Comparative study of open, laparoscopic and endoscopic treatments of intermediate grade vesicoureteral reflux in children.

BACKGROUND: Low-grade vesicoureteral-reflux (VUR) are rather treated by endoscopic injection, whereas open or laparoscopic procedures are mainly performed for high-grade VURs. Management of intermediate grades is controversial and no study focused on grade III to date. This study aims to compare the results of open, laparoscopic, and endoscopic approaches in children with grade III VUR. METHODS: A multicenter comparative retrospective study included children with grade III VUR operated for febrile urinary tract infections (UTIs) from 2007 to 2016. Children without UTI, with reflux of other grades, neurological bladder, duplex system, posterior urethral valves, and bladder exstrophy were excluded. Success was defined as no recurrence of febrile UTI and was presented as event-free survival curves. RESULTS: Out of 806 children operated of VUR, 171 met the inclusion criteria (114 females). Seventy-seven children (45%) underwent an open Cohen procedure, 35 (21%) a laparoscopic Lich-Gregoir and 59 (34%) a submucosal endoscopic injection according to the centers' preference. The mean follow-up was 64 months (24-132). Groups were not different for age, sex, and circumcision status. Compared to Cohen procedure, recurrences of febrile UTI were more frequent after laparoscopic treatment (p = 0,02, 8/35) and endoscopic treatment (p = 0.001, 16/59). Redosurgery was also more frequent after laparoscopy (n = 2) and endoscopic injection (n = 14) than after open surgery (n = 0, p < 0.001). CONCLUSION: Recurrent febrile UTIs and redosurgery are more frequent after endoscopic and laparoscopic procedures in grade III VUR than open reimplantation. Whether the lower morbidity of laparoscopic or endoscopic approaches balances the risk of recurrent febrile UTI remains to be determined for intermediate grade reflux.

Malignancy after Augmentation Enterocystoplasty: A Nationwide Study of Natural History, Prognosis and Oncogene Panel Analysis.

PURPOSE: We report the natural history and prognosis of tumors after augmentation enterocystoplasty, with a molecular analysis using an oncogene panel to search for potential targeted therapies. MATERIALS AND METHODS: This multicenter, nationwide, retrospective study included 16 patients. A panel of 21 clinically relevant oncogenes was tested on archival tumor specimens using next-generation sequencing. Survival rate was the main clinical outcome and sequences were compared to the reference genome for the genetic outcome. RESULTS: Augmentation enterocystoplasties were performed mainly for congenital neurogenic bladder and bladder exstrophy at a median patient age of 17 years (range 4 months to 45 years). Most of the malignancies were diagnosed because of clinical manifestations, with a median latency period of 20 years. Adenocarcinomas were mainly found after gastrocystoplasty, whereas urothelial cell carcinomas were typically found after colocystoplasty. Of the 16 patients 13 were diagnosed at an advanced stage of the disease (positive lymph nodes in 7, distant metastases in 6). The overall 1-year survival rate was 56%. Only 3 patients remained disease-free at a median followup of 70 months. Of the 9 tumors with analyzable DNA 4 were wild-type and 5 harbored missense mutations (KIT-p.Pro573Ser, PDGFRA-p.Glu587Lys, KRAS-p.Gly12Asp, ERBB4p.Arg484Lys, CTNNB1-p.Ser37Phe and p.Ser47Asn). CONCLUSIONS: Malignancy after augmentation enterocystoplasty is diagnosed late with frequent metastases and a very low 1-year survival rate. More than half the tested samples harbored missense mutations in oncogenes accessible to targeted therapies. An international collaboration to enlarge the genetic panel analysis of these tumors may offer new therapeutic hope to patients.

Morphology and genetics reveal an intriguing pattern of differentiation at a very small geographic scale in a bird species, the forest thrush Turdus lherminieri.

Mobile organisms are expected to show population differentiation only over fairly large geographical distances. However, there is growing evidence of discrepancy between dispersal potential and realized gene flow. Here we report an intriguing pattern of differentiation at a very small spatial scale in the forest thrush (Turdus lherminieri), a bird species endemic to the Lesser Antilles. Analysis of 331 individuals from 17 sampling sites distributed over three islands revealed a clear morphological and genetic differentiation between these islands isolated by 40-50 km. More surprisingly, we found that the phenotypic divergence between the two geographic zones of the island of Guadeloupe was associated with a very strong genetic differentiation (Fst from 0.073-0.153), making this pattern a remarkable case in birds given the very small spatial scale considered. Molecular data (mitochondrial control region sequences and microsatellite genotypes) suggest that this strong differentiation could have occurred in situ, although alternative hypotheses cannot be fully discarded. This study suggests that the ongoing habitat fragmentation, especially in tropical forests, may have a deeper impact than previously thought on avian populations.

Biliary cirrhosis and sepsis are two risk factors of failure after surgical repair of major bile duct injury post-laparoscopic cholecystectomy.

BACKGROUND: Major bile duct injury (MBDI) remains frequent after laparoscopic cholecystectomy (LC) reaching 0.3 to 0.6 % and is associated with a significant mortality rate. The aim of this study was to retrospectively analyze the factors likely to influence the long-term results of surgical repair for MBDI occurring after LC. METHODS: Medical records of patients referred to our referral center from January 1992 to January 2010 for management of bile duct injury following LC were retrospectively analyzed, and patients with MBDI were identified. Clinicopathological factors likely to influence long-term results after surgical repair were assessed by univariate and multivariable analysis. RESULTS: During the study period, 38 patients were treated for MBDI. These 38 patients underwent Roux-en-Y hepaticojejunostomy (HJ) or HJ revision in 25 (66 %) and 13 (34 %) cases, respectively. The median follow-up period was 93 (26-204) months. A Clavien-Dindo post-operative morbidity class >3 occurred in 10 (26 %) cases and was independently associated with a surgical repair performed during a sepsis period (OR = 102.5; IC 95 % [7.12; 11,352], p < 0.007). Long-term results showed that biliary strictures occurred in 5 (13 %) cases and were associated with sepsis (p < 0.006), liver cirrhosis (p < 0.002) and post-operative complications (p < 0.012). Multivariate analysis revealed that only liver cirrhosis remained predictive of stricture (OR = 26.4, 95 % CI [2; 1,018], p < 0.026). CONCLUSION: When MBDI occurs following LC, HJ seems to be the optimal treatment but should not be performed during a sepsis period. Long-term results are significantly altered by the presence of a biliary cirrhosis at time of repair.

First Report of 'Candidatus Liberibacter solanacearum' in Carrot in France.

In summer 2012, carrot (Daucus carota L.) plants displaying symptoms of leaf yellowing, stunting and proliferation of dwarfed shoots with bushy tops, and a dense hairy growth of secondary roots were observed. Symptomatic carrots were collected from three fields used for seed production and located in Region Centre of France near Orléans. The presence of psyllids (Psyllidae) in one of the fields was reported but they were not clearly identified. Fifty percent of the field was infected. Due to a large amount of plant debris, the harvested seeds were difficult to separate and the germination rate was low (from 10 to 77%), rendering them unmarketable. The symptoms observed were similar to those described for carrots infected by Aster yellows phytoplasma and 'Candidatus Liberibacter solanacearum' in Europe (3). Total DNA was extracted from petiole and root tissue of 16 symptomatic and 6 asymptomatic carrots (cv. Amsterdam, CAC3075), 2 samples of black nightshade leaves (Solanum nigrum) collected from the same fields, and 2 samples of carrot plants (cv Berlicum) grown in a high containment greenhouse, using a cetyl trimethyl ammonium bromide (CTAB) buffer extraction method. All DNA extracts were tested for phytoplasmas (1) and for 'Ca. L. solanacearum' by real-time PCR (2). DNA extracts were also tested for 'Ca. L. solanacearum' by PCR using primer pairs OA2/OI2c and CL514F/R to amplify a portion of 16S rDNA and rpIJ/rpIL ribosomal protein genes, respectively (4). DNA from greenhouse carrot plants yielded no amplicon with all PCR. Phytoplasma was not detected in any of the tested samples. However, amplification was observed with the real-time PCR assay for 'Ca. L. solanacearum' (2) for all DNA samples extracted from symptomatic and asymptomatic field carrots (cycle threshold [ct] values between 16.75 and 30.59), and from S. nigrum (ct between 31.62 and 33.25). For field carrot DNA, a 1,168-bp 16S rDNA fragment and a 669-bp rpIJ/rpIL fragment were amplified whereas DNA from S. nigrum yielded no amplicon. Four amplicons obtained from these PCR assays with both primer pairs from symptomatic carrot samples were sequenced directly (Beckmann Coulter Genomics, Grenoble, France). BLAST analysis of the 16S rDNA sequences (KF357911) showed 99% nucleotide identity to those of 'Ca. L. solanacearum' amplified from carrot in Finland (GU373049). The rpIJ/rpIL nucleotide sequences (KF357912) were 99% identical to sequences of the analogous rpIJ/rpIL 'Ca. L. solanacearum' ribosomal protein gene from carrot in Spain (JX308305). These results confirmed the presence of 'Ca. L. solanacearum' in all symptomatic and asymptomatic carrot sampled in Region Centre, France. To our knowledge, this is the first report of this pathogen in carrot in France. These results, in addition to those previously obtained (4), suggest a wider distribution of 'Ca. L. solanacearum' than previously reported in Europe and should lead plant health managers to consider this pathogen as an emerging threat. References: (1) N. M. Christensen et al. Mol. Plant Microbe Interact. 17:1175, 2004. (2) W. Li et al. J. Microbiol. Methods 78:59, 2009. (3) J. E. Munyaneza et al. Plant Dis. 94:639, 2010. (4) J. E. Munyaneza et al. Plant Dis. 96:453, 2012.

Circumcision and Risk of Febrile Urinary Tract Infection in Boys with Posterior Urethral Valves: Result of the CIRCUP Randomized Trial.

BACKGROUND: Boys with posterior urethral valves (PUVs) have an increased risk of febrile urinary tract infections (fUTIs). Circumcision is believed to reduce the risk of fUTIs in boys, although there are no randomized trials demonstrating this. OBJECTIVE: To determine the effect of circumcision on the risk of fUTIs in boys with PUVs. DESIGN, SETTING, AND PARTICIPANTS: A clinical randomized trial that ran between August 2012 and July 2017 was conducted. The trial was multicentric, including 13 referral centers for pediatric urology. Male boys, aged 1-28 d, diagnosed with posterior urethral valves, confirmed by voiding cystogram, were included. The exclusion criteria included presence of a genital malformation contraindicating performing a circumcision. INTERVENTION: Participants were randomized to neonatal circumcision + antibiotic prophylaxis (CATB) or antibiotic prophylaxis alone (ATB), and followed for 2 yr. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: The primary outcome was a risk of presenting fUTIs in each group. An fUTI was defined as fever (>38.5 °C) with evidence of pyuria and culture-proven infection on urinalysis, obtained by urethral catheterization or suprapubic aspiration. A bivariate analysis of the primary outcome was performed using the Kaplan-Meier method. RESULTS AND LIMITATIONS: In total, 91 patients were included: 49 in group CATB and 42 in group ATB. The probability of presenting an fUTI was 20% in group ATB versus 3% in group CATB. The hazard ratio of presenting an fUTI within 2 yr in the ATB group compared with that in the CATB group was 10.3 (95% confidence interval: 1.3-82.5). Sixty-four children (70.3%) had a complete follow-up at 2 yr of age. CONCLUSIONS: Circumcision significantly decreases the risk of presenting an fUTI in boys with PUVs. PATIENT SUMMARY: In this report, we compared, in a multicentric trial, the number of febrile urinary tract infections (UTIs) in boys with posterior urethral valves who had either antibiotic prophylaxis alone or antibiotic prophylaxis and circumcision. We found that those who had a circumcision had a significantly lower risk of febrile UTIs.

Consensus of travel direction is achieved by simple copying, not voting, in free-ranging goats.

For group-living animals to remain cohesive they must agree on where to travel. Theoretical models predict shared group decisions should be favoured, and a number of empirical examples support this. However, the behavioural mechanisms that underpin shared decision-making are not fully understood. Groups may achieve consensus of direction by active communication of individual preferences (i.e. voting), or by responding to each other's orientation and movement (i.e. copying). For example, African buffalo (Syncerus caffer) are reported to use body orientation to vote and indicate their preferred direction to achieve a consensus on travel direction, while golden shiners (Notemigonus crysoleucas) achieve consensus of direction by responding to the movement cues of their neighbours. Here, we present a conceptual model (supported by agent-based simulations) that allows us to distinguish patterns of motion that represent voting or copying. We test our model predictions using high-resolution GPS and magnetometer data collected from a herd of free-ranging goats (Capra aegagrus hircus) in the Namib Desert, Namibia. We find that decisions concerning travel direction were more consistent with individuals copying one another's motion and find no evidence to support the use of voting with body orientation. Our findings highlight the role of simple behavioural rules for collective decision-making by animal groups.

Decoding collective communications using information theory tools.

Organisms have evolved sensory mechanisms to extract pertinent information from their environment, enabling them to assess their situation and act accordingly. For social organisms travelling in groups, like the fish in a school or the birds in a flock, sharing information can further improve their situational awareness and reaction times. Data on the benefits and costs of social coordination, however, have largely allowed our understanding of why collective behaviours have evolved to outpace our mechanistic knowledge of how they arise. Recent studies have begun to correct this imbalance through fine-scale analyses of group movement data. One approach that has received renewed attention is the use of information theoretic (IT) tools like mutual information, transfer entropy and causation entropy, which can help identify causal interactions in the type of complex, dynamical patterns often on display when organisms act collectively. Yet, there is a communications gap between studies focused on the ecological constraints and solutions of collective action with those demonstrating the promise of IT tools in this arena. We attempt to bridge this divide through a series of ecologically motivated examples designed to illustrate the benefits and challenges of using IT tools to extract deeper insights into the interaction patterns governing group-level dynamics. We summarize some of the approaches taken thus far to circumvent existing challenges in this area and we conclude with an optimistic, yet cautionary perspective.

A chemogenomic approach to identify personalized therapy for patients with relapse or refractory acute myeloid leukemia: results of a prospective feasibility study.

Targeted next-generation sequencing (tNGS) and ex vivo drug sensitivity/resistance profiling (DSRP) have laid foundations defining the functional genomic landscape of acute myeloid leukemia (AML) and premises of personalized medicine to guide treatment options for patients with aggressive and/or chemorefractory hematological malignancies. Here, we have assessed the feasibility of a tailored treatment strategy (TTS) guided by systematic parallel ex vivo DSRP and tNGS for patients with relapsed/refractory AML (number NCT02619071). A TTS issued by an institutional personalized committee could be achieved for 47/55 included patients (85%), 5 based on tNGS only, 6 on DSRP only, while 36 could be proposed on the basis of both, yielding more options and a better rationale. The TSS was available in <21 days for 28 patients (58.3%). On average, 3 to 4 potentially active drugs were selected per patient with only five patient samples being resistant to the entire drug panel. Seventeen patients received a TTS-guided treatment, resulting in four complete remissions, one partial remission, and five decreased peripheral blast counts. Our results show that chemogenomic combining tNGS with DSRP to determine a TTS is a promising approach to propose patient-specific treatment options within 21 days.

Management of patients presenting with generalized musculoskeletal pain and a suspicion of Lyme disease.

Lyme disease is caused by bacteria of the B. burgdorferi sensu lato complex, and can give polymorphic clinical manifestations that can affect several organs such as the skin, the central nervous system, or the joints. In recent years, patients' associations and physicians have been supporting the hypothesis that this infection would manifest as chronic generalized musculoskeletal pain symptoms, named "chronic Lyme disease". Fibromyalgia is a clinical presentation characterized by chronic generalized musculoskeletal pain with a major impact on quality of life and social and psychological functioning. We analyzed existing literature data on pain syndromes associated with Lyme disease (post-treatment Lyme disease syndrome) or tick bites (polymorphic symptoms after a tick bite). We also analyzed existing data on the diagnosis, pathophysiology, and treatment of fibromyalgia. Our review shows that post-treatment Lyme disease syndrome has characteristics very close to post-infectious fibromyalgia. On the other hand, patients presenting for Lyme disease screening because of chronic generalized musculoskeletal pain symptoms after a tick bite should also be screened for fibromyalgia to allow appropriate management. Antibiotics are not recommended here.

Lack of linkage and association of adrenomedullin and its receptor genes in French Caucasian rheumatoid arthritis trio families.

OBJECTIVE: Rheumatoid arthritis (RA) is characterized by hyperplasia of fibro-blast-like synoviocytes (FLSs), in part due to apoptosis resistance. Adrenomedullin, an anti-apoptotic peptide, is secreted more by RA than osteoarthritis FLSs. Adrenomedullin binds to a heterodimeric functional receptor, of calcitonin receptor-like receptor (CRLR) coupled with a receptor activity-modifying protein-2 (RAMP-2), which is also overexpressed by rheumatoid synoviocytes. Since adrenomedullin decreases RA FLS apoptosis, possibly contributing to the development of pannus, study of adrenomedullin and its receptor genes might reveal a linkage and association in French Caucasian RA trio families. METHODS: Within each of 100 families, one RA-affected patient and both parents underwent genotyping for polymorphisms of adrenomedullin, CRLR and RAMP-2, by PCR-restricted fragment-length polymorphism (RFLP) or Taqman 5' allelic discrimination assay. Statistical analysis relied on the transmission disequilibrium test, the affected family-based controls and the genotype relative risk. Haplotypes of CRLR were inferred, and linkage and association studies were performed. RESULTS: No significant transmission disequilibrium or association between the three genes and RA was observed. CRLR haplotypes revealed two major haplotypes, but no significant linkage with RA. CONCLUSION: Our findings provided no significant linkage or association of adrenomedullin and CRLR-RAMP-2 genes with RA in the studied trio families. The two CRLR polymorphisms rs3771076 and rs3771084 should be investigated in larger samples.

The MMP2 rs243865-T allele is not a major genetic factor for rheumatoid arthritis in the French Caucasian population.

The MMP2 rs243865-T allele was recently suggested to be associated with rheumatoid arthritis (RA) in a case-control study. MMP2 is a positional RA candidate gene. Our aim was to test rs243865 in a French family based study. No significant result was shown. The MMP2 rs243865-T allele is not a major rheumatoid arthritis genetic factor in this population.

Influence of ageing, grinding and preheating on the thermal behaviour of alpha-lactose monohydrate.

It is shown that the onset temperature and the magnitude of thermal events observed during DSC analyses of alpha-lactose monohydrate can be strongly affected by various treatments such as ageing, manual grinding and preheating (cycle of preliminary dehydration and rehydration). In the case of grinding and preheating, the change of dehydration pathways was further investigated by using a suitable combination of characterization techniques, including X-ray powder diffraction (XRPD) performed with a synchrotron source (allowing an accurate Rietveld analysis), scanning electron microscopy (SEM), laser particle size measurements, FTIR spectroscopy and (1)H NMR for the determination of beta-lactose contents in samples. It appeared that the dehydration mechanism is affected not only by a smaller particle size distribution, but also by residual anisotropic lattice distortions and by the formation of surface defects or high energy surfaces. The fusion-recrystallization process occurring between anhydrous forms of alpha-lactose at ca. 170 degrees C is not significantly affected by grinding, whereas a preheating treatment induces an unexpected large increase of the enthalpy associated with this transition. Our observations and interpretations confirm the important role of water molecules in the crystal cohesion of the title compound and illustrate the necessity to consider the history of each sample for a satisfactory understanding of the physical properties and the behaviour of this important pharmaceutical excipient.

[Semantic dementia: reflexions of a French working group for diagnostic criteria and constitution of a patient cohort]. / Démence sémantique: réflexions d'un groupe de travail pour des critères de diagnostic en français et la constitution d'une cohorte de patients.

Semantic dementia (SD) is a syndrome of progressive loss of semantic knowledge for objects and people. International criteria propose that SD be included in the frontotemporal lobar degeneration syndromes, with progressive non-fluent aphasia and frontotemporal dementia (FTD). However, several related syndromes have been defined that clinically and conceptually share both similarities and differences with SD: fluent progressive aphasia, progressive prosopagnosia, temporal variant of FTD. In order to establish a French consensus for the diagnosis and modalities of evaluation and follow-up of SD, a working group, composed of neurologists, neuropsychologists and speech-therapists, was established by the Groupe de réflexion sur les évaluations cognitives (GRECO). New criteria were elaborated, based on clinical, neuropsychological, and imaging data. They define typical and atypical forms of SD. A diagnosis of typical SD relies on an isolated and progressive loss of semantic knowledge, attested by a deficit of word comprehension and a deficit of objects and/or people identification, with imaging showing temporal atrophy and/or hypometabolism. SD is atypical if the deficit of semantic knowledge is present only within a single modality (verbal versus visual), or if non-semantic deficits (mild and not present at onset) and/or neurological signs, are associated with the semantic loss.

From individual to collective dynamics in Argentine ants (Linepithema humile).

In this paper we propose a model for the formation of paths in Argentine ants when foraging in an empty arena. Based on experimental observations, we provide a distribution for the random change in direction that they approximately undergo while foraging as a mixture of a Gaussian and a Pareto distribution. By following the principles described in previous work, we consider persistence and reinforcement to create a model for the motion of ants in the plane. Numerical simulations based on this model lead to the formation of branched ant-trails analogous to those observed experimentally.

Is practice rate rather than exercise intensity more important in health benefits of moderately obese postmenopausal women?

OBJECTIVE: The aim of this study was to evaluate the impact of brisk walking on physical fitness, body composition and fasting lipid-lipoprotein profile of women 50-65 years-old, once adherence or exercise intensity is considered. METHODS: A sample of 159 healthy, sedentary, obese postmenopausal women (body mass index [BMI]=29-35 kg/m2) was subjected to 3 sessions/week of 45 min-walking, at 60% of heart rate reserve (HRR), during 16 weeks. Body composition, physical fitness and fasting lipid-lipoprotein profile were assessed before and after the intervention. RESULTS: Among the three tertiles of adherence to exercise sessions (<71%, 71-87%,>87%) women displaying the greatest one were characterized by the highest reduction in body weight (-1.9±2.7 kg) (mean±SD), fat mass (-2.0±2.3 kg) and waist girth (-4.4±3.4 cm) and the best improvement in physical fitness (7.3±3.5 mL O2/kg/min), (P<0.0001). A comparable analysis based on tertiles of walking intensity (<56%, 56-63%,>63% HRR) did not show between-group differences in body composition or physical fitness. Also, the fasting lipid-lipoprotein profile was improved by a reduction of cholesterol, LDL cholesterol, and triglyceride levels and by an increase in HDL cholesterol, irrespective of the participants' adherence (0.05

Auditory efferents involved in speech-in-noise intelligibility.

Following studies proposing that medial olivocochlear efferents might be involved in the processing of complex signals in noise, we tested the involvement of efferent feedback in speech-in-noise intelligibility. Two approaches were used: measures of speech-in-noise intelligibility in vestibular neurotomized patients with cut efferents and comparison with normal hearing subjects; and correlations between effectiveness of olivocochlear feedback, assessed by contralateral suppression of otoacoustic emissions and speech-in-noise intelligibility in normal subjects. Contralateral noise improved speech-in-noise intelligibility in normal ears. This improvement, which was almost absent in de-efferented ears of vestibular neurotomized patients, was correlated with the strength of the olivocochlear feedback. Together, these results suggest that olivocochlear efferents play an antimasking role in speech perception in noisy environments.

Medial olivocochlear bundle activation and perceived auditory intensity in humans.

In order to test the hypothesis of a role of cochlear efferent activity in intensity perception in humans, loudness functions, loudness integration, and loudness summation were measured in the absence and in the presence of contralateral noise in normal-hearing subjects. Additionally, relationships with the effect of the noise on evoked otoacoustic emissions (EOAEs) were tested, and comparisons with vestibular neurotomy patients were performed. Overall, the results failed to demonstrate significant effects of contralateral noise stimulation on loudness functions and loudness integration. Furthermore, no significant differences were found in vestibular neurotomy patients. A significant effect of contralateral noise on loudness summation was noted, but was not related to the effect on otoacoustic emissions. The present results fail to support the notion that efferent influences onto the cochlear compression have a significant perceptual effect.

Mean field annealing: a formalism for constructing GNC-like algorithms.

Optimization problems are approached using mean field annealing (MFA), which is a deterministic approximation, using mean field theory and based on Peierls's inequality, to simulated annealing. The MFA mathematics are applied to three different objective function examples. In each case, MFA produces a minimization algorithm that is a type of graduated nonconvexity. When applied to the ;weak-membrane' objective, MFA results in an algorithm qualitatively identical to the published GNC algorithm. One of the examples, MFA applied to a piecewise-constant objective function, is then compared experimentally with the corresponding GNC weak-membrane algorithm. The mathematics of MFA are shown to provide a powerful and general tool for deriving optimization algorithms.

Temporal loudness integration and spectral loudness summation in normal-hearing and hearing-impaired listeners.

The aim of this study was to test for differences between normal-hearing and hearing-impaired listeners regarding two fundamental aspects of intensity perception: loudness integration and loudness summation. Loudness functions for three different stimuli were measured using categorical loudness scaling in 8 normal-hearing and 12 hearing-impaired subjects. The results indicated that temporal loudness integration, defined as the difference in SPL between 16.25-ms and 300-ms noise bursts of equal loudness, was larger in the hearing-impaired than in the normal-hearing listeners. Loudness summation, defined as the difference in SPL between a 300-ms, 1,600-Hz tone pip and a white noise burst of the same duration and loudness, did not differ between the two groups. Implications of these results for hearing aid fitting strategies based on loudness normalization are discussed.