  The development of a system for the automatic, objective and reliable
detection of cough events is a need underlined by the medical literature for
years. The benefit of such a tool is clear as it would allow the assessment of
pathology severity in chronic cough diseases. Even though some approaches have
recently reported solutions achieving this task with a relative success, there
is still no standardization about the method to adopt or the sensors to use.
The goal of this paper is to study objectively the performance of several
sensors for cough detection: ECG, thermistor, chest belt, accelerometer,
contact and audio microphones. Experiments are carried out on a database of 32
healthy subjects producing, in a confined room and in three situations,
voluntary cough at various volumes as well as other event categories which can
possibly lead to some detection errors: background noise, forced expiration,
throat clearing, speech and laugh. The relevance of each sensor is evaluated at
three stages: mutual information conveyed by the features, ability to
discriminate at the frame level cough from these latter other sources of
ambiguity, and ability to detect cough events. In this latter experiment, with
both an averaged sensitivity and specificity of about 94.5%, the proposed
approach is shown to clearly outperform the commercial Karmelsonix system which
achieved a specificity of 95.3% and a sensitivity of 64.9%.
