When it comes to cats and science we just can’t get enough and now researchers have made tiny crochet hats for them in a bid to understand more about their brain activity and how it relates to chronic pain. 

Over 25 percent of adult cats have chronic pain associated with radiographic osteoarthritis and the percentage increases with age. A big challenge for veterinarians is to measure and treat pain in animals. Currently, treatments for osteoarthritis in cats can have bad side effects and are fairly limited. However, the team are looking at ways to modulate pain in the cats by stimulating their other senses, this has been proven to help in humans with the same condition. 

The team thought that by using electroencephalography (EEG) to measure the brain activity in cats, they could measure their responses to different sensory stimuli. This could then be compared between healthy cats and those cats with chronic pain. However, keeping electrodes on the heads of the kitty recruits proved challenging, until the researchers came up with a novel idea. Crochet hats for cats. 

“We decided to use [crochet hats] because during the acclimation, the habituation period, when we put the electrodes on, sometimes the cat shakes his head and the electrodes just fall down. So we kept putting the electrodes on again and again. So we saw online that there are some crochet hats that exist just for cute reasons. And we decided to try to do one for our EEG, just to save time," PhD student and paper co-author Aliénor Delsart, from the University of Montreal, told IFLScience. 

The researchers used 11 cats that were trained to stay sitting or lying down and acclimated to the room and the people involved in the study over four 15-minute sessions over a period of two weeks. The hats successfully kept the electrodes on the heads of the animals allowing the team to take EEG recordings as they responded to smells and light changes. 

For different stimuli, the team presented the cats with grapefruit essential oil that was on the other side of the carrier and so could not be seen. The container was opened for 20 seconds then followed by a two-minute break. The cats were also exposed to different wavelengths of light – red, blue, green – in a random order with a two minute break between each exposure. 

"It's a next step to better know the chronic pain in cats. And I hope that it will help better characterize the chronic pain and to manage it correctly, because now we have some problems to manage, osteoarthritic pains in cats, because it's difficult to diagnose and to treat appropriately," said Delsart. 

The knitted hats helped keep the electrodes in place during the experiment and prevented cats from being able to chew or play with any wires. While some results were discarded due to too much noise in the signals from the cats moving, the results did allow the the researchers to look at the brain waves as a reaction to the stimuli. 

The team believe this is the first report of doing EEGs on awake cats using surface electrodes and hope that it will expand the understanding of chronic pain and possible therapeutic treatments in the future. They might even try it on other species. 

"I think it's possible. For horses, there [are] also some EEG that are feasible. And for dogs, I know that there [are] also EEG that are performed. We probably want to try this for other species too," said Delsart.

The paper is published in the Journal of Neuroscience Methods.