Unilateral Movements Research Articles

Hemichorea-hemiballismus as the presenting manifestation of nonketotic hyperglycemia in an adolescent with undiagnosed type 2 diabetes mellitus

Hemichorea-hemiballismus as the presenting manifestation of nonketotic hyperglycemia in an adolescent with undiagnosed type 2 diabetes mellitus

Rare Presentation of Unilateral Weakness, Involuntary Movements and Ataxia with Subcortical T2 Hypointensity in a Diabetic Patient: A Case Report

Subcortical T2 hypointensity on MRI is not a common finding. We present a case of subcortical T2 hypointensity in a diabetic patient, who was referred with weakness of left lower limb and involuntary movements and ataxia of the left upper limb. Lab reports confirmed the diagnosis of nonketotic hyperglycemia. It is rather important to identify subcortical T2 hypointensity which has only been recently found to be associated with nonketotic hyperglycemia. Early identification and prompt correction of blood sugar would help in alleviating the neurological symptoms.

Effects of anticipation certainty on preparatory brain activity and anticipatory postural adjustments associated with voluntary unilateral arm movement while standing

We examined the effects of anticipation certainty concerning which voluntary movement is required in response to a stimulus while standing on preparatory brain activity and anticipatory postural adjustments (APAs). Ten right-handed adults abducted their left or right arm rapidly in response to a visual imperative stimulus, based on the type of stimulus. A warning cue, which did or did not contain information about the side of arm abduction, was presented 2000ms before the imperative stimulus. Preparatory brain activity before arm abduction was quantified by the mean amplitude of the contingent negative variation 100ms before the imperative stimulus (late CNV amplitude). Compared with the low anticipation condition, in the high anticipation condition the following results were obtained only in the case of right arm abduction: (1) larger late CNV amplitude, (2) earlier postural muscle activities with respect to the focal muscle of arm abduction, and (3) smaller peak displacement of center of pressure during the abduction. These findings suggest that high anticipation of voluntary movement of dominant arm to a stimulus while standing influences preparatory brain activity before the movement, resulting in earlier APAs and thus smaller disturbance of postural equilibrium during the movement.

Network Dynamics Mediating Ipsilateral Motor Cortex Activity during Unimanual Actions

Executing difficult actions with the left hand results in bilateral activity of motor areas along the precentral gyrus. Using TMS and fMRI, we explored the functional relationship between primary (M1) and premotor areas during unimanual actions, focusing on M1 activity in the ipsilateral hemisphere. Single-pulse TMS revealed that the amplitude of motor-evoked potentials (MEPs), elicited in the stationary right-hand muscles following left M1 stimulation, fluctuated with the state of homologous muscles in the moving left hand. This ipsilateral excitability was pronounced when the left-hand movements were more complex. We used fMRI to visualize the cortical dynamics during unimanual actions. Trial-by-trial fluctuations in ipsilateral M1 activity were correlated with contralateral M1 responses and this correlation increased with movement complexity. Consistent with previous studies, the left caudal precentral premotor area (pcPM) was engaged during movements of either hand. Following low-frequency rTMS over left pcPM, the correlation between the activity level in the two M1s increased. This finding indicates that left pcPM may regulate the unintentional mirroring of motor commands in M1 during unilateral movement.

Similarity in the dynamics of contralateral motor overflow through increasing frequency of movement in a single limb

This study was designed to investigate the effects of increasing movement frequency of a single limb on the degree of similarity and coherence of the motor outflow in the non-active limb. Twelve young adults performed a series of unilateral hand-clapping tasks (horizontal and vertical in 25-s trials) while seated. Individuals began the movements at a frequency of 1Hz for 5s and were required to increase the movement frequency so as to reach their maximum movement frequency during the latter parts of the trial. Hand and finger kinematics and surface EMG of each arm were recorded. The results showed a progressive emergence of overflow muscle activity and involuntary motion in the non-active arm as the movement frequency of the unilateral action increased toward the upper frequency limits of voluntary movement. This ceiling occurred within the range of 6-7Hz. Activity in the non-active limb emerged as the movement frequency requirements increased, irrespective of the direction of motion for the task (vertical, horizontal), hand used (preferred, non-preferred) or the auditory timing stimulus provided (metronome, no-metronome). The dynamics of the motor overflow in the non-active limb exhibited time- and frequency-dependent patterns similar to those of the active arm. Together, these results demonstrate that the high-frequency unilateral movements of one limb drives the emergence of motor outflow to the opposite limb with the motor output dynamics being produced across both limbs being progressively similar as movement speed increases.

PTMS11 Difference of phase-dependency between ipsi-and contra-motor cortex excitability during a unilateral finger phasic movement

PTMS11 Difference of phase-dependency between ipsi-and contra-motor cortex excitability during a unilateral finger phasic movement

On the regularity of preparatory activity preceding movements with the dominant and non-dominant hand: A readiness potential study

The readiness potential (RP), a slow negative electroencephalographic pre-movement potential, was reported to commence earlier for movements with the non-dominant left hand than with the dominant right hand. Latencies in these reports were always calculated from averaged RPs, whereas onset times of individual trials remained inaccessible. The aim was to use a new statistical approach to examine whether a few left hand trials with very early pre-movement activity disproportionally affect the onset of the average. We recorded RPs in 28 right-handed subjects while they made self-paced repetitive unilateral movements with their dominant and non-dominant hand. Skewness, a measure of distribution asymmetry, was analysed in sets of single-trial RPs to discriminate between a symmetric distribution and an asymmetric distribution containing outlier trials with early onset. Results show that for right hand movements skewness has values around zero across electrodes and pre-movement intervals, whereas for left hand movements skewness has initially negative values which increase to neutral values closer to movement onset. This indicates a symmetric (e.g., Gaussian) distribution of onset times across trials for simple right hand movements, whereas cortical activation preceding movements with the non-dominant hand is characterised by outlier trials with early onset of negativity. These findings may explain differences in the averaged brain activation preceding dominant versus non-dominant hand movements described in previous electrophysiological/neuroimaging studies. The findings also constrain mental chronometry, a technique that makes conclusions upon the time and temporal order of brain processes by measuring and comparing onset times of averaged electroencephalographic potentials evoked by these processes.

Nesting of asymmetric functions in skilled bimanual action: Dynamics of hammering behavior of bead craftsmen

In human manual activities, the two hands are often engaged in differentiated roles while cooperating with each other to produce an integrated outcome. Using recurrence methods, we studied the asymmetric bimanual action involved in stone bead production by craftsmen of different skill levels, and examined (a) how the control of unilateral movement is embedded in that of a bimanual system, and (b) how the behavior of a bimanual system is embedded in the context of the function performed in the world. Evidence was found that the movements of the two hands of experts were functionally linked, reflecting the roles assumed by each hand. We further found that only the dynamics of bimanual coordination of experts differentiated the functional requirements of different sub-goals. These results suggest that expertise in this skilled bimanual action lies in the nesting of functionally specific adjustments at different levels of a control hierarchy.

The Analysis of Handgrip Force during Bilateral and Unilateral Arm Movements in Different Directions: A Preliminary Study

The Analysis of Handgrip Force during Bilateral and Unilateral Arm Movements in Different Directions: A Preliminary Study

Dual-Task Demands of Hand Movements for Adults with Stroke: A Pilot Study

For adults with stroke, walking while performing a cognitive task can be challenging, resulting in slower walking, poorer cognitive performance, or decreased performance on both tasks. It is not known if dual-task deficits are also present for upper limb movements for adults with stroke. Purpose: To determine if unilateral movements of the affected and less affected hand are compromised when walking or talking. Methods: Nineteen community-dwelling adults with stroke were video- and audiotaped while performing in single- and dual-task conditions. Tasks included repeated, rhythmic hand movements with the affected and less affected hand, walking a narrow pathway, and speaking. For dual-task conditions, movements of each hand were done while walking and while talking. The rate of hand movement, cadence, and speech rate were analyzed using repeated measures analyses of variance. Results: Affected hand movement rate was the same for single- and dual-task conditions. The rate of less affected hand movement was affected by dual-task conditions; this was due to an increase in hand movement rate while talking. Examination of cadence and speech rates revealed that cadence was decreased when moving the affected hand. Speech rate increased when accompanied by hand movements, but post hoc analyses were not significant. Conclusion: For those with stroke, dual-task deficits are seen with slower walking while moving the affected hand. In contrast, hand movements while speaking may have a more complex relationship, with possible faster speech rates in dual-task conditions.

Neural control of joint stability during a ballistic force production task

Changes in transmission in Ia afferent and corticospinal pathways have been reported to depend on various factors including task complexity and the phase of movement. Here, we test whether a unilateral voluntary force production task leads to specific changes in both Ia afferent (by the use of the H-reflex technique) and corticospinal (by the use of transcranial magnetic stimulation, TMS) pathways in response to different mechanical conditions. The participants were exposed to either one or three mechanical degrees of freedom (DoF) of an external object while performing a unilateral knee extension movement in a sitting posture. The amplitudes of the m. soleus (SOL) EMG to either type of stimulation were normalized to amplitudes obtained during voluntary tonic contractions at matched background EMG in order to assess movement-related alterations. The results at two phases during movement (initial phase and during task execution) were analyzed. The unstable 1 DoF condition led to elevated co-contraction of SOL and the tibialis anterior muscle. Phase- and movement-related modulations of muscle responses to both types of stimulation were present in both mechanical conditions. However, the stable 1 DoF condition caused a significant facilitation of normalized H-reflexes in the initial phase of movement as compared to 3 DoF (1 DoF: 206%, 3 DoF: 96%, P<0.001). Conversely, larger normalized amplitudes in response to TMS were found in the initial phase of the 3 DoF condition as compared to 1 DoF (1 DoF: 107%, 3 DoF 160%, P<0.001). Additionally, during task execution the normalized amplitudes of TMS and H-Reflex testing revealed a relative decrease when compared to the initial phase of movement. It is suggested that presynaptic mechanisms caused the changes in the normalized H-reflexes (and thus in Ia afferent transmission) and that altered normalized responses to TMS reflect changes in corticospinal transmission. Consequently, we reason that the transmission in both pathways is sensitive to the nature of the mechanical interaction and thus to biomechanical task demands. Finally, the voluntary nature of the task might have caused a decisive influence of anticipatory control mechanisms triggered by advance information about the modality of environmental dynamics.

Recession of three muscles to reduce ocular oscillations in patients with Heimann-Bielschowsky phenomenon

Heimann-Bielschowsky phenomenon (HBP) refers to unilateral vertical nystagmoid eye movements associated with long-standing monocular poor vision. The monocular vertical oscillations of HBP occasionally have large amplitudes and may be cosmetically objectionable and/or functionally disturbing. We report 2 cases of HBP in which recession of the superior rectus, inferior rectus, and inferior oblique muscles were successful in ameliorating the amplitude of oscillations.

Using Squat Testing to Predict Training Loads for Lower-Body Exercises in Elite Karate Athletes

The purpose of this study was to determine the relationship between squat loads and 2 bilateral and 2 unilateral stepping lower-body exercises in predominantly unilateral movement elite athletes (Karate). Equations to predict loads for lower-body exercises based on the squat load were also determined. Fourteen male elite Karate athletes (age = 22.6 ± 1.2 years) performed 6 repetition maximum (RM) of the following free-weight bilateral exercises: back half squat, deadlift, leg press and unilateral stepping exercises, lunge; and step-up. Results showed that 6RM squat load was significantly (p < 0.001) correlated with deadlift (r = 0.86), leg press (r = 0.76), lunge (r = 0.86), and step-up (r = 0.92). Linear regression showed that the 6RM squat load was a significant predictor for deadlift, leg press, lunge, and step-up (R2 range from 0.57 to 0.85, p < 0.001). The following 6RM prediction equations were determined: (a) Deadlift = squat load (1.12)-16.60 kg, (b) Leg press = squat load (1.66) + 16.10 kg, (c) Lunge = squat load (0.61) + 9.39 kg, and (d) step-up = squat load (0.85)-10.36 kg. Coaches and fitness professionals can use the 6RM squat load as a time effective and accurate method to predict training loads for both bilateral and unilateral lower-body exercises with quadriceps as the prime mover. Load prescriptions for unilateral exercises should take into account the type of athletic population.

P20-4 Changes of interhemispheric inhibition and intracortical inhibition induced with bilateral and unilateral finger movement in healthy adults

P20-4 Changes of interhemispheric inhibition and intracortical inhibition induced with bilateral and unilateral finger movement in healthy adults

Poster 50: Control of a Robotic Aid to Manipulation by Myoelectric Signals in Spinal Cord Injury Subjects

Objective: To test the reliability and the accuracy of movement classifier based on electromyographic (EMG) signals of residual muscles of the upper-body spinal cord injury subjects. These movements will serve to control a robotic aid to manipulation. Design: Randomized, prospective study. Setting: Laboratory of imaging and orthopedics at the École de technologie supérieure. Participants: 30 subjects in total, 15 with spinal cord injury (level C4-C6) and 15 able-bodied subjects, aged from 18 to 65 years of age. Interventions: Participants perform a series of elementary and sequential movements of the upper body such as head rotations, shoulder elevation and depression, and elbow flexion. Main Outcome Measures: During each movement series, 8 EMG muscles activities were collected. For each EMG channel 6 features were extracted based on energy and autoregressive modeling approach. These features were inputted into a linear discriminant analysis (LDA) classifier. The main outcome measure is the performance of LDA classifier in order to recognize elementary and complex sequence of movement based only on EMG feature data. Result: Preliminary results obtained from 3 able-bodied subjects show that the performance of LDA was about 85% for 12 classified movements using the best learning sequences. The classifier's performance may be enhanced by diminishing the number of classified movements from 12 to 8. The performance of the LDA increases then to 95% with unilateral movements only. Conclusions: It is possible to achieve good classification performance by adapting the learning sequences and best classified movements to each subject.

A magnetoencephalographic study of sensorimotor activity differences during unilateral and bilateral forearm movements

This study compared activation of the sensorimotor area using magnetoencephalography after unilateral and bilateral movements. Thirteen healthy individuals and a patient with mild hemiplegia performed unilateral and bilateral forearm pronation movements. Among healthy participants, there were no significant differences in motor-evoked field during unilateral and bilateral movements, and equivalent current dipoles were located around the sensorimotor area. In the patient, motor-evoked field was measured in the lesional hemisphere clearly during bilateral movements, and the locus of equivalent current dipoles was estimated to be around the mean location in healthy individuals. In contrast, unilateral movements were estimated outside the area of sensorimotor activation. We speculate that bilateral movements may be more effective for functional recovery during rehabilitation.

Movement disorders associated with moyamoya disease: A report of 4 new cases and a review of literatures

The aim of this study was to define the clinical characteristics of patients who developed movement disorders in association with moyamoya disease (MMD). Using PubMed and medical records of our hospital from 1985 to 2008, we searched for patients who developed movement disorders in association with MMD. This study included 38 patients described in previous studies and 4 patients found in the medical records. The onset of movement disorders was thought to be sudden. In 13 patients, the movement disorders were precipitated by hyperventilation or emotional stress. Twenty-seven of the 42 patients developed chorea, 4 patients developed dystonia, and 4 developed a mixture of both. The movement disorders of the remaining 7 patients were described as dyskinesia. A third of the 42 patients developed bilateral movement disorders, and their mean age was younger than that of those with unilateral movement disorders. In 37 of the 42 patients, brain imaging studies showed ischemic lesions, but the remaining 5 patients showed no parenchymal lesions. Cerebral perfusion studies showed hypoperfusion in the basal ganglia and in the cerebral cortical areas. Most patients improved whether they were treated or not. MMD must be included in the differential diagnosis of the sudden onset of dyskinesias, particularly chorea and focal dystonia. Even in patients with no parenchymal lesion in brain imaging studies, cerebral angiography and cerebral blood perfusion studies must be performed, if they develop a sudden onset or recurrent movement disorders preceded by emotional stress or hyperventilation.

High Gamma Oscillations of Sensorimotor Cortex During Unilateral Movement in the Developing Brain: a MEG Study

Recent studies in adults have found consistent contralateral high gamma activities in the sensorimotor cortex during unilateral finger movement. However, no study has reported on this same phenomenon in children. We hypothesized that contralateral high gamma activities also exist in children during unilateral finger movement. Sixty normal children (6-17years old) were studied with a 275-channel MEG system combined with synthetic aperture magnetometry (SAM). Sixty participants displayed consistently contralateral event-related synchronization (C-ERS) within high gamma band (65-150Hz) in the primary motor cortices (M1) of both hemispheres. Interestingly, nineteen younger children displayed ipsilateral event-related synchronization (I-ERS) within the high gamma band (65-150Hz) just during their left finger movement. Both I-ERS and C-ERS were localized in M1. The incidence of I-ERS showed a significant decrease with age. Males had significantly higher odds of having ipsilateral activity compared to females. Noteworthy, high gamma C-ERS appeared consistently, while high gamma I-ERS changed with age. The asymmetrical patterns of neuromagnetic activities in the children's brain might represent the maturational lateralization and/or specialization of motor function. In conclusion, the present results have demonstrated that contralateral high-gamma neuromagnetic activities are potential biomarkers for the accurate localization of the primary motor cortex in children. In addition, the interesting finding of the ipsilateral high-gamma neuromagnetic activities opens a new window for us to understand the developmental changes of the hemispherical functional lateralization in the motor system.

Negative BOLD during tongue movement: A functional magnetic resonance imaging study

The aim of this functional magnetic resonance imaging (fMRI) study was to evaluate negative blood oxygen level-dependent (BOLD) signals during voluntary tongue movement. Deactivated (Negative BOLD) regions included the posterior parietal cortex (PPC), precuneus, and middle temporal gyrus. Activated (Positive BOLD) regions included the primary somatosensory-motor area (SMI), inferior parietal lobule, medial frontal gyrus, superior temporal gyrus, insula, lentiform nucleus, and thalamus. The results were not consistent with previous studies involving unilateral hand and finger movements showing the deactivation of motor-related cortical areas including the ipsilateral MI. The areas of Negative BOLD in the PPC and precuneus might reflect specific neural networks relating to voluntary tongue movement.

Generalization of visuomotor learning between bilateral and unilateral conditions.

A long history of behavioral and physiological research has suggested that bilateral coordination invokes unique neural processes that are not involved in unilateral movements. This hypothesis predicts that motor learning should show limited transfer between unilateral and bilateral conditions, which is consistent with a recent finding that indicated partial, but not complete, transfer of learning between the two conditions. However, during learning of new motor skills, transformations must also be made between visual and proprioceptive coordinate systems, a process that may occur upstream to the processes that differentiate bilateral from unilateral movements. We now investigate whether visuomotor adaptations are shared between unilateral and bilateral movement conditions. Our results indicate substantial transfer from bilateral to subsequent unilateral conditions for both arms. Interestingly, whereas the nondominant arm never showed complete adaptation to visual rotation under bilateral conditions, this interference, or lack of improvement, in bilateral performance did not disturb the visuomotor adaptation process or transfer, as reflected by superb unilateral performances immediately following the bilateral conditions. These findings unambiguously indicate that visuomotor adaptation can extensively generalize between bilateral and unilateral conditions, thus suggesting a substantial overlap in the neural processes underlying visuomotor transformations between the two movement conditions. Our findings provide support for a two-stage model of motor planning, in which the visuomotor transformation process precedes the processes that convert the visuomotor plan into effector-specific commands that incorporate bilateral synergies and that result in the forces that determine motion.