Standard Error Of Measurement Values Research Articles

Psychometric testing of the modified Care Dependency Scale for Rehabilitation

Objective: To determine the psychometric properties of the modified Care Dependency Scale for Rehabilitation. Design: All patients were assessed independently by a different set of two randomly selected nurses. Setting and subjects: A convenience sample consisting of 1197 patients and 42 nurses was recruited in an Austrian rehabilitation centre specialized on the treatment and care of neurological and orthopaedic patients. Measures: The Care Dependency Scale for Rehabilitation and the Barthel Index. Data analysis: To estimate aspects of reliability, Cronbach’s alpha, Cohen’s kappa, percentage agreement, intraclass correlation coefficient (ICC) and standard error of measurement (SEM) were calculated. To evaluate the construct validity, a factor analysis was conducted. Criterion-related validity was examined by comparing data of the modified Care Dependency Scale for Rehabilitation with the Barthel Index and Pearson calculation. Results: The calculation of Cronbach’s alpha yielded values of 0.97. Kappa values were between 0.89 and 0.96, values of percentage agreement between 96% and 99%, ICC values between 0.94 and 0.99, and SEM values between 0.08 and 0.17. Pearson (r) was 0.88. The factor analysis revealed a one-factor solution. Conclusion: The modified Care Dependency Scale for Rehabilitation shows a high internal consistency, as well as a high level of equivalence. Furthermore, criterion-related validity and construct validity have shown satisfying results.

Longitudinal validity and responsiveness of the Food Allergy Quality of Life Questionnaire – Parent Form in children 0–12 years following positive and negative food challenges

There are no published studies of longitudinal health-related quality of life (HRQL) assessments of food-allergic children using a disease-specific measure. This study assessed the longitudinal measurement properties of the Food Allergy Quality of Life Questionnaire - Parent Form (FAQLQ-PF) in a sample of children undergoing food challenge. Parents of children 0-12 years completed the FAQLQ-PF and the Food Allergy Independent Measure (FAIM) pre-challenge and at 2 and 6 months post food challenge. In order to evaluate longitudinal validity, differences between Group A (positive challenge) and Group B (negative challenge) were expected over time. We computed correlation coefficients between change scores in the FAQLQ-PF and change scores in the FAIM. To determine the minimally important difference (MID), we used distributional criterion and effect size approaches. A logistic regression model profiled those children falling below this point. Eighty-two children underwent a challenge (42 positive; 40 negative). Domains and total score improved significantly at pos-challenge time-points for both groups (all P<0.05). Sensitivity was demonstrated by significant differences between positive and negative groups at 6 months [F(2, 59)=6.221, P<0.003] and by differing improvement on relevant subscales (P<0.05). MID was 0.45 on a seven-point response scale. Poorer quality of life at baseline increased the odds by over 2.0 of no improvement in HRQL scores 6-month time-point. General maternal health (OR 1.252), number of foods avoided (OR 1.369) and children >9 years (OR 1.173) were also predictors. The model correctly identified 84% of cases below MID. The FAQLQ-PF is sensitive to change, and has excellent longitudinal reliability and validity in a food-allergic patient population. The standard error of measurement value of 0.5 points as a threshold for meaningful change in HRQL questionnaires was confirmed. The FAQLQ-PF may be used to identify problems in children, to assess the effectiveness of clinical trials or interventions, and to guide the development of regulatory policies.

Reproducibility of a measurement for latissimus dorsi muscle length

ABSTRACTLatissimus dorsi is a muscle theorized to undergo length changes due to shoulder region pathology or treatment such as stretching. A latissimus dorsi length measurement would be valuable to determine if length changes have occurred within an individual over time. With no such measurement known, we examined a proposed technique believed to isolate latissimus dorsi. The aim of this study was to determine how accurately a rater could reproduce this measurement in the same individual over a 6-week interval. Thirty subjects without shoulder symptoms were measured at 6-week intervals by either an experienced or novice clinician. A repeated-measures analysis of variance estimated the measurement error used for calculating intrarater correlation coefficients (ICC3,1). The standard error of measurement (SEM), confidence intervals (CI), and the smallest real difference (SRD) were also determined. The ICCs for all raters combined and for the separate groups indicated poor reliability. The SEM and SRD values were similar between groups, but they suggest poor measurement reproducibility in the same subject over a 6-week interval. This technique is not recommended for measuring latissimus dorsi length clinically to assess within-subject change over time.

A comparison of foot arch measurement reliability using both digital photography and calliper methods

BackgroundBoth calliper devices and digital photographic methods have been used to quantify foot arch height parameters. The purpose of this study was to compare the reliability of both a calliper device and digital photographic method in determining the arch height index (AHI).MethodsTwenty subjects underwent measurements of AHI on two separate days. On each day, AHI measurements during both sitting and standing were taken using the AHIMS and digital photographic methods by the same single tester. The intra-tester reliability of each measurement technique was assessed using intraclass correlation coefficients (ICC) and standard error of measurement (SEM). Additionally, the relationship between AHI measurements derived from the two different methods was assessed using a correlation analysis.ResultsThe reliability for both the AHIMS and digital photographic methods was excellent with ICC values exceeding 0.86 and SEM values of less than 0.009 for the AHI. Moreover, the reliability of both measurement techniques was equivalent. There was a strong positive correlation between the AHI values collected using both methods. AHI values calculated using the digital photographic method tended to be greater than those derived using the AHIMS.ConclusionDigital photographic methods offer equivalent intra-tester reliability to previously established calliper methods when assessing AHI. While AHI measurements calculated using both methods were highly related, the greater AHI values in the photographic method implied caution should be exercised when comparing absolute values between the two methods. Future studies are required to determine whether digital photographic methods can be developed with improved validity.

Between-day reliability of electromechanical delay of selected neck muscles during performance of maximal isometric efforts

BackgroundThe purpose of this study was to assess the between-day reliability of the electromechanical delay (EMD) of selected neck muscles during the performance of maximal isometric contractions in five different directions.MethodsTwenty-one physically active males participated in two testing sessions separated by seven to eight days. Using a custom-made fixed frame dynamometer, cervical force and surface electromyography (EMG) were recorded bilaterally from the splenius capitis, upper trapezius and sternocleidomastoid muscles during the performance of efforts in extension, flexion, left and right lateral bending, and protraction. The EMD was extracted using the Teager-Kaiser Energy Operator. Reliability indices calculated for each muscle in each testing direction were: the difference in scores between the two testing sessions and corresponding 95% confidence intervals, the standard error of measurement (SEM) and intra-class correlation coefficients (ICC).ResultsEMD values showed no evidence of systematic difference between the two testing sessions across all muscles and testing directions. The SEM for extension, flexion and lateral bending efforts ranged between 2.5 ms to 4.8 ms, indicating a good level of measurement precision. For protraction, SEM values were higher and considered to be imprecise for research and clinical purposes. ICC values for all muscles across all testing directions ranged from 0.23 to 0.79.ConclusionEMD of selected neck muscles can be measured with sufficient precision for the assessment of neck muscle function in an athletic population in the majority of directions tested.

Reliability of Passive Hip Extension Mechanical Parameters in Healthy Subjects

Objective: The objective was to estimate the reliability of three stiffness parameters (moment, angle and stiff- ness coefficient) of the hip extension movement, for three knee positions. Design: Twenty healthy subjects were assessed on two days separated by a one-week interval. A modified Biodex dyna- mometer was used to move the right lower limb passively in a side-lying position and to record the hip angle and moment during the movement. Three trials with the knee positioned at 0°, 45° and 90° of flexion were performed each day. Pas- sive stiffness was quantified by three parameters derived from the moment-angle curve of each subject. The generalizabil- ity theory was used to determine the reliability coefficients and standard errors of measurement (SEM) computed for a de- sign comprising five trials in one day. Results: Overall, the reliability coefficients were moderate to good with values ranging from 0.58 to 0.83 at the three knee positions. The highest SEM values were 4.15 Nm, 8.4° and 0.15 Nm/° for the moment, angle and stiffness coefficient pa- rameters, respectively. The main source of error variance was related to the subject-day interaction factor and a systematic day effect was also noted. Conclusions: This study constitutes a first step towards objective evaluation of hip extension joint stiffness. Future studies will be needed to better control the alignment of the hip to reduce the systematic day error on the stiffness parameters.

Reliability of absolute versus log-transformed regression models for examining the torque-related patterns of response for mechanomyographic amplitude

This study examined the test-retest reliability of the slopes (b) and y-intercepts (a) of the absolute and log-transformed regression models applied to the mechanomyographic amplitude (MMG(RMS)) versus torque (TQ) relationship. Fifteen participants (mean+/-SD age=23+/-4 yrs) performed two isometric maximal voluntary contractions (MVCs) and ten randomly ordered isometric leg extensions from 5% to 95% of their MVC during three separate trials. MMG(RMS) was recorded from the vastus lateralis during each MVC. Intraclass correlation coefficients (ICCs) and standard errors of measurement (SEMs) were calculated for test-retest reliability. ICCs for the b and a terms were 0.89 and 0.90 for the log-transformed and 0.85 and 0.76 for the absolute relationships, respectively. The SEM values (expressed as a percentage of the mean) for the b and a terms were 9.7% and 16.4% for the log-transformed and 18.9% and 57.1% for the absolute relationships, respectively. These results indicated that the b and a terms from both the absolute linear and log-transformed MMG(RMS) versus TQ relationships were relatively reliable (ICCs), however, the SEMs for the log-transformed relationships were lower than the absolute linear models. Furthermore, the b term from the log-transformed relationships may provide unique information regarding the nonlinear characteristics (plateau points) of the MMG(RMS) versus TQ relationship, whereas the a term may indicate upward or downward shifts in MMG(RMS) across the TQ spectrum. Thus, the log-transformed MMG(RMS) versus TQ relationships may offer an attractive alternative method for reliably quantifying and tracking changes in the TQ-related patterns of response for MMG(RMS) on a subject-by-subject basis.

Reliability of transcranial magnetic stimulation-related measurements of tibialis anterior muscle in healthy subjects

The main purpose of this study was to determine the reliability of transcranial magnetic stimulation (TMS)-related measurements linked to the corticospinal control of the tibialis anterior (TA) muscle in healthy subjects. Inter-investigator and intra-investigator (within-session with a 1.5-h interval; between-session with a 4-week interval) reliability of the motor threshold, recruitment curve with its slope and MEP area at the plateau, MEP latency, maximum MEP (MEPmax) area, and duration of the maximum and minimum silent period (SPmax and SPmin) were assessed in 50 (29 men and 21 women) healthy subjects (mean age 44.8 years, range 22-74 years) using intraclass correlation coefficients (ICC), standard error of measurement (SEM) and smallest real difference (SRD). The high ICC values and lower SEM and SRD values indicate a good intra- and inter-investigator reliability for motor threshold (ICC range 0.94-0.98), MEP latency (ICC range 0.79-0.93), SPmax (ICC range 0.89-0.95) and SPmin (ICC range 0.79-0.81) in healthy subjects. These results suggest that the TMS-related measurements investigated are reliable in healthy subjects. These data could be useful in further studies on cortical excitability changes, such as those induced by therapeutic interventions (e.g. rehabilitative treatment).

Reproducibility and validity of heart rate variability and respiration rate measurements in participants with prolonged fatigue complaints

(1) To evaluate reproducibility of heart rate variability (HRV) and respiration rate (RR) measurements during reclining and cycling in participants with prolonged fatigue and (2) to assess concurrent validity between HRV and RR measurements and fatigue. Twenty-seven subjects reporting prolonged fatigue complaints resulting in functional impairments participated in the study. Fatigue complaints and functional impairments were assessed. Two to 4 days later, they underwent two repeated measurements of time-domain HRV (SDNN and RMSSD) and RR with 3-4 days between. Intra-class correlation coefficients (ICCs) and standard error of measurement (SEM) were calculated to define reproducibility and Pearson correlations were calculated to define concurrent validity. ICC means for SDNN and RMSSD during reclining and cycling ranged from 0.86 to 0.93. For RR the ICC means were 0.65 and 0.85 for reclining and cycling, respectively. The SEM values (ms) for SDNN and RMSSD ranged from 1.08 to 7.71 while the SEM values for RR were 1.82 and 1.99 for reclining and cycling, respectively. The Pearson correlations were non-significant and ranged from -0.05 to 0.15. There was good reproducibility of HRV and RR in participants with prolonged fatigue complaints. Concurrent validity between HRV and RR measurements and fatigue was low.

The Stroke Impact Scale 3.0

We sought to assess the psychometric attributes of the Brazilian version of the Stroke Impact Scale (SIS) 3.0 in stroke survivors. Patients were evaluated by the National Institutes of Health Stroke Scale, Mini-Mental State Examination, Barthel Index, Lawton Instrumental Activities of Daily Living Scale, modified Rankin Scale, Geriatric Depression Scale, and Hospital Anxiety and Depression Scale. Health-related quality of life was evaluated with the MOS-Short Form 36 and SIS 3.0. One hundred seventy-four stroke survivors were assessed (mean age, 56.9 years; 55.2% male). Hand function had a prominent floor effect (45.9%), whereas a ceiling effect was observed in the communication domain (17.3%). The internal consistency of SIS (Cronbach's alpha=0.94) and SIS domains (item-dimension correlation, 0.17 to 0.89) were satisfactory; only the emotion domain had poor internal consistency (Cronbach's alpha=0.49). Test-retest reliability was evaluated in 50 consecutive patients. Concerning the stability of the SIS, the weighted kappa values ranged from 0.33 (item 3a) to 0.94 (item 7e). Intraclass correlation coefficient values for the SIS domains ranged from 0.48 (emotion) to 0.94 (hand function). Standard error of measurement values for SIS domains ranged from 6.85 (mobility) to 9.63 (social participation). Regarding convergent validity, a significant correlation (Spearman's correlation coefficient, P<0.0001) was found between the SIS composite physical domain and the National Institutes of Health Stroke Scale (-0.69), modified Rankin Scale (-0.81), Barthel Index (0.87), Lawton Scale (0.76), and MOS-Short Form 36 physical component summary (0.61). SIS domain scores significantly decreased as modified Rankin Scale scores increased (discriminative validity; ANOVA, P<0.0001). The Brazilian version of SIS 3.0 has satisfactory psychometric properties and can be used in stroke survivors to assess health-related quality of life.

Reliability of Mechanomyographic Amplitude Recorded during Isometric Step Versus Ramp Muscle Actions

PURPOSE: To examine the test-retest reliability of mechanomyographic (MMG) amplitude of the vastus lateralis muscle during isometric step versus ramp muscle actions. METHODS: Nineteen subjects (mean ± SD age = 24 ± 4 yrs) completed familiarization trial and 3 experimental trials. Each trial was separated by 3-5 days and occurred at the same time of day. The 3 experimental trials were used to calculate intraclass correlation coefficients (ICC) and standard errors of measurement (SEM) for test-retest reliability. Repeated measures ANOVAs were used to quantify systematic variability. During each trial, subjects performed two isometric maximal voluntary contractions (MVC) prior to 10 randomly-ordered isometric step muscle actions at 5, 15, 25, 35, 45, 55, 65, 75, 85, and 95% MVC and two 6-s isometric ramp muscle actions with linear increases in torque from 5% to 100% MVC. MMG amplitude (rms) was calculated for each %MVC during the step and ramp muscle actions. RESULTS: Systematic variability was only present at 5% MVC (p=0.012) during the ramp muscle actions. The means for all other %MVCs during the ramp and all step muscle actions did not vary across trials p=0.300-0.996). The figure displays the ICCs and SEM values (expressed as a decimal percentage of the mean). FU1 CONCLUSIONS: The magnitudes of the ICCs were moderate to high and were generally strongest (>0.70) from 35% to 100% MVC. The SEMs were stable and ranged from 15-29% and 20-34% of the mean values for the step and ramp muscle actions, respectively. ICCs were slightly lower, while SEMs were consistently higher for the ramp than the step muscle actions. This may have reflected the shorter signal epochs and general nonstationarity of the ramp compared to the step muscle actions.

Validity of a Repeated-Sprint Test for Football

Three studies involving 108 football players were conducted to examine the reliability of a repeated-shuttle-sprint ability (RSSA) test and its ability to differentiate between players of various competitive levels and playing positions. Study 1: Short-term reliability was determined in 22 professional players completing the RSSA test (6 x 40-m sprints with 20 s of recovery between sprints) on two separate occasions. Study 2: Long-term reliability (seasonal changes) was examined in 31 professional players completing the RSSA test four times (during the preseason period, at the start, middle and end of the competitive season). Study 3: 108 players were divided and compared according to competitive level or playing position. Standard error of measurement values expressed as coefficient of variation for RSSA mean time and best time were 0.8 and 1.3 % (short-term reliability) and 0.9 and 1.2 % (long-term reliability), respectively. The smallest worthwhile changes were 0.5 % for both mean and best time. Professional players showed better RSSA performance than amateur players, and defenders displayed the lowest RSSA performance. In conclusion, the RSSA test showed adequate construct validity but only RSSA mean time showed sufficient reliability to detect large training-induced changes but not small important differences.

Psychometric attributes of the SCOPA‐COG Brazilian version

Cross-cultural adaptation and independent psychometric assessment of the Scales for Outcomes in Parkinson's disease-Cognition (SCOPA-COG), Brazilian version was performed. Parkinson's disease (PD) patients were evaluated by means of the SCOPA-Motor scale, Hoehn and Yahr staging (HY), Clinical Impression of Severity Index-PD (CISI-PD), Parkinson Psychosis Rating Scale, and Hospital Anxiety and Depression Scale. Cognition was evaluated using the Mini-Mental State Examination (MMSE), Short Portable Mental Status Questionnaire (SPMSQ), and SCOPA-COG. The following attributes were explored: acceptability, scaling assumptions, reliability, precision, and construct validity. One hundred fifty-two patients were assessed (mean age, 63.2 years; disease duration, 7.8 years; median HY stage, 3). Mean SCOPA-COG and MMSE were 18.2 and 25.7, respectively. The internal consistency of the SCOPA-COG (Cronbach's alpha = 0.81; item-total correlation, 0.38-0.62) was satisfactory. While the intraclass correlation coefficient value was 0.80, weighted kappa ranged from 0.30 (dice task) to 0.72 (animal fluency task). The standard error of measurement value for the SCOPA-COG was 3.2, whereas the smallest real difference was 8.9. SCOPA-COG total scores significantly decreased as the HY stage increased (Kruskal-Wallis, P < 0.0001). Age, years of education, and PD duration (all, P < 0.001) were observed to have an independent, significant effect on the SCOPA-COG. The SCOPA-COG is a short, reliable, valid instrument that is sensitive to cognitive deficits specific to PD.

Reliability of hand-held dynamometry and functional strength tests for the lower extremity in children with Cerebral Palsy

Purpose. To evaluate the intertester reliability of two methods for measuring lower-limb strength in children with cerebral palsy (CP).Method. Twenty-five subjects with CP (7 – 17 years of age) participated in this study. Lower-limb muscle strength was measured on 2 occasions using a Hand-held Dynamometer (HHD; break-method and make-method) and a 30-sec Repetition Maximum (RM) during three functional strength tests for the lower extremities. Reliability was measured using the intraclass correlation coefficients (ICCs), the standard error of measurement (SEM) and the coefficient of variation (CV).Results. The intertester reliability of strength measurement using a HHD was questionable with ICC values ranging from 0.42 – 0.73 for the break-method, and from 0.49 – 0.82 for the make-method. The SEM and CV (%) values ranged from 27.9 – 58.9 and 22.2 – 35.3% for the break-method, and from 30.6 – 52.7 and 16.2 – 56.2% for make-method. The intertester reliability of strength measurement using the 30-sec RM was acceptable with ICC values ranging from 0.91 – 0.96, and SEM and CV (%) values ranging from 1.1 – 2.6 and 10.9 – 39.9% for the functional exercises.Conclusion. The intertester reliability of measuring muscle strength of the lower extremities using a hand-held dynamometer is questionable. The intertester reliability of the 30-sec RM for the lower extremity is acceptable.

Auditory steady-state responses in normal hearing adults: A test-retest reliability study

The test-retest reliability of the auditory steady-state response (ASSR) has received limited attention. Therefore, the aim was to assess the test-retest reliability of an 80-Hz multiple-ASSR system in normal-hearing subjects by a comprehensive set of statistical methods. Twenty-nine participants (15 females) aged between 18 and 30 years contributed to two sessions (test-retest), and the ASSR thresholds were determined with a descending search protocol using a 10-dB precision. The test-retest reliability was assessed by a three-layered approach which consisted of Pearson product-moment correlation, analysis of variance (ANOVA), and standard error of measurement (SEM). The correlations for ASSR thresholds ranged from poor (0.34) for 500 Hz CF to moderate (0.55) for 1000, 2000, and 4000 Hz CF. A two-way ANOVA of the difference scores (ASSR threshold minus behavioral threshold) demonstrated no significant difference between test and retest. The SEM determined the normal tolerance for clinical error of repeated thresholds and the ASSR SEM values fell well within ±10 dB HL. This investigation shows that the multiple ASSR-technique produces a clinically acceptable test-retest reliability for normal-hearing adults.

Interrater Reliability of Algometry in Measuring Pressure Pain Thresholds in Healthy Humans, Using Multiple Raters

To evaluate interrater reliability using 5 newly trained observers in the assessment of pressure pain threshold (PPT) using a fixed-angle algometer. The study design comprised 2 phases. Phase 1: 5 undergraduate physical therapists were trained in algometry at a predefined angle, at a rate of 5 Newtons (N)/s, to the first dorsal interosseous muscle. Each observer then underwent a competency test of the application speed. The aim was to achieve repeated applications at 5 N/s without visual feedback from the algometer. Phase 2: the 5 observers measured PPT of 13 healthy volunteers, at the first dorsal interosseous muscle. The sequence of observer measurements for each participant was randomized. Mean PPT values for each observer were analyzed using repeated measures analysis of variance, intraclass correlation coefficient (ICC2,1), and standard error of measurement, with 95% confidence intervals (CIs). No significant differences between observers' mean values were found (P=0.094), suggesting no bias. The ICC was 0.91 (95% CI 0.82, 0.97). The standard error of measurement value was 6.27 N/cm (95% CI 5.35, 7.59). Differences in PPT measurements of more than 17.39 N/cm (1.77 kg/cm) are likely to exceed the magnitude of measurement error, and could be used to indicate true change. This margin of error is, however, somewhat larger than a previously proposed minimum clinically important difference in PPT of 14.71 N/cm (1.5 kg/cm). This study provides new evidence that trained observers can apply an algometer at a consistent rate and provide highly reliable measures of PPT in healthy humans, when PPT is calculated as the mean of 3 trials.

Standard error of measurement as a valid alternative to minimally important difference for evaluating the magnitude of changes in patient-reported outcomes measures

To assess the degree of agreement between standard error of measurement (SEM) and minimally important difference (MID) criteria to evaluate the magnitude of the change caused by a medical intervention. Data were obtained from a cohort of 603 patients with neuropathic pain undergoing analgesic treatment with gabapentin who completed four health scales: Medical Outcomes Study Sleep Scale, Sheehan Disability Scale, Covi Anxiety Scale, and Raskin Depression scale. After calculating MID and SEM values for all scales, patients were classified into three categories: improvement, no change, and worsening. Agreement between the two criteria was assessed using Cohen's kappa index of agreement and Kendall's tau-b linear correlation coefficient. The 1 SEM criterion showed the highest agreement (kappa=0.68-1.00) and correlation (tau-b=0.75-1.00) with the MID criterion. Sensitivity analysis performed in gabapentin responders and nonresponders confirmed the results of the main analysis. The 1 SEM criterion is a valid alternative to the MID criterion to evaluate the magnitude of the change produced in patient-reported health outcomes measures.

Ovarian Volume Measurements in Mice With High-Resolution Ultrasonography

The aim of our study was to evaluate the intraobserver and interobserver variability of ovarian volume measurements in mice with high-resolution 2-dimensional ultrasonography (2DUS) and 3-dimensional ultrasonography (3DUS). Ovaries of 10 nude mice were visualized with a small-animal ultrasound scanner and a 40-MHz probe. For each ovary, volume was measured 3 times by 2 independent readers using both 2DUS and 3DUS methods. The 2DUS method used a biplane ellipsoid model. The 3DUS method estimated the volume by integrating 10 to 12 parallel image planes of the ovary after semiautomated outlining of the boundaries. For each type of measurement, intraobserver and interobserver standard error of measurement (SEM) values and minimal detectable volume changes were calculated by analysis of variance. Two-dimensional ultrasonography showed much poorer reproducibility, with higher absolute intraobserver and interobserver SEM values (0.50 and 0.61 mm3, respectively) than 3DUS (0.20 and 0.35 mm3; P < .01). Relative intraobserver and interobserver SEM values were also much higher for 2DUS (12.20% and 14.88%) than for 3DUS (5.12% and 8.97%; P < .01). The minimal volume changes that could be detected with a 95% confidence level in successive measurements by the same (or different) observers were 33.90% (41.22%) for 2DUS and 14.10% (24.87%) for 3DUS. High-resolution 3DUS can provide a reliable tool for noninvasive, longitudinal ovarian volume measurements in mice.

Intrarater and Interrater Reliability of Assessment of Lumbar Multifidus Muscle Thickness Using Rehabilitative Ultrasound Imaging

Within-session intrarater and interrater reliability study. To establish the intrarater and interrater reliability of thickness measurements of the multifidus muscle in a parasagittal plane, conducted by an experienced ultrasound operator and a novice assessor. There is considerable evidence for the important role of the multifidus muscle in segmental stabilization of the lumbar spine. The cross-sectional area of the multifidus muscle has been assessed in healthy subjects and patients with low back pain using real-time ultrasound imaging. However, few studies have measured the thickness of the multifidus muscle using a parasagittal view. The thickness of the multifidus muscle was measured at rest, using real-time ultrasound imaging, in 10 subjects without a history of low back pain, at the levels of the L2-3 and L4-5 zygapophyseal joints. The measure was carried out 3 times at each level by 2 assessors (1 experienced, 1 novice). Intrarater (model 3) and interrater (model 2) reliability was assessed by calculation of an F statistic (analysis of variance), the intraclass correlation coefficient (ICC), and the standard error of measurement (SEM). On the basis of an average of 3 trials, the 2 operators showed very high interrater agreement on the measurement of thicknesses at the L2-3 level (ICC2,3 = 0.96; 95% CI: 0.84 to 0.99) and the L4-5 vertebral level (ICC2,3 = 0.97; 95% CI: 0.87 to 0.99), with no systematic differences in muscle size across operators (P > .05). Interrater reliability was relatively lower for the L2-3 level (ICC2,1 = 0.85; 95% CI: 0.51 to 0.96) than the L4-5 level (ICC2,1 = 0.87; 95% CI: 0.52 to 0.97) when a single trial per rater was used, but these values still indicated a high level of agreement. In addition, the novice and experienced operator produced reliable intrarater measurements at L2-3 (ICC3,1 = 0.89; 95% CI: 0.72 to 0.97 and 0.94; 95% CI: 0.86 to 0.99) and at L4-5 (ICC3,1 = 0.88; 95% CI: 0.68 to 0.97 and 0.95; 95% CI: 0.86 to 0.99), with no systematic differences in muscle size across trials (P > .05). The consistently low SEM values also indicate low measurement error. A novice and an experienced assessor were both able to reliably perform this measure at rest for 2 vertebral levels using real-time ultrasound imaging. An average of 3 trials produced higher interrater reliability scores, though using a single trial per rater was also reliable.

Reliability Of Accelerometry-based Activity Monitor Output During Treadmill Walking

While reliability is a necessary prerequisite to measurement validity, reliability is rarely assessed for accelerometry-based activity monitors (AC) prior to use by researchers. PURPOSE: The study evaluated the test-retest reliability of an AC worn at different positions on the body during controlled walking trials on a treadmill. METHODS: Twenty subjects (10 men, Mean±SD: 23±3 yrs, 181.7±8.4 cm, 77.8±14.0 kg, 23.5±3.9 kg/m2; 10 women: 22±3 yrs, 167.2±5.7 cm, 64.6±13.8 kg, 23.0±4.2 kg/m2) walked at six speeds (40.2, 53.6, 67.0, 80.4, 93.8, 107.2 m/min) on a treadmill. The AC was worn on the left and right hip just anterior to the iliac crest and in line with the mid-axillary line of the thigh. AC monitors were also worn on the lateral aspect of the left and right ankles just proximal to the medial malleolus. Subjects walked three trials of 1 min at each treadmill speed while the order of speeds tested was counterbalanced across subjects. Using the raw AC output (counts/min) for each of the three trials and four wearing locations, reliability measures included the standard error of measurement (SEM), the coefficient of variation (CV, %), and the intraclass correlation (ICC). Standard formulae were used to compute the SEM and CV, while the ICC for AC output at each walking speed and wearing location were determined using a 2-factor RMANOVA. RESULTS: ICC values across all treadmill speeds and AC monitor locations were high when evaluated across three trials (0.97-0.99) and remained high when extrapolated to a single trial (0.91-0.99). Both SEM (0.9-2.3 counts/min) and CV (1.7-6.3%) values were consistently low for the ankle monitors across all walking speeds, though CV values tended to be highest (4.7-6.3%) at the slowest speed. SEM values were similarly low (1.0-2.7 counts/min) for the hip monitors, but CV values ranged from 1.8% to 14.0% with the highest values observed at the two lowest speeds. CONCLUSIONS: Reliability was acceptable for output from both the ankle and hip worn AC monitors during the five fastest walking trials. Indicators of low reliability (high CV) were present for the slowest walking trial, especially for the monitors worn on the hip. These results indicate that the AC monitor can be considered a reliable tool for assessing physical activity.