Sensory testing subjects

Currently, treatment of DSP and ATN is similar to many other neuropathies that have predominantly painful sensory involvement (Mendell and Sahenk 2003 Gonzalez-Duarte et al. 2007). It is purely symptomatic as there are no proven regenerative therapies to reverse the underlying process. An 8-month prospective pilot study reported an improvement in subjective quantitative sensory testing (QST) in HIV-infected patients who responded to HAART (Martin et al. 2000). The patients who did not respond to HAART did not show any improvements in QST. It is possible that suppression of viral load will slow the progression of DSP. Some studies have found a correlation between viral load and incidence (Childs et al. 1999), or severity (Simpson et al. 2002) of sensory neuropathy. Others, however, did not find any correlation between plasma viral loads and incidence of DSP or ATN (Brew et al. 2003). 

In paired comparison tests two different samples are presented and one asks which of the two samples has most of the sensory property of interest, e.g. which of two products has the sweetest taste (Fig. 38.3). The pairs are presented in random order to each assessor and preferably tested twice, reversing the presentation order on the second tasting session. Fairly large numbers (>30) of test subjects are required. If there are more than two samples to be tested, one may compare all possible pairs ( round robin ). Since the number of possible pairs grows rapidly with the number of different products this is only practical for sets of three to six products. By combining the information of all paired comparisons for all panellists one may determine a rank order of the products and determine significant differences. For example, in a paired comparison one compares three food products (A) the usual freeze-dried form, (B) a new freeze-dried product, (C) the new product, not freeze-dried. Each of the three pairs are tested twice by 13 panellists in two different presentation orders, A-B, B-A, A-C, C-A, B-C, C-B. The results are given in Table 38.3. 

The AEGL-1 value was based on the observation that exercising healthy human subjects could tolerate exposure to concentrations of 500 or 1,000 ppm for 4 h with no adverse effects on lung function, respiratory symptoms, sensory irritation, or cardiac symptoms (Utell et al. 1997). The exercise, which tripled the subjects minute ventilation, simulates an emergency situation and accelerates pulmonary uptake. Results of the exposure of two subjects for an additional 2 h to the 500-ppm concentration and the exposure of one subject to the 1,000-ppm concentration for an additional 2 h failed to elicit any clear alterations in neurobehavioral parameters. The 4- or 6-h 1,000-ppm concentration is a NOAEL in exercising individuals, there were no indications of response differences among tested subjects, and animal studies indicate that adverse effects occur only at considerably higher concentrations, so the 1,000-ppm value was adjusted by an uncertainty factor (UF) of 1. The intraspecies UF of 1 is supported by the lack of adverse effects in patients with severe... 

Sensory Test - The choicest of the tested materials are now subjected to an actual Utility Test in a food system. These will include both the successes and the failures of the Model Test, with a range of values of significant variance. The foods prepared are then tested by a purely sensory approach. 

Utility tests. By definition, these are actual food formulations copying accepted food preparations. As mentioned above, when Model Tests are designed, the range of products undergoing the test should be wide enough to include some failures. In some cases, a Utility Test is employed that substitutes objective evaluation systems for sensory ones. This reduces the time of the test and its cost. However, only those objective tests previously found to be well correlated with sensory tests should be employed. Eventually a sensory test has to be performed. No food product should be marketed without a final utility test employing subjective evaluations. 

Sensory evaluation (sensory science) is a scientific discipline that concerns the presentation of a stimulus (in this case a flavor compound, a flavor, or flavored product) to a subject and then evaluation of the subject s response. The response is expressed as, or translated into, a numerical form so that the data can be statistically analyzed. The sensory scientist then collaborates with the research or product development team to interpret the results and to reach decisions. Sensory scientists stress that decisions, such as product formulation, are made by people, not by the results of a sensory test, although such results may provide powerful guidance in the decision-making process. 

Sensory methods are often criticized as being subjective techniques. Part of the problem ties with the failure to acknowledge that two distinct types of sensory tests... 

Statistics are used in sensory testing to determine whether the responses from panelists are sufficiently similar or represent a random occurrence. Knowing the degree of similarity enables one to draw conclusions about the samples being tested with some measure of confidence in the context of that population of subjects and in the case of consumer-oriented tests to the population in general. Thus, it is important that appropriate statistical methods be applied to sensory data to satisfy the test objectives. For a more thorough discussion of the appropriate statistical methods for each of the various sensory tests, refer to Stone and Sidel (1) and ASTM (2). 

Method validation is often based on the combined use of validation procedures. The validation used can be direct or comparative. The selection of the validation procedures should also be justified on a cost-benefit basis as long as the fitness-for-purpose is maintained. Focusing the effort on the most critical factors affecting the test method will lead to a different solution for the validation of exact physical and chemical test methods as compared to that for product or subjective testing. For example, in the validation of ergonomics and sensory test methods not all possibilities are applicable. 

Quantitative somatosensory testing (QST) uses calibrated tools to assess the function of all the sensory modalities. The smaller caliber nerves are evaluated by measuring pain and temperature (hot and cold) thresholds, and larger caliber nerves are evaluated by measuring the thresholds for perception of vibration, joint position, and touch. This is done by touching the patients skin with stimuli of defined characteristics, such as a computer-controlled probe that can heat or cool to specific temperatures. The effectiveness of QST is limited because it requires subject cooperation and is inherently subjective, as it relies on the reported interpretation of sensory stimulation from the subject. This also influences reproducibility of this sensory test (Fink and Qaklander, 2006). 

Sensory Analysis involves using human subjects as a measuring tool. This presents an immediate problem, as individuals are innately variable, not only as a result of their experiences or expectations, but also as a result of their sensitivity. Thus, each person could genuinely perceive the same product quite differently. It is therefore essential in every sensory test that all variables, except that actually under test, are as carefully controlled as possible to minimize this variability. 

In sensory evaluation consumers estimate fruit firmness on the basis of the deformation resulting from physical pressure applied by the hand and fingers. The toughness or tenderness of meat is subjectively evaluated in terms of the effort required for the teeth to penetrate and masticate the flesh tissues. Therefore, determination of rheological properties of foodstuffs is important in evaluation of consumer-determined quality by correlating rheological measurements with sensory tests. 

Organoleptics (taste and odor) The relative sensory effect of aldehydes emanating from sorbitol-clartfled material, for example, can be rated by human test subjects. 

We selected CBA/J mice as test subjects because, of the 28 inbred strains of mice that were tested, members of this strain proved to be the most sensitive to the boar sex-pheromone, androstenone (5 -androst-16-en-3-one Voznessenskaya, Parfyonova Wysocki., 1995). For comparison, results of tests with NZB/BINJ mice were made (these mice were selected because they were among the many lines that were insensitive to androstenone). Animals were kept under standard vivarium conditions, e.g., 12 12 light.dark cycle, with controlled temperature (typically 25°C) and humidity, in plastic cages, one animal per cage. Tests were performed both in Philadelphia, at the Monell Center, and in Moscow, at the A.N. Severtzov Institute of Ecology Evolution. Behavioral and biochemical analyses were undertaken to evaluate the effects of exposure to androstenone on threshold sensitivity to androstenone and potential biochemical correlates within the olfactory and vomeronasal sensory epithelia. 

From the perspective of rapid methods, the ability to screen and qualify subjects in two or three sessions is a small price to pay for having a pool of qualified subjects. The argument that one can achieve the same level of confidence using a statistical analysis based on various assumptions about behavior is a risky argument a sensory test is a behavioral test and use of statistics enables one to summarize the information and reach a conclusion in terms of risk associated with using qualified subjects. 

In the context of an ageing population, the development of products meeting the elderly s needs and expectations becomes a major challenge for the food industry as well as for society. As a result, it is highly important to use sensory assessment tools with elderly subjects as their perceptions may not be interchangeable with those of adults who are under 60 years of age (Murray et al., 2(X)1). However, few sensory descriptive studies exist which include a panel of older subjects, and very few publications have compared the performances of young and elderly subjects in sensory tests. 

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