Understanding Posterior Cortical Atrophy

Lead Investigator: Professor Nick Fox
PhD student: Manja Lehmann

Institution: University College London
Grant type: PhD
Duration: 3 years
Amount: £75,000

Scientific Title: Visual deficits and posterior cortical atrophy: a behavioural and imaging study.

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

People with 'typical' Alzheimer's disease most commonly display symptoms such as memory problems due to the areas of the brain affected by the disease. Less common forms of the disease such as Posterior cortical atrophy (PCA) show different symptoms. People with PCA show difficulties with processing the visual world due to the areas of the back of the brain, which process visual information, being affected by the disease.

Loss of brain cells within the 'outside', or cortex, of the brain, (known as cortical atrophy), is seen in both in people with 'typical' Alzheimer's disease and those with PCA. Manja used a specific type of brain scan called magnetic resonance imaging (MRI) to investigate the pattern of brain cell loss and the nature of visual problems in people with PCA. The results were compared with those generated in people with 'typical' Alzheimer's disease.

What were the key results, and how will this help in the fight against dementia?

The researchers found that people with PCA had most brain cell loss in the back of the brain, which was different from the tissue loss reported predominantly in the hippocampus (an area of the brain important for memory) of people with 'typical' Alzheimer's disease. The patterns of loss fit with what is known about the back of the brain being involved in processing visual information.

Despite the early differences in brain cell loss and symptoms between the two types of Alzheimer's disease, as the disease progresses, regions across the whole brain become affected by cell loss during both types.

During this project, more detailed psychological tests to assess different types of visual problems in people with PCA were developed. These tests showed that vision is not affected in the same way in all people with PCA and that the nature of the visual problems varies to a great extent.

Recognising that this variability exists between people with PCA and with other forms of Alzheimer's disease is important in terms of both research and to improve the support and information provided to people who are affected.

What happened next? Future work and additional grants

The PhD student (Manja Lehmann) has been awarded a post-doctoral fellowship from  Alzheimer's Research UK. This position will be conducted at the Dementia Research Centre in London in collaboration with the Memory and Aging Centre in San Francisco

Read a further summary article of this project

How were people told about the results? Conferences and Publications

Publications

• Lehmann M., Barnes J., Ridgway G.R., Ryan, N.S., Warrington E.K., Crutch S.J., Fox N.C. 2011. Global grey matter changes in posterior cortical atrophy: a serial imaging study. Alzheimer & Dementia. 2012; Feb 23. PMID 22365384
  
• Kennedy J., Lehmann M., Sokolska M.J., Archer H., Warrington E.K., Fox N.C., Crutch S.J. 2011. Visualising the emergence of posterior cortical atrophy. Neurocase. 2011; Oct 25. PMID 22026812
  
• Koedam E.L.G.E., Lehmann M., van der Flier, W.M., Scheltens P., Pijnenburg, Y.A.L., Fox N.C., Barkhof F., Wattjes M. 2011. Visual assessment of posterior atrophy: Development of a MRI rating scale, European Radiology. 2011; Dec;21(12):2618-25. PMID 21805370.
  
• Goll J.C., Kim L.G., Hailstone J.C., Lehmann M., Buckley A., Crutch S.J., Warren J.D. 2011. Auditory object cognition in dementia. Neuropsychologia, 49(9), 2755-2765. PMID 21689671 (open access paper).
  
• Lehmann M., Koedam E.L.G.E, Barnes J., Bartlett J., Ryan N.S., Pijnenburg Y.A.L., Barkhof F., Wattjes M.P., Scheltens P., Fox N.C. 2011. Posterior cerebral atrophy in the absence of medial temporal lobe atrophy in pathologically-confirmed Alzheimer's disease. Neurobiology of Aging. 2012; Mar;33(3):627. doi:10.1016/j.neurobiolaging.2011.04.003 PMID 21596458.
  
• Lehmann M., Barnes J., Ridgway G.R., Wattam-Bell J., Warrington E.K., Fox N.C., Crutch S.J., 2011. Basic visual function and cortical thickness patterns in Posterior Cortical Atrophy. Cerebral Cortex. 2011; Sep;21(9):2122-32. doi:10.1093/cercor/bhq287. PMID 21310781.
  
• Barnes J., Ridgway G.R., Bartlett J., Henley S.M., Lehmann M., Hobbs N., Clarkson M.J., MacManus D.G., Ourselin S., Fox N.C. 2010. Head size, age and gender adjustment in MRI studies: a necessary nuisance? Neuroimage, 53(4), 1244-1255. PMID 20600995.
  
• Crutch S.J., Lehmann M., Gorgoraptis N., Kaski D., Ryan N., Husain M., Warrington E.K. 2010. Abnormal visual phenomena in posterior cortical atrophy: static motion, after-image, reverse size and room tilt illusion effects. Neurocase, 17(2), 160-177. PMID 20818540 (open access paper).
  
• Barnes J., Mitchell L.A., Kennedy J., Barker S., Lehmann M., Nordstrom R.C., Frost C., Smith J.R., Garde E., Rossor M.N., Fox N.C., 2010. Does registration of serial MRI improve diagnosis of dementia? Neuroradiology 52(11), 987-995. PMID 20195590.
  
• Lehmann M., Rohrer J.D., Clarkson M.J., Ridgway G.R., Scahill R.I., Modat M., Warren J.D., Ourselin S., Barnes J., Rossor M.N., Fox N.C., 2010. Reduced cortical thickness in the posterior cingulate gyrus is characteristic of both typical and atypical Alzheimer's disease. Journal of Alzheimer's disease. 20(2):587-98. PMID 20182057.
  
• Lehmann, M., Douiri, A., Barnes, J., Chan, D., Rossor, M.N., Fox, N.C., 2010. Atrophy patterns in Alzheimer's disease and semantic dementia: A comparison of FreeSurfer and manual measurements. Neuroimage 49 (3), 2264-2274. PMID 19874902.
  
• Gutiérrez-Galve L., Lehmann M., Hobbs, N.Z., Clarkson M.J., Ridgway, G.R., Crutch, S.J., Ourselin S., Schott, J.M., Fox, N.C., Barnes, J., 2009. Patterns of cortical thickness according to ApoE genotype in Alzheimer's disease. Dementia and Geriatric Cognitive Disorders 28 (5), 476-485. PMID 19940480.
  
• Lehmann M., Crutch S.J., Ridgway G.R., Ridha B.H., Barnes J., Warrington E.K., Rossor M.N., Fox N.C., 2009. Cortical thickness and voxel-based morphometry in posterior cortical atrophy and typical Alzheimer's disease. Neurobiology of Aging. 2011; Aug;32(8):1466-76. doi:10.1016/j.neurobiolaging.2009.08.017. PMID 19781814.