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1.
Plast Reconstr Surg Glob Open ; 11(7): e5120, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37448761

RESUMO

In this report, we present a 57-year-old man with chronic bilateral lower extremity wounds from nonuremic calciphylaxis, which were successfully reconstructed using a piscine-derived acellular dermal matrix. The acellular dermal matrix incorporated quickly, providing a wound bed that was amenable to skin grafting. We demonstrate that this is an effective off-the-shelf solution for these chronic wounds, resulting in pain reduction and complete closure of the wounds, allowing the patient to return to his previous baseline activities, and improving his quality of life.

2.
J Reconstr Microsurg ; 39(1): 70-80, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-35764300

RESUMO

BACKGROUND: Microvascular hepatic artery reconstruction (MHAR) is associated with decreased rates of hepatic artery thrombosis (HAT) in living donor liver transplantation (LDLT). There is a paucity of literature describing the learning points and initiation of this technique at the institutional level. The objective of this study is to report our institutional experience using MHAR in adult LDLT with a focus on technique and outcomes. METHODS: A retrospective review of adult patients who underwent LDLT from January 2012 to December 2020 was conducted. Patients were divided into two groups, those who underwent LDLT without MHAR and with MHAR. We analyzed cases for technical data including donor and recipient artery characteristics, anastomotic techniques, intraop events, and postop complications. A Mann-Whitney test was performed to compare outcomes between non-MHAR and MHAR patients. RESULTS: Fifty non-MHAR and 50 MHAR patients met inclusion criteria. Median age at transplantation was 58 (interquartile range [IQR] 11.8) and 57.5 years (IQR 14.5), respectively. Median follow-up for MHAR patients was 12.8 months (IQR 11.6). The most common recipient arteries were the right hepatic artery (HA) (58%) and left HA (20%). Median size of recipient and donor arteries were 3.3 mm (IQR 0.7) and 3.1 mm (IQR 0.7), resulting in a median mismatch size of 0.3 mm (IQR 0.4). Median microanastomosis time was 44 minutes (IQR 0). HAT, graft failure, and mortality rates were higher in the non-MHAR cohort (6% vs. 0%, 8% vs. 0%, and 16% vs. 6%, respectively); however, these did not reach statistical significance. CONCLUSION: This study found lower rates of HAT and graft failure after implementing MHAR, though statistical significance was not achieved. Larger cohort studies are needed to further assess the potential benefit of MHAR in adult LDLT. From our experience, MHAR requires cooperation between the transplant and microsurgical teams, with technical challenges overcome with appropriate instrumentation and planning.


Assuntos
Transplante de Fígado , Trombose , Humanos , Adulto , Criança , Transplante de Fígado/efeitos adversos , Transplante de Fígado/métodos , Doadores Vivos , Resultado do Tratamento , Artéria Hepática/cirurgia , Trombose/etiologia , Estudos Retrospectivos , Anastomose Cirúrgica/efeitos adversos
3.
Burns ; 49(1): 15-25, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-35842270

RESUMO

INTRODUCTION: Mucormycosis is an opportunistic fungal infection with a high mortality rate. Though typically associated with diabetes and other conditions that affect innate immune function, infections can also be precipitated by conditions such as trauma and burns. Burn patients are particularly susceptible to fungal infections due to the immune dysfunction that often accompany their wounds. Indeed case series have described mucormycosis to occur in patients with burn injuries, however the factors contributing to mortality have not been well described. Thus, the purpose of our review was to identify factors contributing to morbidity and mortality in burn patients with Mucormycosis. METHODS: A systematic review of the literature of mucormycosis infection in burn injury patients was performed on Pubmed and Google Scholar using the keywords: Mucor, Mucorales, Mucormycosis, Mucormycotina, Zygomycosis and burn or thermal injury. Clinical trials, observational studies, case reports, and case reviews were included if they provided information regarding mortality in adult and pediatric burn patients diagnosed with mucormycosis, review articles, non-English articles, and articles without patient information were excluded. No time limit was placed on our review. Individual patient data was stratified based on mortality. Statistical analysis was performed to investigate the relationship between patient risk factors and mortality, and the Oxford Level of Evidence was used to evaluate study quality. RESULTS: 46 articles were included in our final review, encompassing 114 patients. On average, survivors had a total body surface area (TBSA)% of 46 (SD 19.8) while non-survivors had a TBSA of 65% (SD 16.4), and this difference was significant (p < .001). Patients with disseminated mucormycosis experienced an 80% mortality rate compared to 36% mortality rate in patients with localized disease (p < .001). We found no statistically significant difference in mean age (p > .05), diabetes (p > .05), mean delay in diagnosis (p > .05), time to antifungal therapy (p > .05), or type of therapy used (p > .05) between survivors and non-survivors. Our review was limited by the lack of prospective, controlled trials; thus, our review primarily consists of case reports. CONCLUSION: Disseminated infections and higher TBSA both increased the risk of mortality in burn patients with mucormycosis, while diabetes did not increase mortality risk. The severity of the initial injury and infection locations must be taken into consideration to inform patient prognosis.


Assuntos
Queimaduras , Mucormicose , Adulto , Humanos , Criança , Queimaduras/terapia , Mucormicose/epidemiologia , Mucormicose/diagnóstico , Mucormicose/microbiologia , Fatores de Risco , Prognóstico , Estudos Retrospectivos
4.
Can J Psychiatry ; 67(10): 745-754, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-35522196

RESUMO

OBJECTIVES: To determine the efficacy and safety of blue-light therapy in seasonal and non-seasonal major depressive disorder (MDD), by comparison to active and inactive control conditions. METHODS: We searched Web of Science, EMBASE, Medline, PsycInfo, and Clinicaltrials.gov through January 17, 2022, for randomized controlled trials (RCTs) using search terms for blue/blue-enhanced, light therapy, and depression/seasonal affective disorder. Two independent reviewers extracted data. The primary outcome was the difference in endpoint scores on the Structured Interview Guide for the Hamilton Depression Rating Scale - Seasonal Affective Disorder (SIGH-SAD) or the Structured Interview Guide for the Hamilton Depression Rating Scale with Atypical Depression Supplement (SIGH-ADS) between blue light and comparison conditions. Secondary outcomes were response (≥ 50% improvement from baseline to endpoint on a depression scale) and remission rates (endpoint score in the remission range). RESULTS: Of 582 articles retrieved, we included nine RCTs (n = 347 participants) assessing blue-light therapy. Seven studies had participants with seasonal MDD and two studies included participants with non-seasonal MDD. Four studies compared blue light to an inactive light condition (efficacy studies), and five studies compared it to an active condition (comparison studies). For the primary outcome, a meta-analysis with random-effects models found no evidence for the efficacy of blue-light conditions compared to inactive conditions (mean difference [MD] = 2.43; 95% confidence interval [CI], -1.28 to 6.14, P = 0.20); however, blue-light also showed no differences compared to active conditions (MD = -0.11; 95% CI, -2.38 to 2.16, P = 0.93). There were no significant differences in response and remission rates between blue-light conditions and inactive or active light conditions. Blue-light therapy was overall well-tolerated. CONCLUSIONS: The efficacy of blue-light therapy in the treatment of seasonal and non-seasonal MDD remains unproven. Future trials should be of longer duration, include larger sample sizes, and attempt to better standardize the parameters of light therapy.


Assuntos
Transtorno Depressivo Maior , Transtorno Afetivo Sazonal , Depressão , Transtorno Depressivo Maior/terapia , Humanos , Fototerapia , Ensaios Clínicos Controlados Aleatórios como Assunto , Transtorno Afetivo Sazonal/terapia
5.
Case Rep Infect Dis ; 2022: 7250294, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35480341

RESUMO

A 67-year-old male presented with complaints of weakness, fatigue, and shortness of breath in the context of a recent hospitalization for the same unresolved symptoms. After a largely nonspecific clinical presentation, a chest X-ray revealed a loculated pleural effusion. Culture of the postthoracentesis exudate revealed the culprit to be the aerobic Gram-negative bacterium Francisella tularensis. Amidst reports of potential resurgence, clinicians should be aware of the possible presentations of tularemia and consider it in the case of an ostensibly contributory patient history.

6.
J Surg Oncol ; 126(2): 217-238, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35389520

RESUMO

Cutaneous metastases (CM) are neoplastic lesions involving the dermis or subcutaneous tissues, originating from another primary tumor. Breast cancer is commonest primary solid tumor, representing 24%-50% of CM patients. There is no "standard of care" on management. In particular, the role of surgery in the treatment of cutaneous metastases from breast carcinoma (CMBC) remains controversial. This systematic review evaluates the role of cutaneous metastasectomy in breast cancer and provides an overview of existing treatment types.


Assuntos
Neoplasias da Mama , Neoplasias Pulmonares , Metastasectomia , Neoplasias Cutâneas , Neoplasias da Mama/patologia , Neoplasias da Mama/cirurgia , Feminino , Humanos , Neoplasias Pulmonares/cirurgia
7.
Eur J Trauma Emerg Surg ; 48(3): 2275-2286, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-34357407

RESUMO

PURPOSE: Rapid sequence intubation (RSI) in trauma patients is common; however, the induction agents used have been debated. We determined which induction medications were used most frequently for adult trauma RSIs and their associations with hemodynamics and outcomes. We hypothesized that etomidate is the most commonly used induction agent and has similar outcomes to other induction agents. METHODS: This retrospective review at two U.S. level I trauma centers evaluated adult trauma patients undergoing RSI within 24 h of admission, between 01/01/2016 and 12/31/2017. We compared patient characteristics and outcomes by induction agent. Comparisons on the primary outcome of in-hospital mortality and secondary outcomes of peri-intubation hypotension, hospital and ICU length of stay (LOS), ventilator days, and complications used logistic regression or negative binomial regression. Regression models adjusted for hospital site, age, patient severity measures, and intubation location. RESULTS: Among 1303 trauma patients undergoing RSI within 24 h of admission, 948 (73%) were intubated in the emergency department (ED) and 325 (25%) in the operating room (OR). The most common induction agents were etomidate (68%), propofol (17%), and ketamine (11%). In-hospital mortality was highest in the etomidate group (25.5%), followed by ketamine (17%), and propofol (1.8%). CONCLUSION: Etomidate was most commonly used in ED intubations; propofol was most used in the OR. Compared to propofol, patients induced with etomidate had higher mortality and complication rates. Findings should be interpreted with caution given limited generalizability and residual confounding by indication.


Assuntos
Etomidato , Ketamina , Propofol , Adulto , Análise de Dados , Etomidato/uso terapêutico , Humanos , Intubação Intratraqueal , Ketamina/uso terapêutico , Propofol/efeitos adversos , Indução e Intubação de Sequência Rápida , Estudos Retrospectivos
8.
J Burn Care Res ; 43(2): 368-373, 2022 03 23.
Artigo em Inglês | MEDLINE | ID: mdl-34534314

RESUMO

Pain following burn injury is associated with long-term health consequences in the pediatric population. Literature suggests nonpharmacologic treatment may provide improved pain control as an effective adjunct for these patients. This study aims to summarize randomized controlled trials on nonpharmacologic procedural pain management in pediatric burn patients. A systematic review was conducted on nonpharmacologic procedural pain management techniques used in the pediatric burn population. Fifteen studies were included and involved virtual reality, distraction devices, child life therapy, directed play, digital tablet games, cartoons, hypnosis, and music therapy. Treatment was effective in 8 out of 15 studies. Compared to controls, nonpharmacologic treatments reduced mid procedure pain by 19.7% and post-procedure pain by 20.1%. This study demonstrates that nonpharmacologic therapy can be an effective adjunct in pediatric procedural burn pain management, however further studies are needed to develop standardized algorithms to integrate nonpharmacologic treatments with pharmacologic therapies.


Assuntos
Queimaduras , Dor Processual , Queimaduras/complicações , Queimaduras/terapia , Criança , Humanos , Dor/etiologia , Manejo da Dor/métodos , Dor Processual/etiologia , Dor Processual/prevenção & controle , Ensaios Clínicos Controlados Aleatórios como Assunto
9.
J Community Health ; 47(1): 127-135, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-34480684

RESUMO

Tattoos of formerly gang-involved and incarcerated individuals can negatively impact their ability to reintegrate into society. Laser tattoo removal is essential to helping individuals obtain employment, re-cultivate positive relationships, and disengage from gangs. The objective of this study is to describe the demographics and motivations for laser tattoo removal at a large nonprofit clinic. This was a single center retrospective study conducted on patients presenting to Ya'stuvo Tattoo Removal between January 2016-December 2018 and had at least three laser tattoo removal sessions. Data was recorded on patient demographics, geographic location of residence (e.g. zipcode), comorbidities, probation/parole status, referral source, transportation mode, and motivations for receiving and removing tattoos. A representative sample of 862 patients was used to conduct our analysis. Average age at first visit was 30. 16% (n = 134) were on probation, 8% (n = 66) were on parole, and 63% (n = 544) did not report their probation/parole status. Reasons for receiving a tattoo included gangs (46%, n = 368), a current or ex-relationship (28%, n = 223), and decoration (20%, n = 159). The most common reasons for tattoo removal were employment (66%, n = 546), readiness to change life (47%, n = 392), maturity (47%, n = 392), family (43%, n = 356), and negative attention from tattoos (37%, n = 303). The current study highlights the importance of laser tattoo removal in reintegration and gang disengagement. Expanding cost efficient laser tattoo removal is paramount to meet the safety and socioeconomic needs of this population.


Assuntos
Tatuagem , Humanos , Lasers , Motivação , Estudos Retrospectivos , Populações Vulneráveis
10.
Burns ; 47(8): 1691-1704, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34419331

RESUMO

BACKGROUND: Visual evaluation is the most common method of evaluating burn wounds. Its subjective nature can lead to inaccurate diagnoses and inappropriate burn center referrals. Machine learning may provide an objective solution. The objective of this study is to summarize the literature on ML in burn wound evaluation. METHODS: A systematic review of articles published between January 2000 and January 2021 was performed using PubMed and MEDLINE (OVID). Articles reporting on ML or automation to evaluate burn wounds were included. Keywords included burns, machine/deep learning, artificial intelligence, burn classification technology, and mobile applications. Data were extracted on study design, method of data acquisition, machine learning techniques, and machine learning accuracy. RESULTS: Thirty articles were included. Nine studies used machine learning and automation to estimate percent total body surface area (%TBSA) burned, 4 calculated fluid estimations, 19 estimated burn depth, 5 estimated need for surgery, and 2 evaluated scarring. Models calculating %TBSA burned demonstrated accuracies comparable to or better than paper methods. Burn depth classification models achieved accuracies of >83%. CONCLUSION: Machine learning provides an objective adjunct that may improve diagnostic accuracy in evaluating burn wound severity. Existing models remain in the early stages with future studies needed to assess their clinical feasibility.


Assuntos
Inteligência Artificial , Queimaduras , Automação , Superfície Corporal , Humanos , Aprendizado de Máquina
12.
J Burn Care Res ; 2021 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-34120173

RESUMO

INTRODUCTION: Burn wound depth assessments are an important component of determining patient prognosis and making appropriate management decisions. Clinical appraisal of the burn wound by an experienced burn surgeon is standard of care but has limitations. IR thermography is a technology in burn care that can provide a non-invasive, quantitative method of evaluating burn wound depth. IR thermography utilizes a specialized camera that can capture the infrared emissivity of the skin, and the resulting images can be analyzed to determine burn depth and healing potential of a burn wound. Though IR thermography has great potential for burn wound assessment, its use for this has not been well documented. Thus, we have conducted a systematic review of the current use of IR thermography to assess burn depth and healing potential. METHODS: A systematic review and meta-analysis of the literature was performed on PubMed and Google Scholar between June 2020-December 2020 using the following keywords: FLIR, FLIR ONE, thermography, forward looking infrared, thermal imaging + burn*, burn wound assessment, burn depth, burn wound depth, burn depth assessment, healing potential, burn healing potential. A meta-analysis was performed on the mean sensitivity and specificity of the ability of IR thermography for predicting healing potential. Inclusion criteria were articles investigating the use of IR thermography for burn wound assessments in adults and pediatric patients. Reviews and non-English articles were excluded. RESULTS: A total of 19 articles were included in the final review. Statistically significant correlations were found between IR thermography and laser doppler imaging (LDI) in 4/4 clinical studies. A case report of a single patient found that IR thermography was more accurate than LDI for assessing burn depth. Five articles investigated the ability of IR thermography to predict healing time, with four reporting statistically significant results. Temperature differences between burnt and unburnt skin were found in 2/2 articles. IR thermography was compared to clinical assessment in five articles, with varying results regarding accuracy of clinical assessment compared to thermography. Mean sensitivity and specificity of the ability of IR thermography to determine healing potential <15 days was 44.5 and 98.8 respectively. Mean sensitivity and specificity of the ability of FLIR to determine healing potential <21 days was 51.2 and 77.9 respectively. CONCLUSION: IR thermography is an accurate, simple, and cost-effective method of burn wound assessment. FLIR has been demonstrated to have significant correlations with other methods of assessing burns such as LDI and can be utilized to accurately assess burn depth and healing potential.

13.
J Burn Care Res ; 42(5): 886-893, 2021 09 30.
Artigo em Inglês | MEDLINE | ID: mdl-34058010

RESUMO

Tent fires are a growing issue in regions with large homeless populations given the rise in homelessness within the United States and existing data that suggest worse outcomes in this population. The aim of this study was to describe the characteristics and outcomes of tent fire burn injuries in the homeless population. A retrospective review was conducted involving two verified regional burn centers with patients admitted for tent fire burns between January 2015 and December 2020. Variables recorded include demographics, injury characteristics, hospital course, and patient outcomes. Sixty-nine patients met the study inclusion criteria. The most common mechanisms of injury were by portable stove accident, assault, and tobacco or methamphetamine related. Median percent total body surface area (%TBSA) burned was 6% (interquartile range [IQR] 9%). Maximum depth of injury was partial thickness in 65% (n = 45) and full thickness in 35% (n = 24) of patients. Burns to the upper and lower extremities were present in 87% and 54% of patients, respectively. Median hospital length of stay (LOS) was 10 days (IQR = 10.5) and median ICU LOS was 1 day (IQR = 5). Inhalation injury was present in 14% (n = 10) of patients. Surgical intervention was required in 43% (n = 30) of patients, which included excision, debridement, skin grafting, and escharotomy. In-hospital mortality occurred in 4% (n = 3) of patients. Tent fire burns are severe enough to require inpatient and ICU level of care. A high proportion of injuries involved the extremities and pose significant barriers to functional recovery in this vulnerable population. Strategies to prevent these injuries are paramount.


Assuntos
Acidentes/estatística & dados numéricos , Queimaduras/epidemiologia , Incêndios/estatística & dados numéricos , Pessoas Mal Alojadas/estatística & dados numéricos , Adulto , Superfície Corporal , Queimaduras/diagnóstico , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Fatores de Risco , Adulto Jovem
14.
AMIA Annu Symp Proc ; 2021: 1039-1048, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-35308958

RESUMO

Burn wounds are most commonly evaluated through visual inspection to determine surgical candidacy, taking into account burn depth and individualized patient factors. This process, though cost effective, is subjective and varies by provider experience. Deep learning models can assist in burn wound surgical candidacy with predictions based on the wound and patient characteristics. To this end, we present a multimodal deep learning approach and a complementary mobile application - DL4Burn - for predicting burn surgical candidacy, to emulate the multi-factored approach used by clinicians. Specifically, we propose a ResNet50-based multimodal model and validate it using retrospectively obtained patient burn images, demographic, and injury data.


Assuntos
Queimaduras , Aprendizado Profundo , Queimaduras/cirurgia , Humanos , Estudos Retrospectivos
15.
Environ Pollut ; 268(Pt B): 115840, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33120158

RESUMO

The effect of plant roots in modifying Pb solubility and bioavailability in an historically contaminated orchard (Hudson) and a Pb phosphate-spiked (Arkport) soil was determined by measuring soluble Pb in the soil solutions as well as content of Pb in radish shoots grown in these soils. Soluble Pb and dissolved organic carbon (DOC) contents were greater in the rhizospheres of both Pb-contaminated soils than in the unplanted high-Pb soils. The rhizosphere effect increased soluble Pb 15-fold in the field-contaminated orchard soil, whereas the effect was much smaller in the Pb phosphate-spiked soil. The rhizosphere effect persisted in the Pb-phosphate spiked soil after adjustment of the soil pH from 7.8 to 6.7. The results indicate that Pb phosphate added to a non-acid soil has lower solubility than Pb in an orchard soil contaminated by historical Pb arsenate applications; nevertheless, some uptake of Pb into plant shoots resulted from both sources of soil Pb contamination. The rhizosphere effect was observed for trace metals in addition to Pb, with the solubility of Al, Fe, Cu and Ni all increasing in the rhizosphere soil. In contrast, the solubility of alkali and alkaline earth metals (K, Ca, Mg, Sr, Ba) all decreased in the rhizosphere soil. The results indicate that the rhizosphere effect associated with plant roots can raise the solubility of Pb in soils contaminated by legacy Pb and by insoluble Pb phosphate.


Assuntos
Rizosfera , Poluentes do Solo , Chumbo , Solo , Poluentes do Solo/análise , Solubilidade
16.
Brain Topogr ; 33(4): 477-488, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32441009

RESUMO

Auditory attention allows us to focus on relevant target sounds in the acoustic environment while maintaining the capability to orient to unpredictable (novel) sound changes. An open question is whether orienting to expected vs. unexpected auditory events are governed by anatomically distinct attention pathways, respectively, or by differing communication patterns within a common system. To address this question, we applied a recently developed PeSCAR analysis method to evaluate spectrotemporal functional connectivity patterns across subregions of broader cortical regions of interest (ROIs) to analyze magnetoencephalography data obtained during a cued auditory attention task. Subjects were instructed to detect a predictable harmonic target sound embedded among standard tones in one ear and to ignore the standard tones and occasional unpredictable novel sounds presented in the opposite ear. Phase coherence of estimated source activity was calculated between subregions of superior temporal, frontal, inferior parietal, and superior parietal cortex ROIs. Functional connectivity was stronger in response to target than novel stimuli between left superior temporal and left parietal ROIs and between left frontal and right parietal ROIs, with the largest effects observed in the beta band (15-35 Hz). In contrast, functional connectivity was stronger in response to novel than target stimuli in inter-hemispheric connections between left and right frontal ROIs, observed in early time windows in the alpha band (8-12 Hz). Our findings suggest that auditory processing of expected target vs. unexpected novel sounds involves different spatially, temporally, and spectrally distributed oscillatory connectivity patterns across temporal, parietal, and frontal areas.


Assuntos
Atenção , Córtex Auditivo , Percepção Auditiva , Magnetoencefalografia , Estimulação Acústica , Mapeamento Encefálico , Feminino , Humanos , Lobo Parietal
17.
Neuroimage ; 208: 116436, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31809885

RESUMO

Auditory distance perception and its neuronal mechanisms are poorly understood, mainly because 1) it is difficult to separate distance processing from intensity processing, 2) multiple intensity-independent distance cues are often available, and 3) the cues are combined in a context-dependent way. A recent fMRI study identified human auditory cortical area representing intensity-independent distance for sources presented along the interaural axis (Kopco et al. PNAS, 109, 11019-11024). For these sources, two intensity-independent cues are available, interaural level difference (ILD) and direct-to-reverberant energy ratio (DRR). Thus, the observed activations may have been contributed by not only distance-related, but also direction-encoding neuron populations sensitive to ILD. Here, the paradigm from the previous study was used to examine DRR-based distance representation for sounds originating in front of the listener, where ILD is not available. In a virtual environment, we performed behavioral and fMRI experiments, combined with computational analyses to identify the neural representation of distance based on DRR. The stimuli varied in distance (15-100 â€‹cm) while their received intensity was varied randomly and independently of distance. Behavioral performance showed that intensity-independent distance discrimination is accurate for frontal stimuli, even though it is worse than for lateral stimuli. fMRI activations for sounds varying in frontal distance, as compared to varying only in intensity, increased bilaterally in the posterior banks of Heschl's gyri, the planum temporale, and posterior superior temporal gyrus regions. Taken together, these results suggest that posterior human auditory cortex areas contain neuron populations that are sensitive to distance independent of intensity and of binaural cues relevant for directional hearing.


Assuntos
Córtex Auditivo/fisiologia , Percepção Auditiva/fisiologia , Mapeamento Encefálico , Sinais (Psicologia) , Percepção de Distância/fisiologia , Adulto , Córtex Auditivo/diagnóstico por imagem , Discriminação Psicológica/fisiologia , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Modelos Teóricos , Vias Neurais/fisiologia , Psicofísica , Adulto Jovem
18.
Rev Sci Instrum ; 88(9): 094302, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28964218

RESUMO

Spatial Frequency Domain Spectroscopy (SFDS) is a technique for quantifying in-vivo tissue optical properties. SFDS employs structured light patterns that are projected onto tissues using a spatial light modulator, such as a digital micromirror device. In combination with appropriate models of light propagation, this technique can be used to quantify tissue optical properties (absorption, µa, and scattering, µs', coefficients) and chromophore concentrations. Here we present a handheld implementation of an SFDS device that employs line (one dimensional) imaging. This instrument can measure 1088 spatial locations that span a 3 cm line as opposed to our original benchtop SFDS system that only collects a single 1 mm diameter spot. This imager, however, retains the spectral resolution (∼1 nm) and range (450-1000 nm) of our original benchtop SFDS device. In the context of homogeneous turbid media, we demonstrate that this new system matches the spectral response of our original system to within 1% across a typical range of spatial frequencies (0-0.35 mm-1). With the new form factor, the device has tremendously improved mobility and portability, allowing for greater ease of use in a clinical setting. A smaller size also enables access to different tissue locations, which increases the flexibility of the device. The design of this portable system not only enables SFDS to be used in clinical settings but also enables visualization of properties of layered tissues such as skin.


Assuntos
Pele , Análise Espectral/instrumentação
19.
Neuroimage ; 161: 1-8, 2017 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-28818692

RESUMO

Auditory working memory (WM) processing in everyday acoustic environments depends on our ability to maintain relevant information online in our minds, and to suppress interference caused by competing incoming stimuli. A challenge in communication settings is that the relevant content and irrelevant inputs may emanate from a common source, such as a talkative conversationalist. An open question is how the WM system deals with such interference. Will the distracters become inadvertently filtered before processing for meaning because the primary WM operations deplete all available processing resources? Or are they suppressed post perceptually, through an active control process? We tested these alternative hypotheses by measuring magnetoencephalography (MEG), EEG, and functional MRI (fMRI) during a phonetic auditory continuous performance task. Contextual WM maintenance load was manipulated by adjusting the number of "filler" letter sounds in-between cue and target letter sounds. Trial-to-trial variability of pre- and post-stimulus activations in fMRI-informed cortical MEG/EEG estimates was analyzed within and across 14 subjects using generalized linear mixed effect (GLME) models. High contextual WM maintenance load suppressed left auditory cortex (AC) activations around 250-300 ms after the onset of irrelevant phonetic sounds. This effect coincided with increased 10-14 Hz alpha-range oscillatory functional connectivity between the left dorsolateral prefrontal cortex (DLPFC) and left AC. Suppression of AC responses to irrelevant sounds during active maintenance of the task context also correlated with increased pre-stimulus 7-15 Hz alpha power. Our results suggest that under high auditory WM load, irrelevant sounds are suppressed through a "late" active suppression mechanism, which prevents short-term consolidation of irrelevant information without affecting the initial screening of potentially meaningful stimuli. The results also suggest that AC alpha oscillations play an inhibitory role during auditory WM processing.


Assuntos
Ritmo alfa/fisiologia , Atenção/fisiologia , Córtex Auditivo/fisiologia , Percepção Auditiva/fisiologia , Conectoma/métodos , Magnetoencefalografia/métodos , Memória de Curto Prazo/fisiologia , Córtex Pré-Frontal/fisiologia , Adulto , Córtex Auditivo/diagnóstico por imagem , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Córtex Pré-Frontal/diagnóstico por imagem , Adulto Jovem
20.
Neuroimage ; 143: 116-127, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27608603

RESUMO

Despite recent advances in auditory neuroscience, the exact functional organization of human auditory cortex (AC) has been difficult to investigate. Here, using reversals of tonotopic gradients as the test case, we examined whether human ACs can be more precisely mapped by avoiding signals caused by large draining vessels near the pial surface, which bias blood-oxygen level dependent (BOLD) signals away from the actual sites of neuronal activity. Using ultra-high field (7T) fMRI and cortical depth analysis techniques previously applied in visual cortices, we sampled 1mm isotropic voxels from different depths of AC during narrow-band sound stimulation with biologically relevant temporal patterns. At the group level, analyses that considered voxels from all cortical depths, but excluded those intersecting the pial surface, showed (a) the greatest statistical sensitivity in contrasts between activations to high vs. low frequency sounds and (b) the highest inter-subject consistency of phase-encoded continuous tonotopy mapping. Analyses based solely on voxels intersecting the pial surface produced the least consistent group results, even when compared to analyses based solely on voxels intersecting the white-matter surface where both signal strength and within-subject statistical power are weakest. However, no evidence was found for reduced within-subject reliability in analyses considering the pial voxels only. Our group results could, thus, reflect improved inter-subject correspondence of high and low frequency gradients after the signals from voxels near the pial surface are excluded. Using tonotopy analyses as the test case, our results demonstrate that when the major physiological and anatomical biases imparted by the vasculature are controlled, functional mapping of human ACs becomes more consistent from subject to subject than previously thought.


Assuntos
Córtex Auditivo/fisiologia , Mapeamento Encefálico/métodos , Córtex Cerebral/diagnóstico por imagem , Veias Cerebrais/diagnóstico por imagem , Pia-Máter/diagnóstico por imagem , Percepção da Fala/fisiologia , Adulto , Córtex Auditivo/diagnóstico por imagem , Mapeamento Encefálico/normas , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Pia-Máter/irrigação sanguínea , Adulto Jovem
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