Blood protein EGF may help predict Parkinson’s cognitive issues: Study
Protein's levels significantly lower in patients with impairment
Levels of the protein epidermal growth factor, or EGF, in blood may help predict the risk of cognitive decline in people with Parkinson’s disease, a study reports.
The study, “Correlation between plasma epidermal growth factor and follow-up cognitive decline in Parkinson’s disease,” was published in Neurological Sciences.
Problems with cognition, such as difficulty with memory and information processing, are a fairly common nonmotor symptom of Parkinson’s disease, but not everyone with Parkinson’s will have cognitive issues and it’s difficult to predict which patients are more or less likely to experience these symptoms in the future.
EGF has been reported to have nerve-protecting properties. Here, scientists in China assessed whether EGF levels might help predict the risk of cognitive problems in Parkinson’s patients.
EGF levels and cognitive decline
The study included 135 people with Parkinson’s. At the initial assessment, 29 patients had cognitive impairment as detected by a standardized cognition measurement called the Montreal Cognitive Assessment (MoCA). The other 106 did not.
EGF levels were significantly lower on average in those with cognitive impairment, statistical analyses showed. In fact, data showed a linear correlation between EGF and MoCA scores; patients with lower EGF tended to have worse MoCA scores.
A correlation was also found between EGF levels and scores on the Digit Symbol Substitution Test (DSST), a measure of short-term memory and information processing. Other cognitive assessments, including tests of memory and verbal fluency, didn’t show a significant association with EGF levels, however.
“We observed significant associations between EGF levels and cognitive tasks assessing general cognitive function and information processing speed, suggesting that higher EGF levels may be indicative of better cognitive performance,” the researchers wrote.
The patients who didn’t have cognitive impairment based on MoCA scores were followed for an average of two years after the initial assessment. Further statistical tests showed EGF levels at that first assessment significantly predicted whether patients would develop cognitive impairment over the follow-up.
“In our longitudinal follow-up, we found that baseline [blood levels of] EGF concentrations were associated with follow-up cognitive decline in [Parkinson’s] patients,” the scientists wrote.
Data indicated that about half of patients with EGF blood levels below 49.56 picograms per milliliter would later develop cognitive impairment based on MoCA scores, whereas more than 90%Â of patients with EGF levels above this cutoff wouldn’t later see cognitive impairment.
The researchers called for more studies to validate the results and to see if combining EGF with other blood markers might increase the accuracy of identifying Parkinson’s patients who will go on to have cognitive issues.
“Future studies should consider combining EGF levels with other biomarkers to improve the sensitivity and specificity of predicting cognitive decline at follow-up time,” the researchers wrote.
About the Author
