How to tell dog cough sounds from other noises using recordings

Abstract

Cough is an important respiratory protective mechanism, which when persistent also contributes to disease pathology. It is therefore both a marker for and a target of therapeutic intervention. In dogs, assessment of cough is subjective, generally based on owner's perceptions of clinical signs. In humans, acoustic cough monitoring provides objective data on cough frequency by examining acoustic waveforms. We hypothesized that healthy mesocephalic dogs would demonstrate characteristic cough waveforms which could be distinguished from other acoustic behaviors (AB); whine, bark, growl, lick, drink, chew and throat-clear. Data were obtained from 10 healthy employee-owned dogs. Acoustic behaviors were recorded using a CTA-laryngeal-microphone and analyzed using RavenPro bioacoustics software for nine objective acoustic parameters (AP). Similarity between AB were assessed using a one-way analysis of similarity (ANOSIM) with a P<0.001 significance level. Inter- and intra-group statistical analysis was performed using a one-way ANOVA on ranks with P<0.05 significance level. With the exception of throat-clear, cough was dissimilar to every other evaluated AB (P<0.0001), with significant differences in one or more of the analyzed waveform parameters (P<0.001 for each). No between-subject differences were identified between cough and throat-clear groups for any parameter. All other behaviors showed statistically significant within-group variation (P<0.001). Cough and throat-clear (a clinically similar mechanism to protect the airways) have repeatable acoustic features that are distinguishable from other common AB and are consistent between dogs. Acoustic monitoring may provide an objective means for evaluating cough frequency and intensity in dogs with respiratory disease and assessing response to therapeutic intervention.