Early Assessment of Dementia Risk in PARKINSON’S DISEASE
PARKINSON’S DISEASE is usually considered a “movement disorder”, with symptoms of tremor, rigidity and slowness that affect a person’s ability to move. But a small percentage of people diagnosed with PARKINSON’S DISEASE go on to develop cognitive impairments, dementia or even Lewy body dementias.
“This study opens the door to further research, for example, on medication or on non-pharmacological approaches such as transcranial magnetic stimulation. It’s important for these patients to be identified very quickly before they develop dementia so that a therapeutic approach can be adapted to their specific needs”, says Dr. Oury Monchi, the principal investigator of this study.
Dr. Monchi and Dr. Hanganu and their team of researchers affiliated with the Universitè de Montrèal, used magnetic resonance imaging to find there was a thinning and atrophy in some brain regions of people with mild cognitive impairment who were diagnosed in early stages of PARKINSON’S DISEASE. They discovered that as the disease progressed, the thinning and atrophy of these areas progressed along with an increase in cognitive decline. The study followed a cohort of 32 subjects in the early stages of PARKINSON’S DISEASE and a control group of 18 healthy subjects for a period of 20 months.
Cortical thinning has been proven to occur corresponding to the progression of the disease but has not been studied in relation to the development of cognitive impairment. This study found a more rapid progression of thinning in the temporal, occipital, parietal and supplementary motor areas of patients with mild cognitive decline as compared to patients who had no cognitive impairments and healthy controls. They also found that the amygdala and nucleus accumbens also lost significant volume in patients with cognitive impairments. As a specific pattern of deterioration in these brain regions correlates to the presence of mild cognitive impairment in the early stages of PARKINSON’S DISEASE, these findings could lead to a biomarker predicting the subsequent development of dementia.
A. Hanganu, C. Bedetti, C. Degroot, B. Mejia-Constain, A.-L. Lafontaine, V. Soland, S. Chouinard, M.-A. Bruneau, S. Mellah, S. Belleville, O. Monchi. Mild cognitive impairment is linked with faster rate of cortical thinning in patients with Parkinson’s disease longitudinally. Brain, 2014; DOI:10.1093/brain/awu036
Review by Marcia McCall