Cognition is an important function of the brain so we can gain knowledge and understanding. These mental processes include thinking, knowing, remembering, judging, planning, understanding and responding to information and problem-solving. They are vital for our everyday functions – whether that’s getting ready for work, remembering where we left our house keys, reminiscing about times from our past or planning a holiday in the future.

According to the Voice of the Patient Report, published by the United Mitochondrial Disease Foundation, cognitive problems are amongst the key issues facing patients with mitochondrial disease every day, significantly impacting their independence and quality of life. 

There is a great deal of variation in the cognitive decline that affects those living with mitochondrial disease and its progression is not fully understood. Studies have shown that patients with mitochondrial diseases are frequently affected by cognitive impairment and suffer from reduced neuro-connectivity in several areas of the brain.

There are many different aspects to cognition but they all play their part in enabling us to live our lives to the full. As such, cognitive difficulties can significantly affect school and job performance, and undermine independence and quality of life. In some instances, symptoms are so severe that they can be classified as dementia.


For most of us we don’t consider the brain power required to watch a film, make our way to work each day on our usual route or enjoy a conversation with a group of friends. But for those living with mitochondrial disease, delayed information processing can be a major burden. The concentration required and the attention needed for such everyday activities can be too much, significantly impacting daily life.


Storing information that we might need in the future, recalling an instruction to solve a problem or remembering experiences we would take pleasure in recalling, can also be difficult. Whether that’s remembering a PIN number, the date of a loved-one’s birthday or an anniversary or, in the more immediate term, the name of somebody you’re introduced to at a party. Mitochondrial diseases can significantly impact long and short term memory and the information we’re able to remember day-to-day.


Or imagine looking out of the window and seeing a cat in the garden. You know it’s a cat. It might be yours but you can’t find the word ‘cat’ in your head to describe it. This is the effect that cognitive impairment can have on language skills, one of the higher-level functions of our brain. Even just finding the right words when telling a story can be difficult or remembering how to write down words and phrases you might want to use.

Regardless of the degree of severity, the impact of such cognitive difficulties on those living with mitochondrial disease can be debilitating. Changes in thinking and memory can be among the most confusing and scary potential symptoms, because of their impact across our whole lives. They are also some of the least talked about.

Thankfully, clinicians are increasingly addressing these aspects of mitochondrial disease with their patients through screening and cognitive testing, to make patients aware of potential symptoms and ensure that appropriate care and management of symptoms can be provided.

Studying cognitive decline at Khondrion

The significance of cognitive decline in mitochondrial disease makes it is a key focus of our research at Khondrion. That’s why our current trials are focusing on the potential of our investigational medicine to influence cognitive functioning.

As well as monitoring the daily activities of patients in our trials and using measurements to assess quality of life, we’re using computer-based cognitive tests, an approach that has been used in thousands of studies. The tests, which can be easily produced on a tablet device, allow us to measure a specific area of cognition very carefully. For example, to measure visual attention we use a test involving images of playing cards.

In this test, the playing cards displayed are all either red or black jokers. The patient is asked whether the card displayed in the center of the screen is red. They respond by pressing the yes key when the joker card is red and no when it is black. The computer measures the speed and accuracy of each response, something we can monitor over the course of a patient’s time in the trial.