Respiratory Function and Voice: The Role for Airflow Measures.

Objective: To clarify the relationship between voice and respiratory function, and to understand the role for airflow measures in the evaluation of voice patients.

Methods: Literature searches of MEDLINE (Ovid) and Web of Science were performed on April 6, 2020, to include articles written in English that both discussed voice in relation to lower respiratory function and reported evaluation of airflow. Search strategies included the keywords voice, respiratory, airflow, and aerodynamic measures. Data were extracted from articles that met inclusion criteria.

Results: Twenty studies were included for review. Fourteen (70%) studies evaluated at least 1 spirometric respiratory measure, including Forced Vital Capacity, Forced Expiratory Volume in 1 second, and Forced Expiratory Flow. Other measures assessed included mean flow rate, mean peak airflow, phonatory airflow, inspiratory airflow, expiratory airflow, and phonation quotient. Notably, four studies which included pulmonary function tests (PFTs) as part of voice evaluation discovered previously undiagnosed respiratory disease in their study populations.

Conclusion: This review confirms that respiratory function contributes significantly to voice and reveals that few studies have explored the role for airflow measures in clarifying this relationship. Including airflow measures such as PFTs in standard voice evaluation may allow recognition of underlying respiratory disease contributing to voice dysfunction. Further research is recommended to establish indications and diagnostic criteria for the use of PFTs in voice patients.