Changes in the Brain Structure and Volume Detected with a Unique Memory Test
Researchers at Turku University Hospital in Turku, Finland used a specific test of memory and a high powered MRI to measure changes in the gray matter of subjects with PARKINSON’S DISEASE. Their results are reported in the January 16th edition of Journal of Parkinson’s Disease.
In this study, they used 28 subjects who were within 3 years of diagnosis with PARKINSON’S DISEASE but whose daily lives were not in any way affected by cognitive or memory issues and 28 healthy, non-Parkinsonian control subjects.
Previous research has been able to show loss of brain volume related to memory loss in PARKINSON’S DISEASE, but has not been able to compare brain volume and memory problems to specific structures. Part of the problem may lie in the types of tests administered and the Magnetic Resonance Imaging (MRI) data collected. This study used a more precise, advanced form of MRI, called voxel-based morphometry (VBM) that is able to measure three dimensionally the volume of selected brain regions. Together with a unique memory test, they were surprised to find slight morphological changes showing degeneration of the parietal lobe, but only on the right side.
The memory test they used was an incidental free recall test where subjects were shown a list of 30 to 60 words and images but specifically not given any instruction about remembering them. Later they were asked to recall as many of them as they could. The incidental recall test simulates more closely actual real life memory situations, where there is no intention to commit events to memory but where they are remembered freely. Attention is not focused on remembering and no cues are given to assist the memory formation in real life.
In this test, the researchers found there was significant impairment in the PARKINSON’S DISEASE group in both recall and visuospatial control tasks, but that word list learning and executive control tasks were unaffected. While the overall gray matter volume of both groups showed no significant difference, the memory tasks did show smaller volume of gray matter in the right parietal cortex of the PARKINSON’S group, but not in the control group. The researchers suggest that this particular brain region is affected because it is involved in attention to memory and visual images and not to the semantic nature of the task.
Dr. Ulla Ellfolk from the Department of Psychology and Logopedics of Abo Akademi University and the Division of Clinical Neurosciences at Turku University Hospital. Dr. Ellfolk stated “This study is one of the first to link a discrete area of the brain to a cognitive deficit in people at an early stage of PARKINSON’S DISEASE. Clinical studies have shown that free recall is more strongly affected than language, performance on simple attention tasks and visuospatial functioning in newly diagnosed PD patients.”
Brain Volumetric Correlates of Memory in Early Parkinson’s Disease; a Research Report; Ulla Ellfolk, Juho Jouts, Juha O. Rinneb, Riitta Parkkola, Pekka Jokinen, Mira Karrascha; Journal of Parkinson’s Disease 3 (2013) 593–601, IOS Press; DOI 10.3233/JPD-130276
Review by Marcia McCall