Preventive exercise and physical rehabilitation promote long-term potentiation-like plasticity expression in patients with multiple sclerosis

BACKGROUND AND PURPOSE

Loss of long-term potentiation (LTP) expression has been associated with a worse disease course in relapsing-remitting multiple sclerosis (RR-MS) and represents a pathophysiological hallmark of progressive multiple sclerosis (PMS). Exercise and physical rehabilitation are the most prominent therapeutic approaches to promote synaptic plasticity. We aimed to explore whether physical exercise is able to improve the expression of LTP-like plasticity in patients with multiple sclerosis (MS).

METHODS

In 46 newly diagnosed RR-MS patients, we explored the impact of preventive exercise on LTP-like plasticity as assessed by intermittent theta-burst stimulation. Patients were divided into sedentary or active, based on physical activity performed during the 6 months prior to diagnosis. Furthermore, in 18 patients with PMS, we evaluated the impact of an 8-week inpatient neurorehabilitation program on clinical scores and LTP-like plasticity explored using paired associative stimulation (PAS). Synaptic plasticity expression was compared in patients and healthy subjects.

RESULTS

Reduced LTP expression was found in RR-MS patients compared with controls. Exercising RR-MS patients showed a greater amount of LTP expression compared with sedentary patients. In PMS patients, LTP expression was reduced compared with controls and increased after 8 weeks of rehabilitation. In this group of patients, LTP magnitude at baseline predicted the improvement in hand dexterity.

CONCLUSIONS

Both preventive exercise and physical rehabilitation may enhance the expression of LTP-like synaptic plasticity in MS, with potential beneficial effects on disability accumulation.

Genetic regulation of IL-8 influences disease presentation of multiple sclerosis

BACKGROUND

Individual genetic variability may influence the course of multiple sclerosis (MS). The interleukin (IL)-8C>T rs2227306 single nucleotide polymorphism (SNP) regulates IL-8 activity in other clinical conditions; however, its role in MS has never been investigated.

OBJECTIVES

To explore the association between IL-8 SNP rs2227306, cerebrospinal fluid (CSF) IL-8 concentrations, clinical, and radiological characteristics in a group of newly diagnosed MS patients.

METHODS

In 141 relapsing-remitting (RR)-MS patients, rs2227306 polymorphism, CSF levels of IL-8, clinical, and demographical characteristics were determined. In 50 patients, structural magnetic resonance imaging (MRI) measures were also assessed.

RESULTS

An association between CSF IL-8 and Expanded Disability Status Scale (EDSS) at diagnosis was found in our set of patients (r = 0.207, p = 0.014). CSF IL-8 concentrations were significantly higher in patients carrying the T variant of rs2227306 (p = 0.004). In the same group, a positive correlation emerged between IL-8 and EDSS (r = 0.273, p = 0.019). Finally, a negative correlation between CSF levels of IL-8 and cortical thickness emerged in rs2227306T carriers (r = -0.498, p = 0.005).

CONCLUSION

We describe for the first time a role of SNP rs2227306 of IL-8 gene in regulating the expression and the activity of this inflammatory cytokine in MS.

BACE1 influences clinical manifestations and central inflammation in relapsing remitting multiple sclerosis

Neurodegenerative and inflammatory processes influence the clinical course of multiple sclerosis (MS). The β-site amyloid precursor protein cleaving enzyme 1 (BACE1) has been associated with cognitive dysfunction, amyloid deposition and neuroinflammation in Alzheimer's disease. We explored in a group of 50 patients with relapsing-remitting MS the association between the cerebrospinal fluid (CSF) levels of BACE1, clinical characteristics at the time of diagnosis and prospective disability after three-years follow-up. In addition, we assessed the correlations between the CSF levels of BACE 1, amyloid β (Aβ) 1-40 and 1-42, phosphorylated tau (pTau), lactate, and a set of inflammatory and anti-inflammatory molecules. BACE1 CSF levels were correlated positively with depression as measured with Beck Depression Inventory-Second Edition scale, and negatively with visuospatial memory performance evaluated by the Brief Visuospatial Memory Test-Revised. In addition, BACE CSF levels were positively correlated with Bayesian Risk Estimate for MS at onset, and with Expanded Disability Status Scale score assessed three years after diagnosis. Furthermore, a positive correlation was found between BACE1, amyloid β 42/40 ratio (Spearman's r = 0.334, p = 0.018, n = 50), pTau (Spearman's r = 0.304, p = 0.032, n = 50) and lactate concentrations (Spearman's r = 0.361, p = 0.01, n = 50). Finally, an association emerged between BACE1 CSF levels and a group of pro and anti-inflammatory molecules, including interleukin (IL)-4, IL-17, IL-13, IL-9 and interferon-γ. BACE1 may have a role in different key mechanisms such as neurodegeneration, oxidative stress and inflammation, influencing mood, cognitive disorders and disability progression in MS.

Osteopontin Is Associated with Multiple Sclerosis Relapses

BACKGROUND

Osteopontin, an extracellular matrix protein involved in bone remodeling, tissue repair and inflammation, has previously been associated with increased inflammation and neurodegeneration in multiple sclerosis (MS), promoting a worse disease course. Osteopontin is also likely involved in acute MS relapses.

METHODS

In 47 patients with relapsing-remitting MS, we explored the correlation between the time elapsed between the last clinical relapse and lumbar puncture, and the cerebrospinal fluid (CSF) levels of osteopontin and a group of inflammatory cytokines and adipokines such as resistin, plasminogen activator inhibitor-1, osteoprotegerin, interleukin (IL)-1β, IL-2, IL-6 and IL-1 receptor antagonist (IL-1ra). We also analyzed the correlations between CSF levels of osteopontin and the other CSF molecules considered.

RESULTS

Osteopontin CSF concentrations were higher in patients with a shorter time interval between the last clinical relapse and CSF withdrawal. In addition, CSF levels of osteopontin were positively correlated with the proinflammatory cytokines IL-2 and IL-6 and negatively correlated with the anti-inflammatory molecule IL-1ra.

CONCLUSIONS

Our results further suggest the role of osteopontin in acute MS relapses showing that, in proximity to relapses, osteopontin expression in CSF may be increased along with other proinflammatory mediators and correlated with decreased concentrations of anti-inflammatory molecules.

Preventive exercise attenuates IL-2-driven mood disorders in multiple sclerosis

BACKGROUND

Elevated levels of specific proinflammatory molecules in the cerebrospinal fluid (CSF) have been associated with disability progression, enhanced neurodegeneration and higher incidence of mood disorders in people with multiple sclerosis (MS). Studies in animal models of MS suggest that preventive exercise may play an immunomodulatory activity, with beneficial effects on both motor deficits and behavioral alterations. Here we explored the impact of lifestyle physical activity on clinical presentation and associated central inflammation in a large group of newly diagnosed patients with MS. Furthermore, we addressed the causal link between exercise-mediated immunomodulation and mood symptoms in the animal setting.

METHODS

A cross-sectional study was conducted on 235 relapsing-remitting MS patients at the time of the diagnosis. Patients were divided into 3 groups ("sedentary", "lifestyle physical activity" and "exercise") according to the level of physical activity in the six months preceding the evaluation. Patients underwent clinical, neuropsychological and psychiatric evaluation, magnetic resonance imaging and lumbar puncture for diagnostic purposes. The CSF levels of proinflammatory and anti-inflammatory cytokines were analyzed and compared with a group of 80 individuals with non-inflammatory and non-degenerative diseases. Behavioral and electrophysiological studies were carried out in control mice receiving intracerebral injection of IL-2 or vehicle. Behavior was also assessed in mice with experimental autoimmune encephalomyelitis (EAE), animal model of MS, reared in standard (sedentary group) or running wheel-equipped (exercise group) cages.

RESULTS

In exercising MS patients, depression and anxiety were reduced compared to sedentary patients. The CSF levels of the interleukin-2 and 6 (IL-2, IL-6) were increased in MS patients compared with control individuals. In MS subjects exercise was associated with normalized CSF levels of IL-2. In EAE mice exercise started before disease onset reduced both behavioral alterations and striatal IL-2 expression. Notably, a causal role of IL-2 in mood disorders was shown. IL-2 administration in control healthy mice induced anxious- and depressive-like behaviors and impaired type-1 cannabinoid (CB1) receptor-mediated neurotransmission at GABAergic synapses, mimicking EAE-induced synaptic dysfunction.

CONCLUSIONS

Our results indicate an immunomodulatory effect of exercise in MS patients, associated with reduced CSF expression of IL-2, which might result in reduced mood disorders. These data suggest that exercise in the early stages may act as a disease-modifying therapy in MS although further longitudinal studies are needed to clarify this issue.

Interleukin 6 SNP rs1818879 Regulates Radiological and Inflammatory Activity in Multiple Sclerosis

(1) Background: The clinical course of multiple sclerosis (MS) is critically influenced by the expression of different pro-inflammatory and anti-inflammatory cytokines. Interleukin 6 (IL-6) represents a major inflammatory molecule previously associated with exacerbated disease activity in relapsing remitting MS (RR-MS); however, the role of single-nucleotide polymorphisms (SNPs) in the IL-6 gene has not been fully elucidated in MS. (2) Methods: We explored in a cohort of 171 RR-MS patients, at the time of diagnosis, the associations between four IL-6 SNPs (rs1818879, rs1554606, rs1800797, and rs1474347), CSF inflammation, and clinical presentation. (3) Results: Using principal component analysis and logistic regression analysis we identified an association between rs1818879, radiological activity, and a set of cytokines, including the IL-1β, IL-9, IL-10, and IL-13. No significant associations were found between other SNPs and clinical or inflammatory parameters. (4) Conclusions: The association between the rs1818879 polymorphism and subclinical neuroinflammatory activity suggests that interindividual differences in the IL-6 gene might influence the immune activation profile in MS.

The BDNF Val66Met Polymorphism (rs6265) Modulates Inflammation and Neurodegeneration in the Early Phases of Multiple Sclerosis

The clinical course of multiple sclerosis (MS) is critically influenced by the interplay between inflammatory and neurodegenerative processes. The brain-derived neurotrophic factor (BDNF) Val66Met polymorphism (rs6265), one of the most studied single-nucleotide polymorphisms (SNPs), influences brain functioning and neurodegenerative processes in healthy individuals and in several neuropsychiatric diseases. However, the role of this polymorphism in MS is still controversial. In 218 relapsing–remitting (RR)-MS patients, we explored, at the time of diagnosis, the associations between the Val66Met polymorphism, clinical characteristics, and the cerebrospinal fluid (CSF) levels of a large set of pro-inflammatory and anti-inflammatory molecules. In addition, associations between Val66Met and structural MRI measures were assessed. We identified an association between the presence of Met and a combination of cytokines, identified by principal component analysis (PCA), including the pro-inflammatory molecules MCP-1, IL-8, TNF, Eotaxin, and MIP-1b. No significant associations emerged with clinical characteristics. Analysis of MRI measures evidenced reduced cortical thickness at the time of diagnosis in patients with Val66Met. We report for the first time an association between the Val66Met polymorphism and central inflammation in MS patients at the time of diagnosis. The role of this polymorphism in both inflammatory and neurodegenerative processes may explain its complex influence on the MS course.

Multiple sclerosis: Inflammation, autoimmunity and plasticity

In recent years, experimental studies have clarified that immune system influences the functioning of the central nervous system (CNS) in both physiologic and pathologic conditions. The neuro-immune crosstalk plays a crucial role in neuronal development and may be critically involved in mediating CNS response to neuronal damage. Multiple sclerosis (MS) represents a good model to investigate how the immune system regulates neuronal activity. Accordingly, a growing body of evidence has demonstrated that increased levels of pro-inflammatory mediators may significantly impact synaptic mechanisms, influencing overall neuronal excitability and synaptic plasticity expression. In this chapter, we provide an overview of preclinical data and clinical studies exploring synaptic functioning noninvasively with transcranial magnetic stimulation (TMS) in patients with MS. Moreover, we examine how inflammation-driven synaptic dysfunction could affect synaptic plasticity expression, negatively influencing the MS course. Contrasting CSF inflammation together with pharmacologic enhancement of synaptic plasticity and application of noninvasive brain stimulation, alone or in combination with rehabilitative treatments, could improve the clinical compensation and prevent the accumulating deterioration in MS.

Age at Disease Onset Associates With Oxidative Stress, Neuroinflammation, and Impaired Synaptic Plasticity in Relapsing-Remitting Multiple Sclerosis

Age at onset is the main risk factor for disease progression in patients with relapsing-remitting multiple sclerosis (RR-MS). In this cross-sectional study, we explored whether older age is associated with specific disease features involved in the progression independent of relapse activity (PIRA). In 266 patients with RR-MS, the associations between age at onset, clinical characteristics, cerebrospinal fluid (CSF) levels of lactate, and that of several inflammatory molecules were analyzed. The long-term potentiation (LTP)-like plasticity was studied using transcranial magnetic stimulation (TMS). Older age was associated with a reduced prevalence of both clinical and radiological focal inflammatory disease activity. Older patients showed also increased CSF levels of lactate and that of the pro-inflammatory molecules monocyte chemoattractant protein 1 (MCP-1)/CCL2, macrophage inflammatory protein 1-alpha (MIP-1α)/CCL3, and interleukin (IL)-8. Finally, TMS evidenced a negative correlation between age and LTP-like plasticity. In newly diagnosed RR-MS, older age at onset is associated with reduced acute disease activity, increased oxidative stress, enhanced central inflammation, and altered synaptic plasticity. Independently of their age, patients with multiple sclerosis (MS) showing similar clinical, immunological, and neurophysiological characteristics may represent ideal candidates for early treatments effective against PIRA.

Cerebrospinal fluid inflammatory biomarkers predicting interferon-beta response in MS patients

Background and Aims:

Interferon beta (IFNb) is a safe first-line drug commonly used for relapsing-remitting (RR)-MS. Nevertheless, a considerable proportion of patients do not respond to IFNb treatment. Therefore, until now, a number of studies have investigated various markers that could predict the patients who would respond to IFNb therapy. The objective of this study was to identify reliable biomarkers to predict the efficacy of IFNb treatment in MS.

Methods:

In a group of 116 patients with clinically isolated syndrome (CIS) and RR-MS, we explored the association between CSF detectability of a large set of proinflammatory and anti-inflammatory molecules at the time of diagnosis and response to IFNb after the first year of treatment. The absence of clinical relapses, radiological activity and disability progression (NEDA-3) was assessed at the end of 1-year follow up. The results were compared with those obtained in additional groups of CIS and RR-MS patients treated with other first-line drugs (dimethyl fumarate and glatiramer acetate).

Results:

CSF undetectability of macrophage inflammatory protein (MIP)-1α was the main predictor of reaching NEDA-3 status after 1 year of IFNb treatment. Moreover, detectable platelet-derived growth factor (PDGF) was associated with higher probability of reaching NEDA-3. Conversely, no associations with the CSF molecules were found in the two other groups of patients treated either with dimethyl fumarate or with glatiramer acetate.

Conclusion:

MIP-1α and PDGF could potentially represent suitable CSF biomarkers able to predict response to IFNb in MS.

SARS-CoV-2 Transmission and Outcome in Neuro-rehabilitation Patients Hospitalized at Neuroscience Hospital in Italy

ABSTRACT Introduction:  Patients admitted to intensive neurorehabilitation facilities following neurological damage who developed SARS-CoV-2 infection during hospitalization have not yet been reported. Such patients are elderly, with severe disabling neurological syndromes, more likely have significant underlying comorbidities and develop fatal complications during the disease. We reported clinical features, underlying comorbidities, laboratory and radiological findings, treatment and outcome of severely disabled neurological patients with SARS-CoV-2 infection. Methods:  We retrospectively analyzed a group of 14 patients affected by severe neurological damage previously admitted to the Neurorehabilitation Unit of Neuromed Research Institute in Pozzilli, Italy, who developed confirmed COVID-19 during a SARS-CoV-2 outbreak occurred on March, 2020. Results:  One out of 14 patients (7%) died after developing a severe acute respiratory distress. The remaining patients did not present any symptom or laboratory or radiological signs of the disease; neither new neurological deficit nor worsening of the pre-existing clinical manifestations were observed. Thirtheen patients had underlying comorbitidies (93%), the most frequent being hypertension (11 patients, 78.5%) and diabetes mellitus type II (7 patients, 50%). Long before infection, all patients were already under anticoagulant therapy with enoxaparin. Conclusions:  In 13 out of 14 patients, the infection was asymptomatic; this is particularly intriguing considering their severe neurological clinical profile. According to the pivotal role played by inflammation and activation of blood coagulation in the pathogenesis of COVID-19, the anti-inflammatory and anticoagulant properties of enoxaparin, administered much earlier and during infection, could have favored an extremely benign disease course in these patients at high risk of poor outcome. Keywords: SARS CoV 2, neurological patients, neurological damage, Infection, Coronavirus    

Inflammation and Corticospinal Functioning in Multiple Sclerosis: A TMS Perspective

Transcranial magnetic stimulation (TMS) has been employed in multiple sclerosis (MS) to assess the integrity of the corticospinal tract and the corpus callosum and to explore some physiological properties of the motor cortex. Specific alterations of TMS measures have been strongly associated to different pathophysiological mechanisms, particularly to demyelination and neuronal loss. Moreover, TMS has contributed to investigate the neurophysiological basis of MS symptoms, particularly those not completely explained by conventional structural damage, such as fatigue. However, variability existing between studies suggests that alternative mechanisms should be involved. Knowledge of MS pathophysiology has been enriched by experimental studies in animal models (i.e., experimental autoimmune encephalomyelitis) demonstrating that inflammation alters synaptic transmission, promoting hyperexcitability and neuronal damage. Accordingly, TMS studies have demonstrated an imbalance between cortical excitation and inhibition in MS. In particular, cerebrospinal fluid concentrations of different proinflammatory and anti-inflammatory molecules have been associated to corticospinal hyperexcitability, highlighting that inflammatory synaptopathy may represent a key pathophysiological mechanism in MS. In this perspective article, we discuss whether corticospinal excitability alterations assessed with TMS in MS patients could be useful to explain the pathophysiological correlates and their relationships with specific MS clinical characteristics and symptoms. Furthermore, we discuss evidence indicating that, in MS patients, inflammatory synaptopathy could be present since the early phases, could specifically characterize relapses, and could progressively increase during the disease course.

IL-6 in the Cerebrospinal Fluid Signals Disease Activity in Multiple Sclerosis

Specific proinflammatory and anti-inflammatory molecules could represent useful cerebrospinal fluid (CSF) biomarkers to predict the clinical course of multiple sclerosis (MS). The proinflammatory molecule interleukin (IL)-6 has been investigated in the pathophysiology of MS and has been associated in previous smaller studies to increased disability and disease activity. Here, we wanted to further address IL-6 as a possible CSF biomarker of MS by investigating its detectability in a large cohort of 534 MS patients and in 103 individuals with other non-inflammatory neurological diseases. In these newly diagnosed patients, we also explored correlations between IL-6 detectability, MS phenotypes, and disease characteristics. We found that IL-6 was more frequently detectable in the CSF of MS patients compared with their control counterparts as significant differences emerged between patients with Clinically isolated syndrome (CIS), Relapsing–remitting (RR), and secondary progressive and primary progressive MS compared to non-inflammatory controls. IL-6 was equally present in the CSF of all MS phenotypes. In RR MS patients, IL-6 detectability was found to signal clinically and/or radiologically defined disease activity, among all other clinical characteristics. Our results add further evidence that CSF proinflammatory cytokines could be useful for the identification of those MS patients who are prone to increased disease activity. In particular, IL-6 could represent an interesting prognostic biomarker of MS, as also demonstrated in other diseases where CSF IL-6 was found to identify patients with worse disease severity.

A Novel Tool for the Early Identification of Frailty in Elderly People: The Application in Primary Care Settings

BACKGROUND

Frailty is a pre-disability condition in older persons providing a challenge to Health-Care Systems. Systematic reviews highlight the absence of a gold-standard for its identification. However, an approach based on initial screening by the General Practitioner (GP) seems particularly useful. On these premises, a 9-item Sunfrail Checklist (SC), was developed by a multidisciplinary group, in the context of European Sunfrail Project, and tested in the Community.

OBJECTIVES

- to measure the concordance between the judgments of frailty (criterion-validity): the one formulated by the GP, using the SC, and the one subsequently expressed by a Comprehensive Geriatric Assessment Team (CGA-Team); - to determine the construct-validity through the correspondence between some checklist items related to the 3 domains (physical, cognitive and social) and the three tools used by the CGA-Team; - to measure the instrument's performance in terms of positive predictive value (PPV) and negative predictive value (NPV).

DESIGN

Cross-sectional study, with a final sample-size of 95 subjects.

SETTING

Two Community-Health Centers of Parma, Italy.

PARTICIPANTS

Subjects aged 75 years old or more, with no disability and living in the community.

MEASUREMENTS

We compared the screening capacity of the GP using the SC to that one of CGA-Team based on three tests: 4-meter Gait-Speed, Mini-Mental State Examination and Loneliness Scale.

RESULTS

95 subjects (51 women), with a mean age of 81±4 years were enrolled. According to GPs 34 subjects were frail; the CGA-Team expressed a frailty judgment on 26 subjects. The criterion-validity presented a Cohen's k of 0.353. Construct-validity was also low, with a maximum contingency-coefficient of 0.19. The analysis showed a PPV of 58.1% and a NPV equal to 84.6%.

CONCLUSIONS

Our data showed a low agreement between the judgements of GP performed by SC and CGA-Team. However, the good NPV suggests the applicability of SC for screening activities in primary-care.

Practice-dependent motor cortex plasticity is reduced in non-disabled multiple sclerosis patients

OBJECTIVES

Skill acquisition after motor training involves synaptic long-term potentiation (LTP) in primary motor cortex (M1). In multiple sclerosis (MS), LTP failure ensuing from neuroinflammation could contribute to worsen clinical recovery. We therefore addressed whether practice-dependent plasticity is altered in MS.

METHODS

Eighteen relapsing-remitting (RR)-MS patients and eighteen healthy controls performed 600 fast abductions of index finger in 30 blocks of 20 movements. Before and after practice, transcranial magnetic stimulation (TMS) was delivered over the hot spot of the trained first dorsal interosseous muscle. Movements kinematics, measures of cortical excitability, and the input/output curves of motor evoked potentials (MEPs) were assessed.

RESULTS

Kinematic variables of movement improved with practice in patients and controls to a similar extent, although patients showed lower MEPs amplitude increase after practice. Practice did not change the difference in resting motor threshold values observed between patients and controls, nor did modulate short-interval intracortical inhibition. Clinical/radiological characteristics were not associated to practice-dependent effects.

CONCLUSIONS

Practice-induced reorganization of M1 is altered in non-disabled RR-MS patients, as shown by impaired MEPs modulation after motor learning.

SIGNIFICANCE

These findings suggest that in RR-MS physiological mechanisms of practice-dependent plasticity are altered.

Interleukin-6 Disrupts Synaptic Plasticity and Impairs Tissue Damage Compensation in Multiple Sclerosis

Background: Synaptic plasticity helps in reducing the clinical expression of brain damage and represents a useful mechanism to compensate the negative impact of new brain lesions in multiple sclerosis (MS). Inflammation, altering synaptic plasticity, could negatively influence the disease course in relapsing-remitting MS (RR-MS). Objective: In the present study, we explored whether interleukin (IL)-6, a major proinflammatory cytokine involved in MS pathogenesis, alters synaptic plasticity and affects the ability to compensate for ongoing brain damage. Methods: The effect of IL-6 incubation on long-term potentiation (LTP) induction was explored in vitro, in mice hippocampal slices. We also explored the correlation between the cerebrospinal fluid (CSF) levels of this cytokine and the LTP-like effect induced by the paired associative stimulation (PAS) in a group of RR-MS patients. Finally, we examined the correlation between the CSF levels of IL-6 at the time of diagnosis and the prospective disease activity in a cohort of 150 RR-MS patients. Results: In vitro LTP induction was abolished by IL-6. Consistently, in patients with MS, a negative correlation emerged between IL-6 CSF concentrations and the effect of PAS. In MS patients, longer disease duration before diagnosis was associated with higher IL-6 CSF concentrations. In addition, elevated CSF levels of IL-6 were associated with greater clinical expression of new inflammatory brain lesions, unlike in patients with low or absent IL-6 concentrations, who had a better disease course. Conclusions: IL-6 interfering with synaptic plasticity mechanisms may impair the ability to compensate the clinical manifestation of new brain lesions in RR-MS patients.

Obesity worsens central inflammation and disability in multiple sclerosis

BACKGROUND

Previous studies evidenced a link between metabolic dysregulation, inflammation, and neurodegeneration in multiple sclerosis (MS).

OBJECTIVES

To explore whether increased adipocyte mass expressed as body mass index (BMI) and increased serum lipids influence cerebrospinal fluid (CSF) inflammation and disease severity.

METHODS

In this cross-sectional study, 140 consecutive relapsing-remitting (RR)-MS patients underwent clinical assessment, BMI evaluation, magnetic resonance imaging scan, and blood and CSF collection before any specific drug treatment. The CSF levels of the following cytokines, adipocytokines, and inflammatory factors were measured: interleukin (IL)-6, IL-13, granulocyte macrophage colony-stimulating factor, leptin, ghrelin, osteoprotegerin, osteopontin, plasminogen activator inhibitor-1, resistin, and Annexin A1. Serum levels of triglycerides, total cholesterol (TC), and high-density lipoprotein cholesterol (HDL-C) were assessed.

RESULTS

A positive correlation emerged between BMI and Expanded Disability Status Scale score. Obese RR-MS patients showed higher clinical disability, increased CSF levels of the proinflammatory molecules IL-6 and leptin, and reduced concentrations of the anti-inflammatory cytokine IL-13. Moreover, both the serum levels of triglycerides and TC/HDL-C ratio showed a positive correlation with IL-6 CSF concentrations.

CONCLUSION

Obesity and altered lipid profile are associated with exacerbated central inflammation and higher clinical disability in RR-MS at the time of diagnosis. Increased adipocytokines and lipids can mediate the negative impact of high adiposity on RR-MS course.

Transient Receptor Potential Vanilloid 1 Modulates Central Inflammation in Multiple Sclerosis

Introduction: Disease course of multiple sclerosis (MS) is negatively influenced by proinflammatory molecules released by activated T and B lymphocytes and local immune cells. The endovanilloid system plays different physiological functions, and preclinical data suggest that transient receptor potential vanilloid type 1 (TRPV1) could modulate neuroinflammation in this disorder.

Methods: The effect of TRPV1 activation on the release of two main proinflammatory cytokines, tumor necrosis factor (TNF) and interleukin (IL)-6, was explored in activated microglial cells. Furthermore, in a group of 132 MS patients, the association between the cerebrospinal fluid (CSF) levels of TNF and IL-6 and a single nucleotide polymorphisms (SNP) influencing TRPV1 protein expression and function (rs222747) was assessed.

Results: In in vitro experiments, TRPV1 stimulation by capsaicin significantly reduced TNF and IL-6 release by activated microglial cells. Moreover, the anti-inflammatory effect of TRPV1 activation was confirmed by another TRPV1 agonist, the resiniferatoxin (RTX), whose effects were significantly inhibited by the TRPV1 antagonist, 5-iodoresiniferatoxin (5-IRTX). Vice versa, BV2 pre-treatment with 5-IRTX increased the inflammatory response induced by LPS. Moreover, in MS patients, a significant association emerged between TRPV1 SNP rs222747 and CSF TNF levels. In particular, the presence of a G allele, known to result in increased TRPV1 protein expression and function, was associated to lower CSF levels of TNF.

Conclusions: Our results indicate that TRPV1 influences central inflammation in MS by regulating cytokine release by activated microglial cells. The modulation of the endovanilloid system may represent a useful approach to contrast neuroinflammation in MS.

Exploiting the Multifaceted Effects of Cannabinoids on Mood to Boost Their Therapeutic Use Against Anxiety and Depression

The endocannabinoid system (ECS) has been recently recognized as a prominent promoter of the emotional homeostasis, mediating the effects of different environmental signals including rewarding and stressing stimuli. The ECS modulates the rewarding effects of environmental stimuli, influencing synaptic transmission in the dopaminergic projections to the limbic system, and mediates the neurophysiological and behavioral consequences of stress. Notably, the individual psychosocial context is another key element modulating the activity of the ECS. Finally, inflammation represents an additional factor that could alter the cannabinoid signaling in the CNS inducing a "sickness behavior," characterized by anxiety, anhedonia, and depressive symptoms. The complex influences of the ECS on both the environmental and internal stimuli processing, make the cannabinoid-based drugs an appealing option to treat different psychiatric conditions. Although ample experimental evidence shows beneficial effects of ECS modulation on mood, scarce clinical indication limits the use of cannabis-based treatments. To better define the possible clinical indications of cannabinoid-based drugs in psychiatry, a number of issues should be better addressed, including genetic variability and psychosocial factors possibly affecting the individual response. In particular, better knowledge of the multifaceted effects of cannabinoids could help to understand how to boost their therapeutic use in anxiety and depression treatment.

Delayed treatment of MS is associated with high CSF levels of IL-6 and IL-8 and worse future disease course

BACKGROUND

Clinical deterioration of relapsing-remitting MS (RR-MS) patients reflects not only the number and severity of overt inflammatory and demyelinating episodes, but also subtle central damage caused by persistent exposure to inflammatory molecules.

OBJECTIVE

To explore the correlation between levels of CSF inflammatory molecules at the time of diagnosis and both demographic and clinical characteristics of a large sample of RR-MS patients, as well as the predictive value of cytokine levels on their prospective disease course.

METHODS

In 205 patients diagnosed with RR-MS, we measured at the time of diagnosis the CSF levels of inflammatory molecules. Clinical and MRI evaluation was collected at the time of CSF withdrawal and during a median follow-up of 3 years.

RESULTS

The time interval between the first anamnestic episode of focal neurological dysfunction and RR-MS diagnosis was the main factor associated with high CSF levels of IL-6 and IL-8. Furthermore, elevated CSF levels of these cytokines correlated with enhanced risk of clinical and radiological disease reactivation, switch to second-line treatments, and with disability progression in the follow-up.

CONCLUSIONS

Delayed diagnosis and treatment initiation are associated with higher CSF levels of IL-6 and IL-8 in RR-MS, leading to worsening disease course and poor response to treatments.

Platelet-derived growth factor predicts prolonged relapse-free period in multiple sclerosis

Background

In the early phases of relapsing-remitting multiple sclerosis (RR-MS), a clear correlation between brain lesion load and clinical disability is often lacking, originating the so-called clinico-radiological paradox. Different factors may contribute to such discrepancy. In particular, synaptic plasticity may reduce the clinical expression of brain damage producing enduring enhancement of synaptic strength largely dependent on neurotrophin-induced protein synthesis. Cytokines released by the immune cells during acute inflammation can alter synaptic transmission and plasticity possibly influencing the clinical course of MS. In addition, immune cells may promote brain repair during the post-acute phases, by secreting different growth factors involved in neuronal and oligodendroglial cell survival. Platelet-derived growth factor (PDGF) is a neurotrophic factor that could be particularly involved in clinical recovery. Indeed, PDGF promotes long-term potentiation of synaptic activity in vitro and in MS and could therefore represent a key factor improving the clinical compensation of new brain lesions. The aim of the present study is to explore whether cerebrospinal fluid (CSF) PDGF concentrations at the time of diagnosis may influence the clinical course of RR-MS.

Methods

At the time of diagnosis, we measured in 100 consecutive early MS patients the CSF concentrations of PDGF, of the main pro- and anti-inflammatory cytokines, and of reliable markers of neuronal damage. Clinical and radiological parameters of disease activity were prospectively collected during follow-up.

Results

CSF PDGF levels were positively correlated with prolonged relapse-free survival. Radiological markers of disease activity, biochemical markers of neuronal damage, and clinical parameters of disease progression were instead not influenced by PDGF concentrations. Higher CSF PDGF levels were associated with an anti-inflammatory milieu within the central nervous system.

Conclusions

Our results suggest that PDGF could promote a more prolonged relapse-free period during the course of RR-MS, without influencing inflammation reactivation and inflammation-driven neuronal damage and likely enhancing adaptive plasticity.

Remodeling Functional Connectivity in Multiple Sclerosis: A Challenging Therapeutic Approach

Neurons in the central nervous system are organized in functional units interconnected to form complex networks. Acute and chronic brain damage disrupts brain connectivity producing neurological signs and/or symptoms. In several neurological diseases, particularly in Multiple Sclerosis (MS), structural imaging studies cannot always demonstrate a clear association between lesion site and clinical disability, originating the "clinico-radiological paradox." The discrepancy between structural damage and disability can be explained by a complex network perspective. Both brain networks architecture and synaptic plasticity may play important roles in modulating brain networks efficiency after brain damage. In particular, long-term potentiation (LTP) may occur in surviving neurons to compensate network disconnection. In MS, inflammatory cytokines dramatically interfere with synaptic transmission and plasticity. Importantly, in addition to acute and chronic structural damage, inflammation could contribute to reduce brain networks efficiency in MS leading to worse clinical recovery after a relapse and worse disease progression. These evidence suggest that removing inflammation should represent the main therapeutic target in MS; moreover, as synaptic plasticity is particularly altered by inflammation, specific strategies aimed at promoting LTP mechanisms could be effective for enhancing clinical recovery. Modulation of plasticity with different non-invasive brain stimulation (NIBS) techniques has been used to promote recovery of MS symptoms. Better knowledge of features inducing brain disconnection in MS is crucial to design specific strategies to promote recovery and use NIBS with an increasingly tailored approach.

Amyloid-β Homeostasis Bridges Inflammation, Synaptic Plasticity Deficits and Cognitive Dysfunction in Multiple Sclerosis

Cognitive deficits are frequently observed in multiple sclerosis (MS), mainly involving processing speed and episodic memory. Both demyelination and gray matter atrophy can contribute to cognitive deficits in MS. In recent years, neuroinflammation is emerging as a new factor influencing clinical course in MS. Inflammatory cytokines induce synaptic dysfunction in MS. Synaptic plasticity occurring within hippocampal structures is considered as one of the basic physiological mechanisms of learning and memory. In experimental models of MS, hippocampal plasticity is profoundly altered by proinflammatory cytokines. Although mechanisms of inflammation-induced hippocampal pathology in MS are not completely understood, alteration of Amyloid-β (Aβ) metabolism is emerging as a key factor linking together inflammation, synaptic plasticity and neurodegeneration in different neurological diseases. We explored the correlation between concentrations of Aβ_1–42 and the levels of some proinflammatory and anti-inflammatory cytokines (interleukin-1β (IL-1β), IL1-ra, IL-8, IL-10, IL-12, tumor necrosis factor α (TNFα), interferon γ (IFNγ)) in the cerebrospinal fluid (CSF) of 103 remitting MS patients. CSF levels of Aβ_1–42 were negatively correlated with the proinflammatory cytokine IL-8 and positively correlated with the anti-inflammatory molecules IL-10 and interleukin-1 receptor antagonist (IL-1ra). Other correlations, although noticeable, were either borderline or not significant. Our data show that an imbalance between proinflammatory and anti-inflammatory cytokines may lead to altered Aβ homeostasis, representing a key factor linking together inflammation, synaptic plasticity and cognitive dysfunction in MS. This could be relevant to identify novel therapeutic approaches to hinder the progression of cognitive dysfunction in MS.

Nerve growth factor is elevated in the CSF of patients with multiple sclerosis and central neuropathic pain

Central neuropathic pain (CNP) is common and disabling among patients with multiple sclerosis (MS). The pathological mechanisms underlying CNP in MS are not well understood. We explored whether NGF is implicated in the pathogenesis of CNP in MS. We measured NGF concentration in the CSF of 73 patients affected by MS, 15 with and 58 without CNP and 14 controls. We found increased levels of NGF in the CSF of patients with CNP compared to patients without and to controls. This finding supports the hypothesis that NGF plays a role in MS related CNP.

Can pharmacological manipulation of LTP favor the effects of motor rehabilitation in multiple sclerosis?

Background:

Synaptic plasticity, the basic mechanism of clinical recovery after brain lesion, can also remarkably influence the clinical course of multiple sclerosis (MS). Physical rehabilitation represents the main treatment option to promote synaptic long-term potentiation (LTP) and to enhance spontaneous recovery of neurological deficits.

Objectives:

To overview the role of pharmacological treatment and physical rehabilitation in modulating LTP and enhancing clinical recovery in MS.

Results:

Drug-induced LTP enhancement can be effectively used to promote functional recovery, alone or combined with rehabilitation. Also, as inflammatory cytokines alter synaptic transmission and plasticity in MS, pharmacological resolution of inflammation can positively influence clinical recovery. Finally, physical exercise could be an independent factor able to preserve or enhance LTP reserve both influencing signaling pathways involved in plasticity induction and maintenance, and decreasing inflammation.

Future directions:

Better knowledge of LTP determinants may be useful to design specific strategies to promote recovery after a relapse and to reduce the progressive neurological deterioration in MS patients.

Cannabinoids in Parkinson's Disease

The endocannabinoid system plays a regulatory role in a number of physiological processes and has been found altered in different pathological conditions, including movement disorders. The interactions between cannabinoids and dopamine in the basal ganglia are remarkably complex and involve both the modulation of other neurotransmitters (γ-aminobutyric acid, glutamate, opioids, peptides) and the activation of different receptors subtypes (cannabinoid receptor type 1 and 2). In the last years, experimental studies contributed to enrich this scenario reporting interactions between cannabinoids and other receptor systems (transient receptor potential vanilloid type 1 cation channel, adenosine receptors, 5-hydroxytryptamine receptors). The improved knowledge, adding new interpretation on the biochemical interaction between cannabinoids and other signaling pathways, may contribute to develop new pharmacological strategies. A number of preclinical studies in different experimental Parkinson's disease (PD) models demonstrated that modulating the cannabinoid system may be useful to treat some motor symptoms. Despite new cannabinoid-based medicines have been proposed for motor and nonmotor symptoms of PD, so far, results from clinical studies are controversial and inconclusive. Further clinical studies involving larger samples of patients, appropriate molecular targets, and specific clinical outcome measures are needed to clarify the effectiveness of cannabinoid-based therapies.

Reliability and repeatability of testing visual evoked potential habituation in migraine: A blinded case–control study

Background

Many studies have shown that migraine patients have an interictal habituation deficit of visual evoked potentials (VEPs). Some discordant results were attributed to non-blinded analyses and a lack of repeatability.

Aims

In this study, we compared blinded and non-blinded analyses of the same recordings and assessed test–retest repeatability.

Methods

VEP recordings of 25 healthy volunteers (HVs) and 78 episodic migraine patients (EMs; 52 interictal, 26 ictal) were analysed by two investigators, one of whom was blinded to diagnosis and headache phase. Twelve HVs and nine EMs had two recordings for test repeatability.

Results

In both blinded and non-blinded analyses, VEP habituation was normal in HVs and EMs during an attack, but deficient in EMs interictally. Intra-individual habituation percentages were highly correlated in two recordings separated by ≥7 days.

Conclusions

The studies showing a VEP habituation deficit in migraineurs between attacks are unlikely to be biased by non-blinding analysis or poor repeatability.

Correlation between habituation of visual-evoked potentials and magnetophosphene thresholds in migraine: A case-control study

Introduction

In migraine most studies report an interictal deficit of habituation of visual-evoked potentials (VEP-hab) and reduced thresholds for phosphene induction (PT) by transcranial magnetic stimulation (TMS). We searched for a possible correlation between VEP-hab and PT in migraine patients and healthy controls to test whether they reflect the same pathophysiological abnormality.

Methods

We assessed PT and VEP-hab measured as the percentage change of N1/P1 amplitude over six blocks of 100 responses in 15 healthy volunteers (HV) and in 13 episodic migraineurs without aura (MO) between attacks. Results were compared using Mann-Whitney U test. Interrelationships were examined using Spearman's correlation.

Results

In MO patients VEP-hab was reduced compared to HV ( p = 0.001), while PT were not significantly different between HV and MO. There was no correlation between PT and VEP-hab in either group of participants.

Conclusions

We confirm that in interictal migraine VEP habituation is deficient, but magnetophosphene threshold normal. VEP-hab and PT were not correlated with each other in healthy controls or in migraineurs. This finding suggests that they index different facets of cortical excitability in migraine, i.e. a punctual normal measure of the cortical activation threshold for PT and a dynamic response pattern to repeated stimuli for VEP habituation.

Congenital Mirror Movements in a New Italian Family

Mirror movements (MMs) occur on the contralateral side of a limb being used intentionally. Because few families with congenital MMs and no other neurological signs have been reported, the underlying mechanisms of MMs are still not entirely clear. We report on the clinical, genetic, neurophysiological and neuroimaging findings of 10 of 26 living members of a novel four-generation family with congenital MMs. DCC and RAD51 were sequenced in affected members of the family. Five of the ten subjects with MMs underwent neurophysiological and neuroimaging evaluations. The neurophysiological evaluation consisted of electromyographic (EMG) mirror recordings, investigations of corticospinal excitability, and analysis of interhemispheric inhibition using transcranial magnetic stimulation techniques. The neuroimaging evaluation included functional MRI during finger movements. Eight (all females) of the ten members examined presented MMs of varying degrees at the clinical assessment. Transmission of MMs appears to have occurred according to an autosomal-dominant fashion with variable expression. No mutation in DCC or RAD51 was identified. EMG mirror activity was higher in MM subjects than in healthy controls. Short-latency interhemispheric inhibition was reduced in MM subjects. Ipsilateral motor-evoked potentials were detectable in the most severe case. The neuroimaging evaluation did not disclose any significant abnormalities in MM subjects. The variability of the clinical features of this family, and the lack of known genetic abnormalities, suggests that MMs are heterogeneous disorders. The pathophysiological mechanisms of MMs include abnormalities of transcallosal inhibition and corticospinal decussation.

Correlation between cortical plasticity, motor learning and BDNF genotype in healthy subjects

There is good evidence that synaptic plasticity in human motor cortex is involved in behavioural motor learning; in addition, it is now possible to probe mechanisms of synaptic plasticity using a variety of transcranial brain-stimulation protocols. Interactions between these protocols suggest that they both utilise common mechanisms. The aim of the present experiments was to test how well responsiveness to brain-stimulation protocols and behavioural motor learning correlate with each other in a sample of 21 healthy volunteers. We also examined whether any of these measures were influenced by the presence of a Val66Met polymorphism in the BDNF gene since this is another factor that has been suggested to be able to predict response to tests of synaptic plasticity. In 3 different experimental sessions, volunteers underwent 5-Hz rTMS, intermittent theta-burst stimulation (iTBS) and a motor learning task. Blood samples were collected from each subject for BDNF genotyping. As expected, both 5-Hz rTMS and iTBS significantly facilitated MEPs. Similarly, as expected, kinematic variables of finger movement significantly improved during the motor learning task. Although there was a significant correlation between the effect of iTBS and 5-Hz rTMS, there was no relationship in each subject between the amount of TMS-induced plasticity and the increase in kinematic variables during motor learning. Val66Val and Val66Met carriers did not differ in their response to any of the protocols. The present results emphasise that although some TMS measures of cortical plasticity may correlate with each other, they may not always relate directly to measures of behavioural learning. Similarly, presence of the Val66Met BDNF polymorphism also does not reliably predict responsiveness in small groups of individuals. Individual success in behavioural learning is unlikely to be closely related to any single measure of synaptic plasticity.

Theta-burst stimulation over primary motor cortex degrades early motor learning

Theta-burst stimulation (TBS) is currently used for inducing long-lasting changes in primary motor cortex (M1) excitability. More information is needed on how M1 is involved in early motor learning (practice-related improvement in motor performance, motor retention and motor consolidation). We investigated whether inhibitory continuous TBS (cTBS) is an effective experimental approach for modulating early motor learning of a simple finger movement in healthy humans. In a short task, 11 subjects practised 160 movements, and in a longer task also testing motor consolidation ten subjects practised 600 movements. During both experiments subjects randomly received real or sham cTBS over the left M1. Motor evoked potentials were tested at baseline and 7 min after cTBS. In the 160-movement experiment to test motor retention, 20 movements were repeated 30 min after motor practice ended. In the 600-movement experiment motor retention was assessed 15 and 30 min after motor practice ended, motor consolidation was tested by performing 20 movements 24 h after motor practice ended. Kinematic variables - movement amplitude, peak velocity and peak acceleration - were measured. cTBS significantly reduced the practice-related improvement in motor performance of finger movements in the experiment involving 160 movements and in the first part of the experiment involving 600 movements. After cTBS, peak velocity and peak acceleration of the 20 movements testing motor retention decreased whereas those testing motor consolidation remained unchanged. cTBS over M1 degrades practice-related improvement in motor performance and motor retention, but not motor consolidation of a voluntary finger movement.

Dopamine influences primary motor cortex plasticity and dorsal premotor-to-motor connectivity in Parkinson's disease

We investigated abnormal premotor to motor (PMd-to-M1) connectivity in Parkinson's disease (PD) with repetitive transcranial magnetic stimulation (rTMS). We studied 28 patients off and on dopaminergic therapy and 28 healthy subjects. We delivered 5 Hz rTMS over M1 before and after conditioning PMd with 5 Hz rTMS. In healthy subjects, motor-evoked potentials (MEPs) elicited by M1-rTMS were facilitated and PMd-rTMS left MEPs unchanged. In patients, before PMd-rTMS, M1-rTMS induced no MEP facilitation, whereas after PMd-rTMS, it significantly facilitated MEPs only when patients were on therapy. In the second experiment, we delivered M1-rTMS under 3 different attention-demanding tasks: eyes closed, attention directed to the stimulated hand, and attention directed to the nonstimulated hand. In healthy subjects, a more pronounced MEP facilitation was present when subjects directed attention to the stimulated hand. In patients, the MEP facilitation was present when attention was directed to the stimulated hand only when patients were on therapy. Finally, we delivered M1-rTMS in patients on therapy while they were looking at the stimulated hand, before and after 1 Hz PMd-rTMS. PMd-rTMS reduced the attention-induced MEP facilitation. We conclude that in addition to abnormal M1 plasticity, the reduced MEP facilitation in PD also reflects altered PMd-to-M1 connectivity.

Phasic voluntary movements reverse the aftereffects of subsequent theta-burst stimulation in humans

Theta-burst stimulation (TBS) is a technique that elicits long-lasting changes in the excitability of human primary motor cortex (M1). Tonic contraction of the target muscle modifies the aftereffects of TBS, whereas interactions between phasic muscle contraction and the aftereffects of TBS are unknown. In this paper, we investigated whether phasic voluntary movements influence TBS-induced changes in M1 excitability. We examined whether a brief sequence of phasic finger movements performed by healthy humans before both intermittent TBS (iTBS) and continuous TBS (cTBS) influences TBS-induced aftereffects. Ten healthy subjects underwent iTBS and cTBS. To evaluate the TBS-induced aftereffects on M1 excitability, single TMS pulses were given over the FDI motor area before (T0) and 5 (T1), 15 (T2), and 30 min (T3) after TBS. To find out whether finger movements influenced the TBS-induced aftereffects, we tested motor-evoked potentials (MEPs) size by single TMS pulses at T0, immediately after movements, and at T1-T3. We also measured the kinematic variables mean amplitude and mean peak velocity of the movements. When no phasic voluntary movements preceded TBS, iTBS elicited facilitatory and cTBS elicited inhibitory aftereffects on MEP size. Conversely, movements performed before TBS elicited significant changes in the direction of the TBS-induced aftereffects. iTBS produced inhibitory instead of facilitatory aftereffects and cTBS produced facilitatory instead of inhibitory aftereffects. Finger movements alone had no effects on MEPs size tested with single-pulse TMS. Peripheral electrical stimulation had no effect on iTBS-induced aftereffects. Repeated phasic finger movements interfere with TBS-induced aftereffects probably by modulating mechanisms of brain metaplasticity.

Effects of unilateral subthalamic deep brain stimulation on contralateral arm sequential movements in Parkinson's disease

In Parkinson's disease, unilateral deep brain stimulation (DBS) of the subthalamic nucleus (STN), unlike bilateral stimulation, excludes ipsilateral confounding effects so that the contralateral effects of DBS on motor performance can be investigated alone. Because no kinematic study has yet investigated how unilateral STN-DBS affects the performance of a contralateral fast sequential motor act, we performed a kinematic analysis of the movement duration, switching time and spatial accuracy of a motor arm sequence in 10 parkinsonian patients. Patients were studied without dopaminergic therapy and when they were OFF and ON unilateral STN-DBS. We found that unilateral STN-DBS significantly improved movement time of a motor sequence and the switching time from one sequential step to the next, whereas accuracy deteriorated. We conclude that unilateral STN-DBS improves the performance of contralateral sequential arm movements in patients with Parkinson's disease.

Attention influences the excitability of cortical motor areas in healthy humans

We investigated whether human attentional processes influence the size of the motor evoked potentials (MEP) facilitation and the duration of the cortical silent period (CSP) elicited by high-frequency repetitive transcranial magnetic stimulation (rTMS). In healthy subjects we assessed the effects of 5 Hz-rTMS, delivered in trains of 10 stimuli at suprathreshold intensity over the hand motor area, on the MEP size and CSP duration in different attention-demanding conditions: "relaxed," "target hand," and "non-target hand" condition. We also investigated the inhibitory effects of 1 Hz-rTMS conditioning to the premotor cortex on the 5 Hz-rTMS induced MEP facilitation. F-waves evoked by ulnar nerve stimulation were also recorded. rTMS trains elicited a larger MEP size facilitation when the subjects looked at the target hand whereas the increase in CSP duration during rTMS remained unchanged during the three attention-demanding conditions. The conditioning inhibitory stimulation delivered to the premotor cortex decreased the MEP facilitation during the "target hand" condition, leaving the MEP facilitation during the other conditions unchanged. None of the attentional conditions elicited changes in the F wave. In healthy subjects attentional processes influence the size of the MEP facilitation elicited by high-frequency rTMS and do so through premotor-to-motor connections.

Effects of 5 Hz subthreshold magnetic stimulation of primary motor cortex on fast finger movements in normal subjects

We evaluated the effects of high-frequency repetitive transcranial magnetic stimulation (rTMS) on motor performance and motor learning of a rapid index finger movement. Two groups of healthy right-handed subjects underwent either "real" rTMS (1800 stimuli over the first dorsal interosseous (FDI) muscle hot spot given at 5 Hz and intensity of 90% of resting motor threshold-RMT) or "sham" stimulation. Both groups performed 60 rapid abductions of the right index finger before and after rTMS. The kinematic variables measured were amplitude, duration, peak velocity and peak acceleration. We also evaluated RMT and motor-evoked potential (MEP) amplitude before, 5 and 30 min after rTMS. In both groups practice significantly increased peak velocity, peak acceleration and amplitude and decreased movement duration independently from the type of intervention ("real" and "sham"). "Real" rTMS significantly increased cortical excitability as measured by MEP amplitude whereas "sham" rTMS did not. In our study, 5 Hz rTMS failed to improve either the motor performance or the motor learning of a rapid index-finger abduction despite the increase in cortical excitability of the primary motor cortex. Since motor behaviour engages a distributed cortical and subcortical neuronal network, excitatory conditioning of the primary motor cortex is probably not sufficient to influence the behavioural output.

Early predictors of intractability in childhood epilepsy: a community-based case-control study in Copparo, Italy

OBJECTIVES

To identify early predictors of intractability in childhood and adolescence epilepsy.

MATERIALS AND METHODS

We carried out a community-based case-control study using the incidence cohort of epileptic patients living in the district of Copparo, in the province of Ferrara, Italy. The comparative study was performed in 31 cases and 95 controls. Cases were patients who averaged at least 1 unprovoked seizure per month during an observational period of at least 2 years. Controls were subjects having achieved remission for at least 5 years regardless of current therapy.

RESULTS

Onset at age <1 year, remote symptomatic etiology and high frequency of seizures before therapy were found to be independent early predictors of intractability.

CONCLUSION

Our study suggested that the risk of developing intractable epilepsy may, to some extent, be predicted at the time of initial diagnosis in children with early-onset epilepsy of remote symptomatic etiology, especially if seizure propensity is initially high.