Reliability Of Repeated Measurements Research Articles

The retest reliability of the six‐minute walk test in patients referred to a cardiac rehabilitation programme

The purpose of this paper was to determine if the Six-minute Walk Test (6MWT) was a reliable exercise test for patients referred to cardiac rehabilitation when up to three tests were performed and to determine if test scores differed according to between-test time interval. Thirty adults aged 63 ± 7.9 years referred to cardiac rehabilitation participated in a repeated measures reliability trial. Participants completed three 6MWTs within a one-week period. Participants were randomly allocated to one of three groups: on the first day, Group A completed three walks, Group B completed two walks and Group C completed one walk. Relative reliability was expressed in a ratio (ICC(2,1) ), and absolute reliability was expressed in metres (95% confidence intervals) for group and individuals. The 6MWT demonstrated a high level of relative reliability (intraclass correlation coefficients [ICC] = 0.94) across the three walks. There was no statistically significant difference between the test scores of the three groups. However, there was an increase in distance walked from the first to the second to the third 6MWT. Absolute reliability indicated that a change of at least 44 m would be required to be interpreted as true change in a group, and at least 95 m to be interpreted as true change in an individual with 95% confidence. Three 6MWTs completed in relatively short timeframes were not sufficient for reliable results as there was an increase in the distance walked, and relatively large increases in distances would be required to be interpreted as change. It did not make any difference whether the tests were all completed on one day or over one week. This study highlighted problems that may arise when relying on reliability coefficients alone to interpret reliability. These results suggest that the 6MWT may not have sufficient reliability to be a suitable test to evaluate exercise tolerance in patients referred to cardiac rehabilitation.

Inter‐Rater Reliability of Ultrasound Imaging of the Trunk Musculature Among Novice Raters

The purpose of this study was to determine the inter-rater reliability of ultrasound imaging for assessing trunk muscle morphologic characteristics at rest and while contracted among different pairs of novice raters. The secondary purpose was to compare 3 different measurement techniques for assessing lateral abdominal muscle thickness. A single-group repeated measures reliability study was conducted on 21 healthy participants (mean ± SD, 21.5 ± 4.4 years; 5 female and 16 male) without low back pain. Ultrasound images of the transversus abdominis, internal oblique, rectus abdominis, and lumbar multifidus muscles were obtained by different pairs of novice raters in a counterbalanced order. All raters received a standardized training program before obtaining measurements. The intraclass correlation coefficient (1, 3) point estimates ranged from 0.86 to 0.94; the standard error of the measurement ranged from 0.04 to 0.16 cm for the thickness values and 0.67 cm(2) for the cross-sectional area of the rectus abdominis muscle. There was no meaningful difference between the different measurement techniques used to analyze the lateral abdominal muscles. Good to excellent reliability was obtained for all measures by novice raters. Minimal differences in reliability were noted between the different measurement techniques to assess lateral abdominal muscle thickness.

The Effect of Mood on Post-Operative Pain and the Reliability and Validity of the Wisconsin Brief Pain Questionnaire Adapted on Black South Africans

Pain is a multidimensional phenomenon and the primary objective of all assessment tools is to gather accurate, subjective and objective information relevant to the pain that the patient is experiencing. This information plays a vital role in the diagnostic process and the treatment given to the patient. Thus it is of paramount importance that these pain measures are valid and reliable. Measures of pain are predominately developed in Western countries. This study investigated pre-surgical moods and their effect on acute pain following surgery including the reliability and validity of the Profile of Mood State (POMS), Visual Analogue Scale (VAS) and Wisconsin Brief Pain Questionnaire (WBPQ). These measures in particular have been developed in the United States of America and had to be adapted to the South African context using Setswana-speaking participants at George Mukhari Hospital formerly known as Ga-Rankuwa Hospital in South Africa. A biographical questionnaire was developed by the researcher for gathering background information of the participants. The POMS and the WBPQ were translated from English to Setswana using back-translation and were administered to a sample of 58 patients pre-operatively. VAS and WBPQ were administered post-operatively. The POMS was administered to determine the relationship of mood states to postoperative pain. Correlations were calculated between the six mood states scales that showed acceptable reliability but divergent validity was not confirmed. Concurrent and predictive validity between VAS and WBPQ was high and both measures have reasonable repeated-measures reliability.

A method for reliability analysis of speed-related repeated measures gait data

Reliability should be addressed for measures used in gait studies. Many protocols designed for experimental or clinical research request subjects to walk repeatedly at different steady-state walking speeds. Such data lend themselves to reliability analysis, rendering a separate reliability test session superfluous. Thus human and time resources are saved, and the reported reliability relates directly to the study population and occasion at hand. In this report a procedure is introduced where residuals from individual speed related curve estimates are regarded as measurement error. If there is no speed related trend in data, the procedure will yield identical results to a usual repeated measures reliability analysis where all within-subject variability is regarded as measurement error.

Reliability of Rehabilitative Ultrasound Imaging of the Transversus Abdominis and Lumbar Multifidus Muscles

Koppenhaver SL, Hebert JJ, Fritz JM, Parent EC, Teyhen DS, Magel JS. Reliability of rehabilitative ultrasound imaging of the transversus abdominis and lumbar multifidus muscles. Objectives To evaluate the intraexaminer and interexaminer reliability of rehabilitative ultrasound imaging (RUSI) in obtaining thickness measurements of the transversus abdominis (TrA) and lumbar multifidus muscles at rest and during contractions. Design Single-group repeated-measures reliability study. Setting University and orthopedic physical therapy clinic. Participants A volunteer sample of adults (N=30) with current nonspecific low back pain (LBP) was examined by 2 clinicians with minimal RUSI experience. Interventions Not applicable. Main Outcome Measures Thickness measurements of the TrA and lumbar multifidus muscles at rest and during contractions were obtained by using RUSI during 2 sessions 1 to 3 days apart. Percent thickness change was calculated as thickness contracted–thickness rest/thickness rest. Intraclass correlation coefficients (ICC) were used to estimate reliability. Results By using the mean of 2 measures, intraexaminer reliability point estimates (ICC 3,2) ranged from 0.96 to 0.99 for same-day comparisons and from 0.87 to 0.98 for between-day comparisons. Interexaminer reliability estimates (ICC 2,2) ranged from 0.88 to 0.94 for within-day comparisons and from 0.80 to 0.92 for between-day comparisons. Reliability estimates comparing measurements by the 2 examiners of the same image (ICC 2,2) ranged from 0.96 to 0.98. Reliability estimates were lower for percent thickness change measures than the corresponding single thickness measures for all conditions. Conclusions RUSI thickness measurements of the TrA and lumbar multifidus muscles in patients with LBP, when based on the mean of 2 measures, are highly reliable when taken by a single examiner and adequately reliable when taken by different examiners.

Reliability of a Measurement of Neck Flexor Muscle Endurance

Neck flexor muscle endurance has been negatively correlated with cervical pain and dysfunction. The purposes of this study were to determine rater reliability in subjects both with and without neck pain and to determine whether there was a difference in neck flexor muscle endurance between the 2 groups. Forty-one subjects with and without neck pain were enrolled in this repeated-measures reliability study. Two raters used an isometric neck retraction test to assess neck flexor muscle endurance for all subjects during an initial session, and subjects without neck pain returned for testing 1 week later. For the group without neck pain, intrarater reliability was good to excellent (intraclass correlation coefficient [ICC(3,1)]=.82-.91), and interrater reliability was moderate to good (ICC[2,1]=.67-.78). The associated standard error of measurement (SEM) ranged from 8.0 to 11.0 seconds and from 12.6 to 15.3 seconds, respectively. For the group with neck pain, interrater reliability was moderate (ICC[2,1]=.67, SEM=11.5). Neck flexor muscle endurance test results for the group without neck pain (mean=38.95 seconds, SD=26.4) and the group with neck pain (mean=24.1 seconds, SD=12.8) were significantly different. Reliability coefficients differed between the 2 groups and ranged from moderate to excellent and improved after the first test session. The interrater reliability of data obtained with the neck flexor muscle endurance test in people with neck pain must be improved in order for clinicians to distinguish a clinically meaningful change from measurement error. Neck flexor muscle endurance was both statistically and clinically greater for subjects without neck pain than for those with neck pain.

How well does the Canadian haemophilia Outcomes‐Kids' Life Assessment Tool (CHO‐KLAT) measure the quality of life of boys with haemophilia?

It is important to measure the quality of life (QoL) of boys with haemophilia, because the diagnosis has a significant impact on their lives and this impact fluctuates over time. A disease-specific measure of QoL is required because the aspects of life that are affected by haemophilia may differ from those assessed by generic QoL measures. This paper describes the final phase of development of a disease-specific measure of QoL for boys with haemophilia: the Canadian Haemophilia Outcomes-Kids Life Assessment Tool (CHO-KLAT). A 79-item version of the CHO-KLAT was administered to 52 children. A detailed item analysis was conducted to shorten the CHO-KLAT. The reliability of the revised version was assessed using intraclass correlation coefficients. Validity was assessed by comparing it to the PedsQL and the HaemoQoL. The item analysis resulted in the retention of 35 strongly performing items (CHO-KLAT(35)). These items were aggregated into the CHO-KLAT(35) summary score. Repeated measures reliability of the CHO-KLAT(35) was 0.74 for children and 0.83 for parents, and the child-parent concordance was 0.75. The validity of the CHO-KLAT(35) was confirmed by a correlation of 0.78 with the Haemo-QoL and of 0.59 with the PedsQL. The CHO-KLAT(35) is a reliable and valid measure of QoL for boys with haemophilia.

Establishing the reliability of mobility milestones as an outcome measure for stroke

Baer GD, Smith MT, Rowe PJ, Masterton L. Establishing the reliability of mobility milestones as an outcome measure for stroke. Arch Phys Med Rehabil 2003;84:977–81. Objective:To establish intrarater, interrater, and test-retest reliability of a standardized measure of mobility, “mobility milestones,” incorporating sitting balance, standing balance, and walking ability. Design:Repeated-measures reliability study by using video data of patients with stroke. Setting:Physiotherapy and rehabilitation departments in Scotland. Participants:Forty physiotherapists recruited from within the Lothian region: 20 senior physiotherapists with at least 3 years of experience working with neurologic patients and 20 staff grade physiotherapists with less than 12 months of experience working with neurologic patients. Intervention:Videotape comprising 40 clips (36 original clips, 4 repeated clips) of stroke patients of differing levels of ability attempting the mobility milestones was produced. After a short training session in the interpretation and application of the mobility milestones, each physiotherapist viewed the tape separately and scored whether the milestone had been achieved or not. This was repeated at a separate test session 2 weeks later. Main Outcome Measure:Score for each mobility milestone. Results:Kappa statistics were used to determine interrater reliability and showed good (.61–.80) to very good (.81–1.0) reliability for 3 of 4 milestones. Intraclass correlation coefficients (ICCs) were used to determine intrarater reliability of the 4 repeated clips and showed 75% of all subjects had high (ICC2,1=.91–1.0) reliability. The ICC2,1 for test-retest reliability showed a similar pattern, with 70% of subjects showing good (.81–.90) or high (.91–1.0) reliability. Conclusions:The mobility milestones showed favorable levels of reliability when used by experienced or novice physiotherapists. The milestones can be adopted as a simple clinical outcome measure for use with stroke. Further research is required to establish reliability levels when the measure is used by different rehabilitation professionals.

Reliability of chiropractic methods commonly used to detect manipulable lesions in patients with chronic low-back pain

Objective: To assess the intraexaminer and interexaminer reliability of a multidimensional spinal diagnostic method commonly used by chiropractors.Design: An intraexaminer and interexaminer Latin square, repeated measures reliability study. The techniques of diagnosis under investigation included visual postural analysis, pain description by the patient, plain static erect x-ray film of the lumbar spine, leg length discrepancy, neurologic tests, motion palpation, static palpation, and orthopedic tests.Participants: Three experienced chiropractors examined 19 patients, and 2 experienced chiropractors examined 10 and 9 patients, respectively, who were suffering from chronic mechanical low-back pain.Results: Intraexaminer reliability of the decision to manipulate a certain spinal segmental level was moderate (κ = 0.47). The interexaminer agreement pooled across all spinal joints indicated fair agreement (κ = 0.27). Interexaminer reliability for individual examiner pairs for the L4/L5 segmental level was slight (κ = 0.09). At the L5/S1 level, the interexaminer reliability was fair (κ = 0.25). For the sacroiliac joints, interexaminer reliability was slight (κ = 0.04 and 0.14).Conclusion: This study of commonly used chiropractic diagnostic methods in patients with chronic mechanical low-back pain to detect manipulable lesions in the lower thoracic spine, lumbar spine, and the sacroiliac joints has revealed that the measures are not reproducible. The implementation of these examination techniques alone should not be seen by practitioners to provide reliable information concerning where to direct a manipulative procedure in patients with chronic mechanical low-back pain.

Reliability of physical performance tests in four different randomized clinical trials

Objectives: (1) To assess the test-retest reliability of physical performance tests in subject groups with different levels of impairment and disability, and (2) to assess the stability of these tests over different time intervals. Design: Test-retest, repeated measures reliability design. Setting: (1) A university's center for aging and research center, (2) a continuing care retirement community, and (3) an extended care and rehabilitation center at a Veterans Affairs medical center. Subjects: Twenty-four community-dwelling elders, 15 community-dwelling elders with Parkinson disease, 12 older women with vertebral osteoporosis and compression fractures, and 14 elderly nursing home residents. Measures: Lower extremity isometric strength (ankle dorsiflexion, hip abduction), spinal configuration (thoracic kyphosis, lumbar lordosis), lumbosacral motion (flexion, extension), and timed measures of the ability to get in and to get out of bed at a usual pace. Results: Most of the within-group intraclass correlation coefficients (ICCs) were good to excellent (.70 to .97). Overall, ICCs for all groups combined were between .70 and .96, and no decrement in reliability was noted after controlling for group membership. In addition, no decrement in the ICC was observed for short (1 day) vs longer (1 week) intervals of testing. Conclusions: These performance-based measures may be used reliably across a wider range of testing environments and elderly populations than has been reported.

Repeated measures analysis of geometrically constructed and directly determined cephalometric points

Cephalometric landmarks were directly determined visually from bony anatomy on lateral cephalometric radiographs and compared with geometrically constructed cephalometric landmarks for repeated measures reliability of identification. Three groups of four orthodontists, grouped by level of experience, identified 18 landmarks on each of four cephalometric radiographs. This measurement procedure was repeated four times in 1-week intervals. The variability, main associations and interactions among the variables of tracer experience, quality of radiograph traced, and the anatomic landmarks traced were assessed by means of the repeated measures analysis of variance and follow-up Tukey HSD test. The coefficient of variation was used to compare the relative variability of replicate identification of the 18 cephalometric landmarks. Rank order and statistically significant groupings by variability are listed. The level of observer experience and quality of radiograph were statistically unrelated to landmark variability on replicate examination. The geometrically constructed landmarks tested were not statistically different from the reliability of the directly determined bony-based landmarks. This finding would lend support to the techniques of geometric construction used in the Ricketts cephalometric analysis.