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Hypo unawareness could disrupt brain activity involved in attention and decisions

Hypo unawareness disrupts blood flow in the brain

Our researchers have found hypo unawareness may disrupt blood flow to areas of the brain involved in decision making and attention in people with Type 1 diabetes.

A team at King’s College London, led by Dr Pratik Choudhary, think these changes may be why some people stop being able to feel low blood sugars and treat them.

A snapshot of hypo unawareness

When blood sugar levels drop too low it’s called a hypo. Hypos can be frightening, unpleasant, or in their worst cases, fatal. So it’s important to know what the signs are and to act quickly to treat a hypo.

But around a quarter of people with Type 1 diabetes can lose their ability to spot the warning signs of a hypo, known as hypo unawareness, putting them at greater risk of dangerous side-effects.

With our funding, Dr Choudhary is investigating why the brain stops recognising hypos with the hope that this will help us find ways to treat or prevent hypo unawareness. The research team studied 19 people with Type 1 diabetes who were hypo unaware, looking at how their brains respond to hypos and comparing them to 15 people with Type 1 who were able to detect low blood sugar levels.

The team used specialised MRI scans to see which parts of the brain responded to low blood sugar levels. They took images when volunteers were hypo (at 2.6 mmol/l) and at a safe blood sugar level of 5.0 mmol/l.

They discovered that – when hypo – brain activity was lower in the thalamus and prefrontal cortex of people who were hypo unaware. These regions of the brain are involved in attention, decision making and the judgement of negative consequences.

This could explain why people don’t recognise that their blood sugar levels are too low. And sheds light on previous research that found that people who experience lots of hypos often delay treating their hypo or struggle to make the right treatment decision.

Dr Munachiso Nwokolo, who worked on the study, explained:  

"Different parts of the brain are in charge of monitoring and managing stress. After many episodes of the same type of stress, such as lots of hypos, areas of the brain like the thalamus and frontal regions, involved in arousal and decision-making, do not react in the same way. These changes in the way the brain reacts to hypos, in people with impaired hypo awareness, may be why some find it especially difficult to stop hypos.”

Imaging the brain

In the MRI scan – known as three dimensional pseudo-continuous arterial spin labelling – radio waves are used to magnetically tag the molecules of water in our blood. This makes the water magnetic so the MRI machine can take a picture of blood flow in the brain, to identify which brain regions are being activated during a hypo.

The volunteers were carefully monitored throughout the study and were given glucose immediately after the scan to bring their blood sugar levels back up into a safe range. They were then supported to avoid hypos for the next 48 hours.

As a next step, the researchers plan to find out if the changes in brain activity they’ve discovered can be reversed, and whether this can help restore hypo awareness.

“Hypo unawareness can be debilitating and dangerous, with a huge impact on people with diabetes’ quality of life.

“This research helps us to understand how and why hypo unawareness develops, by creating a picture of what happens in the brain during a hypo. This could open up new ways of helping people to avoid hypos and get their awareness back.

“New treatments would make a real difference for people with diabetes, removing anxiety, making living with the condition easier and, crucially, protecting people from the potentially serious consequences of hypos”

Dr Elizabeth Robertson, our Director of Research

This study was published in Diabetes Care

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