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PubMed2002

Evaluation of measurement strategies to increase the reliability of EMG indices to assess back muscle fatigue and recovery.

The purpose of this study was to assess different measurement strategies to increase the reliability of different electromyographic (EMG) indices developed for the assessment of back muscle impairments. Forty male volunteers (20 controls and 20 chronic low back pain patients) were assessed on three sessions at least 2 days apart within 2 weeks. Surface EMG signals were recorded from four pairs (bilaterally) of back muscles (multifidus at the L5 level, iliocostalis lumborum at L3, and longissimus at L1 and T10) while the subjects performed, in a static dynamometer, two static trunk extension tasks at 75% of the maximal voluntary contraction separated by a 60 s rest period: (1) a 30 s fatigue task and (2) a 5 s recovery task. Different EMG indices (based on individual muscles or averaged across bilateral homologous muscles or across all muscles) were computed to evaluate muscular fatigue and recovery. Intra-class correlation coefficient (ICC) and standard error of measurement (SEM) in percentage of the grand mean were calculated for each EMG variable. Reliable EMG indices are achieved for both healthy and chronic low back pain subjects when (1) electrodes are positioned on medial back muscles (multifidus at the L5 level and longissimus at L1) and (2) measures are averaged across bilateral muscles and/or across two fatigue tests performed within a session. The most reliable EMG indices were the bilateral average of medial back muscles (ICC range: 0.68-0.91; SEM range: 5-35%) and the average of all back muscles (ICC range: 0.77-0.91; SEM range: 5-30%). The averaging of measures across two fatigue tests is predicted to increase the reliability by about 13%. With regards to EMG indices of fatigue, the identification of the most fatigable muscle also lead to satisfactory results (ICC range: 0.74-0.79; SEM range: 21-26%). The assessment of back muscle impairments through EMG analysis necessitates the use of multiple electrodes to achieve reliable results.

Adult↗
PubMed2003

Test-retest reliability of EMG and peak torque during repetitive maximum concentric knee extensions.

The aim of this study was to investigate the reliability of peak torque and surface electromyography (EMG) variable's root mean square (RMS) and mean frequency (MNF) during an endurance test consisting of repetitive maximum concentric knee extensions. Muscle fatigue has been quantified in several ways, and in isokinetic testing it is based on a set of repetitive contractions. To assess test-retest reliability, two sets of 100 dynamic maximum concentric knee extensions were performed using an isokinetic dynamometer. The two series were separated by 7-8 days. The subjects relaxed during the passive flexion phase. Twenty (10 men and 10 women) clinically healthy subjects volunteered. Peak torque and EMG from rectus femoris, vastus medialis, vastus lateralis and biceps femoris were recorded. RMS and MNF were calculated from the EMG signal. The reliability was calculated with intraclass correlation coefficient ICC (1.1) and standard error of measurements (SEM). The reliability of peak torque was good (ICC=0.93) and SEM showed low values. ICC was good for absolute RMS of rectus femoris (ICC>/=0.80), vastus medialis (ICC>/=0.88) and vastus lateralis (ICC>/=0.82) and MNF of rectus femoris (ICC>/=0.82) and vastus medialis (ICC>/=0.83). Peak torque, and MNF and RMS of rectus femoris and vastus medialis are reliable variables obtained from an isokinetic endurance test of the knee extensors.

Adult↗
PubMed2003

Reliability of functional localization using fMRI.

Neuroimaging researchers increasingly take advantage of the known functional properties of brain regions to localize them and probe changes in their activity under different conditions. The utility of this approach depends in part on the reliability of the methods used to define these regions of interest. Two operations may affect the reliability of functionally identified regions: spatially normalizing data to a stereotactic atlas and statistically combining data across participants to form a composite region (as opposed to identifying individual regions for each participant). The effect of these two operations on reliability was evaluated for two functionally identifiable regions: the MT complex and the frontal eye fields. Spatial normalization had almost no effect on within-subject reliability, while grouping across participants negatively affected retest measures of the activation and location of regions defined on separate occasions. We conclude that, for typical sample sizes and numbers of observations per subject, functional localization is most reliable when performed for each individual using data in atlas space.

Adult↗
PubMedDate not supplied

Assessing the reliability and responsiveness of 5 shoulder questionnaires.

The purpose of this study was to compare the test-retest reliability and responsiveness of 5 different shoulder questionnaires in a sample of patients with shoulder pain. Ninety-nine patients completed the following shoulder questionnaires on 2 occasions: Subjective Shoulder Rating Scale, Simple Shoulder Test, Modified-American Shoulder and Elbow Surgeons Form, Shoulder Severity Index, and the Shoulder Pain and Disability Index. The Short Form-36 was also included. Test-retest reliability was assessed with intraclass correlation coefficients. Standardized response means were calculated to assess responsiveness. This procedure was done on 33 subjects who underwent rotator cuff surgery or total shoulder arthroplasty and who believed that they had improved between testings. All questionnaires had acceptable reliability (coefficients > 0.75) except the Subjective Shoulder Rating Scale (coefficient = 0.71) and were more responsive (0.65 < Standardized response mean < 1.23) than the Short Form-36 (0.08 < Standardized response mean < 0.43) except for pain (0.91). In this longitudinal study a direct comparison of 5 shoulder questionnaires was carried out. We found the Subjective Shoulder Rating Scale to have lower reliability and responsiveness. The other 4 questionnaires including 1 developed to measure whole extremity function (Modified American Shoulder and Elbow Surgeons Form) rather than the shoulder only were comparable with good reliability and responsiveness. The results indicate that the shoulder questionnaires were more sensitive to change in patients with shoulder pain than the generic questionnaire (Short Form-36), and both types of questionnaires should be used in outcome evaluations.

Activities of Daily Living↗
PubMedDate not supplied

Reliability of range-of-motion measurement in the elbow and forearm.

The purpose of this study was to examine intratester, intertester, and interdevice reliability of range of motion measurements of the elbow and forearm. Elbow flexion and extension and forearm pronation and supination were measured on 38 subjects with elbow, forearm, or wrist disease by 5 testers. Standardized test methods and a randomized order of testing were used to test groups of patients with universal standard goniometers, a computerized goniometer, and a mechanical rotation measuring device. Intratester reliability was high for all 3 measuring devices. Meaningful changes in intratester range of motion measurements taken with a universal goniometer occur with 95% confidence if they are greater than 6 degrees for flexion, 7 degrees for extension, 8 degrees for pronation, and 8 degrees for supination. Intertester reliability was high for flexion and extension measurements with the computerized goniometer and moderate for flexion and extension measurements with the universal goniometer. Meaningful change in interobserver range of motion measurements was expected if the change was greater than 4 degrees for flexion and 6 degrees for extension with the computerized goniometer compared with 10 degrees and 10 degrees, respectively, if the universal goniometer was used. Intertester reliability was high for pronation and supination with all 3 devices. Meaningful change in forearm rotation is characterized by a minimum of 10 degrees for pronation and 11 degrees for supination with the universal goniometer. Reliable measurements of elbow and forearm arm movement are obtainable regardless of the level of experience when standardized methods are used. Measurement error was least for repeated measurements taken by the same tester with the same instrument and most when different instruments were used.

Adolescent↗
PubMed2000

Assay of prick test inoculum volume. I. Use and reliability of a gamma camera-based method.

INTRODUCTION: In dermatology and allergy there are clinical research circumstances where very small amounts of substances introduced into the skin have to be measured "in vivo." An example is the assay of reagents injected by prick test. As injected volumes are very small, it is necessary to use indicators that can be measured at very low concentrations. In in vitro studies, gamma-emitting radioisotopes have been shown suitable for use as the indicators. In in vivo studies, except for instruments devised for specific research requirements, the measurement of small sources is taken with a common gamma camera. OBJECTIVE: The purpose of the present study is to evaluate the experimental reliability of a gamma camera-based method to measure microvolumes labeled with radioisotopes and its suitable application in vivo studies. METHODS: Using a solution of 99m Tc-pertechnetate, we prepared, with precision pipettes, some sets of scalar volumes ranging from 1 micro to 200 picoliters, which correspond to activities between some micros and some hundreds of picocuries. The volumes were measured with a gamma camera both with and without a collimator. The overall reliability of the method under different experimental conditions was evaluated for sensitivity, precision, and accuracy. Last, a blind measurement was taken as a final check on the overall reliability of the method. RESULTS: The volume-activity correlation appeared to be linear, with a Spearman coefficient higher than 0.99. The correlation straight lines of the measurements taken with and without a collimator proved that, in both cases, the linearity of the system did not change. The method showed a high degree of precision and accuracy. The maximum variation coefficient never exceeded 1.5% and the standard error 2%. The sampling error of the measured volumes was less than 8% in all the sets: up to 7% was due to the manual operations and to the technical characteristics of the micropipettes. The gamma camera measurement error ranged from 1% to 3%. The blind tests experimentally confirmed the overall reliability of the method. CONCLUSIONS: The method we studied proved highly reliable and inexpensive. Measurement errors are almost exclusively due to sampling errors. The gamma camera is a device any nuclear medicine department is equipped with, and a solution of 99m Tc-pertechnetate is readily available.

Evaluation Studies as Topic↗
PubMed2002

[Reliability of global interdigital pinch (vice pinch) dynamometral values measured by Microfet 2].

OBJECTIVE: To study test-retest reliability of pinch grip strength with a two-month gap in three upper limb positions. To study factors causing variability of peak force. MATERIAL AND METHODS: Forty healthy control volunteers, sex-ratio 1, mean age 36.6 years (sd = 9.9), were separated into four groups of ten persons. The Microfet 2 dynamometer was used to measure peak force developed during pinch grip. The measurements were made in three positions: upper limb parallel to body, arm flexed at 90 degrees and during the Roos manoeuvre. Test-retest reliability was evaluated after two months. Statistical analysis used the correlation test (p = 0.05). RESULTS: Reliability proved to be excellent in all three positions and in all four groups. Dynamometer values were stable between the beginning and end of the Roos manoeuvre in this healthy population. There were no significant differences between peak force measured in the three positions and between left and right upper limbs. DISCUSSION: The Roos manoeuvre gives a stable and reliable result in a population without thoracic outlet syndrome. Dynamometer tests are also reliable in the usual upper limb positions, in accordance with other studies. CONCLUSION: This dynamometric test should be useful in assessing the severity of thoracic outlet syndrome and in demonstrating the therapeutic efficacy of different treatments.

Adult↗
PubMed2005

Design, format, validity and reliability of multiple choice questions for use in nursing research and education.

Multiple choice questions are used extensively in nursing research and education and play a fundamental role in the design of research studies or educational programs. Despite their widespread use, there is a lack of evidence-based guidelines relating to design and use of multiple choice questions. Little is written about their format, structure, validity and reliability of in the context of nursing research and/or education and most of the current literature in this area is based on opinion or consensus. Systematic multiple choice question design and use of valid and reliable multiple choice questions are vital if the results of research or educational testing are to be considered valid. Content and face validity should be established by expert panel review and construct validity should be established using 'key check', item discrimination and item difficulty analyses. Reliability measures include internal consistency and equivalence. Internal consistency should be established by determination of internal consistency using reliability coefficients while equivalence should be established using alternate form correlation. This paper reviews literature related to the use of multiple choice questions, current design recommendations and processes to establish reliability and validity, and discusses implications for their use in nursing research and education.

Education, Nursing↗
PubMed2002

What determines visual cue reliability?

Visual environments contain many cues to properties of an observed scene. To integrate information provided by multiple cues in an efficient manner, observers must assess the degree to which each cue provides reliable versus unreliable information. Two hypotheses are reviewed regarding how observers estimate cue reliabilities, namely that the estimated reliability of a cue is related to the ambiguity of the cue, and that people use correlations among cues to estimate cue reliabilities. Cue reliabilities are shown to be important both for cue combination and for aspects of visual learning.

Journal Article↗
PubMed1999

Reliability of surface electromyographic measurements.

OBJECTIVES: The aim of the study was to investigate short-term, intermediate-term and long-term reliability of surface electromyographic (EMG) measurements. METHODS: Eighteen healthy subjects performed 810 isometric knee extension tests. Reliability for maximum voluntary contraction (MVC) and 50% MVC was assessed with retest intervals of 3 min, 90 min and 6 weeks. Reliability for sustained contractions was assessed with retest intervals of 90 min and 6 weeks. EMG was recorded from the rectus femoris, vastus lateralis and vastus medialis muscles. The root mean square (RMS) and the median frequency (MF) parameters were extracted. At sustained contraction tasks, estimated linear regression values of both parameters were analyzed. Bland-Altman-plots, coefficient of repeatability, Pearson's coefficient of correlation and intra class correlation (ICC) procedures were applied to assess test-retest reliability. RESULTS: EMG recordings taken at short-term intervals were generally better reproducible than those of the longer-term intervals. Moreover, 50% MVC EMG recordings demonstrated better reproducibility than 100% MVC measurements, and EMG recorded from the rectus femoris were more constant than that from the vastus lateralis or vastus medialis. The MF parameter recorded from the rectus femoris was the only reliable parameter of EMG fatigue change. CONCLUSION: In our set up, EMG measurement is best suited for clinical applications if submaximal MVC measurements are performed and signal is taken from rectus femoris muscle.

Adult↗
PubMed2003

Test-retest reliability of the aerobic power index component of the tri-level fitness profile in a sedentary population.

Use of maximal aerobic power (VO2(max)) testing, which requires subjects to exercise to physiological limits, may deter eligible candidates from volunteering for trials and may also be contraindicated in patients suffering from various medical illnesses. An alternative to maximal testing is submaximal testing. The Aerobic Power Index, which represents the aerobic component of the Tri-level Fitness Profile, is a submaximal test that has been shown to be reliable in trained athletes. The purpose of this study was to establish reliability of the Aerobic Power Index, as well as associated variables of VO2 (ml x kg(-1) x min(-1) and rate of perceived exertion (RPE), in a group of sedentary subjects. Results for the 20 subjects who participated in a test-retest trial indicated high reliability (ICC r = 0.98, %TEM 3.87 W x kg(-1); SEM 0.04 W x kg(-1) for the main measurement outcome of Watts per kilogram (W x kg(-1)). Oxygen uptake (ml x kg(-1)min(-1)) also demonstrated high reliability (ICC r = 0.92; %TEM 4.63 ml x kg(-1) x min(-1); SEM 0.58 ml x kg(-1) min (-1), as did RPE (ICC r = 0.97,%TEM 7.78; SEM 0.63). Limits of agreement were -0.02+/-0.16 W x kg(-1). -0.41+/-2.31 ml x kg(-1) x min(-1) for VO2 and -0.05 < or = 2.10 for RPE. These results indicate that the Aerobic Power Index is a reliable submaximal exercise test for use in sedentary subjects.

Adult↗
PubMed2000

The use of visual analogue scales to assess motivation to eat in human subjects: a review of their reliability and validity with an evaluation of new hand-held computerized systems for temporal tracking of appetite ratings.

This present paper reviews the reliability and validity of visual analogue scales (VAS) in terms of (1) their ability to predict feeding behaviour, (2) their sensitivity to experimental manipulations, and (3) their reproducibility. VAS correlate with, but do not reliably predict, energy intake to the extent that they could be used as a proxy of energy intake. They do predict meal initiation in subjects eating their normal diets in their normal environment. Under laboratory conditions, subjectively rated motivation to eat using VAS is sensitive to experimental manipulations and has been found to be reproducible in relation to those experimental regimens. Other work has found them not to be reproducible in relation to repeated protocols. On balance, it would appear, in as much as it is possible to quantify, that VAS exhibit a good degree of within-subject reliability and validity in that they predict with reasonable certainty, meal initiation and amount eaten, and are sensitive to experimental manipulations. This reliability and validity appears more pronounced under the controlled (but more artificial) conditions of the laboratory where the signal:noise ratio in experiments appears to be elevated relative to real life. It appears that VAS are best used in within-subject, repeated-measures designs where the effect of different treatments can be compared under similar circumstances. They are best used in conjunction with other measures (e.g. feeding behaviour, changes in plasma metabolites) rather than as proxies for these variables. New hand-held electronic appetite rating systems (EARS) have been developed to increase reliability of data capture and decrease investigator workload. Recent studies have compared these with traditional pen and paper (P&P) VAS. The EARS have been found to be sensitive to experimental manipulations and reproducible relative to P&P. However, subjects appear to exhibit a significantly more constrained use of the scale when using the EARS relative to the P&P. For this reason it is recommended that the two techniques are not used interchangeably.

Appetite↗
PubMed2006

Reliability of the manual ability classification system for children with cerebral palsy.

The aim of this study was to determine the reliability of family and professional assessment of manual ability using the Manual Ability Classification System (MACS) for children with cerebral palsy (CP) in the UK. Families who were taking part in a study measuring the activities and participation of children with CP were invited to classify their child's manual ability using the MACS. Postal surveys were conducted with the families and health professionals nominated by the families. Perfect agreement was assessed as a percentage; chance-corrected agreement was measured using Cohen's kappa (kappa), and reliability was determined using the intraclass correlation coefficient (ICC). Families of 91/128 (71%) children responded to the survey (53 males, 38 females; mean age 9y 11mo [SD 1y 11mo], range 6-12y) out of whom 88 indicated a single MACS level. Seventy-two children (82%) were classified with spastic CP, 12 (14%) with dyskinesia, two (2%) with ataxia, and two (2%) were not classified. There were 21, 27, 11, 10, and 19 children who were classified by their families in Gross Motor Function Classification System Levels I to V respectively; 14, 30, 18, 13, and 13 children classified by their families in MACS levels I to V. The survey of health professionals generated 60/71 (85%) responses from physiotherapists, 55/58 (93%) responses from paediatricians, and 21/24 (88%) responses from occupational therapists. There was perfect agreement between families and professionals for more than 50% of children; the indices of chance-corrected agreement ranged from kappa=0.3 to 0.5, and the reliability coefficients ranged from ICC 0.7 to 0.9. Indices of agreement and reliability between families and professionals were equivalent to those between different professionals. The MACS, therefore, offers a valid and reliable method for communicating about the manual ability of children with CP. Families and professionals may not always agree precisely on a MACS level, particularly if children's performance of manual tasks varies in different environments.

Aptitude↗
PubMed1979

Comparative reliability of categorical and analogue rating scales in the assessment of psychiatric symptomatology.

The reliability of 26 items from the ninth edition of the Present State Examination (PSE) was assessed using both the conventional categorical scales and separately constructed analogue scales. Reliability was also calculated when the analogue responses were rescaled down to 2, 3 and 4 categories. The levels of inter-rater agreement obtained were comparable to those achieved in previous studies of PSE reliability, although as expected the levels of agreement on audiotapes were greater than those for independent interviews performed on the same day. These levels were not significantly affected by any of the changes in scale format, but there were apparent differences in reliability depending on the statistics used. In selecting or constructing a psychiatric rating scale, the question of reliability should not influence the choice of a categorical or continuous scale, or the number of scored points in the scale.

Psychiatric Status Rating Scales↗
PubMed2001

Are there sex differences in the reliability of a lifetime history of major depression and its predictors?

BACKGROUND: Although lifetime major depression (LTMD) is assessed with only moderate reliability in community samples, some predictors have emerged for 'reliable' LTMD. Given the large impact of sex on risk for LTMD, it is of interest to know if there are sex differences in the reliability of LTMD and its predictors. METHODS: A total of 5603 members of male-male and male-female twin pairs from a population-based registry were interviewed twice with a mean inter-interview interval of 19 months. LTMD was assessed on each occasion using DSM-III-R criteria. Univariate and multivariate logistic regression analyses were used, combining forward and back-prediction. RESULTS: The long-term test-retest reliability of LTMD was moderate (kappa = +0.48) and did not differ significantly between males and females. In a multivariate model, the significant predictors of a stable diagnosis of LTMD, none of which differed across sex, were younger age at onset, older current age, history of treatment, increasing number of symptoms, level of impairment or level of distress, longer duration of episodes, higher current level of depression and the presence during the depressive episode of sad mood, weight loss, hypersomnia or fatigue. Using these variables, it was not possible to predict 'stably diagnosed' LTMD with both high sensitivity and high specificity. CONCLUSION: In community samples, LTMD is diagnosed with moderate reliability. Although diagnostic stability can be predicted by variables related to severity, distress and treatment-seeking (probably acting to make depressive episodes more 'memorable'), highly accurate prediction of stably diagnosed cases is not possible. Long-term recall is also significantly influenced by current symptoms. Neither the stability of LTMD nor its predictors differ in men and women.

Adult↗
PubMed2005

Test-retest reliability of health utilities index scores: evidence from hip fracture.

OBJECTIVES: There is relatively little evidence on the test-retest reliability of utility scores derived from multiattribute measures. The objective was to estimate test-retest reliability for Health Utilities Index Mark 2 (HUI2) and Mark 3 (HUI3) utility scores in patients recovering from hip fracture. METHODS: We enrolled an inception cohort of hip fracture patients within 3 to 5 days of surgery. Baseline assessments included the Functional Independence Measure (FIM), Folstein Mini-Mental State Examinations, and the HUI2 and HUI3 questionnaire. Follow-up assessments at 1, 3, and 6 months also included a global change question. Test-retest reliability was assessed as agreement between 3- and 6-month scores using the intraclass correlation coefficient (ICC). Two approaches were used to classify patients as stable; a third approach based on the generalizability theory was also used. Patients were classified as stable if their FIM overall scores changed by 10 points or fewer and if they classified themselves as having experienced no or only a little change according to their global change question. RESULTS: Complete data at both the 3- and 6-month assessments based on self-report were available for 196 patients; 141 patients with complete data were classified as stable. The ICCs for HUI2 and HUI3 for stable patients were 0.71 and 0.72; the ICCs derived from the generalizability theory were 0.76 and 0.77. CONCLUSIONS: Test-retest reliability for HUI in this cohort was similar to reliability estimates for other preference-based multiattribute and generic health-profile measures--in the acceptable range for making valid group-level comparisons.

Aged↗
PubMed1996

Reliability of the Modified Ordinal Scales of Psychological Development: a cognitive assessment battery for severe dementia.

Two reliability studies were performed on a recently developed cognitive assessment battery for severe dementia. The method, the Modified Ordinal Scales of Psychological Development (M-OSPD), is based on the Piagetian developmental model of sensorimotor functions. Procedures have been adapted from this test battery, which was originally applied to infants and small children, for the assessment of remaining cognitive capacity in severe dementia. Two independent interrater reliability studies were conducted. In these studies, two different raters simultaneously evaluated patients with severe dementia. One interrater reliability study was performed in a nursing home setting (Study 1), and the other reliability study consisted of a sample of community-residing patients (Study 2). The Global Deterioration Scale and the Mini-Mental State Examination were used to assess dementia severity. Study 1 (N = 22) resulted in an intraclass correlation coefficient (ICC) of .99 (p < .01) for the M-OSPD total score. Study 2 (N = 19) resulted in an ICC of .96 (p < .01) for the M-OSPD total score. The M-OSPD proved to be a reliable instrument in these studies. This cognitive assessment measure can provide meaningful information regarding the cognitive abilities of late-stage dementia patients. Until recently, these late-stage dementia patients had been considered untestable in studies that utilized conventional psychometric and mental status evaluation measures.

Aged↗
PubMed1999

Reliability and validity of the subjective burden scale in family caregivers of elderly relatives with dementia.

The reliability and validity of the Subjective Burden Scale (SBS) were investigated in 255 Japanese family caregivers of elderly relatives with dementia. Values of the Cronbach's alpha reliability, split-half reliability (r), and test-retest reliability (r) were .87, .80, and .72, respectively. The SBS score was significantly positively correlated with the degree of mental health, which was assessed with the Japanese version of the 60-item General Health Questionnaire (r = .41). The family caregivers who gave up the caregiving of their relatives showed significantly higher SBS scores than those who did not. The SBS scores for caregivers indicated satisfactory predictive validity both in the degree of their mental health and in the prospects of family caregiving about 6 months later. These findings suggest that the SBS is adequately reliable and valid and can be used to assess the subjective burden of Japanese caregivers.

Aged↗