New Approaches to Identifying and Measuring Pain

Abstract

The search for objective measures of pain is ongoing. In human pain research, self-reporting is considered to be the gold standard against which prospective measures are compared. Because self-reporting is not possible in non-linguistic species, studies that utilise standardised noxious stimuli are often used to evaluate prospective measures of pain. Two approaches to the quantification of animal pain have emerged in recent years that seem to offer significant advances over previous techniques. Quantified analysis of the electroencephalographic response to noxious stimulation has been used in many species of mammal. This technique has the advantage that it is carried out under general anaesthesia and so has the potential to give insight into pain without actually subjecting animals to pain. In conscious animals, ethological quantification of behaviour is able to identify pain-related behaviours with much greater precision and assurance than older methods of behavioural analysis. This paper will discuss both techniques with examples taken from the work of the Massey University Comparative Analgesia Group (Johnson et al. 2005;