Comparing bullying to ACEs in the national survey of children's health: Examining 2016-2019 prevalence trends among children and adolescents.

OBJECTIVES: To estimate adverse childhood experience (ACE) prevalence among children and adolescents aged 6-17 years in the United States, to examine factors influencing the prevalence of ACEs over the time period 2016-2019, and to examine the difference in bullying trends compared to ACEs in the NSCH. PARTICIPANTS AND SETTING: The National Survey of Children's Health (NSCH) is a cross-sectional survey. Participants included respondents who completed the separate surveys for ages 6-11 and 12-17 from 2016 to 2019. METHODS: Cumulative ACEs were analyzed to determine the change in prevalence of having at least one ACE, overall and stratified by age group. RESULTS: Overall prevalence was highest among income difficulties (16-26 %); parent/guardian divorced or separated (29-31 %); and bullying (21-48 %). There was a significant time trend for income difficulties (decreased; p < 0.001), lived with anyone with a mental illness (increased; p = 0.004), racial/ethnic mistreatment (increased; p = 0.004), and bullying (increased; p < 0.001). Cumulative prevalence trends without bullying decreased significantly from 2016 to 2019 while prevalence trends for bullying increased significantly during this time frame. Sex, age, and race/ethnicity were significantly associated with some of the ACEs. CONCLUSIONS: Trend of ACEs varies as prevalence of some ACEs increased while decreasing for others over time. Also, ACEs appear to affect children and adolescents differently according to sex, age group, and racial/ethnic background, which warrants the need to prioritize efforts to decrease the exposure to ACEs.

A general class of small area estimation using calibrated hierarchical likelihood approach with applications to COVID-19 data.

The direct estimation techniques in small area estimation (SAE) models require sufficiently large sample sizes to provide accurate estimates. Hence, indirect model-based methodologies are developed to incorporate auxiliary information. The most commonly used SAE models, including the Fay-Herriot (FH) model and its extended models, are estimated using marginal likelihood estimation and the Bayesian methods, which rely heavily on the computationally intensive integration of likelihood function. In this article, we propose a Calibrated Hierarchical (CH) likelihood approach to obtain SAE through hierarchical estimation of fixed effects and random effects with the regression calibration method for bias correction. The latent random variables at the domain level are treated as 'parameters' and estimated jointly with other parameters of interest. Then the dispersion parameters are estimated iteratively based on the Laplace approximation of the profile likelihood. The proposed method avoids the intractable integration to estimate the marginal distribution. Hence, it can be applied to a wide class of distributions, including generalized linear mixed models, survival analysis, and joint modeling with distinct distributions. We demonstrate our method using an area-level analysis of publicly available count data from the novel coronavirus (COVID-19) positive cases.

Neurocognitive function and quality-of-life in patients with colorectal cancer.

OBJECTIVE: Colorectal cancer (CRC) survivors report significant long-term physical and cognitive declines post-treatment. Our purpose was to combine task-evoked Event-Related Potential (ERP) and resting state functional magnetic resonance imaging (rsf/MRI) methodologies to characterize the physiological underpinnings and cognitive sequelae of chemotherapy-related cognitive impairment, including changes in Quality-Of-Life (QOL) in patients with CRC, as compared to healthy control (HC) participants. METHODS: This descriptive study recruited and obtained baseline data from patients with CRC at medical and surgical oncology visits four to six weeks post-op and followed them at 12- and 24-weeks. Procedures employed ERP, pencil and paper neuropsychological testing (N-P), structural/functional rsf/MRI, and self-report QOL methodologies. Data analyses included correlations, one-way ANOVA, Chi-square tests, and linear mixed models. RESULTS: Study participants (n = 40) across groups (n = 15, 11, 14) were balanced on age, sex, education, and race, but not marital status Several significant associations were found between changes in Dorsal Attention Network (DAN)-related ERP measures (P2, N2, N2P2, N2pc amplitudes), with QOL measures between baseline and last visits (p < 0.05-0.001). Additionally, rsf/MRI findings showed increased network activity in a single node of the DAN post-treatment, which was associated with poorer performance on N-P tests of attention and working memory, as well as a focal decline in grey matter volume in the area. CONCLUSIONS: Our methodology revealed structural and functional changes within the DAN associated with altered spatial attention, working memory, and ability to inhibit. These disruptions may be responsible for decreased QOL ratings in patients with CRC. This study provides a putative mechanism of understanding how altered brain structural/functional relationships impact cognition, QOL, and nursing care in patients with CRC. NCI TRIAL ID: NCI-2020-05952, University of Nebraska Medical Center, Clinical Trials.gov ID NCT03683004.

Does the Heel's Dissipative Energetic Behavior Affect Its Thermodynamic Responses During Walking?

Most of the terrestrial legged locomotion gaits, like human walking, necessitate energy dissipation upon ground collision. In humans, the heel mostly performs net-negative work during collisions, and it is currently unclear how it dissipates that energy. Based on the laws of thermodynamics, one possibility is that the net-negative collision work may be dissipated as heat. If supported, such a finding would inform the thermoregulation capacity of human feet, which may have implications for understanding foot complications and tissue damage. Here, we examined the correlation between energy dissipation and thermal responses by experimentally increasing the heel's collisional forces. Twenty healthy young adults walked overground on force plates and for 10 min on a treadmill (both at 1.25 ms-1) while wearing a vest with three different levels of added mass (+0%, +15%, & +30% of their body mass). We estimated the heel's work using a unified deformable segment analysis during overground walking. We measured the heel's temperature immediately before and after each treadmill trial. We hypothesized that the heel's temperature and net-negative work would increase when walking with added mass, and the temperature change is correlated with the increased net-negative work. We found that walking with +30% added mass significantly increased the heel's temperature change by 0.72 ± 1.91   ℃ (p = 0.009) and the magnitude of net-negative work (extrapolated to 10 min of walking) by 326.94 ± 379.92 J (p = 0.005). However, we found no correlation between the heel's net-negative work and temperature changes (p = 0.277). While this result refuted our second hypothesis, our findings likely demonstrate the heel's dynamic thermoregulatory capacity. If all the negative work were dissipated as heat, we would expect excessive skin temperature elevation during prolonged walking, which may cause skin complications. Therefore, our results likely indicate that various heat dissipation mechanisms control the heel's thermodynamic responses, which may protect the health and integrity of the surrounding tissue. Also, our results indicate that additional mechanical factors, besides energy dissipation, explain the heel's temperature rise. Therefore, future experiments may explore alternative factors affecting thermodynamic responses, including mechanical (e.g., sound & shear-stress) and physiological mechanisms (e.g., sweating, local metabolic rate, & blood flow).

Step width variability as a discriminator of age-related gait changes.

BACKGROUND: There is scientific evidence that older adults aged 65 and over walk with increased step width variability which has been associated with risk of falling. However, there are presently no threshold levels that define the optimal reference range of step width variability. Thus, the purpose of our study was to estimate the optimal reference range for identifying older adults with normative and excessive step width variability. METHODS: We searched systematically the BMC, Cochrane Library, EBSCO, Frontiers, IEEE, PubMed, Scopus, SpringerLink, Web of Science, Wiley, and PROQUEST databases until September 2018, and included the studies that measured step width variability in both younger and older adults during walking at self-selected speed. Data were pooled in meta-analysis, and standardized mean differences (SMD) with 95% confidence intervals (CI) were calculated. A single-decision threshold method based on the Youden index, and a two-decision threshold method based on the uncertain interval method were used to identify the optimal threshold levels (PROSPERO registration: CRD42018107079). RESULTS: Ten studies were retrieved (older adults = 304; younger adults = 219). Step width variability was higher in older than in younger adults (SMD = 1.15, 95% CI = 0.60; 1.70; t = 4.72, p = 0.001). The single-decision method set the threshold level for excessive step width variability at 2.14 cm. For the two-decision method, step width variability values above the upper threshold level of 2.50 cm were considered excessive, while step width variability values below the lower threshold level of 1.97 cm were considered within the optimal reference range. CONCLUSION: Step width variability is higher in older adults than in younger adults, with step width variability values above the upper threshold level of 2.50 cm to be considered as excessive. This information could potentially impact rehabilitation technology design for devices targeting lateral stability during walking.

Neurophysiologic and ophthalmic markers of chemotherapy-related cognitive impairment in patients diagnosed with hematologic cancer: A feasibility study.

BACKGROUND: Biomarkers of chemotherapy-related cognitive impairment (CRCI) in hematologic cancer are understudied and underdeveloped. We evaluated the feasibility of using ophthalmic and neurophysiologic markers to assess CRCI in hematologic cancer. METHODS: Hematologic cancer patients either receiving (Ctx+) or not receiving (Ctx-) chemotherapy were recruited from a tertiary medical center. Demographically-matched healthy controls (HC) were also recruited. Ctx+ participants completed the following study visits: (1) after diagnosis but prior to chemotherapy (baseline); (2) after one treatment cycle (one-month post-baseline); and (3) after three treatment cycles (three-months post-baseline). Comparison subjects completed assessments at similar intervals. Participants completed: (1) neuropsychological assessments of attention and executive function; (2) neurophysiologic assessments of control over spatial attention and working memory; and (3) ophthalmic assessments of contrast sensitivity and optical coherence tomography (OCT). RESULTS: We enrolled 45 participants (15 per group), and 30 participants (Ctx+ = 8; Ctx- = 10; HC = 12) completed all study visits. Ctx+ participants performed worse than HC participants on neuropsychological measures of attention and executive function. Both Ctx+ and Ctx- participants showed changes in neurophysiologic measures of control over spatial attention that differed from HC participants. Ctx+ participants showed chemotherapy-related declines in contrast sensitivity that were predicted by OCT retinal nerve fiber layer thickness (RNFL) changes. Changes in neurophysiologic measures of control over spatial attention were also predicted by OCT RNFL changes. CONCLUSION: We demonstrated the feasibility of using ophthalmic and neurophysiologic markers as rapid and non-invasive measures that may be useful for tracking CRCI in hematologic cancer.

Strength of Plantar- and Dorsiflexors Mediates Step Regularity During a High Cognitive Load Situation in a Cross-sectional Cohort of Older and Younger Adults.

BACKGROUND AND PURPOSE: Completing simultaneous tasks while standing or walking (ie, a high cognitive load situation [HCLS]) is inevitable in daily activities and can lead to interference in task performances. Age-related physical and cognitive changes may confound performance variability during HCLS in older and younger adults. Identification of these confounding effects may reveal therapy targets to maintain optimal physical function later in life. The aim of this study was to investigate the effect of increasing the difficulty levels of an additional motor task and restricting visual information, on gait parameters in younger and older adults while considering the effect of cognitive and physical covariates. METHODS: Fifteen healthy younger and 14 healthy older adults were asked to complete assessments of cognitive function, balance, and strength. They were then asked to walk on a self-paced treadmill with or without carrying a plastic tray. Opaqueness of the tray (vision) and the presence of water in glasses placed on the tray (increasing task difficulty) were varied. Mean, standard deviation, and regularity (sample entropy) of step width and length were compared across conditions and groups using repeated-measures analyses of variance with and without covariate analysis. Only significantly correlated covariates of cognition, balance, and strength were entered into each model. RESULTS AND DISCUSSION: Older adults had greater step width irregularity compared with younger adults across all conditions when controlling for concentric plantar- and dorsiflexion strength. A decline in strength may likely alter neuromuscular control of gait, specifically control of step width, which has been associated with fall risk in older adults. Adjusting for the same covariates revealed increased regularity of step length, as visual feedback from the feet was restricted. Specifically, step length was more regular while carrying an opaque tray compared with not carrying a tray. Visual restriction was a contributing factor, which led to more predictable gait kinematics, indicating the role of sensory information to enhance the adaptability during walking under HCLS. CONCLUSION: The knowledge of the regularity behavior of human movement can expand physical therapists' treatment approaches to promote further interactivity and coordination across body systems that model behavior of healthy young individuals. Targeting strength during therapy may provide additional benefits for gait performance under HCLS.

Subjects With COPD Walk With Less Consistent Organization of Movement Patterns of the Lower Extremity.

BACKGROUND: The inherent stride-to-stride fluctuations during walking are altered in the aging population and could provide insight into gait impairments and falls in patients with COPD. Stride-to-stride fluctuations are quantified two ways: variability of the fluctuations (eg, standard deviation), and movement patterns within the fluctuations. Our objective was to investigate stride-to-stride fluctuations by evaluating the variability and movement patterns of lower limb joints in subjects with COPD compared to subjects without COPD as control subjects. METHODS: In this cross-sectional study, 22 subjects with COPD (age 63 ± 9 y; FEV1 54 ± 19% predicted) and 22 control subjects (age 62 ± 9 y; FEV1 95 ± 18% predicted) walked for 3 min on a treadmill while their gait was recorded. The amount of variability (ie, standard deviation and coefficient of variation) and movement patterns (ie, predictability and consistency in organization) were quantified for the range of motion and joint angle of the hip, knee, and ankle, at 3 walking speeds (ie, self-selected, fast, and slow). General linear mixed models were used for analysis. RESULTS: Control subjects had more consistent organization of the hip and knee joint movement patterns compared to subjects with COPD (P = .02 and P = .02, respectively). Further, control subjects adapted to speed changes by demonstrating more consistent organization of movement patterns with faster speeds, whereas subjects with COPD did not. At the fast walking speed, subjects with COPD demonstrated less consistent organization of knee and hip joint movement patterns as compared to control subjects without COPD (P = .03 and P = .005, respectively). The amount of variability did not differ between groups. CONCLUSIONS: Although subjects with COPD did not demonstrate decreased amount of variability, their hip and knee joint movement patterns were less consistent in organization during walking. Reduced consistency in organization of movement patterns may be a contributing factor to falls and mobility problems experienced by patients with COPD.

Using Tribal Data Linkages to Improve the Quality of American Indian Cancer Data in Michigan.

This study examines the extent to which data linkages between Indian Health Service, tribal data, and cancer registries affect cancer incidence rates among American Indians/Alaska Natives (AI/ANs) in Michigan. The incidence of tobacco- and alcohol-associated cancers for 1995-2012 was analyzed to compare rates of the Upper Peninsula (UP) and Lower Peninsula (LP) in Michigan and among AI/ANs and non-Hispanic Whites (NHWs). Complete linkage resulted in 1,352 additional AI/AN cases; 141 cases were linked via IHS records alone, while 373 were linked via tribal records alone; 838 were linked through both IHS and tribal records. Age-adjusted incidence rates for AI/ANs increased from 214.39 per 100,000 to 405.41 per 100,000, similar to that of NHWs after complete linkage (421.46 per 100,000). In the UP, AI/ANs had age-adjusted incidence rates 1.67 times higher than NHWs (596.69 per 100,000 vs. 356.32 per 100,000 respectively). This study indicates a substantial number of AI/AN cancer cases remain misclassified in Michigan.

Oxidative Stress Levels Throughout Pregnancy, at Birth, and in the Neonate.

BACKGROUND: Oxidative stress is associated with poor perinatal outcomes. Little is known regarding the longitudinal levels of oxidative stress in the perinatal period or the correlation between maternal and neonatal oxidative stress levels. OBJECTIVE: Describe and compare oxidative stress, specifically superoxide, superoxide dismutase, catalase, and glutathione levels, over the perinatal period. STUDY DESIGN: Longitudinal descriptive design using a convenience sample of medically high- and low-risk pregnant women (n = 140) from a maternal-fetal medicine and general obstetrics practice, respectively. Blood was obtained from women at 12-20 and 24-28 weeks' gestation and during labor, from the umbilical cord at birth, and from neonates at 24-72 hr after birth. Levels of superoxide were measured using electron paramagnetic resonance (EPR) spectroscopy; antioxidants (superoxide dismutase, catalase, and glutathione) were measured using commercial assay kits. Relationships between oxidative stress levels at different time points were examined using nonparametric methods. Pregnancy outcome was collected. RESULTS: Demographic variables, outcome variables, and oxidative stress levels in maternal blood, cord blood, and infants differed between medically high- and low-risk women. Descriptive patterns for oxidative stress measures varied over time and between risk groups. Significant correlations between time points were noted, suggesting intraindividual consistency may exist throughout the perinatal period. However, these correlations were not consistent across each medical risk group. CONCLUSION: EPR spectroscopy is a feasible method for the perinatal population. Results provide new information on perinatal circulating superoxide levels and warrant further investigation into potential relationships between prenatal and neonatal physiologic dysregulation of oxidative stress.

Impact of Initiating Screening Programs on Referral and Management of Cervical Cancer in Tanzania.

PURPOSE: We investigated the impact of screening rural patients on referral and management of cervical cancer in Tanzania. METHODS: After reviewing more than 10,000 medical records of patients with cervical cancer who visited Ocean Road Cancer Institute (ORCI) from 2005 to 2014, 108 patients were from the rural communities of Bagamoyo and Chalinze. We abstracted demographic, clinical, and lifestyle factors and linked the data set to databases of all 1,151 patients who visited the Bagamoyo screening clinic from 2011 to 2014 and 1,273 patients who visited the Chalinze screening clinic from 2012 to 2014. RESULTS: After initiation of the rural screening clinics, difference in duration from diagnosis to prescribed treatment increased from 50.5 to 88 days (P = .030), and duration from referral to treatment increased from 38.6 to 101.3 days (P = .041). Proportion of patients who received combination chemoradiotherapy increased from 34.3% to 69% (P = .001) and completion of treatment decreased from 94.4% to 72.41% (P = .002) after initiation of the ORCI screening clinic. Patients who visited Muhimbili National Hospital had significantly shorter periods between referral and prescribed treatment than patients who did not use the Muhimbili National Hospital (mean ± standard deviation, 49.4 ± 128.8 and 112.1 ± 195.31 days, respectively; P = .010). Patients who were treated at ORCI had significantly shorter periods between diagnosis and referral to treatment (mean ± standard deviation, 31.4 ± 62.35 and 36.4 ± 121.79 days, respectively; P = .005). CONCLUSION: Future research should focus on investigating barriers to seeking cancer care, benefits of chemoradiotherapy in this population considering the change in prescribed treatment, and time until diagnosis and treatment. Prescription of complex treatments that require more visits to treatment centers may also contribute to decline in completion of treatment.

Patterns of occurrence and implications of neratinib-associated diarrhea in patients with HER2-positive breast cancer: analyses from the randomized phase III ExteNET trial.

BACKGROUND: We characterized patterns of occurrence and the impact of neratinib-associated diarrhea in the absence of protocol-directed antidiarrheal prophylaxis or a formal diarrhea management plan using data from Extended Adjuvant Treatment of Breast Cancer with Neratinib (ExteNET). METHODS: ExteNET is a multicenter, double-blind, placebo-controlled, randomized phase III trial involving community-based and academic institutions in 40 countries. Women with HER2-positive early-stage breast cancer with prior standard primary therapy and trastuzumab-based (neo)adjuvant therapy were randomized to neratinib 240 mg/day or placebo for 12 months. Safety, a secondary outcome, was assessed using the National Cancer Institute Common Terminology Criteria version 3.0. Health-related quality of life by diarrhea grade was assessed using Functional Assessment of Cancer Therapy-Breast (FACT-B). RESULTS: Two thousand eight hundred sixteen women (1408 per group) were safety-evaluable. Grade 3 and 4 diarrhea occurred in 561 (39.8%) and 1 (0.1%) patients with neratinib versus 23 (1.6%) and 0 patients with placebo, respectively. In the neratinib group, 28.6% of patients had grade 3 events during month 1 decreasing to ≤ 6% after month 3. The median cumulative duration of grade 3/4 diarrhea with neratinib was 5 days (interquartile range, 2-9). Serious diarrheal events (n = 22, 1.6%) and diarrheal events requiring hospitalization (n = 20, 1.4%) were rare with neratinib. Changes in FACT-B total score by diarrhea grade in the neratinib group did not meet the threshold for clinically important differences. CONCLUSIONS: In the absence of antidiarrheal prophylaxis, neratinib-related diarrhea is short-lived and not associated with complications or long-term sequelae. This suggests that targeted preventive management with antidiarrheal prophylaxis early during neratinib treatment is appropriate. TRIAL REGISTRATION: ClinicalTrials.gov NCT00878709. Registered 9 April 2009.

Gait Mechanics Differences Between Healthy Controls and Patients With Peripheral Artery Disease After Adjusting for Gait Velocity Stride Length and Step Width.

Patients with peripheral artery disease (PAD) experience significant leg dysfunction. The effects of PAD on gait include shortened steps, slower walking velocity, and altered gait kinematics and kinetics, which may confound joint torques and power measurements. Spatiotemporal parameters, joint torques and powers were calculated and compared between 20 patients with PAD and 20 healthy controls using independent t-tests. Separate ANCOVA models were used to evaluate group differences after independently adjusting for gait velocity, stride length and step width. Compared to healthy controls, patients with PAD exhibited reduced peak extensor and flexor torques at the knee, and hip. After adjusting for all covariates combined, differences between groups remained for ankle power generation in late stance, and knee flexor torque. Reduced walking velocity observed in subjects affected by PAD was closely connected with reductions in joint torques and powers during gait. Gait differences remained, at the knee and ankle, after adjusting for the combined effect of spatiotemporal parameters. Improving muscle function through exercise or with the use of assistive devices needs to be a key tool in the development of interventions that aim to enhance the ability of PAD patients to restore spatiotemporal gait parameters.

U.S. Medical Examiner/Coroner capability to handle highly infectious decedents.

In the United States of America, Medical Examiners and Coroners (ME/Cs) investigate approximately 20% of all deaths. Unexpected deaths, such as those occurring due to a deceased person under investigation for a highly infectious disease, are likely to fall under ME/C jurisdiction, thereby placing the ME/C and other morgue personnel at increased risk of contracting an occupationally acquired infection. This survey of U.S. ME/Cs' capabilities to address highly infectious decedents aimed to determine opportunities for improvement at ME/C facilities serving a state or metropolitan area. Data for this study was gathered via an electronic survey. Of the 177 electronic surveys that were distributed, the overall response rate was N = 108 (61%), with 99 of those 108 respondents completing all the questions within the survey. At least one ME/C responded from 47 of 50 states, and the District of Columbia. Select results were: less than half of respondents (44%) stated that their office had been involved in handling a suspected or confirmed highly infectious remains case and responses indicated medical examiners. Additionally, ME/C altered their personal protective equipment based on suspected versus confirmed highly infectious remains rather than taking an all-hazards approach. Standard operating procedures or guidelines should be updated to take an all-hazards approach, best-practices on handling highly infectious remains could be integrated into a standardized education, and evidence-based information on appropriate personal protective equipment selection could be incorporated into a widely disseminated learning module for addressing suspected or confirmed highly infectious remains, as those areas were revealed to be currently lacking.

Energy efficient physiologic coupling of gait and respiration is altered in chronic obstructive pulmonary disease.

AIMS: Coupling between walking and breathing in humans is well established. In healthy systems, the ability to couple and uncouple leads to energy economization. It is unknown if physiologic efficiency is susceptible to alteration, particularly in individuals with airflow obstruction. The aim of this research was to determine if coupling was compromised in a disease characterized by abnormal airflow and dyspnoea, and if this was associated with reduced energy efficiency. METHODS: As a model of airflow obstruction, 17 chronic obstructive pulmonary disease (COPD) patients and 23 control subjects were included and walked on a treadmill for 6 minutes at three speeds (preferred speed and ±20% preferred speed) while energy expenditure, breathing, and walking were recorded. Rating of perceived exertion was recorded at the end of each walking trial. The most commonly used frequency ratio (ie, strides:breath) and cross recurrence quantification analysis were used to quantify coupling. Linear regression models were used to determine associations. RESULTS: Less complex frequency ratios, simpler ratios, (ie, 1:1 and 3:2) accompanied with stronger coupling were moderately associated with increased energy expenditure in COPD subjects. This was found for all three speeds. CONCLUSION: The novel finding was that increased energy expenditure was associated with stronger and less complex coupling. Increased effort is needed when utilizing a frequency ratio of 1:1 or 3:2. The more stable the coupling, the more effort it takes to walk. In contrast to the complex energy efficient coupling of controls, those with airflow obstruction manifested simpler and stronger coupling associated with reduced energy efficiency.

Stride-time variability is related to sensorimotor cortical activation during forward and backward walking.

Previous research has used functional near-infrared spectroscopy (fNIRS) to show that motor areas of the cortex are activated more while walking backward compared to walking forward. It is also known that head movement creates motion artifacts in fNIRS data. The aim of this study was to investigate cortical activation during forward and backward walking, while also measuring head movement. We hypothesized that greater activation in motor areas while walking backward would be concurrent with increased head movement. Participants performed forward and backward walking on a treadmill. Participants wore motion capture markers on their head to quantify head movement and pressure sensors on their feet to calculate stride-time. fNIRS was placed over motor areas of the cortex to measure cortical activation. Measurements were compared for forward and backward walking conditions. No significant differences in body movement or head movement were observed between forward and backward walking conditions, suggesting that conditional differences in movement did not influence fNIRS results. Stride-time was significantly shorter during backward walking than during forward walking, but not more variable. There were no differences in activation for motor areas of the cortex when outliers were removed. However, there was a positive correlation between stride-time variability and activation in the primary motor cortex. This positive correlation between motor cortex activation and stride-time variability suggests that forward walking variability may be represented in the primary motor cortex.

When Coordinating Finger Tapping to a Variable Beat the Variability Scaling Structure of the Movement and the Cortical BOLD Signal are Both Entrained to the Auditory Stimuli.

Rhythmic actions are characterizable as a repeating invariant pattern of movement together with variability taking the form of cycle-to-cycle fluctuations. Variability in behavioral measures is atypically random, and often exhibits serial temporal dependencies and statistical self-similarity in the scaling of variability magnitudes across timescales. Self-similar (i.e. fractal) variability scaling is evident in measures of both brain and behavior. Variability scaling structure can be quantified via the scaling exponent (α) from detrended fluctuation analysis (DFA). Here we study the task of coordinating thumb-finger tapping to the beats of constructed auditory stimuli. We test the hypothesis that variability scaling evident in tap-to-tap intervals as well as in the fluctuations of cortical hemodynamics will become entrained to (i.e. drawn toward) manipulated changes in the variability scaling of a stimulus's beat-to-beat intervals. Consistent with this hypothesis, manipulated changes of the exponent α of the experimental stimuli produced corresponding changes in the exponent α of both tap-to-tap intervals and cortical hemodynamics. The changes in hemodynamics were observed in both motor and sensorimotor cortical areas in the contralateral hemisphere. These results were observed only for the longer timescales of the detrended fluctuation analysis used to measure the exponent α. These findings suggest that complex auditory stimuli engage both brain and behavior at the level of variability scaling structures.

Video Head Impulse Test (vHIT): The Role of Corrective Saccades in Identifying Patients With Vestibular Loss.

OBJECTIVE: 1) Characterize corrective saccades (CS) in normal controls, and 2) examine the sensitivity of the video head impulse test (vHIT) for identifying vestibular loss using both gain and CS. STUDY DESIGN: Prospective combined with retrospective review. SETTING: Tertiary referral center. PATIENTS: Seventy subjects with normal vestibular function served as controls (mean age, 44.1 yr; range, 10-78) and data from 49 patients with unilateral and bilateral vestibular loss was retrospectively reviewed (mean age, 50; range, 7-81). INTERVENTION: vHIT; individual horizontal head impulses were then analyzed in MATLAB. MAIN OUTCOME MEASURES: Horizontal vHIT gain, CS peak velocity, frequency, and latency. RESULTS: There was not an age effect for CS velocity or latency, and only a weak relationship between CS frequency and age in the control group. Gain and CS latency were the only parameters affected by impulse side, demonstrating higher gain and longer latency on the right. The group with vestibular loss had significantly lower mean vHIT gain, higher mean CS frequency, higher mean CS velocity, earlier CS latency, and smaller mean CS standard deviations of the latency compared with the control group.When all factors were analyzed separately by logistic regression, vHIT gain provided the best classification (83.8%), closely followed by CS frequency (83.1%). Using a two variable approach (both gain and CS frequency) yielded the best diagnostic accuracy (overall classification = 84.6%). CONCLUSIONS: Along with gain, incorporating CS frequency in interpreting vHIT improves diagnostic accuracy. A repeatable CS (>81.89%) and/or low gain (<0.78) indicate vestibular loss.

Predictive Factors for Vestibular Loss in Children With Hearing Loss.

PURPOSE: The aim of this study was to determine if there are factors that can predict whether a child with hearing loss will also have vestibular loss. METHOD: A retrospective chart review was completed on 186 children with hearing loss seen at Boys Town National Research Hospital for vestibular testing from 1999 to 2015 through neurosensory genetics clinic or cochlear implant candidacy. Each child's medical chart was reviewed to obtain the following data: vestibular loss severity (classified as normal, bilateral, or mild to moderate), degree of hearing loss (bilateral pure-tone average [PTA]), imaging abnormalities (classified as "normal" or "abnormal"), parental concerns for gross motor delay (classified as "yes, there is concern" or "no, there is not a concern"), parent report of age when their child sat (months) and walked independently (months), comorbidities (classified as "yes" if there were 1 or more comorbidities or "no" if there were no comorbidities), and score on the Developmental Profile-3. RESULTS: Children were grouped according to vestibular loss severity; 115 children had normal vestibular function, 31 had bilateral vestibular loss, and 40 had mild-to-moderate vestibular loss. As severity of vestibular loss increased, children (a) sat and walked later, (b) scored more poorly on the Developmental Profile-3 physical subscale, (c) had more severe hearing loss, (d) had parents who more frequently reported concern for gross motor delay, and (e) were more likely to have other comorbidities. Of these factors, age-to-sit, age-to-walk, PTA, and parental concerns for gross motor developmental delay had the greatest ability to differentiate children with vestibular loss from children with normal vestibular function. For age-to-sit, using a cutoff value of 7.25 months yielded a sensitivity of 62% and a specificity of 81%. For age-to-walk, a cutoff value of 14.5 months yielded a sensitivity of 78% and a specificity of 77%. For PTA for the neurosensory genetics group, a cutoff value of 40 dB yielded a sensitivity of 80% and a specificity of 55%; however, a cutoff value of 66 dB yielded a sensitivity of 33% and an improved specificity of 91%. CONCLUSIONS: A referral for vestibular evaluation should be considered for children whose hearing loss is greater than 66 dB and particularly those who sit later than 7.25 months or walk later than 14.5 months or whose parents report concerns for gross motor development. Collectively, these factors appear to be more sensitive for identifying children with bilateral vestibular loss compared with children with mild-to-moderate vestibular loss. Because of the benefit of physical therapy, children identified with vestibular loss should then be referred to physical therapy for further evaluation and treatment.

Effect of parameter selection on entropy calculation for long walking trials.

It is sometimes difficult to obtain uninterrupted data sets that are long enough to perform nonlinear analysis, especially in pathological populations. It is currently unclear as to how many data points are needed for reliable entropy analysis. The aims of this study were to determine the effect of changing parameter values of m, r, and N on entropy calculations for long gait data sets using two different modes of walking (i.e., overground versus treadmill). Fourteen young adults walked overground and on a treadmill at their preferred walking speed for one-hour while step time was collected via heel switches. Approximate (ApEn) and sample entropy (SampEn) were calculated using multiple parameter combinations of m, N, and r. Further, r was tested under two cases r*standard deviation and r constant. ApEn differed depending on the combination of r, m, and N. ApEn demonstrated relative consistency except when m=2 and the smallest r values used (rSD=0.015*SD, 0.20*SD; rConstant=0 and 0.003). For SampEn, as r increased, SampEn decreased. When r was constant, SampEn demonstrated excellent relative consistency for all combinations of r, m, and N. When r constant was used, overground walking was more regular than treadmill. However, treadmill walking was found to be more regular when using rSD for both ApEn and SampEn. For greatest relative consistency of step time data, it was best to use a constant r value and SampEn. When using entropy, several r values must be examined and reported to ensure that results are not an artifact of parameter choice.