Electroencephalographs (EEGs) are diagnostic tools that veterinarians and researchers use to detect changes or dysfunction in a horse’s brain activity. An EEG can help in the evaluation of disease, trauma, the effect of medication, even thought processes. The catch is, conducting EEGs on horses gets complicated.
In humans, it’s easy enough. The electrodes that conduct information on the brain’s activity can be attached directly to our skin. Humans can also be instructed to stand still for the scan–critical, since movement can interfere with the quality of the recordings. With our horses, it’s not so simple.
Often, equine EEGs rely on invasive techniques requiring anesthesia, such as surgically implanted electrodes or needles placed under the skin. Noninvasive methods exist, but may require shaving the horse’s forehead to glue on electrodes and immobilizing the horse, typically in metal stocks.
Now the good news: French researchers led by Hugo Cousillas, who holds a doctorate in neuroscience and teaches at the University of Rennes 1, have devised a solution–a portable, adjustable EEG-recording headset for horses. No shaving required and the horse doesn’t even have to stand still.
The headset places four electrodes on the horse’s forehead, plus one behind the left ear. It’s held in place by a harness of large rubber bands and incorporates an amplifier and recorder. Since it doesn’t need to be wired to any other device or outlets, it allows the horse to have total freedom of movement while being monitored. The researchers say it can be placed on a horse in less than five minutes and can be adjusted to fit different-sized heads.
To test the quality of EEG recordings made with the headset, the researchers set up a trial at the French national equitation school of Samur using five horses: three French saddlebreds and two Anglo-Arabians, aged 7 to 9 years old; four mares and one gelding. Each horse wore the headset during a 15-minute session on two consecutive days while EEG recordings were made.
Researchers found that the results from their EEG headset recordings were similar to those obtained by other EEG methods.
In a report published in Frontiers in Veterinary Science, the researchers noted that “being able to record EEG in freely moving animals in their familiar settings may … considerably change the knowledge we have of brain processing in horses.” While acknowledging this was a small study and additional research is needed, they added that the headset “will be a precious tool for future studies [aimed] at evaluating in-the-field situations, individual differences in cognitive processes or vigilance states in different contexts such as sleep or anesthesia.”
This article was originally published in the August 2017 issue of Practical Horseman.