See me, feel me. Using physiology to validate behavioural observations of emotions of people with severe or profound intellectual disability

Background Behavioural observations are the most frequently used source of information about emotions of people with severe or profound intellectual disabilities but have not yet been validated against other measures of emotion. In this study we wanted to validate the behavioural observations of emotions using respiration (rib cage contribution, total breath duration, inspiratory time, expiratory time, tidal volume, mean inspiratory flow, minute ventilation) and heart rate variability. Method Twenty-seven participants were presented with four negative and four positive stimuli. During the presentation the participants' respiration and heart rate variability was measured. Each behaviour of the participant was coded as emotive or not. Results We found the hypothesised higher percentage rib cage contribution, marginal lower mean inspiratory flow and lower heart rate variability when the expressed emotions became more positive. Conclusions These results validate the use of behavioural observations to make inferences about emotions.