Probiotic interventions promote metabolic health in high fat-fed hamsters in association with gut microbiota and endocannabinoidome alterations

Probiotics represent a promising tool to improve metabolic health, including lipid profiles and cholesterol levels. Modulation of the gut microbiome and the endocannabinoidome - two interrelated systems involved in several metabolic processes influenced by probiotics - has been proposed as a potential mechanism of action. This study establishes the impact of probiotics on metabolic health, gut microbiota composition and endocannabinoidome mediators in an animal model of hypercholesterolaemia. Syrian hamsters were fed either a low-fat low-cholesterol or high-fat high-cholesterol (HFHC) diet to induce hypercholesterolaemia and gavaged for 6 weeks with either Lactobacillus acidophilus CL1285, Lactiplantibacillus plantarum CHOL-200 or a combination of the two. Globally, probiotic interventions ameliorated, at least partially, lipid metabolism in HFHC-fed hamsters. The interventions, especially those including L. acidophilus, modified the gut microbiota composition of the small intestine and caecum in ways suggesting reversal of HFHC-induced dysbiosis. Several associations were observed between changes in gut microbiota composition and endocannabinoidome mediators following probiotic interventions and both systems were also associated with improved metabolic health parameters. For instance, potential connexions between the Eubacteriaceae and Deferribacteraceae families, levels of 2‑palmitoylglycerol, 2‑oleoylglycerol, 2‑linoleoylglycerol or 2‑eicosapentaenoylglycerol and improved lipid profiles were found. Altogether, our results suggest a potential crosstalk between gut microbiota and the endocannabinoidome in driving metabolic benefits associated with probiotics, especially those including L. acidophilus, in an animal model of hypercholesterolaemia.

Lung pathology of natural Babesia rossi infection in dogs

A proportion of Babesia rossi infections in dogs are classified as complicated and one of the most lethal complications is acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). Most dogs that die succumb within 24 hours of presentation. The pulmonary pathology caused by B. rossi in dogs has not been described. The aim of this study was to provide a thorough macroscopic, histological and immunohistochemical description of the lung changes seen in dogs naturally infected with B. rossi that succumbed to the infection. Death was invariably accompanied by alveolar oedema. Histopathology showed acute interstitial pneumonia characterised by alveolar oedema and haemorrhages, with increased numbers of mononuclear leucocytes in alveolar walls and lumens. Intra-alveolar polymerised fibrin aggregates were observed in just over half the infected cases. Immunohistochemistry showed increased numbers of MAC387- and CD204-reactive monocyte-macrophages in alveolar walls and lumens, and increased CD3-reactive T-lymphocytes in alveolar walls, compared with controls. These histological features overlap to some extent (but far from perfectly) with the histological pattern of lung injury referred to as the exudative stage of diffuse alveolar damage (DAD) as is quite commonly reported in ALI/ARDS.

Dexamethasone and persistent wound pain: a prespecified analysis of the randomised Perioperative Administration of Dexamethasone and Infection (PADDI) trial

BACKGROUND

Dexamethasone is commonly administered intraoperatively to prevent postoperative nausea and vomiting and is believed to have analgesic properties. It is unknown whether it has an impact on chronic wound pain.

METHODS

In this prespecified embedded superiority substudy of the randomised PADDI trial, patients undergoing non-urgent noncardiac surgery received dexamethasone 8 mg or placebo intravenously after induction of anaesthesia, and were followed up for 6 months postoperatively. The primary outcome was the incidence of pain in the surgical wound at 6 months. Secondary outcomes included acute postoperative pain and correlates of chronic postsurgical pain.

RESULTS

We included 8478 participants in the modified intention-to-treat population (4258 in the dexamethasone group and 4220 in the matched placebo group). The primary outcome occurred in 491 subjects (11.5%) in the dexamethasone arm and 404 (9.6%) subjects in the placebo arm (relative risk 1.2, 95% confidence interval 1.06-1.41, P=0.003). Maximum pain scores at rest and on movement in the first 3 postoperative days were lower in the dexamethasone group compared with the control group {median 5 (inter-quartile range [IQR] 3.0-8.0) vs 6 (IQR 3.0-8.0) and median 7 (IQR 5.0-9.0) vs 8 (IQR 6.0-9.0), P<0.001 for both}. Severity of postoperative pain was not predictive of chronic postsurgical pain. The severity of chronic postsurgical pain and the frequency of neuropathic features did not differ between treatment groups.

CONCLUSION

Administration of dexamethasone 8 mg i.v. was associated with an increase in the risk of pain in the surgical wound 6 months after surgery.

CLINICAL TRIAL REGISTRATION

ACTRN12614001226695.

On-farm evaluation of multiparametric models to predict subacute ruminal acidosis in dairy cows

This research aimed: (i) to evaluate on-farm (FARM data) multiparametric models developed under controlled experiment (INRAE data) and based on non-invasive indicators to detect subacute ruminal acidosis (SARA) in dairy cows. We also aimed to recover high discrimination capacity, if needed, by (ii) building new models with combined INRAE and FARM data; and (iii) enriching the models increasing from 2 to 5 indicators per model. For model enrichment, we focused on indicators determinable on-farm by quick and inexpensive routine analysis. Fifteen commercial dairy farms were selected to cover a wide range of SARA risk. In each farm, four Holstein early-lactating healthy primiparous cows were selected based on their last on-farm recording of milk yield and somatic cell count analysis. Cows were equipped with a reticulo-rumen pH sensor. The pH kinetics were analysed over a subsequent 7-day period. Relative pH indicators were used to classify cows with or without SARA. Milk, blood, faeces, and urine were collected for analysis of the indicators included in the models developed by Villot et al. (2020) on INRAE data that were externally evaluated using FARM data. Then, new models based on the same indicators were developed combining INRAE and FARM data to test whether a possible loss in performance was due to a limited validity domain of model by Villot et al (2020). Finally, the models developed combining INRAE and FARM data were adapted to the on-farm application and enriched by increasing indicators from 2 to 5 per model using linear discriminant analysis and leave-one-out cross-validation. The sensitivities (true-positive rate) in external evaluation on FARM data were substantially lower than those from cross-validation by Villot et al. (2020) (range: 0.1-0.75 vs 0.79-0.96, respectively), and the specificities (true-negative rate) showed a larger range with lower minimum values (range: 0.18-1.0 vs 0.62-0.97, respectively). The sensitivities of new models developed combining INRAE and FARM data ranged from 0.63 to 0.77. Models involving blood cholesterol, β-hydroxybutyrate, haptoglobin, milk and blood urea, and models involving milk fat/protein ratio, dietary starch proportion, and milk fatty acids had the highest performances, whereas models including sieved faecal residues and urine pH had the lowest. Enriching models to three indicators per model improved sensitivity and specificity, but the inclusion of more indicators was less or not effective. Larger field trials are required to validate our results and to increase variability and validity domain of models.

Changes in circulating forms of anti-Muüllerian hormone and androgens in women with and without PCOS: a systematic longitudinal study throughout pregnancy

STUDY QUESTION

What are the changes in serum concentration of total and cleaved anti-Muüllerian hormone (AMH) molecular forms and of androgens before and throughout pregnancy in women with and without polycystic ovary syndrome (PCOS) in a longitudinal follow-up investigation?

SUMMARY ANSWER

Serum levels of total and cleaved AMH are higher from preconception to the third trimester of pregnancy in women with PCOS as compared to controls, whereas testosterone and androstenedione levels are higher in women with PCOS than in control women before pregnancy and during the second and third trimester of pregnancy.

WHAT IS KNOWN ALREADY

Cross-sectional or partial longitudinal studies have shown higher AMH and androgen levels in pregnant women with PCOS as compared with non-PCOS women. To date, no complete longitudinal dynamic monitoring of the circulating forms of AMH and androgens from pre-conception to the third trimester of pregnancy have compared women with and without PCOS.

STUDY DESIGN, SIZE, DURATION

This systematic prospective quarterly longitudinal monocentric study was a comparative follow-up of 30 women with PCOS and 29 controls before and during pregnancy from April 2019 to July 2022.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Women aged 18-43 years with a pre-conception measurement of AMH were included during the first trimester of a singleton pregnancy. The PCOS group was defined according to the Rotterdam diagnostic criteria. The control group patients included in the study had normal ovarian reserves. Circulating total and cleaved AMH, and serum estradiol, LH, and androgen levels were measured during the first, second, and third trimester of pregnancy in all study participants.

MAIN RESULTS AND THE ROLE OF CHANCE

Before pregnancy, patients with PCOS had higher levels of AMH than controls. The total and cleaved AMH forms were significantly higher in women with PCOS than controls from pre-conception to the third trimester of pregnancy (all P < 0.001). Androgens (total testosterone and androstenedione) were higher in women with PCOS than controls from mid-pregnancy onwards.

LIMITATIONS, REASONS FOR CAUTION

Our control population was a population of infertile women with no ovarian problems but most of them had undergone ART treatments to achieve pregnancy.

WIDER IMPLICATIONS OF THE FINDINGS

These results strengthen the hypothesis that gestational hyperandrogenism as well as exposure to elevated AMH levels in utero could be driving forces predisposing female progeny to develop PCOS.

STUDY FUNDING/COMPETING INTEREST(S)

Funding was provided by INSERM, France (grant number U1172) and the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program, ERC-2016-CoG to P.G. grant agreement n° 725149/REPRODAMH. The authors have nothing to declare.

TRIAL REGISTRATION NUMBER

NCT03483792.

[Constrictive pericarditis and disseminated nocardiosis]

Human nocardiosis usually involves the respiratory tract or the skin but may disseminate to virtually any organ, it occurs in immunocompromised hosts as well as individuals with no apparent predisposition. Involvement of the pericardium is uncommon, having been reported infrequently in the past, but mandates a special management. This report describes the first case in Europe of a patient with chronic constrictive pericarditis from nocardia brasiliens, successfully treated with pericardiectomy and appropriate antibiotic therapy.

Pneumonia-associated Emergency Transfers, Functional Decline, and Mortality in Nursing Home Residents

OBJECTIVE

To describe nursing home residents (NHRs) transferred to the emergency department (ED) with pneumonia, and investigate the association of pneumonia with functional ability and mortality.

DESIGN

Case-control observational multicenter study.

SETTING AND PARTICIPANTS

Participants of the FINE study, including 1037 NHRs presenting to 17 EDs in France over 4 nonconsecutive weeks (1 per season) in 2016, mean age 87.2 years ± 7.1, 68.4% women.

METHODS

Activities of daily living (ADL) performance evolution between (1) 15 days before transfer and (2) within 7 days after discharge back to the nursing home was compared in NHRs with or without pneumonia. The association of pneumonia with functional evolution was investigated by a mixed-effect linear regression of ADL and mortality was compared by a χ² test.

RESULTS

NHRs with pneumonia (n = 232; 22.4%) were more likely to have a lower ADL performance than NHRs without pneumonia (n = 805, 77.6%). They presented with a more severe clinical condition, were more likely to be hospitalized after ED and to stay longer in ED and in hospital. They showed a 0.5 decline in median ADL performance after transfer and a significantly higher mortality than NHRs without pneumonia (24.1% and 8.7%, respectively). Post-ED functional evolution did not differ significantly between NHRs with or without pneumonia.

CONCLUSIONS AND IMPLICATIONS

Pneumonia-associated ED transfers resulted in longer care pathways and higher mortality, but no significant difference in functional decline. This study identified a suggestive course of symptoms that could facilitate early identification of NHRs developing pneumonia and early management to prevent ED transfer.

The atmospheric X-ray imaging spectrometer (AXIS) instrument: Quantifying energetic particle precipitation through bremsstrahlung X-ray imaging

The Atmospheric X-ray Imaging Spectrometer (AXIS) described in this work is a compact, wide field-of-view, hard x-ray imager. The AXIS instrument will fly onboard the Atmospheric Effects of Precipitation through Energetic X-rays (AEPEX) 6U CubeSat mission and will measure bremsstrahlung x-ray photons in the 50-240 keV range with cadmium-zinc-telluride (CZT) detectors using coded aperture optics. AXIS will measure photons generated by energetic particle precipitation for the purpose of determining the spatial scales of precipitation and estimating electron precipitation characteristics. This paper describes the design and testing of the AXIS instrument, including a summary of simulations performed that motivate the shielding, optics, and mechanical design. Testing and characterization is reported that validates the instrument design and shows that the instrument design meets or exceeds the measurement requirements necessary for AEPEX mission success.

COVID-19 infection and maternal morbidity in critical care units in Scotland: a national cohort study

BACKGROUND

Previous research has shown that, in comparison with non-pregnant women of reproductive age, pregnant women with COVID-19 are more likely to be admitted to critical care, receive invasive ventilation, and die. At present there are limited data in relation to outcomes and healthcare utilisation following hospital discharge of pregnant and recently pregnant women admitted to critical care.

METHODS

A national cohort study of pregnant and recently pregnant women who were admitted to critical care in Scotland with confirmed or suspected COVID-19. We examined hospital outcomes as well as hospital re-admission rates.

RESULTS

Between March 2020 and March 2022, 75 pregnant or recently pregnant women with laboratory-confirmed COVID-19 were admitted to 24 Intensive Care Units across Scotland. Almost two thirds (n=49, 65%) were from the most deprived socio-economic areas. Complete 90-day acute hospital re-admission data were available for 74 (99%) patients. Nine (12%) women required an emergency non-obstetric hospital re-admission within 90 days. Less than 5% of the cohort had received any form of vaccination.

CONCLUSIONS

This national cohort study has demonstrated that pregnant or recently pregnant women admitted to critical care with COVID-19 were more likely to reside in areas of socio-economic deprivation, and fewer than 5% of the cohort had received any form of vaccination. More targeted public health campaigning across the socio-economic gradient is urgently required.

Introduction and integration of PrEP and sexual and reproductive health services for young people: Health provider perspectives from South Africa

South Africa has one of the largest HIV epidemics in the world, with particularly high prevalence among adolescent girls and young women (AGYW). Oral PrEP was introduced in the public sector in 2016 in a phased manner. Given the important role played by health providers, research was undertaken to understand their experiences of and attitudes towards introduction of PrEP as a new HIV prevention method, and its integration within broader sexual and reproductive health (SRH) services for youth. A survey was undertaken with 48 purposively sampled health providers working in primary health care facilities and mobile clinics in three provinces in South Africa. Qualitative analysis was performed on free-text responses to open-ended questions in the survey, using an inductive approach to code the data in NVivo v.12 software. Health providers expressed concerns about adding a new service to an already overburdened health system, and worried that young people seeking PrEP would divert staff from other critical services. While most recognised the benefits and opportunities afforded by HIV and SRH service integration, providers highlighted the extra time and resources such integration would require. Many were anxious that PrEP would encourage disinhibition and increase unprotected sex among AGYW, and held judgemental attitudes about young people, seen as largely incapable of taking responsibility for their health. Findings underscore the importance of consulting health providers about implementation design and providing channels for them to express their misgivings and concerns, and training needs to be designed to address provider attitudes and values. Opportunities need to be sought to strengthen the provision of adolescent and youth friendly services-including adolescent-health provider dialogues. Insights from this study can assist in guiding the introduction of new HIV prevention methods into the future.

Frequency of Diarrhea, Stool Specimen Collection and Testing, and Detection of Clostridioides Difficile Infection Among Hospitalized Adults in the Muenster/Coesfeld Area, Germany

Clostridioides difficile infection (CDI) often manifests as diarrhea, particularly in adults of older age or with underlying comorbidities. However, only severe cases are notifiable in Germany. Moreover, failure to collect a stool specimen from inpatients with diarrhea or incomplete testing may lead to underdiagnosis and underreporting of CDI. We assessed the frequency of diarrhea, stool specimen collection, and CDI testing to estimate CDI underdiagnosis and underreporting among hospitalized adults. In a ten-day point-prevalence study (2019-2021) of nine hospitals in a defined area (Muenster/Coesfeld, North Rhine-Westphalia, Germany), all diarrhea cases (≥ 3 loose stools in 24 h) among adult inpatients were captured via medical record screening and nurse interviews. Patient characteristics, symptom onset, putative origin, antibiotic consumption, and diagnostic stool sampling were collected in a case report form (CRF). Diagnostic results were retrieved from the respective hospital laboratories. Among 6998 patients screened, 476 (7%) diarrhea patients were identified, yielding a hospital-based incidence of 201 cases per 10,000 patient-days. Of the diarrheal patients, 186 (39%) had a stool sample collected, of which 160 (86%) were tested for CDI, meaning that the overall CDI testing rate among diarrhea patients was 34%. Toxigenic C. difficile was detected in 18 (11%) of the tested samples. The frequency of stool specimen collection and CDI testing among hospitalized diarrhea patients was suboptimal. Thus, CDI incidence in Germany is likely underestimated. To assess the complete burden of CDI in German hospitals, further investigations are needed.

Effect of Lower vs Higher Oxygen Saturation Targets on Survival to Hospital Discharge Among Patients Resuscitated After Out-of-Hospital Cardiac Arrest: The EXACT Randomized Clinical Trial

IMPORTANCE

The administration of a high fraction of oxygen following return of spontaneous circulation in out-of-hospital cardiac arrest may increase reperfusion brain injury.

OBJECTIVE

To determine whether targeting a lower oxygen saturation in the early phase of postresuscitation care for out-of-hospital cardiac arrest improves survival at hospital discharge.

DESIGN, SETTING, AND PARTICIPANTS

This multicenter, parallel-group, randomized clinical trial included unconscious adults with return of spontaneous circulation and a peripheral oxygen saturation (Spo2) of at least 95% while receiving 100% oxygen. The trial was conducted in 2 emergency medical services and 15 hospitals in Victoria and South Australia, Australia, between December 11, 2017, and August 11, 2020, with data collection from ambulance and hospital medical records (final follow-up date, August 25, 2021). The trial enrolled 428 of a planned 1416 patients.

INTERVENTIONS

Patients were randomized by paramedics to receive oxygen titration to achieve an oxygen saturation of either 90% to 94% (intervention; n = 216) or 98% to 100% (standard care; n = 212) until arrival in the intensive care unit.

MAIN OUTCOMES AND MEASURES

The primary outcome was survival to hospital discharge. There were 9 secondary outcomes collected, including hypoxic episodes (Spo2 &lt;90%) and prespecified serious adverse events, which included hypoxia with rearrest.

RESULTS

The trial was stopped early due to the COVID-19 pandemic. Of the 428 patients who were randomized, 425 were included in the primary analysis (median age, 65.5 years; 100 [23.5%] women) and all completed the trial. Overall, 82 of 214 patients (38.3%) in the intervention group survived to hospital discharge compared with 101 of 211 (47.9%) in the standard care group (difference, -9.6% [95% CI, -18.9% to -0.2%]; unadjusted odds ratio, 0.68 [95% CI, 0.46-1.00]; P = .05). Of the 9 prespecified secondary outcomes collected during hospital stay, 8 showed no significant difference. A hypoxic episode prior to intensive care was observed in 31.3% (n = 67) of participants in the intervention group and 16.1% (n = 34) in the standard care group (difference, 15.2% [95% CI, 7.2%-23.1%]; OR, 2.37 [95% CI, 1.49-3.79]; P &lt; .001).

CONCLUSIONS AND RELEVANCE

Among patients achieving return of spontaneous circulation after out-of-hospital cardiac arrest, targeting an oxygen saturation of 90% to 94%, compared with 98% to 100%, until admission to the intensive care unit did not significantly improve survival to hospital discharge. Although the trial is limited by early termination due to the COVID-19 pandemic, the findings do not support use of an oxygen saturation target of 90% to 94% in the out-of-hospital setting after resuscitation from cardiac arrest.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03138005.

Trajectory and Predictors of Mental Health Symptoms and Wellbeing in Newly Admitted Nursing Home Residents

OBJECTIVES

This study determined changes in multiple aspects of mental health and wellbeing in newly admitted nursing home residents, and identified risk and protective factors.

METHODS

Participants were 204 residents recently admitted to one of 42 nursing homes in Melbourne, Australia. A subgroup of 82 participants were followed up eight months post-admission. Depression, anxiety, stress, adjustment, and quality of life were assessed at baseline and follow-up. Predictive factors (demographics, health, transition factors, nursing home characteristics) were examined in multiple regression analyses.

RESULTS

Rates of depression and anxiety were high at both baseline and follow-up. Low self-rated health and medical comorbidity predicted poor wellbeing at baseline. Higher perceived control in the relocation to the nursing home and engagement in meaningful activities were associated with better post-admission outcomes. Baseline psychotropic medication use predicted lower anxiety at follow-up but did not impact depressive symptoms.

CONCLUSIONS

There were no significant changes in mental health and wellbeing from one to eight months post-admission. The negative effect of residing in a for-profit nursing home requires further investigation.

CLINICAL IMPLICATIONS

Individual activity scheduling and an opportunity to participate in relocation decision-making and planning may support resident wellbeing post-admission.

Methodological guidelines: Cow milk mid-infrared spectra to predict GreenFeed enteric methane emissions

Various methodological protocols were tested on milk samples from cows fed diets affecting both methanogenesis and milk synthesis to identify the best approach for the prediction of GreenFeed system (GF) measured methane (CH₄) emissions by milk mid-infrared (MIR) spectroscopy. The models developed were also tested on a data set from cows fed chemical inhibitors of CH₄ emission [3-nitrooxypropanol (3NOP)] that just marginally affect milk composition. A total of 129 primiparous and multiparous Holstein cows fed diets with different methanogenic potential were considered. Individual milk yield (MY) and dry matter intake were recorded daily, whereas fat- and protein-corrected milk (FPCM) was recorded twice a week. The MIR spectra from 2 consecutive milkings were collected twice a week. Twenty CH₄ spot measurements with GF were taken as the basic measurement unit (BMU) of CH₄. The equations were built using partial least squares regression by splitting the database into calibration and validation data sets (excluding 3NOP samples). Models were developed for milk MIR spectra by milking and on day spectra obtained by averaging spectra from 2 consecutive milkings. Models based on day spectra were calibrated by using CH₄ reference data for a measurement duration of 1, 2, 3, or 4 BMU. Models built from the average of the day spectra collected during the corresponding CH₄ measurement periods were developed. Corrections of spectra by days in milk (DIM) and the inclusion of parity, MY, and FPCM as explanatory variables were tested as tools to improve model performance. Models built on day milk MIR spectra gave slightly better performances that those developed using spectra from a single milking. Long duration of CH₄ measurement by GF performed better than short duration: the coefficient of determination of validation (R²V) for CH₄ emissions expressed in grams per day were 0.60 vs. 0.52 for 4 and 1 BMU, respectively. When CH₄ emissions were expressed as grams per kilogram of dry of matter intake, grams per kilogram of MY, or grams per kilogram of FPCM, performance with a long duration also improved. Coupling GF reference data with the average of milk MIR spectra collected throughout the corresponding CH₄ measurement period gave better predictions than using day spectra (R²V = 0.70 vs. 0.60 for CH₄ as g/d on 4 BMU). Correcting the day spectra by DIM improved R²V compared with the equivalent DIM-uncorrected models (R²V = 0.67 vs. 0.60 for CH₄ as g/d on 4 BMU). Adding other phenotypic information as explanatory variables did not further improve the performance of models built on single day DIM-corrected spectra, whereas including MY (or FPCM) improved the performance of models built on the average of spectra (uncorrected by DIM) recorded during the CH₄ measurement period (R²V = 0.73 vs. 0.70 for CH₄ as g/d on 4 BMU). When validating the models on the 3NOP data set, predictions were poor without (R²V = 0.13 for CH₄ as g/d on 1 BMU) or with (R²V = 0.31 for CH₄ as g/d on 1 BMU) integration of 3NOP data in the models. Thus, specific models would be required for CH₄ prediction when cows receive chemical inhibitors of CH₄ emissions not affecting milk composition.

Use of explicit priming to phenotype absolute pitch ability

Musicians with absolute pitch (AP) can name the pitch of a musical note in isolation. Expression of this unusual ability is thought to be influenced by heritability, early music training and current practice. However, our understanding of factors shaping its expression is hampered by testing and scoring methods that treat AP as dichotomous. These fail to capture the observed variability in pitch-naming accuracy among reported AP possessors. The aim of this study was to trial a novel explicit priming paradigm to explore phenotypic variability of AP. Thirty-five musically experienced individuals (M_age = 29 years, range 18–68; 14 males) with varying AP ability completed a standard AP task and the explicit priming AP task. Results showed: 1) phenotypic variability of AP ability, including high-accuracy AP, heterogeneous intermediate performers, and chance-level performers; 2) intermediate performance profiles that were either reliant on or independent of relative pitch strategies, as identified by the priming task; and 3) the emergence of a bimodal distribution of AP performance when adopting scoring criteria that assign credit to semitone errors. These findings show the importance of methods in studying behavioural traits, and are a key step towards identifying AP phenotypes. Replication of our results in larger samples will further establish the usefulness of this priming paradigm in AP research.