[Cough frequency monitoring: current technologies and clinical research applications]

Cough is a common symptom of many respiratory diseases, and parameters such as frequency, intensity, type and duration play important roles in disease screening, diagnosis and prognosis. Among these, cough frequency is the most widely applied metric. In current clinical practice, cough severity is primarily assessed based on patients' subjective symptom descriptions in combination with semi-structured questionnaires. In spite of convenience, this paradigm is inherently limited by recall bias and poor quantifiability. This results in only moderate correlation with objective cough assessments. Over the past two decades, rapid developments in signal processing, mobile communication, speech recognition, and artificial intelligence have enabled the objective measurement of cough frequency in clinical research. Objective cough frequency monitoring is now widely regarded as the gold standard for assessing cough severity. This review summarizes the principles and technologies of objective cough frequency monitoring, and outlines the characteristics and clinical research applications of currently available monitoring devices.