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At least 1,333 records · Page 74Linked to original sources

PubMed2005

Reproducibility and clinical evaluation of rebound tonometry.

PURPOSE: To establish the reproducibility of a rebound tonometer in humans and the effect of corneal thickness on measurements, comparing it with Goldmann applanation tonometer. METHODS: In a first study designed to examine the reliability of the RBT, three experienced ophthalmologists undertook three consecutive intraocular pressure (IOP) measurements in 12 eyes of 12 normal subjects. A cross-sectional study was then performed to compare measurements obtained using the two tonometers in 147 eyes of 85 patients with ocular hypertension or glaucoma. RESULTS: Intraobserver coefficients of correlation obtained in the reproducibility study were 0.82, 0.73, and 0.87. Interobserver correlation was 0.82. There was a good correlation between IOP readings obtained by the RBT and the GAT (r = 0.865, P < 0.0001). RBT readings were consistently higher than GAT measurements (median difference, 1.8 +/- 2.8 mm Hg). A Bland-Altman plot indicated the 95% limits of agreement between the two methods were -3.7 to 7.3 mm Hg (slope = -0.022, P = 0.618). Using RBT, the point that best discriminated between patients with an IOP < or = 21 mm Hg and those with >21 mm Hg, as determined by the GAT was >23 mm Hg (sensitivity, 70.5%; specificity, 95.1%). In terms of pachymetry, the two tonometers behaved in a similar way, with correlation observed between IOP measurements and central corneal thickness. CONCLUSIONS: Rebound tonometry is a reproducible method of determining IOP in humans. In general, it tends to overestimate IOP compared with Goldmann applanation tonometry. The tonometers used in both methods are similarly affected by pachymetry.

Anthropometry↗

PubMed1997

Gender differences in cerebellar metabolism: test-retest reproducibility.

OBJECTIVE: The purpose of this study was to evaluate gender differences in baseline measures of regional brain metabolism and to assess their reproducibility. METHOD: Fifteen male and 13 female healthy subjects, whose mean age was 44 years, were tested with positron emission tomography and [18F]fluorodeoxyglucose (FDG) under resting conditions; eight of the men and 11 of the women underwent a second FDG scan under the same conditions 4-6 weeks later to assess the reproducibility of the previous results. RESULTS: There were no differences in whole brain metabolism between the women and the men. In the first evaluation the female subjects showed significantly higher metabolism in the temporal poles and cerebellum than the male subjects. During the second evaluation the female subjects had significantly higher metabolism only in the cerebellum. CONCLUSIONS: This study documents significant and reproducible gender differences in cerebellar metabolism; their functional significance merits further evaluation.

Adult↗

PubMed1996

TcPo2 measurement reproducibility during stress in stage II obliterative arterial disease.

Distal transcutaneous oxygen pressure measurement (TcPo2) is a noninvasive method of evaluating tissular hypoxemia in peripheral arterial disease. The poststress area of hypoxemia is a usefull technique for globally quantifying different parameters represented by TcPo2 curves during exercise. Although its use is increasingly widespread, the reproducibility of this method is poorly documented. TcPo2 was monitored three times at twenty-four hour intervals in 5 patients with stage II obliterative arterial disease during a treadmill walking test. In order to get uniform measurement conditions, each patient remained lying and then stood until TcPo2 became stable. The stress duration was calculated so that the pain step could not be reached. TcPo2 curves were digitized and a specific image analyzer was used to make replicate measurements. The area under the curve was computed, the horizontal axis determining the mean TcPo2 value at rest, the vertical axis representing the end of the exercise period. The corresponding areas under the curves ranged from 34 to 2212 mm2 (573.60; SD 826). Significant correlation coefficients were obtained among replicate measurements (first-second day, first-third day). However, owing to the wide range of area values, the authors decided to compute and use the coefficient of variation (STD/mean), since it was more representative of reproducibility. The mean of its value for 5 patients was 21%. Observation of the examination conditions resulted in several findings, especially the ability of certain patients to adapt their efforts to the exercise. These results indicate that TcPo2 poststress area measurements are reproducible, but the conditions of the exercise have to be rigorously defined and may still be improved.

Aged↗

PubMed1991

Reproducibility and sensitivity of oral malodor measurements with a portable sulphide monitor.

Forty-one subjects with bad breath were assessed for oral malodor and periodontal status on three occasions, at intervals of approximately one week. Oral malodor was assessed by measurement of peak and steady-state volatile sulphide levels with a portable sulphide monitor and by organoleptic measurement of whole-mouth, tongue dorsum, and interproximal dental odors by two independent judges. Reproducibility of measurements, assessed by paired t tests and Kappa testing, demonstrated no significant differences between any of the test results from the first and second appointments. Steady-state sulphide levels were the most reproducible of all tests. The ability of the tests to detect an expected reduction of malodor following a 0.2% chlorhexidine mouthrinse regimen was investigated by comparison of test values between the second and third appointments. Following the mouthrinsing treatment, 43% reductions of peak, 47% reductions of steady-state volatile sulphide levels, and 15-58% reductions in all other measurement categories were observed. The majority of the participants (22/41) had no pockets greater than 5 mm and exhibited both moderate gingival inflammation (Mean Gingival Index = 1.17) and moderate plaque accumulation (Mean Plaque Index = 1.84). Plaque Index and presence of pockets greater than 7 mm were weakly related to sulphide measurements. Whereas assessment of steady-state sulphide levels by the sulphide monitor does not constitute a direct measure of oral malodor, its relation to organoleptic measurement, superior reproducibility, objectivity, and sensitivity support the use of the sulphide monitor in clinical studies.

Breath Tests↗

PubMed1997

Nutrition risk classification: a reproducible and valid tool for nurses.

BACKGROUND: Incorporating the nursing staff to assist with the screening process on admission will allow patients who are at nutritional risk to be assessed by registered dietitians earlier in their hospital stay. The goal of this study was to develop an objective, valid, reproducible nutrition screen for use by registered nurses (RNs) to allow for nutrition classifications of hospitalized patients. METHODS: The current nursing admission assessment form was modified to contain questions on weight loss history, percentage of ideal body weight, and alterations in dietary intake and gastrointestinal function. Assessments were completed within 48 hours of admission. On the basis of the answers to these questions, patients were classified as "at nutritional risk" or "low nutritional risk." In phase 1, to assess reproducibility of the form, a prospective study between staff RNs and a nutritionist was undertaken on 186 consecutive adult admissions. Nutrition screening and classification was done independently by both practitioners. In phase 2 of the study, prospective validation of the form contrasting prealbumin (PAB) levels with RN nutritional risk classification (n = 56) was investigated. RESULTS: Interobserver agreement of nutrition classification between RN and nutritionist was 97.3% (p = .95). Twenty-nine patients were classified at low nutritional risk (27 normal PAB and 2 low PAB); 27 patients were classified as at nutritional risk (16 normal PAB and 11 low PAB) (chi 2 = 8.9, p < .003, power 0.8). The sensitivity of the tool was 84.6%. CONCLUSION: To our knowledge, this is the first nutrition screening tool designed for staff RNs that has been tested for both validity and reproducibility.

Adult↗

PubMed2006

The reproducibility and validity of the Canadian Occupational Performance Measure in parents of children with disabilities.

OBJECTIVE: To study the reproducibility (inter-rater agreement), the construct and criterion validity of the Canadian Occupational Performance Measure (COPM) in the parents of children with disabilities. DESIGN: The COPM was administered twice by two different occupational therapists. The inter-rater agreement of the content of the prioritized problems was explored. Data analysis of the reproducibility of the scores was based on the Bland and Altman method. Measures used: The construct validity was studied by comparing the results of the COPM with the Pediatric Evaluation of Disability Inventory, and a quality of life questionnaire. The criterion validity was verified with an open-ended question. SETTING: Occupational therapy departments of a university hospital and three rehabilitation institutes. SUBJECTS: One hundred and twenty-nine consecutive parents of children referred for occupational therapy. RESULTS: Data were obtained for 80 children with a mean age of 3.7 years (range 1-7.5). Of the prioritized problems identified in the first interview, 80% were also prioritized in the second interview. The limits of agreement were - 2.4 to +2.3 for the mean performance score and - 2.3 to + 2.6 for the mean satisfaction score. Assumptions about the construct and criterion validity were confirmed. CONCLUSIONS: The inter-rater agreement of the prioritized problems is good enough for client-centred occupational therapy. The reproducibility of the performance and satisfaction scores is moderate. The results support the construct and criterion validity. The COPM identifies many child-unique problems that are not assessed with existing standardized measurement instruments or with a simple open-ended question.

Activities of Daily Living↗

PubMedDate not supplied

Reproducibility of predictor variables from a validated clinical rule.

It has been suggested that clinical prediction rules are not reproducible, and that the most important variables frequently do not appear in replicate models. The authors studied the reproducibility of a validated rule for predicting radiographic evidence of pneumonia (ROC areas for the training and validation cohorts, 0.816 and 0.821, respectively). Two hundred replicate samples of size 250 and size 500 were generated by sampling without replacement from the original training cohort of 905 patients with a 14.6% prevalence of pneumonia. Forward selection was performed among 31 candidate variables by stepwise logistic regression. Using as reproducibility criteria: 1) inclusion of all five variables from the original model in the original order; 2) inclusion of all five variables in any order; 3) inclusion of the first three variables; 4) inclusion of the first two variables; 5) inclusion of the first variable; and 6) inclusion of any of the five variables: 2.5%, 13.5%, 48.5%, 85.5%, 98.0%, and 100% of replicate models of sample size 500, respectively, met the criteria, whereas 0%, 0%, 16.5%, 49.0%, 71.5%, and 97.5% of models of sample size 250 met the criteria (all comparisons by sample size p < .0001 except for criteria 1 and 6, p = 0.07). Mean ROC areas in the training and validation samples were 0.829 and 0.791 for replicate models of sample size 500, and 0.831 and 0.779 for models of sample size 250. There was no significant difference in ROC areas between training and validation cohorts for 80.5% of models of sample size 500, and for 75.3% of models of sample size 250.(ABSTRACT TRUNCATED AT 250 WORDS)

Ambulatory Care↗

PubMedDate not supplied

Reproducibility of Genucom knee analysis system testing.

The Genucom knee analysis system was studied to determine the reproducibility of test results. In the first phase of the study we investigated the reproducibility of anterior/posterior stress tests at 30 degrees and 90 degrees of flexion and varus/valgus stress tests at 20 degrees of flexion in 10 control subjects during three seatings on 3 separate days. In the second phase we studied the effect of errors in the digitization procedure (a part of the patient installation process) on anterior/posterior translation measurements. In the third phase we studied the reproducibility of a battery of tests in patients with chronic unilateral ACL deficient knees. The test battery was repeated 8 times on each knee on 6 separate days. In Phase I, analysis of variance revealed no significant differences between tests within a single seating. The day-to-day variance of all subjects was not significant, but we found a significant interaction between day and subject which was due to significant day-to-day differences in individual subjects. We found in Phase II that changing the location of the tibial joint line digitization points in the anterior/posterior or proximal/distal direction affected anterior/posterior translation measurements. Effects were larger at 30 degrees of flexion than at 90 degrees and when both the medial and lateral points were moved. Movement of the femoral condylar points resulted in a similar pattern of effects. In Phase III, although we found significant differences between our two examiners, there were no significant intraexaminer test-to-test (within seating) effects. Additionally, while there was no significant day-to-day variance overall, we found a significant interaction between day and subject.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed2006

Impedance cardiography derived cardiac output in hemodialysis patients: a study of reproducibility and comparison with echocardiography.

BACKGROUND: Hemodialysis patients experience a variety of hemodynamic abnormalities that contribute to cardiovascular disease mortality which is the leading cause of death in these patients. Impedance cardiography has been utilized in order to monitor cardiac hemodynamics with lower cost and inconvenience, but it has not been appropriately validated in the hemodialysis population. AIM: We repeatedly used impedance cardiography to assess short- (48 hours) and long-term (15 days) reproducibility of cardiac output measurements and we compared baseline impedance cardiography measurements with echocardiographic measurements. PATIENTS AND METHODS: We studied 109 stable hemodialysis patients, aged 59.70 +/- 11.97 years being on hemodialysis for 67.59 +/- 40.15 months, on a non-dialysis day. Cardiac output was obtained with the BioZ impedance cardiography system (Cardiodynamics, San Diego, Ca, USA). Baseline echocardiography was performed using a Hewlett-Packard Sonos 2500 (Andover, Mass., USA). RESULTS: The values of impedance cardiography derived cardiac output were 5.28 +/- 0.79, 5.27 +/- 0.75 and 5.25 +/- 0.74 l/min at baseline (107 patients), 48 hours (107 patients) and 15 days (98 patients) respectively, showing high reproducibility. Bland and Altman analysis estimated that bias at 48 hours and at 15 days were: -0.013 (95% confidence intervals = -0.045 to 0.019) and 0.028, (95% confidence intervals = -0.044 to 0.101), respectively. In addition baseline impedance cardiography derived cardiac output was significantly correlated with the echocardiographic derived cardiac output (r = 0.9, p < 0.0001). CONCLUSION: Impedance cardiography is a simple non invasive technique for cardiac output estimation in hemodialysis patients which has high reproducibility when performed under controlled conditions, and is closely correlated with echocardiographic measurements of cardiac output.

Aged↗

PubMed2002

The acquired midtarsus deformity classification system--interobserver reliability and intraobserver reproducibility.

A radiographic classification (Schon's) divides Charcot midtarsus deformities into four types identified by Roman numerals (I to IV), according to the anatomical location of the pathological process,11 and an objective method of severity staging using radiographic criteria is introduced and tested. A beta stage is assigned if one of the following criteria is met: 1. a dislocation is present; 2. the lateral talar-first metatarsal angle is > or = 30 degrees; 3. the lateral calcaneal-fifth metatarsal angle > or = 0; or 4. the AP talar-first metatarsal angle is > or = 35 degrees. An alpha stage can be assigned when all four features are absent. Clinical features useful in assessing and managing these deformities have been associated with the various types and stages. To determine whether the classification system is valid, a study was performed. Two examination booklets and an instructional booklet designed to teach the method were distributed to 75 orthopaedic surgeons at the AOFAS summer meeting to test for intraobserver reproducibility and interobserver reliability. Information about the participants was recorded, and the tests were scored. The highest scores for correct responses were achieved by foot and ankle fellows, followed by orthopaedic residents. Attending orthopaedic surgeons achieved the lowest scores. The most common error was a type I deformity misidentified as a type II. The interobserver reliability for correctly classifying the deformities was 81%, and the intraobserver reproducibility was 97%. We concluded that this classification system, intended to clarify the patterns of acquired midfoot collapse, permits assignment of both anatomic type (I to IV) and degree of severity (alpha-beta) with high reliability and reproducibility. It can therefore be used as a tool for diagnosis, planning treatment, and assessing the prognosis.

Charcot-Marie-Tooth Disease↗

PubMedDate not supplied

Reproducibility of optic nerve head measurements obtained by optical coherence tomography.

PURPOSE: To evaluate reproducibility of optic nerve head (ONH) morphometry measurements obtained by optical coherence tomography (the fast optical disk protocol of the -Zeiss model 3000 OCT system) in normal and glaucomatous eyes. METHODS: Prospective instrument-evaluation study. ONH measurements for 20 eyes were obtained in eight scan sessions taken during two visits to an ophthalmology clinic (10 normal patients, 10 glaucoma patients, one eye per subject). At every one of the eight sessions for each eye, estimates of eight ONH morphometry variables (see Main outcome measures) were obtained. The first two sessions were performed by two operators, followed by a 30-minute break. The same operators then completed a third and fourth session. This sequence was duplicated on a second visit. Intrasession, intersession, intervisit, and interoperator reproducibility of the eight variables were calculated by the use of a components variance model. Intraclass correlation coefficients (ICC) were used to assess reliability. RESULTS: Vertical integrated rim area, horizontal integrated rim area, disk area, cup area, rim area, cup/disk area ratio, cup/disk horizontal ratio, cup/disk vertical ratio. With the exception of the horizontal integrated rim area and rim area in normal subjects, the factor subject was the most important source of variance for all variables. Reliability values as measured by ICC for normal eyes were above 81%, with the exception of measurements of the horizontal integrated rim area (23.1%), rim area (33.3%), and disk area (64.7%). For glaucomatous eyes all values were above 85%, with the exception of the disk area (68.1%). CONCLUSIONS: ONH measurements obtained using the fast optical disk protocol of the Zeiss 3000 OCT system show good reproducibility, for both normal and glaucomatous eyes.

Adult↗

PubMed2001

The reproducibility and sample size requirements of exercise-induced bronchoconstriction measurements.

Dry air exercise challenges are frequently used to screen medications that have potential utility in the management of exercise-induced bronchoconstriction (EIB). The purpose of this study was to determine the reproducibility of three outcome measurements made using such challenges, and sample size requirements for drug evaluation studies based on these outcomes. Forty adult subjects with asthma, who tested positively on a screening exercise challenge, were subjected to two further identical challenges, separated by 1 to >35 days. Outcome measurements included the maximum per cent fall in forced expiratory volume in one second (FEV1), after exercise (% fallmax), and the area under the per cent fall in FEV1/time curve for 30 min (AUC30) and 60 min (AUC60) after exercise. The reproducibility of these outcomes, as assessed by intraclass correlation coefficients was 0.72, 0.53 and 0.35 for % fallmax, AUC30 and AUC60 measurements, respectively. The sample size requirements to demonstrate an attenuation of EIB equivalent to a 50% reduction in % fallmax was 9, 14 and 19 subjects for the % fallmax, AUC30 and AUC60 responses, respectively (90% power). It is concluded that the maximum percentage fall in forced expiratory volume in one second has greater reproducibility and results in greater power in clinical trials than area under the curve measurements. Sample size calculation curves are provided which may be used in study design and interpretation of published studies.

Adult↗

PubMed2003

Lack of reproducibility of linkage results in serially measured blood pressure data.

BACKGROUND: Using the longitudinal Framingham Heart Study data on blood pressure, we analyzed the reproducibility of linkage measures from serial cross-sectional surveys of a defined population by performing genome-wide model-free linkage analyses to systolic blood pressure (SBP) and history of hypertension (HTN) measured at five separate time points. RESULTS: The heritability of SBP was relatively stable over time, ranging from 11.6 to 23.5% (coefficient of variation = 25.7%). However, the variability in linkage results was much greater. The average correlation in LOD scores at any pair of time points was 0.46 for HTN (NPL All LOD) and 0.17 for SBP (Variance Components LOD). No evidence of reproducible linkage results was found, with a mean kappa of 0.02 for linkage to HTN and -0.03 for SBP linkage. At loci with potential evidence for linkage (LOD > 1.0 at one or more time points), the correlation was even lower. The coefficient of variation at loci with potential evidence of linkage was 126% for HTN and 135% for SBP. None of 15 chromosomal regions for HTN and only one of 28 regions for SBP with potential evidence for linkage had a LOD > 1.0 at more than two of the five time points. CONCLUSION: These data suggest that, although heritability estimates at different time points are relatively robust, the reproducibility of linkage results in serial cross-sectional samples of a geographically defined population at successive time points is poor. This may explain in part the difficulty encountered in replicating linkage studies of complex phenotypes.

Adult↗

PubMed2006

Intra- and inter-radiation therapist reproducibility of daily isocenter verification using prostatic fiducial markers.

BACKGROUND: We sought to determine the intra- and inter-radiation therapist reproducibility of a previously established matching technique for daily verification and correction of isocenter position relative to intraprostatic fiducial markers (FM). MATERIALS AND METHODS: With the patient in the treatment position, anterior-posterior and left lateral electronic images are acquired on an amorphous silicon flat panel electronic portal imaging device. After each portal image is acquired, the therapist manually translates and aligns the fiducial markers in the image to the marker contours on the digitally reconstructed radiograph. The distances between the planned and actual isocenter location is displayed. In order to determine the reproducibility of this technique, four therapists repeated and recorded this operation two separate times on 20 previously acquired portal image datasets from two patients. The data were analyzed to obtain the mean variability in the distances measured between and within observers. RESULTS: The mean and median intra-observer variability ranged from 0.4 to 0.7 mm and 0.3 to 0.6 mm respectively with a standard deviation of 0.4 to 1.0 mm. Inter-observer results were similar with a mean variability of 0.9 mm, a median of 0.6 mm, and a standard deviation of 0.7 mm. When using a 5 mm threshold, only 0.5% of treatments will undergo a table shift due to intra or inter-observer error, increasing to an error rate of 2.4% if this threshold were reduced to 3 mm. CONCLUSION: We have found high reproducibility with a previously established method for daily verification and correction of isocenter position relative to prostatic fiducial markers using electronic portal imaging.

Equipment Design↗

PubMed1998

Reproducibility of the alternating breath test of fractional inspired O2 in infants.

We conducted a reproducibility study of the alternating breath test (ABT) for assessing peripheral chemoreceptor function in infants. The ABT delivers a rapid hypoxic stimulus to the peripheral chemoreceptors with breath-by-breath alternations of the inspired O2 fraction. The reproducibility of the ABT performed on a single occasion has not been extensively studied in infants. Eight unsedated infants (postnatal age, 22+/-19 d; weight, 3.2+/-0.4 kg) were studied in standardized conditions: morning naps, supine position, room temperature 22-24 degrees C, quiet sleep, and face mask attached to a pneumotachograph connected to a two-way electric valve. Respiratory gases were analyzed by mass spectrometer. Two ABTs were performed. Each included a 2-min control run (CR) alternating between air and air, and a 2-min test run (TR) alternating between air and 0.15 O2. After data preprocessing, on average 13+/-11% of the data were rejected because of sighs, apneas, and cycles with the fraction of inspired oxygen above 0.17. Using the remaining validated breaths, the response to ABT was calculated for the CR, for all breaths in the TR (TR(T)), and for the first 50 breaths of the TR (TR50). During the ABTs oxygen saturation did not fall below 96%, and heart rate was not affected. Inspired and end-tidal CO2 fractions remained unchanged during the ABTs. FetO2 oscillated in TRs at a lower values than in CRs and differed significantly between breaths of air and hypoxic breaths of TRs. All infants responded to ABT with percentage alternation coefficients of TRs significantly greater than those of CRs for all respiratory variables. The values of the coefficients were not significantly different between both ABT, and between TR50 and TR(T). The greatest values of the coefficients were for timing variables compared with flows and volume. We conclude that the ABT is a reproducible test of peripheral chemoreceptor function under standardized conditions.

Breath Tests↗

PubMed2005

Reproducibility of nighttime salivary cortisol and its use in the diagnosis of hypercortisolism compared with urinary free cortisol and overnight dexamethasone suppression test.

BACKGROUND/METHODS: Nighttime salivary cortisol (NSC) has been suggested to be a useful diagnostic test for Cushing's syndrome (CS). In the absence of published data on its day-to-day variability, we assessed the reproducibility of NSC by repeated measurements in healthy volunteers. Its diagnostic performance was compared with 24-h urinary free cortisol (UFC) and 1 mg overnight dexamethasone suppression test in 12 patients with CS, 20 healthy volunteers, 14 referred patients in which CS was excluded or not firmly established, 16 obese patients, and 20 women in late pregnancy. RESULTS: NSC showed a superior reproducibility in healthy volunteers with a low day-to-day variability as reflected by an intraclass correlation coefficient of 0.78. The receiver operating characteristic curve-estimated cutoff of 6.1 nmol/liter (0.22 microg/dl) demonstrated a sensitivity and specificity of 100% (area under the receiver operating characteristic curve, 1.0; 95% confidence interval, 0.94-1.0) in the diagnosis of CS. NSC, 24-h UFC [after adjusting the local laboratory cutoff to 504 nmol/d (183 microg/d)], and the urinary cortisol/creatinine ratio showed a tendency to be superior to 1 mg dexamethasone suppression test in correctly identifying CS. In late pregnancy, the preserved diurnal variation at a higher level of salivary cortisol reduced the specificity of NSC to 75%. CONCLUSION: Based on its remarkable reproducibility, easy noninvasive nature, and at least similar diagnostic performance, NSC appears to be a preferable alternative to 24-h UFC as a first-line screening test for CS. The cutoff values of NSC, 24-h UFC, and urinary cortisol/creatinine ratio have to be carefully adjusted using assay and center-specific reference ranges of sufficiently large populations.

Adult↗

PubMed1990

Reproducibility of growth hormone testing procedures: a comparison between 24-hour integrated concentration and pharmacological stimulation.

The purpose of this study was to compare the reproducibility of two approaches to the evaluation of GH secretion: the integrated concentration of GH (IC-GH), a physiological test of GH secretion, and pharmacological stimulation tests. IC-GH was determined in 40 poorly growing children twice within 4 weeks. The first and second IC-GH were highly correlated r = 0.859, P less than 0.001. One hundred and thirteen poorly growing children underwent pharmacological GH stimulation tests twice within 6 weeks. A moderate correlation was found between the first and second pharmacological test r = 0.524, P less than 0.01. Among the three pharmacological stimuli studied, clonidine (n = 81) had the highest reproducibility followed by arginine (n = 20), and insulin (n = 12). We conclude that IC-GH is more consistently reproducible than the GH response to repeated pharmacological stimulation.

Adolescent↗

PubMed2003

Intrasubject reproducibility of presurgical language lateralization and mapping using fMRI.

BACKGROUND: fMRI is becoming a standard tool for the presurgical lateralization and mapping of brain areas involved in language processing. However, its within-subject reproducibility has yet to be fully explored. OBJECTIVE: To evaluate within-test and test-retest reliability of language fMRI in consecutive patients undergoing evaluation for epilepsy surgery. METHODS: Thirty-four unselected patients were investigated once (within-test reliability) and 12 patients twice (test-retest reliability). The imaging series consisted of an alternating 25-second synonym judgment condition with a 25-second letter-matching condition repeated 15 times. Reproducibility of activation maps of the first and second half of session 1 or activation maps of sessions 1 and 2 was evaluated by comparing one global and three regional lateralization indexes (Broca's area, remaining prefrontal cortex, temporoparietal area) and on a voxel-by-voxel basis (intraclass correlation coefficient, percentage overlap, correlation of t-values). RESULTS: Global and regional language lateralization was achieved with high reliability within and across sessions. Reproducibility was evenly distributed across both hemispheres but not within each hemisphere. Frontal activations were more reliable than temporoparietal ones. Depending on the statistical threshold chosen, the voxel-by-voxel analysis revealed a mean overlap of activations derived from the first and second investigation of up to 48.9%. CONCLUSION: Language fMRI proved sufficiently reliable for the determination of global and regional lateralization of language representation in individual unselected patients with epilepsy.

Adolescent↗