Validated Methods of Cough Assessment: A Systematic Review of the Literature

Abstract

Background: Cough is a common symptom for which patients often seek medical advice and consume vast amounts of drugs. It is a real challenge for both the physician and the clinical researcher to evaluate a cough’s clinical importance and its precise response to treatment. Objectives: This systematic literature review has the following objectives: first, to make an inventory of the validated tools for assessing cough, and second, to investigate the extent to which the results of various assessment methods can be correlated. Methods: Two independent investigators searched the Medline, Embase, and Cochrane databases for validation studies on cough assessment tools. Results: Thirty-four studies were included. Several ambulatory cough monitors automatically identify cough and have been validated in a limited number of patients. Three cough-specific quality-of-life scales (Leicester Cough Questionnaire, Cough Quality of Life Questionnaire, and Burden of Cough Questionnaire) have been validated. No validation studies of descriptive scores or visual analogue scales were found. The correlations between quality-of-life scores and cough frequency were good. The correlations between descriptive scores or visual analogue scales and more objective methods, such as cough frequency monitoring or quality-of-life scores, were inconsistent. Conclusion: Cough-specific quality-of-life questionnaires can provide valid outcomes for research into cough. Although the current developments in cough monitoring devices are promising, further studies on a larger scale, under more realistic conditions, and for different patterns of cough are required before they can be recommended for widespread use.

Validation of the Polish Version of the Chronic Cough Quality of Life Questionnaire (Leicester Cough Questionnaire)

“…Measurement of cough severity is difficult, as it is a subjective ailment which depends on the cough intensity, the patients' perception of cough severity and the impact of the cough on quality of life [8,15]. Cough intensity may be objectively measured by cough frequency monitors, while cough severity may be measured by using tools such as VAS, descriptive scores and diaries or cough specific QOLQs [2,8,9,16].…”

“…Cough intensity may be objectively measured by cough frequency monitors, while cough severity may be measured by using tools such as VAS, descriptive scores and diaries or cough specific QOLQs [2,8,9,16]. The results of subjective cough questionnaires only moderately correspond to the results of objective methods such as cough monitoring techniques [17].…”

Comparison of Nocturnal Cough Analysis in Healthy Subjects and in Patients with Cystic Fibrosis and Primary Ciliary Dyskinesia: A Prospective Observational Study

“…This approach is problematic as patients’ reports on cough are highly subjective and correlate weakly with objective cough monitoring [2, 3]. Objective cough monitoring possibly improves the evaluation of cough and may result in improved treatment decisions, but the feasibility of cough monitoring devices is poorly studied in these patients [4]. …”

Cough frequency monitors: can they discriminate patient from environmental coughs?

“…Modern sound-based cough monitors make use of compact digital recording devices that are now available. Automated or semi-automated processes have been developed, which enable a more efficient detection and counting of cough events on sound recordings of many hours' duration (2,10,11). A potential limitation of sound-based cough monitors is compromise of their accuracy by the potential for environmental coughs (coughs from persons other than the patient) to contaminate the recording (2,10,11).…”