University of Southern California
Mrs. T.H. Chan Division of Occupational Science and Occupational Therapy
Redesigning Lives Globally
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Derek Snyder PhD

Derek Snyder

Research Assistant Professor

Room: CHP 133
Phone: (323) 442-2326
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Research Assistant Professor Derek Snyder is an expert on the physiology and perception of flavor sensation in animal and human populations. His publications have appeared in Physiology & Behavior, Chemical Senses and Advances in Oto-Rhino-Laryngology. He was a former chair of the American Psychological Association of Graduate Students.


Journal Articles

Kalva, J. J., Sims, C. A., Puentes, L. A., Snyder, D. J., & Bartoshuk, L. M. (2014). Comparison of the hedonic general Labeled Magnitude Scale with the hedonic 9-point scale. Journal of Food Science, 79, S238-S245. doi:10.1111/1750-3841.12342. Link to full text Abstract →← Abstract 

The hedonic 9-point scale was designed to compare palatability among different food items; however, it has also been used occasionally to compare individuals and groups. Such comparisons can be invalid because scale labels (for example, "like extremely") can denote systematically different hedonic intensities across some groups. Addressing this problem, the hedonic general Labeled Magnitude Scale (gLMS) frames affective experience in terms of the strongest imaginable liking/disliking of any kind, which can yield valid group comparisons of food palatability provided extreme hedonic experiences are unrelated to food. For each scale, 200 panelists rated affect for remembered food products (including favorite and least favorite foods) and sampled foods; they also sampled taste stimuli (quinine, sucrose, NaCl, citric acid) and rated their intensity. Finally, subjects identified experiences representing the endpoints of the hedonic gLMS. Both scales were similar in their ability to detect within-subject hedonic differences across a range of food experiences, but group comparisons favored the hedonic gLMS. With the 9-point scale, extreme labels were strongly associated with extremes in food affect. In contrast, gLMS data showed that scale extremes referenced nonfood experiences. Perceived taste intensity significantly influenced differences in food liking/disliking (for example, those experiencing the most intense tastes, called supertasters, showed more extreme liking and disliking for their favorite and least favorite foods). Scales like the hedonic gLMS are suitable for across-group comparisons of food palatability.

Fischer, M. E., Cruickshanks, K. J., Schubert, C. R., Pinto, A., Klein, B. E., Klein, R., Nieto, F. J., Pankow, J. S., Huang, G. H., & Snyder, D. J. (2013). Taste intensity in the Beaver Dam Offspring Study. The Laryngoscope, 123, 1399-1404. doi:10.1002/lary.23894. Link to full text Abstract →← Abstract 

OBJECTIVES/HYPOTHESIS: To determine the distribution of the perceived intensity of salt, sweet, sour, and bitter in a large population and to investigate factors associated with perceived taste intensity.
STUDY DESIGN: Cross-sectional population.
METHODS: Subjects (n = 2,374; mean age, 48.8 years) were participants in the Beaver Dam Offspring Study examined during 2005 to 2008. Perceived taste intensity was measured using paper disks and a general labeled magnitude scale. Multiple linear regression was performed.
RESULTS: Mean intensity ratings were: salt = 27.2 (standard deviation [SD] = 18.5), sweet = 20.4 (SD = 15.0), sour = 35.7 (SD = 21.4), and bitter = 49.6 (SD = 23.3). Females and those with less than a college degree education rated tastes stronger. With adjustment for age, sex, and education, stronger perceived sour and bitter intensities were related to current smoking (sour: B = 2.8, 95% confidence interval [CI], 0.4 to 5.2; bitter: B = 2.8, 95% CI, 0.3 to 5.4) and lipid-lowering medications (sour: B = 5.1, 95% CI, 2.5 to 7.6; bitter: B = 3.2, 95% CI, 0.6 to 5.8). Alcohol consumption in the past year was related to weaker salt (B = -2.8, 95% CI, -5.3 to -0.3) and sweet intensity ratings (B = -2.3, 95% CI, -4.3 to -0.3), whereas olfactory impairment was associated with higher sweet ratings (B = 4.7, 95% CI, 1.4 to 7.9).
CONCLUSIONS: Perceived intensities were strongest for bitter and weakest for sweet. Sex and education were associated with each taste, whereas age did not demonstrate a consistent relationship. Associations with other factors differed by tastants, with current smoking and alcohol consumption being related to some tastes.

Tieman, D., Bliss, P., McIntyre, L. M., Blandon-Ubeda, A., Bies, D., Odabasi, A. Z., Rodríguez, G. R., van der Knaap, E., Taylor, M. G., Goulet, C., Mageroy, M. H., Snyder, D. J., Colquhoun, T., Moskowitz, H., Clark, D. G., Sims, C., Bartoshuk, L., & Klee, H. J. (2012). The chemical interactions underlying tomato flavor preferences. Current Biology, 22, 1035-1039. doi:10.1016/j.cub.2012.04.016. Link to full text Abstract →← Abstract 

Although human perception of food flavors involves integration of multiple sensory inputs, the most salient sensations are taste and olfaction. Ortho- and retronasal olfaction are particularly crucial to flavor because they provide the qualitative diversity so important to identify safe versus dangerous foods. Historically, flavor research has prioritized aroma volatiles present at levels exceeding the orthonasally measured odor threshold, ignoring the variation in the rate at which odor intensities grow above threshold. Furthermore, the chemical composition of a food in itself tells us very little about whether or not that food will be liked. Clearly, alternative approaches are needed to elucidate flavor chemistry. Here we use targeted metabolomics and natural variation in flavor-associated sugars, acids, and aroma volatiles to evaluate the chemistry of tomato fruits, creating a predictive and testable model of liking. This nontraditional approach provides novel insights into flavor chemistry, the interactions between taste and retronasal olfaction, and a paradigm for enhancing liking of natural products. Some of the most abundant volatiles do not contribute to consumer liking, whereas other less abundant ones do. Aroma volatiles make contributions to perceived sweetness independent of sugar concentration, suggesting a novel way to increase perception of sweetness without adding sugar.

Fischer, M. E., Cruickshanks, K. J., Pinto, A., Schubert, C. R., Klein, B. E., Klein, R., Nieto, F. J., Pankow, J. S., Snyder, D. J., & Keating, B. J. (2012). Intensity of salt taste and prevalence of hypertension are not related in the Beaver Dam Offspring Study. Chemosensory perception, 5, 139-145. doi:10.1007/s12078-012-9118-8. Link to full text Abstract →← Abstract 

BACKGROUND: Standard clinical advice for the prevention and treatment of hypertension includes limitation of salt intake. Previous studies of the association between perception of salt taste and hypertension prevalence have not reported consistent results and have usually been conducted in small study populations.
PURPOSE: To determine the cross-sectional relationship between intensity of salt taste, discretionary salt use, and hypertension.
METHODS: Subjects (n=2371, mean age=48.8 years) were participants in the Beaver Dam Offspring Study (BOSS), an investigation of sensory loss and aging conducted in 2005-2008. Salt taste intensity was measured using a filter paper disk impregnated with 1.0 M sodium chloride and a general Labeled Magnitude Scale (gLMS). Hypertension was defined as systolic blood pressure ≥ 140 mmHg or diastolic blood pressure ≥ 90 mmHg, or use of high blood pressure medication.
RESULTS: Nearly 32% of the participants rated the salt disk as weak or having no taste while approximately 10% considered it to be very strong or stronger. The intensity was reported to be less strong by males (P < 0.001) and college graduates (P = 0.02) and was inversely associated with frequency of adding salt to foods (P = 0.02). There was no significant association between hypertension and the intensity of salt taste, before and after adjustment for covariates. Exclusion of subjects with a history of physician diagnosed hypertension did not appreciably alter these findings.
CONCLUSIONS: The perception of salt taste was related to the frequency of discretionary salt use but not to hypertension status or mean blood pressure.

Bartoshuk, L. M., Catalanotto, F., Hoffman, H., Logan, H., & Snyder, D. J. (2012). Taste damage (otitis media, tonsillectomy and head and neck cancer), oral sensations and BMI. Physiology & Behavior, 107, 516-526. doi:10.1016/j.physbeh.2012.06.013. Link to full text Abstract →← Abstract 

Otitis media and tonsillectomy are associated with enhanced palatability of energy dense foods and with weight gain. Otitis media can damage the chorda tympani nerve (CN VII); tonsillectomy and head and neck radiation treatment can damage the glossopharyngeal nerve (CN IX). Both of these nerves function prominently in taste sensation. The present study utilizes these sources of damage to study central interactions among the nerves that mediate oral sensations. Mild damage restricted to one of these nerves can actually intensify sensations evoked from undamaged nerves (i.e., whole-mouth taste, oral tactile sensations evoked by fats and irritants). These intensifications may result from disruption of central inhibitory taste circuits, as taste damage appears to disinhibit other oral sensory nerves. In addition, mild damage restricted to one taste nerve can intensify odors perceived from foods in the mouth during chewing and swallowing (i.e., retronasal olfaction); this may be a secondary consequence of the intensification of whole-mouth taste. Damage to both nerves leads to widespread oral sensory loss. At present, the link between sensory alterations and weight gain has not been established for adults (e.g., does increased fat preference occur in individuals with oral sensory intensifications, those with losses, or both?). Finally, pain in non-oral locations is also related to taste loss. When participants rated "the most intense pain of any kind they had ever experienced," those with the greatest taste loss gave the highest ratings. These effects suggest that taste loss significantly influences long-term health outcomes.

Snyder, D. J., & Bartoshuk, L. M. (2009). Epidemiological studies of taste function: Discussion and perspectives. Annals of the New York Academy of Sciences, 1170, 574-580. doi:10.1111/j.1749-6632.2009.04487.x. Link to full text Abstract →← Abstract 

Efforts to quantify the public health impact of chemosensation present significant challenges, including a strong need for testing methods suitable for field assessment. This discussion highlights several promising approaches to the population-based study of taste function; it also identifies key principles that should be considered when adapting laboratory-based taste tests for field use.

Cruickshanks, K. J., Schubert, C. R., Snyder, D. J., Bartoshuk, L. M., Huang, G. H., Klein, B. E., Klein, R., Nieto, F. J., Pankow, J. S., Tweed, T. S., Krantz, E. M., & Moy, G. S. (2009). Measuring taste impairment in epidemiologic studies: The Beaver Dam Offspring Study. Annals of the New York Academy of Sciences, 1170, 543-552. doi:10.1111/j.1749-6632.2009.04103.x. Link to full text Abstract →← Abstract 

Taste or gustatory function may play an important role in determining diet and nutritional status and therefore indirectly impact health. Yet there have been few attempts to study the spectrum of taste function and dysfunction in human populations. Epidemiologic studies are needed to understand the impact of taste function and dysfunction on public health, to identify modifiable risk factors, and to develop and test strategies to prevent clinically significant dysfunction. However, measuring taste function in epidemiologic studies is challenging and requires repeatable, efficient methods that can measure change over time. Insights gained from translating laboratory-based methods to a population-based study, the Beaver Dam Offspring Study (BOSS) will be shared. In this study, a generalized labeled magnitude scale (gLMS) method was used to measure taste intensity of filter paper disks saturated with salt, sucrose, citric acid, quinine, or 6-n-propylthiouracil, and a gLMS measure of taste preferences was administered. In addition, a portable, inexpensive camera system to capture digital images of fungiform papillae and a masked grading system to measure the density of fungiform papillae were developed. Adult children of participants in the population-based Epidemiology of Hearing Loss Study in Beaver Dam, Wisconsin, are eligible for this ongoing study. The parents were residents of Beaver Dam and 43-84 years of age in 1987-1988; offspring ranged in age from 21-84 years in 2005-2008. Methods will be described in detail and preliminary results about the distributions of taste function in the BOSS cohort will be presented.

Bartoshuk, L. M., Duffy, V. B., Hayes, J. E., Moskowitz, H. R., & Snyder, D. J. (2006). Psychophysics of sweet and fat perception in obesity: Problems, solutions and new perspectives. Philsophical Transactions of The Royal Society: Series B, Biological Sciences, 361, 1137-1148. doi:10.1098/rstb.2006.1853. Link to full text Abstract →← Abstract 

Psychophysical comparisons seem to show that obese individuals experience normal sweet and fat sensations, they like sweetness the same or less, but like fat more than the non-obese do. These psychophysical comparisons have been made using scales (visual analogue or category) that assume intensity labels (e.g. extremely) which denote the same absolute perceived intensity to all. In reality, the perceived intensities denoted by labels vary because they depend on experiences with the substances to be judged. This variation makes comparisons invalid. Valid comparisons can be made by asking the subjects to rate their sensory/hedonic experiences in contexts that are not related to the specific experiences of interest. Using this methodology, we present the evidence that the sensory and hedonic properties of sweet and fat vary with body mass index. The obese live in different orosensory and orohedonic worlds than do the non-obese; the obese experience reduced sweetness, which probably intensifies fat sensations, and the obese like both sweet and fat more than the non-obese do. Genetic variation as well as taste pathology contribute to these results. These psychophysical advances will impact experimental as well as clinical studies of obesity and other eating disorders.

Snyder, D. J., Prescott, J., & Bartoshuk, L. M. (2006). Modern psychophysics and the assessment of human oral sensation. Advances in Oto-Rhino-Laryngology, 63, 221-241. Link to full text Abstract →← Abstract 

Psychophysical measures attempt to capture and compare subjective experiences objectively. In the chemical senses, these techniques have been instrumental in describing relationships between oral sensation and health risk, but they are often used incorrectly to make group comparisons. This chapter reviews contemporary methods of oral sensory assessment, with particular emphasis on suprathreshold scaling. We believe that these scales presently offer the most realistic picture of oral sensory function, but only when they are used correctly. Using converging methods from psychophysics, anatomy, and genetics, we demonstrate valid uses of modern chemosensory testing in clinical diagnosis and intervention.

Bartoshuk, L. M., Snyder, D. J., Grushka, M., Berger, A. M., Duffy, V. B., & Kveton, J. F. (2005). Taste damage: Previously unsuspected consequences. Chemical Senses, 30, i218-i219. doi:10.1093/chemse/bjh192. Link to full text

Bartoshuk, L. M., Duffy, V. B., Green, B. G., Hoffman, H. J., Ko, C. W., Lucchina, L. A., Marks, L. E., Snyder, D. J., & Weiffenbach, J. M. (2004). Valid across-group comparisons with labeled scales: The gLMS versus magnitude matching. Physiology & Behavior, 82, 109-114. doi:10.1016/j.physbeh.2004.02.033. Link to full text Abstract →← Abstract 

Labeled scales are commonly used for across-group comparisons. The labels consist of adjective/adverb intensity descriptors (e.g., "very strong"). The relative distances among descriptors are essentially constant but the absolute perceived intensities they denote vary with the domain to which they are applied (e.g., a "very strong" rose odor is weaker than a "very strong" headache), as if descriptors were printed on an elastic ruler that compresses or expands to fit the domain of interest. Variation in individual experience also causes the elastic ruler to compress or expand. Taste varies genetically: supertasters perceive the most intense tastes; nontasters, the weakest; and medium tasters, intermediate tastes. Taste intensity descriptors on conventional-labeled scales denote different absolute perceived intensities to the three groups making comparisons across the groups invalid. Magnitude matching provides valid comparisons by asking subjects to express tastes relative to a standard not related to taste (e.g., supertasters match tastes to louder sounds than do nontasters). Borrowing the logic of magnitude matching, we constructed a labeled scale using descriptors unrelated to taste. We reasoned that expressing tastes on a scale labeled in terms of all sensory experience might work. We generalized an existing scale, the Labeled Magnitude Scale (LMS), by placing the label "strongest imaginable sensation of any kind" at the top. One hundred subjects rated tastes and tones using the generalized LMS (gLMS) and magnitude matching. The two methods produced similar results suggesting that the gLMS is valid for taste comparisons across nontasters, medium tasters, and supertasters.

Duffy, V. B., Davidson, A. C., Kidd, J. R., Kidd, K. K., Speed, W. C., Pakstis, A. J., Reed, D. R., Snyder, D. J., & Bartoshuk, L. M. (2004). Bitter receptor gene (TAS2R38), 6-n-propylthiouracil (PROP) bitterness and alcohol intake. Alcoholism: Clinical & Experimental Research, 28, 1629-1637. doi:10.1097/01.ALC.0000145789.55183.D4. Link to full text Abstract →← Abstract 

BACKGROUND: Phenylthiocarbamide (PTC) and 6-n-propylthiouracil (PROP), chemically related compounds, are probes for genetic variation in bitter taste, although PROP is safer with less sulfurous odor. Threshold for PROP distinguishes nontasters (increased threshold) from tasters (lower threshold); perceived intensity subdivides tasters into medium tasters (PROP is bitter) and supertasters (PROP is very bitter). Compared with supertasters, nontasters have fewer taste papillae on the anterior tongue (fungiform papillae) and experience less negative (e.g., bitterness) and more positive (eg, sweetness) sensations from alcohol. We determined whether the TAS2R38 gene at 7q36 predicted PROP bitterness, alcohol sensation and use.
METHODS: Healthy adults (53 women, 31 men; mean age 36 years)--primarily light and moderate drinkers--reported the bitterness of five PROP concentrations (0.032-3.2 mM) and intensity of 50% ethanol on the general Labeled Magnitude Scale. PROP threshold and density of fungiform papillae were also measured. Subjects had common TAS2R38 gene haplotypes [alanine-valine-isoleucine (AVI) and proline-alanine-valine (PAV)].
RESULTS: PROP bitterness varied significantly across genotypes with repeated measures ANOVA: 26 AVI/AVI homozygotes tasted less bitterness than either 37 PAV/AVI heterozygotes or 21 PAV/PAV homozygotes. The PAV/PAV group exceeded the PAV/AVI group for bitterness only for the top PROP concentrations. The elevated bitterness was musch less than if we defined the groups using psychophysical criteria. With multiple regression analyses, greater bitterness from 3.2 mM PROP was a significant predictor of greater ethanol intensity and less alcohol intake--effects separate from age and sex. Genotype was a significant predictor of alcohol intake, but not ethanol intensity. With ANOVA, AVI/AVI homozygotes reported higher alcohol use than either PAV/AVI heterozygotes or PAV/PAV homozygotes. When age effects were minimized, PROP bitterness explained more variance in alcohol intake than did the TAS2R38 genotype.
CONCLUSIONS: These results support taste genetic effects on alcohol intake. PROP bitterness serves as a marker of these effects.

Snyder, D. J., Jahng, J. W., Smith, J. C., & Houpt, T. A. (2000). c-Fos induction in visceral and vestibular nuclei of the rat brain stem by a 9.4 T magnetic field. NeuroReport, 11, 2681-2685. Link to full text Abstract →← Abstract 

Recently, it has been shown that rats placed in a 9.4T static magnetic field for 30 min after drinking a glucose-saccharin solution develop a conditioned taste aversion (CTA) to glucose-saccharin. We sought to identify brain stem regions that are activated by the 9.4 T magnetic field exposure using c-Fos immunohistochemistry. Rats were restrained in a 9.4 T magnet for 30 min; sham-exposed rats were restrained but not exposed to the magnetic field. The magnetic field induced significantly more c-Fos-positive cells than sham treatment in the solitary tract, parabrachial, medial vestibular, prepositus, and supragenualis nuclei. These results suggest that magnetic field exposure causes neural activation in visceral and vestibular nuclei that may promote CTA learning.

Prutkin, J., Fisher, E. M., Etter, L., Fast, K., Gardner, E., Lucchina, L. A., Snyder, D. J., Tie, K., Weiffenbach, J., & Bartoshuk, L. M. (2000). Genetic variation and inferences about perceived taste intensity in mice and men. Physiology & Behavior, 69, 161-173. doi:10.1016/S0031-9384(00)00199-2. Link to full text Abstract →← Abstract 

The study of genetic variation in taste produces parallels between mice and men. In mice, genetic variation across strains has been documented with psychophysical and anatomical measures as well as with recordings from whole nerves. In humans, the variation has been documented with psychophysical and anatomical measures. Whole-nerve recordings from animals and psychophysical ratings of perceived intensities from human subjects have a similar logical limitation: absolute comparisons across individuals require a standard stimulus that can be assumed equally intense to all. Comparisons across whole-nerve recordings are aided by single-fiber recordings. Comparisons across psychophysical ratings of perceived intensity have been aided by recent advances in methodology; these advances now reveal that the magnitude of genetic variation in human subjects is larger than previously suspected. In females, hormones further contribute to variation in taste. There is evidence that the ability to taste (particularly bitter) cycles with hormones in women of child-bearing age, rises to a maximum early in pregnancy and declines after menopause. Taste affects food preferences, which in turn affect dietary behavior and thus disease risks. Valid assessment of taste variation now permits measurement of the impact of taste variation on health. Advances in psychophysical methodology were essential to understanding genetic variation in taste. In turn, the association of perceived taste intensities with tongue anatomy now provides a new tool for psychophysics. The ability of a psychophysical scale to provide across-subject comparisons can be assessed through its ability to show the fungiform papillae density-taste association.