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PubMed2003

Interrater reliability of clinical examination measures for identification of lumbar segmental instability.

OBJECTIVE: To determine the interrater reliability of common clinical examination procedures proposed to identify patients with lumbar segmental instability. DESIGN: Single group repeated-measures interrater reliability study. SETTING: Outpatient physical therapy (PT) clinic and university PT department. PARTICIPANTS: A consecutive sample of 63 subjects (38 women, 25 men; 81% with previous episodes of low back pain [LBP]) with current LBP was examined by 3 pairs of raters. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Repeat measurements of clinical signs and tests proposed to identify lumbar segmental instability. RESULTS: Kappa values for the trunk range of motion (ROM) findings varied (range,.00-.69). The prone instability test (kappa=.87) showed greater reliability than the posterior shear test (kappa=.22). The Beighton Ligamentous Laxity Scale (LLS) for generalized ligamentous laxity showed high reliability (intraclass correlation coefficient=.79). Judgments of pain provocation (kappa range,.25-.55) were generally more reliable than judgments of segmental mobility (kappa range, -.02 to.26) during passive intervertebral motion testing. CONCLUSIONS: The results agree with previous studies suggesting that segmental mobility testing is not reliable. The prone instability test, generalized LLS, and aberrant motion with trunk ROM demonstrated higher levels of reliability.

Adult↗
PubMed1995

Psychological measures: reliability in the assessment of stroke patients.

OBJECTIVE: To determine whether acute stroke patients can give reliable responses to standardized psychological measures. DESIGN: Survey design with retrospective review of Neurobehavioral Cognitive Status Examination (NCSE) scores. SETTING: A rehabilitation hospital in Philadelphia. PATIENTS: 106 consecutive admissions to stroke services at a rehabilitation hospital were evaluated according to the following inclusion criteria: Patients at least 65 years of age, English speaking, having a documented history of cerebrovascular accident (CVA), possession of receptive speech comprehension, and the ability to maintain attention adequate for participation in the study interview. Of the 47 eligible for participation, 10 patients refused participation and 13 were discharged before the interview could be completed. Thus 24 patients were interviewed, with one patient unable to complete the second half of the interview. MAIN OUTCOME MEASURES: In phase 1, the patient's performance on a structured interview (including the Multidimensional Health Locus of Control Scales (MHLC), Life Orientation Test (LOT), and Center for Epidemiological Studies Depression Scale (CES-D) scales) produced a Total Reliability Score, indicating the overall reliability of the patient's responses. In phase 2, NCSE scores were examined (retrospectively) for their ability to predict the patient's Total Reliability Score on the structured interview. RESULTS: Using Total Reliability Scores, 9 patients were categorized as "passing," 9 were categorized as "uncertain," and 5 were categorized as "failing" the interview. The NCSE was predictive for individuals who had a very low likelihood of being able to respond consistently. The NCSE failed to identify which individuals would respond in a reliable fashion. CONCLUSIONS: It is both possible and important to assess response reliability when using psychological measures soon after stroke. Future research will need to document other potential predictors of interview performance, including combinations of NCSE subscales.

Aged↗
PubMed1997

Cumulative trauma disorders in the upper extremities: reliability of the postural and repetitive risk-factors index.

OBJECTIVE: This study addresses test-retest reliability of the Postural and Repetitive Risk-Factors Index (PRRI) for work-related upper body injuries. This assessment was developed by the present authors. DESIGN: A repeated measures design was used to assess the test-retest reliability of a videotaped work-site assessment of subjects' movements. SUBJECTS: Ten heavy users of video display terminals (VDTs) from a local banking industry participated in the study. SETTING: The 10 subjects' movements were videotaped for 2 hours on each of 2 separate days, while working on-site at their VDTs. MAIN OUTCOME MEASURE: The videotaped assessment, which utilized known postural risk factors for developing musculoskeletal disorder, pain, and discomfort in heavy VDT users (ie, repetitiveness, awkward and static postures, and contraction time), was called the PRRI. The videotaped movement assessments were subsequently analyzed in 15-minute sessions (five sessions per 2-hour videotape, which produced a total of 10 sessions over the 2 testing days), and each session was chosen randomly from the videotape. The subjects' movements were given a postural risk score according to the criteria in the PRRI. Each subject was therefore tested a total of 10 times (ie, 10 sessions), over two days. The maximum PRRI score for both sides of the body was 216 points. RESULTS: Reliability coefficients (RCs) for the PRRI scores were calculated, and the reliability of any one session met the minimum criterion for excellent reliability, which was .75. A two-way analysis of variance (ANOVA) confirmed that there was no statistically significant difference between sessions (p < .05). Calculations using the standard error of measurement (SEM) indicated that an individual tested once, on one day and with a PRRI score of 25, required a change of at least 8 points in order to be confident that a true change in score had occurred. The significant results from the reliability tests indicated that the PRRI was a reliable measurement tool that could be used by occupational health practitioners on the job site.

Adult↗
PubMed1997

The Arm Motor Ability Test: reliability, validity, and sensitivity to change of an instrument for assessing disabilities in activities of daily living.

OBJECTIVE: To continue and expand determination of the reliability, validity, and sensitivity to change of the Arm Motor Ability Test (AMAT), an instrument for assessing deficits in activities of daily living (ADL). DESIGN: The AMAT was administered twice to patients, with an interest interval of either 1 or 2 weeks, by one of two examiners assigned to patients in counterbalanced order. Patients' interest intervals and scores on the arm portion of the Motricity Index was unknown to the raters. SETTING: A referral inpatient neurological rehabilitation center. PATIENTS: Thirty-three subacute stroke inpatients with moderate to mild upper extremity motor deficit: median Motricity-Index-Arm score = 89, median chronicity = 43d, median age = 66yr; 12 were women. MAIN OUTCOME MEASURE AND RESULTS: The AMAT was developed in 1987, and interrater reliabilities at that time were found to range from .95 to .99. The present values for interrater reliability (2 scales) from videotaped test performance were: kappas = .68 to .77. Spearman correlations = .97 to .99. For performance time, interscorer reliability from videotaped test performance was .99. Homogeneities for the three AMAT measures for the total sample (Cronbach's alpha and split-half reliability) were .93 to .99. The test-retest reliabilities for the total sample were .93 to .99. The correlations to the Motricity-Index-Arm score were .45 to .61. The AMAT detected the difference in change occurring as a result of the passage of 1 versus 2 weeks in these subacute inpatients, presumably as a result of intensive therapy and/or spontaneous recovery, confirming the results of an earlier intervention study. CONCLUSION: The AMAT is an instrument with high interrater reliability, internal consistency, and sensitivity to change, as well as having satisfactory concurrent validity.

Activities of Daily Living↗
PubMed2000

High internight reliability of computer-measured NREM delta, sigma, and beta: biological implications.

BACKGROUND: Computer analysis of the sleep electroencephalogram (EEG) waveforms is widely employed, but there have been no systematic studies of its reliability. METHODS: The most commonly used computer methods are power spectral analysis with the fast-Fourier transform (FFT) and period amplitude analysis (PAA) with zero cross or zero first derivative half-wave measurement. We applied all three computer methods to the digitized EEG of 16 normal subjects who underwent 5 consecutive nights of baseline (placebo) recording. We evaluated the internight reliability of three non-rapid eye movement (NREM) frequency bands of special importance to sleep research: delta (0.3-3 Hz), sigma (12-15 Hz), and beta (15-23 Hz). RESULTS: Both FFT and the two methods of PAA gave excellent internight reliability for delta and sigma. Even a single night of recording correlated highly (r >.9) with the 5-night mean. Beta reliability was lower but still highly significant for both the PAA and the FFT measures. CONCLUSIONS: Computer-analyzed sleep EEG data are highly reliable. Period amplitude methods demonstrate that wave incidence and period as well as amplitude are reliable, indicating that the reliability of composite measures (FFT power, PAA integrated amplitude) is not solely based on individual differences in EEG amplitude. The high internight stability of NREM delta indicates that it possesses traitlike characteristics and is relatively independent of day-to-day variations in state.

Adult↗
PubMed2003

PulStar differential compliance spinal instrument: a randomized interexaminer and intraexaminer reliability study.

OBJECTIVE: To provide an entry-level, new technology reliability assessment of the PulStar computer-assisted, differential compliance spinal instrument. SUBJECTS: Eighteen college students (9 male and 9 female) were recruited by announcements and personal contacts. METHODS: Following approval of the consent process by the Institutional Review Board of Mississippi State University, a PulStar Function Recording and Analysis System (PulStarFRAS) device was evaluated for clinical reliability. Two examiners, blinded from data collection, used the instrument on individual subjects in random order (lying prone with their backs exposed) to administer light impulses (approximately equal to .9 J which produced a 3- to 4-lb force) at each segmental level throughout the cervical, dorsal, and lumbar spine using probe tips spaced 3 cm apart, straddling the spinous processes, while a computer recorded the findings (resistance on a scale of 0 to 25.5 lb force). Data were analyzed by Exploratory Data Analysis (EDA) with analysis of variance (ANOVA) testing and by use of the intraclass correlation coefficient (ICC). In addition, a mean test (ANOVA) was conducted to determine if a trend in variation occurred as a result of repeated light thrusts to the spine, independent of variance explained by different examiners. RESULTS: Using EDA analysis and ANOVA, intraexaminer reliability for the 2 practitioners was very high but not perfect. This was confirmed by ICC statistics demonstrating good to excellent reliability for both practitioners (0.89 for the experienced practitioner, 0.78 for the newly trained practitioner). Interexaminer reliability of PulStar was similarly very high but not perfect based on EDA/ANOVA analysis and good to excellent (ICC = 0.87). CONCLUSION: The PulStar mechanical adjusting device set to analysis mode appears to have good to excellent reliability when used by either an experienced or a novice (but trained) examiner. In addition, as a measure for resistance to a light thrust or spinal compliance, reliability was similarly good to excellent between the 2 doctors using the PulStar instrument.

Adult↗
PubMed1996

A multirater validation study to assess the reliability of acne lesion counting.

BACKGROUND: Despite widespread use of acne lesion counting, little has been published on its reliability, particularly for multiple raters. OBJECTIVE: Our purpose was to assess reliability of acne lesion counting with the use of a five-segment facial template. METHODS: After training, 12 raters each evaluated 12 patients in randomized order, in the morning and again in the afternoon, and recorded counts for different types of lesions on a five-segment facial template. RESULTS: Individual raters could reproduce their total lesion counts (reliability estimates, 0.81 to 0.97). Variability between raters was high, and overall reliability estimated across raters was 0.61. For a subgroup of commonly trained raters, overall reliability was higher (0.80). CONCLUSION: The reliability of acne lesion counting is excellent when performed by the same trained rater over time. The high variability between raters appears to be reduced by standardized training. Because fewer lesions are counted with less variation, use of a template may have contributed to the high within-rater reliability.

Acne Vulgaris↗
PubMed2003

Reliability and accuracy of different sensors of a flexible electrogoniometer.

OBJECTIVE: To describe a gauging device for electrogoniometer sensors and to evaluate the reliability and accuracy of different sensors including two similar sensors. DESIGN: Repeated measurement design for reliability. BACKGROUND: Despite being considered reliable equipment, several aspects of electrogoniometer reliability and accuracy have not been reported so far. METHOD: Five repeated measurements of each electrogoniometer sensor were performed in 1 degrees increments, during the whole uniplanar amplitudes of flexion, extension, lateral deviations and rotational movements, totaling 6380 measurements. RESULTS: Values from the coefficient of variation and mean square error, respectively indicated that the reliability and accuracy of the sensors varied between sensors and movements, with goniometers being more reliable and accurate than torsiometers. A significant difference between identical sensors was identified. CONCLUSIONS: No similar pattern of variation was found between the sensors evaluated, indicating that every sensor should be tested for its reliability and accuracy when highly precise measurements are needed, and particularly when bilateral limbs are being compared. RELEVANCE: Research on movement recordings demands precise methodology for quantifying angular variations.

Calibration↗
PubMed2003

[Reliability of a questionnaire on smoking to evaluate prevalence, knowledge and attitudes of medical students].

OBJECTIVE: To evaluate the reliability and reproducibility of results obtained from a questionnaire on the smoking habits of medical students. METHOD: A questionnaire with 30 variables was designed to measure three main parameters: prevalence, knowledge and attitudes toward smoking. First-year medical students at the University of Zaragoza (1997-98 academic year) were asked to fill in the questionnaire, and a code was assigned to each individual respondent. A test-retest method was then used to assess reliability: the same questionnaire was answered by the subjects after a period of time had elapsed. The Kappa coefficient was calculated to measure agreement. RESULTS: The questionnaire was filled in by 181 students at registration and 7 weeks later by 43 students. The first- and second-time questionnaires for 35 individuals were matched by codes. Reliability was good for most variables related to the main characteristics of smoking (such as prevalence, number of cigarettes smoked daily and consonance-dissonance). Reliability was acceptable for most variables related to knowledge but was low for 3 items. Reliability was acceptable for half the items related to attitudes and low for half. CONCLUSIONS: The questionnaire has a generally good level of reliability, with regard to reproducibility, or the likelihood that an individual will respond to an item in the same way at two different times. Some variables that measure attitudes toward smoking, however, are less reliable. Results obtained for those items should therefore be interpreted cautiously.

Adult↗
PubMed2001

Dissection and weighing of accessory sex glands after formalin fixation, and a 5-day assay using young mature rats are reliable and feasible in the Hershberger assay.

The rodent Hershberger assay has been used predominantly by the pharmaceutical industry to evaluate androgenic and antiandrogenic chemicals for potential therapeutic use. However, this assay has not yet been formally validated and standardized for use in toxicology testing. There are many variations in the protocol used for this assay. The weight of androgen-dependent tissues is a definitive endpoint in the Hershberger assay. To find out the reliable assay protocol with feasibility, although many possible factors may affect assay reliability, the present study consist of a series of three separate experiments focused on method of dissection and weighing of accessory sex glands (ASGs: ventral and dorso-lateral prostate, seminal vesicles together with coagulating glands, and Cowper's glands), animal age and number of doses. Furthermore, male pubertal assay, an alternative to the Hershberger assay, was also examined its reliability. Experiment 1 explored whether reliably accurate ASG weights can be obtained after formalin fixation. The ASGs were collected from castrated male rats (11 weeks of age) treated daily with corn oil, or testosterone propionate (TP, 0.25 mg/kg/day, s.c.) and p,p'-DDE (0 or 100 mg/kg/day, p.o.) for 5 days. One day after the final treatment, the ASGs were removed carefully and weighed separately, and then fixed overnight in a 10% neutral-buffered formalin and weighed again. After that, the tissues were dried overnight in an oven and weighed again. A high correlation between fresh and fixed tissue weights, and a high correlation between fixed and dried tissue weights were noted. The changes in the tissue weight due to fixation were marginal and were proportional to the fresh weights of the individual tissue. Standard deviation of the fixed tissue weight in each group and the magnitude of responses to TP or p,p'-DDE in fixed tissues were equivalent to those in fresh or dried tissues. These findings indicate that formalin fixation does not interfere with interpretation of assay results, and this procedure was used in the subsequent experiments. Experiments 2 and 3 explored whether animal age or treatment duration altered assay sensitivity. In Experiment 2, antiandrogenic effect of p,p'-DDE (100 mg/kg/day) was detected after 5-and 10-day treatment irrespective of animal age (7 vs 11 weeks). In Experiment 3, antiandrogenic effects of flutamide (1 and 10 mg/kg/day) and p,p'-DDE (10 and 100 mg/kg/day) were compared between two different protocols, the 10-day assay using peripubertal rats and the 5-day assay using young mature rats. Results demonstrated that both protocols could significantly detect antiandrogenic effects of flutamide and p,p'-DDE. These findings demonstrate that (1) dissection and weighing of ASGs after formalin fixation is reliable in the Hershberger assay, (2) when this procedure is used, the 5-day Hershberger assay using young mature rats, expected to be more feasible assay than the 10-day assay using peripubertal rats, is also reliable as well as the 10-day assay using peripubertal rats. Furthermore, we confirmed that male pubertal assay with use of dissection and weighing of fixed tissues also reliable.

Androgens↗
PubMed1997

WHO Study on the reliability and validity of the alcohol and drug use disorder instruments: overview of methods and results.

The WHO Study on the reliability and validity of the alcohol and drug use disorder instruments in an international study which has taken place in centres in ten countries, aiming to test the reliability and validity of three diagnostic instruments for alcohol and drug use disorders: the Composite International Diagnostic Interview (CIDI), the Schedules for Clinical Assessment in Neuropsychiatry (SCAN) and a special version of the Alcohol Use Disorder and Associated Disabilities Interview schedule-alcohol/drug-revised (AUDADIS-ADR). The purpose of the reliability and validity (R&V) study is to further develop the alcohol and drug sections of these instruments so that a range of substance-related diagnoses can be made in a systematic, consistent, and reliable way. The study focuses on new criteria proposed in the tenth revision of the International Classification of Diseases (ICD-10) and the fourth revision of the diagnostic and statistical manual of mental disorders (DSM-IV) for dependence, harmful use and abuse categories for alcohol and psychoactive substance use disorders. A systematic study including a scientifically rigorous measure of reliability (i.e. 1 week test-retest reliability) and validity (i.e. comparison between clinical and non-clinical measures) has been undertaken. Results have yielded useful information on reliability and validity of these instruments at diagnosis, criteria and question level. Overall the diagnostic concordance coefficients (kappa, kappa) were very good for dependence disorders (0.7-0.9), but were somewhat lower for the abuse and harmful use categories. The comparisons among instruments and independent clinical evaluations and debriefing interviews gave important information about possible sources of unreliability, and provided useful clues on the applicability and consistency of nosological concepts across cultures.

Adult↗
PubMed2003

Test-retest reliability of a questionnaire on physical activity and its correlates among women from diverse racial and ethnic groups.

BACKGROUND: A better understanding of physical activity and its correlates is needed, especially among diverse populations of women. The objective of this study was to examine the test-retest reliability of a survey designed to measure physical activity and its correlates among women from diverse racial and ethnic groups. METHODS: Test and retest surveys were conducted in person or over the telephone with 344 white, Latina, African-American, and Native American women aged 20 to 50 years living in rural and urban areas of the United States. Reliability of self-reported physical activity and its correlates were determined using intraclass correlation coefficients (ICC) overall and separately by site and race/ethnicity. RESULTS: Of the women responding, 45% of the participants met recommendations for physical activity, 40% were insufficiently active, and 15% were inactive. Reliability for the physical activity measure was 0.69 (95% confidence interval [CI], 0.62-0.74), with an ICC of 0.30 to 0.95 across sites. Overall, the seven items on the physical environment had substantial reliability (ICC=0.64-0.91). The sense of community scale (0.79; 95% CI, 0.74-0.83), social issues (0.68; 95% CI, 0.61-0.74), social roles (0.64; 95% CI, 0.56-0.71), and self-efficacy for exercise (0.72; 95% CI, 0.66-0.77) all had acceptable reliability overall and across most sites. CONCLUSIONS: This study provides psychometric evidence that the questionnaire on physical activity and its correlates is reliable among diverse women aged 20 to 50 years from various racial and ethnic groups. These results suggest that test-retest reliability is not an obstacle to comparison of associations between physical activity and several hypothesized correlates of activity.

Adult↗
PubMed2001

Reproducibility of optical biometry using partial coherence interferometry : intraobserver and interobserver reliability.

PURPOSE: To evaluate the intraobserver and interobserver variability in axial length (AL), anterior chamber depth (ACD), and corneal radius measurements using an optical biometry instrument based on partial coherence interferometry (PCI). SETTING: Johannes Gutenberg University, Mainz, Germany. METHODS: In this observational case series and interobserver reliability trial, 30 healthy, emmetropic to moderately myopic eyes of 15 volunteers were evaluated. The AL, ACD, and corneal radius were measured 20 times in 10 eyes by 1 observer to evaluate the intraobserver variability. To evaluate the interobserver variability, the measurements were taken in 20 eyes by 5 different observers. Measurements were performed using the IOLMaster (Carl Zeiss) based on PCI. The data description is based on coefficients of variation and the statistical inference on reliability estimation based on analysis of variance. The main outcome measures were intraobserver and interobserver variability and reliability in AL, ACD, and corneal radii. RESULTS: The intraobserver variability (SD) was +/-25.6 microm for AL, +/-33.4 microm for ACD, and +/-12.9 microm for corneal radius. The coefficients of variation were 0.1%, 0.9%, and 0.17%, respectively. The interobserver variability (SD) was +/-21.5 microm for AL, +/-29.8 microm for ACD, and +/-15.9 microm for corneal radius. The coefficients of variation were 0.09%, 0.82%, and 0.21%, respectively. The reliability was 99.9% for AL, 97.8% for ACD, and 99.8%/99.5% for corneal radius (r1/r2). The slightly reduced reliability in ACD measurement was caused by a reduced intraobserver reliability of 1 of the 5 observers (R = 0.87). CONCLUSION: Partial coherence biometry using the IOLMaster for AL measurement was highly reliable, offering observer-independent measurement results.

Adult↗
PubMedDate not supplied

Reliability of blood pressure, heart rate, and Doppler-derived hemodynamic measurements during exercise.

Doppler echocardiography of aortic blood flow, heart rate, and blood pressure represent noninvasive methods for evaluation of the hemodynamic effects of pharmacologic agents or other stimuli during rest and exercise. In this study the reliability of continuous-wave Doppler echocardiography for detecting the effects of various interventions on left ventricular systolic function during exercise was assessed. The reliability of Doppler measurements was compared with that found for measurements of simultaneously obtained heart rate and blood pressure. Exercise treadmill testing was performed at 0, 2, 4, 6, and 8 hours in 18 healthy male subjects. All measurements were performed at rest and during the last half of each exercise stage. Reliability of peak modal velocity, peak aortic blood flow acceleration, heart rate, and blood pressure was measured by the intraclass correlation coefficient (ICC) at each stage. ICC reliability of greater than 0.75 is considered excellent, 0.4 to 0.75 fair to good, and less than 0.4 poor. The reliability of all Doppler-derived parameters, heart rate, and blood pressure improved with increasing stage of exercise. Peak modal velocity, peak acceleration, heart rate, and manually obtained systolic blood pressure had ICCs of 0.75 or greater by stage 3. The reliability of Doppler-derived aortic blood flow parameters was good or excellent at rest and advanced stages of exercise. Continuous-wave Doppler echocardiography is a reliable method for performing studies to assess the effects of interventions on cardiovascular function during exercise.

Adult↗
PubMed2002

Development of a new seizure severity questionnaire: initial reliability and validity testing.

PURPOSE: This report describes the initial steps for development of a new scale to assess seizure severity as a treatment response. METHODS: Standard methodology was used to develop the test instrument. Item generation was performed by selecting items from other questionnaires, and asking patients and epileptologists about seizure components. Face and content validity were assessed in a pilot study with patients and observers. The questionnaire was formatted as a structured interview for a reliability study. Construct validity was assessed with three existing questionnaires. Inter-rater reliability and test-retest reliability were performed as two independent ratings on one day, and one re-interview. RESULTS: Based on item generation and pilot testing (33 patients, 28 observers), the Seizure Severity Questionnaire (SSQ) was organized into warning, activity-movement, and recovery (cognitive, emotional, and physical aspects) stages of seizures. Questions reviewed duration, severity, bothersomeness and overall ratings, and the most bothersome aspect of seizures. The mean SSQ Summary Score was 5.78+/-3.24, inter-rater reliability was 0.76 (N=91), and test-retest reliability was 0.74 (N=63). Construct validity showed statistically significant correlations with other scales. CONCLUSION: This study has explored the psychometric properties of the SSQ for face and content validity, inter-rater and test-retest reliability, and construct validity. The Summary Score reliably represents the major components of seizures.

Adult↗
PubMedDate not supplied

An analysis of the reliability phenomenon in the FitzHugh-Nagumo model.

The reliability of single neurons on realistic stimuli has been experimentally confirmed in a wide variety of animal preparations. We present a theoretical study of the reliability phenomenon in the FitzHugh-Nagumo model on white Gaussian stimulation. The analysis of the model's dynamics is performed in three regimes-the excitable, bistable, and oscillatory ones. We use tools from the random dynamical systems theory, such as the pullbacks and the estimation of the Lyapunov exponents and rotation number. The results show that for most stimulus intensities, trajectories converge to a single stochastic equilibrium point, and the leading Lyapunov exponent is negative. Consequently, in these regimes the discharge times are reliable in the sense that repeated presentation of the same aperiodic input segment evokes similar firing times after some transient time. Surprisingly, for a certain range of stimulus intensities, unreliable firing is observed due to the onset of stochastic chaos, as indicated by the estimated positive leading Lyapunov exponents. For this range of stimulus intensities, stochastic chaos occurs in the bistable regime and also expands in adjacent parts of the excitable and oscillating regimes. The obtained results are valuable in the explanation of experimental observations concerning the reliability of neurons stimulated with broad-band Gaussian inputs. They reveal two distinct neuronal response types. In the regime where the first Lyapunov has negative values, such inputs eventually lead neurons to reliable firing, and this suggests that any observed variance of firing times in reliability experiments is mainly due to internal noise. In the regime with positive Lyapunov exponents, the source of unreliable firing is stochastic chaos, a novel phenomenon in the reliability literature, whose origin and function need further investigation.

Computer Simulation↗
PubMed2004

Test-retest reliability of the Isernhagen Work Systems Functional Capacity Evaluation in healthy adults.

Aim of this study was to investigate test-retest reliability of the Isernhagen Work System Functional Capacity Evaluation (IWS FCE) in healthy subjects. The IWS FCE consists of 28 tests that reflect work-related activities such as lifting, carrying, bending, etc. A convenience sample of 26 healthy subjects participated in the study. The subjects' mean age was 34.9 years. Two FCE sessions were held within a 2-3 week interval. Descriptives per session, Intra Class Correlations (ICC), limits of agreement, Cohen's Kappa, and percentage of agreement were calculated where appropriate. An ICC of > or =0.75, a Kappa value > or =0.60, and a percentage of absolute agreement of > or =80% were considered acceptable reliability. Acceptable reliability was demonstrated for seven out of nine tests (78%) of the material handling group and the shuttle walk test based on ICC analyses only. Sixteen out of 17 criterion and ceiling tests (94%) showed acceptable reliability based on Kappa values and percentage of agreement. Of these 17 tests, 8 were eligible for further analysis, and of those 8 tests the reliability of one test was acceptable based on ICC analyses (13%). In conclusion, the test-retest reliability of the material-handling group is acceptable. Crude analyses of the ceiling and criterion tests reveal acceptable test-retest reliability of most, but not all, tests.

Adult↗
PubMed2003

The reliability of assessment of vibration sense.

OBJECTIVES: To assess the reliability of quantitative assessment of vibration sense with a Vibrameter type III. MATERIAL AND METHODS: We examined 111 healthy subjects (21-69 years). For intraobserver reliability, short-term (15 min between measurements) (n=11) and 24-h (n=28) reliability was tested. For interobserver reliability, a second tester performed the second measurement 15 min after the initial test (n=39). We also assessed the independent impact of effects of age, gender and height on vibration thresholds. RESULTS: In our study the intraobserver reliability is good [intraclass correlation coefficients (ICC) ranging from 0.55 to 0.99], whereas the interobserver reliability is moderate (ICC ranging from 0.32 to 0.88). Multiple linear regression analysis showed that age and--to a lesser extent--height was independently associated with the threshold values of the feet, but not with the thresholds of the hands. CONCLUSION: The use of a Vibrameter for measuring vibration thresholds in clinical practice and in multicentre studies is restricted because of the moderate interobserver reliability.

Adult↗