Trained dogs can detect the odour of Parkinson’s Disease

Abstract

A definitive diagnostic test for PD remains elusive, so identification of potential biomarkers may shed light on methods for diagnosis and facilitate early intervention. Excess sebum secretion and skin pathology are recognised symptoms of early PD. It is likely these result in a unique signature of volatile organic compounds that could be used to identify early stages of disease. Numerous medical conditions produce distinctive odours, and dogs have been trained to detect many of these. A single previous study, suggested that dogs can also be trained to detect Parkinson’s Disease. In this study, two dogs were trained to distinguish sebum swabs obtained from drug naïve, and medicated Parkinson’s patients from swabs from control participants. After 38-53 weeks of training on 205 samples (90 target and 115 control), the dogs were tested in a double-blind trial using 60 control and 40 target samples from drug-naïve patients. The dogs both showed high sensitivity (proportion of target samples found 70% and 80%) and specificity (proportion of control samples not alerted to 90% and 98%) of alerting response. This trial supports previous findings that dogs can be trained to reliably detect the odour of PD. We suggest there is a potential for dogs to achieve even higher accuracy with increased exposure and refined training methods and to detect early-stage PD, even prior to diagnosis, as well as hard to diagnose PD cases. Further exploration of the factors which affect dogs’ sensitivity and specificity and sample features which affect accuracy of discrimination are now required.