Olfactory performance during childhood. II. Developing a discrimination task for children

Olfactory Dysfunction in Children: A Scoping Review

OBJECTIVE

Olfactory disorders are well-studied in the adult population, however, there is a paucity of literature characterizing olfactory dysfunction in pediatric patients. The purpose of this scoping review was to identify known causes of olfactory loss in pediatric populations, clarify the extent of use and validity of smell tests, and summarize current therapies for olfactory loss.

DATA SOURCES

PubMed, Ovid MEDLINE, and Web of Science.

REVIEW METHODS

Databases were systematically searched in September 2020. Two independent reviewers conducted the title and abstract screen, followed by review of full-texts for inclusion based on preset inclusion and exclusion criteria. Extracted data included study type, age/age-range of participants, gender, radiological evidence of olfactory dysfunction, types and results of smell tests used, etiology of olfactory loss, and therapies employed for olfactory loss.

RESULTS

A total of 103 articles (n = 1654) were eligible for final data extraction. The University of Pennsylvania Smell Identification Test was used most frequently for smell testing (21% of studies). In total, 45 causes of olfactory dysfunction have been elucidated by this study: 22 congenital and 23 acquired. Few therapies were described, and all were specific to the etiology of olfactory loss.

CONCLUSION

Olfactory dysfunction has a wide range of etiologies in the pediatric population, and clinicians should have a diagnostic algorithm for how to identify a cause should they encounter it in practice. If no etiology can be identified, education around safety should be provided to both the patient and their caregivers.

Olfactory disorders in childhood: A comparative study of olfaction in children with adenoid hyperplasia versus a control group and the postoperative effects of adenoidectomy with respect to olfactory ability

PURPOSE

Hyposmia in childhood is poorly characterized. The "U-Sniff Test", validated for children with anosmia, can be used to objectify olfactory impairment but has not been used to distinguish between hyposmia and normosmia. Therefore, we investigated children with enlarged adenoids with respect to hyposmia, its correlation with adenoid size, and the sensitivity of questionnaires to predict olfactory impairment.

METHODS

In a prospective comparison, olfaction was assessed by "U-Sniff Test" (score 0-12; <8 hyposmia) in 41 children (5-18 years) with adenoid hyperplasia and compared with 196 children without any respiratory affection (control) after exclusion of previous SARS-Cov2-infection from December 2020 to December 2021. ENT-related complaints were collected using a self-designed questionnaire. We were able to include 13 children in a follow-up examination to compare preoperative performance in the "U-Sniff Test" with postoperative outcome after adenoidectomy.

STATISTICS

chi-square-test (p < 0.05), odds-ratio, Spearman's rho, ROC-, cluster analysis.

RESULTS

Severe hyposmia was present in 36.6% of children with adenoid-hyperplasia compared to 3.1% of the control-group. Adenoid-children scored significantly more often between 8 and 10 points (58.5%) than the control (31.6%; p < 0.01). Adenoid size and olfactory performance correlate significantly (r: 0.83; CI -0.89 … -0.72). Hyposmia in the adenoid group is characterized predominately by loss of the odors banana, butter and rose. None of children with hyposmia or parents reported impaired olfactory performance. Postoperatively, olfactory function improved significantly in 85% of cases (p 0.01, SD ± 1.71, Δ3.54points).

CONCLUSION

Questionnaires are insufficient to detect hyposmia in this cohort. In contrast, the "U-Sniff Test" detects even reduced olfactory performance without reaching the cut-off value, which represents the majority of test results in the adenoid group. Therefore, we recommend the classification of moderate hyposmia (8-10 points) to be included for our study population.

Smell and Taste Dysfunction in Pediatric Patients With SARS-CoV-2 Infection

INTRODUCTION

Anosmia and hypogeusia are frequent symptoms in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in adults, but their incidence in children is unknown.

OBJECTIVE

Describe the incidence and associated characteristics of olfactory and gustatory dysfunction in children with SARS-CoV-2 infection.

MATERIAL AND METHODS

Descriptive study carried out by telephone survey of patients aged between five and 18 years with SARS-CoV-2 infection confirmed between March and December, 2020.

RESULTS

Two hundred eighty Spanish patients (female: 42.2%) with a mean age of 10.4 years (±3.54, range: 5 to 17) were analyzed, 22.5% with other diseases (mostly respiratory: 11.8%). The most frequent symptoms were fever (55.36%) and neurological symptoms (45.7%). Forty-four (15.7%) were hospitalized due to the infection, in intensive care unit (ICU): 7.1%. Forty-five patients (16.1%) had anosmia and/or hypogeusia: 32 both, eight with hypogeusia only, and five with exclusively anosmia. The mean symptom duration in days for anosmia was 36.4, and for hypogeusia it was 27.6. Either symptom was the initial manifestation in 15 patients. None had anosmia/hypogeusia with no other symptoms. Anosmia/hypogeusia was related to the presence of respiratory infection, gastroenteritis, chills, odynophagia, myalgia, asthenia, and anorexia, but not severity (hospitalization/ICU admission). Cohabitation with another infected individual was associated with a higher incidence of anosmia/hypogeusia (P = 0.041) and duration of anosmia (P = 0.006). The presence of anosmia/hypogeusia in cohabitants was associated with longer duration of anosmia (P < 0.001).

CONCLUSIONS

The incidence of anosmia/hypogeusia in children with SARS-CoV-2 was lower than that reported in adults, although with a longer duration. Although no association was found between anosmia/hypogeusia and greater disease severity, recognition of these symptoms could help identify paucisymptomatic patients.

International consensus statement on allergy and rhinology: Olfaction

BACKGROUND

The literature regarding clinical olfaction, olfactory loss, and olfactory dysfunction has expanded rapidly over the past two decades, with an exponential rise in the past year. There is substantial variability in the quality of this literature and a need to consolidate and critically review the evidence. It is with that aim that we have gathered experts from around the world to produce this International Consensus on Allergy and Rhinology: Olfaction (ICAR:O).

METHODS

Using previously described methodology, specific topics were developed relating to olfaction. Each topic was assigned a literature review, evidence-based review, or evidence-based review with recommendations format as dictated by available evidence and scope within the ICAR:O document. Following iterative reviews of each topic, the ICAR:O document was integrated and reviewed by all authors for final consensus.

RESULTS

The ICAR:O document reviews nearly 100 separate topics within the realm of olfaction, including diagnosis, epidemiology, disease burden, diagnosis, testing, etiology, treatment, and associated pathologies.

CONCLUSION

This critical review of the existing clinical olfaction literature provides much needed insight and clarity into the evaluation, diagnosis, and treatment of patients with olfactory dysfunction, while also clearly delineating gaps in our knowledge and evidence base that we should investigate further.

Assessment of Olfactory Function in Children and Adolescents: An Overview

Valid and reliable tools for assessing olfactory function are necessary for the diagnosis of olfactory dysfunction. Olfactory testing can be challenging in a pediatric population due to shorter attention span, linguistic development, and lower olfactory experience in this age group. The aim of this article is to present an overview about olfactory tests that are suitable for a pediatric population. Publications were included when reporting new developed methods of psychophysical olfactory testing in children or adaptation and applications of existing olfactory tests for a pediatric population. Olfactory tests for all 3 major aspects of olfactory function-olfactory threshold, odor discrimination, and odor identification-were included. Olfactory tests were evaluated regarding test validity, test reliability, normative data, and test availability. The current literature shows that several tests are available to assess olfactory function in children. Especially odor identification abilities in a pediatric population are well examined and understood. Tests for olfactory threshold and odor discrimination are less frequently used. In terms of the abovementioned evaluation criteria, only a few tests met all or 3 of these 4 criteria. Based on the current literature the following tests can be recommended for valid and reliable olfactory testing in children: "U-Sniff" odor identification test, the "Sniffin' Sticks" olfactory threshold test, pBOT-6 olfactory threshold and odor identification test, NIH-Toolbox, and Smell Wheel. Age has to be considered when evaluating olfactory function in children.

Clinical Implications of Psychophysical Olfactory Testing: Assessment, Diagnosis, and Treatment Outcome

Purpose of Review

Olfactory dysfunction dramatically impairs quality of life with a prevalence of 20% in the general adult population. Psychophysical olfactory testing has been widely used to evaluate the ability to smell due to its validated utility and feasibility in clinic. This review summarizes the current literature regarding psychophysical olfactory testing and the clinical relevance of the olfactory testing with different components. Furthermore, the review highlights the diagnosis and treatment value of olfactory subtests in patients with olfactory dysfunction.

Recent Findings

With the accumulation of studies of psychophysical olfactory testing in olfactory disorders, the clinical relevance of olfactory testing with different components is expanding. Different olfactory domains present with distinct olfactory processing and cortical activity. Psychophysical assessment of olfaction with three domains reveals different levels of olfactory processing and might assist with analyzing the pathophysiologic mechanism of the various olfactory disorders. Furthermore, olfactory thresholds provided the largest amount of non-redundant information to the olfactory diagnosis. Sinonasal olfactory dysfunction and non-sinonasal-related olfactory dysfunction are emerging classifications of smell disorders with certain characteristics of olfactory impairment and different responses to the therapy including steroids, sinus surgery, and olfactory training.

Summary

These recent advancements should promote the understanding of psychophysical olfactory testing, the association between individual subcomponents and neurophysiological processes, and pave the way for precision assessment and treatment of the olfactory dysfunction.

Odor identification performance in children aged 3-6 years

BACKGROUND

While valid and reliable olfactory tests have been developed for children aged >5 years, olfactory testing has not systematically been evaluated in younger children. The aim of this study was to evaluate the reliability and validity of the "U-Sniff" odor identification test in children aged 3-6 years.

METHODS

We included 160 healthy children (age range 3-6 years) and 14 congenitally anosmic children. Participants were investigated in two identical sessions. The "U-Sniff" test was used to evaluate olfactory function. A picture identification test (PIT) and the Kasel-Concentration-Task (KKA) were administered to identify factors influencing odor identification performance.

RESULTS

Age significantly influenced odor identification performance, with older children achieving higher scores. PIT and KKA scores correlated positively with odor identification scores. The "U-Sniff" test demonstrated a high test-retest reliability (r₁₆₀ = 0.75, p < 0.001). It was possible to distinguish between healthy and anosmic children by means of "U-Sniff" scores starting at age 4 years with high sensitivity (79-93%) and specificity (88-95%).

CONCLUSIONS

The "U-Sniff" test is feasible for children starting at age 3 years. In children aged ≥4 years, it is a reliable and valid method to distinguish between normal olfactory function and anosmia.

IMPACT

Olfactory testing is reliable and valid starting at an age of 4 years. The study adds a systematic evaluation of olfactory testing in young children. Results of this study are especially interesting for clinicians in the diagnosis of olfactory dysfunction.

Normative data for olfactory threshold and odor identification in children and adolescents

OBJECTIVE

Although previous studies have demonstrated the feasibility and validity of olfactory testing in children and adolescents using the "Sniffin' Sticks" odor threshold and "U-Sniff" odor identification test, normative data obtained in a large sample for these tests are missing. Aim of this study was therefore to obtain normative data of healthy children and adolescents for olfactory assessment.

MATERIAL AND METHODS

Olfactory testing was conducted using the "Sniffin' Sticks" olfactory threshold (THR) and the 12-item "U-Sniff" odor identification (ID) test. The data were collected from 490 children and adolescents (234 girls, 257 boys) between the age of 6 and 17 years (mean age: 11.2 ± 3.4 years). In line with previous studies, participants were divided into subgroups regarding their age: i) 6-8 years, ii) 9-11 years, iii) 12-14 years and iv) 15-17 years.

RESULTS

All participants were able to perform the task. Neither sex nor age significantly influenced THR. Girls outperformed boys in ID. In addition, the youngest age group scored lower than the three other age groups on the "U-Sniff" odor identification test. Using the 10th percentile to distinguish normosmia from a reduced sense of smell the following values were obtained for the four age groups: i) THR 4.25 points, ID 7 points, ii) THR 5.0 points, ID 9 points, iii) THR 4.75 points, ID 10 points and iv) THR 5.5 points, ID 10 points.

CONCLUSION

The present study provides normative data for olfactory assessment in children and adolescents using both an olfactory threshold and a suprathreshold test to distinguish between normosmia and a reduced sense of smell using the 10th percentile.

Olfactory perception in children

The ability to smell is important for protection from danger and quality of life, even in children. Although smell loss is rare in children, it can be indicative of some childhood disorders and may be useful for understanding some disorders. This paper reviews the methods and results of behavioral testing olfaction in children, with an emphasis on odor identification, the most common method of assessing the sense of smell in both children and adults. The Pediatric Smell Wheel® is described as a relatively new and powerful tool for testing olfaction in children as young as 4 years of age. An example of its use in testing children with a childhood disorders (autism spectrum disorder, ASD) is provided in addition to a review of the literature on smell function in ASD. It is possible to reliably test sense of smell in children as young as 4 years old and many studies have shown that performance improves with age and can be impacted by childhood disorders. Sex differences in children are briefly discussed. Finally, the paper suggests other methods of testing olfaction in children, such as odor discrimination, that depend less on cognitive factors, which may enhance our understanding of the olfactory capabilities of young children.

Effects of diversity in olfactory environment on children's sense of smell

Diversity in children's everyday olfactory environment may affect the development of their olfactory abilities and odor awareness. To test this, we collected data on olfactory abilities using the Sniffin' Sticks and odor awareness with Children's Olfactory Behaviors in Everyday Life Questionnaire in 153 preschool children and retested them one and a half year later. Parents completed an inventory on children's exposure to a variety of odors and on their own odor awareness using the Odor Awareness Scale. We controlled for the effects of age and verbal fluency on the children's performance. We found that the children's odor identification and discrimination scores differed as a function of parental odor awareness. Although these effects were rather small, they were commensurate in size with those of gender and age. To the best of our knowledge, this study is the first to present evidence that diversity in children's olfactory environment affects variation in their olfactory abilities and odor awareness. We suggest that future studies consider the long-term impact of perceptual learning out of the laboratory and its consequences for olfactory development.

Developmental Fine-tuning of Human Olfactory Discriminability

Unlike vision or audition, human olfaction is generally considered evolutionarily ancient and well-functioning at birth, yet there have been few empirical data on the development of olfactory acuity. The current study has assessed olfactory discriminability in children aged 3 to 6 years with 16 pairs of single-compound odorants that differ in various degrees in structure and smell. We report a significant improvement over age in young children's overall olfactory discriminability. Critically, such improvement is modulated by the degree of structural similarity between odorants independent of odor familiarity. Our findings indicate that odor representations in the olfactory system are fine-tuned during early childhood (3-6 years of age) to allow refined discrimination. Moreover, they suggest the need to take molecular similarity into consideration in the evaluation of olfactory discrimination in pediatric populations.

Olfactory threshold and odor discrimination ability in children - evaluation of a modified "Sniffin' Sticks" test

The clinical diagnostics of olfactory dysfunction in children turns out to be challenging due to low attention span, insufficient linguistic development and lack of odor experiences. Several smell tests have been developed for adults. Most of these examinations take a relatively long time and require a high level of concentration. Therefore, the aim of the current study was to evaluate an odor discrimination and olfactory threshold test using the frequently used “Sniffin’ Sticks” in children and adolescents in a simplified two-alternative-forced-choice version (2AFC) and compare it to the original three-alternative-forced-choice test (3AFC). One-hundred-twenty-one healthy participants aged between 5 and 17 years took part in this study. Within each of the two sessions participants underwent olfactory testing using the modified 2AFC as well as the standard 3AFC method. A better test-retest reliability was achieved using the original 3AFC method compared to the modified 2AFC. This was true for the odor discrimination as well as the olfactory threshold. Age had a significant influence on both tests, which should be considered when testing young children. We discuss these findings with relation to the existing norms and recommend using the 3AFC version due to a better test-retest reliability to measure olfactory function in children.

Effects of age and cognition on a cross-cultural paediatric adaptation of the Sniffin' Sticks Identification Test

Objectives

To study the effects of age and cognition on the performance of children aged 3 to 18 years on a culturally adapted version of the 16 item smell identification test from Sniffin' Sticks (SS16).

Methods

A series of pilots were conducted on 29 children aged 3 to 18 years old and 23 adults to produce an adapted version of the SS16 suitable for Brazilian children (SS16-Child). A final version was applied to 51 children alongside a picture identification test (PIT-SS16-Child) to access cognitive abilities involved in the smell identification task. In addition 20 adults performed the same tasks as a comparison group.

Results

The final adapted SS16-Child was applied to 51 children with a mean age of 9.9 years (range 3-18 years, SD=4.25 years), of which 68.3% were girls. There was an independent effect of age (p<0.05) and PIT-SS16-Child (p<0.001) on the performance on the SS16-Child, and older children reached the ceiling for scoring in the cognitive and olfactory test. Pre-school children had difficulties identifying items of the test.

Discussion/Conclusions

A cross-culturally adapted version of the SS16 can be used to test olfaction in children but interpretation of the results must take age and cognitive abilities into consideration.

Positive relationship between odor identification and affective responses of negatively valenced odors

Hedonic ratings of odors and olfactory preferences are influenced by a number of modulating factors, such as prior experience and knowledge about an odor’s identity. The present study addresses the relationship between knowledge about an odor’s identity due to prior experience, assessed by means of a test of cued odor identification, and odor pleasantness ratings in children who exhibit ongoing olfactory learning. Ninety-one children aged 8–11 years rated the pleasantness of odors in the Sniffin’ Sticks test and, subsequently, took the odor identification test. A positive association between odor identification and pleasantness was found for two unpleasant food odors (garlic and fish): higher pleasantness ratings were exhibited by those participants who correctly identified these odors compared to those who failed to correctly identify them. However, we did not find a similar effect for any of the more pleasant odors. The results of this study suggest that pleasantness ratings of some odors may be modulated by the knowledge of their identity due to prior experience and that this relationship might be more evident in unpleasant odors.

Changes of olfactory abilities in relation to age: odor identification in more than 1400 people aged 4 to 80 years

The currently presented large dataset (n = 1,422) consists of results that have been assembled over the last 8 years at science fairs using the 16-item odor identification part of the “Sniffin’ Sticks”. In this context, the focus was on olfactory function in children; in addition before testing, we asked participants to rate their olfactory abilities and the patency of the nasal airways. We reinvestigated some simple questions, e.g., differences in olfactory odor identification abilities in relation to age, sex, self-ratings of olfactory function and nasal patency. Three major results evolved: first, consistent with previously published reports, we found that identification scores of the youngest and the oldest participants were lower than the scores obtained by people aged 20–60. Second, we observed an age-related increase in the olfactory abilities of children. Moreover, the self-assessed olfactory abilities were related to actual performance in the smell test, but only in adults, and self-assessed nasal patency was not related to the “Sniffin’ Sticks” identification score.

Olfactory function in healthy children: normative data for odor identification

BACKGROUND

Olfactory disorders in children may be encountered frequently in the common ear, nose, and throat (ENT) practice. The need for objective measurements in the diagnosis, treatment, and evaluation of olfaction is present. However, for young children most olfactory tests need further normative data to be useful in clinical practice. Therefore, this study aimed to provide normative data in children and to determine possible parameters that influence odor identification test outcome.

METHODS

In 201 healthy children reflecting the Dutch population, the Sniffin' Sticks screening test was performed and possible outcome determinants (age, height, gender, weight, peak nasal inspiratory flow, previous ENT surgery, and parental smoking habits) were assessed.

RESULTS

Age, gender, and previous ENT surgery seem to influence significantly the outcome of the olfactory test.

CONCLUSION

In a general population-based sample of children, normative data of the Sniffin' Sticks screenings test are supplied as well as possible determinants of outcome.

Odor identification testing in children and young adults using the smell wheel

OBJECTIVE

Olfaction is important for nutrition, safety, and quality of life. Detecting smell loss in young children can be difficult, since many children with olfactory deficits do not recognize their problem and may even pretend to smell. The short attention span of some young children precludes testing with longer standardized olfactory tests. Currently there is a dearth of pediatric smell tests. In this study we evaluated the performance of 152 children and young adults on a game-like rotating "Smell Wheel" odor identification test. This forced-choice test, which can be self-administered, was designed to capture the child's imagination and to provide a standardized test measure with odors known to young children using a minimum number of trials.

METHOD

Thirty 4-5-year olds (10 female), 62 6-7-year olds (17 female), 30 10-11-year olds (18 female) and 30 18-19-year olds (15 female) were tested. Analysis of variance was used to assess the influences of sex and age on the test scores.

RESULTS

All participants completed the simple and rapid test protocol. Test performance and age-related changes analogous to those obtained using longer tests were observed. Test scores of participants who self-administered the test were equivalent to those for whom the test was administered by the experimenter.

CONCLUSION

Good compliance and olfactory test findings congruent with literature results were obtained using the Smell Wheel, suggesting that this test may be useful in assessing olfactory function in pediatric settings where attentional demands are compromised and test time is limited.

Optimizing oral medications for children

BACKGROUND

Active pharmaceutical ingredients that taste bitter and/or irritate the mouth and throat are aversive to children as well as many adults. Effective methods of avoiding unpleasant tastes for adults (eg, encapsulating the medicine in pill, capsule, or tablet form) are problematic because many children cannot or will not swallow these. The unpalatable flavor of the medicine can thwart the benefits of even the most powerful of drugs. Failure to consume medication may do the child harm and can even be life-threatening.

OBJECTIVES

This article provides an overview of the current knowledge of the sensory capabilities and preferences of children as it relates to flavor, defined here as the combined input of taste, smell, and chemical irritation. The methods used to evaluate flavor perception in children are reviewed. Recent scientific advances are summarized that shed light on why the bitter taste of oral pharmaceuticals is an ongoing formulation problem and how discoveries of novel flavor molecules and modulators of bitter tastes hold considerable promise for the future. Alternative methods for evaluation of the palatability of medicines are described.

METHODS

The Eunice Kennedy Shriver National Institute of Child Health and Human Development sponsored a Pediatric Formulation Initiative workshop on December 6 and 7, 2005, in Bethesda, Maryland. Information for this article was gathered from literature reviews that were then discussed during this workshop as well as during several conference calls with the Taste and Flavor Working Group members. Terms for the MEDLINE search (1970-2007) included infant, children, taste, olfaction/smell, flavor, chemical senses, palatability, sensory testing, pharmaceutical, and medicines.

RESULTS

Children have well-developed sensory systems for detecting tastes, smells, and chemical irritants, and their rejection of unpalatable medications is a reflection of their basic biology. Sugars, salt, and other substances reportedly reduce the bitterness of several pharmaceuticals. Adding pleasant flavor volatiles such as bubble gum may help induce children to consume a medicine, but such volatile compounds are not effective in suppressing the strong bitter tastes associated with some medications. Also, because individual experiences and culture mainly determine which odors are attractive, a universally appealing volatile flavoring agent may be difficult to identify. Sensory panelists who are sensitive to the pediatric palate, which is different from adults, and new techniques involving animal models, isolated parts of the receptor cells, and even electronic devices that detect taste and flavor are among the tools that may be used to evaluate the palatability of medications and predict compliance among pediatric populations.

CONCLUSIONS

Although there are no easy solutions to this dilemma, children's acceptance of many medicines can be improved by applying the knowledge gleaned from basic research in the chemical senses. Further development and validation of sensory methods will provide a better understanding of the sensory world of the child. This understanding, combined with new technologies and results of animal model studies, will enhance drug acceptance and compliance in pediatric populations. A better understanding of the scientific basis for distaste and how to ameliorate it is a public health priority.

Human awareness and uses of odor cues in everyday life: Results from a questionnaire study in children

The Children's Olfactory Behavior in Everyday Life questionnaire was developed to assess attention to, and uses of, odors in real-life situations, and to evaluate individual variations. The tool comprises 16 items prompting self-reports of active seeking, awareness and affective reactivity to odors of food, people and the environment. Children (102 girls, 113 boys) aged 6–10 years participated in the study. The results revealed that girls were significantly more olfaction-oriented than boys, especially towards the odors of people, self and the environment. An increasing ability of children to describe the odor facets of their perceptual world was found between 6 and 10 years, partly due to ameliorating verbal skills. Finally, owning an “attachment object” was linked to olfactory reactivity to odors, especially in social and affective contexts. Overall, this research contributes to expand our understanding of the behavioral importance of odors in children and its individual variations, and it brings additional arguments against the prevalent concept of functional microsmaty applied to the human species.

Intranasal trigeminal function in children

The aim of the study was to investigate trigeminal function in children compared with that of adults. Trigeminal sensitivity was assessed using a lateralization task where participants were requested to identify the side of the nose to which an odorous stimulus was presented. The ability to localize the sensation is largely based on trigeminal function. A total of 344 people participated (191 females, 153 males; mean age 12 y [SD 7 y 9 mo], range 5-54 y). Eucalyptol (EUC) was administered as a mixed olfactory-trigeminal stimulant; phenylethyl alcohol (PEA) was used as a control stimulant with minimal trigeminal impact. In addition, sensitivity to vibration was assessed as a somatosensory control. With regard to all age groups, PEA could not be localized whereas this was easily possible for EUC. However, the ability to localize EUC increased with age, which was not the case for PEA. No sex-related difference was found for odour localization. These results provide data for normal intranasal trigeminal function in children. They also indicate that trigeminal sensitivity is already well-developed in children.

Olfactory deficits, cognition and negative symptoms in early onset psychosis

BACKGROUND

Smell identification deficits (SID) are common in adult schizophrenia, where they are associated with negative symptoms and lower intelligence. However, smell identification has not been examined in adolescents with early onset psychosis, wherein diagnosis is often obscure, and there are few prognostic predictors.

METHOD

We examined smell identification, diagnosis, neuropsychological performance and symptoms in 26 well characterized adolescents with early onset psychosis, age 11-17 years.

RESULTS

SID existed in the sample and were more common in patients with schizophrenia and psychotic depression than in patients with psychosis NOS and bipolar disorder. As in adults, SID were significantly associated with greater negative symptoms and lower verbal IQ. However, the associations of verbal IQ (and other verbal tasks) to smell identification in this pediatric sample were explained by the relation of both of these types of variables to negative symptoms.

CONCLUSIONS

SID existed across this sample of youths with psychotic disorder, and were specifically related to typical characteristics of schizophrenia, such as negative symptoms and lower intelligence, but not to features of bipolar disorder, such as grandiosity. SID is a characteristic of early onset psychosis that may be useful for prognostic purposes.

Olfactory evaluation in children: application to the CHARGE syndrome

OBJECTIVE

To find an efficient tool for testing olfactory function in children and use it to investigate a group of children with CHARGE (coloboma, congenital heart disease, choanal atresia, mental and growth retardation, genital anomalies, and ear malformations and hearing loss) syndrome.

METHODS

We adapted for children an olfaction test that had just been validated in an adult French population and investigated a control group of 25 healthy children aged 6 to 13 years. We then tested the olfactory capacity of a group of 14 children with CHARGE syndrome, aged 6 to 18 years. A questionnaire was completed with the parents about their children's feeding difficulties and their ability to recognize odors in everyday life. We recorded and scored the histories of feeding behavior anomalies, the visual and auditory status, and current intellectual levels. MRI of the olfactory tracts and bulbs was analyzed for 9 of 14 children.

RESULTS

We showed that healthy children have similar olfactory function to that of the adult control group, which was representative of the general population, without any difference for either gender or age. We also showed that all children with CHARGE syndrome had olfactory deficiency. Half of them were anosmic, and the others had olfactory residual function (hyposmic). We found no association between olfactory deficiency and feeding behavior, visual or auditory impairment, or intellectual level. Parental subjective evaluations were accurate for only half of the group. All of the MRIs showed anomalies of the olfactory tracts and bulbs varying from moderate hypoplasia to complete aplasia, without any relation between the radiologic and the functional results.

CONCLUSIONS

Olfaction can be assessed in children, even the young and disabled. Our results support the proposition that rhinencephalon anomalies should be included as a major criterion for the diagnosis of CHARGE syndrome.

Analysis of the olfactory capacity of healthy children before language acquisition

The absence of a method for evaluating the olfaction of infants and children without structured language led us to perform a longitudinal study of the behavioral responses of very young children. The aim was to establish a tool for verifying a child's olfactory ability during a pediatric examination. A total of 107 subjects were observed and filmed during a regular olfactory activity. Three years of filmed observations were analyzed and showed three types of stable behavioral responses that we consider to be specific to olfactory stimulus: modification of respiratory rhythm, fixed stare, and decrease of mobility. These responses were observed for 98% of the subjects in 100% of the first presentations of the odorized tissue. Response time was not influenced by age, socioeconomic situation, or position in the family, but it was influenced by ethnic background. These responses constitute items allowing the first step of an objective assessment of a prelanguage child's olfaction without the subject's verbal participation.