1,721,050 research outputs found
Quantitative EEG evaluation during robot-assisted foot movement
Full text linkPassive and imagined limb movements induce changes in cerebral oscillatory activity. Central modulatory effects play a role in plastic changes, and are of uttermost importance in rehabilitation. This has extensively been studied for upper limb, but less is known for lower limb. The aim of this study is to investigate the topographical distribution of event-related desynchronization/synchronization (ERD/ERS) and task-related coherence during a robot-assisted and a motor imagery task of lower limb in healthy subjects to inform rehabilitation paradigms. 32-channels electroencephalogram (EEG) was recorded in twenty-one healthy right footed and handed subjects during a robot-assisted single-joint cyclic right ankle movement performed by the BTS ANYMOV robotic hospital bed. Data were acquired with a block protocol for passive and imagined movement at a frequency of 0.2 Hz. ERD/ERS and task related coherence were calculated in alpha1 (810 Hz), alpha2 (10.512.5 Hz) and beta (1330 Hz) frequency ranges. During passive movement, alpha2 rhythm desynchronized over C3 and ipsilateral frontal areas (F4, FC2, FC6); beta ERD was detected over the bilateral motor areas (Cz, C3, C4). During motor imagery, a significant desynchronization was evident for alpha1 over contralateral sensorimotor cortex (C3), for alpha2 over bilateral motor areas (C3 and C4), and for beta over central scalp areas. Task-related coherence decreased during passive movement in alpha2 band between contralateral central area (C3, CP5, CP1, P3) and ipsilateral frontal area (F8, FC6, T8); beta band coherence decreased between C3-C4 electrodes, and increased between C3-Cz. These data contribute to the understanding of oscillatory activity and functional neuronal interactions during lower limb robot-assisted motor performance. The final output of this line of research is to inform the design and development of neurorehabilitation protocols
Lack of inter-muscular coherence of axial muscles in Pisa syndrome
No full textPisa syndrome is a lateral deviation of the trunk described in Parkinson's disease (PD). Its etiology is still unknown; advanced muscular signal analysis techniques, such as inter-muscular coherence, could help clarifying its pathophysiology and suggest therapeutic strategies.
METHODS:
Fourteen idiopathic PD subjects with a lateral deviation of the trunk of at least 10° were included. Electromyographic (EMG) signal was recorded from bilateral thoracic, and lumbar para-spinal and obliqui externi muscles. The synchronization between EMG right and left side signals was quantified using the magnitude-squared coherence function.
RESULTS:
In our sample, coherence (range 0-1) did not exceed 0.3, which indicates a lack of intra-muscular coherence.
CONCLUSION:
This finding is suggestive of a defective muscular fine-tuning, which has been associated with bradykinesia. These data support the hypothesis of PS as a clinical sign of bradykinesia, impacting on therapeutic and rehabilitative options
Exoskeleton Training Modulates Complexity in Movement Patterns and Cortical Activity in Able-Bodied Volunteers
Full text link: Robot-aided gait training (RAGT) plays a crucial role in providing high-dose and high-intensity task-oriented physical therapy. The human-robot interaction during RAGT remains technically challenging. To achieve this aim, it is necessary to quantify how RAGT impacts brain activity and motor learning. This work quantifies the neuromuscular effect induced by a single RAGT session in healthy middle-aged individuals. Electromyographic (EMG) and motion (IMU) data were recorded and processed during walking trials before and after RAGT. Electroencephalographic (EEG) data were recorded during rest before and after the entire walking session. Linear and nonlinear analyses detected changes in the walking pattern, paralleled by a modulation of cortical activity in the motor, attentive, and visual cortices immediately after RAGT. Increases in alpha and beta EEG spectral power and pattern regularity of the EEG match the increased regularity of body oscillations in the frontal plane, and the loss of alternating muscle activation during the gait cycle, when walking after a RAGT session. These preliminary results improve the understanding of human-machine interaction mechanisms and motor learning and may contribute to more efficient exoskeleton development for assisted walking
Assessment of Event-Related EEG Power After Single-Pulse TMS in Unresponsive Wakefulness Syndrome and Minimally Conscious State Patients
Full text linkIn patients without a behavioral response, non-invasive techniques and new methods of data analysis can complement existing diagnostic tools by providing a method for detecting covert signs of residual cognitive function and awareness. The aim of this study was to investigate the brain oscillatory activities synchronized by single-pulse transcranial magnetic stimulation (TMS) delivered over the primary motor area in the time-frequency domain in patients with the unresponsive wakefulness syndrome or in a minimally conscious state as compared to healthy controls. A time-frequency analysis based on the wavelet transform was used to characterize rapid modifications of oscillatory EEG rhythms induced by TMS in patients as compared to healthy controls. The pattern of EEG changes in the patients differed from that of healthy controls. In the controls there was an early synchronization of slow waves immediately followed by a desynchronization of alpha and beta frequency bands over the frontal and centro-parietal electrodes, whereas an opposite early synchronization, particularly over motor areas for alpha and beta and over the frontal and parietal electrodes for beta power, was seen in the patients. In addition, no relevant modification in slow rhythms (delta and theta) after TMS was noted in patients. The clinical impact of these findings could be relevant in neurorehabilitation settings for increasing the awareness of these patients and defining new treatment procedures
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
EEG markers of improved proprioception and posture in older women with osteoporosis
No full textThe age-related decline in proprioception contributes to poor balance and motor coordination, increasing the risk of falls. Ten female participants (> 65 years) with osteoporosis underwent the Mini Balance Evaluation System test before (T0) and after (T1) a three-week programme involving the application of neuro-muscular taping to the lumbar, rhomboid and gastrocnemius muscles, alongside 15 minutes of simple physical exercises each day to improve proprioception. High-density electroencephalography (EEG) data were collected during the sensory orientation tasks, i.e., standing with eyes open or closed on solid and foam surfaces. Changes in spectral power over time (T0, T1) and across tasks were assessed using linear mixed effects regression models. Participants showed a significant increase in absolute theta power (p < 0.001) and a decrease in absolute beta power (p < 0.001) at T1, compared to T0. When standing on the foam, there was a significant decrease in both theta (p < 0.001) and alpha (p < 0.01) absolute power values at T0, with the decrease in theta being significantly attenuated by T1 (p < 0.001). The EEG results, together with improvements in balance test scores, suggest that participants experienced improved attentional control to monitor and maintain balance
Experimental protocol to investigate cortical, muscular and body representation alterations in adolescents with idiopathic scoliosis
Full text linkBackground: Adolescent idiopathic scoliosis (AIS) is the most common form of scoliosis. AIS is a three-dimensional morphological spinal deformity that affects approximately 1-3% of adolescents. Not all factors related to the etiology of AIS have yet been identified. Objective: The primary aim of this experimental protocol is to quantitatively investigate alterations in body representation in AIS, and to quantitatively and objectively track the changes in body sensorimotor representation due to treatment. Methods: Adolescent girls with a confirmed diagnosis of mild (Cobb angle: 10°-20°) or moderate (21°-35°) scoliosis as well as age and sex-matched controls will be recruited. Participants will be asked to perform a 6-min upright standing and two tasks-named target reaching and forearm bisection task. Eventually, subjects will fill in a self-report questionnaire and a computer-based test to assess body image. This evaluation will be repeated after 6 and 12 months of treatment (i.e., partial or full-time brace and physiotherapy corrective postural exercises). Results: We expect that theta brain rhythm in the central brain areas, alpha brain rhythm lateralization and body representation will change over time depending on treatment and scoliosis progression as a compensatory strategy to overcome a sensorimotor dysfunction. We also expect asymmetric activation of the trunk muscle during reaching tasks and decreased postural stability in AIS. Conclusions: Quantitatively assess the body representation at different time points during AIS treatment may provide new insights on the pathophysiology and etiology of scoliosis
Effect of high-frequency repetitive transcranial magnetic stimulation on brain excitability in severely brain-injured patients in minimally conscious or vegetative state
Full text linkBACKGROUND:
Repetitive transcranial magnetic stimulation (rTMS) induces prolonged functional changes in the cerebral cortex in normal conditions and in altered states of consciousness. Its therapeutic effects have been variously documented.
OBJECTIVE:
The aim of this study was to investigate the reactivity of electroencephalography (EEG) and the clinical response in six severely brain-injured patients in an altered state of consciousness (minimally conscious state [MCS] or vegetative state [VS]). EEG rhythm and brain excitability were measured before and after a protocol of high-frequency rTMS.
METHODS:
All six patients underwent clinical and neurophysiological evaluation before rTMS and immediately thereafter. EEG data in resting state were acquired at the beginning of the exam (T0), after rTMS (T1), and 38 min after rTMS (T2). From these data the power values were computed using Fast Fourier Transform.
RESULTS:
rTMS over the motor cortex induced long-lasting behavioral and neurophysiological modifications in only one patient in MCS. No significant clinical or EEG modifications were detected in any of the other patients, except for changes in motor threshold and motor evoked potential amplitude over the stimulated motor areas.
CONCLUSIONS:
The main finding of the study is the correlation between EEG reactivity and clinical response after rTMS. Reappearance of fast activity and an increase in slow activity were noted in the one patient with transitory arousal, whereas no significant reliable changes were observed in the other patients showing no clinical reactivity
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