Terry Quinn, MD

Keeping up to date with stroke research is tough. In Stroke, we offer a monthly Literature Synopses section where we summarize recent, important stroke research. Sharing stroke research should not be limited to stroke-ologists. For the last Clinical Synopses, I created a plain language version for Blogging Stroke that (hopefully) was accessible to a non-specialist audience. Feedback was positive, and so I am offering another Clinical Synopses summary. 

You can read the original Synopses article here: Quinn TJ. Stroke Literature Synopses: Clinical Science. Stroke. 2018

I am keen to hear feedback, good and bad, via Twitter @DrTerryQuinn

For this month’s Clinical Synopses, I selected three papers concerned with psychological problems and stroke. People who have experienced stroke often rate memory and thinking problems as their most distressing symptom. However, it has taken a while for the clinical stroke community to appreciate the importance of these symptoms. Psychological problems in stroke remain under-researched compared to ‘physical’ issues. Thankfully, things are changing. Various high-profile, international initiatives are working to tackle stroke-related psychological issues, and I hope that in future blog posts, I can tell you about new treatments for these problems. In the meantime, my chosen papers all have a diagnosis theme.

The first step in treatment is defining the condition of interest. In the field of stroke-related memory and thinking problems, we have a diagnostic problem. We tend to use the term ‘vascular cognitive impairment’ (VCI), but researchers and clinicians can’t agree on what this means. Various experts have created definitions of VCI, but there has been little agreement and no single definition is accepted by everyone.

A recent guideline should hopefully bring some much needed consistency. The VICCS group (Vascular Impairment of Cognition Classification Consensus) has created a new set of VCI definitions.[1] The group took a slightly different approach to creating their definitions that I think will be appreciated. Rather than create new definitions from scratch, the VICCS definitions are based on the best aspects of existing definitions. Recognising that there is important VCI research happening all over the world, the VICCS writing group took opinions and feedback from a host of international experts.

The final VICCS classification recognizes different problems that can all be described as VCI; these are: ‘Post Stroke Dementia’; ‘Mixed Dementia’ (often a mix of stroke damage and Alzheimer’s disease); Subcortical Ischaemic Dementia (where there is a blood flow problem deep in the brain); and Cortical Ischaemic Dementia (where there is a blood flow problem to the brain surface).

This classification makes sense to me, and I am hopeful that this new system will be used by the stroke and dementia community. Personally, I will be disappointed if, in a few years, the Clinical Synopses section reports on another attempt to standardize VCI.

For some people, problems with memory and thinking get worse over time. In Alzheimer’s disease, there is a journey that begins with subtle memory problems (a state often called mild cognitive impairment) and eventually progresses to dementia. It is not certain if the same pattern of change is seen when memory and thinking problems are caused by stroke. A team of UK researchers investigated this natural history in a group of over 13000 people.[2] The team performed regular memory and thinking tests with the participants and also looked for the presence of heart and blood vessel problems.

The team found that all heart and blood vessel problems seemed to increase the chances of developing dementia. However, certain medical conditions were particularly associated with early memory and thinking problems; these included stroke and diabetes mellitus. The team also found that different medical conditions seemed to cause differing patterns of memory and thinking problems. They suggest that the term vascular cognitive impairment (VCI) may be an over-simplification. In fact, VCI may represent many differing processes that depend on the person’s underlying medical conditions. Perhaps, we will need a new VCI definition after all.

Cerebral amyloid angiopathy (CAA) is a blood vessel problem that often causes memory and thinking problems. At one time, CAA was considered a rare disease. As we become better at looking for it, we are finding that CAA is more common that we first thought. The moment of CAA diagnosis requires sophisticated brain imaging using MRI scanning. This is a problem, as not everyone has access to an MRI scanner, and even if MRI is available, not everyone can tolerate the lengthy scans required.

A team from Edinburgh, Scotland, has developed a method of assessing for CAA that uses conventional CT brain scans and a blood test.[3] CAA often causes bleeding. The Edinburgh team found that the pattern of blood seen on a CT scan can accurately distinguish CAA from other causes of bleeding. What I particularly liked about this paper was that the authors have created online teaching materials to help us detect CAA features on CT brain scans. Using the website and with a bit of practice, I think I will be making the diagnosis of CAA more often and more confidently. The next CAA challenge is to find a treatment…

References:

  1. Skrobot OA, O’Brien J, Black S, Chen C, DeCarli C, Erkinjuntti T, et al. The Vascular Impairment of Cognition Classification Consensus Study. Alzheimers Dement. 2017;13:624–633. doi: 10.1016/j.jalz.2016.10.007
  2. Stephan BCM, Minett T, Muniz-Terrera G, Harrison SL, Matthews FE, Brayne C. Neuropsychological profiles of vascular disease and risk of dementia: implications for defining vascular cognitive impairment no dementia (VCI-ND). Age Ageing. 2017;46:755–760. doi: 10.1093/ageing/afx016
  3. Rodrigues MA, Samarasekera N, Lerpiniere C, Humphreys C, McCarron MO, White PM, et al. The Edinburgh CT and genetic diagnostic criteria for lobar intracerebral haemorrhage associated with cerebral amyloid angiopathy: model development and diagnostic test accuracy study. Lancet Neurol. 2018;17:232–240. doi: 10.1016/S1474-4422(18)30006-1