Slowing of EEG waves correlates with striatal [18 F]fluorodopa PET/CT uptake and executive dysfunction in Parkinson's disease.

Parkinson's disease (PD) research on specific neuroimaging and neurophysiological biomarkers revealing executive dysfunction mechanisms is limited, necessitating validation. Thus, our study aimed to assess associations between electroencephalographic power spectral density (PSD-EEG), striatal [18 F]Fluorodopa uptake and neuropsychological executive function (EF) testing parameters in PD, while also estimating their diagnostic accuracy. We compared resting PSD-EEG, striatal [18 F]Fluorodopa uptake ratios based on positron emission computed tomography ([18 F]FDOPA PET/CT) and neuropsychological EF tests outcomes [Trail Making Test (TMT) and Stroop Test (ST)] between PD patients and healthy controls (HCO) and then calculated correlations among these measures separately for each group. Additionally, we estimated PD diagnostic accuracy of the PSD-EEG and [18 F]FDOPA PET/CT parameters. In PD patients, we observed the following: (i) slower EEG waves, reflected in increased power of the EEG theta and lower-alpha bands in frontal lobe areas; (ii) reduced [18 F]FDOPA PET/CT uptake in the putaminal and caudate nuclei, along with a decreased putamen-to-caudate ratio ([18 F]FDOPA PET/CT PCR); and (iii) longer performance times evident in nearly all EF tests' parameters. Slower EEG waves correlated negatively with [18 F]FDOPA PET/CT PCR and positively with most of the EF test parameters. Furthermore, we found negative correlations between [18 F]FDOPA PET/CT PCR and certain EF measures related to ST. [18 F]FDOPA PET/CT ratios and several PSD-EEG parameters, particularly those from the prefrontal cortex, demonstrated clinically reasonable diagnostic accuracy for PD. In conclusion, EEG waves slowing in the frontal lobe were correlated with striatal dopaminergic deficiency and impaired executive function in mild PD patients and showed promise as a biomarker of PD-related executive dysfunction.

Myofascial Trigger Points therapy decreases myotonometric tone and stiffness of trapezius muscle, benefits headaches and muscle pain in migraine.

BACKGROUND: Migraine is a primary headache disorder. Studies have shown that 93% of people with migraine have an increased number of active Ischemic Compression Myofascial Trigger Points (IC-MTrPs) therapy. OBJECTIVE: To examine the effects of the IC-MTrPs therapy on: (1) mechanical properties of the upper trapezius muscle (UTM), (2) shoulder girdle and neck (SGN) muscles pain and (3) headaches characteristics in episodic migraine patients without aura. METHODS: Thirty-one adult, female, migraine patients without aura underwent seven IC-MTrPs therapy sessions and were tested during maximally five measurement sessions (pre- and post-1'st, post-4'th, post-7'th therapy and 1-month follow-up). Myotonometric measurements of the UTM's tone, stiffness and elasticity, subjective SGN muscles pain, as well as headache's level, frequency and duration were analyzed. RESULTS: Myotonometric tone and stiffness of the UTM significantly decreased in post-1'st, post-4'th therapy and in 1-month follow-up measurements versus pre-1'st therapy testing session. The scores for the SGN muscles' pain significantly decreased: (i) in post-4'th and post-7'th therapy versus post-1'st therapy session, and (ii) in post-7'th versus post-4'th therapy measurements. Headache's level, frequency and duration significantly decreased in post-7'th therapy versus pre-1'st therapy measurement session. CONCLUSION: IC-MTrPs therapy resulted in a decrease of upper trapezius muscle tone and stiffness, with simultaneous alleviation of shoulder girdle and neck muscle pain and the headaches characteristics in episodic migraine patients without aura.

Motor imagery training of goal-directed reaching in relation to imagery of reaching and grasping in healthy people.

The study aimed to determine whether four weeks of motor imagery training (MIT) of goal-directed reaching (reaching to grasp task) would affect the cortical activity during motor imagery of reaching (MIR) and grasping (MIG) in the same way. We examined cortical activity regarding event-related potentials (ERPs) in healthy young participants. Our study also evaluated the subjective vividness of the imagery. Furthermore, we aimed to determine the relationship between the subjective assessment of motor imagery (MI) ability to reach and grasp and the cortical activity during those tasks before and after training to understand the underlying neuroplasticity mechanisms. Twenty-seven volunteers participated in MIT of goal-directed reaching and two measurement sessions before and after MIT. During the sessions 128-channel electroencephalography (EEG) was recorded during MIR and MIG. Also, participants assessed the vividness of the MI tasks using a visual analog scale (VAS). The vividness of imagination improved significantly (P < .05) after MIT. A repeated measures ANOVA showed that the task (MIR/MIG) and the location of electrodes had a significant effect on the ERP's amplitude (P < .05). The interaction between the task, location, and session (before/after MIT) also had a significant effect on the ERP's amplitude (P < .05). Finally, the location of electrodes and the interaction between location and session had a significant effect on the ERP's latency (P < .05). We found that MIT influenced the EEG signal associated with reaching differently than grasping. The effect was more pronounced for MIR than for MIG. Correlation analysis showed that changes in the assessed parameters due to MIT reduced the relationship between the subjective evaluation of imagining and the EEG signal. This finding means that the subjective evaluation of imagining cannot be a simple, functional insight into the bioelectrical activity of the cerebral cortex expressed by the ERPs in mental training. The changes we noted in ERPs after MIT may benefit the use of non-invasive EEG in the brain-computer interface (BCI) context.Trial registration: NCT04048083.

Heightened tone and stiffness with concurrent lowered elasticity of peroneus longus and tibialis anterior muscles in athletes with chronic ankle instability as measured by myotonometry.

In a recent study, myotonometry revealed adverse alterations in the mechanical properties of ankle periarticular muscles in soldiers reporting previous lateral ankle sprain (LAS) incidents. This knowledge, if confirmed in athletes with developed chronic ankle instability (CAI), may have important diagnostic and therapeutic implications in sports medicine and rehabilitation. Consequently, the purpose of the study was to explore mechanical properties of the peroneus longus (PL), tibialis anterior (TA), and the lateral and medial gastrocnemius (LG and MG, respectively) muscles in athletes suffering CAI. Fourteen adult male athletes with developed CAI (International Ankle Consortium selection criteria) and 15 healthy male athletes without any LAS incidence as the control group (CO) participated in the study. The CAI and CO groups were characterized by similar anthropometric parameters and weekly training volume. In both the groups of athletes, we performed resting state (controlled with electromyographic recordings) myotonometric measurements (using a MyotonPRO® device) in the PL, TA, LG and MG muscles and calculated the following five myotonometric parameters: frequency (F-MYO), stiffness (S-MYO), decrement (d-MYO), relaxation time (R-MYO) and creep (C-MYO). Athletes from the CAI group (compared to the CO group) exhibited significantly higher values of F-MYO and S-MYO as well as lower values of R-MYO and C-MYO in the PL and TA muscles. No significant inter-group differences were found in the remaining myotonometric parameters. Using myotonometry, our study is the first to reveal that athletes with developed CAI are characterized by heightened tone and stiffness with concurrent lowered elasticity of the PL and TA muscles.

High-intensity interval training modulates inflammatory response in Parkinson's disease.

BACKGROUND: Recent discoveries show that high-intensity interval training (HIIT) can bring many positive effects such as decreases in fat tissue, lower blood sugar levels, improved learning and memory, and lower risk of cardiac disease. Parkinson's disease (PD) is a neurodegenerative disorder characterized by loss of the dopaminergic neurons, accompanied by chronic inflammation and neuroinflammation. Previous research shows that interval training can bring a beneficial effect on the inflammation and neuroplasticity in PD. OBJECTIVES: The objective of this study was to investigate the effect of 12 weeks of HIIT on the inflammation levels and antioxidant capacity in the serum of PD patients. METHODS: Twenty-eight people diagnosed with PD were enrolled in this study. Fifteen PD patients performed 12 weeks of HIIT on a cycloergometer. Thirteen non-exercised PD patients constitute the control group. Concentrations of inflammation markers and antioxidants' capacity in the serum were measured at 3 sampling points (a week before, a week after, and 3 months after the HIIT). RESULTS: Twelve weeks of HIIT decreases the level of TNF-α (p = 0.034) and increases the level of IL-10 (p = 0.024). Those changes were accompanied by a decreased level of neutrophils (p = 0.03), neutrophil/lymphocyte ratio (p = 0.048) and neutrophil/monocyte ratio (p = 0.0049) with increases in superoxide dismutase levels (p = 0.04). CONCLUSIONS: Twelve weeks of HIIT can decrease systemic inflammation in PD patients and improve the antioxidant capacity in their serum, which can slow down the progression of the disease.

Neuroplasticity in Motor Learning Under Variable and Constant Practice Conditions-Protocol of Randomized Controlled Trial.

Background: There is numerous literature on mechanisms underlying variability of practice advantages. Literature includes both behavioral and neuroimaging studies. Unfortunately, no studies are focusing on practice in constant conditions to the best of our knowledge. Hence it is essential to assess possible differences in mechanisms of neuroplasticity between constant vs. variable practice conditions. The primary objectives of the study described in this protocol will be: (1) to determine the brain's structural and functional changes following constant and variable practice conditions in motor learning (structural and functional magnetic resonance imaging, MRI); (2) to determine the EEG activation and connectivity between cognitive, sensory, and motor cerebral cortex areas (central, temporal, parietal, occipital) in constant and variable practice conditions and as a function of practice time. Methods: The study will follow the interventional (experimental) design with two arms (parallel groups). Fifty participants will be randomly assigned to two groups practicing in constant (CG) and variable conditions (VG). CG will be practicing only one pattern of step isometric contractions during unimanual index finger abduction, i.e., 90 trials in all training sessions, whereas VG will practice three different patterns. Each will be practiced 30 times per session in variable conditions. Resting-state fMRI, EEG (cortical networking), and motor task proficiency will be examined before (pre-) and after practice (post- and retentions tests). Discussion: Findings will enhance our understanding of structural and functional neural changes following practice in constant and variable conditions. Therefore, the study can be considered pure (basic) research (clinical research in healthy individuals). Clinical Trial Registration: Study registered at clinicaltrials.gov (ID# NCT04921072) on 9 June 2021. Last version update: 21 December 2021.The protocol has been prepared according to the complete SPIRIT checklist (http://www.spirit-statement.org/), although the item order has been modified in order to comply with the manuscript structure.

Effect of gender, muscle type and skinfold thickness on myometric parameters in young people.

BACKGROUND: The aim of the study was to compare the mechanical properties of three human skeletal muscles: biceps brachii (BB), rectus femoris (RF), and tibialis anterior (TA) at rest measured by myoton device in males (n = 16, mean age 21.2 ± 0.6 years) and females (n = 16; 21.2 ± 0.9 years) and to investigate the influence of skin and subcutaneous tissue thickness (skinfold thickness, SFT) and gender on myometric parameters of the three skeletal muscles. METHODS: We measured the following mechanical and viscoelastic muscle properties using MyotonPRO®: frequency (F [Hz]), decrement (D [log]), stiffness (S [N/m]), relaxation time (R [ms]) and creepability (C [De]). The values of SFT for all selected muscles were assessed by caliper. A mixed-design analysis of variance with gender as between subject comparison was used for assessing the differences between gender and muscles in SFT and each of the myometric parameters separately (F, D, S, R and C). Pearson correlation coefficient or Spearman's rank correlation coefficient between SFT and myometric parameters was conducted for males, females and males and females together. The level of statistical significance was set at α ≤ 0.05 with Bonferroni correction for multiple comparisons. RESULTS: The SFT over the RF, TA, and BB muscles in women was statistically significantly larger compared with that of males. In females and males, the SFT over the RF was larger than over the TA and BB, and the SFT over the TA was larger compared with over the BB. The values of F and S recorded for the TA muscle were the highest among the three muscles, while D, C, and R were lowest in TA but highest in the RF muscle in men and women. The values of F and S were smaller in females than in males. Gender comparison of D, C, and R values showed that only D for the RF was significantly lower in females than in males, and C for the RF and TA was significantly larger in females than in males. Some correlation between SFT and myometric parameters were different between males and females. For example, there was a significant, negative correlation between SFT and F for all muscles in females, and a significant, positive correlation between these parameters for BB and TA (not for RF) in males. For pooled data (males and females together), a negative significant correlation between SFT and F was observed for RF and TA (not significant for BB muscle). DISCUSSION: It is concluded that the TA compared with the BB and RF has significantly greater F and S but the smallest D and C and the shortest R. Gender and muscle differences in the SFT may affect the measurements of muscle properties using MyotonPRO®. The relationship between SFT and myometric parameters is different in males and females in the RF, TA, and BB muscles. Therefore, the myometric data should be analyzed in males and females separately.

Motor Imagery Training of Reaching-to-Grasp Movement Supplemented by a Virtual Environment in an Individual With Congenital Bilateral Transverse Upper-Limb Deficiency.

This study explored the effect of kinesthetic motor imagery training on reaching-to-grasp movement supplemented by a virtual environment in a patient with congenital bilateral transverse upper-limb deficiency. Based on a theoretical assumption, it is possible to conduct such training in this patient. The aim of this study was to evaluate whether cortical activity related to motor imagery of reaching and motor imagery of grasping of the right upper limb was changed by computer-aided imagery training (CAIT) in a patient who was born without upper limbs compared to a healthy control subject, as characterized by multi-channel electroencephalography (EEG) signals recorded before and 4, 8, and 12 weeks after CAIT. The main task during CAIT was to kinesthetically imagine the execution of reaching-to-grasp movements without any muscle activation, supplemented by computer visualization of movements provided by a special headset. Our experiment showed that CAIT can be conducted in the patient with higher vividness of imagery for reaching than grasping tasks. Our results confirm that CAIT can change brain activation patterns in areas related to motor planning and the execution of reaching and grasping movements, and that the effect was more pronounced in the patient than in the healthy control subject. The results show that CAIT has a different effect on the cortical activity related to the motor imagery of a reaching task than on the cortical activity related to the motor imagery of a grasping task. The change observed in the activation patterns could indicate CAIT-induced neuroplasticity, which could potentially be useful in rehabilitation or brain-computer interface purposes for such patients, especially before and after transplantation. This study was part of a registered experiment (ID: NCT04048083).

High-density surface electromyography maps after computer-aided training in individual with congenital transverse deficiency: a case study.

BACKGROUND: The aim of this study was to determine whether computer-aided training (CAT) of motor tasks would increase muscle activity and change its spatial distribution in a patient with a bilateral upper-limb congenital transverse deficiency. We believe that our study makes a significant contribution to the literature because it demonstrates the usefulness of CAT in promoting the neuromuscular adaptation in people with congenital limb deficiencies and altered body image. CASE PRESENTATION: The patient with bilateral upper-limb congenital transverse deficiency and the healthy control subject performed 12 weeks of the CAT. The subject's task was to imagine reaching and grasping a book with the hand. Subjects were provided a visual animation of that movement and sensory feedback to facilitate the mental engagement to accomplish the task. High-density electromyography (HD-EMG; 64-electrode) were collected from the trapezius muscle during a shrug isometric contraction before and after 4, 8, 12 weeks of the training. After training, we observed in our patient changes in the spatial distribution of the activation, and the increased average intensity of the EMG maps and maximal force. CONCLUSIONS: These results, although from only one patient, suggest that mental training supported by computer-generated visual and sensory stimuli leads to beneficial changes in muscle strength and activity. The increased muscle activation and changed spatial distribution of the EMG activity after mental training may indicate the training-induced functional plasticity of the motor activation strategy within the trapezius muscle in individual with bilateral upper-limb congenital transverse deficiency. Marked changes in spatial distribution during the submaximal contraction in the patient after training could be associated with changes of the neural drive to the muscle, which corresponds with specific (unfamiliar for patient) motor task. These findings are relevant to neuromuscular functional rehabilitation in patients with a bilateral upper-limb congenital transverse deficiency especially before and after upper limb transplantation and to development of the EMG based prostheses.

Eight Weeks of Aerobic Interval Training Improves Psychomotor Function in Patients with Parkinson's Disease-Randomized Controlled Trial.

BACKGROUND: This study examined the generalized effects of cycle ergometer aerobic interval training (AIT) on psychomotor behaviors in individuals with Parkinson's disease (PD), including bimanual motor control, cognitive function, and neurological motor and non-motor parkinsonian signs. METHODS: Twenty mild to moderate PD patients were randomly allocated to the following groups: (1) trained group (PD-TR, n = 10), which besides receiving usual care, underwent an 8-week moderate intensity AIT program; or (2) control group (PD-CO, n = 10) which received usual care, including participation in conventional physical therapy. Both groups were tested before and after the 8-week AIT program period with the following assessments: (1) laboratory analyses of bimanual motor control, (2) psychological evaluation of cognitive function, and (3) an evaluation of neurological parkinsonian signs. RESULTS: The PD-TR group exhibited improved (1) bimanual motor control, reflected by a decreased time (p = 0.013) and increased rate of grip force development (p = 0.013) in the manipulating hand and a decreased time delay between grip force initiation in the manipulating and stabilizing hand (p = 0.020); (2) executive function, reflected by decreased performance time in part II of the Stroop Test (p = 0.007); and (3) neurological parkinsonian signs, reflected by an amelioration of upper-extremity bradykinesia (p = 0.015) and improvement in daily life manual functions (p = 0.004), mood, and intellectual function (p = 0.005). CONCLUSIONS: Following an 8-week moderate intensity AIT program, patients with PD exhibited improved psychomotor behaviors, reflected by bimanual motor control, executive function, and neurological parkinsonian signs.

Influence of number of records on reliability of myotonometric measurements of muscle stiffness at rest and contraction.

PURPOSE: The aim of this study was to determine an effect of myotonometric records' number on stiffness measurements' reliability in muscles at rest and contraction. METHODS: Muscle stiffness was measured using Myoton-3 device. Twenty records were taken for: (i) biceps (BB) and triceps brachii (TB) at rest and for BB at 10% of maximal voluntary contraction (MVC) in healthy elderlies (HE) and in Parkinson's disease patients (PD); and (ii) brachioradialis (BR) at rest and at 25, 50 and 80% MVC in healthy young (HY) subjects. Also, in HY group, the 3-records mode was used for BR's measurements at maximal contraction. Each measurement taken with 20-records was classed into five records groups: the whole 20- and the first 15-, 10-, 5- and 3-records. Test-retest reliability for these records groups was analyzed. RESULTS: In HE and PD group measurements' reliability was excellent for all groups of records (20-3 rec- ords). In HY group, for the five groups of records taken at rest and submaximal levels of contraction (25, 50 and 80% MVC) the meas- urements reliability: (i) was mostly excellent or rarely average; and (ii) only in one per three 50% MVC conditions was unacceptable, i.e., for the 3-records group. The reliability of 3-records mode measurements at maximal contraction were unacceptable. CONCLUSIONS: Reliable myotonometric stiffness measurements in muscles at rest and during submaximal contractions can be achieved with less than 20 records (15, 10, 5 records) and even for the most of measurements with 3 records in HY and HE as well as in the PD patients. Myotonometric stiffness measurements with 3-records mode during maximal contraction were not reliable.

Influence of dopaminergic treatment on resting elbow joint angle control mechanisms in patients with Parkinson's disease - a preliminary report.

PURPOSE: Heightened tonic stretch reflex contributes to increased muscle tone and a more-flexed resting elbow joint angle (EJA) in patients with Parkinson's disease (PD). Dopaminergic medication restores central nervous system (CNS) functioning and decreases resting muscle electrical and mechanical activities. This study aimed to evaluate the effects of dopaminergic medication on parkinsonian rigidity, resting EJA, resting electrical activity (electromyography, EMG) and mechanical properties (myotonometry, MYO) of elbow flexor muscles and the associations of EJA with these muscles resting electrical activity and mechanical properties in PD patients. We also evaluated a relationship between dopaminergic treatment dose and these outcome measures values. METHODS: Ten PD patients (age 68 ± 10.1 years; body mass 70 ± 16.8 kg; height 162 ± 6.6 cm; illness duration 9 ± 4.5 years) were tested during medication on- and off-phases. Resting EJA, myotonometric muscle stiffness (S-MYO) and root mean square electromyogram amplitude (RMS-EMG) were recorded from relaxed biceps brachii and brachioradialis muscles. Based on the above parameters, we also calculated the EJA/S-MYO ratio and EJA/RMS-EMG ratio. Parkinsonian rigidity was assessed using the motor section of the Unified Parkinson's Disease Rating Scale. RESULTS: EJA, EJA/S-MYO ratio, and EJA/RMS-EMG ratio were increased and S-MYO, RMS-EMG, and parkinsonian rigidity were decreased during the medication on-phase compared with the off-phase. In addition, the dopaminergic treatment dose was negatively correlated with S-MYO and RMS-EMG, and positively correlated with EJA/SMYO and EJA/RMS-EMG ratios. CONCLUSIONS: We conclude that dopaminergic medication- induced improvements in resting elbow joint angle in tested patients with PD are related to changes in their muscle electrical and mechanical properties.

Computer-aided training sensorimotor cortex functions in humans before the upper limb transplantation using virtual reality and sensory feedback.

One of the biggest problems of upper limb transplantation is lack of certainty as to whether a patient will be able to control voluntary movements of transplanted hands. Based on findings of the recent research on brain cortex plasticity, a premise can be drawn that mental training supported with visual and sensory feedback can cause structural and functional reorganization of the sensorimotor cortex, which leads to recovery of function associated with the control of movements performed by the upper limbs. In this study, authors - based on the above observations - propose the computer-aided training (CAT) system, which generating visual and sensory stimuli, should enhance the effectiveness of mental training applied to humans before upper limb transplantation. The basis for the concept of computer-aided training system is a virtual hand whose reaching and grasping movements the trained patient can observe on the VR headset screen (visual feedback) and whose contact with virtual objects the patient can feel as a touch (sensory feedback). The computer training system is composed of three main components: (1) the system generating 3D virtual world in which the patient sees the virtual limb from the perspective as if it were his/her own hand; (2) sensory feedback transforming information about the interaction of the virtual hand with the grasped object into mechanical vibration; (3) the therapist's panel for controlling the training course. Results of the case study demonstrate that mental training supported with visual and sensory stimuli generated by the computer system leads to a beneficial change of the brain activity related to motor control of the reaching in the patient with bilateral upper limb congenital transverse deficiency.

Low-Frequency Fatigue Assessed as Double to Single Twitch Ratio after Two Bouts of Eccentric Exercise of the Elbow Flexors.

The aim of this study was to assess low-frequency fatigue as a double to single twitch ratio after repeated eccentric exercise of the elbow flexors. Maximal isometric torque, single and double twitch responses and low-frequency fatigue were assessed on the elbow flexors in 16 untrained male volunteers before, immediately after, 24 and 48 hours following two bouts of eccentric exercise consisted of 30 repetitions of lowering a dumbbell adjusted to ~75% of each individual's maximal isometric torque. Maximal isometric torque and electrically evoked responses decreased significantly in all measurements after the first bout of eccentric exercise (p < 0.05). In measurements performed at 24 and 48 hours after the second bout both maximal voluntary isometric torque and electrically evoked contractions were significantly higher than in measurements performed after the first bout (p < 0.05). Although low-frequency fatigue significantly increased up to 48 hours after each bout of eccentric exercise, its values at 24 and 48 hours after the second bout were significantly lower than at respective time points after the first bout (p < 0.05). Double to single twitch ratio could be used as a sensitive tool in the evaluation of muscle recovery and adaptation to repeated eccentric exercise.

Spike shape analysis of electromyography for parkinsonian tremor evaluation.

INTRODUCTION: Standard electromyography (EMG) parameters have limited utility for evaluation of Parkinson disease (PD) tremor. Spike shape analysis (SSA) EMG parameters are more sensitive than standard EMG parameters for studying motor control mechanisms in healthy subjects. SSA of EMG has not been used to assess parkinsonian tremor. This study assessed the utility of SSA and standard time and frequency analysis for electromyographic evaluation of PD-related resting tremor. METHODS: We analyzed 1-s periods of EMG recordings to detect nontremor and tremor signals in relaxed biceps brachii muscle of seven mild to moderate PD patients. RESULTS: SSA revealed higher mean spike amplitude, duration, and slope and lower mean spike frequency in tremor signals than in nontremor signals. Standard EMG parameters (root mean square, median, and mean frequency) did not show differences between the tremor and nontremor signals. CONCLUSIONS: SSA of EMG data is a sensitive method for parkinsonian tremor evaluation.

Interval training-induced alleviation of rigidity and hypertonia in patients with Parkinson's disease is accompanied by increased basal serum brain-derived neurotrophic factor.

OBJECTIVE: To examine the effects of cycloergometric interval training on parkinsonian rigidity, relaxed biceps brachii muscle tone in affected upper extremities, and serum level of brain-derived neurotrophic factor. DESIGN: Case series, repeated-measures design, pilot study. SUBJECTS/PATIENTS: Eleven patients with mild-to-moderate Parkinson's disease (Hoehn & Yahr scale 2.3 ± 0.72), recruited from a neurological clinic, underwent cycle training and were tested along with non-trained, healthy control subjects (n = 11) in a motor control laboratory. METHODS: Patients underwent 8 weeks of interval training (3 × 1-h sessions weekly, consisting of a 10-min warm-up, 40 min of interval exercise, and 10-min cool-down) on a stationary cycloergometer. Parkinsonian rigidity (Unified Parkinson's Disease-Rating-Scale) in the upper extremity, resting biceps brachii muscle tone (myometric stiffness and frequency), and brain-derived neurotrophic factor level were measured 1-3 days before interval training cycle started and 6-10 days after the last training session. RESULTS: Training resulted in a decrease in rigidity (p = 0.048) and biceps brachii myometric muscle stiffness (p = 0.030) and frequency (p = 0.006), and an increase in the level of brain-derived neurotrophic factor (p = 0.035) relative to pre-training values. The increase in brain-derived neurotrophic factor level correlated with improvements in parkinsonian rigidity (p = 0.025), biceps brachii myometric stiffness (p = 0.001) and frequency (p = 0.002). CONCLUSION: Training-induced alleviation of parkinsonian rigidity and muscle tone decrease may be associated with neuroplastic changes caused by a training-induced increase in the level of brain-derived neurotrophic factor.

Effects of submaximal eccentric exercise on muscle activity at different elbow joint angles.

Our study aimed to determine whether electrical and mechanical factors contributing to acute or long-term maximal torque reduction and muscle soreness due to submaximal eccentric exercise (ECC) are elbow-joint-angle specific and to what extent the joint angle affects the contribution of antagonist coactivation to this torque reduction. Maximal isometric torque (MIT), muscle soreness assessment, agonist electromechanical activities, and antagonist coactivation during the maximal voluntary contraction (MVC) were measured at elbow joint angles of 60°, 90°, and 150° before ECC, immediately after exercise, and 24, 48, 72, and 120 hr after exercise. ECC causes an immediate decrease in MIT as well as increased antagonist coactivation at three angles. Antagonist coactivation returned to its baseline level at 24 hr regardless of joint angle. The most rapid torque recovery and the highest force level at which pain occurred were found after ECC at a joint angle of 60°. During the recovery period, no mechanomyographical changes were observed when measuring surface mechanomyography changes at three angles, while the electrical activity differed between angles.

Twitch mechanical properties after repeated eccentric exercise of the elbow flexors.

The purpose of this study was to assess if the protective adaptation after eccentric exercise affects changes of twitch contractile properties of the biceps brachii muscle. Maximal isometric torque (MVC), twitch contractile properties, muscle soreness, and relaxed elbow angle (RANG) assessments were measured in 12 untrained, right-handed male volunteers (age, 23 ± 2 years; height, 182 ± 5 cm; mass, 75 ± 7 kg) before, immediately after, 48 h, and 120 h following each bout of eccentric exercise that consisted of 30 repetitions of lowering a dumbbell adjusted to 75% of each individual's maximal isometric torque of the right elbow flexors. MVC, peak twitch torque, maximal rate of twitch torque development, maximal rate of relaxation, muscle soreness, and RANG changes were significantly attenuated after the second bout of eccentric exercise when compared with the first bout. In contrast, time to twitch peak torque and half relaxation time did not change significantly after both the first and the second bout. The findings indicate that the mechanisms responsible for rapid adaptation affect some twitch mechanical properties such as peak torque, maximal rate of torque development, and maximal rate of relaxation but not time to peak torque and half relaxation time.

Myometry revealed medication-induced decrease in resting skeletal muscle stiffness in Parkinson's disease patients.

BACKGROUND: Based on combined analysis of clinical assessment of parkinsonian rigidity (constant resistance force generated during passive movement in a joint), electromyography and/or dynamometry many studies showed objectively that anti-parkinsonian medication decreases the rigidity in Parkinson's disease (PD). Rigidity-related changes in resting muscle stiffness (changed muscle's mechanical property related to its structural changes and changed neural drive) in PD patients have been revealed by myometry, a simple, sensitive, and reliable method for measuring mechanical properties in human soft tissues. However, an application of myometry in estimation of medication effects on the PD rigidity-related muscle stiffness has not been reported yet. Therefore, our study aimed to assess medication-induced changes in resting muscle stiffness in PD patients using myometry. METHODS: We measured resting muscle stiffness by myometry and recorded a surface electromyogram of relaxed biceps brachii, brachioradialis and triceps brachii muscles in ten patients with PD (age: 51-80 years; Hoehn and Yahr stage: 2.5-4) during medication on-phase (when subjects felt best comfort and fitness after medication: Levodopa, Piribedil, Ropinirol) and medication off-phase (12h after withdrawal of the medication). FINDINGS: Our patients had significantly lower myometric stiffness and electromyogram amplitude in all tested muscles, and also lower clinical rigidity scores during the medication on-phase compared with the medication off-phase. INTERPRETATION: Myometry revealed that anti-parkinsonian medication decreases not only rigidity in PD, but also rigidity-related stiffness in resting skeletal muscles in PD patients. These findings show that myometry can enrich neurological practice, by allowing objective and reliable assessment of parkinsonian rigidity treatment effectiveness.