Developmental changes in nasal airflow patterns

Re-evaluating the nasal cycle by long-term rhinoflowmetry: most individuals demonstrate a 'mixed' nasal cycle

BACKGROUND

The nasal cycle seems to be more complex than a strictly alternating swelling of the nasal mucosa. Long-term rhinoflowmetry (LRFM) allows continuous investigation of changes in nasal airflow over 24 hours (24h). We evaluated the various types of nasal cycle with LRFM over 24 hours and investigated the influence of age and gender.

METHODS

LRFM was continuously performed over 24h in 55 rhinologically healthy subjects (36 female, 19 male). The LRFM flow curves were examined for phases of the 'classical' 'in-concert' 'one-side' and'no-cycle' cycle types. Subjects were divided into 4 age subgroups (19-29; 30-49; 50-69; >70 years). Correlations of age and gender with the individual cycle forms were analyzed.

RESULTS

85.5% of the subjects presented a 'mixed' nasal cycle within 24h. 'classical' nasal cycle was seen most often (92.7% vs. 'in-concert' 56.4% vs. 'one-sided' 18.2% vs. 'no-cycle' 5.5%). Older age groups significantly more often presented the 'no-cycle' type. A tendency was seen towards a mixed nasal cycle with increasing age. The mixed nasal cycle was significantly more often seen in the female subjects.

CONCLUSIONS

LRFM is an easy-to-use measurement tool. The 'mixed' nasal cycle predominates. However, all 4 different cycle types can be detected, alternating over 24h in each subject. Moreover, the cycle type varies with age.

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.

Children's susceptibility to chemicals: a review by developmental stage

Concerns about adequate protection of children's health from chemicals in the environment have created a need for research to identify how children's risks differ from adults'. A systematic review of factors that affect child sensitivity throughout development may be useful for research and practice in this area. We summarized available literature and other peer-reviewed information on factors that affect pharmacokinetics and exposure in an age-based developmental framework. Biological processes related to chemical absorption (gastrointestinal, dermal, and pulmonary), distribution, metabolism, and excretion were considered, along with reference to behaviors and other factors associated with child-specific exposures. The available information was summarized in a timeline of maturation for biological processes. It indicates variability in the duration and timing of maturation for each biological function. Possible implications for understanding pediatric sensitivity to environmental chemicals are discussed in light of factors affecting exposure through development. Themes that emerge from the evidence are presented as hypothesis-generating conclusions. This approach may be useful for evaluating developmental trends of susceptibility, and for identifying time periods and/or chemical classes of particular concern and thus important to consider in risk assessment.

Detection of the nasal cycle

The nasal cycle is a fluctuation of nasal patency due to the stages of congestion and decongestion of the nasal mucosa on both the right and left nasal conchae. We compared the effectiveness of the rhinostereometer in detecting the presence of a nasal cycle with the acoustic rhinometer whose effectiveness we have demonstrated in previous studies. The rhinostereometer measures the horizontal range of the most anterior portion of the inferior turbinate. The acoustic rhinometer measures the volume and various cross-sectional areas of the nostril using a pulse emitted from a sound tube. Among some of the subjects tested, it was found that rhinostereometer and acoustic rhinometer measurements of nasal patency correlated reasonably well with r values up to 0.78. The overall correlation between rhinostereometry and acoustic rhinometry was not as strong at r = 0.36. Observed variations between rhinostereometry and acoustic rhinometry could be a result of certain confounding variables that may have altered the nasal cycle between measurements.

Evaluation of the nasal cavity by acoustic rhinometry in normal and allergic subjects

With acoustic rhinometry, one can detect a difference in response to a topical decongestant between normal and allergic subjects at the minimal cross-sectional area. The minimal cross-sectional area corresponds in most cases to the anterior end of the inferior turbinate or the first valley, which occurs after the nose piece of the acoustic rhinometer on the acoustic rhinometry graph. Allergic patients typically have an increase in nasal mucosal swelling, which leads to a decrease in the nasal volume and area and, subsequently, to an increase in congestion. In this study acoustic rhinometry was used to test normal and allergic subjects before and after the application of a topical decongestant (1% phenylephrine (Neo-Synephrine)). Symptoms were measured by a five-point scale. Results showed that increasing symptom scores demonstrated a trend toward being related to decreasing area as measured at the minimal cross-sectional area or nasal valve. The average total percent change at the minimal cross-sectional area was calculated for both groups and compared. The normal subjects had an average total percent area change at the minimal cross-sectional area of 15.6% ± 14.8%, and the allergic subjects had a percent change of 24.6% ± 20.8%. This represents a significant difference between the normal and allergic subjects in response to the topical decongestant at the minimal cross-sectional area ( p = 0.04). However, the average total percent change was not significantly different between the two groups at the second and third valleys. At the second valley, the normal subjects had a percent change of 40% ± 17.5%, and the allergic subjects had a percent change of 36% ± 18.5%. At the third valley, the normal subjects had a percent change of 35% ± 15.4%, and the allergic subjects had a percent change of 32% ± 20.6% ( p = 0.4 and 0.5, respectively). The total area was calculated by adding measurements from both right and left nasal cavities for each subject in an attempt to control the effect of the nasal cycle. Acoustic rhinometry makes it possible to detect a trend in the relationship between either a decrease in area at the minimal cross-sectional area or a decrease in the total volume from 0 to 7 cm into the nasal cavity and congestion. A statistically significant difference between normal and allergic subjects in their response to a topical decongestant at the minimal cross-sectional area was detected by acoustic rhinometry at the nasal valve.

Aging of the normal nose in adults

Like other organs, the nose changes as the body ages. A review of the literature reveals a basic understanding of the aging process in the nose but a paucity of documentation and few organized studies. This study was designed to identify systematically the agerelated changes in the normal, nondiseased adult nose. A nasal-sinus laboratory was created, and a computerized patient database was developed. Four separate investigations were conducted. First, 111 subjects ranging in age from 21 to 94 years of age were studied prospectively using 135 variables. The following data were collected: history, symptoms, physical examination, rhinomanometry, ciliary beat frequency, smell testing, and incentive spirometry. Second, photographs of a separate group of 105 subjects 20 to 86 years of age were studied to ascertain the facial cephalometric changes that occur with aging. Third, a histopathologic examination of the nasal septum was performed in 20 additional subjects to evaluate the cellular changes that accompany aging. Finally, an epidemiologic study analyzing the prevalence of various nasal complaints by age was conducted, based on a review of more than 11,000 patient charts from surgeries and office visits. A number of specific age-related changes in the nose were identified, including an increased likelihood of certain nasal complaints, a pattern of increasing airflow resistance, and a decrease in physical abnormalities in the nasopharynx. The appearance of the nose, as measured by the nasolabial angle and the height/length ratio, was also found to change with age.

Assessment of an abbreviated odorant identification task for children: a rapid screening device for schools and clinics

To validate the level of olfactory performance of children, we tested 825 volunteers, aged 4-17 years, with an abbreviated form of our pediatric odorant identification task. The test consisted of sniffing and identifying five odorants (baby powder, bubble gum, candy cane, licorice and peach). Mean olfactory scores increased as a function of age, reaching a plateau of about 94-95% correct at 8 years of age. In general, girls out-performed boys. Physicians require a test instrument such as the one we have devised to allow them to diagnose olfactory dysfunction in children. The present task is particularly applicable in screening large numbers of children in clinics or schools because it can be administered easily and rapidly. Adult subjects with olfactory dysfunction also performed poorly on this odorant identification task designed for children. Therefore, we expect that our odorant identification task will also detect children with severe olfactory dysfunction.