In-Uk Song

Parkinson’s disease (PD) is a prevalent neurodegenerative disorder caused by the loss of dopaminergic neurons, leading to motor deficits and non-motor symptoms. While current pharmacotherapies provide symptomatic relief, they fail to halt disease progression and often lead to complications like levodopa-induced dyskinesia (LID). Non-invasive brain stimulation offers a promising adjunct by modulating neural excitability. Repetitive transcranial magnetic stimulation (rTMS) improves motor function and gait when applied at high frequencies to the motor cortex, while low-frequency stimulation targets the supplementary motor area to alleviate LID. Transcranial direct current stimulation (tDCS) utilizes weak currents to enhance motor performance and cognition, though larger trials are needed to confirm its efficacy. The most advanced modality, low-intensity focused ultrasound (LIFU), provides millimeter-scale precision to target deep subcortical structures. It shows potential for neuroprotection and targeted drug delivery via transient blood-brain barrier opening. This review evaluates the mechanisms and clinical evidence for rTMS, tDCS, and LIFU, focusing on optimizing stimulation parameters for standardized clinical use in PD. Overcoming the limitations of traditional medicine, these technological advancements represent a significant frontier in restorative neurology.

Kim H, et al. J Korean Med Sci. 2026 Sep;41:e238. https://doi.org/10.3346/jkms.2026.41.e238

Kim BS, et al. J Brain Neuromodulation Ther. 2026 Jan;1(1):30-38. https://doi.org/10.66227/jbnt.2026.1.1.30

Background: Speech abnormalities are recognized as early indicators of Alzheimer's disease (AD) and mild cognitive impairment (MCI). Objective: To determine whether deep-learning models trained on mel-spectrograms of brief speech tasks can (i) discriminate individuals with MCI and AD from cognitively normal controls (NC) and (ii) estimate cognitive status with clinically useful accuracy. Methods: Speech from 594 participants (185 NC, 231 MCI, 178 AD) was recorded through a mobile application that included 11 cognitive-linguistic tasks. Audio was converted into mel-spectrogram images and processed using a VGG16-based deep-learning model with transfer learning and fine-tuning of block 5. Task-specific feature vectors were extracted, concatenated, and used to train a deep neural network. The dataset was split into training, validation, and test sets (3:1:1), and five-split cross-validation was performed. Results: The model demonstrated an overall accuracy of 72.4% in classifying NC from the abnormal group (MCI and AD), with sensitivity and specificity of 72.5% and 72.2%, respectively, a balanced accuracy of 72.4%, and an AUC of 0.997. In binary classifications, the model achieved 82.9% accuracy (balanced accuracy 82.9%, AUC 0.992) for NC versus AD, 70.7% accuracy (balanced accuracy 70.3%, AUC 0.956) for NC versus MCI, and 77.5% accuracy (balanced accuracy 78.9%, AUC 0.889) for MCI versus AD. Tasks such as serial subtraction, storytelling, and picture description contributed most to classification performance, indicating their effectiveness in capturing cognitive deficits. Conclusions: Mel-spectrogram-based deep-learning analysis of speech shows promise as a rapid, non-invasive, and language-independent screening tool for early cognitive impairment, with potential advantages over traditional assessments such as the Mini-Mental State Examination.

Neurodegenerative diseases, such as Alzheimer's disease (AD) and Parkinson's disease (PD), remain major challenges in clinical neurology, as no definitive cure exists. Non-invasive brain stimulation (NIBS) techniques, including repetitive transcranial magnetic stimulation (rTMS), transcranial direct current stimulation (tDCS), and low-intensity focused ultrasound (LIFU), have emerged as promising therapeutic approaches for modulating cortical excitability and promoting neuroplasticity. rTMS appears to promote synaptic plasticity and increase regional cerebral blood flow, which may contribute to improved memory and executive function. tDCS also has demonstrated potential in enhancing cognitive abilities in AD by modulating cortical excitability via weak direct currents. LIFU, a novel and less explored NIBS method, has shown promise in preclinical and early clinical studies for neurodegenerative diseases. Recent findings suggest that LIFU may enhance cognitive function, facilitate neuroplasticity, and temporarily open the blood-brain barrier to improve drug delivery in AD. In PD, NIBS techniques have been explored to alleviate motor symptoms and improve dopaminergic function. rTMS applied to the motor cortex and supplementary motor area has been associated with improved motor performance, while tDCS has shown potential for enhancing motor functions. LIFU is under investigation for its ability to modulate deep brain structures which plays a key role in PD pathophysiology. This review aims to analyze recent advancements in NIBS applications for AD and PD, highlighting their potential clinical benefits and future directions in neurodegenerative disease management.

Background and Purpose: Isolated cervical dystonia is characterized by sustained or intermittent neck movements caused by involuntary muscle contractions, resulting in abnormal movements or postures of cervical areas. We measured altered regional cerebral blood flow (rCBF) in patients with idiopathic cervical dystonia compared to healthy controls and explored the correlation between dystonia severity and rCBF patterns. Methods: A total of 38 patients with isolated cervical dystonia and 29 healthy controls were recruited. All subjects underwent Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) and Tc‐99m HMPAO SPECT; TWSTRS was used to assess the severity of dystonia. rCBF was compared between groups using voxel‐wise statistical analyses. Associations between rCBF in significant clusters and TWSTRS scores were examined using linear regression. Results: Compared with controls, patients with cervical dystonia exhibited reduced rCBF in brain regions implicated in sensory processing, motor control, and higher cognitive functions, including the left middle temporal gyrus, right postcentral gyrus, right lingual gyrus, left precuneus, right temporal pole, right middle cingulate gyrus, and right anterior cingulate gyrus. Although reduced rCBF was observed in seven regions, only the right temporal pole showed a significant correlation with TWSTRS motor scores. Reduced rCBF in the right temporal pole negatively correlated with higher TWSTRS scores in dystonia patients. Conclusion: The negative correlation between reduced rCBF in the right temporal pole and increased TWSTRS scores highlights a potential association between altered cerebral perfusion and dystonic symptom severity. Understanding these alterations could offer insights into the neurobiological basis of cervical dystonia, aiding targeted therapeutic interventions.

Background: Nicergoline is an ergoline derivative and vessel dilator that is used to treat cognitive deficits in cerebrovascular disease and various forms of dementia including vascular dementia (VaD). Although therapeutic effects of nicergoline have been established, little is known about its effects on cerebral perfusion in patients with VaD. We conducted this longitudinal study to evaluate the role of nicergoline in regional cerebral blood flow (rCBF) and cognitive function of VaD patients using technetium-99m ethyl cysteinate dimer single photon emission computed tomography (SPECT) and neuropsychological tests.Methods: Eleven VaD patients who received nicergoline therapy and 11 VaD patients who did not receive nicergoline therapy underwent SPECT and clinical neuropsychological tests at baseline and 6-month follow up visits. Patients treated with nicergoline received 30 mg twice per day. Clinical and cognitive functioning was assessed using the mini-mental state examination, clinical dementia rating with sum of boxes, Montreal cognitive assessment and neuropsychiatric inventory.Results: Nicergoline treatment showed improvement in the cognitive function via results of neuropsychological tests and neuropsychiatric symptoms, which were not statistically significant. In regard with change in rCBF, there also was no statistical significance between 2 groups.Conclusions: Although there is no significant improvement in cognitive function, numerical improvements were shown in cognitive tests other than rCBF. Larger, longitudinal studies are needed to further clarify the therapeutic effects of nicergoline and determine the utility of nicergoline for treatment of VaD.