An International, Expert-Based Delphi Consensus Document on Controversial Issues about TransCarotid Artery Revascularization (TCAR).

OBJECTIVE: TransCarotid Artery Revascularization (TCAR) has emerged as an alternative therapeutic modality to carotid endarterectomy (CEA) and transfemoral carotid artery stenting (TFCAS) for the management of patients with carotid artery stenosis. However, certain issues regarding the indications and contraindications of TCAR remain unanswered or unresolved. The aim of this international, expert-based Delphi Consensus document was to attempt to provide some guidance on these topics. METHODS: A 3-Round Delphi Consensus process was performed including 29 experts. The aim of Round 1 was to investigate the differing views and opinions of the participants. Round 2 was carried out after the results from the literature on each topic were provided to the participants. During Round 3, the participants had the opportunity to finalize their vote. RESULTS: Most participants agreed that TCAR can/can probably/possibly be performed within 14 days of a cerebrovascular event, but it is best to avoid it in the first 48 hours. It was felt that TCAR cannot/should not replace TFCAS or CEA, as each procedure has specific indications and contraindications. Symptomatic patients >80 years should probably be treated with TCAR rather than with TFCAS. TCAR can/can probably be used for the treatment of restenosis following CEA/TFCAS. Finally, there is a need for a randomized controlled trial to provide better evidence for the unresolved issues. CONCLUSIONS: This Delphi Consensus document attempted to assist the decision-making of physicians/interventionalists/vascular surgeons involved in the management of carotid stenosis patients. Furthermore, areas requiring additional research were identified. Future studies and randomized controlled trials should provide more evidence to address the unanswered questions regarding TCAR.

Comprehensive body fluid identification and contributor assignment by combining targeted sequencing of mRNA and coding region SNPs.

Forensic genetic analyses aim to retrieve as much information as possible from biological trace material recovered from crime scenes. While standard short tandem repeat (STR) profiling is essential to individualize biological traces, its significance is diminished in crime scenarios where the presence of a suspect's DNA is acknowledged by all parties. In such cases, forensic (m)RNA analysis can provide crucial contextualizing information on the source level about a trace's composition, i.e., body fluids/tissues, and has therefore emerged as a powerful tool for modern forensic investigations. However, the question which of several suspects contributed a specific component (body fluid) to a mixed trace cannot be answered by RNA analysis using conventional methods. This individualizing information is stored within the sequence of the mRNA transcripts. Massively parallel sequencing (MPS) represents a promising alternative, offering not only higher multiplex capacity, but also the typing of individual coding region SNPs (cSNPs) to enable the assignment of contributors to mixture components, thereby reducing the risk of association fallacies. Herein, we describe the development of an extensive mRNA/cSNP panel for targeted sequencing on the IonTorrent S5 platform. Our panel comprises 30 markers for the detection of six body fluids/tissues (blood, saliva, semen, skin, vaginal and menstrual secretion), along with 70 linkage-controlled cSNPs for contributor assignment. It exhibited high reliable detection sensitivity with RNA inputs down to 0.75 ng and a conservatively calculated probability of identity of 0.03 - 6 % for individual body fluid-specific cSNP profiles. Limitations and areas for future work include RNA-related allele imbalances, inclusion of markers to correctly identify rectal mucosa and the optimization of specific markers. In summary, our new panel is intended to be a major step forward to interpret biological evidence at sub-source and source level based on cSNP attribution of a body fluid component to a suspect and victim, respectively.

Recommendations of the DNA Commission of the International Society for Forensic Genetics (ISFG) on short tandem repeat sequence nomenclature.

The DNA Commission of the International Society for Forensic Genetics (ISFG) has developed a set of nomenclature recommendations for short tandem repeat (STR) sequences. These recommendations follow the 2016 considerations of the DNA Commission of the ISFG, incorporating the knowledge gained through research and population studies in the intervening years. While maintaining a focus on backward compatibility with the CE data that currently populate national DNA databases, this report also looks to the future with the establishment of recommended minimum sequence reporting ranges to facilitate interlaboratory comparisons, automated solutions for sequence-based allele designations, a suite of resources to support bioinformatic development, guidance for characterizing new STR loci, and considerations for incorporating STR sequences and other new markers into investigative databases.

The impact of revascularization strategy on clinical failure, hemodynamic failure, and chronic limb-threatening ischemia symptoms in the BEST-CLI Trial.

OBJECTIVE: Sustained clinical and hemodynamic benefit after revascularization for chronic limb-threatening ischemia (CLTI) is needed to resolve symptoms and prevent limb loss. We sought to compare rates of clinical and hemodynamic failure as well as resolution of initial and prevention of recurrent CLTI after endovascular (ENDO) vs bypass (OPEN) revascularization in the Best-Endovascular-versus-best-Surgical-Therapy-in-patients-with-CLTI (BEST-CLI) trial. METHODS: As planned secondary analyses of the BEST-CLI trial, we examined the rates of (1) clinical failure (a composite of all-cause death, above-ankle amputation, major reintervention, and degradation of WIfI stage); (2) hemodynamic failure (a composite of above-ankle amputation, major and minor reintervention to maintain index limb patency, failure to an initial increase or a subsequent decrease in ankle brachial index of 0.15 or toe brachial index of 0.10, and radiographic evidence of treatment stenosis or occlusion); (3) time to resolution of presenting CLTI symptoms; and (4) incidence of recurrent CLTI. Time-to-event analyses were performed by intention-to-treat assignment in both trial cohorts (cohort 1: suitable single segment great saphenous vein [SSGSV], N = 1434; cohort 2: lacking suitable SSGSV, N = 396), and multivariate stratified Cox regression models were created. RESULTS: In cohort 1, there was a significant difference in time to clinical failure (log-rank P < .001), hemodynamic failure (log-rank P < .001), and resolution of presenting symptoms (log-rank P = .009) in favor of OPEN. In cohort 2, there was a significantly lower rate of hemodynamic failure (log-rank P = .006) favoring OPEN, and no significant difference in time to clinical failure or resolution of presenting symptoms. Multivariate analysis revealed that assignment to OPEN was associated with a significantly lower risk of clinical and hemodynamic failure in both cohorts and a significantly higher likelihood of resolving initial and preventing recurrent CLTI symptoms in cohort 1, including after adjustment for key baseline patient covariates (end-stage renal disease [ESRD], prior revascularization, smoking, diabetes, age >80 years, WIfI stage, tissue loss, and infrapopliteal disease). Factors independently associated with clinical failure included age >80 years in cohort 1 and ESRD across both cohorts. ESRD was associated with hemodynamic failure in cohort 1. Factors associated with slower resolution of presenting symptoms included diabetes in cohort 1 and WIfI stage in cohort 2. CONCLUSIONS: Durable clinical and hemodynamic benefit after revascularization for CLTI is important to avoid persistent and recurrent CLTI, reinterventions, and limb loss. When compared with ENDO, initial treatment with OPEN surgical bypass, particularly with available saphenous vein, is associated with improved clinical and hemodynamic outcomes and enhanced resolution of CLTI symptoms.

Influence of Alkali Metal Cations on the Oxygen Reduction Activity of Pt5Y and Pt5Gd Alloys.

Electrolyte species can significantly influence the electrocatalytic performance. In this work, we investigate the impact of alkali metal cations on the oxygen reduction reaction (ORR) on active Pt5Gd and Pt5Y polycrystalline electrodes. Due to the strain effects, Pt alloys exhibit a higher kinetic current density of ORR than pure Pt electrodes in acidic media. In alkaline solutions, the kinetic current density of ORR for Pt alloys decreases linearly with the decreasing hydration energy in the order of Li+ > Na+ > K+ > Rb+ > Cs+, whereas Pt shows the opposite trend. To gain further insights into these experimental results, we conduct complementary density functional theory calculations considering the effects of both electrode surface strain and electrolyte chemistry. The computational results reveal that the different trends in the ORR activity in alkaline media can be explained by the change in the adsorption energy of reaction intermediates with applied surface strain in the presence of alkali metal cations. Our findings provide important insights into the effects of the electrolyte and the strain conditions on the electrocatalytic performance and thus offer valuable guidelines for optimizing Pt-based electrocatalysts.

Collaborative exercise: analysis of age estimation using a QIAGEN protocol and the PyroMark Q48 platform.

Human age estimation from trace samples may give important leads early in a police investigation by contributing to the description of the perpetrator. Several molecular biomarkers are available for the estimation of chronological age, and currently, DNA methylation patterns are the most promising. In this study, a QIAGEN age protocol for age estimation was tested by five forensic genetic laboratories. The assay comprised bisulfite treatment of the extracted DNA, amplification of five CpG loci (in the genes of ELOVL2, C1orf132, TRIM59, KLF14, and FHL2), and sequencing of the amplicons using the PyroMark Q48 platform. Blood samples from 49 individuals with ages ranging from 18 to 64 years as well as negative and methylation controls were analyzed. An existing age estimation model was applied to display a mean absolute deviation of 3.62 years within the reference data set. Key points: Age determination as an intelligence tool during investigations can be a powerful tool in forensic genetics.In this study, five laboratories ran 49 samples and obtained a mean absolute deviation of 3.62 years.Five markers were analyzed on a PyroMark Q48 platform.

Why selective screening for asymptomatic carotid stenosis is currently appropriate: a special report.

INTRODUCTION: Two of the main reasons recent guidelines do not recommend routine population-wide screening programs for asymptomatic carotid artery stenosis (AsxCS) is that screening could lead to an increase of carotid revascularization procedures and that such mass screening programs may not be cost-effective. Nevertheless, selective screening for AsxCS could have several benefits. This article presents the rationale for such a program. AREAS COVERED: The benefits of selective screening for AsxCS include early recognition of AsxCS allowing timely initiation of preventive measures to reduce future myocardial infarction (MI), stroke, cardiac death and cardiovascular (CV) event rates. EXPERT OPINION: Mass screening programs for AsxCS are neither clinically effective nor cost-effective. Nevertheless, targeted screening of populations at high risk for AsxCS provides an opportunity to identify these individuals earlier rather than later and to initiate a number of lifestyle measures, risk factor modifications, and intensive medical therapy in order to prevent future strokes and CV events. For patients at 'higher risk of stroke' on best medical treatment, a prophylactic carotid intervention may be considered.

Relevance of BEST-CLI trial endpoints in a tertiary care limb preservation program.

OBJECTIVE: Major adverse limb event-free survival (MALE-FS) differed significantly by initial revascularization approach in the BEST-CLI randomized trial. The BEST-CLI trial represented a highly selected subgroup of patients seen in clinical practice; thus, we examined the endpoint of MALE-FS in an all-comers tertiary care practice setting. METHODS: This is a single-center retrospective study of consecutive, unique patients who underwent technically successful infrainguinal revascularization for chronic limb-threatening ischemia (2011-2021). MALE was major amputation (transtibial or above) or major reintervention (new bypass, open bypass revision, thrombectomy, or thrombolysis). RESULTS: Among 469 subjects, the mean age was 70 years, and 34% were female. Characteristics included diabetes (68%), end-stage renal disease (ESRD) (16%), Wound, Ischemia, and foot Infection (WIfI) stage 4 (44%), Global Limb Anatomic Staging System (GLASS) stage 3 (62%), and high pedal artery calcium score (pMAC) (22%). Index revascularization was autogenous vein bypass (AVB) (30%), non-autogenous bypass (NAB) (13%), or endovascular (ENDO) (57%). The composite endpoint of MALE or death occurred in 237 patients (51%) at a median time of 189 days from index revascularization. In an adjusted Cox model, factors independently associated with MALE or death included younger age, ESRD, WIfI stage 4, higher GLASS stage, and moderate-severe pMAC, whereas AVB was associated with improved MALE-FS. Freedom from MALE-FS, MALE, and major amputation at 30 days were 90%, 92%, and 95%; and at 1 year were 63%, 70%, and 83%, respectively. MALE occurred in 144 patients (31%) and was associated with ESRD, WIfI stage, GLASS stage, pMAC score, and index revascularization approach. AVB had superior durability, with adjusted 2-year freedom from MALE of 72%, compared with 66% for ENDO and 51% for NAB. Within the AVB group, spliced vein conduit had higher MALE compared with single-segment vein (hazard ratio, 1.8; 95% confidence interval, 0.9-3.7; P = .008 after inverse propensity weighting), but there was no statistically significant difference in major amputation. Of the 144 patients with any MALE, the first MALE was major reintervention in 47% and major amputation in 53%. Major amputation as first MALE was associated with non-AVB index approach. Indications for major reintervention were symptomatic stenosis/occlusion (54%), lack of clinical improvement (28%), asymptomatic graft stenosis (16%), and iatrogenic events (3%). Conversion to bypass occurred after 6% of ENDO cases, two-thirds of which involved distal bypass targets at the ankle or foot. CONCLUSIONS: In this consecutive, all-comers cohort, disease complexity was associated with procedural selection and MALE-FS. AVB independently provided the greatest MALE-FS and freedom from MALE and major amputation. Compared with the BEST-CLI randomized trial, MALE after ENDO in this series was more frequently major amputation, with relatively few conversions to open bypass.

Outcomes following carotid revascularization for stroke stratified by Modified Rankin Scale and time of intervention.

OBJECTIVES: The relationship between baseline Modified Rankin Scale (mRS) in patients with prior stroke and optimal timing of carotid revascularization is unclear. Therefore, we evaluated the timing of transfemoral carotid artery stenting (tfCAS), transcarotid artery revascularization (TCAR), and carotid endarterectomy (CEA) after prior stroke, stratified by preoperative mRS. METHODS: We identified patients with recent stroke who underwent tfCAS, TCAR, or CEA between 2012 and 2021. Patients were stratified by preoperative mRS (0-1, 2, 3-4, or 5) and days from symptom onset to intervention (time to intervention; ≤2 days, 3-14 days, 15-90 days, and 91-180 days). First, we performed univariate analyses comparing in-hospital outcomes between separate mRS or time-to-intervention cohorts for all carotid intervention methods. Afterward, multivariable logistic regression was used to adjust for demographics and comorbidities across groups, and outcomes between the various intervention methods were compared. Primary outcome was the in-hospital stroke/death rate. RESULTS: We identified 4260 patients who underwent tfCAS, 3130 patients who underwent TCAR, and 20,012 patients who underwent CEA. Patients were most likely to have minimal disability (mRS, 0-1 [61%]) and least likely to have severe disability (mRS, 5 [1.5%]). Patients most often underwent revascularization in 3 to 14 days (45%). Across all intervention methods, increasing preoperative mRS was associated with higher procedural in-hospital stroke/death (all P < .03), whereas increasing time to intervention was associated with lower stroke/death rates (all P < .01). After adjustment for demographics and comorbidities, undergoing tfCAS was associated with higher stroke/death compared with undergoing CEA (adjusted odds ratio, 1.6; 95% confidence interval, 1.3-1.9; P < .01) or undergoing TCAR (adjusted odds ratio, 1.3; 95% confidence interval, 1.0-1.8; P = .03). CONCLUSIONS: In patients with preoperative stroke, optimal timing for carotid revascularization varies with stroke severity. Increasing preoperative mRS was associated with higher procedural in-hospital stroke/death rates, whereas increasing time to-intervention was associated with lower stroke/death rates. Overall, patients undergoing CEA were associated with lower in-hospital stroke/deaths. To determine benefit for delayed intervention, these results should be weighed against the risk of recurrent stroke during the interval before intervention.

Female and male patients have similar outcomes after transcarotid artery revascularization in prospective trials.

OBJECTIVE: Sex disparities in outcomes after carotid revascularization have long been a concern, with several studies demonstrating increased postoperative death and stroke for female patients after either carotid endarterectomy or transfemoral stenting. Adverse events after transfemoral stenting are higher in female patients, particularly in symptomatic cases. Our objective was to investigate outcomes after transcarotid artery revascularization (TCAR) stratified by patient sex hypothesizing that the results would be similar between males and females. METHODS: We analyzed prospectively collected data from the Safety and Efficacy Study for Reverse Flow Used During Carotid Artery Stenting Procedure (ROADSTER)1 (pivotal), ROADSTER2 (US Food and Drug Administration indicated postmarket), and ROADSTER Extended Access TCAR trials. All patients had verified carotid stenosis meeting criteria for intervention (≥80% for asymptomatic patients and ≥50% in patient with symptomatic disease), and were included based on anatomical or clinical high-risk criteria for carotid stenting. Neurological assessments (National Institutes of Health Stroke Scale, Modified Rankin Scale) were obtained before and within 24 hours from procedure end by an independent neurologist or National Institutes of Health Stroke Scale-certified nurse. Patients were stratified by sex (male vs female). Baseline demographics were compared using χ2 and Fisher's exact tests where appropriate; primary outcomes were combination stroke/death (S/D) and S/D/myocardial infarction (S/D/M) at 30 days, and secondary outcomes were the individual components of S/D/M. Univariate logistic regression was conducted. RESULTS: We included 910 patients for analysis (306 female [33.6%], 604 male [66.4%]). Female patients were more often <65 years old (20.6% vs 15%) or ≥80 years old (22.6% vs 20.2%) compared with males, and were more often of Black/African American ethnicity (7.5% vs 4.3%). There were no differences by sex in term of comorbidities, current or prior smoking status, prior stroke, symptomatic status, or prevalence of anatomical and/or clinical high-risk criteria. General anesthetic use, stent brands used, and procedure times did not differ by sex, although flow reversal times were longer in female patients (10.9 minutes male vs 12.4 minutes female; P = .01), as was more contrast used in procedures for female patients (43 mL male vs 48.9 mL female; P = .049). The 30-day S/D and S/D/M rates were similar between male and female patients (S/D, 2.7% male vs 1.6% female [P = .34]; S/D/M, 3.6% male vs 2.6% female [P = .41]), which did not differ when stratified by symptom status. Secondary outcomes did not differ by sex, including stroke rates at 30 days (2.2% male vs 1.6% female; P = .80), nor were differences seen with stratification by symptom status. Univariate analysis demonstrated that history of a prior ipsilateral stroke was associated with increased odds of S/D (odds ratio [OR], 4.19; P = .001) and S/D/M (OR, 2.78; P = .01), as was symptomatic presentation with increased odds for S/D (OR, 2.78; P = .02). CONCLUSIONS: Prospective TCAR trial data demonstrate exceptionally low rates of S/D/MI, which do not differ by patient sex.

Recent advances and controversial issues in the optimal management of asymptomatic carotid stenosis.

OBJECTIVE: The optimal management of patients with asymptomatic carotid stenosis (AsxCS) is enduringly controversial. We updated our 2021 Expert Review and Position Statement, focusing on recent advances in the diagnosis and management of patients with AsxCS. METHODS: A systematic review of the literature was performed up to August 1, 2023, using PubMed/PubMed Central, EMBASE and Scopus. The following keywords were used in various combinations: "asymptomatic carotid stenosis," "carotid endarterectomy" (CEA), "carotid artery stenting" (CAS), and "transcarotid artery revascularization" (TCAR). Areas covered included (i) improvements in best medical treatment (BMT) for patients with AsxCS and declining stroke risk, (ii) technological advances in surgical/endovascular skills/techniques and outcomes, (iii) risk factors, clinical/imaging characteristics and risk prediction models for the identification of high-risk AsxCS patient subgroups, and (iv) the association between cognitive dysfunction and AsxCS. RESULTS: BMT is essential for all patients with AsxCS, regardless of whether they will eventually be offered CEA, CAS, or TCAR. Specific patient subgroups at high risk for stroke despite BMT should be considered for a carotid revascularization procedure. These patients include those with severe (≥80%) AsxCS, transcranial Doppler-detected microemboli, plaque echolucency on Duplex ultrasound examination, silent infarcts on brain computed tomography or magnetic resonance angiography scans, decreased cerebrovascular reserve, increased size of juxtaluminal hypoechoic area, AsxCS progression, carotid plaque ulceration, and intraplaque hemorrhage. Treatment of patients with AsxCS should be individualized, taking into consideration individual patient preferences and needs, clinical and imaging characteristics, and cultural, ethnic, and social factors. Solid evidence supporting or refuting an association between AsxCS and cognitive dysfunction is lacking. CONCLUSIONS: The optimal management of patients with AsxCS should include BMT for all individuals and a prophylactic carotid revascularization procedure (CEA, CAS, or TCAR) for some asymptomatic patient subgroups, additionally taking into consideration individual patient needs and preference, clinical and imaging characteristics, social and cultural factors, and the available stroke risk prediction models. Future studies should investigate the association between AsxCS with cognitive function and the role of carotid revascularization procedures in the progression or reversal of cognitive dysfunction.

Serration Angioplasty Is Associated With Less Recoil in Infrapopliteal Arteries Compared With Plain Balloon Angioplasty.

PURPOSE: Recoil following balloon angioplasty of tibial arteries is a known mechanism of lumen loss and widely considered to be a contributing factor in early failure or later restenosis. The Serranator balloon has been designed to provide a controlled lumen gain while minimizing vessel injury. The objective of this study was to assess the ability to define and measure postangioplasty recoil in infrapopliteal arteries and to compare recoil after serration angioplasty and plain balloon angioplasty (POBA). METHODS: This multi-center, sequential comparative study included patients with de novo or restenotic lesions of infrapopliteal arteries up to 22 cm in length. Patients were enrolled sequentially and underwent alternating POBA or serration angioplasty with Serranator. The study captured angiographic imaging at pre, immediately post, and 15-minute after angioplasty. Vessel recoil, final diameter stenosis, and dissection were compared using core laboratory analysis. RESULTS: This study enrolled 36 patients who underwent treatment of 39 infrapopliteal lesions. There was no significant difference between Serranator (n=20) and POBA (n=19) with respect to baseline demographics and lesion characteristics. Arterial recoil (>10%) occurred in 25% of Serranator-treated lesions versus 64% in POBA-treated lesions (p=0.02. Clinically relevant recoil (>30%) was present after serration angioplasty in 10% of patients and after POBA in 53% (p=0.01). There was no significant difference in technical success (100% for both), dissection rate between Serranator (5%) and POBA (5.2%). CONCLUSIONS: Arterial recoil occurs after infrapopliteal angioplasty. Serration angioplasty produces substantially less arterial recoil compared with POBA. Additional studies are needed to assess whether reduced arterial recoil translates into superior long-term clinical outcomes. CLINICAL IMPACT: Prior studies have demonstrated over 90% recoil in patients after balloon angioplasty (POBA) of the infrapopliteal vessels, which significantly impacts the durability and impact of endovascular interventions in this clinical space. This study compared recoil after infrapopliteal angioplasty with serration angioplasty and POBA. Serration angioplasty produces substantially less arterial recoil compared with POBA. Additional studies are needed to assess whether reduced arterial recoil translates into superior long-term clinical outcomes.

How I do it: optimizing angioplasty using the Tack endovascular system in the management of chronic limb threatening ischemia.

Dissection occurring after percutaneous transluminal angioplasty (PTA) is associated with decreased vessel patency and an increased incidence of target lesion revascularization. Management of post-PTA dissection with the Tack Endovascular System (Philips, N.V., Amsterdam, Netherlands) has created an effective and durable treatment strategy for infrainguinal dissections. In this report, we discuss the indications and optimal methods for using Tack devices in post-PTA dissections.

Mortality in randomised controlled trials using paclitaxel-coated devices for femoropopliteal interventional procedures: an updated patient-level meta-analysis.

BACKGROUND: Numerous randomised clinical trials and real-world studies have supported the safety of paclitaxel-coated devices for the treatment of femoropopliteal occlusive disease. However, a 2018 summary-level meta-analysis suggested an increased mortality risk for paclitaxel-coated devices compared with uncoated control devices. This study presents an updated analysis of deaths using the most complete and current data available from pivotal trials of paclitaxel-coated versus control devices. METHODS: Ten trials comparing paclitaxel-coated versus control devices were included in a patient-level pooled analysis. Cox regression models were used to evaluate the effect of paclitaxel exposure on risk of death in both intention-to-treat (ITT; primary analysis) and three as-treated analysis sets accounting for treatment group crossover at the index procedure and over time. The effect of paclitaxel dose and baseline covariates were also evaluated. FINDINGS: A total of 2666 participants were included with a median follow-up of 4·9 years. No significant increase in deaths was observed for patients treated with paclitaxel-coated devices. This was true in the ITT analysis (hazard ratio [HR] 1·14, 95% CI 0·93-1·40), the as-treated analysis (HR 1·13, 95% CI 0·92-1·39), and in two crossover analyses: 1·07 (0·87-1·31) when late crossovers were censored and 1·04 (0·84-1·28) when crossovers were analysed from the date of paclitaxel exposure. There was no significant effect of paclitaxel dose on mortality risk. INTERPRETATION: This meta-analysis found no association between paclitaxel-coated device exposure and risk of death, providing reassurance to patients, physicians, and regulators on the safety of paclitaxel-coated devices. FUNDING: Becton Dickinson, Boston Scientific, Cook, Medtronic, Philips, Surmodics, and TriReme Medical.

Neuroanatomical Disposition, Natural Development, and Training-Induced Plasticity of the Human Auditory System from Childhood to Adulthood: A 12-Year Study in Musicians and Nonmusicians.

Auditory perception is fundamental to human development and communication. However, no long-term studies have been performed on the plasticity of the auditory system as a function of musical training from childhood to adulthood. The long-term interplay between developmental and training-induced neuroplasticity of auditory processing is still unknown. We present results from AMseL (Audio and Neuroplasticity of Musical Learning), the first longitudinal study on the development of the human auditory system from primary school age until late adolescence. This 12-year project combined neurologic and behavioral methods including structural magnetic resonance imaging (MRI), magnetoencephalography (MEG), and auditory tests. A cohort of 112 typically developing participants (51 male, 61 female), classified as "musicians" (n = 66) and "nonmusicians" (n = 46), was tested at five measurement timepoints. We found substantial, stable differences in the morphology of auditory cortex (AC) between musicians and nonmusicians even at the earliest ages, suggesting that musical aptitude is manifested in macroscopic neuroanatomical characteristics. Maturational plasticity led to a continuous increase in white matter myelination and systematic changes of the auditory evoked P1-N1-P2 complex (decreasing latencies, synchronization effects between hemispheres, and amplitude changes) regardless of musical expertise. Musicians showed substantial training-related changes at the neurofunctional level, in particular more synchronized P1 responses and bilaterally larger P2 amplitudes. Musical training had a positive influence on elementary auditory perception (frequency, tone duration, onset ramp) and pattern recognition (rhythm, subjective pitch). The observed interplay between "nature" (stable biological dispositions and natural maturation) and "nurture" (learning-induced plasticity) is integrated into a novel neurodevelopmental model of the human auditory system.Significance Statement We present results from AMseL (Audio and Neuroplasticity of Musical Learning), a 12-year longitudinal study on the development of the human auditory system from childhood to adulthood that combined structural magnetic resonance imaging (MRI), magnetoencephalography (MEG), and auditory discrimination and pattern recognition tests. A total of 66 musicians and 46 nonmusicians were tested at five timepoints. Substantial, stable differences in the morphology of auditory cortex (AC) were found between the two groups even at the earliest ages, suggesting that musical aptitude is manifested in macroscopic neuroanatomical characteristics. We also observed neuroplastic and perceptual changes with age and musical practice. This interplay between "nature" (stable biological dispositions and natural maturation) and "nurture" (learning-induced plasticity) is integrated into a novel neurodevelopmental model of the human auditory system.