Effect of prism adaptation on left dichotic listening deficit in neglect patients: glasses to hear better?

Unilateral neglect is a disabling syndrome frequently observed following right hemisphere brain damage. Symptoms range from visuo-motor impairments through to deficient visuo-spatial imagery, but impairment can also affect the auditory modality. A short period of adaptation to a rightward prismatic shift of the visual field is known to improve a wide range of hemispatial neglect symptoms, including visuo-manual tasks, mental imagery, postural imbalance, visuo-verbal measures and number bisection. The aim of the present study was to assess whether the beneficial effects of prism adaptation may generalize to auditory manifestations of neglect. Auditory extinction, whose clinical manifestations are independent of the sensory modalities engaged in visuo-manual adaptation, was examined in neglect patients before and after prism adaptation. Two separate groups of neglect patients (all of whom exhibited left auditory extinction) underwent prism adaptation: one group (n = 6) received a classical prism treatment ('Prism' group), the other group (n = 6) was submitted to the same procedure, but wore neutral glasses creating no optical shift (placebo 'Control' group). Auditory extinction was assessed by means of a dichotic listening task performed three times: prior to prism exposure (pre-test), upon prism removal (0 h post-test) and 2 h later (2 h post-test). The total number of correct responses, the lateralization index (detection asymmetry between the two ears) and the number of left-right fusion errors were analysed. Our results demonstrate that prism adaptation can improve left auditory extinction, thus revealing transfer of benefit to a sensory modality that is orthogonal to the visual, proprioceptive and motor modalities directly implicated in the visuo-motor adaptive process. The observed benefit was specific to the detection asymmetry between the two ears and did not affect the total number of responses. This indicates a specific effect of prism adaptation on lateralized processes rather than on general arousal. Our results suggest that the effects of prism adaptation can extend to unexposed sensory systems. The bottom-up approach of visuo-motor adaptation appears to interact with higher order brain functions related to multisensory integration and can have beneficial effects on sensory processing in different modalities. These findings should stimulate the development of therapeutic approaches aimed at bypassing the affected sensory processing modality by adapting other sensory modalities.

[Orion (Outbreak Reports and Intervention studies of Nosocomial Infection) used for evaluating interventions and investigations of nosocomial infection outbreaks]. / Orion (Outbreak Reports and Intervention Studies of Nosocomial Infection) pour l'évaluation des interventions et des investigations d'épidémie dans le domaine des infections nosocomiales.

INTRODUCTION: British colleagues have developed the Outbreak Reports and Intervention studies of Nosocomial Infection (Orion) guidelines with the aim to promote transparency of publications in the field of health-care associated infections and particularly for reports of outbreak investigation or intervention studies. The aim of this study was to translate the Orion criteria and to promote their use in France. RESULTS: The Orion guidelines include a checklist of 22 commented items related to the title, abstract, introduction, methods, results, and discussion sections of a scientific article. Specific points for each item are developed to enhance its relevance. CONCLUSION: The use of Orion guidelines by authors and editors should be encouraged and should improve the quality of standards in research, intervention studies, and publications on nosocomial infections and health-care associated infections.

Leptospirosis in French Polynesia: 11 years of surveillance data, 2007-2017.

Leptospirosis is a worldwide zoonosis with higher incidence in tropical areas and is a neglected disease in the Pacific region. French Polynesia (FP) is a French overseas territory located in the South Pacific. Data on the epidemiology in FP are scarce. In this study, we describe our understanding of leptospirosis epidemiology in FP and discuss the prospects concerning this disease and its surveillance to better address preventive actions. We report 11 years of surveillance data between 1 January 2007 and 31 December 2017. Over the study period, 1356 confirmed and probable leptospirosis cases were reported. The mean annual incidence rate was 46.0 (95% confidence interval, 43.6-48.5) cases per 100 000 inhabitants. We registered 864 (63.7%) hospitalizations; of these, at least 270 (19.9%) were in the intensive care unit, and 24 patients (1.8%) died. Even if the incidence of leptospirosis is lower in FP compared to most of other Pacific countries and territories, our data confirm that the disease is highly endemic in FP. Despite all the preventive measures taken, leptospirosis remains a major public health concern in FP, thus highlighting the need to maintain intensive leptospirosis surveillance, medical staff training and provision of information to the general population.

Incidence of methicillin-resistant Staphylococcus aureus nosocomial infections in intensive care units in Lyon University hospitals, France, 2003-2006.

We describe the trends in the incidence of methicillin-resistant Staphylococcus aureus nosocomial infection in intensive care units in Lyon hospitals from January 1, 2003, through December 31, 2006. The incidence rate decreased from 1.77 cases per 100 ICU patients in 2003 to 1.16 cases per 100 ICU patients in 2006, a reduction of 38.0% (P = .05).

Cross-modal processing of auditory-visual stimuli in a no-task paradigm: a topographic event-related potential study.

OBJECTIVE: The aim of this study was to investigate in healthy adults the electrophysiological correlates of auditory-visual interactions involved in perception of bimodal events in a no-task paradigm. METHODS: Event-related potentials were recorded in response to unimodal auditory (A), unimodal visual (V) and bimodal (AV) stimuli. Cross-modal interactions were estimated using the additive [AV-(A+V)] model. RESULTS: The spatio-temporal analysis of ERPs and scalp current densities revealed several interaction patterns occurring at both early and late stages of sensory cortical processing: (1) amplitude decrease of the unimodal auditory N1 wave as early as 55ms, (2) amplitude increase of the unimodal auditory P2 wave from 150 to 195ms concomitant with new neural activity over the right fronto-temporal region, and (3) amplitude increase of the late unimodal visual response within 245-350ms post-stimulus. CONCLUSIONS: Our study provides evidence that several patterns of cross-modal interactions can be generated even if no task is required from subjects. SIGNIFICANCE: The paradigm used here can thus be utilized for studying the maturation of the cross-modal processes in young children and in children with pathological development.

[Treatment interruption in HIV infected patients: clinical and biological evolution]. / Interruption thérapeutique chez des patients infectés par le virus de l'immunodéficience humaine: évolution clinique et biologique.

OBJECTIVE: The authors had for aim to evaluate the clinical and biological evolution in HIV-infected patients with viraemia lower than 30,000 copies/mL having decided to interrupt their treatment. PATIENTS AND METHODS: Patients with highly active antiretroviral therapy (HAART) for more than 3 months followed by treatment interruption longer than 1 month were included in a retrospective analysis. RESULTS: Forty-six patients having stopped treatment between November 1999 and July 2003 were included. The median duration of treatment interruption was 9.5 months. During the study, no clinical event occurred for 21 patients, and at least 1 clinical event occurred for the 25 others. The median CD4(+) cell counts (CD4) before and at the end of treatment interruption were 597/mm(3) and 437/mm(3), respectively (P<0.001). The median values of viral load before and at the end of treatment interruption were <50 and 23749 copies/mL, respectively (P<0.001). Among the 26 patients having started a new HAART, pre-treatment interruption and post-new HAART median CD4 (with a median delay after HAART of 9.7 months) were 548 and 432.5/mm(3) (P=0.02). Pre-treatment interruption and post-new HAART median viral load were 131.5 and 94.5 copies/mL (NS). CONCLUSIONS: Treatment interruption must be used with caution in spite of the absence of virological impact, because CD4 cell count after new HAART is lower than CD4 preceding treatment interruption. Treatment interruption is contraindicated for patients with AIDS. Physicians must carefully follow other patients who decide on a treatment interruption.

Surgical site infection after valvular or coronary artery bypass surgery: 2008-2011 French SSI national ISO-RAISIN surveillance.

BACKGROUND: Multisite information regarding surgical site infection (SSI) rates for cardiac surgery programmes is not widely available. Ward characteristics that may affect outcomes have not been analysed previously. AIM: To determine individual- and ward-level factors associated with SSI occurrence after coronary artery bypass grafting (CABG) and valvular surgery. METHODS: A dataset from the French national SSI database ISO-RAISIN 2008-2011 was used. Only adult patients were included. A standardized questionnaire was completed for each patient who underwent surgery, and patients with and without SSI were characterized. Patients and ward risk factors for SSI were analysed using a multilevel logistic regression model with SSI as binary outcome (two levels: patient and ward). RESULTS: Out of 8569 patients from 39 wards, the SSI rate was 2.2%. Micro-organisms were isolated in 144 patients (74%): 35% coagulase-negative staphylococci (N = 51), 23% Staphylococcus aureus (N = 33), 6% Escherichia coli (N = 8). Higher probability of SSI was associated with the duration of preoperative hospitalization, the duration of follow-up, the duration of surgery >75th percentile and the SSI rate in the surgery ward. The residual heterogeneity between wards (median odds ratio: 1.53) was as relevant as duration of preoperative hospitalization (odds ratio: 1.57). CONCLUSION: Although patient risk factors were more strongly associated with SSI occurrence, this study provided evidence for the existence of a ward-level effect. This should be taken into account when considering possible corrective interventions.

Neurophysiological mechanisms of auditory selective attention in humans.

This chapter reviews the main data on the physiological substrates of auditory selective attention and their contribution to theoretical models of cognitive psychology. While event-related potentials, magnetoencephalography, and more recently neuroimaging techniques have provided fundamental information on the neural correlates of attention in the central cortical system, measurements of the frequency-following responses in the brainstem and evoked otoacoustic emissions at the cochlea strongly suggest attentional phenomena at the auditory periphery. We propose an adaptive filtering mechanism for selective auditory attention that can be flexibly and dynamically tuned depending on the attentional demand.

Sustained-release diltiazem compared with atenolol monotherapy for mild to moderate systemic hypertension.

The daily administration of 240 to 360 mg of diltiazem lowered blood pressure in a dose-related pattern similar to that seen in patients taking a daily dosage of 50 to 100 mg of atenolol. Sustained-release diltiazem was administered twice daily and atenolol once. Goal blood pressure was defined as less than 90 mm Hg or a reduction of greater than or equal to 10 mm Hg for patients with baseline pressures of 95 to 99 mm Hg in the supine position and was achieved in 60% of diltiazem-treated and 63% of atenolol-treated patients. The mean diltiazem dosage at the end of the study was 329 mg daily; for atenolol it was 80 mg daily. Adverse reactions considered possibly or probably drug related were reported by 26% of diltiazem patients and 38% of atenolol patients. Although both drugs were associated with a slower heart rate, atenolol patients showed a significantly greater negative chronotropic effect. Diltiazem, in a sustained-release form taken twice daily, is as effective as atenolol as a sole antihypertensive agent. It has a favorable side-effect profile and may be a useful alternative antihypertensive medication compared with existing beta-blocker therapy with atenolol.

Auditory cortex activation in deaf subjects during cochlear electrical stimulation. Evaluation by functional magnetic resonance imaging.

RATIONALE AND OBJECTIVES: The authors detect activation in the auditory cortex during cochlear electrical stimulation in deaf patients using functional magnetic resonance (MR) imaging. METHODS: Stimulating electrode was inserted gently under local anesthesia close to the round window membrane of the cochlea in seven cochlear implant candidates. These patients suffered from postlingual-acquired deafness. Four patients were stimulated above the electrical perception threshold and three below the electrical discomfort threshold. Functional scans (fast low-angle shot 91 mseconds/60 mseconds) were acquired in an oblique axial plane running parallel to the sylvian fissure. Four consecutive series of six images were obtained in 6 minutes. The acquisition time of each image was 15 seconds. RESULTS: During electrical cochlear stimulation below the discomfort threshold, the three patients described "auditory" sensations with activation of the superior temporal regions. In two patients with electrical stimulation of the left ear, the maximum signal intensity increased by 8.42% in the right auditory cortex and 5.69% in the left. In one patient with a right electrical stimulation only the left cortex was activated. Electrical cochlear stimulation above the perception threshold induces no significant activation in the auditory cortex. CONCLUSION: Functioning MR imaging can detect activation in the auditory cortex during cochlear electrical stimulation in deaf patients using a conventional 1.5-tesla system in a routine hospital environment. Further studies are needed to investigate its usefulness in clinical practice.

Electrophysiological evidence for a shared representational medium for visual images and visual percepts.

Does mental imagery involve the activation of representations in the visual system? Systematic effects of imagery on visual signal detection performance have been used to argue that imagery and the perceptual processing of stimuli interact at some common locus of activity (Farah, 1985). However, such a result is neutral with respect to the question of whether the interaction occurs during modality-specific visual processing of the stimulus. If imagery affects stimulus processing at early, modality-specific stages of stimulus representation, this implies that the shared stimulus representations are visual, whereas if imagery affects stimulus processing only at later, amodal stages of stimulus representation, this implies that imagery involves more abstract, postvisual stimulus representations. To distinguish between these two possibilities, we repeated the earlier imagery-perception interaction experiment while recording event-related potentials (ERPs) to stimuli from 16 scalp electrodes. By observing the time course and scalp distribution of the effect of imagery on the ERP to stimuli, we can put constraints on the locus of the shared representations for imagery and perception. An effect of imagery was seen within 200 ms following stimulus presentation, at the latency of the first negative component of the visual ERP, localized at the occipital and posterior temporal regions of the scalp, that is, directly over visual cortex. This finding provides support for the claim that mental images interact with percepts in the visual system proper and hence that mental images are themselves visual representations.

Cerebral mechanisms underlying orienting of attention towards auditory frequency changes.

Brain mechanisms underlying detection of auditory frequency changes were studied with event-related potentials (ERPs) in 14 human subjects discriminating visual stimuli. Scalp-current density mapping revealed bilateral components of mismatch negativity (MMN) in frontal and auditory cortices. Deviance-related activations in frontal and temporal cortex began to be significant at 94 ms and 154 ms in the right hemisphere, and at 128 ms and 132 ms in the left hemisphere. The magnitude of MMN-neuroelectric currents from the left temporal cortex correlated significantly (r = -0.56, p < 0.05) with distraction caused by MMN-eliciting deviant tones. These results suggest a complex cerebral circuitry involved in frequency change detection and strongly support the role of this circuitry in driving attention involuntarily towards potentially relevant frequency changes in the acoustic environment.

Maturation of frontal and temporal components of mismatch negativity (MMN) in children.

The mismatch negativity (MMN) response of auditory ERPs in adults appears to result from several overlapping components involving both frontal and temporal brain areas. Our aim was to test whether a similar configuration could be observed in children, and to examine the maturation rates of the different components. MMN (standard tones: 1000 Hz, deviants: 1100 Hz) was recorded from 28 scalp electrodes in 24 healthy children aged from 5 to 10 and in eight adults for comparison. Scalp current density analysis revealed both temporal and frontal components in children of all ages as well as in adults. Moreover the amplitudes of the temporal components were significantly greater in children than in adults, whereas the frontal components were similar at all ages. The results strongly suggest that MMN is mediated by at least two separate neural systems, and that the frontal system matures earlier than the sensory-specific system.

Early signs of visual categorization for biological and non-biological stimuli in humans.

In a previous experiment aimed at studying gender processing from faces, we had found unexpected early ERP differences (45-85 ms) in task-irrelevant stimuli between a condition in which the stimuli of each gender were delivered in separate runs, and a condition in which the stimuli of both genders were mixed. Similar effects were observed with hand stimuli. These early ERP differences were tentatively related to incidental categorization processes between male and female stimuli. The present study was designed to test the robustness of these early effects for faces, and to examine whether similar effects can also be generated between two classes of non-biological stimuli. We replicated the previous findings for faces, and found similar early differential effects (50-65 ms) for non-biological stimuli (grey and hatched geometrical shapes) only, however, when the two shape categories were separated by conspicuous visual characteristics. While these results can partly be explained by phenomena related to neuronal habituation in the visual cortex, they may also suggest the existence of coarse and automatic categorization processes for rapid distinction between two wide classes of stimuli with strong psychosocial significance for humans.

Auditory selective attention in the human cochlea.

According to current theories, auditory selective attention alters the sensory analysis of acoustic inputs only in the central auditory system. Despite numerous attempts, no evidence of attentional selection has been found in the auditory periphery. Measurements of evoked otoacoustic emissions (EOAEs) during a selective dichotic listening task showed that the EOAEs to tones in one ear had larger amplitude when attention was directed to this ear than when attention was directed to the opposite ear. The results indicate that genuine effects of auditory selective attention can be observed at the cochlear receptor.

Auditory distraction: event-related potential and behavioral indices.

OBJECTIVE: The aim of this study was to illuminate behavioral and event-related potential (ERP) effects of attentional orienting and reorienting obtained in a newly developed auditory distraction paradigm, to provide more precise indicators about the neural generators of the ERP effects using scalp current density (SCD) analysis, and to evaluate the stability of the distraction effects. METHODS: In two sessions separated by 25 days, 10 subjects were presented with tones being of short (200 ms) and long (400 ms) duration equiprobably; tones were of high-probability standard or of low-probability deviant frequency. In Distraction condition, subjects had to behaviorally discriminate short from long tones. In Ignore condition, subjects were reading a book. Behavioral performance and multi-channel EEG were recorded. RESULTS: Task-irrelevant frequency deviations prolonged reaction times in the duration discrimination task by more than 35 ms and elicited the MMN and P3a components of the event-related potential. The P3a was followed by a negative deflection called RON (reorienting negativity). P3a and RON were absent in Ignore condition. All effects were found to be highly stable between sessions (product-moment correlations between 0.76 and 0.90). SCD analysis suggested frontal generators for P3a and for RON. CONCLUSIONS: It is demonstrated that small frequency deviations may yield distinct distraction effects in a tone duration discrimination task on a behavioral and on an electrophysiological level. Results support the hypothesis that frontal areas are involved in the exogenous orienting of attention (P3a) and in the reorienting of attention (RON). Due to the high stability of the deviance-related behavioral and ERP effects, this distraction paradigm may be utilized for clinical research.

Precautions in topographic mapping and in evoked potential map reading.

First, we consider the main points that must be addressed when constructing topographic maps: types of projection, methods of interpolation, number and locations of recording electrodes, and color scales. Data integrity and precautions in map interpretation are then examined for the case of evoked potential data.

Sequential colour mapping system of brain potentials.

We present a colour mapping system for the visualization of both the spatial scalp distribution and the temporal evolution of brain potentials. The system is applicable to recordings of auditory, visual and somatosensory potentials. It uses a Tektronix 4113 colour terminal connected to a Solar 16 (SEMS) mini-computer. The brain potentials are recorded on up to 16 scalp electrodes. The gain and the baseline are corrected separately on each channel. At each point of the scalp the potential is reconstructed by a linear interpolation of the measured potentials of the four nearest electrodes. Simultaneously n2 (1 less than n less than 8) colour maps can be presented on the screen. This allows the study of the temporal evolution of full scalp evoked potentials. The user chooses the two extreme latencies defining the time window to be explored and the latencies of the maps are regularly time-spaced within this window. In a typical case, in which four maps are desired, the latencies of the maps can be chosen independently. The 16-colour palette is predetermined but the user has three possibilities to establish the correspondence between the electrical potential and the colours. Examples are shown in the visual and somatosensory stimulation modalities. The advantages and limitations of such a representation are discussed.

[Factors associated with the late management of HIV-infected patients: literature review]. / Facteurs associés à une prise en charge tardive des patients infectés par le VIH: revue de la littérature.

In the United States, Australia and Europe, many HIV infected individuals are still diagnosed and/or treated late in the course of the disease. This literature review of studies published over a ten year period between 1993 and 2003 has identified the following principle factors associated with the late diagnosis of HIV: male gender, aged older than 45 years, heterosexual intercourse, the lack of previous screening. It also identified the factors linked to the delay in beginning anti-retroviral treatment as being male gender, the lack of awareness or denial of the possibility of HIV infection, intravenous drug use, lack of post-screening follow-up or counseling, lack of social protection, and the lack of regular medical visits and care. Early detection and suitable early treatment of the HIV virus are the main determining factors which will effectively contribute to the control and maintenance of the virus in as much as they are focused upon these particular at-risk populations.