Recurrent Hypoglycaemia in Type 1 Diabetes (HypoBrain)

• EEG [ Time Frame: 2 years ] [ Designated as safety issue: No ]
  EEG will be analysed in order to see whether there are any differences between aware and unaware patients during hypoglycaemia. It is our hope that the result can help develop an alarm before the patient experiences severe hypoglycaemia.
  
  

• QTc interval [ Time Frame: 2 years ] [ Designated as safety issue: Yes ]
  The investigators want to investigate whether the QTc complex gets wider during hypoglycaemia. This is in order to see whether long QTc could be the explanation behind sudden dearth in diabetes patients.
  
  
• Skin temperature [ Time Frame: 2 years ] [ Designated as safety issue: No ]
  Skin temperature will be measured by thermography. The investigators want to see whether the skin can be used as a biomarker for hypoglycaemia.
  
  
• Auditory evoked potentials [ Time Frame: 2 years ] [ Designated as safety issue: No ]
  The investigators what to see whether there is any difference in auditory evoked potentials (AEP) between aware and unaware diabetic patients. The subject will hear a commen and a rare sound in a 4:1 ratio while the EEG is recorded. Afterwards the data is analysed and the AEPs are adressed.
  
  
• Cognitive function [ Time Frame: 2 years ] [ Designated as safety issue: No ]
  The investigators want to address whether there are any differences in the cognitive function between aware and unaware patients.The cognitive function will be adressed by the use of computerised cognitive function tests (CalCAP) and Stroops tests as well.
  
  

Background:

Patients with type 1 diabetes are at risk of severe hypoglycaemia as a severe side effect to insulin therapy, in particular subjects who have lost warning of hypoglycaemia (hypoglycaemia unawareness). The episodes are associated with impaired quality of life and can lead to permanent brain damage and death.

During hypoglycaemia a low frequent activity can be seen with electroencephalography (EEG) as cognitive function declines. Repeated hypoglycaemic episodes result in down regulation of counter regulatory and symptomatic responses. It is not known whether a similar phenomenon is present for cerebral dysfunction as judged by EEG changes and cognitive function.

The purpose is to investigate the activity in the brain, the cognitive function, and the skin temperature when patients are exposed to repeated hypoglycaemia. The results will show whether the response to hypoglycaemia will change after repeated episodes.

The methods:

The investigators will recruit two groups of patients: Patients with hypoglycemia awareness and patients with hypoglycaemic unawareness.

The patients are exposed to hypoglycaemia on two concomitant days while the investigators record EEG and perform cognitive tests. Skin temperature is assessed by the use of thermography. If the patient has hypoglycaemic unawareness a 4 week period follows where the glycaemic control is loosened to avoid hypoglycaemia episodes and the patients is then exposed to hypoglycaemia again.

The prospect:

It is the investigators hope that results can contribute to improved understanding of hypoglycaemic EEG changes and skin temperature changes. This could be of potential benefit for patients with hypoglycaemic unawareness.