ACADEMIC RESEARCH IN MODERN SCIENCE
International scientific-online conference
58
LONG-TERM OUTCOMES OF DEEP BRAIN STIMULATION IN
PATIENTS WITH PARKINSON'S DISEASE
Uzakova Gulnoza Farkhodovna
Department of Neurology
Samarkand State Medical University
Shomurodova Dilnoza Salimovna
Department of Neurology
Samarkand State Medical University
https://doi.org/10.5281/zenodo.15301354
Abstract:
Deep Brain Stimulation (DBS) has established itself over the past
two decades as an effective method for comprehensive treatment of Parkinson's
disease when conservative therapy proves ineffective or insufficiently effective.
The method is based on the implantation of electrodes into specific brain
structures (predominantly the subthalamic nucleus, globus pallidus, or ventral
intermediate nucleus of the thalamus) with subsequent activation through a
subcutaneously implanted neurostimulator. Electrical stimulation modulates
pathological neuronal activity in the basal ganglia, which leads to a reduction in
the main motor symptoms of the disease and allows for a significant decrease in
the dosage of antiparkinsonian medications.
Keywords:
Parkinson's disease, deep brain stimulation, neurostimulation,
subthalamic nucleus, globus pallidus, long-term outcomes, long-term effects,
motor symptoms, non-motor manifestations, motor fluctuations, dyskinesias
Research Objective:
To evaluate the long-term neurological, cognitive, and
behavioral outcomes of deep brain stimulation of the subthalamic nucleus in
patients with Parkinson's disease at timepoints exceeding 2 years post-
implantation.
Materials and Methods:
The study included 48 patients with idiopathic
Parkinson's disease (PD) who underwent deep brain stimulation (DBS) surgery
between 2022 and 2025 at the neurosurgical department of the 1st
Multidisciplinary Clinic of Samarkand Medical University. The mean age of
patients was 61.2 ± 7.8 years, with disease duration of 11.6 ± 3.4 years. Patients
were divided into 2 groups: Group 1 (n=24): patients receiving active
neurostimulation for ≥3 years, without parameter changes for more than 6
months. Group 2 (n=24): patients requiring reprogramming or adjustment of
DBS, or with episodes of stimulation interruption due to technical or medical
reasons. Assessment was conducted using the following scales: UPDRS III —
motor symptoms, MoCA — cognitive function, BDI-II — depression level; PDQ-
39 — quality of life; L-dopa dependency level (in milligrams) was compared.
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Data analysis was performed using SPSS v.26.0. Statistical significance was
determined at p < 0.05.
Results:
Analysis of the obtained data showed significant differences
between groups of patients under different deep brain stimulation regimens
across various clinical and psychometric parameters. Motor functions (UPDRS
III scale): the mean UPDRS III score in Group 1 patients (with stable DBS
parameters) was 22.5 ± 3.1, indicating a relatively low level of motor deficit.
Meanwhile, in Group 2 patients (with episodes of stimulation disruption or
reprogramming needs), the mean score was significantly higher — 28.4 ± 4.8.
The differences between groups were statistically significant (p = 0.003),
demonstrating better control of motor symptoms with stable stimulation.
Cognitive functions (MoCA scale): the mean MoCA score in Group 1 patients was
25.1 ± 2.3, corresponding to normal cognitive functioning. In Group 2 patients,
this indicator was lower — 22.6 ± 3.0, indicating mild cognitive impairment. The
difference between groups was significant (p = 0.011), confirming the impact of
DBS regimen on cognitive status. Depression level (BDI-II scale): in the group
with stable stimulation, the mean depression score on the BDI-II scale was 9.2 ±
2.4, indicating the absence of clinically significant depression. Group 2 patients
showed a higher level of depressive symptoms — 13.6 ± 3.5, bordering on
moderate depression (p = 0.007). Quality of life (PDQ-39 scale): the total score
on the PDQ-39 questionnaire, reflecting subjective assessment of quality of life,
was 28.7 ± 5.2 in Group 1, whereas in Group 2 it was 36.3 ± 6.1. The difference
was significant (p = 0.009), indicating the negative impact of unstable
stimulation on patients' general well-being and daily activities. Daily levodopa
dose: patients with properly functioning DBS systems took an average of 410 ±
80 mg of levodopa daily, while patients from the second group required greater
medication support — 560 ± 90 mg/day. The differences were statistically
significant (p = 0.015), confirming reduced need for dopaminergic therapy with
effective neurostimulation. Group 1 patients demonstrated consistently better
motor and cognitive function, less severe depression, and better subjective
quality of life assessment. Repeated device adjustments and therapy
interruptions in Group 2 were associated with a higher risk of developing
dyskinesias, apathy, and cognitive decline.
Conclusions:
The obtained data convincingly demonstrate that stable and
properly configured deep brain stimulation contributes to better control of
motor disorders, reduces medication burden, and positively affects the cognitive
and emotional state of patients with Parkinson's disease. Conversely, unstable
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stimulation and technical failures are associated with deterioration in general
condition and reduced quality of life, highlighting the need for regular
neurophysiological monitoring and an interdisciplinary approach to treating
such patients.
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