Changes in the activity of the enzyme aromatic l-amino acid decarboxylase (AADC) can be assessed through a high-resolution imaging technology called FMT-PET, according to aa study from Sleep Medicine and reported on in AACD News. AADC plays a role in the production of the neurotransmitters dopamine and serotonin.

The study also showed that measuring changes in AADC activity in the brain by FMT-PET—an abbreviation for 6-fluoro-meta-tyrosine positron emission tomography—could help identify people with rapid eye movement (REM) sleep behavior disorder who are more likely to progress to Parkinson’s disease or related neurological disorders.

There were no obvious differences in FMT-PET readings at the baseline scan. However, individuals who progressed to develop neurological disorders had significantly lower scores on the second scan; that was evidence that AADC activity was decreasing over time in this group. This pattern was consistent across multiple regions of the brain.

“These results clarified that the process of dopamine synthesis in dopaminergic nerve terminals changed over time and suggest that FMT-PET may predict the risk of developing neurodegenerative diseases in patients with [RBD],” the researchers wrote.

Read more from AADC News and find the study in Sleep Medicine.