Biomedical subjects
Publications and source records attributed to W S Cain.
Successful odor identification depends on (i) commonly encountered substances, (ii) a long-standing connection between an odor and its name, and (iii) aid in recalling the name. The absence of any one ingredient impairs performance dramatically, but the presence of all three permits ready identification of scores of substances, with performance seemingly limited only by the inherent confusability of the stimuli.
Thirteen children with localized (Evans stage I or II) thoracic primary neuroblastoma were divided into two groups according to the type of therapy administered, in order to compare the therapeutic efficacy and morbidity of excisional surgery followed by either irradiation alone or irradiation plus chemotherapy (group A) with similar surgery alone (group B). Group A consisted of 6 children (mean age 1 year, 2 months). Complete surgical excision was accomplished in 2 patients, while 4 had microscopic residual. All 6 patients are free of disease at 26--76 months (mean 47 months), including 2 who had recurrent tumor and received additional therapy. Two have developed congestive heart failure and one severe scoliosis secondary to irradiation. Of the 7 children in group B (mean age 2 years, 2 months), 3 had microscopic residual tumor and 2 had adjacent lymph node involvement. After 12--47 months (mean 23 months), no recurrence or surgery-related morbidity has been observed. From these limited data it appears that surgery alone may provide adequate therapy for localized thoracic neuroblastoma and obviate the morbidity associated with multimodal therapy.
Neurology manuals generally recommend odor identification for simple assessment of olfaction. Nevertheless, even patients with normal olfaction (normosmics) often perform only poorly. Three experiments demonstrate that such an ambiguous outcome will disappear if the test incorporates highly familiar substances and, more important, a procedure to circumvent the olfactory-verbal gap that frequently separates an odor from its name. One multiple-choice procedure, for instance, led to 100% accuracy among normosmics. Another led to 99% accuracy among normosmics and 0% accuracy among anosmics. The investigation also reveals that scratch-and-sniff labels could possibly replace customary odorants in the clinical test.
Subjects judged the pleasantness of various odorants both before and after intensive exposure to a pleasant, a neutral, or an unpleasant odorant, or a short period of relaxation. Intensive exposure comprised a 30 min task of intensity discrimination. The outcome implied that exposure to an odorant can modify its own pleasantness readily, but not so readily that of other odorants. Exposure to the pleasant lemon-smelling substance citral reduced its subsequent pleasantness, whereas exposure to the unpleasant rancid-smelling substance isobutyric acid reduced its subsequent unpleasantness. The results were compatible with the notion of affective habituation. Variability of the pleasantness judgments was uniform throughout the hedonic continuum. That is, subjects agreed as much about hedonically neutral odors as about extremely pleasant and unpleasant odors.
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The ability of subjects to resolve differences in concentration of chemicals in the vapor phase by smell rivaled the optimum performance of chromatographs. In some instances, subjects resolved a difference in concentration of only 5 percent. The reported inability of olfaction to register fine differences in intensity seems to be largely a result of fluctuations in the stimulus.
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Subjects estimated the intensity of various concentrations of an odorant (ethyl butyrate), a tastant (sodium saccharin), and mixtures of the two. The question of primary interest was whether the perceived intensity of the odor-tast mixtures would be equal to, greater than , or less than the intensities of the unmixed components. The outcome approximated simple additivity: The intensity of the mixtures was only slightly less than the sum of the perceived intensities of the unmixed components. An examination of how subjects apportioned their judgments into the categories odor and taste revealed the existence of taste-smell confusions. Subjects ascribed little odor magnitude to solutions containing only sodium saccharin, but ascribed considerable taste magnitude to solutions containing only ethyl butyrate. The taste ascribed to ethyl butyrate was not due exclusively to its action on gustation since, when the nostrils were closed, as much as 80% of the "taste" disappeared. Subjects seem to resolve ambiguity regarding the locus of mutual olfactory-taste stimulation in favor of taste.
Three experiments explored the olfactory and the common chemical attributes of sensations produced by various concentrations of n-butyl alcohol. These two attributes combine in an almost-linear fashion to produce the overall perceived intensity of the stimulus. Common chemical intensity makes only a small contribution to overall magnitude at low concentrations, but its proportional contribution increases with concentration. In like manner, speed of response (i.e., reciprocal of reaction time) to the common chemical attribute increases more rapidly than that to odor. Nevertheless, odor always makes its appearance sooner than the common chemical attribute, even when the two attributes are matched in perceived magnitude. Repeated inhalations cause odor intensity to decrease slightly but cause common chemical intensity to increase dramatically. The results obtained from the normal subjects studied here agree with those obtained from subjects with unilateral destruction of the trigeminal nerve.
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Psychophysical experiments measured both olfactory sensitivity to 1-butanol and sodium chloride and taste sensitivity to sodium chloride in normal children and in children with cystic fibrosis. The sensitivity of the children with cystic fibrosis fell within the normal range. These results stand in contrast to those of Henkin and Powell, who found children with cystic fibrosis to be hypersensitive to both olfactory and taste stimuli. Apparent hypersensitivity to taste stimuli could have resulted from the adapting effects of the relatively high level of sodium in the saliva of children with cystic fibrosis. If the contaminating effects of saliva are removed, children with cystic fibrosis yield, on the average, a taste threshold identical to that of normal children. There appears to be no simple explanation for why Henkin and Powell found hypersensitivity to odorants. The present results indicate that, in fact, children with cystic fibrosis display a slight hyposensitivity to odorants.
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