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

Area of Science:

• Otolaryngology
• Respiratory Physiology
• Sleep Medicine

Background:

• The nasal cycle, characterized by alternating nasal airflow, is more complex than previously thought.
• Long-term rhinoflowmetry (LRFM) enables continuous 24-hour monitoring of nasal airflow changes.
• Understanding nasal cycle variations is crucial for diagnosing nasal airflow disorders.

Purpose of the Study:

• To evaluate diverse nasal cycle types using LRFM over a 24-hour period.
• To investigate the influence of age and gender on nasal cycle patterns.
• To analyze the prevalence of different nasal cycle types in healthy subjects.

Main Methods:

• Continuous 24-hour LRFM was performed on 55 healthy subjects (36 female, 19 male).
• Nasal airflow curves were analyzed for 'classical,' 'in-concert,' 'one-side,' and 'no-cycle' types.
• Subjects were categorized into four age groups, and correlations with gender were assessed.

Main Results:

• A 'mixed' nasal cycle was observed in 85.5% of subjects over 24 hours.
• The 'classical' nasal cycle was most frequent (92.7%), followed by 'in-concert' (56.4%), 'one-sided' (18.2%), and 'no-cycle' (5.5%).
• Older age groups showed a higher incidence of the 'no-cycle' type, with a trend towards mixed cycles in older individuals. Mixed cycles were more prevalent in females.

Conclusions:

• LRFM is a user-friendly tool for assessing nasal airflow dynamics.
• The 'mixed' nasal cycle is the predominant pattern, but all four types can occur within 24 hours.
• Nasal cycle patterns exhibit variations influenced by age and gender.