Do horses get headaches? The need for better neurophysiological techniques to elucidate equine central nociceptive pain syndromes.

This research examines the evidence of headaches and central pain in horses, similar to human symptoms, highlighting the need for improved techniques to identify and treat such conditions. The study discusses using nociceptive withdrawal reflexes for non-invasive assessment, and the possibilities of more invasive neurophysiological techniques for selective evaluation.

About the Research

• The research focuses on the evidence of headaches in horses and compares it to similar conditions in humans such as trigeminal pain syndromes.
• It is based on the analogy that if there are doubts about a horse’s pain, vets should treat it as if it is experiencing pain.
• The study also observes behaviours associated with central pain states in horses. Conditions like idiopathic headshaking in horses show similarities to conditions like human cluster headache, trigeminal neuralgia, and post-herpetic neuralgia.

The Need for Better Techniques

• Since it’s challenging to diagnose neuropathic pain in horses, and there are many unknowns in terms of causes and incidences, there is a need for better diagnostic techniques and understanding of the condition.
• The assessment of the wind-up phenomenon in the equine nociceptive trigeminal system, as carried out by Dr. Kata Veres-Nyéki and her team, is particularly valuable to this end.

Use of Nociceptive Withdrawal Reflexes (NWRs)

• Veres-Nyéki and her team used NWRs, a non-invasive model that evaluates the complete spinal reflex and can thus be used to assess changes in spinal processing.
• Although changes in NWRs don’t indicate the exact nature of the change, they are useful in the quantification of nociceptive processing.
• Numerous studies have utilised NWRs to assess the anti-nociceptive effects of anaesthetic drugs like Butorphanol and other changes to the nociceptive system such as wind-up or central sensitization.

Potential Future Application

• The team anticipates that further developments in neurophysiological techniques could allow for the detection of central processing in the subnucleus caudalis, a specific area of the trigeminal brainstem sensory nuclear complex.
• In the future, these techniques will offer better understanding of equine central nociceptive pain syndromes, opening up opportunities for improved diagnosis and treatment for horses.