Perinatal Asphyxia Affects Rat Auditory Processing: Implications for Auditory Perceptual Impairments in Neurodevelopmental Disorders

Perinatal asphyxia, a naturally and commonly occurring risk factor in birthing, represents one of the major causes of neonatal encephalopathy with long term consequences for infants. Here, degraded spectral and temporal responses to sounds were recorded from neurons in the primary auditory cortex (A1) of adult rats exposed to asphyxia at birth. Response onset latencies and durations were increased. Response amplitudes were reduced. Tuning curves were broader. Degraded successive-stimulus masking inhibitory mechanisms were associated with a reduced capability of neurons to follow higher-rate repetitive stimuli. The architecture of peripheral inner ear sensory epithelium was preserved, suggesting that recorded abnormalities can be of central origin. Some implications of these findings for the genesis of language perception deficits or for impaired language expression recorded in developmental disorders, such as autism spectrum disorders, contributed to by perinatal asphyxia, are discussed

Speech recognition ability of children with unilateral sensorineural hearing loss as a function of amplification, speech stimuli and listening condition

The purpose of this investigation was to examine three types of audiological ecommendations [unaided, CROS (contralateral routing of signals) and personal FM system] and their impact upon speech recognition ability of children with unilateral sensorineural hearing loss. Each of these recommendations was tested under three listening conditions encountered in a classroom [monaural direct (MD), monaural indirect (MI), midline signal/omnidirectional noise (MS/ON)] with two types of speech materials (Nonsense Syllable Test and an American English adaptation on the Bamford-Kowal-Bench Sentence Lists). These experimental conditions were simulated in a classroom, recorded on audiotape, and played back to subjects under headphones to control such factors as signal-to-noise ratio, earmold fit, and head shadow effects. Six schoolage children with unilateral hearing losses between 56 and >120 dB HL (PTA) were evaluated using a repeated measures design. The children experienced the most listening difficulty in the MI condition when they were unaided. The CROS aid improved speech recognition in this condition but degraded speech recognition in the MD condition. The FM system was the only audiological recommendation to produce uniformly high speech recognition scores across all listening conditions with both types of speech materials. Implications for the audiological management of unilaterally hearing-impaired children in the classroom are discussed. © 1990 by The Williams and Wilkins Co.Link_to_subscribed_fulltex

ACTIGRAHY-DERIVED SLEEP QUALITY AND BLOOD PRESSURE REACTIVITY IN YOUNG APPARENTLY HEALTHY ADULTS

Meral N. Culver, Braxton A. Linder, McKenna A. Tharpe, Alex M. Barnett, Zach J. Hutchison, Austin T. Robinson. Auburn University, Auburn, AL. BACKGROUND: Insufficient sleep is associated with hypertension, the leading risk factor for cardiovascular disease. Blood pressure (BP) responses to physical stressors such as exercise, have prognostic value in predicting future hypertension risk. However, it is unclear whether sleep is associated with BP responses to physical stressors. Thus, the present investigation sought to assess the relation between habitual sleep quality and BP responses during isometric handgrip (HG). METHODS: A total of 49 healthy adults (30 female, age: 23.0±3.3 yrs, BMI: 25.5±3.8 kg/m2, resting BP: 107±10 mmHg, Mean±SD) participated in this study. Objective sleep quality, including sleep duration and efficiency, were assessed using wrist-worn Philips Actiwatch Spectrum PLUS accelerometers. Participants wore the devices for a minimum of a six-day observation period (7.4±0.8 days). Maximal HG force was obtained by calculating the average of three maximal voluntary contractions (MVC). Beat-to-beat BP via finger photoplethysmography (Finometer) and heart rate (electrocardiogram) were continuously assessed during a 10-minute baseline and a two-minute HG at 40% MVC. We split participants into quartiles based on the sleep duration and efficiency, respectively. Statistical analyses included Pearson’s correlation and ANOVA, and significance was set as p\u3c0.05. RESULTS: There were no associations between sleep duration or efficiency and peak (minute two) Δ systolic BP, Δ diastolic BP, or Δ mean BP (p\u3e0.05 for each). Although there was a large difference between quartiles, for sleep duration (Q1:5.9±0.54hrs, Q2:7.1± 0.3hrs, Q3:7.7 ± 0.1hrs, Q4:8.4 ± 0.6hrs p\u3c0.001), and efficiency (Q1:77±5.0%, Q2:84±1.3%, Q3: 88±1.0%, Q4: 91±1.3%, p\u3c0.001), there were not differences between sleep duration quartile groups for peak Δ systolic BP (Q1: 36±14, Q2: 31±24, Q3: 33±16, Q4: 36±15 mmHg, p=0.467), Δ diastolic BP, or Δ mean BP (data not shown, p\u3e0.05 for both). Also, there were no differences between sleep efficiency quartile groups for peak Δ systolic BP, Δ diastolic BP, or Δ mean BP during HG (p\u3e0.05 for each). CONCLUSION: These preliminary data indicate that actigraphy-derived habitual sleep duration and efficiency do not appear to be associated with BP responses to HG exercise in healthy adults. ACKNOWLEDGEMENTS: Funding for this project was provided by NIH grants K01HL147998 and UL1TR003096 (CCTS Pilot), and the 2020 Auburn University School of Kinesiology Seed Funding Competition

Processamento temporal, localização e fechamento auditivo em portadores de perda auditiva unilateral Temporal processing, localization and auditory closure in individuals with unilateral hearing loss

OBJETIVO: Avaliar os comportamentos de resolução e ordenação temporal, localização sonora e fechamento auditivo e investigar queixas de dificuldades escolares, de comunicação e linguagem em indivíduos portadores de perda auditiva unilateral. MÉTODOS: Participaram 26 indivíduos com idades entre 8 e 15 anos, divididos em dois grupos: Grupo com perda auditiva unilateral; e Grupo sem perda auditiva. Cada um deles foi constituído por 13 indivíduos que foram pareados conforme gênero, idade e escolaridade. Todos foram submetidos à anamnese, avaliação auditiva periférica e aos testes comportamentais de localização, memória sequencial, teste Random Gap Detection e ao teste de fala com ruído branco da avaliação do processamento auditivo. Foram utilizados testes estatísticos não paramétricos para comparar as repostas entre os grupos, considerando presença ou não da perda auditiva e o lado da orelha com perda. RESULTADOS: O início da perda ocorreu na fase pré-escolar, com etiologias desconhecidas ou identificadas como meningite, traumas ou caxumba. A maior parte dos indivíduos relatou atraso no desenvolvimento de fala, linguagem e escolar, principalmente aqueles com perda à direita. O grupo com perda auditiva apresentou piores respostas nas habilidades de ordenação e resolução temporal, localização sonora e fechamento auditivo. Indivíduos com perda à esquerda mostraram resultados piores do que aqueles com perda à direita em todas as habilidades, exceto na localização sonora. CONCLUSÃO: Na presença da perda auditiva unilateral ocorrem dificuldades de localização, fechamento, resolução e ordenação temporal. Indivíduos com perda auditiva unilateral à direita apresentam mais queixas do que aqueles com perda à esquerda. Indivíduos com perda à esquerda mostram mais dificuldade de fechamento, resolução e ordenação temporal.<br>PURPOSE: To assess the behaviors of temporal resolution and temporal ordering, sound localization, and auditory closure, and to investigate possible associations with complaints of learning, communication and language difficulties in individuals with unilateral hearing loss. METHODS: Participants were 26 individuals with ages between 8 and 15 years, divided into two groups: Unilateral hearing loss group; and Normal hearing group. Each group was composed of 13 individuals, matched by gender, age and educational level. All subjects were submitted to anamnesis, peripheral hearing evaluation, and auditory processing evaluation through behavioral tests of sound localization, sequential memory, Random Detection Gap test, and speech-in-noise test. Nonparametric statistical tests were used to compare the groups, considering the presence or absence of hearing loss and the ear with hearing loss. RESULTS: Unilateral hearing loss started during preschool, and had unknown or identified etiologies, such as meningitis, traumas or mumps. Most individuals reported delays in speech, language and learning developments, especially those with hearing loss in the right ear. The group with hearing loss had worse responses in the abilities of temporal ordering and resolution, sound localization and auditory closure. Individuals with hearing loss in the left ear showed worse results than those with hearing loss in the right ear in all abilities, except in sound localization. CONCLUSION: The presence of unilateral hearing loss causes sound localization, auditory closure, temporal ordering and temporal resolution difficulties. Individuals with unilateral hearing loss in the right ear have more complaints than those with unilateral hearing loss in the left ear. Individuals with hearing loss in the left ear have more difficulties in auditory closure, temporal resolution, and temporal ordering

INFLUENCE OF ACUTE SUPPLEMENTATION WITH MITOCHONDRIAL ANTIOXIDANT MITOQ ON VASCULAR FUNCTION IN HEALTHY ADULTS

Zach J. Hutchison, McKenna A. Tharpe, Alex M. Barnett, Braxton A. Linder, Meral N. Culver, Michael D. Brown, FACSM, Andreas N. Kavazis, FACSM, Austin T. Robinson. Auburn University, Auburn, AL. Background: Cardiovascular disease (CVD) is characterized by endothelial dysfunction and heightened oxidative stress. Additionally, there are well documented racial disparities in endothelial function and CVD. MitoQ, a mitochondrial specific antioxidant, improves vascular function in rodents and healthy older adults by scavenging excess reactive oxygen species (ROS). However, the role of MitoQ in attenuating racial disparities in vascular function is unknown. Therefore, as part of an ongoing clinical trial (NCT04334135), we evaluated endothelial function and ROS in healthy adults pre- and post-acute MitoQ (or placebo) supplementation and performed a preliminary racial comparison. Methods: Seventeen participants (eight males, age: 28±10 years, BMI 25±4 kg/m2, BP 110±12/66±6 mmHg, Mean±SD) were randomly assigned to placebo or MitoQ (100-160mg, depending on body mass). Participants reported as White, Black, or biracial based on parental race. Using a cross design, experimental sessions were separated by a ≥72-hour washout period. Measures were performed before and 60 minutes after ingestion of MitoQ or placebo capsules. We assessed brachial blood pressure (oscillometric) and brachial artery flow mediated dilation (FMD) via ultrasound. We placed an intravenous catheter to assess whole blood ROS levels via electronic paramagnetic resonance. To investigate treatment x time interactions, we performed 2-way ANOVA and ANCOVA. Results: Irrespective of treatment, systolic blood pressure decreased with time (p\u3c0.01). We did not find treatment x time interactions for brachial FMD % (pre placebo: 7.1±4% to post placebo: 6.4±4% vs pre MitoQ: 6.0±4% to post MitoQ: 6.9±4%, p=0.61), brachial shear stress area under the curve (AUC) during reactive hyperemia (p=0.30), or brachial FMD normalized to shear AUC (p=0.46). Additionally, there was not a treatment x time interaction for blood ROS (p=0.67). We identified a trend for a treatment x race interaction (p=0.058) for [post-pre] ∆FMD whereby MitoQ resulted in a negative ∆FMD only in White adults. However, when we included pre-treatment FMD as a covariate for ∆FMD, this trend was attenuated (p=0.193). Conclusion: While additional data are needed, our preliminary findings indicate that acute MitoQ supplementation does not influence vascular function or oxidative stress in healthy adults

ADJUSTING FOR EXERCISE INTENSITY ATTENUATES SEX DIFFERENCES IN BLOOD PRESSURE DURING EXERCISE IN HEALTHY ADULTS

McKenna A. Tharpe1, Joseph C. Watso2,3, Matthew C. Babcock4,3, Michael Brian5,3, Braxton A. Linder1, Kamila U. Pollin6,3, Zach J. Hutchison1, Alex M. Barnett1, William Farquhar, FACSM3, Austin T. Robinson1,3. 1Auburn University, Auburn, AL. 2University of Texas Southwest Medical Center, Dallas, TX. 3University of Delaware, Newark, DE. 4University of Colorado Denver, Aurora, CO. 5University of New Hampshire, Durham, NH. 6Veteran Affairs Medical Center, Washington, DC. PURPOSE: The exercise pressor reflex, composed of the muscle mechano- and metaboreflex, increases blood pressure (BP). Compared to males, healthy female adults typically exhibit blunted BP responses to exercise. However, recent work suggests that sex differences in BP during isometric handgrip (HG) exercise and post-exercise ischemia (PEI; metaboreflex isolation) are attenuated after adjusting for differences in maximal voluntary contraction (MVC). Therefore, the purpose of this study was to determine whether sex differences in BP responses during HG and PEI would be abolished after adjustment for submaximal HG squeezing force. METHODS: We analyzed data from 89 participants including 30 females (age: 24±4 years, BMI: 24±4 kg/m2, screening BP: 106±13/63±9 mmHg, Mean±SD) and 59 males (age: 24±4 years, BMI: 25±3 kg/m2, screening BP: 113±11/66±9 mmHg). All females were tested during days 1-5 of their menstrual cycle. Maximal HG force for each participant was defined as the average of three MVCs. Following a 10-minute baseline period, participants performed isometric static HG exercise at 40% of their average MVC for two minutes followed by three minutes of PEI via brachial artery occlusion. We obtained beat-to-beat BP readings via finger photoplethysmography (Finometer). Statistical analyses included t-tests, 2-way ANOVAs (sex x time) and ANCOVAs (average force during HG minute 2 as a covariate). RESULTS: Females exhibited a lower absolute 40% HG force than males (106±30 N v. 163±48 N, p=0.026). There was a significant sex x time interaction for peak (minute 2) ∆ systolic BP during HG (females: 19±12 mmHg v. 27±17 mmHg in males, p=0.022), but not diastolic (p=0.126) or mean BP (p=0.076). After adjusting for absolute HG force, the sex difference for ∆ systolic BP during HG was attenuated (p=0.095). Additionally, in a small strength-matched cohort (N=48, 28 females, female HG force mean = 106±26 N, male HG force mean = 120±25 N, p=0.078) there was not a significant sex difference for peak ∆ systolic BP during HG (p=0.200). During PEI there were sex x time interactions for systolic, diastolic, and mean BP (p\u3c0.01 for all) and adjustment for HG force did not attenuate these differences. CONCLUSION: Our data indicate that the sex difference in BP reactivity is attenuated after adjusting for absolute HG force during exercise, but not metaboreflex isolation