Dr Nina Kazanina - University of Bristol

Pilot Project: 2014 - 2015

Visual and auditory processing in mild cognitive impairment

Scientific title: Visual mismatch negativity in Mild Cognitive Impairment: a follow up study

What did we know already?

There is a great need for improved characterisation of Mild Cognitive Impairment (MCI) and the early identification of those MCI patients for whom impairment represents prodromal Alzheimer’s disease (AD). While memory problems and changes in brain structure are the classic hallmarks of AD there is a growing body of evidence that other brain functions are also disrupted during the early stages of the disease. One of these areas of interest is in vision and visual attention, as the areas of the brain responsible for the processing of visual information have been shown to be vulnerable to AD pathology.

What are the aims of this group?

The group’s overall aim is to better understand the range of brain functions that are affected by the early stages of different forms of dementia. They hope to characterise the changes to perception and attention in dementia, to complement what is already known about changes to memory.

What have they found out so far?

In a recent cross-sectional study they demonstrated that early visual processing and change detection in AD was disrupted compared to healthy older adult controls. They measured these changes using a technique called electroencephalography (EEG), which provides a measure of the brain’s electrical activity by placing sensors on the scalp. EEG is safe, non-invasive and quite comfortable, making it a potentially useful diagnostic tool.

During the same study 26 MCI patients were also tested. With the support of BRACE the group were able to follow up these patients a few years later and determine i) their clinical outcome e.g. conversion to AD, recovery of cognitive function, and (ii) invite them for second test session. This enabled them to add great value to the data already gathered by re-analysing it with the additional crucial information about subsequent clinical outcome. Additionally it provided information on the usefulness of their measures of visual processing and change detection as markers of disease progression. It was found that MCI patients that went on to be later diagnosed with dementia showed AD-like patterns of EEG activity when they were initially tested.

What are they doing next?

They are working with new collaborators at Exeter University who specialise in advanced mathematical techniques for the analysis of biological signals (e.g. EEG). These new techniques will allow them to examine the data that they have already gathered with greater precision and resolution.

Why is this important?

By improving characterisation and diagnosis of the early stages of dementia they can help both the research and patient communities. With further research into the range of brain function that is affected in the early stages of dementia they hope that they can contribute towards the development of cheap, non-invasive early diagnosis tools.