I Riflessi del tronco encefalico nella malattia di Parkinson: uno studio clinico e neurofisiologico

Recent works have highlighted the rule of brainstem structures in the pathological spread of Parkinson’s Disease (PD). Vestibular Evoked Myogenic Potentials (VEMPs) are a battery of reflexes providing information on a large portion of the brainstem. Aim of the study is to test the VEMPs battery, namely Vestibulo-Ocular Reflex (VOR), Vestibulo-Masseter Reflex (VMR) and Vestibulo-Ocular Reflex (VOR) in a cohort of PD patients and age-matched healthy controls and to correlate them with presence of symptoms ascribable to brainstem dysfunction. 19 PD patients and 15 healthy controls performed the VEMPs battery, and PD patients only underwent a series of clinical scales for evaluation of sleep disorders and REM sleep behavior disorder (ESS, PDSS and RBD-SQ scale), postural instability (MiniBESTest) and depression (GDS). VEMPs were significantly impaired in patients compared to controls with absence as the main alteration; more rostral VEMPs were most involved (p=0.056 for VCR, 0.005 for VMR and 0.022 for VOR, respectively). Both number of altered reflexes entity of compromission were significantly higher in patients than in controls (p=0.017 and 0.001, respectively). A consistent correlation with VEMPs alterations was found only for high scores on RBD-SQ (p=0.014). VEMPs showed low sensibility and high specificity and positive predictive value. VEMPs battery may arise as a new tool for detecting brainstem alterations in PD patients

Effect of Contralateral Strength Training on Muscle Weakness in People With Multiple Sclerosis: Proof-of-Concept Case Series

BackgroundThe contralateral strength training (CST) effect is a transfer of muscle performance to the untrained limb following training of the contralateral side.ObjectiveThe aim of this study was to explore, in individuals with multiple sclerosis (MS) presenting marked lower limb strength asymmetry, the effectiveness of CST on management of muscle weakness of the more-affected limb following training of the less-affected limb.DesignA single-subject research design was used.MethodsEight individuals with MS underwent 16 to 18 high-intensity training sessions of the less-affected ankle dorsiflexor muscles. The primary outcome measure of this single-system case series was maximal strength expressed as peak moment and maximal work. Secondary outcome measures were: Six-Minute-Walk Test, Timed "Up & Go" Test, 10-Meter Timed Walk Test, and Multiple Sclerosis Quality of Life–54 questionnaire.ResultsAfter the 6-week intervention, the contralateral more affected (untrained) limb showed a 22% to 24% increase in maximal strength. From pretest-posttest measurements, participants also performed significantly better on the clinical and functional secondary outcome measures. At the 12-week follow-up, the strength levels of the weaker untrained limb remained significantly superior to baseline levels in the majority (5 out of 8) of the outcome parameters.LimitationsConsidering the design used, the absence of a control group, and the sample size, these findings should be cautiously generalized and will need confirmation in a properly planned randomized controlled trial.ConclusionsThe present proof-of-concept study shows, for the first time, the occurrence of the CST effect on muscle performance of ankle dorsiflexor muscles in people with MS. These preliminary findings reveal new potential implications for CST as a promising rehabilitation approach to those conditions where unilateral muscle weakness does not allow or makes difficult performing conventional strength training of the weaker limb

Research Evidence of the Role of the Glymphatic System and Its Potential Pharmacological Modulation in Neurodegenerative Diseases

The glymphatic system is a unique pathway that utilises end-feet Aquaporin 4 (AQP4) channels within perivascular astrocytes, which is believed to cause cerebrospinal fluid (CSF) inflow into perivascular space (PVS), providing nutrients and waste disposal of the brain parenchyma. It is theorised that the bulk flow of CSF within the PVS removes waste products, soluble proteins, and products of metabolic activity, such as amyloid-β (Aβ). In the experimental model, the glymphatic system is selectively active during slow-wave sleep, and its activity is affected by both sleep dysfunction and deprivation. Dysfunction of the glymphatic system has been proposed as a potential key driver of neurodegeneration. This hypothesis is indirectly supported by the close relationship between neurodegenerative diseases and sleep alterations, frequently occurring years before the clinical diagnosis. Therefore, a detailed characterisation of the function of the glymphatic system in human physiology and disease would shed light on its early stage pathophysiology. The study of the glymphatic system is also critical to identifying means for its pharmacological modulation, which may have the potential for disease modification. This review will critically outline the primary evidence from literature about the dysfunction of the glymphatic system in neurodegeneration and discuss the rationale and current knowledge about pharmacological modulation of the glymphatic system in the animal model and its potential clinical applications in human clinical trials

A Comprehensive assessment of the cross-training effect in ankle dorsiflexors of healthy subjects: a randomized controlled study

Purpose: To investigate the cross-training effect, induced on ankle dorsiflexors (AD) by unilateral strength-training of the contralateral muscles, as transfer of peak torque (PT) and muscle work (MW) and their relative contributions to muscle performance. Methods: Thirty healthy volunteers were randomly assigned to a training or control group. The trained group sustained a 4-week maximal isokinetic training of the stronger AD at 90 and 45°/s. At both angular velocities, PT, MW and MW/PT ratio were measured from both legs at baseline and after intervention (trained group) or no-intervention (controls). The familiarization/learning-effect was calculated and subtracted by PT and MW measures to obtain their net changes. Results: Net PT increased in both legs (untrained: +27.5% at 90°/s and +17.9% at 45°/s; trained: +15% at 90°/s and +16.3% at 45°/s). Similarly, net MW increased in both the untrained (90°/s: +29.6%; 45°/s: +37%) and trained (90°/s: +23.4%; 45°/s: +18.3%) legs. PT and MW gains were larger in the untrained than trained AD (p < 0.0005), with MW improving more than PT at 45°/s (p = 0.04). The MW/PT ratio increased bilaterally only in the trained group (p < 0.05), depending on the angular velocity. Conclusions: The cross-training effect occurred in AD muscles in terms of both PT and MW, with MW adding valuable information to PT-analysis in describing muscle performance. Moreover, the MW/PT ratio allowed estimating the contributions of these parameters to muscle capability and may represent a novel index in isokinetic testing. The greater improvements in the untrained than trained limb raises interesting clinical implications in asymmetric conditions

Vestibular evoked myogenic potentials are abnormal in idiopathic REM sleep behavior disorder

Objectives: To investigate brainstem function in idiopathic REM sleep Behavior Disorder (iRBD), a condition occurring as a result of a derangement of connections within brainstem structures, with a battery of Vestibular Evoked Myogenic Potentials (VEMPs), neurophysiological tools suited for the functional investigation of the brainstem. Neurophysiological data were correlated with clinical characteristics of patients. Methods: Twenty patients with iRBD and 22 healthy controls underwent cervical (cVEMP), masseter (mVEMP) and ocular (oVEMP) VEMP recording. Patients were assessed clinically according to presence of motor as well as non-motor symptoms such as constipation, depression, and hyposmia. Also, they were screened for postural instability through the Berg Balance Scale (BBS). VEMPs were categorized as for increasing degrees of abnormalities, namely latency delay, amplitude reduction and absence; a VEMP score was built accordingly. Results: Compared with controls, iRBD had higher rates of abnormalities both in the VEMP battery (iRBD 75%, Controls 23%; p < 0.01) as well as in each single VEMP (cVEMP: 45 vs. 5%; mVEMP: 65 vs. 13.6%; oVEMP: 50 vs. 5%; p < 0.01), which exhibited significantly lower amplitudes (cVEMP and oVEMP: p < 0.0001; mVEMP: p = 0.001) in iRBD. Within altered reflexes, absence was predominant in oVEMP (81%), amplitude reduction in mVEMP (50%) and cVEMP (70%). Severity of VEMP alterations was significantly higher in iRBD compared with controls (p < 0.05 for all VEMPs), as indicated by the larger VEMP scores in the former. The oVEMP score correlated inversely with poor performances on the BBS. Conclusion: VEMPs unveil consistent and extensive brainstem abnormalities in iRBD patients. Further studies are warranted for testing the potential of VEMPs in the monitoring of the evolution of iRBD over time

Ultrasound and laser as stand-alone therapies for myofascial trigger points: a randomized, double-blind, placebo-controlled study

Background and Purpose. Ultrasound (US) and low-level laser therapy (LLLT) are commonly employed for myofascial trigger points (MTP) despite lack of evidence for usage as stand-alone treatments. The aim of the study was to determine, on MTP of the upper trapezius muscle (uTM), the effects of US and LLLT per se, as delivered in accordance with the procedures reported by surveys about their usage among physiotherapists. Methods. Design was set as a double-blind, randomized, placebo-controlled study. Sixty participants with at least one active MTP in uTM (28 women and 32 men; mean age 24.5 ± 1.44 years) were recruited and randomly assigned to one out of five groups: active US (n = 12), placebo US (n = 12), active LLLT (n = 11), placebo LLLT (n = 11) and no therapy (control, n = 14). The participants and outcome assessor were blinded to the group assignment and therapy delivered. Three outcome measures were assessed at baseline, after a 2-week treatment and 12 weeks after the end of the intervention (follow-up): pressure pain threshold, subjective pain on a numerical rating scale and muscle extensibility performing a cervical lateral flexion. All subjects assigned to the intervention groups were treated five times weekly for overall 10 treatments given. Two-way ANOVA was used to compare differences before and after intervention and among groups at each time-point. Results. After the 2-week intervention, all groups showed pressure pain threshold, numerical rating scale and cervical lateral flexion significant improvements (p&lt;0.05), which were confirmed at the follow-up. When performing multiple comparisons, controls scored significantly less than both the active therapies and placebos, whereas no differences were detected between active therapies and placebos. Conclusions. Ultrasound and LLLT provided significant improvements in pain and muscle extensibility, which were superior to no therapy but not to placebos, thus raising concerns about the suitability, both economically and ethically, of administering such common physical modalities as stand-alone treatments in active MTP of the uTM.</br

Abnormalities of vestibular-evoked myogenic potentials in idiopathic Parkinson’s disease are associated with clinical evidence of brainstem involvement

Brainstem degeneration in Parkinson’s disease (PD) may explain the occurrence of many non-motor symptoms in this condition. Purposes of the present work were to investigate brainstem function in PD through a battery of vestibular-evoked myogenic potentials (VEMP) allowing a comprehensive brainstem exploration and to correlate VEMP findings with symptoms related to brainstem involvement. Cervical (cVEMP), masseter (mVEMP) and ocular (oVEMP) VEMPs were investigated in 24 PD patients and compared with those recorded in 24 age-matched controls. Presence of symptoms ascribable to brainstem dysfunction, such as daytime sleepiness, REM sleep behavior disorder and depression, was investigated through Epworth Sleepiness Scale, Parkinson’s Disease Sleep Scale, REM Sleep Disorder Screening Questionnaire (RBD-SQ) and Geriatric Depression Scale. Postural instability was additionally assessed through mini-BESTest. The frequency of alteration of VEMPs in patients was 83.3 % when considering the whole set and 41.7 % for cVEMP, 66.7 % for mVEMP and 45.8 % for oVEMP. This was significantly different from controls, with absence being the prevalent alteration in PD. A significant inverse correlation between the number of altered VEMPs and mini-BESTest and a direct correlation with RBD-SQ were found. The VEMP battery under study allowed the identification of brainstem dysfunctions in PD patients, which correlated with clinical tests suggestive of postural and REM sleep disorders. VEMPs might represent a valuable tool of brainstem assessment in PD

Paired neurophysiological and clinical study of the brainstem at different stages of Parkinson’s disease

Objective To study brainstem function in Parkinson’s Disease (PD) at different stages, through a battery of vestibular-evoked myogenic potentials (VEMPs) and compare the results with scores on clinical scales assessing the presence of symptoms linked to brainstem involvement. Methods Cervical, masseter and ocular VEMPs were recorded in patients with early PD (n = 14, disease duration 1.42 ± 0.7 years), advanced PD (n = 19, disease duration 7.26 ± 2.9 years) and in 27 age-matched controls. In PD, the following clinical scales were administered: Mini-BESTest, REM sleep Behavior Disorder Screening Questionnaire (RBD-SQ), PD Sleep Scale, Epworth Sleepiness Scale and Geriatric Depression Scale. Results Rate of VEMPs alterations was higher (p &lt; 0.001) in PD than controls, but similar within PD groups. However, early and advanced PD showed a different pattern of abnormalities (p = 0.02), being latency delay prevalent in the former and absence in the latter. VEMP impairment correlated directly with RBD-SQ scores in both PD cohorts and inversely with Mini-BESTest scores in advanced PD. Conclusions VEMPs displayed progressive severity of alterations at different stages of PD, with remarkable correlations with presence of postural instability and RBD. Significance The combined use of VEMPs may provide interesting insights into the pathophysiological mechanisms of PD at the earliest and prodromal stage of the disease