The performance of South African English first language child speakers on a "low linguistically loaded" central auditory processing test protocol

The lack of standardized tests of central auditory processing disorder (CAPD) in South Africa (SA) led to the formation of a SA CAPD Taskforce, and the interim development of a "low linguistically loaded" CAPD test protocol using test recordings from the 'Tonal and Speech Materials for Auditory Perceptual Assessment Disc 2.0'. This study inferentially compared the performance of 16 SA English first, and 16 SA English second, language adult speakers on this test protocol, and descriptively compared their performances to previously published American normative data. Comparisons between the SA English first and second language speakers showed a poorer right ear performance (p < .05) by the second language speakers on the two-pair dichotic digits test only. Equivalent performances (p < .05) were observed on the left ear performance on the two pair dichotic digits test, and the frequency patterns test, the duration patterns test, the low-pass filtered speech test, the 45% time compressed speech test, the speech masking level difference test, and the consonant vowel consonant (CVC) binaural fusion test. Comparisons between the SA English and the American normative data showed many large differences (up to 37.1% with respect to predicted pass criteria as calculated by mean-2SD cutoffs), with the SA English speakers performing both better and worse depending on the test involved. As a result, the American normative data was not considered appropriate for immediate use as normative data in SA. Instead, the preliminary data provided in this study was recommended as interim normative data for both SA English first and second language adult speakers, until larger scale SA normative data can be obtained.

Distortion product otoacoustic emissions in children at school entry: A comparison with pure tone screening and tympanometry results

This study examined the test performance of distortion product otoacoustic emissions (DPOAEs) when used as a screening tool in the school setting. A total of 1003 children (mean age 6.2 years, SD = 0.4) were tested with pure-tone screening, tympanometry, and DPOAE assessment. Optimal DPOAE test performance was determined in comparison with pure-tone screening results using clinical decision analysis. The results showed hit rates of 0.86, 0.89, and 0.90, and false alarm rates of 0.52, 0.19, and 0.22 for criterion signal-to-noise ratio (SNR) values of 4, 5, and 11 dB at 1.1, 1.9, and 3.8 kHz respectively. DPOAE test performance was compromised at 1.1 kHz. In view of the different test performance characteristics across the frequencies, the use of a fixed SNR as a pass criterion for all frequencies in DPOAE assessments is not recommended. When compared to pure tone plus tympanometry results, the DPOAEs showed deterioration in test performance, suggesting that the use of DPOAEs alone might miss children with subtle middle ear dysfunction. However, when the results of a test protocol, which incorporates both DPOAEs and tympanometry, were used in comparison with the gold standard of pure-tone screening plus tympanometry, test performance was enhanced. In view of its high performance, the use of a protocol that includes both DPOAEs and tympanometry holds promise as a useful tool in the hearing screening of schoolchildren, including difficult-to-test children.

Tension regulation during lengthening and shortening actions of the human soleus muscle

In the present study we investigated tension regulation in the human soleus (SOL) muscle during controlled lengthening and shortening actions. Eleven subjects performed plantar flexor efforts on an ankle torque motor through 30 degrees of ankle displacement (75 degrees-105 degrees internal ankle angle) at lengthening and shortening velocities of 5, 15 and 30 degrees s(-1). To isolate the SOL from the remainder of the triceps surae, the subject's knee was flexed to 60 degrees during all trials. Voluntary plantar flexor efforts were performed under two test conditions: (1) maximal voluntary activation (MVA) of the SOL, and (2) constant submaximal voluntary activation (SVA) of the SOL. SVA trials were performed with direct visual feedback of the SOL electromyogram (EMG) at a level resulting in a torque output of 30% of isometric maximum. Angle-specific (90 degrees ankle angle) torque and EMG of the SOL, medial gastrocnemius (MG) and tibialis anterior (TA) were recorded. In seven subjects from the initial group, the test protocol was repeated under submaximal percutaneous electrical activation (SEA) of SOL (to 30% isometric maximal effort). Lengthening torques were significantly greater than shortening torques in all test conditions. Lengthening torques in MVA and SVA were independent of velocity and remained at the isometric level, whereas SEA torques were greater than isometric torques and increased at higher lengthening velocities. Shortening torques were lower than the isometric level for all conditions. However, whereas SVA and SEA torques decreased at higher velocities of shortening, MVA torques were independent of velocity. These results indicate velocity- and activation-type-specific tension regulation in the human SOL muscle.

Ramp and constant power trials produce equivalent critical power estimates

The standard critical power test protocol on the cycle prescribes a series of trials to exhaustion, each at a different but constant power setting. Recently the protocol has been modified and applied to a series of trials to exhaustion each at a different ramp incremental rate. This study was undertaken to compare critical power and anaerobic work capacity estimates in the same group of subjects when derived from the two protocols. Ten male subjects of mixed athletic ability cycled to exhaustion on eight occasions in randomized order over a 3-wk period. Four trials were performed at differing constant power settings and four trials on differing ramp incremental rates. Both critical power and anaerobic work capacity were estimated for each subject by curve fitting of the ramp model and of three versions of the constant power model. After adjusting for inter-subject variability, no significant differences were detected between critical power estimates or between anaerobic work capacity estimates from any model formulation or from the two protocols. It is concluded that both the ramp and constant power protocols produce equivalent estimates for critical power and anaerobic work capacity.

Effect of body position on transient evoked accoustic emissions: The clinical perspective

The present study investigated body position effects on transient evoked otoacoustic emission (TEOAE) recordings of clinical significance. Sixty adults (30 males, 30 females) were assessed using the Otodynamics ILO88 Analyzer in three positions (sitting, supine, and side-lying). Results indicated significant positional effects on the TEOAE parameters of A-B difference, noise, whole wave reproducibility, and response levels. These differences included higher noise levels in supine and side-lying positions in comparison to the upright sitting position. Lower whole wave reproducibility measurements, and higher response amplitudes, in the side-lying position compared with supine and seated positions were also observed. No significant effects were evident for signal-to-noise ratio or band reproducibility. Given the lack of significant body position effects on these latter parameters and the infrequent clinical use of the other parameters in isolation, there was no evidence to suggest the future need for major review of current pass/fail criteria or of the standard test protocol.

A rapid PCR protocol for marker assisted detection of heterozygotes in segregating generations involving 1BL/1RS translocation and normal wheat lines

A rapid and reliable polymerase chain reaction (PCR)-based protocol was developed for detecting zygosity of the 1BL/1RS translocation in hexaploid wheat. The protocol involved a multiplex PCR with 2 pairs of oligonucleotide primers, rye-specific Ris-1 primers, and consensus 5S intergenic spacer (IGS) primers, and digestion of the PCR products with the restriction enzyme, MseI. A small piece of alkali-treated intact leaf tissue is used as a template for the PCR, thereby eliminating the necessity for DNA extraction. The test is simple, highly sensitive, and rapid compared with the other detection systems of 1BS1RS heterozygotes in hexaploid wheat. PCR results were confirmed with AFLP analyses. Diagnostic tests for 1BL/1RS translocation based on Sec-1-specific ELISA, screening for chromosome arm 1RS controlled rust resistance locus Yr9, and the PCR test differed in their ability to detect heterozygotes. The PCR test and rust test detected more heterozygotes than the ELISA test. The PCR test is being used to facilitate S1 family recurrent selection in the Germplasm Enhancement Program of the Australian Northern Wheat Improvement Program. A combination of the PCR zygosity test with other markers currently being implemented in the breeding program makes this test economical for 1BL/1RS characterisation of S1 families.

Use of an accelerated chest pain assessment protocol in patients at intermediate risk of adverse cardiac events

Objective: To determine the feasibility, safety and effectiveness of a structured clinical pathway for stratification and management of patients presenting with chest pain and classified as having intermediate risk of adverse cardiac outcomes in the subsequent six months. Design: Prospective clinical audit. Participants and setting: 630 consecutive patients who presented to the emergency department of a metropolitan tertiary care hospital between January 2000 and June 2001 with chest pain and intermediate-risk features. Intervention: Use of the Accelerated Chest Pain Assessment Protocol (ACPAP), as advocated by the Management of unstable angina guidelines - 2000 from the National Heart Foundation and the Cardiac Society of Australia and New Zealand. Main outcome measure: Adverse cardiac events during six-month follow-up. Results: 409 patients (65%) were reclassified as low risk and discharged at a mean of 14 hours after assessment in the chest pain unit. None had missed myocardial infarctions, while three (1%) had cardiac events at six months (all elective revascularisation procedures, with no readmissions with acute coronary syndromes). Another 110 patients (17%) were reclassified as high risk, and 21 (19%) of these had cardiac events (mainly revascularisations) by six months. Patients who were unable to exercise or had non-diagnostic exercise stress test results (equivocal risk) had an intermediate cardiac event rate (8%). Conclusions: This study validates use of ACPAP. The protocol eliminated missed myocardial infarction; allowed early, safe discharge of low-risk patients; and led to early identification and management of high-risk patients.

Transient evoked otoacoustic emissions in adults: a comparison between two test protocols

This study compares the performance of the Quickscreen and Default protocols of the ILO-96 Otodynamics Analyzer in recording transient evoked otoacoustic emissions (TEOAEs) from adults using clinical decision analysis. Data were collected from 25 males (mean age = 29.0 years, SD = 6.8) and 35 females (mean age = 28.1 years, SD = 9.6). The results showed that the mean signal-to-noise ratios obtained from the Quickscreen were significantly greater than those from the Default protocol at 1,2, and 4 kHz. The comparison of the performance of the two protocols, based on the results using receiver operating characteristics curves, revealed a higher performance of the Quickscreen than the Default protocol at 1 and 4 kHz but not at 2 kHz. In view of the enhanced performance of the Quickscreen over the Default protocol in general, the routine use of the Default protocol for testing adults in audiology clinics should be reconsidered.

A Test of Performance of Breast MRI Interpretation in a Multicentre Screening Study

Objectives: The aim of this study was to assess the consistency and performance of radiologists interpreting breast magnetic resonance imaging (MRI) examinations. Materials and Methods: Two test sets of eight cases comprising cancers, benign disease, technical problems and parenchymal enhancement were prepared from two manufacturers' equipment (X and Y) and reported by 15 radiologists using the recording form and scoring system of the UK MRI breast screening study [(MAgnetic Resonance Imaging in Breast Screening (MARIBS)]. Variations in assessments of morphology, kinetic scores and diagnosis were measured by assessing intraobserver and interobserver variability and agreement. The sensitivity and specificity of reporting performances was determined using receiver operating characteristic (ROC) curve analysis. Results: Intraobserver variation was seen in 13 (27.7%) of 47 of the radiologists' conclusions (four technical and seven pathological differences). Substantial interobserver variation was observed in the scores recorded for morphology, pattern of enhancement, quantification of enhancement and washout pattern. The overall sensitivity of breast MRI was high [88.6%, 95% confidence interval (CI) 77.4-94.7%], combined with a specificity of 69.2% (95% CI 60.5-76.7%). The sensitivities were similar for the two test sets (P=.3), but the specificity was significantly higher for the Manufacturer X dataset (P

Time-reversal test for stochastic quantum dynamics

The calculation of quantum dynamics is currently a central issue in theoretical physics, with diverse applications ranging from ultracold atomic Bose-Einstein condensates to condensed matter, biology, and even astrophysics. Here we demonstrate a conceptually simple method of determining the regime of validity of stochastic simulations of unitary quantum dynamics by employing a time-reversal test. We apply this test to a simulation of the evolution of a quantum anharmonic oscillator with up to 6.022×1023 (Avogadro's number) of particles. This system is realizable as a Bose-Einstein condensate in an optical lattice, for which the time-reversal procedure could be implemented experimentally.

Apparent insensitivity of the hotplate latency test for detection of antinociception following intraperitoneal, intravenous or intracerebroventricular M6G administration to rats

Although morphine-6-glucuronide (M6G) has been shown to be analgesically active, the relative involvement of spinal and supraspinal structures in mediating M6G's pain-relieving effects following central and systemic administration to rats is unclear. As the tail flick and hotplate latency tests are reported to quantify antinociception mediated primarily by spinal and supraspinal mechanisms respectively, these methods were used to determine the comparative apparent levels of antinociception (expressed as percentage maximum possible effect, % MPE) achieved after M6G or morphine administration. Following i.v. or i.p. M6G (1.9-5.4 mu mol) dosing or i.p. morphine (10 mu mol) dosing, high levels of antinociception (>50% MPE) were achieved using the tail flick test whereas base-line levels of antinociception were observed 30 sec later in the same rats using the hotplate test. By contrast, antinociception evoked by i.v. morphine (10 mu mol) exceeded 50% MPE using both the hotplate and tail flick tests although the apparent potency was approximately 2.5 times greater using the tail flick test. After i.c.v. dosing, M6G (0.22-3.3 nmol) was significantly (P < .05) more potent when assessed using the tail flick compared with the hotplate test. Taken together, these data strongly indicate that following central and systemic administration, M6G's antinociceptive effects are mediated primarily by spinal structures whereas both spinal and supraspinal mechanisms contribute to systemic morphine's antinociceptive effects.

The Modified Card Sorting Test: Test-retest stability and relationships with demographic variables in a healthy older adult sample

Objectives. To investigate the test-retest stability of a standardized version of Nelson's (1976) Modified Card Sorting Test (MCST) and its relationships with demographic variables in a sample of healthy older adults. Design. A standard card order and administration were devised for the MCST and administered to participants at an initial assessment, and again at a second session conducted a minimum of six months later in order to examine its test-retest stability. Participants were also administered the WAIS-R at initial assessment in order to provide a measure of psychometric intelligence. Methods. Thirty-six (24 female, 12 male) healthy older adults aged 52 to 77 years with mean education 12.42 years (SD = 3.53) completed the MCST on two occasions approximately 7.5 months (SD = 1.61) apart. Stability coefficients and test-retest differences were calculated for the range of scores. The effect of gender on MCST performance was examined. Correlations between MCST scores and age, education and WAIS-R IQs were also determined. Results. Stability coefficients ranged from .26 for the percent perseverative errors measure to .49 for the failure to maintain set measure. Several measures were significantly correlated with age, education and WAIS-R IQs, although no effect of gender on MCST performance was found. Conclusions. None of the stability coefficients reached the level required for clinical decision making. The results indicate that participants' age, education, and intelligence need to be considered when interpreting MCST performance. Normative studies of MCST performance as well as further studies with patients with executive dysfunction are needed.

Critical values for unit root and cointegration test statistics - the use of response surface equations

This note considers the value of surface response equations which can be used to calculate critical values for a range of unit root and cointegration tests popular in applied economic research.

A test of competing explanations of compensation demanded

We find that prospect theory behavior is significantly more prevalent than utility theory behavior in experiments involving multiple, real items. In the experiments, subjects were endowed with three items and asked the minimum payments they required to be willing to return one, two, or three of them. Our key observation is that prospect theory implies concavity of compensation demanded, whereas utility theory implies convexity. We examine whether the compensation demanded is convex or concave in the number of items returned. (JEL C91).