Deep Brain Stimulation in Parkinson's Disease

Effects of transcranial magneto-acoustic stimulation on cognitive function and neural signal transmission in the hippocampal CA1 region of mice

As a new means of brain neuroregulation and research, transcranial magneto-acoustic stimulation (TMAS) uses the coupling effect of ultrasound and a static magnetic field to regulate neural activity in the corresponding brain areas. Calcium ions can promote the secretion of neurotransmitters and play a key role in the transmission of neural signals in brain cognition. In this study, to explore the effects of TMAS on cognitive function and neural signaling in the CA1 region of the hippocampus, TMAS was applied to male 2-month-old C57 mice with a magnetic field strength of 0.3 T and ultrasound intensity of 2.6 W/cm2. First, the efficiency of neural signaling in the CA1 region of the mouse hippocampus was detected by fiber photometry. Second, the effects of TMAS on cognitive function in mice were investigated through multiple behavioral experiments, including spatial learning and memory ability, anxiety and desire for novelty. The experimental results showed that TMAS could improve cognitive function in mice, and the efficiency of neural signaling in the CA1 area of the hippocampus was significantly increased during stimulation and maintained for one week after stimulation. In addition, the neural signaling efficiency in the CA1 area of the hippocampus increased in the open field (OF) experiment and recovered after one week, the neural signaling efficiency in the new object exploration (NOE) experiment was significantly enhanced, and the intensity slowed after one week. In conclusion, TMAS enhances cognitive performance and promotes neural signaling in the CA1 region of the mouse hippocampus.

Effects of subthalamic nucleus deep brain stimulation on the speech of Spanish-speaking Parkinson's disease patients during the first year of treatment

PURPOSE

To describe the effects of subthalamic nucleus deep brain stimulation (STN-DBS) on the speech of Spanish-speaking Parkinson's disease (PD) patients during the first year of treatment.

METHODS

The speech measures (SMs): maximum phonation time, acoustic voice measures, speech rate, speech intelligibility measures, and oral diadochokinesis rates of nine Colombian idiopathic PD patients (four females and five males; age = 63 ± 7 years; years of PD = 10 ± 7 years; UPDRS-III = 57 ± 6; H&Y = 2 ± 0.3) were studied in OFF and ON medication states before and every three months during the first year after STN-DBS surgery. Praat software and healthy native listeners' ratings were used for speech analysis. Statistical analysis tried to find significant differences in the SMs during follow-up (Friedman test) and between medication states (Wilcoxon paired test). Also, a pre-surgery variation interval (PSVI) of reference for every participant and SM was calculated to make an individual analysis of post-surgery variation.

RESULTS

Non-significative post-surgery or medication state-related differences in the SMs were found. Nevertheless, individually, based on PSVIs, the SMs exhibited: no variation, inconsistent or consistent variation during post-surgery follow-up in different combinations, depending on the medication state.

CONCLUSION

As a group, participants did not have a shared post-surgery pattern of change in any SM. Instead, based on PSVIs, the SMs varied differently in every participant, which suggests that in Spanish-speaking PD patients, the effects of STN-DBS on speech during the first year of treatment could be highly variable.

Gut-brain axis: A cutting-edge approach to target neurological disorders and potential synbiotic application

The microbiota-gut-brain axis (MGBA) represents a sophisticated communication network between the brain and the gut, involving immunological, endocrinological, and neural mediators. This bidirectional interaction is facilitated through the vagus nerve, sympathetic and parasympathetic fibers, and is regulated by the hypothalamic-pituitary-adrenal (HPA) axis. Evidence shows that alterations in gut microbiota composition, or dysbiosis, significantly impact neurological disorders (NDs) like anxiety, depression, autism, Parkinson's disease (PD), and Alzheimer's disease (AD). Dysbiosis can affect the central nervous system (CNS) via neuroinflammation and microglial activation, highlighting the importance of the microbiota-gut-brain axis (MGBA) in disease pathogenesis. The microbiota influences the immune system by modulating chemokines and cytokines, impacting neuronal health. Synbiotics have shown promise in treating NDs by enhancing cognitive function and reducing inflammation. The gut microbiota's role in producing neurotransmitters and neuroactive compounds, such as short-chain fatty acids (SCFAs), is critical for CNS homeostasis. Therapeutic interventions targeting the MGBA, including dietary modulation and synbiotic supplementation, offer potential benefits for managing neurodegenerative disorders. However, more in-depth clinical studies are necessary to fully understand and harness the therapeutic potential of the MGBA in neurological health and disease.

A Comprehensive Approach to Parkinson's Disease: Addressing Its Molecular, Clinical, and Therapeutic Aspects

Parkinson's disease (PD) is a gradually worsening neurodegenerative disorder affecting the nervous system, marked by a slow progression and varied symptoms. It is the second most common neurodegenerative disease, affecting over six million people in the world. Its multifactorial etiology includes environmental, genomic, and epigenetic factors. Clinical symptoms consist of non-motor and motor symptoms, with motor symptoms being the classic presentation. Therapeutic approaches encompass pharmacological, non-pharmacological, and surgical interventions. Traditional pharmacological treatment consists of administering drugs (MAOIs, DA, and levodopa), while emerging evidence explores the potential of antidiabetic agents for neuroprotection and gene therapy for attenuating parkinsonian symptoms. Non-pharmacological treatments, such as exercise, a calcium-rich diet, and adequate vitamin D supplementation, aim to slow disease progression and prevent complications. For those patients who have medically induced side effects and/or refractory symptoms, surgery is a therapeutic option. Deep brain stimulation is the primary surgical option, associated with motor symptom improvement. Levodopa/carbidopa intestinal gel infusion through percutaneous endoscopic gastrojejunostomy and a portable infusion pump succeeded in reducing "off" time, where non-motor and motor symptoms occur, and increasing "on" time. This article aims to address the general aspects of PD and to provide a comparative comprehensive review of the conventional and the latest therapeutic advancements and emerging treatments for PD. Nevertheless, further studies are required to optimize treatment and provide suitable alternatives.

Electrical stimulation of the cuneiform nucleus enhances the effects of rehabilitative training on locomotor recovery after incomplete spinal cord injury

Most human spinal cord injuries are anatomically incomplete, leaving some fibers still connecting the brain with the sublesional spinal cord. Spared descending fibers of the brainstem motor control system can be activated by deep brain stimulation (DBS) of the cuneiform nucleus (CnF), a subnucleus of the mesencephalic locomotor region (MLR). The MLR is an evolutionarily highly conserved structure which initiates and controls locomotion in all vertebrates. Acute electrical stimulation experiments in female adult rats with incomplete spinal cord injury conducted in our lab showed that CnF-DBS was able to re-establish a high degree of locomotion five weeks after injury, even in animals with initially very severe functional deficits and white matter lesions up to 80-95%. Here, we analyzed whether CnF-DBS can be used to support medium-intensity locomotor training and long-term recovery in rats with large but incomplete spinal cord injuries. Rats underwent rehabilitative training sessions three times per week in an enriched environment, either with or without CnF-DBS supported hindlimb stepping. After 4 weeks, animals that trained under CnF-DBS showed a higher level of locomotor performance than rats that trained comparable distances under non-stimulated conditions. The MLR does not project to the spinal cord directly; one of its main output targets is the gigantocellular reticular nucleus in the medulla oblongata. Long-term electrical stimulation of spared reticulospinal fibers after incomplete spinal cord injury via the CnF could enhance reticulospinal anatomical rearrangement and in this way lead to persistent improvement of motor function. By analyzing the spared, BDA-labeled giganto-spinal fibers we found that their gray matter arborization density after discontinuation of CnF-DBS enhanced training was lower in the lumbar L2 and L5 spinal cord in stimulated as compared to unstimulated animals, suggesting improved pruning with stimulation-enhanced training. An on-going clinical study in chronic paraplegic patients investigates the effects of CnF-DBS on locomotor capacity.

Nicotinic Acetylcholine Receptors in Glial Cells as Molecular Target for Parkinson's Disease

Parkinson's disease (PD) is a progressive neurodegenerative disease characterized by resting tremor, bradykinesia, rigidity, and postural instability that also includes non-motor symptoms such as mood dysregulation. Dopamine (DA) is the primary neurotransmitter involved in this disease, but cholinergic imbalance has also been implicated. Current intervention in PD is focused on replenishing central DA, which provides remarkable temporary symptomatic relief but does not address neuronal loss and the progression of the disease. It has been well established that neuronal nicotinic cholinergic receptors (nAChRs) can regulate DA release and that nicotine itself may have neuroprotective effects. Recent studies identified nAChRs in nonneuronal cell types, including glial cells, where they may regulate inflammatory responses. Given the crucial role of neuroinflammation in dopaminergic degeneration and the involvement of microglia and astrocytes in this response, glial nAChRs may provide a novel therapeutic target in the prevention and/or treatment of PD. In this review, following a brief discussion of PD, we focus on the role of glial cells and, specifically, their nAChRs in PD pathology and/or treatment.

Neurocognitive changes at different follow-up times after bilateral subthalamic nucleus deep brain stimulation in patients with Parkinson's disease

Background

Bilateral deep thalamic nucleus brain stimulation (STN-DBS) surgery is often used to treat the motor symptoms of patients with Parkinson's disease. The change of neurocognitive symptoms in patients is, however, still unclear.

Objective

We aimed at analyzing the deterioration of neurocognitive symptoms in patients with Parkinson's disease after deep brain stimulation surgery under different follow-up times.

Methods

A comprehensive literature review was conducted using Pubmed, Cochrane Library, and Web of Science to screen eligible study records, the meta-analysis was performed using an inverse variance method and a random-effects model. Additionally, the areas of analysis include five: cognition, executive function, memory capacity, and verbal fluency (phonetic fluency and semantic fluency). They were analyzed for changes at six and twelve months postoperatively compared to baseline. The Meta-analysis has been registered with PROSPERO under the registration number: CRD42022308786.

Results

In terms of overall cognitive performance, executive function, and memory capacity, the original studies show a trend of improvement in these areas at 12 months postoperatively compared with 6 months, at variance, patients did not improve or deteriorated in phonetic fluency(d = -0.42 at both 6-month and 12-month follow-up) and semantic fluency from 6 to 12 months postoperatively.

Conclusion

In terms of most neurocognitive symptoms, including cognitive ability, executive function, and learning memory capacity, bilateral STN-DBS surgery appears to be safe at relatively long follow-up times. However, postoperative phonetic and semantic fluency changes should still not be underestimated, and clinicians should pay more attention to patients' changes in both.

Spatial preference behavior of robo-pigeons induced by electrical stimulus targeting fear nuclei

BACKGROUND

Numerous studies have confirmed that stimulating the mid-brain motor nuclei can regulate movement forcibly for robo-pigeons, but research on behavior modulation using non-motor nuclei is scarce.

OBJECTIVE

In this study, we constructed a spatial preference behavior by stimulating the stratum griseum periventriculare (SGP), a nucleus correlated with fear and escape, for robo-pigeons.

METHODS

The study was carried out in a square-enclosed experimental field, with a designated box serving as the 'safe' area for the robo-pigeons. If the robo-pigeon exits this area, the SGP will be stimulated. After a brief training period, the robo-pigeons will have a clear spatial preference for the box.

RESULTS

The result from five pigeons has shown that, after simple training, the animals develop a spatial preference for the box. They can quickly return to the box in any situation when the SGP is stimulated, with a success rate exceeding 80% (89.0 ± 6.5%). Moreover, this behavior is highly stable and remains consistent, unaffected by changes in the location of the box or the interference box.

CONCLUSION

The results prove that using the electrical stimulus could enable animals to accomplish more complex tasks. It may offer a novel approach to regulating pigeon behavior and further advance the study of cyborg animals.

Application of OpenArray Technology to Assess Changes in the Expression of Functionally Significant Genes in the Substantia Nigra of Mice in a Model of Parkinson's Disease

Studying the molecular mechanisms of the pathogenesis of Parkinson's disease (PD) is critical to improve PD treatment. We used OpenArray technology to assess gene expression in the substantia nigra (SN) cells of mice in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) model of PD and in controls. Among the 11 housekeeping genes tested, Rps27a was taken as the reference gene due to its most stable expression in normal and experimental conditions. From 101 genes encoding functionally significant proteins of nigrostriatal dopaminergic neurons, 57 highly expressed genes were selected to assess their expressions in the PD model and in the controls. The expressions of Th, Ddc, Maoa, Comt, Slc6a3, Slc18a2, Drd2, and Nr4a2 decreased in the experiment compared to the control, indicating decreases in the synthesis, degradation, and transport of dopamine and the impaired autoregulation of dopaminergic neurons. The expressions of Tubb3, Map2, Syn1, Syt1, Rab7, Sod1, Cib1, Gpx1, Psmd4, Ubb, Usp47, and Ctsb genes were also decreased in the MPTP-treated mice, indicating impairments of axonal and vesicular transport and abnormal functioning of the antioxidant and ubiquitin-proteasome systems in the SN. The detected decreases in the expressions of Snca, Nsf, Dnm1l, and Keap1 may serve to reduce pathological protein aggregation, increase dopamine release in the striatum, prevent mitophagy, and restore the redox status of SN cells.

Temporal trends in neurosurgical volume and length of stay in a public healthcare system: A decade in review with a focus on the COVID-19 pandemic

Background

Over the past decade, neurosurgical interventions have experienced changes in operative frequency and postoperative length of stay (LOS), with the recent COVID-19 pandemic significantly impacting these metrics. Evaluating these trends in a tertiary National Health Service center provides insights into the impact of surgical practices and health policy on LOS and is essential for optimizing healthcare management decisions.

Methods

This was a single tertiary center retrospective case series analysis of neurosurgical procedures from 2012 to 2022. Factors including procedure type, admission urgency, and LOS were extracted from a prospectively maintained database. Six subspecialties were analyzed: Spine, Neuro-oncology, Skull base (SB), Functional, Cerebrospinal fluid (CSF), and Peripheral nerve (PN). Mann-Kendall temporal trend test and exploratory data analysis were performed.

Results

19,237 elective and day case operations were analyzed. Of the 6 sub-specialties, spine, neuro-oncology, SB, and CSF procedures all showed a significant trend toward decreasing frequency. A shift toward day case over elective procedures was evident, especially in spine (P < 0.001), SB (tau = 0.733, P = 0.0042), functional (tau = 0.156, P = 0.0016), and PN surgeries (P < 0.005). Over the last decade, decreasing LOS was observed for neuro-oncology (tau = -0.648, P = 0.0077), SB (tau = -0.382, P = 0.012), and functional operations, a trend which remained consistent during the COVID-19 pandemic (P = 0.01). Spine remained constant across the decade while PN demonstrated a trend toward increasing LOS.

Conclusion

Most subspecialties demonstrate a decreasing LOS coupled with a shift toward day case procedures, potentially attributable to improvements in surgical techniques, less invasive approaches, and increased pressure on beds. Setting up extra dedicated day case theaters could help deal with the backlog of procedures, particularly with regard to the impact of COVID-19.

Parkinson's disease, epilepsy, and amyotrophic lateral sclerosis-emerging role of AMPA and kainate subtypes of ionotropic glutamate receptors

Ionotropic glutamate receptors (iGluRs) mediate the majority of excitatory neurotransmission and are implicated in various neurological disorders. In this review, we discuss the role of the two fastest iGluRs subtypes, namely, α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and kainate receptors, in the pathogenesis and treatment of Parkinson's disease, epilepsy, and amyotrophic lateral sclerosis. Although both AMPA and kainate receptors represent promising therapeutic targets for the treatment of these diseases, many of their antagonists show adverse side effects. Further studies of factors affecting the selective subunit expression and trafficking of AMPA and kainate receptors, and a reasonable approach to their regulation by the recently identified novel compounds remain promising directions for pharmacological research.

Comparison of intraoperative imaging guided versus microelectrode recording guided deep brain stimulation for Parkinson's disease: A meta-analysis

BACKGROUND

Traditionally, most centers would use microelectrode recording (MER) to refine targeting in deep brain stimulation (DBS) surgery. In recent years, intraoperative imaging (IMG) guided DBS has become an alternative way to verify lead placement. Currently, there is still controversy surrounding the necessity of MER or IMG for DBS. This meta-analysis aims to explore lead accuracy, clinical efficacy and safety between IMG and MER guided DBS for Parkinson's disease (PD).

METHODS

PubMed, Embase, Web of Science, Cochrane Library were searched up to Mar, 2021 for studies reporting comparisons between IMG and MER guided DBS for PD. Subgroup analysis was conducted to assess effects of different IMG technology and DBS targeting site.

RESULTS

Six studies, comprising of 478 patients were included in our analysis. The mean difference between the two implantation techniques in stereotactic accuracy, lead passes per trajectory, improvement% of Unified Parkinson's Disease Rating Scale part III and levodopa equivalent daily dose were -0.45 (95% confidence interval, CI=-1.11 to 0.20), -0.18 (95% CI=-0.41 to 0.06), 3.40 (95% CI=-5.36 to 12.16), and 5.00 (95% CI=-1.40 to 11.39), respectively. No significant differences were observed in each adverse event and operation/procedure time between the two implantation techniques.

CONCLUSIONS

Both IMG and MER guided DBS offered effective control of motor symptoms for PD. Besides, IMG guided is comparable to MER guided DBS, in terms of safety, accuracy and efficiency. It is recommended for each hospital to select DBS guidance technology based on available resources and equipment.

Exploring CVD Method for Synthesizing Carbon-Carbon Composites as Materials to Contact with Nerve Tissue

The main purpose of these studies was to obtain carbon-carbon composites with a core built of carbon fibers and a matrix in the form of pyrolytic carbon (PyC), obtained by using the chemical vapor deposition (CVD) method with direct electrical heating of a bundle of carbon fibers as a potential electrode material for nerve tissue stimulation. The methods used for the synthesis of PyC proposed in this paper allow us, with the appropriate selection of parameters, to obtain reproducible composites in the form of rods with diameters of about 300 µm in 120 s (CF_PyC_120). To evaluate the materials, various methods such as scanning electron microscopy (SEM), scanning transmission electron microscope (STEM), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and tensiometer techniques were used to study their microstructural, structural, chemical composition, surface morphology, and surface wettability. Assessing their applicability for contact with nervous tissue cells, the evaluation of cytotoxicity and biocompatibility using the SH-SY5Y human neuroblastoma cell line was performed. Viability and cytotoxicity tests (WST-1 and LDH release) along with cell morphology examination demonstrated that the CF_PyC_120 composites showed high biocompatibility compared to the reference sample (Pt wire), and the best adhesion of cells to the surface among all tested materials.

Assessment of Knowledge and Perception Regarding Deep Brain Stimulation Among Medical Students in Saudi Arabia

BACKGROUND

 Deep brain stimulation (DBS) is a neurosurgical procedure approved for treating psychiatric and movement disorders, including Parkinson's disease (PD), essential tremor, dystonia, and other neurological conditions. The widespread use of DBS may not be reflected in the medical education curricula in Saudi universities, thus jeopardizing future patients' access to it. This study aims to investigate the knowledge and attitudes of medical students toward DBS as a therapeutic option.

METHOD

A descriptive cross-sectional questionnaire-based study was conducted. The survey was distributed on online platforms to acquire responses from different regions of Saudi Arabia. The target population was medical students in the preclinical and clinical phases of medical education from different regions of Saudi Arabia.

RESULTS

A total of 1075 medical students from various medical schools in Saudi Arabia were included. More than half of the students aged 21 to 23 (50.1%) were females (63.2%). More than half of the students have correctly recognized DBS as a Food and Drug Administration (FDA)-approved treatment (59.7%). Only 20.1% of the students stated that they received adequate education/training about DBS. About 53.8% of the students had self-rated their knowledge as poor, whereas 20.6% had rated their knowledge as good. A negative bias was more observed among the older students and students with a family history of DBS treatment. Half of the participants (54.1%) indicated that DBS is associated with severe adverse effects. A significant association between the level of knowledge about DBS and the academic level was observed.

CONCLUSION

Almost half of the medical students had poor knowledge and unfavorable attitude toward DBS in Saudi Arabia. The current medical curricula are incommensurable with the clinical implications of DBS, which may deny future patients from such an effective therapeutic option. We recommend incorporating DBS teaching sessions to enhance future physicians' awareness and understanding of the benefits of this intervention.

A protocol of a systematic review on deep brain stimulation surgery and its efficacy in addressing substance abuse addiction

Background

Pharmacotherapy and psychotherapeutic approaches are still the mainstay first line of treatment for substance use disorder. However, the path to rehabilitation and cessation of dependence often proves uncertain and laborious, with risks of relapse being considerable despite exposure to current therapeutic modalities. For cases of treatment-refractory addiction, deep brain stimulation (DBS) interventions can prove a more effective long term therapeutic solution for the patient.

Objectives

The aim of the study will be to systematically assess whether attempts at correcting substance use disorder via DBS neurosurgical interventions have been successful in inducing remission or ameliorating relapse rates.

Methods

The current study will analyze available literature from database inception up to 15th April 2023, reviewing all publications documenting results achieved with human patients undergoing DBS for substance use disorder in PubMed, Ovid, Cochrane, and Web of Science. The electronic database search will exclude animal studies in the field and focus solely on the application of DBS for the purposes of addressing addiction disorders.

Results

The expectation is for a reduced number of trial results to have been reported, namely due to the relatively recent application of DBS to address severe addiction. Nonetheless, numbers should be in sufficient amount to inform about the efficacy of the intervention.

Conclusion

This study will attempt to demonstrate the viability of DBS as a solution for tackling treatment-refractory substance use disorder, proposing it as a valid therapeutic option that can deliver robust results and help combat an expanding societal plague that is drug dependence.

Ultrasound deep brain stimulation decelerates telomere shortening in Alzheimer's disease and aging mice

Telomere length is a reliable biomarker for health and longevity prediction in both humans and animals. The common neuromodulation techniques, including deep brain stimulation (DBS) and optogenetics, have excellent spatial resolution and depth penetration but require implementation of electrodes or optical fibers. Therefore, it is important to develop methods for noninvasive modulation of telomere length. Herein, we reported on a new method for decelerating telomere shortening using noninvasive ultrasound deep brain stimulation (UDBS). Firstly, we found that UDBS could activate the telomerase-associated proteins in normal mice. Then, in the Alzheimer's disease mice, UDBS was observed to decelerate telomere shortening of the cortex and myocardial tissue and to effectively improve spatial learning and memory abilities. Similarly, UDBS was found to significantly slow down telomere shortening of the cortex and peripheral blood, and improve motor and cognitive functions in aging mice. Finally, transcriptome analysis revealed that UDBS upregulated the neuroactive ligand-receptor interaction pathway. Overall, the present findings established the critical role of UDBS in delaying telomere shortening and indicated that ultrasound modulation of telomere length may constitute an effective therapeutic strategy for aging and aging-related diseases.

Identification of Parkinson's disease-associated chromatin regulators

Parkinson's disease (PD) is a common neurological disorder that causes quiescent tremors, motor delays, depression, and sleep disturbances. Existing treatments can only improve symptoms, not stop progression or cure the disease, but effective treatments can significantly improve patients' quality of life. There is growing evidence that chromatin regulatory proteins (CRs) are involved in a variety of biological processes, including inflammation, apoptosis, autophagy, and proliferation. But the relationship of chromatin regulators in Parkinson's disease has not been studied. Therefore, we aim to investigate the role of CRs in the pathogenesis of Parkinson's disease. We collected 870 chromatin regulatory factors from previous studies and downloaded data on patients with PD from the GEO database. 64 differentially expressed genes were screened, the interaction network was constructed and the key genes with the top 20 scores were calculated. Then we discussed its correlation with the immune function of PD. Finally, we screened potential drugs and miRNAs. Five genes related to the immune function of PD, BANF1, PCGF5, WDR5, RYBP and BRD2, were obtained by using the absolute value of correlation greater than 0.4. And the disease prediction model showed good predictive efficiency. We also screened 10 related drugs and 12 related miRNAs, which provided a reference for the treatment of PD. BANF1, PCGF5, WDR5, RYBP and BRD2 are related to the immune process of Parkinson's disease and can predict the occurrence of Parkinson's disease, which is expected to become a new target for the diagnosis and treatment of Parkinson's disease.

Parkinson's disease research in Morocco: a review

Aim: To quantify and provide an overview on the scientific productivity made by Moroccan academics in the research on Parkinson's disease (PD) and parkinsonism. Materials & methods: Scientific articles, in either English or French, were gathered from published literature in three recognized databases: PubMed, ScienceDirect and Scopus. Results: We identified 95 published papers from which 39 articles have been extracted after removing inadequate publications and duplications between databases. All articles were published between 2006 and 2021. The selected articles were subdivided into five categories. Conclusion: The Moroccan academia is presently facing a low productivity issues and a lack of research laboratories focusing on PD research. We anticipate that providing more budgetary funds will significantly improve the productivity of PD research.

Promising biomarkers and therapeutic targets for the management of Parkinson's disease: recent advancements and contemporary research

Parkinson's disease (PD) is one of the progressive neurological diseases which affect around 10 million population worldwide. The clinical manifestation of motor symptoms in PD patients appears later when most dopaminergic neurons have degenerated. Thus, for better management of PD, the development of accurate biomarkers for the early prognosis of PD is imperative. The present work will discuss the potential biomarkers from various attributes covering biochemical, microRNA, and neuroimaging aspects (α-synuclein, DJ-1, UCH-L1, β-glucocerebrosidase, BDNF, etc.) for diagnosis, recent development in PD management, and major limitations with current and conventional anti-Parkinson therapy. This manuscript summarizes potential biomarkers and therapeutic targets, based on available preclinical and clinical evidence, for better management of PD.

Innovative Discoveries in Neurosurgical Treatment of Neurodegenerative Diseases: A Narrative Review

Neurodegenerative diseases (NDDs) encapsulate conditions in which neural cell populations are perpetually degraded and nervous system function destroyed. Generally linked to increased age, the proportion of patients diagnosed with a NDD is growing as human life expectancies rise. Traditional NDD therapies and surgical interventions have been limited. However, recent breakthroughs in understanding disease pathophysiology, improved drug delivery systems, and targeted pharmacologic agents have allowed innovative treatment approaches to treat NDDs. A common denominator for administering these new treatment options is the requirement for neurosurgical skills. In the present narrative review, we highlight exciting and novel preclinical and clinical discoveries being integrated into NDD care. We also discuss the traditional role of neurosurgery in managing these neurodegenerative conditions and emphasize the critical role of neurosurgery in effectuating these newly developed treatments.

Correlations between EEG and intestinal electrical stimulation

Many diseases affect the autonomous nervous system and the central nervous system simultaneously, for example Parkinson's disease or irritable bowel syndrome. To study neurophysiologic interactions between the intestinal electrical activity and the electroencephalography (EEG) pattern of the brain, we combined intestinal electrical stimulation (IES) and non-invasive telemetric full-band DC EEG recordings in an acute pig-model. Intestinal motility was monitored with accelerometers. Brain activity was analyzed with regard to network driven phenomena like phase amplitude coupling (PAC) within two time-windows: 1 min after IES (early response) and 3 min after stimulation (late response). Here we present the results for two stimulation sites (small intestine, colon) and two parietal scalp-EEG channels (right and left somatosensory cortex region). Electrical stimulation consisted of a 30 or 130 Hz pulse. In summary, the PAC modulation index at a parietal EEG recording position is decreased after IES. This effect is in line with an inhibitory effect of our IES protocol regarding peristalsis. The surprisingly strong effects of IES on network driven EEG patterns may be translated into new therapeutic techniques and/or diagnostic tools in the future. Furthermore, analytic tools, operating on sparse datasets, may be ideally suited for the integration in implantable intestinal pacemakers as feedback system.

Glycolysis: The Next Big Breakthrough in Parkinson's Disease

Parkinson's disease (PD) is a common neurodegenerative disease characterized by the death of dopaminergic neurons. Its pathogenesis comprises defects in the physiological pathway of mitophagy and mutations in the genes involved in this process's regulatory mechanism. PD manifests itself with multiple motor and non-motor symptoms, and currently, there are multiple pharmacological treatments, and unconventional non-drug treatments available. The mainstay of Parkinson's disease treatment has centered around directly manipulating neural mechanisms to retain high dopamine levels, either by exogenous administration, increasing intrinsic production, or inhibiting the breakdown of dopamine. In this review, we highlight a new potential biochemical modality of treatment, treating PD through glycolysis. We highlight how terazosin (TZ), via PGK1, increases ATP levels and how enhanced glycolysis serves a neuroprotective role in PD, and compensates for damage caused by mitophagy. We also discuss the role of quercetin, a bioactive flavonoid, in preventing the development of PD, and reversing mitochondrial dysfunction but only so in diabetic patients. Thus, further research should be conducted on glycolysis as a protective target in PD that can serve to not just prevent, but also alleviate the non-dopaminergic signs and symptoms of PD.

Interactions between gut microbiota and Parkinson's disease: The role of microbiota-derived amino acid metabolism

Non-motor symptoms (NMS) of Parkinson's disease (PD), such as constipation, sleep disorders, and olfactory deficits, may emerge up to 20 years earlier than motor symptoms. A series of evidence indicates that the pathology of PD may occur from the gastrointestinal tract to the brain. Numerous studies support that the gut microbiota communicates with the brain through the immune system, special amino acid metabolism, and the nervous system in PD. Recently, there is growing recognition that the gut microbiota plays a vital role in the modulation of multiple neurochemical pathways via the “gut microbiota-brain axis” (GMBA). Many gut microbiota metabolites, such as fatty acids, amino acids, and bile acids, convey signaling functions as they mediate the crosstalk between gut microbiota and host physiology. Amino acids' abundance and species alteration, including glutamate and tryptophan, may disturb the signaling transmission between nerve cells and disrupt the normal basal ganglia function in PD. Specific amino acids and their receptors are considered new potential targets for ameliorating PD. The present study aimed to systematically summarize all available evidence on the gut microbiota-derived amino acid metabolism alterations associated with PD.

Update on the application of mesenchymal stem cell-derived exosomes in the treatment of Parkinson's disease: A systematic review

Parkinson's disease (PD) has become the second largest neurodegenerative disease after Alzheimer's disease, and its incidence is increasing year by year. Traditional dopamine replacement therapy and deep brain stimulation can only alleviate the clinical symptoms of patients with PD but cannot cure the disease. In recent years, stem cell therapy has been used to treat neurodegenerative diseases. Many studies have shown that stem cell transplantation has a therapeutic effect on PD. Here, we review recent studies indicating that exosomes derived from mesenchymal stem cells also have the potential to treat PD in animal models, but the exact mechanism remains unclear. This article reviews the mechanisms through which exosomes are involved in intercellular information exchange, promote neuroprotection and freely cross the blood-brain barrier in the treatment of PD. The increase in the incidence of PD and the decline in the quality of life of patients with advanced PD have placed a heavy burden on patients, families and society. Therefore, innovative therapies for PD are urgently needed. Herein, we discuss the mechanisms underlying the effects of exosomes in PD, to provide new insights into the treatment of PD. The main purpose of this article is to explore the therapeutic potential of exosomes derived from mesenchymal stem cells and future research directions for this degenerative disease.

Deep Brain Stimulation in the Treatment of Parkinson’s Disease

Parkinson’s disease (PD) is a common progressive neurodegenerative movement disorder. The cardinal feature of Parkinson's is neuronal degeneration causing a dopamine deficit in the brain which leads to a host of clinical features in the patient. However, consensus over specific clinical criteria for diagnosis remains to be established. Parkinson’s does not have a cure yet, but a variety of diagnostic and treatment protocols have been developed over the years with a primary focus on pharmacological therapy. Anti-parkinsonian drugs such as levodopa lose their efficacy over time and are needed in higher doses as the disease inevitably progresses. An alternative to pharmacological therapy is deep brain stimulation (DBS). Deep brain stimulation involves transcranial placement of unilateral or bilateral leads (wires) most commonly in the sub-thalamic nucleus or the globus pallidus interna of the brain by stereotactic surgery. Given the multiple hypotheses explaining the different effects of DBS with sometimes conflicting mechanisms, it is difficult to pinpoint the exact way in which DBS operates. Nevertheless, it has proven to be significantly effective. DBS, although being a cost-effective treatment measure for Parkinson's patients, is not without limitations. A careful selection of patients is required preoperatively that determines the response and tolerance to the therapy in patients. This review aims to summarize the current literature on DBS in Parkinson's with a focus on the hypothesized mechanisms, selection criteria, advantages and its limitations.

Influence of Temporal Interference Stimulation Parameters on Point Neuron Excitability

Temporal interference (TI) stimulation is a technique in which two high frequency sinusoidal electric fields, oscillating at a slightly different frequency are sent into the brain. The goal is to achieve stimulation at the place where both fields interfere. This study uses a simplified version of the Hodgkin - Huxley model to analyse the different parameters of the TI-waveform and how the neuron reacts to this waveform. In this manner, the underlying mechanism of the reaction of the neuron to a TI -signal is investigated. Clinical relevance- This study shows the importance of the parameter choice of the temporal interference waveform and provides insights into the underlying mechanism of the neuronal response to a beating sine for the application of temporal interference stimulation.

New Understanding on the Pathophysiology and Treatment of Constipation in Parkinson’s Disease

Constipation, one of the most common prodromal non-motor symptoms of Parkinson’s disease (PD), usually occurs several years earlier than the onset of motor symptoms. Previous studies have shown that constipation occurrence increases as the disease progresses. However, the mechanism underlying this pathologic disorder is not clear yet. Moreover, chronic constipation causes slowness in gastric emptying and, therefore, may lead to a delay in the absorption of medications for PD, including levodopa and dopamine agonists. Accordingly, it is necessary to understand how the pathophysiological factors contribute to constipation during PD as well as pursue precise and effective treatment strategies. In this review, we encapsulate the molecular mechanism of constipation underlying PD and update the progress in the treatments of PD-associated constipation.

An Overview of Parkinson's Disease: Curcumin as a Possible Alternative Treatment

Parkinson's disease (PD) is a neurodegenerative disorder characterized by the loss of dopaminergic neurons in the substantia nigra of the midbrain and basal ganglia, followed by dopamine deficiency in the brain. Dopamine plays a crucial role in motor coordination, memory, and cognition; its decrease in PD leads to dyskinesia, cognitive deficits, and depression. In addition, the formation of alpha-synuclein protein aggregates (Lewy bodies) causes further damage to the CNS. Current treatment options include dopamine precursors, inhibitors of dopamine metabolism, upregulation of autophagy, adenosine A2A antagonists, and surgical intervention as a last resort. A challenge arises from a progressive decrease in treatment efficacy as the disease progresses and this necessitates exploration of adjunctive treatments. Epidemiological studies suggest that the prevalence of PD varies between ethnic groups of Caucasians, Asians, and African Americans. Notably, the prevalence of PD is lower in countries of Southeastern Asia including India. The differences in the diet of various ethnic groups may suggest an origin for this difference in the prevalence of PD. One staple ingredient in traditional Asian cuisine is turmeric. Curcuma longa, popularly known as turmeric, is an orange tuberous rhizome that has been used for centuries in traditional Indian cuisine and traditional medicine. Turmeric contains curcumin, a potent antioxidant that scavenges reactive oxygen species and chelates toxic metals. Curcumin has been proposed to be a neuroprotective agent due to its potent antioxidative properties. Though preliminary studies in animal model systems have suggested a protective effect of curcumin on dopaminergic neurons, the direct benefits of curcumin on the progress of PD remains poorly understood. In this review, we explore the promising use of curcumin as an adjunct to conventional PD treatments in order to enhance treatment and improve outcomes.

Deep Brain Stimulation and Treatment Outcomes of Young- and Late-Onset (≤55 Years) Parkinson's Disease: A Population-Based Study

Background: No studies have reported the rate of motor complications (MC) and response to medical and surgical treatment in a population-based cohort of young-onset Parkinson's Disease (YOPD) patients and a cohort of sex-matched late-onset Parkinson's Disease (LOPD).

Objective: To assess the outcomes of dopaminergic treatment in YOPD and LOPD, explore treatment-induced MC, medical adjustment, and rate of deep brain stimulation (DBS).

Methods: We used the expanded Rochester Epidemiology Project (eREP) to investigate a population-based cohort of YOPD between 2010 and 2015 in 7 counties in Minnesota. Cases with onset ≤55 years of age were included as YOPD. An additional sex-matched cohort of LOPD (onset at ≥56 years of age) was included for comparison. All medical records were reviewed to confirm the diagnoses.

Results: In the seven counties 2010–15, there were 28 YOPD patients, which were matched with a LOPD cohort. Sixteen (57%) YOPD had MC, as compared to 9 (32%) LOPD. In YOPD, 9 had motor fluctuations (MF) and Levodopa-induced dyskinesia (LID) together, whereas 3 had LID only and 4 MF only. In LOPD, 3 had MF and LID, 3 MF only, and 3 LID only. Following medical treatment for MC, 6/16 YOPD (38%) and 3/9 (33%) LOPD had symptoms resolution. In YOPD, 11/16 (69%) were considered for DBS implantation, in LOPD they were 2/9 (22%), but only 7 (6 YOPD and 1 LOPD) underwent the procedure. YOPD had significantly higher rates in both DBS candidacy and DBS surgery (respectively, p = 0.03 and p = 0.04). Among DBS-YOPD, 5/6 (83%) had positive motor response to the surgery; the LOPD case had a poor response. We report the population-based incidence of both YOPD with motor complications and YOPD undergoing DBS, which were 1.17 and 0.44 cases per 100,000 person-years, respectively.

Conclusion: Fifty-seven percent of our YOPD patients and 32% of the LOPD had motor complications. Roughly half of both YOPD and LOPD were treatment resistant. YOPD had higher rates of DBS candidacy and surgery. Six YOPD and 1 LOPD underwent DBS implantation and most of them had a positive motor response after the surgery.

Stimulation and transient inactivation of ventral tegmental area modify reinstatement of acquisition phase of morphine-induced conditioned place preference in male rats

For processing the development of psychological dependency, opioid reinforcement, and opiate-related associative reward, learning, and memory in the brain, the ventral tegmental area (VTA) is considered the key zone. As the responsible region for the morphine role in conditioned place preference (CPP), this area has an important role. So, the present research was conducted to investigate the effects of different intensities of electrical stimulation on VTA utilizing CPP, with two morphine doses. Reversible inactivation of VTA was performed via bilateral microinjection of Lidocaine into this area with two implanted separate cannulas. Our findings indicated that 5 mg/kg morphine-induced CPP was suppressed by 150 μA VTA electrical stimulation. The results also showed that bilateral Intra-VTA administration of Lidocaine significantly decreased the 5 mg/kg morphine-induced CPP acquisition phase in comparison with their respective sham group, which reversed in the reinstatement test. It should be concluded that these findings are important for the detection of mesolimbic nervous system ties and could help to find new ways to attenuate the rewarding action of morphine.

Perceptions and meanings of living with Parkinson's disease: an account of caregivers lived experiences

Purpose: Current study looked into caregiving process of those dealing with family members suffering from Parkinson’s disease, within the changing social milieu in India. It aimed to understand the experiential and existential impact on the lifeworld of caregivers.

Method: Narrative interviews of 10 female caregivers referred by neurologists were gathered. Employing Existential Phenomenological Analysis, the caregiver experiences were understood phenomenologically within an existential framework, six themes were generated.

Results: Themes were – Becoming a caregiver: Undertaking immeasurable and unrelenting responsibilities; Rising patient-hood of one’s family member: pain of losing the person in the patient; Experience of altered temporality: living in pain with the uncertainty and duration of the disease; Encountering meaninglessness: dwindling faith in principles of life; Existing as a “Being For” and not “Being With”: a caregiver’s self-estrangement and blurring of Identity and lastly Self-Preservation through brief moments of respite: coping with caregiving.

Conclusion: The study illuminated how caregiving is experienced by an individual at a process and psychic level by shedding light on the conflicts, concerns and exhaustions endured by them. Adopting an existential approach in healthcare setups can aid in moving closer to felt experiences of these caregivers and in developing integrative and meaningful interventions for enhancing their well-being.

Interleaved Stimulation for Freezing of Gait in Advanced Parkinson's Disease

Background

Freezing of gait (FOG) is a disabling and refractory symptom of advanced Parkinson's disease (PD). Interleaved stimulation (ILS) is a novel paradigm which may benefit axial symptoms of PD.

Objectives

To assess the effect of ILS on FOG in patients unresponsive to conventional subthalamic nucleus (STN) stimulation.

Methods

19 PD patients receiving subthalamic stimulation and experiencing FOG at both conventional (130-150Hz) and low frequency (60Hz) stimulation were given ILS.The primary outcome measure was the UPDRS part III gait score (item 29) at 3 months after ILS. A subset of patients was tested with the stand-walk-sit (SWS) test, 30 min after ILS.

Results

The mean UPDRS part III gait score (baseline: 1.8 ± 0.6) improved at 30 min (1.1 ± 0.8, P = 0.017) and remained improved at 3 months (1.2 ± 0.8, P = 0.048). FOG episodes reduced during SWS test (P = 0.041).

Conclusions

ILS of STN through two adjacent contacts provided significant short-term beneficial effects on FOG.

Parameters for subthalamic deep brain stimulation in patients with dystonia: a systematic review

BACKGROUND AND OBJECTIVE

Deep brain stimulation (DBS) is used for treating dystonia, commonly targeting the subthalamic nucleus (STN). Optimal stimulation parameters are required to achieve satisfying results. However, recommended parameters for STN-DBS remain to be identified. In this review, we aimed to assess the optimal stimulation parameters by analyzing previously published STN-DBS data of patients with dystonia.

METHODS

We examined the STN-DBS stimulation parameters used in studies on dystonia selected on the PubMed/Medline database.

RESULTS

Of the 86 publications retrieved from the PubMed/Medline database, we included 24, which consisted of data from 94 patients and 160 electrodes. Overall, the following average stimulation parameters were observed: amplitude, 2.59 ± 0.67 V; pulse width, 83.87 ± 34.70 μs; frequency, 142.08 ± 37.81 Hz. The average improvement rate was 64.72 ± 24.74%. The improvement rate and stimulation parameters were linearly dependent. The average improvement rate increased by 3.58% at each 10-Hz increase in frequency. In focal and segmental dystonia, the improvement rate and stimulation parameters were linearly dependent. The improvement rate increased by 6.06% and decreased by 2.14% at each 10-Hz increase in frequency and pulse width, respectively. Seventeen publications (83 patients) mentioned stimulation-related adverse effects, including dyskinesia (17), depression (8), transient dysarthria (5), weight gain (4), transient dysphasia (3), transient paresthesia (2), and sustained hyperkinesia (2).

CONCLUSIONS

The optimal stimulation parameter for STN-DBS varies across patients. Our findings may be useful for DBS programming based on the specific dystonia subtypes, especially for patients with focal and segmental dystonia.

Age-dependent efficacy of subthalamic nucleus deep brain stimulation in young- and late-onset Parkinson's disease based on a 10 year follow-up

INTRODUCTION

Long-term efficacy and safety of subthalamic nucleus deep brain stimulation (STN DBS) in patients with young-onset Parkinson's disease (YOPD) and late-onset PD (LOPD) (i.e. motor symptom initial appearance at ages ≤40 and > 40 years, respectively) was compared to identify relationships between PD onset age and the efficacy of DBS.

METHODS

Statistical analyses compared specific motor and non-motor features among 13 patients with YOPD and 11 with LOPD. Medication reduction patterns and dyskinesia severity scores at baseline and after 1, 3, 5, and 10 years of follow-up were also analyzed using a repeated measures ANOVA tests. Lastly, a correlation analysis identified relationships between the impact of DBS settings (volume of activated tissue) and levodopa equivalent daily dose (LED), dyskinesia severity scores, Unified Parkinson's Disease Rating Scale (UPDRS) part III, and UPDRS part II (disability) scores.

RESULTS

Ten years after DBS surgery, the reduction of LED from baseline (85.9 ± 592.6 mg versus 623.2 ± 464.9 mg; p = .023) and levodopa-induced dyskinesia (LID) scores (Unified Dyskinesia Rating Scale [UDysRS] parts III items 16-22; 1.6 ± 2.8 versus 5.5 ± 4.1; p = .013) were significantly lower in YOPD patients than LOPD patients. There were no significant differences between the two groups regarding UPDRS part III score improvement in response to levodopa, psychosis occurrence, or adverse effects.

CONCLUSION

Ten years after STN DBS surgery, LOPD patients showed greater LED reduction, and YOPD patients showed greater LID improvement, although the general long-term outcomes were similar between YOPD and LOPD patients.

A Case-Controlled Pilot Study on Rhythmic Auditory Stimulation-Assisted Gait Training and Conventional Physiotherapy in Patients With Parkinson's Disease Submitted to Deep Brain Stimulation

Deep brain stimulation (DBS) is indicated when motor disturbances in patients with idiopathic Parkinson's disease (PD) are refractory to current treatment options and significantly impair quality of life. However, post–DBS rehabilitation is essential, with particular regard to gait. Rhythmic auditory stimulation (RAS)-assisted treadmill gait rehabilitation within conventional physiotherapy program plays a major role in gait recovery. We explored the effects of a monthly RAS–assisted treadmill training within a conventional physiotherapy program on gait performance and gait-related EEG dynamics (while walking on the RAS–aided treadmill) in PD patients with (n = 10) and without DBS (n = 10). Patients with DBS achieved superior results than those without DBS concerning gait velocity, overall motor performance, and the timed velocity and self-confidence in balance, sit-to-stand (and vice versa) and walking, whereas both groups improved in dynamic and static balance, overall cognitive performance, and the fear of falling. The difference in motor outcomes between the two groups was paralleled by a stronger remodulation of gait cycle–related beta oscillations in patients with DBS as compared to those without DBS. Our work suggests that RAS-assisted gait training plus conventional physiotherapy is a useful strategy to improve gait performance in PD patients with and without DBS. Interestingly, patients with DBS may benefit more from this approach owing to a more focused and dynamic re–configuration of sensorimotor network beta oscillations related to gait secondary to the association between RAS-treadmill, conventional physiotherapy, and DBS. Actually, the coupling of these approaches may help restoring a residually altered beta–band response profile despite DBS intervention, thus better tailoring the gait rehabilitation of these PD patients.