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Assessing chronic pain is a challenge given its subjective dimension. In humans, resting state electroencephalography EEG is a promising tool although the results of various studies are contradictory. Spontaneous chronic pain is understudied in animals but could be of the highest interest for a comparative study. Riding horses show a very high prevalence of back disorders thought to be associated with chronic pain.
Moreover, horses with known back problems show cognitive alterations, such as a lower attentional engagement. Therefore, we hypothesized that the individual EEG power profiles resting state i. Results show that 1 EEG profiles are highly stable at the intra-individual level, 2 horses with elevated back tension showed resting state EEG profiles characterized by more fast beta and gamma and less slow theta and alpha waves.
The proportion of theta waves was particularly negatively correlated with muscular tension along the spine. Resting state quantitative EEG appears therefore as a very promising tool that may allow to assess individual subjective chronic pain experience, beyond more objective measures of tension. These results open new lines of research for a multi-species comparative approach and might reveal very important in the context of animal welfare.
The assessment of pain, and in particular chronic pain, is a major challenge that remains difficult to solve, especially since in addition to the nociceptive stimulation, there is a subjective emotional and cognitive dimension to it [ 1 ]. All authors agree that there is a need for a reliable readout for spontaneous pain, based on a numerical measure, and that would apply on awake unrestrained subjects of different species [ 2 ].
