In recent years, deep brain electrical stimulation (DBS) has become a primary treatment for
improving clinical symptoms in Parkinson's disease (PD) patients with predominantly motor
slowing after poor drug effects from conventional drug therapy medications or after the
progression of the disease. However, previous studies have been controversial in examining
whether DBS-STN promotes or impairs cognitive function in patients with PD. Previous studies
have found that DBS may affect executive function in patients with PD and that specific brain
regions are closely related to executive function. In this study, the investigators used
electroencephalograph-functional near-infrared spectroscopy (EEG-fNIRS) to obtain brain
network connectivity in subjects and to explore the possible relationship between executive
function and brain network connectivity in patients with Parkinson's disease. To explore the
possible brain network connectivity affecting execution in DBS-STN and to predict
postoperative executive function in PD patients in DBS.
Among the single cognitive domains impaired, executive function impairment is the most
common, accounting for more than 70% of the cases, and impairment of attention, working
memory, and visuospatial ability are also more common. Impaired executive function is the
most characteristic cognitive impairment in PD patients, which is related to the disruption
of the integrity of the frontal-striatal loops, designing a wide range of functional brain
regions, such as the frontal lobe, parietal lobe, cingulate gyrus, thalamus, substantia
nigra, and so on, and clinically manifested as impaired cognitive flexibility, planning,
concept formation, working memory, and learning ability. Executive dysfunction can seriously
affect patients' social behavior, especially when performing more complex tasks that require
the integration of multiple steps in a particular order.
Previous studies have found that brain network connectivity in specific brain regions is
closely related to cognitive function, for example, there have been many clinical studies
based on functional MRI blood oxygenation signals, but because of the poor immunity to
electromagnetic interference, patients with implanted electrodes have to be DBS-off in order
to do the MRI. Because of poor anti-motor interference, only some motor imagery and simple
finger movements can be acquired under the DBS-off condition for functional MRI, and
functional MRI has been an important issue limiting cognitive neuroscience research due to
its low temporal resolution and its inability to monitor in real-time the changes of cortical
brain blood oxygenation signals in the task paradigm.
Therefore, this study plans to design a multicenter, prospective, randomized,
parallel-controlled equipotent clinical trial, which innovatively combines
electroencephalography (EEG) with high temporal resolution and functional near-infrared
spectroscopy (fNIRS) with a high spatial resolution to monitor cortical oxygenation signals
in real-time, so that the brain electrophysiological and blood oxygenation signals can be
acquired in real-time during a test of executive function (Stroop/TMT). The real-time
measurement and evaluation of cognitive function by synchronously acquiring
electrophysiological and oxygenation signaling changes in the brain while the patient is
performing the executive function test (Stroop/TMT) and obtaining real-time EEG-fNIRS brain
network data during the executive function test has always been a higher-order field of
cognitive function research. The present study investigated the mechanisms of executive
function impairment in PD patients and whether DBS-STN affects the brain network mechanisms
of executive function. It is hoped to (1) quantify cognitive function and possible trends in
cognitive functioning in PD patients by EEG-fNIRS technique, (2) Explain whether there are
differences in executive function at the level of brain functional network connectivity
between surgical and conservative treatments and whether there are interaction effects of the
differences with the duration of treatment and the treatment modality as well as to analyze
their simple effects, (3) To minimize artificial confounders of short-term learning effects
and testers familiar with previous neurocognitive psychobehavioral tests, (4) To explore the
mechanism of DBS on the changes of cortical brain networks in PD patients, to avoid or reduce
the interference of surgery on cognitive functions, and to provide a theoretical basis for
treating personalized surgical plans.
In this study, the investigators planned to design a multicenter, prospective, randomized,
parallel-controlled clinical trial. A total of 80 patients were randomly assigned to the
DBS-STN group. The DBS treatment group, with the non-DBS treatment group, routinely DBS-on at
1 month postoperatively. The conservative treatment routinely on oral medication and the data
on patients' brain function was collected by the simultaneous EEG-fNIRS bimodal technique in
combination with cognitive testing (Stroop/TMT) at baseline, 1 month after DBS (DBS-on), and
at 6 months/12 months after DBS, respectively.