A comparison of sniff bottle staircase and olfactometer-based threshold tests.

Olfactometers have been gaining popularity as research tools, but they have yet to replace established testing procedures in a variety of laboratory and clinical settings, including absolute threshold tests. In this research, we designed and operated a simple olfactometer with which to assess threshold. To do this, we used a method-of-adjustment test that was compared to the three-alternative forced choice ascending sniff bottle staircase method, which is currently a standard threshold test procedure. We found that the olfactometer threshold test correlated highly with the staircase method, and that it possessed suitable test-retest reliability. The advantages of the olfactometer threshold test include faster test time and reduced cleaning and reassembly demands. Future use of the olfactometer in olfactory identification and/or detection thresholds amongst odors is also outlined.

Evaluation of smoking on olfactory thresholds of phenyl ethyl alcohol and n-butanol.

The effect of smoking on the sense of smell remains inconclusive. Previous research suggests that this is due to idiosyncratic acuity dependent on the odorants used in testing. Specifically, it appears that smokers have reduced olfactory acuity to odorants found within cigarettes compared with odorants not within cigarettes. Given that some of these odorants are used in tomography and magnetic resonance imaging, an in-depth understanding of this phenomenon in smoking individuals is crucial. This study assesses the variation of olfactory thresholds in smokers based on selective impairment to two odors commonly used in olfactory testing - n-butanol and phenyl ethyl alcohol (PEA). We presented to 46 participants an 18 step, forced choice, three choice ascending staircase method sniff bottle threshold test using n-butanol and PEA. PEA is present in cigarettes while n-butanol is not. Therefore n-butanol is used as a covariate to control for variance explained by any general olfactory dysfunction. Using this method, we can focus solely on selective impairment. We discovered that n-butanol threshold scores were significantly different between smokers and nonsmokers. In addition, after using n-butanol as covariate, phenyl ethyl alcohol scores remained significantly different between groups. This data suggests that there is an extended impairment to odors within tobacco and this may explain a cause of the inconclusiveness of past research.

Tests for screening olfactory and gustatory function in school-age children.

OBJECTIVE: Determine the suitability of three tests based on the identification of familiar odors and tastes for the clinical assessment of olfaction and gustation in children. STUDY DESIGN AND SETTING: A total of 232 children aged 5 to 7 years from Sydney public schools and 56 adults aged 18 to 51 years participated in a cross-sectional study. RESULTS: The children demonstrated they can identify the majority of the 16 test odorants and 4 common tastes that describe gustatory function. The response distributions obtained for each test provide the basis for a set of normative data for young children. CONCLUSION: Olfactory and gustatory function can be determined in school-age children using the three tests described. SIGNIFICANCE: Currently no satisfactory clinical tests of olfaction and gustation for children or normative data are available. The present study resolves these shortcomings and provides normative data that can be used in the diagnosis of olfactory and gustatory impairment in school-age children.

Relationship between molecular structure, concentration and odor qualities of oxygenated aliphatic molecules.

Increasing the concentration of an odorant increases the number of receptor cells and glomeruli in the olfactory bulb that are stimulated, and it is commonly acknowledged that these represent increased numbers of receptor types. Currently, it is not known whether a receptor type is associated with a unique quality and a unique molecular feature of an odorant, or its activation is used by the brain in a combinatorial manner with other activated receptor types to produce a characteristic quality. The present study investigated the proposal that a molecular feature common to several aliphatic odorants and known to be the key feature required to stimulate the same mitral cells in the olfactory bulb results in a quality that is common to the odorants. Since the common structural feature may activate a specific receptor type possibly at a similar concentration, the qualities of the odorants were determined at seven concentrations where the lowest and highest concentrations were the detection threshold (DT) and 729DT of each subject. A list of 146 descriptors was used by 15 subjects to describe the qualities of each odorant at each concentration. The results indicate that each of the five odorants was characterized by different qualities and the qualities of four of the odorants changed with changes in concentration. Importantly, no quality common to each of the odorants that had the same molecular feature could be identified and it is proposed that identification of the odorants occurs via a combinatorial mechanism involving several types of receptors.

A psychophysical study of the relationship between temporal processing in odor mixtures and transduction pathways.

Depending on the odorant, transduction during the olfactory reception process is reported to be mediated by the second messengers cyclic adenosine 3',5'-monophosphate (cAMP) or inositol 1,4,5-triphosphate (IP(3)). The present study with humans investigates the relationship between temporal processing in mixtures and the type of transduction process used. The most common outcomes were reciprocal temporal interactions which were primarily dependent on odorant concentration and independent of the type of transduction process. The results are consistent with the bulk of evidence that each receptor neuron commonly has only one type of receptor.

Identification of the components of taste mixtures by adults and children.

Recently, it was reported that cognitive factors may have impeded the analysis of binary taste mixtures by 8- to 9-year-old children, resulting in them identifying only the strongest component in each mixture compared to adults who identified both components (Oram, Laing, Freeman, & Hutchinson, 2001). The current study aimed to overcome this limitation by employing different training procedures and different instructions when conducting the task. In particular, the training involved familiarization with the two stimuli at several levels of perceived intensity to facilitate identification of the varying levels of each stimulus in mixtures. Using a selective attention procedure, adults and children were required to identify the components of stimuli that contained water, sucrose (sweet), sodium chloride (salty), or were binary mixtures of these two tastants. Both groups were successful in identifying the component(s) in each stimulus, demonstrating the importance of appropriate training and test procedures when studying the sensory responses of children. Together with data from the earlier study by Oram et al. (2001) it is concluded that 8- to 9-year-olds have the cognitive skills to analyze taste mixtures in terms of the identity of the components and their perceived strengths.

The analysis of odor mixtures by humans: evidence for a configurational process.

Humans have a limited capacity to analyze odor mixtures with three to four being the maximum [Physiol Behav 46 (1989) 809.]. This study investigates the large loss of information about odor identity that occurs in mixtures and aims to determine the information on which identification and failure to identify is based. In Experiment 1, 14 subjects used a selective attention procedure to identify odorants in stimuli consisting of one to four components. As expected, substantial difficulties were encountered in identifying more than two odorants, and chance level scores were obtained for the group for each of the odorants in the quaternary mixture. In Experiment 2, 21 subjects used a profiling procedure consisting of 146 descriptors to describe the odor qualities perceived in the same stimuli used in Experiment 1. The results indicated that for some odorants, loss of a major characteristic quality occurred even in binary mixtures, but that many of the features of some odorants remained in the quaternary mixture. Comparison of the data from the two experiments indicated that identification of most of the prominent qualities of an odorant was not necessarily sufficient for identification of the odorant in a mixture. In contrast, the loss of some prominent features did not always result in non-identification. A configurational hypothesis of olfaction, analogous to that for facial and object recognition, is proposed to account for the data and the processes underlying odor identification in mixtures.

Temporal processing reveals a mechanism for limiting the capacity of humans to analyze odor mixtures.

Humans have great difficulty in analyzing odor mixtures. The present study investigates the role of temporal processing in mixture perception and its impact on human performance. The results indicate that in contrast to binary mixtures, the temporal order of the perception of components and their identity cannot be discerned in ternary mixtures. It is proposed that the primary cause of this inability is slow processing in olfactory working memory which limits the analysis of mixtures to about three components.

'Stories' or 'snapshots'? A study directed at comparing qualitative and quantitative approaches to curriculum evaluation.

The focus of this paper is a study designed to explore the validity of quantitative approaches of student evaluation in a pre-registration degree programme. As managers of the students' education we were concerned that the quantitative method, which used lecturer criteria, may not fully represent students' views. The approach taken is that of a process-type strategy for curriculum evaluation as described by Parlett and Hamilton (1972). The aim of the study is to produce illuminative data, or students' 'stories' of their educational experiences through use of semi-structured interviews. The results are then compared to the current quantitative measurement tools designed to obtain 'snapshots' of the educational effectiveness of the curriculum. The quantitative measurement tools use Likert scale measurements of teacher-devised criterion statements. The results of the study give a rich source of qualitative data which can be used to inform future curriculum development. However, complete validation of the current quantitative instruments used was not achieved in this study. Student and teacher agendas in respect of important issues pertaining to the course programme were found to differ. Limitations of the study are given. There is discussion of the options open to the management team with regard to future development of curriculum evaluation systems.

A limit in the processing of components in odour mixtures.

We investigated the hypothesis that physiological limitations restrict the ability of humans to identify components in an odour mixture. Subjects were trained to identify the test odours, and were required to detect a single highly familiar odorant in stimuli consisting of one, four, eight, twelve, and sixteen odorants by using a selective-attention procedure. The stimuli were delivered by a computer-controlled sixteen-channel air-dilution olfactometer which provided samples of each of the sixteen odorants to be of equal perceived intensity for each subject. Identification fell to chance level when sixteen odorants were present. It is proposed that the profound loss of information was primarily due to inhibition of olfactory receptor cells by the odorants through competitive mechanisms, and the subsequent loss of odour identity through changes in the spatial code that may be used to identify odorants.

Workplace health concerns: a focus group study.

Addresses the workplace health concerns of employees at an Acute Hospital Trust. The research conducted utilised a focus group methodology to investigate the health concerns of multidisciplinary groups of health care workers (n = 27). The findings indicate that the concern for the majority was workplace stress. Stressors that were identified as important to the groups were for example, the nature of the work they were undertaking, staffing levels, volume of the work, management styles and their work environments. Health promotion and prevention topics such as motivation and health status, smoking, alcohol and drug misuse, nutrition and weight control and physical exercise were seen of subsidiary concern. Limitations of the study are given. Future research in the subject area is identified.

Temporal processing of odor mixtures reveals that identification of components takes precedence over temporal information in olfactory memory.

Temporal processing of binary mixtures results in odorants being perceived in series separated by many hundreds of milliseconds. Since the odorant perceived first is the main suppressor, knowledge of the order of perception of two odorants can allow prediction of interactions in mixtures. The present study investigated the temporal coding of ternary mixtures composed of carvone, coniferan and triethylamine, and citralva, lillial and triethylamine using a specially constructed air-dilution olfactometer. The results indicated that even though each of the components could be readily identified in ternary mixtures, it was very difficult to indicate which odor was perceived first, with chance scores being recorded. The same outcome occurred even when the 'slowest' odorant was delivered 600 ms after the 'fastest' to the nose. It is proposed that olfactory memory gives precedence to identification of the components of mixtures rather than to their order of perception when more than two odorants are in a mixture.

Modulation of anxiety-related behaviours following lesions of the prelimbic or infralimbic cortex in the rat.

A series of experiments examined behavioural and autonomic aspects of stress and anxiety in rats subjected to either: (1) electrolytic lesions of the infralimbic cortex subregion of the medial prefrontal cortex; (2) electrolytic lesions of the prelimbic cortex subregion of the medial prefrontal cortex; (3) sham lesions of infralimbic or prelimbic cortex (sham control); or (4) no lesions (control). In exploration-based models of anxiety, infralimbic- or prelimbic-lesioned rats spent less time in the centre of an open field and less time on the exposed arms of an elevated plus maze, indicating increased anxiety. Locomotor activity was normal in the lesioned rats when tested in a non-stressful enclosed environment. In a step-down passive avoidance task, infralimbic-lesioned rats stepped down more quickly than controls onto a grid floor where they had been shocked 24 h previously. Prelimbic-lesioned rats were no different to controls on this test, although they showed greater latencies to step down onto the grid floor during conditioning. In a final experiment, indirect calorimetry was used to show that both infralimbic- and prelimbic-lesioned rats have essentially normal alterations in oxygen consumption and energy substrate utilisation when exposed to brief footshock. Thus, the impaired passive avoidance in infralimbic-lesioned rats cannot be attributed to decreased nociception. It is concluded that both the prelimbic and infralimbic regions play a role in anxiety, and that this role may be subtly differentiated. In particular, the infralimbic cortex may have a specific role in mediating the inhibition of behaviours associated with aversive outcomes.

The role of the external examiner in the assessment of clinical practice.

In the first part of this paper we give a brief overview of the development of the different types of clinical assessment used in the UK. Some general problems related to the assessment of clinical practice are outlined. The second part of the paper focuses on the role of the external examiner in the clinical assessment of students. We outline some of the major problems we encountered as internal and external examiners on the same university-based course in which 'I-day' practical assessments were undertaken. We emphasize the particular problems of externally assessing the clinical practice component of the course in this manner and conclude that the continuous assessment model, while not without its own problems, is potentially a more effective approach to student assessment.

Conceptualization of differing levels of educational attainment: what are the characteristics of nurses and midwives who have undertaken diploma and degree educational programmes?

This paper looks at the differences in the characteristics of registered nurses and midwives who have achieved differing levels of educational attainment. A review of the pertinent literature demonstrates that there is little published material on this topic and therefore, proposals are put forward with regard to a conceptual model to frame outcome characteristics. The model is seen as being appropriate when trying to identify the different characteristics of nurses and midwives educated to diploma, degree, post-graduate diploma, masters and doctoral level. The model is subsequently applied to identifying core outcomes and composite statements of nurses and midwives who have undertaken diploma or degree programmes. Initial work examining the validity and reliability of the core outcomes and composite statements with regard to degree preparation is described. Areas for further research are also identified.

Examining the role of the practitioner-teacher in nursing.

This article examines the difficulties faced by specialist nurses when they attempt to combine practice and teaching roles. It gives a detailed analysis of the emergence of full-time practitioner-teachers in nursing, including the role of joint appointees. It is recommended that the practitioner-teacher role should be promoted, and this will necessitate research into the feasibility of such roles.

Integrating what is taught with what is practised in the nursing curriculum: a multi-dimensional model.

The discrepancy between nursing as it is taught in the classroom (theory) and nursing as it is experienced by students in the clinical setting (practice) has long been a source of concern to teachers, practitioners and learners. This paper provides an overview of the literature on the theory-practice gap, exploring some of the many reasons cited for its existence as well as suggested ways of bridging the gap. Drawing upon the findings, a comprehensive and multi-dimensional model designed to integrate theory and practice of nursing is proposed for use by curriculum planners. Fundamental to the model is the notion of collaboration between education and service staff at all stages of the curriculum process. The model highlights eight key areas for the curriculum team to consider: the curriculum model to be used, sequencing of taught content and clinical practice, the content of the course, teaching methods to be used, assessment criteria, the role of tutors in the learning process, the contribution of service staff, and the influence of the hidden curriculum. It is argued that only through such a comprehensive model can integration of theory and practice within the curriculum be achieved. Adoption of the model, however, will require considerable individual and organizational commitment.

Evaluation of a community staff preparation strategy for the teaching, assessing and mentorship of Project 2000 diploma students.

This article presents findings of a study which investigated effectiveness of an educational strategy for community nurses in relationship to their teaching, assessing and mentorship roles with Project 2000 diploma student nurses. The research was conducted in the North Staffordshire Health District when the College of Nursing and Midwifery's first cohort of Project 2000 diploma students were in their third year of studies. Data were collected using a postal questionnaire and face-to-face interviews. The findings reveal that just over half the sample felt they had adequate preparation for their role of teachers and assessors of Project 2000 diploma students. Analysis of the data showed that there had been a need initially for more information to be disseminated regarding the college curriculum and assessment criteria. Chi square analysis revealed a significant result in relationship to those in the sample who felt they were adequately prepared for their teaching and assessment role and those who had undertaken a formal teaching and assessing course. The findings have implications for the desirability of community nurses to undertake formal teaching and assessing courses. Conclusions can also be drawn regarding future ventures in curriculum innovation and the need for adequate clinical staff preparation for changed needs of a curriculum.