No Effect of Scapular Position on 3-Dimensional Scapular Motion in the Throwing Shoulder of Healthy Professional Pitchers

2012 ◽  
Vol 21 (2) ◽  
pp. 186-193 ◽  
Author(s):  
Amee L. Seitz ◽  
Michael Reinold ◽  
Robert A. Schneider ◽  
Thomas J. Gill ◽  
Charles Thigpen
Keyword(s):  
Mixed Model ◽  
Outcome Measure ◽  
External Rotation ◽  
Tracking System ◽  
Cross Sectional Study ◽  
Cross Sectional ◽  
Main Outcome Measure ◽  
3 Dimensional ◽  
Baseball Pitchers ◽  
Scapular Motion

Context:Differences in 3-dimensional (3D) scapular motion have been reported between healthy baseball position players and healthy nonoverhead athletic controls, as well as players diagnosed with shoulder impingement syndrome. These alterations are theorized to be the result of adaptations due to the demands of repetitive throwing. However, comparisons between the throwing and nonthrowing shoulders are commonly used to infer normal motion.Objective:The purpose of this study was to compare 3D scapular kinematics between the throwing and nonthrowing shoulders in asymptomatic professional male baseball pitchers.Design:Cross-sectional study.Setting:Laboratory.Participants:45 asymptomatic professional baseball pitchers participating without restrictions during preseason training.Interventions:An electromagnetic tracking system was used to assess 3D scapular orientation at rest and during weighted (2.3-kg) shoulder flexion across discrete humeral-flexion angles (rest, 30°, 60°, 90°, 120°, and maximum).Main Outcome Measure:3D scapular upward/downward rotation (UR/DR), anteroposterior (AP) tilt, and internal/external rotation (IR/ER). Separate mixed-model ANOVAs (Side × Angle) for each scapular motion were used to compare the throwing and the nonthrowing shoulder across all angles.Results:There were significant side-to-side differences with scapular UR/DR (P < .001), AP tilt (P < .001), and IR/ER (P < .001). The throwing scapula displayed greater mean UR (increase = 3.6°, SE = 0.50) and anterior/posterior tilt (increase = 2.1°, SE = 0.60) and less mean IR (decrease = 2.1°, SE = 0.66) than the nonthrowing shoulder averaged across all arm angles.Conclusions:In asymptomatic professional pitchers, the throwing shoulder’s scapular position differs across all arm angles from that of the nonthrowing shoulder, but the motion does not differ. Scapular asymmetry that is consistent throughout arm elevation may be indicative not of pathology but, potentially, of a normal adaptation of the pitching shoulder.

The Association Between Hands-On Instruction and Proper Child Safety Seat Installation

PEDIATRICS ◽  
2000 ◽  
Vol 106 (Supplement_3) ◽  
pp. 924-929
Author(s):  
Wendy G. Lane ◽  
Gilbert C. Liu ◽  
Elizabeth Newlin
Keyword(s):  
Primary Care ◽  
Outcome Measure ◽  
Private Insurance ◽  
Cross Sectional Study ◽  
Child Safety ◽  
Sectional Study ◽  
Cross Sectional ◽  
Main Outcome Measure ◽  
Hands On ◽  
Safety Seat

Objective. To determine if hands-on instruction in child safety seat (CSS) installation decreases the number of errors in installation. Design. Cross-sectional study. Setting. Primary care offices, emergency department, CSS checkpoint. Participants. Parents of children &lt;2 years old receiving medical care or attending a CSS check. Main Outcome Measure. Errors in CSS use. Results. Only 6.4% of parents had a correctly installed CSS. Hands-on instruction was associated with fewer errors in seat installation. Increased parent age, completion of college, and having private insurance were also associated with fewer errors in CSS placement. The majority of parents learned to install seats from reading the manual, from friends and relatives, and from figuring it out on their own. Conclusions. Errors in CSS installation are a significant problem. Hands-on instruction decreases the numbers of errors in CSS installation. However, few parents receive hands-on instruction from experts in CSS installation. Increases in correct CSS use could result from hands-on education by trained professionals.

scholarly journals Temperature Increases in the Human Achilles Tendon During Ultrasound Treatments With Commercial Ultrasound Gel and Full-Thickness and Half-Thickness Gel Pads

2010 ◽  
Vol 45 (4) ◽  
pp. 333-337 ◽  
Author(s):  
David O. Draper ◽  
Clinton G. Edvalson ◽  
Kenneth L. Knight ◽  
Dennis Eggett ◽  
Joseph Shurtz
Keyword(s):  
Achilles Tendon ◽  
Outcome Measure ◽  
Cross Sectional Study ◽  
Triceps Surae ◽  
Therapeutic Modality ◽  
Sectional Study ◽  
Cross Sectional ◽  
Main Outcome Measure ◽  
Internal Structures ◽  
Half Thickness

Abstract Context: Although originally manufactured for use in diagnostic imaging of internal structures, 2-cm-thick gel pads are also used as conducting media for therapeutic ultrasound over areas with bony prominences. Research on the ability of these pads to conduct enough energy to adequately heat tissues has provided mixed results. However, this research has mainly been performed on the triceps surae muscle, an area over which gel pads are not typically used. We wondered how much heating might be produced if a thinner pad was used over a tendon. Objective: To compare temperature rises in the human Achilles tendon during ultrasound treatments using ultrasound gel, a 2-cm-thick pad, and a 1-cm-thick pad. Design: Cross-sectional study. Setting: University therapeutic modality laboratory. Patients or Other Participants: Forty-eight healthy volunteers (24 women, 24 men). Intervention(s): We inserted a rigid thermocouple 1 cm deep into the Achilles tendon. Ultrasound was delivered at the following settings: 3 MHz, continuous, 1 W/cm2, 10 minutes. Main Outcome Measure(s): Temperature was recorded every 30 seconds for 10 minutes. Results: Temperature increased the most in the ultrasound gel group (increase  =  13.3°C, peak  =  42°C). The 1-cm-thick pad resulted in higher tendon temperature (increase  =  9.3°C, peak  =  37.8°C) than the 2-cm-thick pad (increase  =  6.5°C, peak  =  4.8°C). The 1-cm pad produced approximately 30% more heating than the 2-cm pad (SE  =  0.72, P &lt; .03). Conclusions: The thinner pad transmitted ultrasound more efficiently than the thicker pad. Thus, a gel pad of less than 1-cm thickness might be useful for superficial areas, such as the hands and ankles.

scholarly journals Strength Profiles of Shoulder Rotators in Healthy Sport Climbers and Nonclimbers

2009 ◽  
Vol 44 (5) ◽  
pp. 527-530 ◽  
Author(s):  
Emmy K. L. Wong ◽  
Gabriel Y. F. Ng
Keyword(s):  
Outcome Measure ◽  
External Rotation ◽  
Cross Sectional Study ◽  
Science Laboratory ◽  
Exercise Science ◽  
Cross Sectional ◽  
The Difference ◽  
Strength Difference ◽  
Induced Changes ◽  
Eccentric Work

Abstract Objective: To establish the isokinetic strength profiles and work ratios of the shoulder internal and external rotators in sport climbers and to compare them with these profiles and ratios in nonclimbers. We hypothesized that the strength profiles of the shoulder rotators were different between sport climbers and nonclimbers. Design: Cross-sectional study. Setting: Exercise science laboratory. Patients or Other Participants: Thirty-one experienced sport climbers and 27 nonclimbers. Main Outcome Measure(s): We tested all participants by measuring the isokinetic concentric and eccentric work output of their shoulder rotators in the middle 110° of shoulder rotation. We measured mean conventional work ratios of concentric external rotation (ER) to internal rotation (IR) (con ER:IR) and eccentric ER to IR (ecc ER:IR), and we measured mean functional work ratios of eccentric ER to concentric IR (ecc ER:con IR) and eccentric IR to concentric ER (ecc IR:con ER). Results: All work ratios were different between the 2 groups (P &lt; .001). In the climbers, the conventional work ratios were smaller than 1 for con ER:IR (0.79) and ecc ER:IR (0.88), whereas for the nonclimbers, the ratios were 1.03 and 1.13, respectively. The functional work ratio of ecc ER:con IR was smaller for the climbers (1.05) than for the nonclimbers (1.30), but the functional work ratio of ecc IR:con ER was larger for the climbers (1.58) than for the nonclimbers (1.17). Conclusions: The difference in work ratios of the shoulder rotators between participant groups might be due to training-induced changes in the shoulder rotation muscles of sport climbers. The clinical implication of this strength difference in shoulder IR and ER in climbers has yet to be examined.

Isokinetic Rotator Cuff Functional Ratios and the Development of Shoulder Injury in Collegiate Baseball Pitchers

2015 ◽  
Vol 20 (3) ◽  
pp. 46-52 ◽  
Author(s):  
Rachele E. Vogelpohl ◽  
Roger O. Kollock
Keyword(s):  
Rotator Cuff ◽  
Human Performance ◽  
Outcome Measure ◽  
External Rotation ◽  
Peak Torque ◽  
Shoulder Injury ◽  
Acceleration Phase ◽  
Main Outcome Measure ◽  
Collegiate Baseball ◽  
Baseball Pitchers

Context:Shoulder injury in baseball pitchers is a very common problem and has been linked to an imbalance in rotator cuff strength. Recently, the use of functional shoulder strength ratios has become more popular because they more closely resemble the actions of the shoulder during the throwing motion.Objective:To investigate the link between preseason shoulder rotator cuff functional strength ratios and the development of shoulder pain and injury.Design:Prospective research design.Setting:University human performance laboratory.Patients:Fifteen collegiate baseball pitchers participated in this study. At the end of the baseball season, six (19.5 ± 1.8 years, 73.6 ± 2.8 inches, 198.7 ± 19.1 lbs) developed shoulder injury and were placed in the injured group, and nine (21.0 ± 1.7 years, 73.1 ± 2.3 inches, 207.9 ± 28.1 lbs) did not develop injury and were placed in the noninjured group.Interventions:Isokinetic peak torque was collected concentrically and eccentrically for both shoulder internal rotation (IR) and external rotation (ER) at 60°-s−1, 180°-s−1, and 300°-s−1.Main Outcome Measure:The following functional ratios were calculated from the peak torque measures: concentric ER: concentric IR; eccentric ER: eccentric IR; concentric ER: eccentric IR (cocking phase); and eccentric ER: concentric IR (acceleration phase). Analysis was conducted using an analysis of variance comparing the injured and noninjured groups. A secondary analysis was conducted using an analyses of variance on the concentric and eccentric peak torque for shoulder IR and ER between groups.Results:The acceleration phase functional shoulder ratio was significantly higher (p = .019) in the injured group and a concentric IR peak torque (p = .003) was significantly lower in the injured group compared with the noninjured group.conclusion:Increased acceleration phase ratios and decreased concentric IR peak torque may be linked to the development of shoulder injury during a baseball season.

scholarly journals Intended Hydration Strategies and Knowledge of Exercise-Associated Hyponatraemia in Marathon Runners: A Questionnaire-Based Study

2018 ◽  
Vol 53 (7) ◽  
pp. 696-702 ◽  
Author(s):  
Thomas Leggett ◽  
Jonathan Williams ◽  
Colm Daly ◽  
Courtney Kipps ◽  
Richard Twycross-Lewis
Keyword(s):  
Fluid Intake ◽  
Outcome Measure ◽  
Nonparametric Methods ◽  
Cross Sectional Study ◽  
Sources Of Information ◽  
Sectional Study ◽  
Cross Sectional ◽  
Marathon Runners ◽  
Main Outcome Measure ◽  
Lack Of Knowledge

Context:  Exercise-associated hyponatremia (EAH) is a potentially fatal condition that can be prevented by avoiding excessive fluid intake. Running has become more popular in recent years, so it is important to assess the safety of runners' hydration strategies. Objective:  (1) To explore the intended hydration strategies of a sample of marathon runners before the 2014 London Marathon, (2) to examine their sources of information and knowledge about fluid intake and their understanding of EAH, and (3) to compare these findings with the results of a similar study carried out before the 2010 London Marathon. Design:  Cross-sectional study. Setting:  The 2014 London Marathon. Patients or Other Participants:  A total of 298 runners (148 males, 150 females), 0.83% of all race finishers. Main Outcome Measure(s):  Planned frequency, type, and volume of hydration; sources of information about appropriate drinking; and understanding of hyponatremia were explored. Comparisons were made with data collected from a sample of participants at the 2010 London Marathon. Data relating to the 2014 cohort are presented in descriptive form. Comparisons of the 2010 and 2014 cohorts were conducted using parametric and nonparametric methods. Results:  A total of 48.7% of the 2014 cohort listed drinking to thirst as the most important factor affecting their hydration strategy during the race. This compared with 25.3% of runners from the 2010 cohort and represented an increase (χ2 = 29.1, P = .001); 5.8% of the 2014 cohort planned on drinking more than 3.5 L, compared with 12% of the 2010 cohort (χ2 = 4.310, P = .038). Conclusions:  The number of sampled individuals using thirst to guide hydration strategies in the 2014 London Marathon increased from 2010. However, more than half of the 2014 cohort was not planning to drink to thirst. Runners still need to be educated about the risks of overdrinking as they continue to demonstrate a lack of knowledge and understanding.

scholarly journals Pitch Volume and Glenohumeral and Hip Motion and Strength in Youth Baseball Pitchers

2018 ◽  
Vol 53 (1) ◽  
pp. 60-65 ◽  
Author(s):  
Josie L. Harding ◽  
Kelsey J. Picha ◽  
Kellie C. Huxel Bliven
Keyword(s):  
Injury Risk ◽  
External Rotation ◽  
Cross Sectional Study ◽  
Hip Joints ◽  
Cross Sectional ◽  
Hip Range Of Motion ◽  
Youth Baseball ◽  
Hip Motion ◽  
Baseball Pitchers ◽  
Increased Strength

Context:  Increased pitch volume and altered glenohumeral (GH) and hip range of motion (ROM) and strength contribute to injury risk in baseball pitchers. Although these factors affect one another, whether they are related is unknown. Objective:  To examine relationships among cumulative and seasonal pitch volume, ROM, and strength of the GH and hip joints in youth baseball pitchers. Design:  Cross-sectional study. Setting:  Baseball practice facilities. Patients or Other Participants:  A total of 28 healthy baseball pitchers (age = 13.9 ± 2.9 years). Main Outcome Measure(s):  A demographic and pitching questionnaire was used to quantify pitch volume. Glenohumeral internal-rotation (IR) and external-rotation (ER) ROM and strength of the throwing arm; total arc of motion (IR + ER ROM); and bilateral hip IR, ER, and total arc of motion ROM and strength in IR, ER, and abduction were measured. A goniometer was used to assess ROM; a handheld dynamometer, to assess strength. Frequency analyses and bivariate correlations (age covariate) described data and identified relationships. Results:  Correlations between years of competitive play and increased strength in lead-leg hip IR (r = 0.52, P = .02) and abduction (r = 0.48, P = .04) and stance-leg hip IR (r = 0.45, P = .05) were fair to good. The number of months played in the last year had a fair correlation with decreased GH IR strength (r = −0.39, P = .04) and increased stance-leg hip IR strength (r = 0.44, P = .05). Limited pitch time had a fair correlation with increased GH ER ROM (r = 0.40, P = .04) and an excellent correlation with increased lead-leg hip IR ROM (r = 0.79, P &lt; .001). Increased innings pitched per game had a fair to good correlation with decreased GH IR strength (r = −0.41, P = .04) and stance-leg hip ER ROM (r = −0.53, P = .03). More pitches per game had a fair to good correlation with increased GH ER ROM (r = 0.44, P = .05) and decreased stance-leg hip ER ROM (r = −0.62, P = .008). Conclusions:  The significant relationships identified in this study suggest the need to further examine youth and adolescent cumulative and seasonal pitch guidelines.

Head Impact Biomechanics in Youth Flag Football: A Prospective Cohort Study

2021 ◽  
pp. 036354652110266
Author(s):  
Landon B. Lempke ◽  
Rachel S. Johnson ◽  
Rachel K. Le ◽  
Melissa N. Anderson ◽  
Julianne D. Schmidt ◽  
...  
Keyword(s):  
Mixed Model ◽  
Linear Acceleration ◽  
Cross Sectional Study ◽  
Head Impact ◽  
Rotational Acceleration ◽  
Event Type ◽  
Level Of Evidence ◽  
Cross Sectional ◽  
Head Impact Biomechanics ◽  
Impact Biomechanics

Background: Youth flag football participation has rapidly grown and is a potentially safer alternative to tackle football. However, limited research has quantitatively assessed youth flag football head impact biomechanics. Purpose: To describe head impact biomechanics outcomes in youth flag football and explore factors associated with head impact magnitudes. Study Design: Cross-sectional study; Level of evidence, 3. Methods: We monitored 52 player-seasons among 48 male flag football players (mean ± SD; age, 9.4 ± 1.1 years; height, 138.6 ± 9.5 cm; mass, 34.7 ± 9.2 kg) across 3 seasons using head impact sensors during practices and games. Sensors recorded head impact frequencies, peak linear ( g) and rotational (rad/s2) acceleration, and estimated impact location. Impact rates (IRs) were calculated as 1 impact per 10 player-exposures; IR ratios (IRRs) were used to compare season, event type, and age group IRs; and 95% CIs were calculated for IRs and IRRs. Weekly and seasonal cumulative head impact frequencies and magnitudes were calculated. Mixed-model regression models examined the association between player characteristics, event type, and seasons and peak linear and rotational accelerations. Results: A total of 429 head impacts from 604 exposures occurred across the study period (IR, 7.10; 95% CI, 4.81-10.50). Weekly and seasonal cumulative median head impact frequencies were 1.00 (range, 0-2.63) and 7.50 (range, 0-21.00), respectively. The most frequent estimated head impact locations were the skull base (n = 96; 22.4%), top of the head (n = 74; 17.2%), and back of the head (n = 66; 15.4%). The combined event type IRs differed among the 3 seasons (IRR range, 1.45-2.68). Games produced greater IRs (IRR, 1.24; 95% CI, 1.01-1.53) and peak linear acceleration (mean difference, 5.69 g; P = .008) than did practices. Older players demonstrated greater combined event–type IRs (IRR, 1.46; 95% CI, 1.12-1.90) and increased head impact magnitudes than did younger players, with every 1-year age increase associated with a 3.78 g and 602.81-rad/s2 increase in peak linear and rotational acceleration magnitude, respectively ( P≤ .005). Conclusion: Head IRs and magnitudes varied across seasons, thus highlighting multiple season and cohort data are valuable when providing estimates. Head IRs were relatively low across seasons, while linear and rotational acceleration magnitudes were relatively high.

scholarly journals Metatarsophalangeal Hyperextension Movement Pattern Related to Diabetic Forefoot Deformity

2016 ◽  
Vol 96 (8) ◽  
pp. 1143-1151 ◽  
Author(s):  
Victor A. Cheuy ◽  
Mary K. Hastings ◽  
Michael J. Mueller
Keyword(s):  
Diabetic Neuropathy ◽  
Plantar Flexion ◽  
Metatarsophalangeal Joint ◽  
Movement Pattern ◽  
Cross Sectional Study ◽  
Ankle Dorsiflexion ◽  
Cross Sectional ◽  
3 Dimensional ◽  
Foot Motion ◽  
Standing Up

Abstract Background Metatarsophalangeal joint (MTPJ) hyperextension deformity is common in people with diabetic neuropathy and a known risk factor for ulceration and amputation. An MTPJ hyperextension movement pattern may contribute to the development of this acquired deformity. Objective The purpose of this study was to determine, in people with diabetes mellitus and peripheral neuropathy (DM+PN), the ankle and MTPJ ranges of motion that characterize an MTPJ hyperextension movement pattern and its relationship to MTPJ deformity severity. It was hypothesized that severity of MTPJ deformity would be related to limitations in maximum ankle dorsiflexion and increased MTPJ extension during active ankle dorsiflexion movement tasks. Design A cross-sectional study design was used that included 34 people with DM+PN (mean age=59 years, SD=9). Methods Computed tomography and 3-dimensional motion capture analysis were used to measure resting MTPJ angle and intersegmental foot motion during the tasks of ankle dorsiflexion and plantar flexion with the knee extended and flexed to 90 degrees, walking, and sit-to/from-stand. Results The MTPJ extension movement pattern during all tasks was directly correlated with severity of MTPJ deformity: maximum ankle dorsiflexion with knee extended (r=.35; 95% confidence interval [CI]=.02, .62), with knee flexed (r=.35; 95% CI=0.01, 0.61), during the swing phase of gait (r=.47; 95% CI=0.16, 0.70), during standing up (r=.48; 95% CI=0.17, 0.71), and during sitting down (r=.38; 95% CI=0.05, 0.64). All correlations were statistically significant. Limitations This study was cross-sectional, and causal relationships cannot be made. Conclusions A hyperextension MTPJ movement pattern associated with limited ankle dorsiflexion has been characterized in people with diabetic neuropathy. Increased MTPJ extension during movement and functional tasks was correlated with severity of resting MTPJ alignment. Repetition of this movement pattern could be an important factor in the etiology of MTPJ deformity and future risk of ulceration.

scholarly journals The association of socio-demographic and environmental factors on childhood diarrhea in Cambodia

F1000Research ◽  
2020 ◽  
Vol 9 ◽  
pp. 303
Author(s):  
Vong Pisey ◽  
Pannee Banchonhattakit
Keyword(s):  
Maternal Age ◽  
Mixed Model ◽  
Linear Mixed Model ◽  
Secondary Data ◽  
Cross Sectional Study ◽  
Health Concern ◽  
Childhood Diarrhea ◽  
Public Health Concern ◽  
Cross Sectional ◽  
One Year

Background: Diarrhea is still the leading cause of childhood death worldwide, as well as a major cause for concern in developing countries. This study was conducted to investigate the factors related to childhood diarrhea in Cambodia. Methods: A cross-sectional study of the secondary data from the Cambodia Demographic and Health Survey 2014 was conducted using the combination of household data and children’s data. A generalized linear mixed model was used to analyze the determinant factors of childhood diarrhea. Results: The surveys included 2,828 children, aged 12 to 35 months. The prevalence of diarrhea in the last 2 weeks was 16.44% (95% CI: 14.72%-18.31%). Factors with statistically significant associations with childhood diarrhea in Cambodia were: maternal  unemployment, compared with being in employment (AOR = 1.43; 95% CI: 1.14-1.78); the child being male (AOR = 1.25; 95%CI: 1.02-1.53); the presence of unimproved toilet facilities (AOR = 1.17; 95%CI: 1.05-1.31) compared with improved toilet facilities; and unhygienic disposal of children’s stools (AOR = 1.32; 95%CI: 1.06-1.64) compared with hygienic disposal of children’s stools when controlling for other covariates. Both maternal age (one year older; AOR = 0.85; 95%CI: 0.78– 0.93) and child age (one month older; AOR = 0.86; 95%CI: 0.78-0.94) had significant negative associations with the occurrence of childhood diarrhea. Conclusion: Childhood diarrhea remains a public health concern in Cambodia. The probability of diarrhea occurring is shown to be increased by maternal unemployment, the sex of the child being male, lack of provision of improved toilet facilities, and the unhygienic disposal of children’s stools; whereas increasing maternal age and child’s age were associated with a reduced chance of diarrhea occurring. On the basis of these results, we recommend provision of programs focusing on reducing diarrhea through the construction of improved toilet facilities and the promotion of behavior to improve hygiene, specifically targeting younger mothers.

Wideband Absorbance in Young Infants (0–6 months): A Cross-Sectional Study

2014 ◽  
Vol 25 (05) ◽  
pp. 471-481 ◽  
Author(s):  
Sreedevi Aithal ◽  
Joseph Kei ◽  
Carlie Driscoll
Keyword(s):  
Mixed Model ◽  
Age Groups ◽  
Cross Sectional Study ◽  
Distortion Product Otoacoustic Emission ◽  
Sectional Study ◽  
Cross Sectional ◽  
Distortion Product ◽  
Young Infants ◽  
Developmental Effects ◽  
Data Points

Background: Wideband acoustic immittance (WAI) studies on infants have shown changes in WAI measures with age. These changes are attributed, at least in part, to developmental effects. However, developmental effects in young infants (0–6 mo) on WAI have not been systematically investigated. Purpose: The objective of this study was to compare wideband absorbance (WBA) in healthy neonates and infants aged 1, 2, 4, and 6 mo. Research Design: This was a prospective cross-sectional study. All participants were assessed by using 1-kHz tympanometry, distortion product otoacoustic emission (DPOAE) tests, and WBA tests. Study Sample: Participants included 35 newborns (35 ears), 16 infants aged 1 mo (29 ears), 16 infants aged 2 mo (29 ears), 15 infants aged 4 mo (28 ears), and 14 infants aged 6 mo (27 ears). For each participant, the ears that passed both high-frequency (1-kHz) tympanometry and DPOAE tests were included for analysis. Data Collection and Analysis: WBA was recorded at ambient pressure conditions, and the response consisted of 16 data points at 1/3-octave frequencies from 0.25 to 8 kHz. A mixed-model analysis of variance (ANOVA) was applied to the data in each age group to evaluate the effects of sex, ear, and frequency on WBA. WBA was compared between various age groups. In addition, a separate mixed-model ANOVA was applied to WBA data, and post hoc analyses with the Bonferroni correction were performed at each of the 16 data points at 1/3-octave frequencies across age groups to examine the effect of age on WBA. Results: For all age groups, WBA was highest between 1.5 and 5 kHz and lowest at frequencies of less than 1.5 kHz and greater than 5 kHz. A developmental trend was evident, with both the 0- and 6-mo-old infants being significantly different from other age groups at most frequencies. The WBA results exhibited a multipeaked pattern for infants aged 0 to 2 mo, whereas a single broad peaked pattern for 4- and 6-mo-old infants was observed. The difference in WBA between 0- and 6-mo-old infants was statistically significant across most frequencies. In contrast, the WBA results for 1- and 2-mo-old infants were comparable. There were no significant sex or ear effects on WBA for all age groups. Conclusions: Developmental effects of WBA were evident for infants during the first 6 mo of life. The WBA data can be used as a reference for detecting disorders in the sound-conductive pathways (outer and middle ear) in young infants. Further development of age-specific normative WBA data in young infants is warranted.

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