Test-retest Performance Research Articles

Test-retest reliability of a 16.1 km time trial in trained cyclists using the CompuTrainer ergometer

Laboratory based cycling time trials (TT) are widely used by both researchers and practitioners, as a method of assessing cycling performance in a controlled environment. Assessments of performance often use TT durations or distances between 20 min and one hour and in the UK the 10 mile (16.1 km) TT is the most frequently used race distance for trained cyclists. The 16.1 km TT has received relatively minimal, but increased attention as a performance criterion in the literature. Therefore, the aim of this study was to assess the reliability of 16.1 km TT performance in a large cohort of trained cyclists using the CompuTrainer cycling ergometer. Trained male cyclists (n = 58, mean±SD age 35±7 yr, height 179±6 cm, weight 79.1±9.4 kg, VO2max. 56.6±6.6 ml.kg.min-1, PPO 365±37 W) performed an initial incremental exercise test to determine PPO and VO2max. The participants then performed two 16.1 km TT on a CompuTrainer cycle ergometer separated by 3-7 days. Differences in time, power output and speed were determined using a Wilcoxon signed ranks or paired t-tests. Reproducibility of the TT performance measures was performed using the coefficient of variation (CV), intraclass correlations, and typical error (TE). There were no differences between any of the performance criteria for the whole cohort (Mean difference = 0.06 min, 0.09 km.h-1, 1.5 W, for time, mean speed and power respectively) between TT1 and TT2. All TT performance data were very reproducible (CV range = 1.1-2.7%) and demonstrated trivial or small TE. The slower cyclists demonstrated marginally lower reliability (CV range = 1.3-3.2%) compared to the fastest group (CV range = 0.7-2.0%). The 16.1 km TT on the CompuTrainer represents a very reliable performance criterion for trained cyclists. Interpretation of test-retest performance outcomes should be performed in the context of the TE of each performance indicator.

Parametric Methods for Dynamic 11C-Phenytoin PET Studies.

In this study, the performance of various methods for generating quantitative parametric images of dynamic 11C-phenytoin PET studies was evaluated. Methods: Double-baseline 60-min dynamic 11C-phenytoin PET studies, including online arterial sampling, were acquired for 6 healthy subjects. Parametric images were generated using Logan plot analysis, a basis function method, and spectral analysis. Parametric distribution volume (VT) and influx rate (K1) were compared with those obtained from nonlinear regression analysis of time-activity curves. In addition, global and regional test-retest (TRT) variability was determined for parametric K1 and VT values. Results: Biases in VT observed with all parametric methods were less than 5%. For K1, spectral analysis showed a negative bias of 16%. The mean TRT variabilities of VT and K1 were less than 10% for all methods. Shortening the scan duration to 45 min provided similar VT and K1 with comparable TRT performance compared with 60-min data. Conclusion: Among the various parametric methods tested, the basis function method provided parametric VT and K1 values with the least bias compared with nonlinear regression data and showed TRT variabilities lower than 5%, also for smaller volume-of-interest sizes (i.e., higher noise levels) and shorter scan duration.

Metabolically active tumour volume segmentation from dynamic [(18)F]FLT PET studies in non-small cell lung cancer.

BackgroundPositron emission tomography (PET) with 18F-3′-deoxy-3′-fluorothymidine ([18F]FLT) can be used to assess tumour proliferation. A kinetic-filtering (KF) classification algorithm has been suggested for segmentation of tumours in dynamic [18F]FLT PET data. The aim of the present study was to evaluate KF segmentation and its test-retest performance in [18F]FLT PET in non-small cell lung cancer (NSCLC) patients.MethodsNine NSCLC patients underwent two 60-min dynamic [18F]FLT PET scans within 7 days prior to treatment. Dynamic scans were reconstructed with filtered back projection (FBP) as well as with ordered subsets expectation maximisation (OSEM). Twenty-eight lesions were identified by an experienced physician. Segmentation was performed using KF applied to the dynamic data set and a source-to-background corrected 50% threshold (A50%) was applied to the sum image of the last three frames (45- to 60-min p.i.). Furthermore, several adaptations of KF were tested. Both for KF and A50% test-retest (TRT) variability of metabolically active tumour volume and standard uptake value (SUV) were evaluated.ResultsKF performed better on OSEM- than on FBP-reconstructed PET images. The original KF implementation segmented 15 out of 28 lesions, whereas A50% segmented each lesion. Adapted KF versions, however, were able to segment 26 out of 28 lesions. In the best performing adapted versions, metabolically active tumour volume and SUV TRT variability was similar to those of A50%. KF misclassified certain tumour areas as vertebrae or liver tissue, which was shown to be related to heterogeneous [18F]FLT uptake areas within the tumour.ConclusionsFor [18F]FLT PET studies in NSCLC patients, KF and A50% show comparable tumour volume segmentation performance. The KF method needs, however, a site-specific optimisation. The A50% is therefore a good alternative for tumour segmentation in NSCLC [18F]FLT PET studies in multicentre studies. Yet, it was observed that KF has the potential to subsegment lesions in high and low proliferative areas.

Model-free quantification of dynamic PET data using nonparametric deconvolution.

Dynamic positron emission tomography (PET) data are usually quantified using compartment models (CMs) or derived graphical approaches. Often, however, CMs either do not properly describe the tracer kinetics, or are not identifiable, leading to nonphysiologic estimates of the tracer binding. The PET data are modeled as the convolution of the metabolite-corrected input function and the tracer impulse response function (IRF) in the tissue. Using nonparametric deconvolution methods, it is possible to obtain model-free estimates of the IRF, from which functionals related to tracer volume of distribution and binding may be computed, but this approach has rarely been applied in PET. Here, we apply nonparametric deconvolution using singular value decomposition to simulated and test-retest clinical PET data with four reversible tracers well characterized by CMs ([(11)C]CUMI-101, [(11)C]DASB, [(11)C]PE2I, and [(11)C]WAY-100635), and systematically compare reproducibility, reliability, and identifiability of various IRF-derived functionals with that of traditional CMs outcomes. Results show that nonparametric deconvolution, completely free of any model assumptions, allows for estimates of tracer volume of distribution and binding that are very close to the estimates obtained with CMs and, in some cases, show better test-retest performance than CMs outcomes.

Detection of lactate in the striatum without contamination of macromolecules by J-difference editing MRS at 7T.

Lactate levels are measurable by MRS and are related to neural activity. Therefore, it is of interest to accurately measure lactate levels in the basal ganglia networks. If sufficiently stable, lactate measurements may be used to investigate alterations in dopaminergic signalling in the striatum, facilitating the detection and diagnosis of metabolic deficits. The aim of this study is to provide a J-difference editing MRS technique for the selective editing of lactate only, thus allowing the detection of lactate without contamination of overlapping macromolecules. As a validation procedure, macromolecule nulling was combined with J-difference editing, and this was compared with J-difference editing with a new highly selective editing pulse. The use of a high-field (7T) MR scanner enables the application of editing pulses with very narrow bandwidth, which are selective for lactate. We show that, despite the sensitivity to B0 offsets, the use of a highly selective editing pulse is more efficient for the detection of lactate than the combination of a broad-band editing pulse with macromolecule nulling. Although the signal-to-noise ratio of uncontaminated lactate detection in healthy subjects is relatively low, this article describes the test-retest performance of lactate detection in the striatum when using highly selective J-difference editing MRS at 7 T. The coefficient of variation, σw and intraclass correlation coefficients for within- and between-subject differences of lactate were determined. Lactate levels in the left and right striatum were determined twice in 10 healthy volunteers. Despite the fact that the test-retest performance of lactate detection is moderate with a coefficient of variation of about 20% for lactate, these values can be used for the design of new studies comparing, for example, patient populations with healthy controls.

Test-retest reliability of white matter structural brain networks: a multiband diffusion MRI study.

The multiband EPI sequence has been developed for the human connectome project to accelerate MRI data acquisition. However, no study has yet investigated the test-retest (TRT) reliability of the graph metrics of white matter (WM) structural brain networks constructed from this new sequence. Here, we employed a multiband diffusion MRI (dMRI) dataset with repeated scanning sessions and constructed both low- and high-resolution WM networks by volume- and surface-based parcellation methods. The reproducibility of network metrics and its dependence on type of construction procedures was assessed by the intra-class correlation coefficient (ICC). We observed conserved topological architecture of WM structural networks constructed from the multiband dMRI data as previous findings from conventional dMRI. For the global network properties, the first order metrics were more reliable than second order metrics. Between two parcellation methods, networks with volume-based parcellation showed better reliability than surface-based parcellation, especially for the global metrics. Between different resolutions, the high-resolution network exhibited higher TRT performance than the low-resolution in terms of the global metrics with a large effect size, whereas the low-resolution performs better in terms of local (region and connection) properties with a relatively low effect size. Moreover, we identified that the association and primary cortices showed higher reproducibility than the paralimbic/limbic regions. The important hub regions and rich-club connections are more reliable than the non-hub regions and connections. Finally, we found WM networks from the multiband dMRI showed higher reproducibility compared with those from the conventional dMRI. Together, our results demonstrated the fair to good reliability of the WM structural brain networks from the multiband EPI sequence, suggesting its potential utility for exploring individual differences and for clinical applications.

C-56 * Neuropsychological Test-Retest Performance following Traumatic Brain Injury in a Military Population

Objective: The purpose of this study was to determine the frequency of change in neuropsychological performance across time in deployed military personnel who experienced traumatic brain injury (TBI). The hypothesis was that frequency of changes would decrease as a function of time since injury. Method: Test-retest data was used to calculate reliable change index scores from 114 individuals over 10 neuropsychological tests. This data, part of a database of over 1, 000 evaluations of soldiers, was collected by a private practice in association with Camp Lejeune. These soldiers were deployed to Iraq/Afghanistan and were referred for comprehensive outpatient evaluation. The second testing session was on average 14 months, with a range of 2 to 34 months, following initial testing and was necessary for medical board policy compliance. Results: Mean percentage of the sample with significant increases for neuropsychological measures for < 6, 6–18, 19–29, and 30+ months since injury respectfully include; 13%, 16%, 7%, and 10%; significant decreases respectfully include 15%, 16%, 8%, and 10%. These mean changes include: CVLT-II, COWAT, Grooved Pegboard, TMT, Stroop, and WAIS-IV. Four tests were excluded due to suboptimal sample size. WAIS-IV working memory and similarities subtests supported the hypothesis with frequencies of changes decreasing as a function of time. Conclusion(s): The hypothesis was confirmed in subtests of the WAIS-IV, where changes decrease as a function of time since injury. Overall patterns seen in each group indicated highly variable neuropsychological performance following TBI up to 6 years following injury.

Detecting reliable cognitive change in individual patients with the MATRICS Consensus Cognitive Battery

ObjectiveClinicians often need to evaluate the treatment response of an individual person and to know that observed change is true improvement or worsening beyond usual week-to-week changes. This paper gives clinicians tools to evaluate individual changes on the MATRICS Consensus Cognitive Battery (MCCB). We compare three different approaches: a descriptive analysis of MCCB test–retest performance with no intervention, a reliable change index (RCI) approach controlling for average practice effects, and a regression approach. MethodData were gathered as part of the MATRICS PASS study (Nuechterlein et al., 2008). A total of 159 people with schizophrenia completed the MCCB at baseline and 4weeks later. Data were analyzed using an RCI and a regression formula establishing confidence intervals. ResultsThe RCI and regression approaches agree within one point when baseline values are close to the sample mean. However, the regression approach offers more accurate limits for expected change at the tails of the distribution of baseline scores. ConclusionsAlthough both approaches have their merits, the regression approach provides the most accurate measure of significant change across the full range of scores. As the RCI does not account for regression to the mean and has confidence limits that remain constant across baseline scores, the RCI approach effectively gives narrower confidence limits around an inaccurately predicted average change value. Further, despite the high test–retest reliability of the MCCB, a change in an individual's score must be relatively large to be confident that it is beyond normal month-to-month variation.

Performance Characteristics of the Verbal QuickDASH

To quantify the performance of the verbally administered Quick Disabilities of the Arm, Shoulder, and Hand (QuickDASH) questionnaire by assessing its replication of self-administered scores, its test-retest reliability, and its rate of scorable completion compared with its self-administered, written administration. Fifty patients presenting for initial visits to a hand clinic were enrolled regardless of diagnosis. All patients completed a written and a verbal QuickDASH 1 day apart (25 patients written first; 25 patients verbal first). Intraclass correlation coefficients quantified the verbal questionnaire's ability to reproduce written scores. Participants verbally completed the questionnaire a final time, 5 months later, to assess test-retest reliability. To quantify the usability of survey data, we compared percentages of scorable surveys between written and verbally administered QuickDASH questionnaires in this study and in prior studies within our division. The intraclass correlation coefficient between the 2 QuickDASH administration types for the entire sample was 0.91. Across all participants, there was a minimal change in mean score from a patient's written QuickDASH to that patient's first verbal QuickDASH score. Scoring consistency between QuickDASH administrations was similar for each administration sequence (phone followed by written vs. written followed by phone) and by diagnosis. Test-retest reliability between the 2 verbal administrations demonstrated good reliability and a minimal difference between scores. In this study, no written or verbal surveys were incomplete. Reviewing our practice, 17% of 258 written questionnaires produced unscorable data compared with 0% of 239 verbally administered surveys. Our results indicate that verbal administration of the QuickDASH replicates clinically relevant scores of the written QuickDASH, has good test-retest performance, andmay minimize unusable data. These data allow researchers greater flexibility in gatheringpatient outcome data in both retrospective and prospective studies. Diagnostic II.

Test–retest reliability of structural brain networks from diffusion MRI

Structural brain networks constructed from diffusion MRI (dMRI) and tractography have been demonstrated in healthy volunteers and more recently in various disorders affecting brain connectivity. However, few studies have addressed the reproducibility of the resulting networks. We measured the test–retest properties of such networks by varying several factors affecting network construction using ten healthy volunteers who underwent a dMRI protocol at 1.5T on two separate occasions.Each T1-weighted brain was parcellated into 84 regions-of-interest and network connections were identified using dMRI and two alternative tractography algorithms, two alternative seeding strategies, a white matter waypoint constraint and three alternative network weightings. In each case, four common graph-theoretic measures were obtained. Network properties were assessed both node-wise and per network in terms of the intraclass correlation coefficient (ICC) and by comparing within- and between-subject differences.Our findings suggest that test–retest performance was improved when: 1) seeding from white matter, rather than grey; and 2) using probabilistic tractography with a two-fibre model and sufficient streamlines, rather than deterministic tensor tractography. In terms of network weighting, a measure of streamline density produced better test–retest performance than tract-averaged diffusion anisotropy, although it remains unclear which is a more accurate representation of the underlying connectivity. For the best performing configuration, the global within-subject differences were between 3.2% and 11.9% with ICCs between 0.62 and 0.76. The mean nodal within-subject differences were between 5.2% and 24.2% with mean ICCs between 0.46 and 0.62. For 83.3% (70/84) of nodes, the within-subject differences were smaller than between-subject differences. Overall, these findings suggest that whilst current techniques produce networks capable of characterising the genuine between-subject differences in connectivity, future work must be undertaken to improve network reliability.

Reliability of Static and Dynamic Quantitative Sensory Testing in Patients With Painful Chronic Pancreatitis

Quantitative sensory testing (QST) has proven to be an important instrument to characterize mechanisms underlying somatic and neuropathic pain disorders. However, its reliability has not previously been established in patients with visceral pain. We investigated the test-retest reliability of static and dynamic QST in patients with visceral pain due to chronic pancreatitis. Sixty-two patients (38 men, 53 [11] y) with painful chronic pancreatitis were included. Static QST comprised sensory thresholds for pressure and electrical stimulation performed in the ventral and dorsal T10 dermatomes (sharing spinal innervation with the pancreas, ie, pancreatic viscerotomes) and in 4 heterologous regions (control areas). Dynamic QST comprised conditioned pain modulation. Measurements were obtained from 2 subsequent test sessions separated by 1 week. The reliability of static QST was generally high, with the best test-retest performance seen for pressure pain thresholds (intraclass correlation coefficients [ICC], 0.74) and electrical sensation thresholds (ICC, 0.66). In contrast, the reliability of dynamic QST was poor (ICC, 0.01). For static QST measures, the reliability was higher for pain thresholds compared with suprapain thresholds (P < 0.01). No differences between assessments in the pancreatic viscerotomes compared with heterologous regions were seen (P = 0.6). Sensory thresholds in the pancreatic viscerotomes and control areas were reproducible over time. In contrast, dynamic QST measurements reflecting active central modulation of pain processing state (ie, conditioned pain modulation) were not stable over time and showed considerable variability. These factors should be taken into consideration in case QST is used to follow disease mechanisms, drug effects, or effects of pain intervention.

Pain measurement: Visual Analogue Scale (VAS) and Verbal Rating Scale (VRS) in clinical trials with OTC analgesics in headache

The aim was to assess the performance of the Visual Analogue Scale (VAS) in patients recruited in a clinical trial with over the counter analgesics in headache. The Thomapyrin Study showed the significant superiority of the fixed combination of acetylsalicylic acid + paracetamol + caffeine over the combination without caffeine, the single preparations, and placebo in the treatment of headache. Patients enrolled into the study were trained in the handling of the VAS by naming categories of a 6-point Verbal Rating Scale (VRS). These data were used to evaluate the level of order consistency between the VAS and VRS, to deduce cut-off points for rescaling the continuous VAS into a discrete ordinal scale using the receiver operating characteristic methodology, and to assess the test-retest performance. Approximately 75% of the patients recorded the pain intensity on the VAS in the same order as given on the VRS. However, in 12.6% of patients, the German terms 'leicht' (mild) and 'mäßig' (moderate) were mixed up regarding their order on the VAS. Substantial overlapping of the frequency distributions of the VAS assessment were found for the VRS categories mild and moderate pain as well as severe and very severe pain. Grouping of the VAS assessments into a discrete ordinal scale necessitated a non-equidistant rescaling based on the categories of the VRS. By means of analysis of the receiver operating characteristic curves, the following cut-off points were determined on a 100 mm VAS: no pain 0-2 mm, mild pain 2-17 mm, moderate pain 17-47 mm, severe pain 47-77 mm, very severe pain 77-96 mm, most severe pain imaginable 96-100 mm. Repeated assessment up to several months after the first assessment demonstrated a test-retest agreement on the VAS in 61.0-91.4% of the patients, depending on the VRS category. This study shows that the VRS categories cannot be presented in an equidistant manner on the VAS, and that contrary to previous assumptions, the pain intensity descriptors are less clear and can have different meanings in different languages. Therefore, both in the 3rd edition of the International Headache Classification (ICHD-III) and in the guidelines for clinical trials of patients with headache illnesses, rather than a 4-grade VRS, a 6-grade or higher level VRS or a VAS should be recommended, with correspondingly broadly defined anchor points.

Training and Validation of Standardized Patients for Unannounced Assessment of Physicians' Management of Depression

Standardized patients (SPs) have been developed to measure practitioner performance in actual practice settings, but results have not been fully validated for psychiatric disorders. This study describes the process of creating reliable and valid SPs for unannounced assessment of general-practitioners' management of depression disorders in Iran. Ten psychology and nursing students (potential SPs) took part in a five-session course involving training in dialogue and body language. Five scenarios, along with corresponding checklists representing common presentations of mood disorders in primary-care settings, were developed by an expert group. The SPs' role-play performance of their respective scenario was videotaped and scored independently by three psychiatrists according to an observational rating scale to assess validity. The role-play was repeated after 1 week with the same scenario and the same doctor, to assess test-retest reliability. The reliability of each checklist to be used by the SPs was assessed by testing interrater reliability between groups of SPs. The cutoff score for the SPs' portrayal validity was 90% or above for all SPs. Mean interrater reliability for the checklists was acceptable for the SPs watching the same videos and filling in the checklists, while the mean kappa for assessing concurrent validity in filling in the checklists was lower. The test-retest performance for assessing reliability resulted in a mean kappa of 0.72. All SPs except one, who was not recruited, performed acceptably well. The authors have demonstrated a thorough validation of the technique of using standardized patients in the portrayal of depressive disorders in primary-care settings in Iran, which creates confidence in employing this technique to evaluate doctors' performance, for example, after an educational intervention. Similar methods of validation can be used for SPs' portrayal of other psychiatric disorders.

Aerobic fitness testing in 6- to 9-year-old children: reliability and validity of a modified Yo–Yo IR1 test and the Andersen test

This study analysed the reliability and validity of two intermittent running tests (the Yo-Yo IR1 test and the Andersen test) as tools for estimating VO(2max) in children under the age of 10. Two groups, aged 6-7 years (grade 0, n = 18) and 8-9 years (grade 2, n = 16), carried out two repetitions of a modified Yo-Yo IR1 test (2 × 16 m) and the Andersen test, as well as an incremental treadmill test, to directly determine the VO(2max). No significant differences were observed in test-retest performance of the Yo-Yo IR1 test [693 ± 418 (±SD) and 670 ± 328 m, r (2) = 0.79, CV = 19%, p > 0.05, n = 32) and the Andersen test (988 ± 77 and 989 ± 87 m, r (2) = 0.86, CV = 3%, p > 0.05, n = 31). The Yo-Yo IR1 (r (2) = 0.47, n = 31, p < 0.002) and Andersen test performance (r (2) = 0.53, n = 32, p < 0.001) correlated with the VO(2max). Yo-Yo IR1 performance correlated with Andersen test performance (r (2) = 0.74, n = 32, p < 0.0001). In conclusion, the Yo-Yo IR1 and the Andersen tests are reproducible and can be used as an indicator of aerobic fitness for 6- to 9-year-old children.

Spectral analysis of the voice in Down Syndrome

The voice quality of individuals with Down Syndrome (DS) is generally described as husky, monotonous and raucous. On the other hand, the voice of DS children is characterized by breathiness, roughness, and nasality and is typically low pitched. However, research on phonation and intonation in these participants is limited. The present study was designed to provide data from the spectral analysis of the human voice in DS people. A cross-sectional, observational design was applied. Thirty DS adults and 48 DS children were enrolled after clinical evaluation. Thirty men, 30 women and 46 children constituted the control group. The participants had to repeat a set of Italian words twice. The Real Time Pitch software manufactured by KayPENTAX recorded the voice. The following spectral descriptors were obtained for each word: Mean Frequency and standard deviation, Energy, Duration, Jitter and Shimmer. Test–retest performance was also checked. The voice of DS adults was characterized by a significantly higher Mean Frequency, particularly in males ( p < 0.0001), by a smaller variation ( p = 0.0044 in males and p = 0.0046 in females) and by a significantly lower level of Energy ( p = 0.0037 in males and p = 0.0025 females). Furthermore, limited to male adults, a shorter Duration ( p = 0.0156) and a smaller value of Shimmer ( p = 0.0014) was observed. The difference between DS children and age-matched controls was limited, reaching significance only for the Coefficient of Variation (CV) ( p = 0.031). The difference in Mean Frequency between adults and children was more evident in the control males than in all other groups. The lack of marked difference between voice characteristics of children with and without DS is outlined by findings. Pearson's correlation coefficients on repeated productions ranged from 0.23 (Jitter) to 0.86 (Mean Frequency) in children, and from 0.07 (Shimmer) to 0.86 (Mean Frequency) in adults. In the control group, all the coefficients ranged between 0.85 and 0.98. As expected, women had a higher Mean Frequency than men, but the CV was around 0.1 for both. By contrast, children had a significantly higher Mean Frequency and a lower CV. In conclusion, spectral analysis of the human voice is recommended in each laboratory of speech and language rehabilitation to exploit the accuracy of voice descriptors.

Psychometric properties of the Roland-Morris Disability Questionnaire compared to the Oswestry Disability Index: a systematic review

Objectives: To compare the psychometric properties of the Roland-Morris Disability Questionnaire and the Oswestry Disability Index used to measure physical ability in people with low back pain.Methods: A literature search of computerised databases from 1980 through June 2009 was performed using search terms: clinical assessment tools, Roland-Morris, questionnaires, back, spine, back pain, Oswestry Disability Index, psychometrics, reliability, validity, specificity and sensitivity. Twenty-three articles were reviewed using an adult population over 18 years old with acute, sub-acute and chronic low back pain.Results: The Roland-Morris Disability Questionnaire and the Oswestry Disability Index demonstrate good reliability in test–retest performance clinically at initial evaluation and up to 6 weeks following interventions. Two studies described the construct validity of the two measures as highly correlated with each other. Overall, it appears that both questionnaires have similar responsiveness rates of 0·76–0·78 but two studies report a responsiveness rate of 0·94 for the Oswestry.Discussion/Conclusion: The Roland-Morris Disability Questionnaire is most sensitive for patients with mild to moderate disability while the Oswestry Disability Index is most effective for persistent severe disability. Clinically, both questionnaires should be considered depending on the patient's objective presentation of disability. The clinician needs to determine either 'mild to moderate' or 'severe persistent disability' after a thorough history and physical exam is completed so that the appropriate questionnaire can be administered. This helps support the clinician's assessment of function, determine a patient's level of disability and provide outcome information.

Reliable Change Indices and Regression-Based Measures for the Rey-Osterreith Complex Figure Test in Partial Epilepsy Patients

The Rey-Osterreith Complex Figure (ROCF) is commonly used in evaluations of patients undergoing epilepsy surgery. We assessed test–retest performance on ROCF in 30 partial epilepsy patients (mean interval = 33.7 months) to derive reliable change indices (RCIs) and regression-based measures for change. ROCF reproductions were rescored by three raters (IRR Copy: 0.963; Delayed Recall: 0.986). The derived adjusted RC (90% CI) cutoff values for the ROCF Copy were (≤–6.5, ≥8.4) and were (≤–6.8, ≥10.0) for the Delayed Recall. Results from regression-based analyses were negative, using age, education, seizure duration, and age of onset, whereas a baseline score was a significant predictor of a follow-up score. The results provide a means to evaluate long-term outcome in epilepsy patients using the ROCF.

Test-Retest Reliability of Wideband Reflectance Measures in Infants under Screening and Diagnostic Test Conditions

The main goal of this study was to examine the test-retest reliability of wideband reflectance (WBR) measures collected from infants in screening and diagnostic hearing test environments. In addition, the results of WBR testing for infants who passed and failed otoacoustic emission (OAE) screening were examined to determine whether these measures distinguished between the two groups. Repeated WBR measures were collected from two groups of infants, one group tested in an outpatient hearing screening setting and the other group in a diagnostic test setting. For a total of 127 infants and a control group of 10 adults, repeated WBR measurements were made with the probe left in place between the two tests (T1 and T2) and after reinsertion of the probe (T3) for a total of 3 measurements. Test-retest differences were calculated for each individual across one-third octave frequency bands, and the mean and 90th percentile were calculated by subject group and OAE results. WBR patterns were also compared between infants who passed versus failed OAE screening. Mean test-retest differences were smaller for the diagnostic group than for the screening group. Test-retest differences were largest for the reinsertion condition and for the frequencies below 500 Hz. While the low frequencies were variable, the test-retest differences were smallest in the mid-frequency range which is thought to be the frequency range most sensitive to middle ear dysfunction. Test-retest performance did not differ between infants who passed or failed OAE screening. However, infants who failed OAE screening had significantly higher WBR in the range from 630 to 2000 Hz than infants who passed OAE screening. Test-retest performance was poor for frequencies below 500 Hz, but in general test-retest differences were small across the important mid-frequency range. Reinsertion of the probe between repeated tests yielded larger and more variable test-retest differences. Careful monitoring of probe fit and testing while infants are in a quiet state appears to be critical for obtaining reliable WBR results. Analysis of WBR results indicated significantly higher reflected energy in the mid-frequency range for infants who failed OAE screening than for those who passed OAE screening. Although conclusions are limited by the fact that the true status of the middle ear and cochlea were not known for the infants in this study, this result may indicate that a number of these infants failed OAE screening due to transient or permanent middle ear dysfunction which was detected by WBR.

The Water-Polo Intermittent Shuttle Test: A Match-Fitness Test for Water-Polo Players

To develop and validate an intermittent match-fitness test for water-polo players. Eight male junior players performed the Water Polo Intermittent Shuttle Test (WIST) twice to assess test reliability. To assess test sensitivity and validity, 104 male and female players from different competition standards and playing positions were tested. Eighteen players performed the WIST 5 times throughout a season to track fitness changes. Twelve players performed the WIST 48 hours before 4 consecutive National League games, and coaches awarded individual match-fitness scores based on game performances to assess the relationship between match fitness and test results. Heart rate (HR) and blood lactate (La(blood)) were measured during and after each test, respectively. Test-retest performance values were 216 +/- 90 vs 229 +/- 96 m (r = .98, P = .0001, coefficient of variation [CV] = 5.4%), peak HR 190 +/- 8 vs 192 +/- 10 bpm (r = .96, P = .0002, CV = 1.2%), and La(blood) 7.0 +/- 1.8 vs 6.4 +/- 1.6 mmol/L (r = .84, P = .0092, CV = 8.8%). Significant differences were observed among different standards of play (range junior regional females 102 +/- 10 m, senior international males 401 +/- 30 m) and playing positions (field players 305 +/- 154 m, center forwards 255 +/- 118, goal keepers 203 +/- 135 m). Test performance was lower in the early season (344 +/- 118 m) than the remainder of the season (range 459 +/- 138 to 550 +/- 176 m). WIST performance and match-fitness scores correlated for all field players (r = .57, P = .054) but more highly for field players other than center forwards (r = .83, P = .0027). The WIST is a reliable, sensitive, and valid match-fitness test for water-polo players. It could become a useful tool to assess the effects of different interventions on match fitness.

Observer-based rather than population-based confidence limits for determining probability of change in visual fields

Determining confidence intervals on psychophysical thresholds is straight forward if the psychometric function is known. In clinical settings, however, there is only partial information about the psychometric function, hence confidence limits are usually derived from test–retest data collected from many subjects. In this paper, we introduce a computational technique for deriving confidence limits for an individual’s endpoint threshold using data typically obtained in a clinical setting, rather than a database of test–retest performance. The technique uses probabilistic analysis of all possible response sequences in a test procedure. We then extend this procedure to allow for levels of typical uncertainty in data measurement.