Future of Tanscranial Magnetic Stimulation in Movement Disorders: Introduction of Novel Methods

RTMS of the Cerebellum Using an Accelerated Stimulation Protocol Improved Gait in Parkinson's Disease

BACKGROUND

Repetitive transcranial magnetic stimulation (rTMS) is a nonpharmacological and noninvasive brain stimulation technique that has been proven to be effective in Parkinson's disease (PD). The combination of rTMS and treadmill training improved gait function in PD greater than treadmill training alone.

OBJECTIVE

The aim of our study was to evaluate the combination of a novel high-intensity, short intervention rTMS treatment and a multimodal treatment protocol including of physiotherapy, occupational therapy and language therapy, the so-called Parkinson's Disease Multimodal Complex Treatment (PD-MCT), to improve motor function.

METHODS

In this randomized double-blind sham-controlled trial rTMS with 48 Hz or sham was applied over the cerebellum 3 times a day for 5 consecutive days. Patients were assessed at baseline (V0), after 5 days of treatment (V1), and 4 weeks later (V2). The primary clinical outcome measure was the motor sum-score of the Unified PD Rating Scale (UPDRSIII), secondary clinical outcomes were quantitative motor tasks.

RESULTS

A total of 36 PD patients were randomly allocated either to rTMS (n = 20) or sham (n = 16), both combined with PD-MCT. rTMS improved the UDPRSIII score comparing baseline and V1 in the treatment group by -8.2 points (P = .004). The 8MW and dynamic posturography remained unchanged in both groups after intervention. Conclusion. Compressing weeks of canonical rTMS protocols into 5 days was effective and well tolerated. rTMS may serve as an add-on therapy for augmenting the multimodal complex treatment of motor symptoms, but seems to be ineffective to treat postural instability.

Cortical mean diffusivity is reliable in measuring brain abnormalities in drug-naïve essential tremor patients

OBJECTIVE

Essential tremor (ET) is a common movement disorder, but the pathogenesis is poorly understood. Several associated brain areas were reported with inconsistent results due to heterogeneous populations. It is necessary to analyze a more homogeneous patient group.

METHODS

We recruited 25 drug-naïve ET patients and 36 age- and sex-matched controls. All participants were right-handed. ET. ET was defined according to diagnostic criteria of the Consensus Statement of the Movement Disorder Society on Tremor. ET patients were divided into sporadic (SET) and familial ET (FET). We assessed tremor severity in ET. The cortical microstructural changes were compared between ET patients and controls using mean diffusivity (MD) of diffusion tensor imaging, and cortical thickness. The correlation of tremor severity with the cortical MD and thickness were respectively analyzed.

RESULTS

MD values were increased in the insular, precuneus, medial orbitofrontal, posterior, and isthmus cingulate and temporo-occipital areas in ET. In comparison between SET and FET, MD values were higher in the superior and caudal middle frontal, postcentral, and temporo-occipital regions in FET. The cortical thickness of ET patients was more increased in the left lingual gyrus and lower in the right bankssts gyrus. We could not find any correlation of tremor severity with the MD values in ET patients. Still, there was a positive correlation with the cortical thickness of the frontal and parietal areas.

CONCLUSIONS

Our results support the idea that ET is a disorder that disrupts widespread brain regions and indicates that cortical MD may be more sensitive to measure brain abnormalities than cortical thickness.

Transcranial Magnetic Stimulation in the Treatment of Neurological Diseases

Transcranial Magnetic Stimulation (TMS) has widespread use in research and clinical application. For psychiatric applications, such as depression or OCD, repetitive TMS protocols (rTMS) are an established and globally applied treatment option. While promising, rTMS is not yet as common in treating neurological diseases, except for neurorehabilitation after (motor) stroke and neuropathic pain treatment. This may soon change. New clinical studies testing the potential of rTMS in various other neurological conditions appear at a rapid pace. This can prove challenging for both practitioners and clinical researchers. Although most of these neurological applications have not yet received the same level of scientific/empirical scrutiny as motor stroke and neuropathic pain, the results are encouraging, opening new doors for TMS in neurology. We here review the latest clinical evidence for rTMS in pioneering neurological applications including movement disorders, Alzheimer's disease/mild cognitive impairment, epilepsy, multiple sclerosis, and disorders of consciousness.

Neurotechnological Approaches to the Diagnosis and Treatment of Alzheimer’s Disease

Alzheimer’s disease (AD) is the most common cause of dementia in the elderly, clinically defined by progressive cognitive decline and pathologically, by brain atrophy, neuroinflammation, and accumulation of extracellular amyloid plaques and intracellular neurofibrillary tangles. Neurotechnological approaches, including optogenetics and deep brain stimulation, have exploded as new tools for not only the study of the brain but also for application in the treatment of neurological diseases. Here, we review the current state of AD therapeutics and recent advancements in both invasive and non-invasive neurotechnologies that can be used to ameliorate AD pathology, including neurostimulation via optogenetics, photobiomodulation, electrical stimulation, ultrasound stimulation, and magnetic neurostimulation, as well as nanotechnologies employing nanovectors, magnetic nanoparticles, and quantum dots. We also discuss the current challenges in developing these neurotechnological tools and the prospects for implementing them in the treatment of AD and other neurodegenerative diseases.

Tapping the Potential of Multimodal Non-invasive Brain Stimulation to Elucidate the Pathophysiology of Movement Disorders

This mini-review provides a detailed outline of studies that have used multimodal approaches in non-invasive brain stimulation to investigate the pathophysiology of the three common movement disorders, namely, essential tremor, Parkinson’s disease, and dystonia. Using specific search terms and filters in the PubMed^® database, we finally shortlisted 27 studies in total that were relevant to this review. While two-thirds (Brittain et al., 2013) of these studies were performed on Parkinson’s disease patients, we could find only three studies that were conducted in patients with essential tremor. We clearly show that although multimodal non-invasive brain stimulation holds immense potential in unraveling the physiological mechanisms that are disrupted in movement disorders, the technical challenges and pitfalls of combining these methods may hinder their widespread application by movement disorder specialists. A multidisciplinary team with clinical and technical expertise may be crucial in reaping the fullest benefits from such novel multimodal approaches.