VIDEO BLOG: ASRP Discoveries – Dr. Joel Ramirez
Dr. Joel Ramirez’s open access publication, Subcortical hyperintensity volumetrics in Alzheimer’s disease and normal elderly in the Sunnybrook Dementia Study: correlations with atrophy, executive function, mental processing speed, and verbal memory, is supported by the Alzheimer Society research program.
In this paper, we looked at signs of cerebrovascular disease on MRI scans of 265 patients with Alzheimer’s disease and 100 healthy elderly people who were enrolled in the Sunnybrook Dementia Study. Subcortical hyperintensities are bright spots on MRI and are believed to indicate signs of small vessel disease in the brain. Another example of vascular injury are lacunar infarcts, which appear as dark spots on MRI, and are typically thought of as silent strokes in the brain. In order to properly measure these signs of small vessel disease and other brain measures from each patient’s MRI scan, we used software called Lesion Explorer, which we developed specifically to study dementia and aging populations. We then looked at how these signs of small vessel disease were correlated with behavioural functions such as memory or mental processing speed. After applying Lesion Explorer to the MRI scans, we found that the Alzheimer’s disease patients had less brain overall indicated by less gray matter, less white matter, and more cerebrospinal fluid; but most importantly, we also found that the Alzheimer’s patients had more signs of small vessel disease and silent strokes compared to their healthy elderly counterparts. We then looked at how these brain pathologies correlated with behaviour and found that signs of small vessel disease in the medial middle frontal part of the brain were correlated with executive function, signs of small vessel disease around the ventricles were correlated with speed of mental processing, and those found in the left temporal lobe were correlated with memory. These findings reveal the unfortunate reality that people living with Alzheimer’s are also likely to be living with cerebrovascular disease, and where this small vessel disease manifests in the brain is also likely contributing to their dementia. These signs of small vessel disease may have clinical relevance as potential future targets for treatment in Alzheimer’s dementia.
Read the full publication at: http://alzres.com/content/6/4/49
Joel Ramirez is a 2008 ASRP Doctoral Award recipient from University of Toronto who works under the supervision of Dr. Sandra Black at Sunnybrook Hospital in Toronto.