Toward solving the inferential problem in laterality research: effects of increased reliability on the validity of the dichotic listening right-ear advantage.

As noted by Satz, the prevalence of lateralized language in the general population is underestimated substantially by the proportion of people who show the typical asymmetry on a laterality task. In a series of two dichotic listening experiments with a total of 171 right-handers and 170 left-handers, we tested the hypothesis that increased reliability of measurement will lead to increased classification accuracy. Experiment 1 showed that neither the frequency nor magnitude of the right-ear advantage (REA) for fused rhyming words increased as the number of trials increased from 120 to 480. Ear-difference scores were highly reliable (r = .85), even when based on 120 trials. Experiment 2, which involved lists of dichotic word pairs, yielded similar results. Even though retest reliability of the ear-difference score for 132 word pairs was only .45, neither the incidence nor strength of the REA increased significantly when the number of pairs was increased to 528. The results indicate that the poor classification accuracy of dichotic listening tasks cannot be attributed to unreliability.

Worldwide trends and developments in social security, 1983-85.

This article highlights the major developments and trends in social insurance programs that are presented in detail in the 1985 edition of Social Security Programs Throughout the World. The data in that reference book reflect the fact that as countries have adapted to the slow economic growth in recent years, increased emphasis has been placed on the cost effective use of social security funds. Some industrialized countries have restructured benefit provisions and reallocated resources among programs and beneficiaries to target benefits for specific groups. In the developing nations, the introduction of additional programs and expanded benefits continued on a limited scale amidst widespread concern about maintaining the real value of benefits after years of high inflation.

Digital subtraction angiography: principles and potential applications in emergency medicine.

Digital subtraction angiography (DSA) is a new computer-assisted process which enables visualization of arterial structures after intravenous injection of contrast material. Technical requirements of the process mandate total patient cooperation during the filming sequence, which generally lasts five to ten seconds. Because of lower spatial resolution compared with conventional angiography, and difficulty with vessel overlap as a result of nonselective opacification, DSA has not supplanted conventional angiography in evaluation of traumatic vascular injuries. The technology of DSA, currently accepted uses, and potential future uses of DSA are discussed. Future improvements in DSA promise to make it more amenable to the evaluation of traumatic vascular injuries.