Taste and smell dysfunction in childhood cancer survivors.

INTRODUCTION: Reduced or altered taste and smell function may occur as a side-effect of cancer therapy. This can lead to altered nutrient and energy intake. Some studies have suggested that taste and smell dysfunction can persist many years after treatment completion but this has not been previously assessed in survivors of childhood cancer. The aim of this study is to determine if taste and smell dysfunction is present in childhood cancer survivors (CCS). Food preference and Quality of Life was also assessed. METHODS: Fifty-one child cancer survivors (mean age: 19.69±7.09years), more than five years since treatment completion, (mean: 12.4years) were recruited from the long term follow-up clinics at two Sydney-based children's hospitals. Taste function was assessed using a 25 sample taste identification test comprising five concentrations each of sweet, salty, sour and bitter tastes and water. Smell function was assessed by determining the ability of participants to identify 16 common odorants. The participants' Quality of Life was assessed using the Functional Assessment of Anorexia Cachexia scale and food preferences were assessed using a 94-item food liking tool. RESULTS: Taste dysfunction was found in 27.5% of participants (n=14), and smell dysfunction in 3.9% (n=2) of participants. The prevalence of taste dysfunction was higher than that seen in the non-cancer population. The child cancer survivors' appeared to "like" the less healthy food groups such as flavoured beverages, takeaway and snacks over healthier food groups such as vegetables and salad. No correlation was found between those with a taste dysfunction and their food "likes". CONCLUSION: A high level of taste dysfunction was found in CCS though there did not appear to be an issue with smell dysfunction. Further work is also needed to assess whether a taste dysfunction do play a role in the dietary habits of CCS.

Chemosensory function and food preferences of children with cystic fibrosis.

A major problem for patients with cystic fibrosis (CF) is the maintenance of adequate nutrition to maintain normal growth. The hypotheses that poor nutrition could be due to smell and/or taste dysfunction has been pursued in several studies with contradictory results. None, however, investigated whether inadequate nutrition is due to CF patients having different liking for foods compared to healthy children and whether liking can be linked to specific changes in smell or taste function. Here, the relationships between food liking, BMI, and smell and taste function in 42 CF and 42 healthy 5- to 18-year olds is pursued. A three-choice 16-item odor identification test and a gustatory identification test involving five concentrations of sweet, sour, bitter, and salty tastes, were used to assess chemosensory function. Food liking was assessed using a 94-item questionnaire. Patients identified significantly fewer odors than controls (89.8% vs. 95.7% correct; P < 0.001). However, only a few patients were affected and their loss of olfactory function was not substantial and unlikely to affect their liking for foods. Taste identification was similar for the two groups (patients 92.6% vs. controls 94.2% correct). There was no correlation between age and odor identification ability, but taste performance improved with age (r = 0.39, P < 0.05), suggesting cognition was the cause. Patients liked several types of foods and high-fat foods more than the controls. Both groups had a similar liking for low-fat foods and both liked high-fat foods more than low-fat foods. No significant relationships existed between FEV(1) and smell or taste function or liking for foods, the BMI of the groups were similar and there was no relationship between BMI and smell or taste function. The results indicate that the abnormal eating behavior reported for many CF patients is not due to changes in chemosensory function which remains normal in most CF patients at least to 18 years of age.

Smell and taste function in children with chronic kidney disease.

Loss of appetite and poor growth are common in children with chronic kidney disease (CKD), and changes in smell and/or taste function may be responsible, but the hypothesis has not been proven. This aims of this prospective age- and gender-controlled study were to determine whether: (1) changes in smell and taste function occur in children with CKD; (2) smell or taste dysfunction are associated with estimated glomerular filtration rate (eGFR); (3) there is an association between smell or taste loss and body mass index (BMI). The study cohort consisted of 72 children of whom 20 were CKD stage 3-5 patients, 12 were CKD stage 2 patients, 20 were clinical controls (CC) and 20 were healthy children (HC). The CKD patients and clinical controls were recruited from Sydney Children's Hospital and The Children's Hospital, Westmead, and healthy controls were recruited from a local school. Scores for each group from taste and smell chemosensory function tests were compared, and their relationship with renal function and BMI investigated. The CKD stage 3-5 group had a significantly lower taste identification score (85.6%, P < 0.001) than the CC (94.8%) and HC (94.8%) groups, with almost one third of the children in the CKD stage 3-5 group exhibiting taste loss. Decreased taste function was associated with decreased eGFR (r = 0.43, P < 0.01), but no association between BMI and taste function was found (r = 0.001, P > 0.9). Odour identification scores were not different; however, there was a positive relationship with BMI (r = 0.427, P = 0.006). We conclude that a loss of taste can occur in children with CKD and that when it occurs, it worsens as eGFR declines and is found early in kidney disease.

Temporal processing of olfactory stimuli during retronasal perception.

Odorants can be perceived via the nose during an inhalation or sniff (orthonasal perception) and via the mouth, nasopharynx and nasal cavity during mastication or drinking (retronasal perception). Previous data suggest that orthonasal perception provides a more efficient route with greater difficulty being reported when detecting [Halpern BP. Retronasal and orthonasal smelling. Chemosense 2004;6:1-7; Voirol E, Daget N. Comparative study of nasal and retronasal olfactory perception. Lebensmittel-Wissenschaft Technol 1986;19:316-9] and identifying [Heilmann S, Hummel T. A new method for comparing orthonasal and retronasal olfaction. Behav Neurosci 2004;118:412-9; Sun BC, Halpern BP. Identification of air-phase retronasal and orthonasal odorant pairs. Chem Senses 2005;30:1-14] single odorants retronasally. Whether the poorer sensitivity obtained via the retronasal route is largely due to the greater adsorption of odorants by the nasopharyngeal mucus compared to the nasal mucus thereby reducing their peak concentration and/or slowing their passage, has not been resolved. Importantly, the question of whether solubility of odorants in mucus or water predicts the outcomes for perception of stimuli presented via the retronasal route has not been resolved. Accordingly, the present study investigates this question by determining whether the solubility of an odorant in mucus predicts which component of a binary odour mixture is perceived first during retronasal perception. The results indicate that solubility in mucus rather than solubility in water is a better predictor of which odour will be perceived first and identified more readily during the retronasal perception of a binary mixture. In addition, lower intensity levels of single odorants occurred via the retronasal route suggesting that adsorption was greater via this route. Whether this was due to nasopharyngeal mucus having a greater adsorptive area or different composition compared to the orthonasal pathway is not known.

Olfactory function in Australian aboriginal children and chronic otitis media.

Chronic suppurative otitis media (CSOM), a severe form of middle ear infection, affects most Australian Aboriginal children with up to 50% in some communities suffering hearing loss as a consequence. To date, there is no information on whether repeated exposure to the pathogens that characterize CSOM and that are present in the upper respiratory airway affect olfactory function. Accordingly, this study aimed to determine whether 1) there was a high prevalence of olfactory loss in Aboriginal children and 2) hearing loss is a predictor of olfactory loss. Two hundred and sixty one 9- to 12-year-old Aboriginal children from 16 rural communities reported to have high prevalences of CSOM and hearing loss were assessed for olfactory loss using a 16-odor identification test and hearing loss. One child was found to be anosmic, 4 were slightly hyposmic, and 42 had hearing loss. No relationship was found between olfactory loss and hearing loss. The test-retest reliability of the 16-odor identification test was 0.98. It was concluded that CSOM does not appear to affect olfactory function in the long term and that hearing loss in Aboriginal children is not a predictor of olfactory loss.