Clinical Studies and Results
Non-Invasive Techniques:
a) Transcranial Magnetic Stimulation (TMS)
Several clinical studies have explored the efficacy of TMS in PD
treatment. A recent meta-analysis by [31] investigated the impact of
repetitive TMS (rTMS) on motor symptoms in PD patients. The analysis
included 34 randomized controlled trials with a total of 1,092
participants. The results indicated that high-frequency rTMS applied to
the primary motor cortex or supplementary motor area significantly
improved motor symptoms, as assessed by the Unified Parkinson’s Disease
Rating Scale (UPDRS) motor scores. Moreover, some studies have reported
positive effects of TMS on non-motor symptoms, such as cognitive
function and mood [35].
Despite these promising results, the optimal stimulation parameters and
treatment duration for TMS in PD patients remain to be established.
Furthermore, TMS may cause mild discomfort or pain at the stimulation
site and is contraindicated in patients with a history of seizures or
implanted metal devices [32].
b) Transcranial Direct Current Stimulation (tDCS)
tDCS has also been the subject of several clinical studies in PD
treatment. A systematic review and meta-analysis by [34] evaluated
the effects of tDCS on motor and non-motor symptoms in PD patients. The
analysis included 20 studies involving 536 participants. The results
suggested that anodal tDCS applied to the primary motor cortex led to
significant improvements in gait, balance, and cognitive function.
However, the authors noted that the heterogeneity of stimulation
parameters and treatment duration across studies warrants further
investigation to determine the optimal tDCS protocol for PD patients.
Potential side effects of tDCS include skin irritation and discomfort at
the stimulation site. In addition, the long-term effects of tDCS in PD
treatment need to be further explored [36].
Minimally Invasive Techniques:
a) Vagus Nerve Stimulation (VNS)
Preliminary clinical studies have investigated the potential benefits of
VNS in PD treatment. A pilot study by [37] assessed the safety and
efficacy of VNS in 17 PD patients with motor fluctuations. After six
months of treatment, participants experienced significant improvements
in their UPDRS motor scores, as well as in non-motor symptoms, such as
sleep and mood. The authors concluded that VNS could be a promising
adjunctive therapy for PD patients who do not respond adequately to
pharmacological treatments. However, larger-scale, randomized controlled
trials are needed to confirm these findings and determine the optimal
stimulation parameters for VNS in PD treatment [38].
b) Trigeminal Nerve Stimulation (TNS)
Clinical research on TNS for PD treatment is still in its early stages.
A pilot study by [39] evaluated the safety and efficacy of external
TNS (eTNS) in 12 PD patients with motor and non-motor symptoms. After 12
weeks of treatment, participants showed significant improvements in
their UPDRS motor scores, as well as in sleep quality and cognitive
function. The authors suggested that eTNS could be a promising
non-pharmacological treatment for PD, but larger and longer-term studies
are required to confirm its efficacy and safety.
In conclusion, next-generation cranial nerve stimulation and
neuromodulation techniques have shown promising results in clinical
studies, suggesting potential advantages over traditional
pharmacological and surgical treatments for PD. However, further
research is needed to establish the optimal stimulation parameters,
treatment duration, and long-term effects of these innovative
approaches, as well as to identify the patient populations that may
benefit the most from these therapies.