the force-extension behavior of polymers collapsed in poor solvent, modified to include the effects of semiflexibility and considered for globules with "ordered" and "disordered" internal structures. A series of ordered globules is used as a model for the unbinding of a disordered globule beneath its glass transition and for multiple-repeat proteins such as the poly-Ig-domain titin used in atomic force microscopy studies. These single-chain results form the foundation for the treatment of cross-linked networks of globular polymers.

Nationwide outbreak of listeriosis due to contaminated meat

We used molecular subtyping to investigate an outbreak of listeriosis involving residents of 24 US states. We defined a case as infection with Listeria monocytogenes serotype 4b yielding one of several closely related patterns when subtyped by pulsed-field gel electrophoresis. Patients infected with strains yielding different patterns were used as controls. A total of 108 cases were identified with 14 associated deaths and four miscarriages or stillbirths. A case-control study implicated meat frankfurters as the likely source of infection (OR 17.3, 95% CI 2.4-160). The outbreak ended abruptly following a manufacturer-issued recall, and the outbreak strain was later detected in low levels in the recalled product. A second strain was recovered at higher levels but was not associated with human illness. Our findings suggest that L. monocytogenes strains vary widely in virulence and confirm that large outbreaks can occur even when only low levels of contamination are detected in sampled food. Standardized molecular subtyping and coordinated, multi-jurisdiction investigations can greatly facilitate detection and control of listeriosis outbreaks.

Stretching globular polymers. II. Macroscopic cross-linked networks

We expand upon the results for the force-extension behavior of single-collapsed polymer chains to consider the mechanical response of networks of cross-linked globular polymers in poor solvent. Force-strain curves are obtained under the affine deformation approximation for networked globules with both disordered and ordered globule conformations. Due to their large stored lengths, these networks would be capable of reaching extremely large strains. They also show anomalous nonmonotonic force-strain response, as a consequence of the nonmonotonic force-extension curves of their constituent globules. Finally, we consider the stability of ordered and disordered globules in these networks and propose means taken from biological and colloid science to stabilize networked globules.

Using independent component analysis to remove artifact from electroencephalographic measured during stuttered speech

The electro-encephalographic (EEG) activity of people who stutter could provide invaluable information about the association of neural processing and stuttering. However, the EEG has never been adequately studied during speech in which stuttering naturally occurs. This is owing, in part, to the masking of the EEG signal by artifact from sources such as the speech musculature and from ocular activity. The aim of this paper was to demonstrate the ability of independent component analysis (ICA) to remove artifact from the EEG of stuttering children recorded while they are speaking and stuttering. The EEG of 16 male children who stuttered and 16 who did not stutter was recorded during a reading task. The recorded EEG that contained artifact was then subjected to ICA. The results demonstrated that the EEG assessed during stuttered speech had substantially more noise than the EEG of speech that did not contain stuttering (p < 0.01). Furthermore, it was shown that ICA could effectively remove this artifact in all 16 children (p < 0.01). The results from one child highlight the findings that ICA can be used to remove dominant artifact that has prevented the study of EEG activity during stuttered speech in children.

Levels of brain wave activity (8-13 Hz) in persons with spinal cord injury

STUDY DESIGN

Brain wave activity in people with spinal cord injury (SCI) was compared to brain wave activity in able-bodied controls.

OBJECTIVES

To investigate whether a spinal injury results in changes in levels of brain wave activity in the 8-13 Hz spectrum of the electroencephalography (EEG).

SETTING

Sydney, Australia.

METHODS

Monopolar, multichannel EEG assessment was completed for 20 persons with SCI and 20 able-bodied, sex- and age-matched controls. A total of 14 channels of EEG were measured across the entire scalp for all participants. Comparisons between the able-bodied and SCI participants were made across the frontal, central, parietal, occipital and temporal regions. Comparisons were also made for impairment level, that is, between participants with tetraplegia and paraplegia.

RESULTS

Compared to the able-bodied controls, consistently reduced brain wave activity (measured by magnitude and peak amplitude) in the 8-13 Hz component of the EEG occurred in persons with SCI across all regions and sites, and differences were larger in the central, parietal and occipital sites. The SCI group also had consistently lower frequencies than the able-bodied controls. Furthermore, the subgroup of SCI participants with tetraplegia generally had significantly reduced brain activity (magnitude and peak amplitude) compared with the paraplegic subgroup and able-bodied controls.

CONCLUSIONS

The findings of this research enhance our understanding of changes in brain wave activity that could be associated with deafferentation that occurs following SCI, as well as provide essential data on the potential of SCI persons to use a 'hands free' environmental control system that is based upon 8-13 Hz brain activity.

Energy balance of human locomotion in water

In this paper a complete energy balance for water locomotion is attempted with the aim of comparing different modes of transport in the aquatic environment (swimming underwater with SCUBA diving equipment, swimming at the surface: leg kicking and front crawl, kayaking and rowing). On the basis of the values of metabolic power (E), of the power needed to overcome water resistance (Wd) and of propelling efficiency (etaP=Wd/Wtot, where Wtot is the total mechanical power) as reported in the literature for each of these forms of locomotion, the energy cost per unit distance (C=E/v, where v is the velocity), the drag (performance) efficiency (etad=Wd/E) and the overall efficiency (etao=Wtot/E=etad/etaP) were calculated. As previously found for human locomotion on land, for a given metabolic power (e.g. 0.5 kW=1.43 l.min(-1) VO2) the decrease in C (from 0.88 kJ.m(-1) in SCUBA diving to 0.22 kJ.m(-1) in rowing) is associated with an increase in the speed of locomotion (from 0.6 m.s(-1) in SCUBA diving to 2.4 m.s(-1) in rowing). At variance with locomotion on land, however, the decrease in C is associated with an increase, rather than a decrease, of the total mechanical work per unit distance (Wtot, kJ.m(-1)). This is made possible by the increase of the overall efficiency of locomotion (etao=Wtot/E=Wtot/C) from the slow speeds (and loads) of swimming to the high speeds (and loads) attainable with hulls and boats (from 0.10 in SCUBA diving to 0.29 in rowing).

Sequence of Plasmodium falciparum chromosomes 1, 3-9 and 13

Since the sequencing of the first two chromosomes of the malaria parasite, Plasmodium falciparum, there has been a concerted effort to sequence and assemble the entire genome of this organism. Here we report the sequence of chromosomes 1, 3-9 and 13 of P. falciparum clone 3D7--these chromosomes account for approximately 55% of the total genome. We describe the methods used to map, sequence and annotate these chromosomes. By comparing our assemblies with the optical map, we indicate the completeness of the resulting sequence. During annotation, we assign Gene Ontology terms to the predicted gene products, and observe clustering of some malaria-specific terms to specific chromosomes. We identify a highly conserved sequence element found in the intergenic region of internal var genes that is not associated with their telomeric counterparts.