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PubMed2003

Correlation between performance on the Continuous Performance Test and economic costs in patients with schizophrenia.

The aim of the present study was to determine whether a relationship existed between the performance on the Continuous Performance Test (CPT) and the economic costs of schizophrenic patients in Taiwan. Forty-six schizophrenic patients and their caregivers were enrolled. The CPT is a vigilance task requiring the monitoring of rapid information processing and the detection of briefly presented target stimuli. Each patients undertook two CPT sections: the unmasked task and the masked task. Economic Cost Questionnaires were used for assessing the direct and indirect costs of the illness. The patients' performance on the masked version of the CPT correlated significantly with the indirect costs, although there was no significant relationship between CPT scores and direct costs. Schizophrenic patients with more severely impaired sustained attention, particularly as measured by CPT, may incur higher indirect costs.

Adolescent↗

PubMed2003

The relationship between performance-based visual acuity screening, self-reported visual acuity, and neuropsychological performance.

Despite frequent cautions in the literature concerning the importance of visual acuity in neuropsychological testing, there are few published empirical investigations of what constitutes "sufficient" visual acuity, nor are there published guidelines for performance-based visual screening techniques. The current study attempted to validate the utility of a visual acuity screening technique by examining individuals with varying visual ability on neuropsychological measures. Results revealed declines on neuropsychological measures associated with reduced visual acuity, as well as discrepancies between self-reported and measured visual acuity, with neuropsychological performance being more closely related to a performance-based measure of visual acuity than to self-reported visual acuity. Clinical implications are discussed.

Adult↗

PubMed1997

Asymptomatic HIV-infected women: preliminary study of quantitative EEG activity and performance on a continuous performance test.

Several studies have examined the electrophysiological correlates of human immunodeficiency virus (HIV) infection in medically asymptomatic men. Although the rates of HIV infection are increasing at a greater rate in women than men, there have been no publications to date of electrophysiological functioning in HIV-infected women. In the present study, quantitative electroencephalographic (qEEG) activity was measured in 22 women (11 asymptomatic HIV-seropositive and 11 HIV-seronegative) utilizing a procedure comprised of three auditory continuous performance tests and a set of qEEG components derived from principal components analysis. No significant group differences were found in qEEG or in performance on the continuous performance tests; however, task-related differences were detected across groups between simple and complex language tasks in EEG fast beta power, delta power, and a left-hemisphere principal components analysis-derived EEG component. In examining the electrophysiological correlates of HIV infection, researchers might employ a similar methodology while increasing the sample size and varying the task modality or difficulty.

Adult↗

PubMed1999

A new visual performance test offers new variables for assessing daytime vigilance: short pauses in performance.

A new visual performance test, VigiMouse, was evaluated with the aid of 6 volunteering pediatry residents. The results were compared with a visual analogue scale in differentiating four different states: mild sleep deprivation, low blood alcohol level, a combination of both, and the normal state. A normal night shift at a busy pediatric ward was chosen to represent sleep deprivation. A new set of parameters based on short pauses in performance proved to be more sensitive in detecting small changes in performance than parameters based on reaction times.

Adult↗

PubMedDate not supplied

A developmental analysis of the relationship between hand preference and performance: II. A performance-based method of measuring hand preference in children.

The present study describes a performance-based method of measuring hand preference in children. Three aspects of handedness were considered to be important in developing the paradigm (a) overall hand preference across a number of tasks, (b) consistency of hand use and, (c) the use of the preferred hand in a bimanual task. The new paradigm, termed the WatHand Box Test (WBT), requires participants to perform a variety of unimanual tasks such as, using a hammer, tossing a ball, and opening a lock with a key. To determine the validity of the WBT and examine the developmental trends in hand preference, eighty right-handed children and adults (ages 3-4, 6-7, 9-10, and 18-24 years) performed the WBT. First, the WBT was found to correlate significantly with scores on a standard hand preference questionnaire for the adults. As well, significant developmental trends were noted in hand preference as measured by the WBT. Most specifically, three- and four-year-olds had significantly lower scores on the WBT indicating a less stable pattern of hand preference than in the other three age groups.

Adolescent↗

PubMed1987

Lesions in the septo-hippocampal system or prelimbic cortex of rats do not alter the performance of a T-maze visual discrimination task but disrupt the performance of a T-maze alternation task.

Rats with lesions in the posterodorsal septum (SEP), prelimbic cortex (PRE), and control operations (CON) were tested in a continuous alternation task (intertrial interval, ITI = 0 s) and a visual discrimination task (ITI ca 100 s) in a T-maze. CON rats performed the alternation task significantly better than rats with SEP or PRE lesions. PRE rats, but not SEP rats, were able to master the task with continued practice. The three groups did not differ in performance of the visual discrimination task. These data suggest that the septo-hippocampal system and, to a lesser extent, the prelimbic cortex are specifically involved in the memory processes necessary for the performance of an alternation but not a visual discrimination task in a T-maze.

Animals↗

PubMed1984

Effects of anxiety and depression on anagram performance, ratings of cognitive interference, and the negative subjective evaluation of performance.

Studied whether any differential effects of anxiety and depression could be discerned in the anagram performance, ratings of cognitive interference, and subjective evaluation of anagram performance displayed by college students. Seventy-two undergraduates (36 male, 36 female) were selected to participate in the present experiment on the basis of their scores on the State-Trait Anxiety Inventory (A-Trait) and/or the Beck Depression Inventory. Results showed that depressed-anxious and anxious Ss displayed a tendency toward reduced efficiency in anagram solution, rated themselves as having experienced significantly more cognitive interference during the anagram task, and displayed a significantly more negative subjective evaluation of their anagram performance than did control Ss. Quasi-F analyses revealed that these results were related significantly to the anxiety factor common to both depressed-anxious and anxious Ss. Implications of these results for future research on anxiety and depression were discussed.

Anxiety↗

PubMed2006

High-throughput quantification for a drug mixture in rat plasma-a comparison of Ultra Performance liquid chromatography/tandem mass spectrometry with high-performance liquid chromatography/tandem mass spectrometry.

A quantitative Ultra Performance liquid chromatography/tandem mass spectrometry (UPL/MS/MS) protocol was developed for a five-compound mixture in rat plasma. A similar high-performance liquid chromatography/tandem mass spectrometry (HPLC/MS/MS) quantification protocol was developed for comparison purposes. Among the five test compounds, three preferred positive electrospray ionization (ESI) and two preferred negative ESI. As a result, both UPLC/MS/MS and HPLC/MS/MS analyses were performed by having the mass spectrometer collecting ESI multiple reaction monitoring (MRM) data in both positive and negative ion modes during a single injection. Peak widths for most standards were 4.8 s for the HPLC analysis and 2.4 s for the UPLC analysis. There were 17 to 20 data points obtained for each of the LC peaks. Compared with the HPLC/MS/MS method, the UPLC/MS/MS method offered 3-fold decrease in retention time, up to 10-fold increase in detected peak height, with 2-fold decrease in peak width. Limits of quantification (LOQs) for both HPLC and UPLC methods were evaluated. For UPLC/MS/MS analysis, a linear range up to four orders of magnitude was obtained with r2 values ranging from 0.991 to 0.998. The LOQs for the five analytes ranged from 0.08 to 9.85 ng/mL. Three levels of quality control (QC) samples were analyzed. For the UPLC/MS/MS protocol, the percent relative standard deviation (RSD%) for low QC (2 ng/mL) ranged from 3.42 to 8.67% (N = 18). The carryover of the UPLC/MS/MS protocol was negligible and the robustness of the UPLC/MS/MS system was evaluated with up to 963 QC injections.

Animals↗

PubMed2005

Comparative study on the analytical performance of three waveforms for the determination of several aminoglycoside antibiotics with high performance liquid chromatography using amperometric detection.

A preliminary comparative study was carried out on the analytical performances of a new six-potential waveform and other two detection waveforms, triple-potential waveform and quadruple-potential waveform. The analytical performances compared included signal response, background noise, signal/noise ratio and signal stability. Compared with triple-potential waveform and quadruple-potential waveform, the new six-potential waveform had higher signal response, signal/noise ratio, and sensitivity. As for determination reproducibility, the six-potential waveform also exhibited a slightly better performance than the other two waveforms. Under the selected experimental conditions based on the six-potential waveform, there is a linear correlation between peak area and concentration over two to three orders of magnitude for nine aminoglycoside antibiotics with a correlation coefficients better than 0.998 and the detection limits measured as three times the peak height signal-to-noise ratio for the nine aminoglycoside antibiotics were in the range of 0.0198-0.889 microg/mL. The proposed method had been used to analyze real gentamicin sulphate drug sample.

Aminoglycosides↗

PubMed2006

Repeated inhalation of toluene by rats performing a signal detection task leads to behavioral tolerance on some performance measures.

Previous work showed that trichloroethylene (TCE) impairs sustained attention as evidenced by a reduction in accuracy and elevation of response latencies in rats trained to perform a visual signal detection task (SDT). This work also showed that these effects abate during repeated exposures if rats inhale TCE while performing the SDT. The present experiment sought to determine whether toluene, another commonly-used solvent, would induce tolerance similarly if inhaled repeatedly during SDT testing. Sixteen male, Long-Evans rats were trained to perform the SDT. Upon completion of training, rats were divided into 2 groups. In Phase I, concentration-effect functions were determined for toluene (0, 1200, 1600, 2000, 2400 ppm) in both groups. Toluene reduced the proportion of correct responses [P(correct)], and increased response time (RT) and response failures. In Phase II, Group-Tol inhaled 1600 ppm toluene while Group-Air inhaled clean air during 11 daily SDT sessions. In Group-Tol the effect of toluene on P(correct) abated after 3 days, while RT remained elevated for the duration of the repeated exposures. In Phase III, toluene concentration-effect functions were re-determined for both groups. Group-Air remained impaired on all test measures, whereas for Group-Tol, toluene did not reduce P(correct), but continued to increase RT. These data confirm our previous hypothesis that animals can develop tolerance to chemical exposures that impair appetitively-motivated behaviors if that impairment leads to loss of reinforcement.

Administration, Inhalation↗

PubMed2005

Performance characteristics of an enzyme-linked immunosorbent assay performed in milk for the detection of liver fluke (Fasciola hepatica) infection in cattle.

AIM: To determine the performance characteristics of an enzyme-linked immunosorbent assay (ELISA) for the detection of antibodies against liver fluke (Fasciola hepatica) in bovine milk. METHODS: Serum and milk from liver fluke infected and non-infected cattle was assayed in a commercially available enzyme-linked immunosorbent assay. Serum test results were used to determine the "gold standard" infection status of cattle and milk ELISA results assessed by ROC analysis. RESULTS: ROC analysis suggested changes to the ELISA protocol, arriving at milk dilutions assayed considerably higher than those suggested by the manufacturer. With those changes, the ELISA performed with high sensitivity and specificity, 95 and 98.2%, respectively, for individual bovine milks (relative to sera). For bovine tank milks, sensitivity was lower, with bulk milks only testing positive if 60% or more of cattle milking in the herd were infected. CONCLUSIONS: The analysis of the ELISA's performance when used on individual bovine milks demonstrated high sensitivity and specificity. ROC analyses optimised the assay conditions and cut-off point suggested by the manufacturer for this commercial diagnostic assay. This would help with the identification and control of fasciolosis, enabling simpler sample collection.

Animals↗

PubMed2000

Safety and efficacy of percutaneous coronary interventions performed immediately after diagnostic catheterization in northern new england and comparison with similar procedures performed later.

"Ad hoc" percutaneous coronary interventions (PCIs)-those performed immediately after diagnostic catheterization-have been reported in earlier studies to be safe with a suggestion of higher risk in certain subgroups. Despite increasing use of this strategy, no data are available in recent years with new device technology. We studied use of an ad hoc strategy in a large regional population to determine its use and outcomes compared with staged procedures. A database from the 6 centers performing PCIs in northern New England and 1 center in Massachusetts was analyzed. During 1997, excluding only patients requiring emergency procedures or those with a prior PCI, 4,136 PCIs were performed, 1,748 (42.3%) of these being ad hoc procedures. Patients having ad hoc procedures were less likely to have peripheral vascular disease, renal failure, prior myocardial infarction, or coronary artery bypass surgery, congestive heart failure, or poor left ventricular function, and more likely to have received preprocedural intravenous heparin or nitroglycerin or to have required an urgent procedure. Narrowings treated during ad hoc procedures were less frequently types B and C or in saphenous vein grafts. Adjusted rates of clinical success were not different between ad hoc and non-ad hoc procedures (93.7% vs 93.6%); there was no difference in the incidence of death (0.6% vs 0.5%), emergency (0. 9% vs 0.8%) or any (1.4% vs 0.8%) coronary artery bypass surgery, or myocardial infarction (2.6% vs 2.0%). As currently practiced in our region, ad hoc intervention is used selectively with outcomes similar for ad hoc and non-ad hoc procedures.

Angina Pectoris↗

PubMed1999

Testing a motor performance series and a kinematic motion analysis as measures of performance in high-functioning stroke patients: reliability, validity, and responsiveness to therapeutic intervention.

OBJECTIVE: To assess measurement properties of motor performance tests when used with high-functioning stroke patients. DESIGN: Test-retest reliability study with an interval of 2 days; responsiveness study with assessment before and after training; validity study assessing the tests' ability to discriminate between the high-functioning stroke patients and healthy subjects. SETTING: Referral center for neurorehabilitation. PARTICIPANTS: Twenty-nine high motor-functioning stroke patients and 20 healthy control subjects. INTERVENTION: Two special training sessions per day on 5 consecutive days, plus regular therapy. OUTCOME MEASURES: Scores on the motor performance series, a two-dimensional tracking test, and a kinematic task analysis. RESULTS: All tests (except the bimanual test) were able to document performance deficits with these patients and showed a moderately high to high test-retest reliability without systematic trend from test to retest (intraclass correlation coefficients for main variables, .61 to .89). The kinematic task especially demonstrated changes after training (standardized response means for timing variables, .53 to .66). A subset of variables indicated a modifying effect of limb side, age, and gender. CONCLUSION: All tests (except the bimanual test) can be used for both cross-sectional and follow-up group studies with high-functioning stroke patients. Measurement properties and the lack of comprehensive normative data limit their use with individual patients.

Adult↗

PubMed2006

Mental rotation test performance in four cross-cultural samples (n = 3367): overall sex differences and the role of academic program in performance.

Two meta-analyses (Linn and Petersen, 1985; Voyer et al., 1995) discuss variables that affect mental rotation performance but they do not mention a potentially important variable, the Academic Program in which students are enrolled. Sex differences in brain size have been related to sex differences in spatial performance (e.g., Falk et al., 1999) and thus it is important to know whether mental rotation performance shows a significant interaction between Sex and Academic Program. To put our understanding of the Academic Program effect on a firmer empirical footing, we conducted a large scale multicultural study, with samples from Canada, Germany and Japan, using identical test procedures in all studies. Significant main effects for Sex and Academic Program were found in all four studies, with large effect sizes for Sex and medium to large effect sizes for Academic Program (based on Cohen's d). No significant interactions between these variables were found in the four samples. Our demonstration of a reliable Academic Program effect has clear and important pragmatic implications for a broad range of work on spatial ability and its interpretation.

Adolescent↗

PubMed1998

Microsurgical tubal anastomoses performed as an outpatient procedure by minilaparotomy are less expensive and as safe as those performed as an inpatient procedure.

OBJECTIVE: To determine the cost-effectiveness, safety, and success of microsurgical tubal anastomoses performed by minilaparotomy as an outpatient. DESIGN: Retrospective. SETTING: Military tertiary care medical center. PATIENT(S): Seventy consecutively seen women of reproductive age who were undergoing surgical reversal of sterilization from August 1, 1993, through August 1, 1995. INTERVENTION(S): Microsurgical sterilization reversal by minilaparotomy was performed as an inpatient (group 1, 47 patients) or as an outpatient (group 2, 23 patients). MAIN OUTCOME MEASURE(S): Cost, complication rate, pregnancy rate. RESULT(S): The procedure cost more for inpatients ($3,116) than for outpatients (!,456). Pregnancy rates were similar (56% in group 1 vs. 75% in group 2). There was only one complication in the series. CONCLUSION(S): Outpatient microsurgical sterilization reversal performed by minilaparotomy is as safe and effective as the inpatient procedure and is less expensive.

Adult↗

PubMed1990

Factors influencing the performance of peptide mapping by reversed-phase high-performance liquid chromatography.

Factors controlling the performance of peptide mapping on reversed-phase columns were systematically evaluated. Performance criteria included resolution (peak capacity and selectivity), system reproducibility, sensitivity and analysis speed. Column configuration, characteristics of packing materials, mobile phase composition, operating variables and instrumental designs were found to influence the performance of peptide mapping. Considerations for peptide identification techniques are discussed.

Chromatography, High Pressure Liquid↗

PubMed1977

Quantitation with high-performance thin-layer chromatography and programmed multiple development with high-performance micro-thin-layer material for drug analyses in biological fluids.

The programmed multiple development thin-layer chromatography (PMD-TLC) technique was compared with the conventional chromatographic technique on both normal and HPTLC plates. The potency of this high-performance TLC is illustrated and discussed by means of the data obtained with the determination of digitoxin in human serum. Improvement of the efficiency of TLC, resulting in a better resolution and sensitivity with PMD-TLC using using HPTLC plates, makes this high-performance TLC technique comparable to high-performance liquid chromatography. This TLC approach might lead to a sensitive, rapid, selective and simply assay for routine serial analyses and, because of its specificity and flexibility, it may facilitate drug interaction studies.

Chromatography, High Pressure Liquid↗

PubMed2000

Performance of experimental sample injectors for high-performance liquid chromatography microcolumns.

An experimental injector for HPLC microcolumns and a 3-nl conductivity detector connected directly to the injector outlet with a 19-nl tube were used to study injector dispersion, guide the design of improved injectors, and suggest appropriate injection techniques. With regard to the small injection volumes required when no on-column concentration technique is used, we show that in some circumstances: (i) there are two volumes to be considered, the sample volume (that which is intended to be injected) and the effective injection volume (that which contains all the sample after it has completely emerged from the injector). Due to dispersion, the latter is often many times the former. An injector performance factor is defined as the ratio of the two volumes. (ii) A smaller sample chamber volume in an injector does not necessarily produce a proportionately smaller effective injection volume, in which case there is a reduction of peak height that degrades sensitivity without a commensurate reduction in peak width that would improve resolution. (iii) Adjusting the geometry of the sample chamber and stator passage can significantly improve injector performance, as illustrated for sample volumes from 2 nl to 1 microl. (iv) In some cases, reducing the diameter of an injector passageway in an attempt to reduce dispersion actually causes performance to worsen.

Chromatography, High Pressure Liquid↗