Subject assessment methods

Given the mixed results in the literature, it is difficult to know just how caffeine does affect memory. To some extent, the differential effects may depend on the memory assessment method (recall or recognition) and the time frame (immediate or delayed). Gender differences may also cloud the picture, as discussed above. Even when these differences are taken into account, however, unexplained discrepancies remain. One partial explanation may be that the differential effects of caffeine are a function of the subject s memory load. For example, Anderson65 found that caffeine enhanced low load memory tasks but was detrimental in high load tasks. This could be due to the increased arousal induced by the high load task, which, in the presence of caffeine, could produce overarousal. The drop in arousal output as the subject crossed the peak of the inverted U-shaped function could cause the memory deficits observed in some studies. 

As seen above, all official methods of analysis are required to include precision data. These may be obtained by subjecting the method to a collaborative trial conforming to an internationally agreed protocol. A collaborative trial is a procedure whereby the precision of a method of analysis may be assessed and quantified. The precision of a method is usually expressed in terms of repeatability and reproducibility values. Accuracy is not the objective. 

Reference authors/year Number of subjects tested Method of assessment Results Summary comments... 

The last two decades have seen the introduction of several distinct functional imaging techniques that can be used to investigate centrally active compounds working in the brain in vivo. These techniques provide windows through which to observe phenomena in the intact and fully functional central nervous system. When applied to studies with human volunteers or patients one can obtain information that cannot be extrapolated from animal models, and from areas such as the brain and neurotransmitter systems that would otherwise be inaccessible in vivo. When combined with peripheral measurements and objective and subjective assessments of behavior, these methods can be used to explore how psychopharmaceuticals influence central nervous svtem activity and behavior. Moreover, compounds with a known mechanism of action can be employed as tools to understand how different elements of the central nervous system work. 

De Man (1983) has reviewed this property of fats. Consistency is defined as (1) an ill-defined and subjectively assessable characteristic of a material that depends on the complex stress-flow relation or as (2) the property by which a material resists change of shape. Spreadabil-ity, a term used in relation to consistency, is the force required to spread the fat with a knife. The definition is similar to that for hardness the resistance of the surface of a body to deformation. The most widely used simple compression test in North America is the cone penetrometer method (AOCS Method Cc 16-60, 1960). More sophisticated rheological procedures are also available. Efforts have been made to calibrate instrumental tests with sensory response. With the cone penetrometer method, penetration depth is used as a measure of firmness. Hayakawa and De Man (1982) studied the hardness of fractions obtained by crystallization of milk fat. Hardness values obtained with a constant speed penetrometer reflected trends in their TG composition and solid fat content. 

ITURrecBSl 116, 1994] ITURrecBSl 116 (1994). Methods for the subjective assessment of small impairments in audiosystems including multichannel sound systems. ITU-R. Recommendation BS. 1116. 

Methods of assessing rebound and withdrawal in more clinically relevant terms have been available for many years (e.g., [8]). In the past decade, regulatory authorities have insisted on discontinuation studies after short-term use as well as long-term maintenance or relapse prevention. This applies to hypnotics in equal force despite most product licences now restricting hypnotic use to short-term (2 1 weeks) use. An adequate number of subjects, normal and insomniac, must be studied. Rebound needs assessment over more than one night, with a variety of techniques including PSG, activity meters, and subjective reports. Standard sleep questionnaires can be used for the subjective assessments. 

Topical dorzolamide does not appear to cause a change in retinal circulatory variables, including venous diameter and volumetric blood flow rate, after a single dose in normal subjects. The drug also does not have any apparent effect on retrobulbar hemodynamics as determined by color Doppler imaging. In some studies, however, improvements in retinal, choroidal, and retrobulbar blood flow as determined by various assessment methods and hemodynamic markers demonstrate that dorzolamide alone or in combination therapy may improve ocular blood flow in patients with glaucoma and ocular... 

It is necessary to study stability in solution in the solvent used to prepare sample solutions for injection in order to establish that the sample solution composition, especially the analyte concentration, does not change in the time elapsed between the preparation of the solution and its analysis by HPLC. This is a problem for only a few types of compound (e.g. penicillins in aqueous solution) when the sample solution is analysed immediately after the preparation of the sample solution to be injected. The determination of stability in solution is more of an issue when sample solutions are prepared and then analysed during the course of a long autosampler run. While the acceptance criteria for stabUity in solution may be expressed in rather bland terms by making a statement such as, e.g. the analyte was sufficiently stable in solution in the solvent used for preparing sample solutions for reliable analysis to be carried out , in practice it has to be shown that within the limits of experimental error, the result of the sample solution analysis by the HPLC method is the same for injections at the time for which stability is being validated as for injections immediately subsequent to the sample solution preparation. While this may be done by a subjective assessment of results with confidence limits, strictly speaking a statistical method known as the Student s t-test should be used. 

Selecting variables is difficult and yet is crucial to the success of the monitoring exercise. One way is to define valued ecosystem components and construct a matrix of interactions between causes and effects. These interactions are then scored for magnitude and relative importance. Those which show the greatest effects are then considered as monitoring variables. This system is used effectively at present for environmental impact assessment in North America and Europe. At present it can be criticised on the grounds of subjective assessment of importance and magnitude, but there are no methods in which environmental quality determinations such as these can be made more independent. 

There are also other BE-type assessments. Interaction studies assess the influence on bioavailability by other individual factors, such as food, alcohol, or other drugs. Such studies are usually single-sequence crossover, but the assessment method remains the same—whether confidence intervals of AUC and Cmax ratios fall within (0.80, 1.25). The same can be said of PK similarity assessments between subject populations, for example, healthy volunteers versus patients. The assessment method is the same as that used for BE, but important differences remain. In typical BE studies, subjects are densely sampled so that individual PK parameters, AUC and Cmax, can be determined with precision. PK similarity assessments are concerned with the differences in different populations, instead of formulations. The assessments are usually based on multiple (parallel) studies, as crossover studies are not possible, and sequence and period effects are not considered. Assessments involve obtaining estimates of average PK parameters in the populations and the 90% confidence intervals for the ratios of the average PK parameters. 

Comparison of the ratings of experienced raters with previously recorded industrial hygiene measurements for occupations in Australia Estimation of the levels of exposure misclassification by expert assessment in a study of lung cancer in central and eastern Europe and Liverpool Application of Bayesian framework for retrospective exposure assessment of workers in a nickel smelter Determination of the level of information required by industrial hygienists to develop reliable exposure estimates Explanation of new framework to obtain exposure estimates through the Bayesiem approach Validation of a new method for structured subjective assessment of past concentration... 

Cherrie, J. W., and Schneider, T. (1999). Validation of a new method for structured subjective assessment of past concentrations. Ann Occup Hyg 43, 235-245. 

Retrospective dietary-assessment methods are simpler and less expensive than prospective and duplicate-diet methods, and therefore are used more often as the basis of dietary expostrre assessments. Food-fiequency studies take the form of participants identifying their typical fish consrrmption (e.g., How many times per week/month do you usually eat fish AT). Diet histories involve recollection of specific meals over a specific time (e.g. 24-hr or 1-week periods). In the studies mentioned above, Sherlock et al. (1982) and Haxton et al. (1979) used retrospective assessment of typical consumption to preselect subjects. In a recent study of MeHg exposure among pregnant women in New Jersey (Stem et al. 2000), participants were asked to identify their typical consumption frequency and typical portion size of 17 species of fish and... 

Of the three methods, the first, or checklist technique, has the greatest tendency to make subjects introspective regarding their symptoms. Not surprisingly, this approach elicits the largest number of adverse experience reports. Regardless of the method used, however, it is imperative that the questions be applied in the same way at each subject assessment, preferably by the same person, for the duration of the trial. It is also recommended that subjects be carefully questioned prior to administration of investigational products. It is remarkable how many so-called adverse reactions are, in fact, symptoms of other conditions present before the trial treatment starts, and therefore the principle of collecting adverse experiences becomes even more valuable. 

In general, there is an art and a science to molecular mechanics parameterization. On one extreme, least-squares methods can be used to optimize the parameters to best fit the available data set, and reviews on this topic are avail-able. Alternatively, parameters can be determined on a trial-and-error basis. The situation in either case is far from straightforward because the data usually available come from a variety of sources, are measured by different kinds of experiments in different units, and have relative importances that need subjective assessment. Therefore, straightforward applications of least-squares methods are not expected to give optimum results. 

Previous studies investigating dietary intake of micronutrients have reported that the dupficate portion technique offers the most accurate estimation. A study comparing dietary assessment methods to measure selenium intake concluded that diet record assessment was not adequate for predicting selenium intakes of individuals, and that duplicate diet analysis remains the recommended measure for research purposes (Duffield and Thomson, 1999). Furthermore, Koutras et al. (1970) state that if iodine intake is to be measured, the best method is the dupficate portion technique. However, the dupficate portion technique is labor intensive and requires a significant amount of subject commitment therefore, its use is usually restricted to small groups and data are usually collected over a short period of time. 

Study Location Dietary assessment method (days) subjects (M F) Male Female... 

An increase in precision may be achieved by increasing the number of subjects, although more involved dietary assessment methods, such as the duplicate portion technique, are labor intensive and require a significant amount of subject commitment therefore, their use is usually restricted to small groups and data are collected over a short period of time (Petersen and Barraj, 1996). However, short time periods will miss any seasonal differences in the iodine content of foods that may occur. Seasonal variations were minimized in the Waldmann study, as 7-day FFQs were completed in both the autumn and spring seasons. 

Our consumer research suggests that hair shine is a more meaningful cosmetic term to consumers than luster. The word luster is used more frequently in scientific works on textile materials. In most of our work, the objective was to develop methods to correlate with the consumers subjective assessment of hair shine. Therefore, the term hair shine is used in this discussion. 

---