Parkinson’s Disease May Induce Verbal Memory Problems Independently of Dementia

In a recent study published in PLOS One, entitled “Temporal Lobe and Frontal-Subcortical Dissociations in Non-Demented Parkinson’s Disease with Verbal Memory Impairment“, scientists from the University of Florida examined the association between Parkinson’s disease in non-dementia patients and verbal memory impairment. They found that about a quarter of recently monitored patients with Parkinson’s disease suffered from memory problems.

Parkinson’s disease is a degenerative disorder that affects regions of the central nervous system involving body movements. The latter is believed to result from death of the neurotransmitter dopamine-generating cells. Parkinson’s disease commonly occurs in people above the age of 50, but this doesn’t mean that younger individuals are immune to the illness. A number of factors may cause Parkinson’s disease including genetic risk factors and environmental like head injuries, and exposure to pesticides/ heavy metals commonly present in farming areas or in water sources. Patients affected by Parkinson’s disease struggle with movement-related problems like rigidity, shaking, slowness of movement and difficulty with walking.

Other symptoms like behavioral problems, depression, sleep disorder, and troubles with thinking and loss of memory commonly associated with dementia may arise. With respect to the latter, the research team from the University of Florida examined the association between verbal memory loss and Parkinson’s disease in non-dementia patients. In the study, 40 individuals suffering from Parkinson’s disease and 40 healthy control subjects performed two verbal memory evaluations based on repeatable and logical memory tests. Furthermore, all participants in the study were scanned by magnetic resonance imaging to figure out the anatomy/physiology of their central nervous system.

The team set the imaging variable of interests to the area of the brain related to memory, navigation and control of voluntary movements of specific body parts. The results showed that patients suffering from Parkinson’s disease scored worse in verbal memory tests and had smaller volume of the brain region related to memory and navigation. In addition, about 23% of all Parkinson’s disease patients depicted deficit in both memory measurements.

In summary, though the data illustrated that areas of the brain related to memory were significantly shrank in Parkinson’s disease patients when compared to healthy non-Parkinson’s controls, only certain components of the nervous system that transmit signals in the brain (white matter) are actually linked to verbal memory performance. The data also suggested no evidence of contribution from gray matter or frontal white matter regions. Consequently, the researchers think that further investigations of the gray and white matter connectivity are required in order to fully understand memory loss in patients suffering from Parkinson’s disease.