What causes visual hallucinations in dementia with Lewy bodies?

Research project: Molecular Mechanisms Underlying Visual Hallucinations in Dementia with Lewy Bodies

Lead Investigator: Dr Christopher Morris 

Institution: Newcastle University

Grant type: Project

Duration: 30 months

Amount: £178,419

Start Date: June 2013

End Date: November 2015

What was the project, and what did the researchers do?

A common symptom of dementia with Lewy bodies is hallucinations, where the person affected will see very clear and convincing images of people, animals and objects that are not actually there. Visual hallucinations can cause considerable distress to the person with dementia and their carers and are often difficult to treat. Currently it is unclear why such hallucinations occur in DLB. 

The researchers aimed to identify what biochemical changes occur in the brain's visual systems in people with dementia with Lewy bodies who experience visual hallucinations. They also planned to characterise the disease-related changes in specific areas of this visual system in people who experience hallucinations. They compared donated tissue from people with dementia with Lewy bodies who experienced hallucinations with tissue from people with Alzheimer's disease who didn't have hallucinations, and also from people who did not have any neurological disease.

What were the key results and how will this benefit people with dementia?

The researchers found that there are some regions of the brain that appear to be linked to the hallucinations. Brain cells in one particular region, called the pulvinar, are not able to function correctly due to the abnormal activity of a signalling protein known as GABA. The researchers also found the presence of the protein that makes up Lewy bodies, alpha-synuclein, in this region. These two things may be leading to the death of the brain cells in this region. As the pulvinar is important for processing visual information, these could be one reason behind the hallucinations. 

The researchers also investigated another region of the brain called the fusiform gyrus, which has important roles in how we perceive objects, animals and people. No brain cell death was observed in the fusiform gyrus but it was affected by alpha-synuclein, particularly in the area that is involved in perceiving faces. This could explain why people with dementia with Lewy bodies can sometimes see faces that aren't actually there. 

These results give us vital information about the poorly understood causes of hallucinations in dementia with Lewy bodies. Researchers can use this information to find out if there is any way to target these regions with treatments to prevent this distressing symptom. 

What happened next? Future work and additional grants

Dr Morris has been awarded a grant from the Medical Research Council to further investigate the role of the protein GABA in this process. 

How were people told about the results? Conferences and publications

Papers

Erskine D, Taylor JP, Firbank MJ, Patterson L, Onofrj M, O'Brien JT, McKeith IG, Attems JA, Thomas AJ, Morris CM and Khundakar AA. Changes to the lateral geniculate nucleus in Alzheimer's disease but not dementia with Lewy bodies. Neuropathology

Three more papers are being written and planned for submission in early to mid 2016. 

Conferences 

15th March 2014, Brain Awareness Week, Presentations and demonstrations to members of the public at The Great North Museum, Newcastle.

12th May 2014, Presentation to Durham District Rotary Club at the Chester-le-Street Cricket Club, Durham.

11th June 2014, Presentation to Annfield Plain Methodist Church, Durham

16th July 2014, Presentation to AS members at St James Park, Newcastle.

25th September 2014, Presentation to constituency of Andrew Jones, MP for Harrogate and Knaresborough, Harrogate Holiday Inn, North Yorkshire.

29th October 2014, Presentations and demonstrations to members of the public at The Great North Museum, Newcastle.

28th January 2015, Presentation to AS members at Central Square, Newcastle.

21st March 2015, Brain Awareness Week, Presentations and demonstrations to members of the public at The Great North Museum, Newcastle.

27th March 2015, Presentation to AS members on opening of Ashington branch offices, Northumberland.

29th April 2015, Presentation to Durham District Rotary Club at the Chester-le-Street Cricket Club, Durham.

1st June 2015, Presentation to Durham Probus, Durham Community Centre, Durham.

1st September 2015, Presentation to Tynedale U3A, Hexham Methodist Church, Hexham, Northumberland.

24th September 2015, Presentation at Alzheimer's Society Doctoral Training Centre, The Core, Newcastle.

29th September 2015, Presentation to Dementia Action Sunderland, The Athenaeum, Sunderland.

3rd December 2015, Platform Presentation at International Dementia with Lewy Bodies Conference, Fort Lauderdale, Florida, USA. 

3rd December 2015, Poster Presentation at International Dementia with Lewy Bodies Conference, Fort Lauderdale, Florida, USA. 

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