A phase 4, open-label study to evaluate the safety and immunogenicity of DTaP5-HBV-IPV-Hib in children previously vaccinated with DTaP2-HBV-IPV-Hib or DTaP5-HBV-IPV-Hib (V419-016)

DTaP5-HBV-IPV-Hib (Vaxelis®) is a hexavalent combination vaccine (HV) indicated in infants and toddlers for the prevention of diphtheria, tetanus, pertussis, hepatitis B, poliomyelitis, and invasive disease due to Haemophilus influenzae type b. Switching between HVs during the childhood vaccination series is sometimes necessary due to, for example, vaccine availability, health-care provider preference, and/or tender awards. The purpose of this study was to describe the safety, tolerability, and immunogenicity of a booster dose of Vaxelis® in participants who previously received a primary infant series of either DTaP2-HBV-IPV-Hib (Hexyon®) or Vaxelis®. Healthy participants approximately 11-13 months of age who previously received a two-dose primary series of Hexyon® (HHV group) or Vaxelis® (VVV group) all received a Vaxelis® booster dose. Immunogenicity was evaluated by measuring antibody levels to individual vaccine antigens approximately 30 days following booster vaccination. Safety was evaluated as the proportion of participants with adverse events (AEs). The proportions of participants with antibody-specific responses for antigens contained in both Vaxelis® and Hexyon® at 30 days post-toddler-booster vaccination with Vaxelis® were comparable between groups, and higher in the VVV group for Vaxelis® antigens PRN and FIM2/3. The overall proportions of participants with AEs were generally comparable between groups. Following a booster dose of Vaxelis®, immune responses were comparable between groups for all shared antigens, and higher in the VVV group for antigens found only in Vaxelis®. The booster was well tolerated in both groups. These data support the use of Vaxelis® as a booster in mixed HV regimens.

Objective assessment of the effects of opicapone in Parkinson's disease through kinematic analysis

BACKGROUND

Opicapone (OPC) is a third-generation, selective peripheral COMT inhibitor that improves peripheral L-DOPA bioavailability and reduces OFF time and end-of-dose motor fluctuations in Parkinson's disease (PD) patients.

OBJECTIVES

In this study, we objectively assessed the effects of adding OPC to L-DOPA on bradykinesia in PD through kinematic analysis of finger movements.

METHODS

We enrolled 20 treated patients with PD and motor fluctuations. Patients underwent two experimental sessions (L-DOPA, L-DOPA + OPC), separated by at least 1 week. In each session, patients were clinically evaluated and underwent kinematic movement analysis of repetitive finger movements at four time points: (i) before their usual morning dose of L-DOPA (T0), (ii) 30 min (T1), (iii) 1 h and 30 min (T2), and (iv) 3 h and 30 min after the L-DOPA intake (T3).

RESULTS

Movement velocity and amplitude of finger movements were higher in PD patients during the session with OPC compared to the session without OPC at all the time points tested. Importantly, the variability of finger movement velocity and amplitude across T0-T3 was significantly lower in the L-DOPA + OPC than L-DOPA session.

CONCLUSIONS

This study is the first objective assessment of the effects of adding OPC to L-DOPA on bradykinesia in patients with PD and motor fluctuations. OPC, in addition to the standard dopaminergic therapy, leads to significant improvements in bradykinesia during clinically relevant periods associated with peripheral L-DOPA dynamics, i.e., the OFF state in the morning, delayed-ON, and wearing-OFF periods.

Effectiveness of near-infrared spectroscopy to predict the chemical composition of feces and total-tract apparent nutrients digestibility estimated with uNDF or AIA in lactating buffaloes' feces

Following a comparison of nutrient total-tract digestibility estimates in lactating buffaloes using single-point undigestible NDF (uNDF) or acid-insoluble ash (AIA) as internal markers, the potential of fecal near-infrared spectroscopy (NIRS) to provide calibration equations for the assessment of the chemical composition of feces and nutrient total-tract digestibility estimated with internal markers was explored. Chemical analyses were performed on 147 fecal samples from lactating buffaloes reared in 5 farms in central Italy (Naples). Each farm fed a silage-based total mixed ration (TMR) to the buffaloes, which was sampled in the 2 d before the fecal collection. The TMR and individual fecal samples were collected and analyzed for dry matter (DM), organic matter (OM), ash, AIA, ether extract (EE), starch, fiber fractions (aNDFom, aNDF, ADFom, ADF, hemicellulose, cellulose, ADL, uNDF), N, CP and CP bound to aNDF (NDICP) and to ADF (ADICP). The uNDF content was determined through a 240-h in vitro fermentation and employed, together with AIA as markers to estimate the total-tract apparent digestibility (ttaDe) and total-tract digestibility (ttDe) of DM, OM, ash, N, CP, EE, aNDFom, aNDF, NDIP, ADFom and ADF, ADIN, ADL, hemicellulose, cellulose, starch, non-fibrous carbohydrates (NFC) and fraction B3 of N. No correlation was found between DM and OM digestibility estimated with AIA and uNDF as internal markers. Weak correlations were detected for all the other nutients digestibilities while strong correlations were observed for EE, ADFom, HC, NDIN, ADIN, NB3, NFC and starch.Inizio modulo The sample set (n = 147) was divided in a calibration set (n = 111) and a validation set (n = 36) to "train" and "validate" the fecal NIRS curve through an external validation process. An estimation usable for preliminary or initial evaluation was obtained for N, CP and aNDF fecal content. An excellent prediction was obtained for ttADINDe (R2 = 0.90) when estimated with uNDF as internal marker. The NIRS technology was not able to accurately predict all the other traits and the estimated nutrient digestibility of lactating buffalo diets from fecal spectra.

Using a food web model to predict the effects of Hazardous and Noxious Substances (HNS) accidental spills on deep-sea hydrothermal vents from the Mid-Atlantic Ridge (MAR) region

Deep-sea hydrothermal vents host unique ecosystems but face risks of incidents with Hazardous and Noxious Substances (HNS) along busy shipping lanes such as the transatlantic route. We developed an Ecopath with Ecosim (EwE) model of the Menez Gwen (MG) vent field (MG-EwE) (Mid-Atlantic Ridge) to simulate ecosystem effects of potential accidental spills of four different HNS, using a semi-Lagrangian Dispersion Model (sLDM) coupled with the Regional Ocean Modelling System (ROMS) calibrated for the study area. Food web modelling revealed a simplified trophic structure with low energy efficiency. The MG ecosystem was vulnerable to disruptions caused by all tested HNS, yet it revealed some long-term resilience. Understanding these impacts is vital for enhancing Spill Prevention, Control, and Countermeasure plans (SPCC) in remote marine areas and developing tools to assess stressors effects on these invaluable habitats.

Theta-tACS modulates cerebellar-related motor functions and cerebellar-cortical connectivity

OBJECTIVE

To evaluate the effects of cerebellar transcranial alternating current stimulation (tACS) delivered at cerebellar-resonant frequencies, i.e., theta (θ) and gamma (γ), on upper limb motor performance and cerebellum-primary motor cortex (M1) connectivity, as assessed by cerebellar-brain inhibition (CBI), in healthy subjects.

METHODS

Participants underwent cerebellar-tACS while performing three cerebellar-dependent motor tasks: (i) rhythmic finger-tapping, (ii) arm reaching-to-grasp ('grasping') and (iii) arm reaching-to-point ('pointing') an object. Also, we evaluated possible changes in CBI during cerebellar-tACS.

RESULTS

θ-tACS decreased movement regularity during the tapping task and increased the duration of the pointing task compared to sham- and γ-tACS. Additionally, θ-tACS increased the CBI effectiveness (greater inhibition). The effect of θ-tACS on movement rhythm correlated with CBI changes and less tapping regularity corresponded to greater CBI.

CONCLUSIONS

Cerebellar-tACS delivered at the θ frequency modulates cerebellar-related motor behavior and this effect is, at least in part, mediated by changes in the cerebellar inhibitory output onto M1. The effects of θ-tACS may be due to the modulation of cerebellar neurons that resonate to the θ rhythm.

SIGNIFICANCE

These findings contribute to a better understanding of the physiological mechanisms of motor control and provide new evidence on cerebellar non-invasive brain stimulation.

Interhemispheric imbalance and bradykinesia features in Parkinson's disease

In patients with Parkinson's disease, the connectivity between the two primary motor cortices may be altered. However, the correlation between asymmetries of abnormal interhemispheric connections and bradykinesia features has not been investigated. Furthermore, the potential effects of dopaminergic medications on this issue remain largely unclear. The aim of the present study is to investigate the interhemispheric connections in Parkinson's disease by transcranial magnetic stimulation and explore the potential relationship between interhemispheric inhibition and bradykinesia feature asymmetry in patients. Additionally, we examined the impact of dopaminergic therapy on neurophysiological and motor characteristics. Short- and long-latency interhemispheric inhibition was measured in 18 Parkinson's disease patients and 18 healthy controls, bilaterally. We also assessed the corticospinal and intracortical excitability of both primary motor cortices. We conducted an objective analysis of finger-tapping from both hands. Correlation analyses were performed to explore potential relationships among clinical, transcranial magnetic stimulation and kinematic data in patients. We found that short- and long-latency interhemispheric inhibition was reduced (less inhibition) from both hemispheres in patients than controls. Compared to controls, finger-tapping movements in patients were slower, more irregular, of smaller amplitudes and characterized by a progressive amplitude reduction during movement repetition (sequence effect). Among Parkinson's disease patients, the degree of short-latency interhemispheric inhibition imbalance towards the less affected primary motor cortex correlated with the global clinical motor scores, as well as with the sequence effect on the most affected hand. The greater the interhemispheric inhibition imbalance towards the less affected hemisphere (i.e. less inhibition from the less to the most affected primary motor cortex than that measured from the most to the less affected primary motor cortex), the more severe the bradykinesia in patients. In conclusion, the inhibitory connections between the two primary motor cortices in Parkinson's disease are reduced. The interhemispheric disinhibition of the primary motor cortex may have a role in the pathophysiology of specific bradykinesia features in patients, i.e. the sequence effect.

Deep brain stimulation of globus pallidus internus and subthalamic nucleus in Parkinson's disease: a multicenter, retrospective study of efficacy and safety

BACKGROUND

Deep brain stimulation (DBS) is an established therapeutic option in advanced Parkinson's disease (PD). Literature data and recent guidelines remain inconclusive about the best choice as a target between the subthalamic nucleus (STN) and the globus pallidus internus (GPi).

MATERIALS AND METHODS

We retrospectively reviewed the clinical efficacy outcomes of 48 DBS-implanted patients (33 STN-DBS and 15 GPi-DBS) at a short- (<1 year from the surgery) and long-term (2-5 years) follow-up. Also, clinical safety outcomes, including postoperative surgical complications and severe side effects, were collected.

RESULTS

We found no difference between STN-DBS and GPi-DBS in improving motor symptoms at short-term evaluation. However, STN-DBS achieved a more prominent reduction in oral therapy (L-DOPA equivalent daily dose, P = .02). By contrast, GPi-DBS was superior in ameliorating motor fluctuations and dyskinesia (MDS-UPDRS IV, P < .001) as well as motor experiences of daily living (MDS-UPDRS II, P = .03). The greater efficacy of GPi-DBS on motor fluctuations and experiences of daily living was also present at the long-term follow-up. We observed five serious adverse events, including two suicides, all among STN-DBS patients.

CONCLUSION

Both STN-DBS and GPi-DBS are effective in improving motor symptoms severity and complications, but GPi-DBS has a greater impact on motor fluctuations and motor experiences of daily living. These results suggest that the two targets should be considered equivalent in motor efficacy, with GPi-DBS as a valuable option in patients with prominent motor complications. The occurrence of suicides in STN-treated patients claims further attention in target selection.

Metastasis Models: Thermodynamics and Complexity

The thermodynamic formalism of nonequilibrium systems together with the theory of complex systems and systems biology offer an appropriate theoretical framework to explain the complexity observed at the macroscopic level in physiological phenomena. In turn, they allow the establishment of an appropriate conceptual and operational framework to address the study of phenomena such as the emergence and evolution of cancer.This chapter is organized as follows: In Subheading 1, an integrated vision of these disciplines is offered for the characterization of the emergence and evolution of cancer, seen as a nonlinear dynamic system, temporally and spatially self-organized out of thermodynamic equilibrium. The development of the various mathematical models and different techniques and approaches used in the characterization of cancer metastasis is presented in Subheading 2. Subheading 3 is devoted to the time course of cancer metastasis, with particular emphasis on the epithelial-mesenchymal transition (EMT henceforth) as well as chronotherapeutic treatments. In Subheading 4, models of the spatial evolution of cancer metastasis are presented. Finally, in Subheading 5, some conclusions and remarks are presented.

Facial emotion expressivity in patients with Parkinson's and Alzheimer's disease

Parkinson's disease (PD) and Alzheimer's disease (AD) are neurodegenerative disorders with some overlapping clinical features. Hypomimia (reduced facial expressivity) is a prominent sign of PD and it is also present in AD. However, no study has experimentally assessed hypomimia in AD and compared facial expressivity between PD and AD patients. We compared facial emotion expressivity in patients with PD, AD, and healthy controls (HCs). Twenty-four PD patients, 24 AD patients and 24 HCs were videotaped during neutral facial expressions and while posing six facial emotions (anger, surprise, disgust, fear, happiness, and sadness). Fifteen raters were asked to evaluate the videos using MDS-UPDRS-III (item 3.2) and to identify the corresponding emotion from a seven-forced-choice response format. We measured the percentage of accuracy, the reaction time (RT), and the confidence level (CL) in the perceived accuracy of the raters' responses. We found the highest MDS-UPDRS 3.2 scores in PD, and higher in AD than HCs. When evaluating the posed expression captures, raters identified a lower percentage of correct answers in the PD and AD groups than HCs. There was no difference in raters' response accuracy between the PD and AD. No difference was observed in RT and CL data between groups. Hypomimia in patients correlated positively with the global MDS-UPDRS-III and negatively with Mini Mental State Examination scores. PD and AD patients have a similar pattern of reduced facial emotion expressivity compared to controls. These findings hold potential pathophysiological and clinical implications.

Band-Specific Altered Cortical Connectivity in Early Parkinson's Disease and its Clinical Correlates

BACKGROUND

Functional connectivity (FC) has shown promising results in assessing the pathophysiology and identifying early biomarkers of neurodegenerative disorders, such as Parkinson's disease (PD).

OBJECTIVES

In this study, we aimed to assess possible resting-state FC abnormalities in early-stage PD patients using high-density electroencephalography (EEG) and to detect their clinical relationship with motor and non-motor PD symptoms.

METHODS

We enrolled 26 early-stage levodopa naïve PD patients and a group of 20 healthy controls (HC). Data were recorded with 64-channels EEG system and a source-reconstruction method was used to identify brain-region activity. FC was calculated using the weighted phase-lag index in θ, α, and β bands. Additionally, we quantified the unbalancing between β and lower frequencies through a novel index (β-functional ratio [FR]). Statistical analysis was conducted using a network-based statistical approach.

RESULTS

PD patients showed hypoconnected networks in θ and α band, involving prefrontal-limbic-temporal and frontoparietal areas, respectively, and a hyperconnected network in the β frequency band, involving sensorimotor-frontal areas. The θ FC network was negatively related to Non-Motor Symptoms Scale scores and α FC to the Movement Disorder Society-Sponsored Revision of the Unified Parkinson's Disease Rating Scale part III gait subscore, whereas β FC and β-FR network were positively linked to the bradykinesia subscore. Changes in θ FC and β-FR showed substantial reliability and high accuracy, precision, sensitivity, and specificity in discriminating PD and HC.

CONCLUSIONS

Frequency-specific FC changes in PD likely reflect the dysfunction of distinct cortical networks, which occur from the early stage of the disease. These abnormalities are involved in the pathophysiology of specific motor and non-motor PD symptoms, including gait, bradykinesia, mood, and cognition. © 2023 International Parkinson and Movement Disorder Society.

Current and novel infusion therapies for patients with Parkinson's disease

Advanced Parkinson's disease is characterized by periods of poor mobility, dyskinesia and progressive decline in functional independence of the affected person despite the manipulation of levodopa doses and the introduction of supplemental therapies such as catechol-O-methyl transferase inhibitors, monoamine oxidase-B inhibitors and dopamine agonists. The implementation of drug delivery systems allows to bypass problems related to irregular and often unpredictable intestinal absorption of oral levodopa, which significantly affects its bioavailability and contributes to the development and persistence of motor complications. Subcutaneous apomorphine and levodopa/carbidopa jejunal infusion systems have been available for many years and their efficacy is confirmed by randomized studies and long-term experience in many centers worldwide. Recently, a new formulation of levodopa/carbidopa infusion gel that includes the catechol-O-methyl transferase inhibitor Entacapone has been introduced to the market. The use of entacapone allows to reduce total daily dose of administered levodopa. Two different soluble formulations of levodopa/carbidopa (ND0612 and ABBV-951) have completed clinical development, and both can ensure subcutaneous delivery by a portable pump infusion system. ABBV-951 uses a foslevodopa/foscarbidopa formulation, both prodrugs to improve absorption and tolerability. Both systems provide effective improvement of motor complications and are likely to expand the therapeutic options in advanced patients. Future efforts should focus on the earlier detection of patients who are candidates for device-aided therapies, increasing appropriate referral and broadening the availability of these treatments globally.

Subtle changes in central dopaminergic tone underlie bradykinesia in essential tremor

INTRODUCTION

In this research, our primary objective was to explore the correlation between basal ganglia dopaminergic neurotransmission, assessed using 123I-FP-CIT (DAT-SPECT), and finger movements abnormalities in patients with essential tremor (ET) and Parkinson's disease (PD).

METHODS

We enrolled 16 patients with ET, 17 with PD, and 18 healthy controls (HC). Each participant underwent comprehensive clinical evaluations, kinematic assessments of finger tapping. ET and PD patients underwent DAT-SPECT imaging. The DAT-SPECT scans were subjected to both visual and semi-quantitative analysis using DaTQUANT®. We then investigated the correlations between the clinical, kinematic, and DAT-SPECT data, in patients.

RESULTS

Our findings confirm that individuals with ET exhibited slower finger tapping than HC. Visual evaluation of radiotracer uptake in both striata demonstrated normal levels within the ET patient cohort, while PD patients displayed reduced uptake. However, there was notable heterogeneity in the quantification of uptake within the striata among ET patients. Additionally, we found a correlation between the amount of radiotracer uptake in the striatum and movement velocity during finger tapping in patients. Specifically, lower radioligand uptake corresponded to decreased movement velocity (ET: coef. = 0.53, p-adj = 0.03; PD: coef. = 0.59, p-adj = 0.01).

CONCLUSION

The study's findings suggest a potential link between subtle changes in central dopaminergic tone and altered voluntary movement execution, in ET. These results provide further insights into the pathophysiology of ET. However, longitudinal studies are essential to determine whether the slight reduction in dopaminergic tone observed in ET patients represents a distinct subtype of the disease or could serve as a predictor for the clinical progression into PD.

The Effect of Ethanol Associated with Universal Adhesive on Resin Composite Adhesion to Different Dentin Depths: A Long-Term In Vitro Study

To evaluate the ethanol wet-bonding protocol with a universal adhesive in etch-andrinse and self-etch modes on microleakage and microtensile bond strength (μTBS) of resin composite to different dentin depth. Molars were distributed into groups according to protocol and dentin depth: universal adhesive (C - control), ethanol + universal adhesive (E), and phosphoric acid etch + ethanol + universal adhesive (PA+E). All protocols were applied to dentin at superficial, middle and deep depths. The specimens (n = 10) were submitted to microleakage and μTBS tests. Half of specimens were submitted to thermocycling (10,000 cycles; 5∘C/55∘C). Data were submitted to Spearman correlation (μTBS x microleakage) and three-way ANOVA (protocol, aging and depth), followed by Bonferroni post hoc test (α=0.05). PA+E group showed highest μTBS and lowest microleakage mean values in 24h. All groups presented similar μTBS mean values after thermocycling. The deep dentin showed less stable μTBS results. PA+E group presented highest microleakage mean values after thermocycling. Spearman's correlation showed a strong correlation between microleakage and μTBS. The PA+E group improved immediate adhesion and E group promoted a more stable μTBS in the long-term adhesion of universal adhesive. The aging for all protocols jeopardized the stability of the hybrid layer. The ethanol wet bonding technique associated with universal adhesive has enhanced the immediate result of the resin composite adhesion.

Objective measurement versus clinician-based assessment for Parkinson's disease

INTRODUCTION

Although clinician-based assessment through standardized clinical rating scales is currently the gold standard for quantifying motor impairment in Parkinson's disease (PD), it is not without limitations, including intra- and inter-rater variability and a degree of approximation. There is increasing evidence supporting the use of objective motion analyses to complement clinician-based assessment. Objective measurement tools hold significant potential for improving the accuracy of clinical and research-based evaluations of patients.

AREAS COVERED

The authors provide several examples from the literature demonstrating how different motion measurement tools, including optoelectronics, contactless and wearable systems allow for both the objective quantification and monitoring of key motor symptoms (such as bradykinesia, rigidity, tremor, and gait disturbances), and the identification of motor fluctuations in PD patients. Furthermore, they discuss how, from a clinician's perspective, objective measurements can help in various stages of PD management.

EXPERT OPINION

In our opinion, sufficient evidence supports the assertion that objective monitoring systems enable accurate evaluation of motor symptoms and complications in PD. A range of devices can be utilized not only to support diagnosis but also to monitor motor symptom during the disease progression and can become relevant in the therapeutic decision-making process.

Short-term plasticity of the motor cortex compensates for bradykinesia in Parkinson's disease

Patients with Parkinson's disease (PD) show impaired short-term potentiation (STP) mechanisms in the primary motor cortex (M1). However, the role played by this neurophysiological abnormality in bradykinesia pathophysiology is unknown. In this study, we used a multimodal neuromodulation approach to test whether defective STP contributes to bradykinesia. We evaluated STP by measuring motor-evoked potential facilitation during 5 Hz-repetitive transcranial magnetic stimulation (rTMS) and assessed repetitive finger tapping movements through kinematic techniques. Also, we used transcranial alternating current stimulation (tACS) to drive M1 oscillations and experimentally modulate bradykinesia. STP was assessed during tACS delivered at beta (β) and gamma (γ) frequency, and during sham-tACS. Data were compared to those recorded in a group of healthy subjects. In PD, we found that STP was impaired during sham- and γ-tACS, while it was restored during β-tACS. Importantly, the degree of STP impairment was associated with the severity of movement slowness and amplitude reduction. Moreover, β-tACS-related improvements in STP were linked to changes in movement slowness and intracortical GABA-A-ergic inhibition during stimulation, as assessed by short-interval intracortical inhibition (SICI). Patients with prominent STP amelioration had greater SICI reduction (cortical disinhibition) and less slowness worsening during β-tACS. Dopaminergic medications did not modify β-tACS effects. These data demonstrate that abnormal STP processes are involved in bradykinesia pathophysiology and return to normal levels when β oscillations increase. STP changes are likely mediated by modifications in GABA-A-ergic intracortical circuits and may represent a compensatory mechanism against β-induced bradykinesia in PD.

Relationship between the interlimb transfer of a visuomotor learning task and interhemispheric inhibition in healthy humans

The "interlimb transfer" phenomenon consists of improved performance of the trained and untrained contralateral limbs after unilateral motor practice. We here assessed whether a visuomotor learning task can be transferred from one hemisphere to the other, whether this occurs symmetrically, and the cortical neurophysiological correlates of this phenomenon, focusing on interhemispheric connectivity measures. We enrolled 33 healthy subjects (age range: 24-73 years). Participants underwent two randomized sessions, which investigated the transfer from the dominant to the nondominant hand and vice versa. Measures of cortical and intracortical excitability and interhemispheric inhibition were assessed through transcranial magnetic stimulation before and after a visuomotor task. The execution of the visuomotor task led to an improvement in motor performance with the dominant and nondominant hands and induced a decrease in intracortical inhibition in the trained hemisphere. Participants were also able to transfer the visuomotor learned skill. The interlimb transfer, however, only occurred from the dominant to the nondominant hand and positively correlated with individual learning-related changes in interhemispheric inhibition. We here demonstrated that the "interlimb transfer" of a visuomotor task occurs asymmetrically and relates to the modulation of specific inhibitory interhemispheric connections. The study results have pathophysiological, clinical, and neuro-rehabilitative implications.

Combining Transcranial Magnetic Stimulation and Deep Brain Stimulation: Current Knowledge, Relevance and Future Perspectives

Deep brain stimulation (DBS) has emerged as an invasive neuromodulation technique for the treatment of several neurological disorders, but the mechanisms underlying its effects remain partially elusive. In this context, the application of Transcranial Magnetic Stimulation (TMS) in patients treated with DBS represents an intriguing approach to investigate the neurophysiology of cortico-basal networks. Experimental studies combining TMS and DBS that have been performed so far have mainly aimed to evaluate the effects of DBS on the cerebral cortex and thus to provide insights into DBS's mechanisms of action. The modulation of cortical excitability and plasticity by DBS is emerging as a potential contributor to its therapeutic effects. Moreover, pairing DBS and TMS stimuli could represent a method to induce cortical synaptic plasticity, the therapeutic potential of which is still unexplored. Furthermore, the advent of new DBS technologies and novel treatment targets will present new research opportunities and prospects to investigate brain networks. However, the application of the combined TMS-DBS approach is currently limited by safety concerns. In this review, we sought to present an overview of studies performed by combining TMS and DBS in neurological disorders, as well as available evidence and recommendations on the safety of their combination. Additionally, we outline perspectives for future research by highlighting knowledge gaps and possible novel applications of this approach.

Real-Time Monitoring of Infectious Disease Outbreaks with a Combination of Google Trends Search Results and the Moving Epidemic Method: A Respiratory Syncytial Virus Case Study

The COVID-19 pandemic has disrupted the seasonal patterns of several infectious diseases. Understanding when and where an outbreak may occur is vital for public health planning and response. We usually rely on well-functioning surveillance systems to monitor epidemic outbreaks. However, not all countries have a well-functioning surveillance system in place, or at least not for the pathogen in question. We utilized Google Trends search results for RSV-related keywords to identify outbreaks. We evaluated the strength of the Pearson correlation coefficient between clinical surveillance data and online search data and applied the Moving Epidemic Method (MEM) to identify country-specific epidemic thresholds. Additionally, we established pseudo-RSV surveillance systems, enabling internal stakeholders to obtain insights on the speed and risk of any emerging RSV outbreaks in countries with imprecise disease surveillance systems but with Google Trends data. Strong correlations between RSV clinical surveillance data and Google Trends search results from several countries were observed. In monitoring an upcoming RSV outbreak with MEM, data collected from both systems yielded similar estimates of country-specific epidemic thresholds, starting time, and duration. We demonstrate in this study the potential of monitoring disease outbreaks in real time and complement classical disease surveillance systems by leveraging online search data.

Assessing the interaction between L-dopa and γ-transcranial alternating current stimulation effects on primary motor cortex plasticity in Parkinson's disease

L-dopa variably influences transcranial magnetic stimulation (TMS) parameters of motor cortex (M1) excitability and plasticity in Parkinson's disease (PD). In patients OFF dopaminergic medication, impaired M1 plasticity and defective GABA-A-ergic inhibition can be restored by boosting gamma (γ) oscillations via transcranial alternating current stimulation (tACS) during intermittent theta-burst stimulation (iTBS). However, it is unknown whether L-dopa modifies the beneficial effects of iTBS-γ-tACS on M1 in PD. In this study, a PD patients group underwent combined iTBS-γ-tACS and iTBS-sham-tACS, each performed both OFF and ON dopaminergic therapy (four sessions in total). Motor evoked potentials (MEPs) elicited by single TMS pulses and short-interval intracortical inhibition (SICI) were assessed before and after iTBS-tACS. We also evaluated possible SICI changes during γ-tACS delivered alone in OFF and ON conditions. The amplitude of MEP elicited by single TMS pulses and the degree of SICI inhibition significantly increased after iTBS-γ-tACS. The amount of change produced by iTBS-γ-tACS was similar in patients OFF and ON therapy. Finally, γ-tACS (delivered alone) modulated SICI during stimulation and this effect did not depend on the dopaminergic condition of patients. In conclusion, boosting cortical γ oscillatory activity via tACS during iTBS improved M1 plasticity and enhanced GABA-A-ergic transmission in PD patients to the same extent regardless of dopaminergic state. These results suggest a lack of interaction between L-dopa and γ-tACS effects at the M1 level. The possible neural substrate underlying iTBS-γ tACS effects, that is, γ-resonant GABA-A-ergic interneurons activity, may explain our findings.

May Bradykinesia Features Aid in Distinguishing Parkinson's Disease, Essential Tremor, And Healthy Elderly Individuals?

BACKGROUND

Bradykinesia is the hallmark feature of Parkinson's disease (PD); however, it can manifest in other conditions, including essential tremor (ET), and in healthy elderly individuals.

OBJECTIVE

Here we assessed whether bradykinesia features aid in distinguishing PD, ET, and healthy elderly individuals.

METHODS

We conducted simultaneous video and kinematic recordings of finger tapping in 44 PD patients, 69 ET patients, and 77 healthy elderly individuals. Videos were evaluated blindly by expert neurologists. Kinematic recordings were blindly analyzed. We calculated the inter-raters agreement and compared data among groups. Density plots assessed the overlapping in the distribution of kinematic data. Regression analyses and receiver operating characteristic curves determined how the kinematics influenced the likelihood of belonging to a clinical score category and diagnostic group.

RESULTS

The inter-rater agreement was fair (Fleiss K = 0.32). Rater found the highest clinical scores in PD, and higher scores in ET than healthy elderly individuals (p < 0.001). In regard to kinematic analysis, the groups showed variations in movement velocity, with PD presenting the slowest values and ET displaying less velocity than healthy elderly individuals (all ps < 0.001). Additionally, PD patients showed irregular rhythm and sequence effect. However, kinematic data significantly overlapped. Regression analyses showed that kinematic analysis had high specificity in differentiating between PD and healthy elderly individuals. Nonetheless, accuracy decreased when evaluating subjects with intermediate kinematic values, i.e., ET patients.

CONCLUSION

Despite a considerable degree of overlap, bradykinesia features vary to some extent in PD, ET, and healthy elderly individuals. Our findings have implications for defining bradykinesia and categorizing patients.

Priority setting for restoration in surrounding savannic areas of the Brazilian Pantanal based on soil loss risk and agrarian structure

Soil health is at the core of the sustainability agenda. As in many agroecosystems in the tropics, soil erosion is a major issue in poorly managed pasturelands. A noteworthy case is located in the Upper Taquari River Basin (UTRB), as part of the Upper Paraguay Basin on the plateau with drainage waters for the Taquari megafan in the Brazilian Pantanal. Here we combine slope (S-factor), erodibility (E-factor), rainfall-rainy day ratio (R-factor), and vegetation and soil indices (C-factor) to locate erosion risk and prioritize eco-engineering interventions via palisades and small dams in UTRB. The method consisted of assessing distinct weights between Universal Soil Loss Equation (USLE) factors in a GIS platform, providing 35 combinations of classes as low, moderate, high, and very high erosive risk. The validation of the method was based on the ravine and plain ground truths obtained from high-resolution raster data. The best weight of USLE factors aids to locate critical erosive sites and vegetation patterns. Then, erosion risk and interventions were analyzed according to land use and rural property sizes in the government's Rural Environmental Registry (CAR) database. Overall, the natural factors of slope and erodibility in a proportion of 25% and 75% in GIS algebra provided the best mapping accuracy result. About 65% of the UTRB has high or very high erosion risks, and 70% of the available area can be acknowledged as degraded pasturelands. A total of 4744 erosion interventions were recorded, with an accuracy of 65.28% and 61.15% for check dams and palisades interventions, respectively. The number of necessary interventions in areas of native vegetation was almost 50% higher than in pasturelands. Even though micro landowners occupy most of the watershed, large properties have about ten times as many areas at high risk of erosion. The mutual cooperation between properties, independently of size, is supported by governmental public policies like incentives for ecosystem services restoration of critical gullies, with CAR compliance and fiscalization.

Dystonia, chorea, hemiballismus and other dyskinesias

Hyperkinesias are heterogeneous involuntary movements that significantly differ in terms of clinical and semeiological manifestations, including rhythm, regularity, speed, duration, and other factors that determine their appearance or suppression. Hyperkinesias are due to complex, variable, and largely undefined pathophysiological mechanisms that may involve different brain areas. In this chapter, we specifically focus on dystonia, chorea and hemiballismus, and other dyskinesias, specifically, levodopa-induced, tardive, and cranial dyskinesia. We address the role of neurophysiological studies aimed at explaining the pathophysiology of these conditions. We mainly refer to human studies using surface and invasive in-depth recordings, as well as spinal, brainstem, and transcortical reflexology and non-invasive brain stimulation techniques. We discuss the extent to which the neurophysiological abnormalities observed in hyperkinesias may be explained by pathophysiological models. We highlight the most relevant issues that deserve future research efforts. The potential role of neurophysiological assessment in the clinical context of hyperkinesia is also discussed.

P396 OUR CERTIFIED SYNCOPE UNIT EXPERIENCE; FROM DIAGNOSTIC APPROPRIATENESS TO DEVICE IMPLANTS, FROM PATIENT EDUCATION TO THE IMPACT OF THE COVID–19 PANDEMIC. REPORT ON TWO “DIFFICULT” YEARS

Syncope is a frequent medical problem with an incidence of about 6.2/1000 people/year, with important impact on the patients quality of life and often difficult to diagnose and manage; in this regard, the Syncope Units certified by the Italian Group for the study of syncope were created. The following describes our experience over the last 30 months characterized by significant difficulties due to the COVID–19 pandemic. Our Syncope Unit, included in the OU of Cardiology, includes 3 doctors, 3 cardiology technicians, 2 nurses; the activity is three times a week in terms of clinic and HUTT (Head up tilt test). In 2019, 54 HUTTs were performed on patients with an average age of 67 years 50% male, with indication of vasovagal syncope (VVS) for 78% of cases, presyncope and other indications for the remaining 21%, requested by other services. The HUTT was positive for cardioinhibitory and sinus–carotid syncope with indication for Pacemaker implantation (with closed loop stimulation algorithm – CLS) for 22% of cases. In 12% of patients, an ECG–Loop recorder (ILR) was indicated, but 42% of these refused this procedure. In 2020, 32 HUTTs were performed, the same average age, with 86% indication of VVS syncope. The indication for a pacemaker implant was 15% as well as for an ILR implant. 33 to 38% of patients were educated, providing dedicated material, on the prevention of syncope. About 4% of patients refused to undergo the HUTT after the explanation of its performing modalities. The first 6 months of 2021 showed a similar trend to that of 2019. The data show a good appropriateness of the indications to the HUTT and a subsequent PM implantation rate similar to the data available in the literature. The device with CLS has shown benefits in reducing syncopal recurrences at 6 months by over 25%; only 3% of the ILRs were followed by PM implantation. The HUTT, despite of low sensitivity and specificity, is confirmed as a valid VVS characterization tool but sometimes the patient frightened by its performing methods. The COVID–19 pandemic significantly impacted our activity, related to the outpatient in office activities stop and to the shift of operators in COVID areas. We had a 40% reduction in visits and HUTTs performed with consequent missed and/or delayed diagnoses.

Action Selection and Motor Decision Making: Insights from Transcranial Magnetic Stimulation

In everyday life, goal-oriented motor behaviour relies on the estimation of the rewards/costs associated with alternative actions and on the appropriate selection of movements. Motor decision making is defined as the process by which a motor plan is chosen among a set of competing actions based on the expected value. In the present literature review we discuss evidence from transcranial magnetic stimulation (TMS) studies of motor control. We focus primarily on studies of action selection for instructed movements and motor decision making. In the first section, we delve into the usefulness of various TMS paradigms to characterise the contribution of motor areas and distributed brain networks to cued action selection. Then, we address the influence of motivational information (e.g., reward and biomechanical cost) in guiding action choices based on TMS findings. Finally, we conclude that TMS represents a powerful tool for elucidating the neurophysiological mechanisms underlying action choices in humans.

Low-Intensity Transcranial Ultrasound Stimulation: Mechanisms of Action and Rationale for Future Applications in Movement Disorders

Low-intensity transcranial ultrasound stimulation (TUS) is a novel non-invasive brain stimulation technique that uses acoustic energy to induce changes in neuronal activity. However, although low-intensity TUS is a promising neuromodulation tool, it has been poorly studied as compared to other methods, i.e., transcranial magnetic and electrical stimulation. In this article, we first focus on experimental studies in animals and humans aimed at explaining its mechanisms of action. We then highlight possible applications of TUS in movement disorders, particularly in patients with parkinsonism, dystonia, and tremor. Finally, we highlight the knowledge gaps and possible limitations that currently limit potential TUS applications in movement disorders. Clarifying the potential role of TUS in movement disorders may further promote studies with therapeutic perspectives in this field.

Transcranial alternating current stimulation modulates cortical processing of somatosensory information in a frequency- and time-specific manner

Neural oscillations can be modulated by non-invasive brain stimulation techniques, including transcranial alternating current stimulation (tACS). However, direct evidence of tACS effects at the cortical level in humans is still limited. In a tACS-electroencephalography co-registration setup, we investigated the ability of tACS to modulate cortical somatosensory information processing as assessed by somatosensory-evoked potentials (SEPs). To better elucidate the neural substrates of possible tACS effects we also recorded peripheral and spinal SEPs components, high-frequency oscillations (HFOs), and long-latency reflexes (LLRs). Finally, we studied whether changes were limited to the stimulation period or persisted thereafter. SEPs, HFOs, and LLRs were recorded during tACS applied at individual mu and beta frequencies and at the theta frequency over the primary somatosensory cortex (S1). Sham-tACS was used as a control condition. In a separate experiment, we assessed the time course of mu-tACS effects by recording SEPs before (T0), during (T1), and 1 min (T2) and 10 min (T3) after stimulation. Mu-tACS increased the amplitude of the N20 component of SEPs compared to both sham and theta-tACS. No differences were found between sham, beta-, and theta-tACS conditions. Also, peripheral and spinal SEPs, P25, HFOs, and LLRs did not change during tACS. Finally, mu-tACS-induced modulation of N20 amplitude specifically occurred during stimulation (T1) and vanished afterwards (i.e., at T2 and T3). Our findings suggest that TACS applied at the individual mu frequency is able to modulate early somatosensory information processing at the S1 level and the effect is limited to the stimulation period.

Life-history data of a key amphipod species from three NE Atlantic estuaries under different levels of anthropogenic pressure

Knowledge on population dynamics of ecosystem's key-species is invaluable to understand how populations will respond to natural and human-induced perturbations. The amphipod Echinogammarus marinus is a key-species from European estuarine habitats with a distribution ranging from Norway to Portugal [1]. The present article contains supportive data related to a research article entitled ‘Comparing production and life-history traits of a key amphipod species within and between estuaries under different levels of anthropogenic pressure’ [2]. The present dataset presents the density, biomass, fecundity, and production of E. marinus in three estuaries under different anthropogenic pressure and, within each estuary, at three sampling sites, which differed in terms of the distance to the estuary mouth, vegetation cover, and organic matter content. Monthly environmental abiotic data and seasonal concentration of PAH and other contaminants are also provided. Sampling took place monthly for 13 months at low tide on intertidal mudflats. At each site, Fucus fronds containing E. marinus individuals were randomly collected. All E. marinus individuals were counted, sexed, and measured under a binocular stereo microscope to estimate the density and the biomass of E. marinus in Fucus fronds. Finally, the annual production of E. marinus at each sampling site was estimated through the size-frequency method. This dataset may be used to compare population traits of E. marinus populations across different estuaries and it may overall assist designing studies regarding population dynamics and designing management strategies in coastal systems, namely targeting at habitat conservation and restoration.

Transcranial magnetic stimulation as a tool to induce and explore plasticity in humans

Activity-dependent synaptic plasticity is the main theoretical framework to explain mechanisms of learning and memory. Synaptic plasticity can be explored experimentally in animals through various standardized protocols for eliciting long-term potentiation and long-term depression in hippocampal and cortical slices. In humans, several non-invasive protocols of repetitive transcranial magnetic stimulation and transcranial direct current stimulation have been designed and applied to probe synaptic plasticity in the primary motor cortex, as reflected by long-term changes in motor evoked potential amplitudes. These protocols mimic those normally used in animal studies for assessing long-term potentiation and long-term depression. In this chapter, we first discuss the physiologic basis of theta-burst stimulation, paired associative stimulation, and transcranial direct current stimulation. We describe the current biophysical and theoretical models underlying the molecular mechanisms of synaptic plasticity and metaplasticity, defined as activity-dependent changes in neural functions that modulate subsequent synaptic plasticity such as long-term potentiation (LTP) and long-term depression (LTD), in the human motor cortex including calcium-dependent plasticity, spike-timing-dependent plasticity, the role of N-methyl-d-aspartate-related transmission and gamma-aminobutyric-acid interneuronal activity. We also review the putative microcircuits responsible for synaptic plasticity in the human motor cortex. We critically readdress the issue of variability in studies investigating synaptic plasticity and propose available solutions. Finally, we speculate about the utility of future studies with more advanced experimental approaches.

Motor Cortical Network Excitability in Parkinson's Disease

BACKGROUND

Motor impairment in Parkinson's disease (PD) reflects changes in the basal ganglia-thalamocortical circuit converging on the primary motor cortex (M1) and supplementary motor area (SMA). Previous studies assessed M1 excitability in PD using transcranial magnetic stimulation (TMS)-evoked electromyographic activity. TMS-evoked electroencephalographic activity may unveil broader motor cortical network changes in PD.

OBJECTIVE

The aim was to assess motor cortical network excitability in PD.

METHODS

We compared TMS-evoked cortical potentials (TEPs) from M1 and the pre-SMA between 20 PD patients tested off and on medication and 19 healthy controls (HCs) and investigated possible correlations with bradykinesia.

RESULTS

Off PD patients compared to HCs had smaller P30 responses from the M1s contralateral (M1+) and ipsilateral (M1-) to the most bradykinetic side and increased pre-SMA N40. Dopaminergic therapy normalized the amplitude of M1+ and M1- P30 as well as pre-SMA N40. We found a positive correlation between M1+ P30 amplitude and bradykinesia in off PD patients.

CONCLUSIONS

Changes in M1 P30 and pre-SMA N40 in PD suggest that M1 excitability is reduced on both sides, whereas pre-SMA excitability is increased. The effect of dopaminergic therapy and the clinical correlation suggest that these cortical changes may reflect abnormal basal ganglia-thalamocortical activity. TMS electroencephalography provides novel insight into motor cortical network changes related to the pathophysiology of PD. © 2022 International Parkinson and Movement Disorder Society.

Comparing production and life-history traits of a key amphipod species within and between estuaries under different levels of anthropogenic pressure

Inter-population variability may arise as a response to adverse natural and anthropogenic stressors. The dynamics of a key amphipod species (Echinogammarus marinus) was followed during ≈ 1-year at its southerly range (NW Portugal), in three estuaries with different levels of anthropogenic pressure (High - Ave estuary; Moderate - Mondego estuary; Low - Minho estuary). We hypothesised that E. marinus populations would present lower production and fitness, and higher intersexuality incidence with increasing anthropogenic pressure. According to a GAM model explaining ≈70% of the observed variability, E. marinus biomass depends on temperature, organic matter, Fucus area and time of the year. Significant differences were found between the gammarid biomass in Minho and Mondego estuaries and within sites from the same estuary. As expected, Ave estuary exhibited the lowest average annual production, abundance and fecundity rates. However, the highest average production was found in Mondego and not in Minho estuary, although the turnover ratio (P/B) of both estuaries was very similar. Besides the system's global ecological status, E. marinus also seems to respond to microhabitat conditions, which may explain the spatial heterogeneity observed in the amphipod production within the same estuary. Intersexuality prevalence was negligible in the three populations, which does not support the idea of a link between anthropogenic pressure and intersexuality in E. marinus. We argue that the dependence of E. marinus on Fucus sp. should be further investigated to fully understand the role of both fucoids and the gammarid in coastal foodwebs.

TMS-EEG Biomarkers of Amnestic Mild Cognitive Impairment Due to Alzheimer's Disease: A Proof-of-Concept Six Years Prospective Study

Background: Early and affordable identification of subjects with amnestic mild cognitive impairment (aMCI) who will convert to Alzheimer's disease (AD) is a major scientific challenge. Objective: To investigate the neurophysiological hallmarks of sensorimotor cortex function in aMCI under the hypothesis that some may represent the plastic rearrangements induced by neurodegeneration, hence predictors of future conversion to AD. We sought to determine (1) whether the sensorimotor network shows peculiar alterations in patients with aMCI and (2) if sensorimotor network alterations predict long-term disease progression at the individual level. Methods: We studied several transcranial magnetic stimulation (TMS)-electroencephalogram (EEG) parameters of the sensorimotor cortex in a group of patients with aMCI and followed them for 6 years. We then identified aMCI who clinically converted to AD [prodromal to AD-MCI (pAD-MCI)] and those who remained cognitively stable [non-prodromal to AD-MCI (npAD-MCI)]. Results: Patients with aMCI showed reduced motor cortex (M1) excitability and disrupted EEG synchronization [decreased intertrial coherence (ITC)] in alpha, beta and gamma frequency bands compared to the control subjects. The degree of alteration in M1 excitability and alpha ITC was comparable between pAD-MCI and npAD-MCI. Importantly, beta and gamma ITC impairment in the stimulated M1 was greater in pAD-MCI than npAD-MCI. Furthermore, an additional parameter related to the waveform shape of scalp signals, reflecting time-specific alterations in global TMS-induced activity [stability of the dipolar activity (sDA)], discriminated npAD-MCI from MCI who will convert to AD. Discussion: The above mentioned specific cortical changes, reflecting deficit of synchronization within the cortico-basal ganglia-thalamo-cortical loop in aMCI, may reflect the pathological processes underlying AD. These changes could be tested in larger cohorts as neurophysiological biomarkers of AD.

Long-term changes in short-interval intracortical facilitation modulate motor cortex plasticity and L-dopa-induced dyskinesia in Parkinson's disease

BACKGROUND

Abnormal glutamatergic neurotransmission in the primary motor cortex (M1) contributes to Parkinson's disease (PD) pathophysiology and is related to l-dopa-induced dyskinesia (LID). We previously showed that short-term treatment with safinamide, a monoamine oxidase type-B inhibitor with anti-glutamatergic properties, improves abnormally enhanced short-interval intracortical facilitation (SICF) in PD patients.

OBJECTIVE

To examine whether a long-term SICF modulation has beneficial effects on clinical measures, including LID severity, and whether these changes parallel improvement in cortical plasticity mechanisms in PD.

METHODS

We tested SICF in patients with and without LID before (S0) and after short- (14 days - S1) and long-term (12 months - S2) treatment with safinamide 100 mg/day. Possible changes in M1 plasticity were assessed using intermittent theta-burst stimulation (iTBS). Finally, we correlated safinamide-related neurophysiological changes with modifications in clinical scores.

RESULTS

SICF was enhanced at S0, and prominently in patients with LID. Safinamide normalized SICF at S1, and this effect persisted at S2. Impaired iTBS-induced plasticity was present at S0 and safinamide restored this alteration at S2. There was a significant correlation between the degree of SICF and the amount of iTBS-induced plasticity at S0 and S2. In patients with LID, the degree of SICF at S0 and S2 correlated with long-term changes in LID severity.

CONCLUSIONS

Altered SICF contributes to M1 plasticity impairment in PD. Both SICF and M1 plasticity improve after long-term treatment with safinamide. The abnormality in SICF-related glutamatergic circuits plays a role in LID pathophysiology, and its long-term modulation may prevent LID worsening over time.

Practical application of synthetic head models in real ballistic cases

In shooting crimes, ballistics tests are often recommended in order to reproduce the wound characteristics of the involved persons. For this purpose, several "simulants" can be used. However, despite the efforts in the research of "surrogates" in the field of forensic ballistic, the development of synthetic models needs still to be improved through a validation process based on specific real caseworks. This study has been triggered by the findings observed during the autopsy performed on two victims killed in the same shooting incident, with similar wounding characteristics; namely two retained head shots with ricochet against the interior wall of the skull; both projectiles have been recovered during the autopsies after migration in the brain parenchyma. The thickness of the different tissues and structures along the bullets trajectories as well as the incident angles between the bullets paths and the skull walls have been measured and reproduced during the assemblage of the synthetic head models. Two different types of models ("open shape" and "spherical") have been assembled using leather, polyurethane and gelatine to simulate respectively skin, bone and soft tissues. Six shots have been performed in total. The results of the models have been compared to the findings of post-mortem computed tomography (PMCT) and the autopsy findings.Out of the six shots, two perforated the models and four were retained. When the projectile was retained, the use of both models allowed reproducing the wounds characteristics observed on both victims in terms of penetration and ricochet behaviour. However, the projectiles recovered from the models showed less deformation than the bullets collected during the autopsies. The "open shape" model allowed a better controlling on the shooting parameters than the "spherical" model. Finally, the difference in bullet deformation could be caused by the choice of the bone simulant, which might under-represent either the strength or the density of the human bone. In our opinion, it would be worth to develop a new, more representative material for ballistic which simulates the human bone.

Bradykinesia in motoneuron diseases

OBJECTIVE

Only few studies investigated voluntary movement abnormalities in patients with motoneuron diseases (MNDs) or their neurophysiological correlates. We aimed to kinematically assess finger tapping abnormalities in patients with amyotrophic lateral sclerosis (ALS) and primary lateral sclerosis (PLS), as compared to healthy controls (HCs), and their relationship with motoneuron involvement.

METHODS

Fourteen ALS and 5 PLS patients were enrolled. Finger tapping was assessed by a motion analysis system. Patients underwent a central motor conduction time assessment, a motor nerve conduction study, and needle electromyography. Data were compared to those of 79 HCs using non-parametric tests. Possible relationships between clinical, kinematic, and neurophysiological data were assessed in patients.

RESULTS

As a major finding, ALS and PLS patients performed finger tapping slower than HCs. In both conditions, movement slowness correlated with muscle strength. In ALS, movement slowness also correlated with the amplitude of the compound muscle action potential recorded from the muscles involved in the task and with denervation activity. No correlations were found between slowness, measures of upper motoneuron involvement, and other clinical and neurophysiological data.

CONCLUSIONS

This study provides novel information on voluntary movement abnormalities in MNDs.

SIGNIFICANCE

The results highlight the pathophysiological role of motoneurons in generating movement slowness.

Driving motor cortex oscillations modulates bradykinesia in Parkinson's disease

In Parkinson's disease (PD) patients, beta (β) and gamma (γ) oscillations are altered in the basal ganglia, and this abnormality contributes to the pathophysiology of bradykinesia. However, it is unclear whether β and γ rhythms at the primary motor cortex (M1) level influence bradykinesia. Transcranial alternating current stimulation (tACS) can modulate cortical rhythms by entraining endogenous oscillations. We tested whether β- and γ-tACS on M1 modulate bradykinesia in PD patients by analyzing the kinematic features of repetitive finger tapping, including movement amplitude, velocity, and sequence effect, recorded during β-, γ-, and sham tACS. We also verified whether possible tACS-induced bradykinesia changes depended on modifications in specific M1 circuits, as assessed by short-interval intracortical inhibition (SICI) and short-latency afferent inhibition (SAI). Patients were studied OFF and ON dopaminergic therapy. Results were compared to those obtained in a group of healthy subjects (HS). In patients, movement velocity significantly worsened during β-tACS and movement amplitude improved during γ-tACS, while the sequence effect did not change. In addition, SAI decreased (reduced inhibition) during β-tACS and SICI decreased during both γ- and β-tACS in PD. The effects of tACS were comparable between OFF and ON sessions. In patients OFF therapy, the degree of SICI modulation during β- and γ-tACS correlated with movement velocity and amplitude changes. Moreover, there was a positive correlation between the effect of γ-tACS on movement amplitude and motor symptoms severity. Our results show that cortical β and γ oscillations are relevant in the pathophysiology of bradykinesia in PD and that changes in inhibitory GABA-A-ergic interneuronal activity may reflect compensatory M1 mechanisms to counteract bradykinesia. In conclusion, abnormal oscillations at the M1 level of the basal ganglia-thalamo-cortical network play a relevant role in the pathophysiology of bradykinesia in PD.

Pathophysiological Mechanisms and Experimental Pharmacotherapy for L-Dopa-Induced Dyskinesia

L-dopa-induced dyskinesia (LID) is the most frequent motor complication associated with chronic L-dopa treatment in Parkinson’s disease (PD). Recent advances in the understanding of the pathophysiological mechanisms underlying LID suggest that abnormalities in multiple neurotransmitter systems, in addition to dopaminergic nigrostriatal denervation and altered dopamine release and reuptake dynamics at the synaptic level, are involved in LID development. Increased knowledge of neurobiological LID substrates has led to the development of several drug candidates to alleviate this motor complication. However, with the exception of amantadine, none of the pharmacological therapies tested in humans have demonstrated clinically relevant beneficial effects. Therefore, LID management is still one of the most challenging problems in the treatment of PD patients. In this review, we first describe the known pathophysiological mechanisms of LID. We then provide an updated report of experimental pharmacotherapies tested in clinical trials of PD patients and drugs currently under study to alleviate LID. Finally, we discuss available pharmacological LID treatment approaches and offer our opinion of possible issues to be clarified and future therapeutic strategies.

Contribution of TMS and TMS-EEG to the Understanding of Mechanisms Underlying Physiological Brain Aging

In the human brain, aging is characterized by progressive neuronal loss, leading to disruption of synapses and to a degree of failure in neurotransmission. However, there is increasing evidence to support the notion that the aged brain has a remarkable ability to reorganize itself, with the aim of preserving its physiological activity. It is important to develop objective markers able to characterize the biological processes underlying brain aging in the intact human, and to distinguish them from brain degeneration associated with many neurological diseases. Transcranial magnetic stimulation (TMS), coupled with electromyography or electroencephalography (EEG), is particularly suited to this aim, due to the functional nature of the information provided, and thanks to the ease with which it can be integrated with behavioral manipulation. In this review, we aimed to provide up to date information about the role of TMS and TMS-EEG in the investigation of brain aging. In particular, we focused on data about cortical excitability, connectivity and plasticity, obtained by using readouts such as motor evoked potentials and transcranial evoked potentials. Overall, findings in the literature support an important potential contribution of TMS to the understanding of the mechanisms underlying normal brain aging. Further studies are needed to expand the current body of information and to assess the applicability of TMS findings in the clinical setting.