Studies show that the benefits of sleep, a poorly understood phenomenon in which people with Parkinson’s disease wake up with fewer symptoms, are associated with higher levels of the dopamine transport protein in a region of the brain called the putamen. It has been.
These findings are meaningful because they “provide direct neurochemical evidence to explain SB. [sleep benefit] Phenomenon of PD [Parkinson’s disease] It’s a clinical observation first reported over 40 years ago,” the researchers wrote.
the study, “Sleep effects in Parkinson’s disease patients are associated with dopamine transporter expression in the putamenwas published in brain research.
The sleep effect is a phenomenon in which symptoms are alleviated when waking up.
Parkinson’s disease is caused by the death and dysfunction of nerve cells in the brain that make dopamine, a major chemical messenger involved in nerve cell communication. Levodopa and its derivatives, a mainstay of Parkinson’s disease treatment, basically work by giving the brain more substances to produce dopamine.
Sleep Benefits, which affects half of people diagnosed with Parkinson’s disease, is a phenomenon in which patients report less severe symptoms when they wake up after a full night’s sleep. The benefits of sleep have been a mystery to researchers because patients typically don’t have the drug in their systems after a full night’s sleep.
In some patients, this phenomenon may also occur after a nap.
To this day, the cause of the sleep effect remains a mystery, but previous studies have shown that Parkinson’s patients with longer disease duration, lower sleep efficiency, and greater motor impairment are more likely to experience the sleep effect. has been suggested. Sleep efficiency is the percentage of time spent asleep in bed.
Now, a team of researchers from the First Affiliated Hospital of Zhengzhou University in China has investigated whether brain levels of dopamine transporters (DATs), proteins that help control the release and reuptake of dopamine by neurons, are involved in this phenomenon. was evaluated.
The study included 115 people with Parkinson’s disease. A total of 61 patients (32 men, 29 women, mean age 60.3 years) experienced a sleep effect, while the remaining 54 (26 men, 28 women, mean age 61.9 years) did not. was.
The two groups were similar in terms of demographic factors such as age, gender, educational attainment and smoking history. Clinical measures of disease severity were also generally comparable.
This makes sense because it helps identify the patient. [sleep benefit] Improving the quality of sleep, rather than increasing the amount of medication, may relieve symptoms
However, significantly more patients in the sleep effect group reported tremor as their main symptom than those without the sleep effect. Equivalent daily dose (LEDD) was significantly lower in patients who experienced sleep effects.
Although most measures of sleep quality were not significantly different between the two groups, sleep-effective patients tended to regularly report higher sleep efficiency and longer sleep duration.
DAT levels were measured using positron emission tomography (PET). DAT-PET scans were successfully completed for 30 patients with sleep effect and her 26 patients without sleep effect. Results showed that DAT levels were significantly higher in several regions of the brain in patients who experienced sleep effects compared to those who did not.
Using these data, the researchers performed a multivariate statistical analysis, examining all data to look for factors significantly associated with sleep benefits.
After adjusting for potential influencing factors, they found that tremor-predominant Parkinson’s disease, lower LEDD, and longer sleep duration at night were significantly and independently associated with sleep benefits. .
Furthermore, higher DAT levels in the putamen, a brain region strongly affected by Parkinson’s disease, were significantly associated with sleep benefits.
These results suggest that the sleep effect in Parkinson’s disease patients is associated with DAT levels in the putamen. Since DAT helps regulate dopamine levels, the researchers speculate that brain cells with higher amounts of protein could better regulate dopamine signaling after sleep, which could lead to symptom relief. .
Findings may help identify patients whose symptoms may be relieved by sleep
To assess whether DAT levels can be used to predict whether a patient will benefit from sleep, researchers calculated the area under the receiver operating characteristic curve (AUC).
This is a statistical test that assesses how accurately a particular measure (in this case the DAT level) can determine the difference between two groups (whether or not they benefit from sleep). AUC values range from 0 to 1, with higher values indicating better discrimination.
The AUC using putamen DAT levels to discriminate between patients with and without sleep effects was as high as 0.916, suggesting that “putamen DAT expression levels can predict the SB phenomenon in PD patients.” the researcher writes.
“This makes sense because it helps identify patients with SB whose symptoms may be relieved by improving sleep quality rather than increasing dosage,” they added.
The team noted that the study was limited by its small size and emphasized that more studies are needed to validate these findings. He emphasized that the study relied on subjective patient reports, as there is no objective test that can determine whether a person is experiencing sleep effects.
“Future studies will also include collecting more data from more patients and establishing clear criteria for improvement in clinical symptoms in patients,” the team wrote.