Modifications of the nasal cycle in patients with hypothalamic disorders: Kallmann's syndrome

The nasal cycle before and after nasal septoplasty

PURPOSE

Septoplasty is one of the most frequently performed operations in patients with septal deviation of the nose. The aim of this surgical intervention is to reduce nasal obstruction and to achieve a physiological nasal breathing. The nasal cycle plays a crucial role in this. The aim of this study was to investigate nasal breathing and the nasal cycle after septoplasty over a long period of time and under everyday conditions.

METHODS

We examined 22 healthy subjects and 19 patients with nasal septal deviation. They participated in two sessions separated by an interval of three months. Shortly after the first session patients received nasal septoplasty. Testing included multiple questionnaires regarding nasal breathing and olfactory function, anterior rhinoscopy, rhinomanometry, acoustic rhinometry, and long-term rhinoflowmetry over 24 h.

RESULTS

Nasal septoplasty was associated with subjectively improved nasal breathing and nasal patency comparable to that in healthy subjects. The severity of nasal obstruction was reduced. Nasal airflow and the hydraulic diameter increased on the deviated side of the nose while the inspiratory resistance did not significantly change. In addition, the number of phases of the nasal cycle decreased on the nondeviated side. Hence, the surgery was associated with a more even distribution of phases on both sides of the nose.

CONCLUSION

Nasal septoplasty leads to a subjectively satisfactory result in patients with pathological septal deviation of the nose. In particular, septoplasty appears to be accompanied by a more even distribution of the nasal cycle across the two nasal cavities.

Relationship Between Nasal Cycle, Nasal Symptoms and Nasal Cytology

Background

The nasal cycle is the spontaneous congestion and decongestion of nasal mucosa that happens during the day. Classically, 4 types of nasal cycle patterns have been described: (1) classic, (2) parallel, (3) irregular, and (4) acyclic. Hypothalamus has been considered as the central regulator even if several external factors may influence its activity.

Objective

The aim of the study was to evaluate the presence of a correlation between nasal cycle pattern, nasal cytology and nasal symptoms.

Methods

Thirty healthy volunteers have been enrolled in the study. All subjects completed a Sino-Nasal Outcome Test-22 questionnaire and a Visual Analog Scale (VAS) for nasal obstruction. The nasal cycle was studied by means of peak nasal inspiratory flow. Nasal cytology has been used to evaluate the presence of local nasal inflammation.

Results

Nineteen subjects showed a parallel nasal cycle pattern, while 11 showed a regular one. A parallel pattern was present in 60% of asymptomatic subjects and in 67% of the symptomatic one ( P = 1). VAS for nasal obstruction did not show a significant difference between the 2 patterns of the nasal cycle ( P = .398). Seventeen subjects had a normal rhinocytogram, while 13 volunteers showed a neutrophilic rhinitis; 53.8% of the subjects with a neutrophilic rhinitis showed a parallel pattern, while the remaining 46.2% had a regular one. In the case of a normal cytology, 70.6% of the volunteers had a parallel pattern and 29.4% had a regular one. Differences between the 2 groups were not statistically significant ( P = .575).

Conclusion

Rhinitis with neutrophils seems to not influence the nasal cycle pattern. Based on the present results, the pattern of nasal cycle does not influence subjective nasal obstruction sensation.

Measuring and Characterizing the Human Nasal Cycle

Nasal airflow is greater in one nostril than in the other because of transient asymmetric nasal passage obstruction by erectile tissue. The extent of obstruction alternates across nostrils with periodicity referred to as the nasal cycle. The nasal cycle is related to autonomic arousal and is indicative of asymmetry in brain function. Moreover, alterations in nasal cycle periodicity have been linked to various diseases. There is therefore need for a tool allowing continuous accurate measurement and recording of airflow in each nostril separately. Here we provide detailed instructions for constructing such a tool at minimal cost and effort. We demonstrate application of the tool in 33 right-handed healthy subjects, and derive several statistical measures for nasal cycle characterization. Using these measures applied to 24-hour recordings we observed that: 1: subjects spent slightly longer in left over right nostril dominance (left = 2.63 ± 0.89 hours, right = 2.17 ± 0.89 hours, t(32) = 2.07, p < 0.05), 2: cycle duration was shorter in wake than in sleep (wake = 2.02 ± 1.7 hours, sleep = 4.5 ± 1.7 hours, (t(30) = 5.73, p < 0.0001). 3: slower breathing was associated with a more powerful cycle (the extent of difference across nostrils) (r = 0.4, p < 0.0001), and 4: the cycle was influenced by body posture such that lying on one side was associated with greater flow in the contralateral nostril (p < 0.002). Finally, we provide evidence for an airflow cycle in each nostril alone. These results provide characterization of an easily obtained measure that may have diagnostic implications for neurological disease and cognitive state.

A model for the central control of airflow patterns within the human nasal cycle

BACKGROUND

The nasal cycle exhibits mainly reciprocal changes in nasal airflow that may be controlled from centres in the hypothalamus and brainstem. This study aims to gather new knowledge about the nasal cycle to help develop a control model.

METHOD

Right and left nasal airflow was measured in healthy human subjects by rhinomanometry. This was performed over 7-hour periods on 2 study days separated by approximately 1 week. The correlation coefficient for nasal airflow was calculated for day 1 and day 2.

RESULTS

Thirty subjects (mean age, 22.7 years) completed the study. The correlation coefficient for nasal airflow varied between r = 0.97 with in-phase changes in airflow and r = -0.89 with reciprocal changes in airflow. The majority of r values were negative, indicating reciprocal changes in airflow (50 out of 60). There was a tendency for r values to become more negative between day 1 and day 2 (p < 0.001).

CONCLUSION

A control model involving a hypothalamic centre and two brainstem half centres is proposed to explain both the in-phase and reciprocal changes in airflow associated with the nasal cycle.

Nasonasal reflexes, the nasal cycle, and sneeze

The nasal mucosa is a complex tissue that interacts with its environment and effects local and systemic changes. Receptors in the nose receive signals from stimuli, and respond locally through afferent, nociceptive, type C neurons to elicit nasonasal reflex responses mediated via cholinergic neurons. This efferent limb leads to responses in the nose (eg, rhinorrhea, glandular hyperplasia, hypersecretion with mucosal swelling). Anticholinergic agents appear useful against this limb for symptomatic relief of a "runny nose." Chronic exposure to allergens can lead to hyperresponsiveness of the nasal mucosa. As a result, receptors upregulate specific ion channels to increase the sensitivity and potency of their reflex response. Nasal stimuli also affect distant parts of the body. Nerves in the sinus mucosa cause vasodilation; the lacrimal glands can be stimulated by nasal afferent triggers. Even the cardiopulmonary system can be affected via the trigeminal chemosensory system, where sensed irritants can lead to changes in tidal volume, respiratory rate, and blink frequency. The sneeze is an airway defense mechanism that removes irritants from the nasal epithelial surface. It is generally benign, but can lead to problems in certain circumstances. The afferent pathway involves histamine-mediated depolarization of H1 receptor-bearing type C trigeminal neurons and a complex coordination of reactions to effect a response.

Effects of the Amazonian psychoactive beverage Ayahuasca on binocular rivalry: interhemispheric switching or interhemispheric fusion?

An early theoretical analysis supposed changes in hemispheric integration as the basis of altered state of consciousness induced by psychoactive drugs. Brain imaging studies revealed right cortical activation after administration of hallucinogens. Recent studies on binocular rivalry suggest that interhemispheric switching is the neural substrate of the perceptual oscillations observed during dichoptic stimulus presentation. The current study tested perceptual alternation in ceremonial participants, who ingested the South American hallucinogenic beverage ayahuasca, to examine the claim that there might be changes in interhemispheric function under the influence of hallucinogens. Ingestion of ayahuasca resulted in a decrease of rivalry alternation rates, increased length of one percept and there was evidence of phenomenal fusion. The findings are in line with results of brain activation studies and support the concept of interhemispheric fusion in altered states of consciousness.

Influence of age on the 'nasal cycle'

The nasal cycle is classicially defined as a side-to-side fluctuation in nasal engorgement and airflow, with period lengths ranging from approximately 1 to 5 hours. This cycle, as well as its variants (e.g., cyclic changes on one side of the nose only), is produced by alterations in autonomic tone of the nasal vasculature and reportedly correlates with a number of ultradian rhythms, including asymmetries in left:right cerebral electroencephalographic (EEG) activity and differential performance on visual/spatial psychological tasks. Since the pacemaker for the nasal cycle is believed to lie within the suprachiasmatic nucleus of the hypothalamus, and this nucleus evidences degeneration in later life, we sought to determine whether the nasal cycle or its variants changes with age. To achieve this end, we used a liquid crystal thermography exhalation monitor to measure relative airflow of the two nasal chambers at 15-minute intervals for 6 hours in 60 people representing four age categories: 18 to 29 years (n=12); 30 to 49 years (n=15); 50 to 69 years (n=13); and 70 to 85 years (n=20). Overall, the proportion of subjects exhibiting the alternating rhythmicity associated with the classic nasal cycle decreased with age. No association was present between nasal cycle parameters and scores on the Mini-Mental State Examination (MMSE). The results suggest that the classic nasal cycle may be a marker for age-related central nervous system changes.

Phasic changes in human nasal and skin blood flow: relationship with autonomic tone

To assess the autonomic control of the microcirculation in human skin and nasal mucosa, the spontaneous fluctuations of a laser Doppler signal recorded on forearm skin and nasal mucosa were compared with heart rate fluctuations and the respiratory signal in 11 healthy subjects by means of spectral analysis. Possible direct mechanical-thermal effects of airflow on the nasal mucosa were evaluated by comparing recordings obtained when the subjects were breathing through either the nose or the mouth. Comparison of the spectral analysis of the signal obtained for skin and nasal mucosa blood flow allowed us to define the characteristics of the autonomic tone of the microcirculation in these two areas. The skin is mainly influenced by sympathetic activity, and the nasal blood flow is regulated by both sympathetic and parasympathetic activity.

Developmental changes in nasal airflow patterns

Airflow through each nasal passage was measured every 10 min throughout a 5-h period in 48 subjects whose ages ranged from 3 to 17 years. The data were subjected to statistical techniques that characterize and quantify periodicities in a time series. Such analyses revealed that for the majority of children younger than 7 years of age, the airflow through the two nostrils changed either randomly (50%) or in parallel (31%). Between the ages of 7 and 10 years, however, the distribution of airflow patterns characteristic of adults emerged, such that the incidence of reciprocity increased to 63%, and the incidence of random and parallel patterns decreased to 31% and 6%, respectively. A similar distribution was evidenced in the 11- to 17-year-old subjects (56% reciprocal, 38% random, 6% parallel). Although the total airflow through the nose also increased with age, the increased inspiratory flow rates could not account for the developmental changes evidenced in airflow patterns.