Real-Time Precise Targeting of the Subthalamic Nucleus via Transfer Learning in a Rat Model of Parkinson's Disease Based on Microelectrode Arrays

In neurodegenerative disorders, neuronal firing patterns and oscillatory activity are remarkably altered in specific brain regions, which can serve as valuable biomarkers for the identification of deep brain regions. The subthalamic nucleus (STN) has been the primary target for DBS in patients with Parkinson's disease (PD). In this study, changes in the spike firing patterns and spectral power of local field potentials (LFPs) in the pre-STN (zona incerta, ZI) and post-STN (cerebral peduncle, cp) regions were investigated in PD rats, providing crucial evidence for the functional localization of the STN. Sixteen-channel microelectrode arrays (MEAs) with sites distributed at different depths and widths were utilized to record neuronal activities. The spikes in the STN exhibited higher firing rates than those in the ZI and cp. Furthermore, the LFP power in the delta band in the STN was the greatest, followed by that in the ZI, and was greater than that in the cp. Additionally, increased LFP power was observed in the beta bands in the STN. To identify the best performing classification model, we applied various convolutional neural networks (CNNs) based on transfer learning to analyze the recorded raw data, which were processed using the Gram matrix of the spikes and the fast Fourier transform of the LFPs. The best transfer learning model achieved an accuracy of 95.16%. After fusing the spike and LFP classification results, the time precision for processing the raw data reached 500 ms. The pretrained model, utilizing raw data, demonstrated the feasibility of employing transfer learning for training models on neural activity. This approach highlights the potential for functional localization within deep brain regions.

Effects of physiotherapy and home-based training in parkinsonian syndromes: protocol for a randomised controlled trial (MobilityAPP)

INTRODUCTION

Gait and mobility impairment are pivotal signs of parkinsonism, and they are particularly severe in atypical parkinsonian disorders including multiple system atrophy (MSA) and progressive supranuclear palsy (PSP). A pilot study demonstrated a significant improvement of gait in patients with MSA of parkinsonian type (MSA-P) after physiotherapy and matching home-based exercise, as reflected by sensor-based gait parameters. In this study, we aim to investigate whether a gait-focused physiotherapy (GPT) and matching home-based exercise lead to a greater improvement of gait performance compared with a standard physiotherapy/home-based exercise programme (standard physiotherapy, SPT).

METHODS AND ANALYSIS

This protocol was deployed to evaluate the effects of a GPT versus an active control undergoing SPT and matching home-based exercise with regard to laboratory gait parameters, physical activity measures and clinical scales in patients with Parkinson's disease (PD), MSA-P and PSP. The primary outcomes of the trial are sensor-based laboratory gait parameters, while the secondary outcome measures comprise real-world derived parameters, clinical rating scales and patient questionnaires. We aim to enrol 48 patients per disease group into this double-blind, randomised-controlled trial. The study starts with a 1 week wearable sensor-based monitoring of physical activity. After randomisation, patients undergo a 2 week daily inpatient physiotherapy, followed by 5 week matching unsupervised home-based training. A 1 week physical activity monitoring is repeated during the last week of intervention.

ETHICS AND DISSEMINATION

This study, registered as 'Mobility in Atypical Parkinsonism: a Trial of Physiotherapy (Mobility_APP)' at clinicaltrials.gov (NCT04608604), received ethics approval by local committees of the involved centres. The patient's recruitment takes place at the Movement Disorders Units of Innsbruck (Austria), Erlangen (Germany), Lausanne (Switzerland), Luxembourg (Luxembourg) and Bolzano (Italy). The data resulting from this project will be submitted to peer-reviewed journals, presented at international congresses and made publicly available at the end of the trial.

TRIAL REGISTRATION NUMBER

NCT04608604.

Towards Real-Time, Continuous Decoding of Gripping Force From Deep Brain Local Field Potentials

Lack of force information and longevity issues are impediments to the successful translation of brain-computer interface systems for prosthetic control from experimental settings to widespread clinical application. The ability to decode force using deep brain stimulation electrodes in the subthalamic nucleus (STN) of the basal ganglia provides an opportunity to address these limitations. This paper explores the use of various classes of algorithms (Wiener filter, Wiener-Cascade model, Kalman filter, and dynamic neural networks) and recommends the use of a Wiener-Cascade model for decoding force from STN. This recommendation is influenced by a combination of accuracy and practical considerations to enable real-time, continuous operation. This paper demonstrates an ability to decode a continuous signal (force) from the STN in real time, allowing the possibility of decoding more than two states from the brain at low latency.

Neurofeedback Control in Parkinsonian Patients Using Electrocorticography Signals Accessed Wirelessly With a Chronic, Fully Implanted Device

Parkinson's disease (PD) is characterized by motor symptoms such as rigidity and bradykinesia that prevent normal movement. Beta band oscillations (13-30 Hz) in neural local field potentials (LFPs) have been associated with these motor symptoms. Here, three PD patients implanted with a therapeutic deep brain neural stimulator that can also record and wirelessly stream neural data played a neurofeedback game where they modulated their beta band power from sensorimotor cortical areas. Patients' beta band power was streamed in real-time to update the position of a cursor that they tried to drive into a cued target. After playing the game for 1-2 hours each, all three patients exhibited above chance-level performance regardless of subcortical stimulation levels. This study, for the first time, demonstrates using an invasive neural recording system for at-home neurofeedback training. Future work will investigate chronic neurofeedback training as a potentially therapeutic tool for patients with neurological disorders.

Characterizing effects of subthalamic nucleus deep brain stimulation on methamphetamine-induced circling behavior in hemi-Parkinsonian rats

The unilateral 6-hydroxydopamine (6-OHDA) lesioned rat model is frequently used to study the effects of subthalamic nucleus (STN) deep brain stimulation (DBS) for the treatment of Parkinson's disease. However, systematic knowledge of the effects of DBS parameters on behavior in this animal model is lacking. The goal of this study was to characterize the effects of DBS on methamphetamine-induced circling in the unilateral 6-OHDA lesioned rat. DBS parameters tested include stimulation amplitude, stimulation frequency, methamphetamine dose, stimulation polarity, and anatomical location of the electrode. When an appropriate stimulation amplitude and dose of methamphetamine were applied, high-frequency stimulation (> 130 Hz), but not low frequency stimulation (< 10 Hz), reversed the bias in ipsilateral circling without inhibiting movement. This characteristic frequency tuning profile was only generated when at least one electrode used during bipolar stimulation was located within the STN. No difference was found between bipolar stimulation and monopolar stimulation when the most effective electrode contact was selected, indicating that monopolar stimulation could be used in future experiments. Methamphetamine-induced circling is a simple, reliable, and sensitive behavioral test and holds potential for high-throughput study of the effects of STN DBS in unilaterally lesioned rats.

Exercise alleviates Parkinsonism: clinical and laboratory evidence

The present review examines the putative benefits for individuals afflicted with Parkinsonism, whether in the clinical setting or in the animal laboratory, accruing from different exercise regimes. The tendency for patients with Parkinson's disease (PD) to express either normal or reduced exercise capacity appears regulated by factors such as fatigue, quality-of-life and disorder severity. The associations between physical exercise and risk for PD, the effects of exercise on idiopathic Parkinsonism and quality-of-life, the effects of exercise on animal laboratory models of Parkinsonism and dopamine (DA) loss following neurotoxic insults, and the effects of exercise on the DA precursor, L-Dopa, efficacy are examined. It would appear to be case that in view of the particular responsiveness of the dopaminergic neurons to exercise, the principle of 'use it or lose' may be of special applicability among PD patients.

[Rehabilitation in the elderly subject with Parkinson's disease]

In the elderly, the aging of the locomotor, cardiorespiratory, and sensory apparatus, the cognitive and psychic changes, and the interaction of several pathologies require adaptation of the rehabilitation techniques in Parkinson's disease. Rehabilitation should be initiated early and directed toward functional objectives defined by a pluridisciplinary team. To maintain movements is a fundamental aim and must take into account the tiredness of the old subject. Gymnic, active and passive techniques are proposed to preserve the posture, balance and walk. The prevention of falls is a major goal to avoid the risks of grabatisation and trauma. Multiple respiratory disorders are related to disturbances of swallowing and affect the deficiencies of voice and speech. The objectives of care are different if the patient presents a parkinsonan syndrome different from Parkinson's disease or if dementia is associated. The treatment by neurostimulation in old subjects also raises new questions for rehabilitation.

The effects of loading and unloading treadmill walking on balance, gait, fall risk, and daily function in Parkinsonism

Our study aims were: 1) to determine whether assisted weight bearing or additional weight bearing is more beneficial to the improvement of function and increased stability in gait and dynamic balance in patients with Parkinsonism, compared with matched controls (treadmill alone). Twenty-three men and women participants (M +/- SD = 74.5 +/- 9.7 yrs; Males = 19, Females = 4) with Parkinsonism were in the study. Participants staged at 1-7 (M +/- SD = 3.96 +/- 1.07) using the Hoehn & Yahr scale. All participants were tested before, after the intervention (within one week), and four weeks later on: 1) dynamic posturography, 2) Berg Balance scale, 3) United Parkinson's Disease Rating Scale (UPDRS), 4) biomechanical assessment of strength and range of motion, and 5) Gaitrite force sensitive gait mat. Group 1 (treadmill control group), received treadmill training with no loading or unloading. Group 2 (unweighted group), walked on the treadmill assisted by the Biodex Unweighing System at a 25% body weight reduction. Group 3 (weighted group), ambulated wearing a weighted scuba-diving belt, which increased their normal body weight by 5%. All subjects walked on the treadmill for 20 minutes per day for 3 days per week for 6 weeks. Improvements in dynamic posturography, falls during balance testing, Berg Balance, UPDRS (Motor Exam), and gait for all groups lead us to believe that neuromuscular regulation can be facilitated in all Parkinson's individuals no matter what treadmill intervention is employed.

[Diagnosis and treatment of parkinsonian syndrome]

Parkinsonian syndrome is a clinical diagnosis. The appropriate selection of the diagnostic and therapeutic regime and its continuous monitoring are tasks for the specialist. The observations of the familydoctor can provide important information when the clinical course does not develop as expected. For idiopathic parkinsonian syndrome a wide range of medicinal, surgical and physical treatments are available. Physiotherapeutic and, where indicated, ergotherapeutic measures should form a regular component of the prescribed treatment.

A walking support/evaluation machine for patients with parkinsonism

Various walk supporting systems have been devised and developed. However, they have not been designed for supporting or evaluating the gait of parkinsonian patients, and not much consideration has been given to gait disturbances of parkinsonian patients. In this study: (a) We prepared a tentative model of walk supporting and monitoring system in consideration of typical symptoms of parkinsonism. (b) We conducted gait rehabilitation in a parkinsonian patient using the walk supporting and monitoring system and confirmed (i) the occurrence of frozen gait during walking, (ii) brachybasia, (iii) the absence of anterior tilting of the posture, pulsion symptom, and festination, and (iv) occurrence of hesitation to start walking. Therefore, typical symptoms of parkinsonism can be detected by the use of this system. (c) The medical staff can evaluate the state of recovery of patients on the basis of the data obtained from this system and use them for purposes such as guidance of rehabilitation.

[Why do Parkinson patients fall? How can falls be prevented? Etiologic, therpeutic and preventive aspects]

Parkinsonian patients suffer often from falls. There are a lot of causes. Postural instability is an important risk factor for falls in Parkinson's disease. Referring to postural instability and falls the outcome of therapeutic measures using drugs is poor. An interdisciplinary therapeutic approach and general measures can help preventing falls in patients with Parkinson's syndrome.

A novel skilled-reaching impairment in paw supination on the "good" side of the hemi-Parkinson rat improved with rehabilitation

Parkinson's disease is characterized by tremor, rigidity, bradykinesia, and postural abnormalities ascribed to the loss of nigrostriatal dopamine (DA). Symptoms similar to the human condition can be produced in the rat by DA-depleting 6-hydroxydopamine injections made into the nigrostriatal system. After a unilateral lesion, the rat symptoms include sensory and motor impairments and turning biases reflecting motor abnormalities to the contralateral-to-depletion side of the body. In addition, a number of studies on skilled reaching report impairments in the use of the ipsilateral limb. It is suggested that the ipsilateral deficit is secondary to the contralateral motor impairments however. Here we re-examine how rats with unilateral DA depletion use their ipsilateral limb for skilled reaching for food. We provide the first description of an impairment on the ipsilateral-to-depletion side of the body of the rat and the first demonstration of amelioration of the defect using behavioral therapy. Video analysis of rats reaching for single pellets of food with the ipsilateral limb revealed that, although limb advancement and food grasping were normal, paw supination and food release to the mouth were impaired. Consequently, the animals were unable to transport a grasped food pellet to the mouth. Behavioral therapy, consisting of training in a simpler reaching task, strikingly lessened the impairment and improved reaching movements to the point that the rats could transport the food to the mouth. The results are discussed in relation to possible causes of the ipsilateral impairment, its treatment, and to relevant research on human Parkinson patients, indicating that they display bilateral improvements after unilateral treatments.

[Use of a bilateral stabilographic platform in the diagnosis and rehabilitation of movement disorders at the clinic of nervous system diseases]

The paper presents the results of the study whose aims were to reveal the specific features of vertical posture maintenance in patients with various motor disorders by using a computer stabilographic complex with a bilateral platform, to draw up computer rehabilitative programmes that take into account the detected features of posture stability disorders in these groups of patients, to evaluate the efficiency of use of programmes drawn up to train vertical posture stability in the rehabilitation of patients with motor disorders of various origin.

Work toward real-time control of a cortical neural prothesis

Implantable devices that interact directly with the human nervous system have been gaining acceptance in the field of medicine since the 1960's. More recently, as is noted by the FDA approval of a deep brain stimulator for movement disorders, interest has shifted toward direct communication with the central nervous system (CNS). Deep brain stimulation (DBS) can have a remarkable effect on the lives of those with certain types of disabilities such as Parkinson's disease, Essential Tremor, and dystonia. To correct for many of the motor impairments not treatable by DBS (e.g. quadriplegia), it would be desirable to extract from the CNS a control signal for movement. A direct interface with motor cortical neurons could provide an optimal signal for restoring movement. In order to accomplish this, a real-time conversion of simultaneously recorded neural activity to an online command for movement is required. A system has been established to isolate the cellular activity of a group of motor neurons and interpret their movement-related information with a minimal delay. The real-time interpretation of cortical activity on a millisecond time scale provides an integral first step in the development of a direct brain-computer interface (BCI).