The combined action of a passive exoskeleton and an EMG-controlled neuroprosthesis for upper limb stroke rehabilitation: First results of the RETRAINER project.

The combined use of Functional Electrical Stimulation (FES) and robotic technologies is advocated to improve rehabilitation outcomes after stroke. This work describes an arm rehabilitation system developed within the European project RETRAINER. The system consists of a passive 4-degrees-of-freedom exoskeleton equipped with springs to provide gravity compensation and electromagnetic brakes to hold target positions. FES is integrated in the system to provide additional support to the most impaired muscles. FES is triggered based on the volitional EMG signal of the same stimulated muscle; in order to encourage the active involvement of the patient the volitional EMG is also monitored throughout the task execution and based on it a happy or sad emoji is visualized at the end of each task. The control interface control of the system provides a GUI and multiple software tools to organize rehabilitation exercises and monitor rehabilitation progress. The functionality and the usability of the system was evaluated on four stroke patients. All patients were able to use the system and judged positively its wearability and the provided support. They were able to trigger the stimulation based on their residual muscle activity and provided different levels of active involvement in the exercise, in agreement with their level of impairment. A randomized controlled trial aimed at evaluating the effectiveness of the RETRAINER system to improve arm function after stroke is currently ongoing.

Gait analysis of pre- and post-meniscectomy knee: a prospective study.

Degenerative changes in the knee joint after meniscectomy are well known. Although likely to be due to changed biomechanics, there is no evidence in the literature to identify the underlying biomechanical alterations. The aim of this study was to analyse lower limb gait biomechanics before and after meniscectomy. Ten patients who required partial medial meniscectomy for irreparable meniscal tear took part in motion analysis before surgery, then at 6 and 12 months post-operatively. A control group was also set up consisting of 10 healthy volunteers. Joint kinematics did not show significant alterations between pre-operative and 6 month post-operative evaluations. However flexion increases at the hip, knee and ankle joint were observed in late swing and early stance phase 12 months after surgery. Hip and knee flexion-extension moments were affected with knee moment altered both before and after surgery. Before surgery and at 6 months after, the changes occurred mainly at the point of push off, while at 12 months they occurred during the swing phase. Hip flexion-extension moment had also changed 12 months after surgery. When examining symmetry of gait patterns prior to surgery, there were differences between the flexion-extension moments of the healthy and of the injured knee at first impact and during late stance. After surgery, asymmetries were not more apparent at first impact, but in late stance phase a reduced knee extension moment in the injured limb was still present. Before surgery, the joint kinematics were not greatly altered and changes were mainly due to pain. After partial meniscectomy, the pain disappeared and new joint responses were observed. These could be caused by the altered mechanics and/or through proprioceptive mechanisms.

3D kinematic analysis and clinical evaluation of neck movements in patients with whiplash injury.

In recent decades whiplash injuries, being a major reason for compensation claims, have become increasingly important in forensic medicine. In view of this, a reliable diagnostic method of assessing cervical range of motion (ROM) is needed. The aim of the present study was to evaluate neck function with a 3D kinematic method compared with clinical evaluation in whiplash injury. Seventy consecutive patients (M/F = 18/52) with a history of whiplash injury (WH) and 46 healthy volunteers (M/F = 24/22), mean age, respectively 33 +/- 9 and 28 +/- 6 years (mean+/-SD) entered the study. Patients suffered from neck pain and/or unilateral headache. A computerized kinematic analysis of the ROM (Elite system) using passive markers and two infrared TV cameras was used. Clinical evaluation of active ROM was also performed both in patients and in 61 controls (M/F = 23/38; mean age 47 +/- 18 years). Thirty out of 70 patients were tested at the time of their first consultation (T0) and 6 months later (T6), and 12 were also followed up after a year (T12). All neck movements, except extension, were significantly reduced in WH subjects compared with controls, in particular lateral bending. Comparing ROM at T0, T6 and T12, no significant differences were found. A global index of motion (GIM), obtained by calculating the sum of ROM in absolute value for all the movements acquired, was significantly reduced in WH compared with control subjects. The interobserver reliability of the clinical evaluation was globally acceptable. On the basis of the clinical evaluation, a significantly reduced ROM was found in all movements in WH subjects compared with an age-matched population. Computing the number of impaired cervical movements (ICMs), a significantly higher number was observed in WH patients than in controls, showing a decreasing trend at T6 and T12, with a significant improvement at T6 vs. T0. The computerized study of neck ROM may constitute a useful tool in the evaluation of WH at baseline and follow-up.

The position of the head in space: a kinematic analysis in patients with cervical dystonia treated with botulinum toxin.

Many instruments have been employed in recent years in order to quantify the posture and motion of the head in normal and pathological subjects. Evaluations of this type present many difficulties related to the influence of individual and external factors and to the accuracy of the system used. In patients with cervical dystonia (CD) the only rating scales currently used are semi-quantitative and subjective. More precise information on disease severity and response to the treatment is needed. Posture and motion of the head were evaluated by means of ELITE motion analyser (BTS, Milan, Italy) in 6 patients with the left laterocollis form of CD undergoing treatment with botulinum toxin (BTX). The method emerged as very useful for the quantification of the therapeutic response (which was more marked in motion than in posture). We found an inverse relationship between the degree of motion improvement and the restriction of motion before treatment.

Botulinum toxin treatment for functional disability induced by essential tremor.

This study aimed to improve botulinum toxin's (BTX) efficacy and to reduce its unwanted effects in the treatment of functional disability due to essential tremor (ET) of the hand. Twenty patients with disabling ET, not responding to conventional pharmacological therapy, were enrolled in this open-label study. Activities of daily living self-questionnaire (ADLS) and severity tremor scale (STS) were used to establish patients' functional disability and tremor severity. Accelerometry and surface electromyography were used to identify the arm muscles with tremorogenic activity during impaired positions. Global rating was used to measure treatment efficacy and unwanted effects. BTX type A was injected into the muscles principally responsible for impaired positions. After BTX treatment, there was a significant reduction in both severity and functional rating scales scores (ADLS and STS) and of tremor amplitude as measured with accelerometry and EMG. Adverse effects were limited to a slight third finger extension weakness in 15% of patients. BTX injections are effective and safe in reducing disability due to ET, if based on the criterion of functional selection.

A 3D kinematic method for evaluating voluntary movements of the cervical spine in humans.

The purpose of this study was to assess the reliability of a 3D kinematic method of evaluating movements of the cervical spine. Range of motion (ROM) of the cervical spine was evaluated in 8 control subjects during flexion-extension, rotation and lateral bending movements. The test was repeated on two separate occasions. The ROM test-retest difference ranged from 1.42 degrees for right axial rotation to 9.11 degrees for left axial rotation. The test showed good reliability, with an intraclass correlation coefficient which was higher than 0.74 in extension movement and excellent in flexion, axial rotation and lateral bending. In conclusion, the method proposed for the 3D kinematic analysis of neck movement proved to be useful and non-invasive and to show good-excellent reproducibility. Furthermore the method is easily applicable in clinical practice to evaluate neck function in cervical spine disorders.

Gait patterns after anterior cruciate ligament reconstruction.

The aim of this study is to analyse the changes in select gait parameters following anterior cruciate ligament (ACL) reconstruction. The study was performed on 15 subjects who underwent ACL reconstruction by the bone-patellar tendon-bone technique. Gait analysis was performed using the Elite three-dimensional (3D) optoelectronic system (BTS), a Kistler force platform and the Telemg telemetric electromyograph (BTS). Kinematic data were recorded for the principal lower limb joints (hip, knee and ankle). The examined muscles include vastus lateralis, rectus femoris, biceps femoris and semitendinosus. The results obtained from the operated subjects were compared with those of 10 untreated subjects and 5 subjects without ACL damage. In the operated subjects the knee joint angular values regained a normal flexion pattern for the injured limb during the stance phase. The analysis of joint moments shows: (a) sagittal plane: recovery of the knee flexion moment at loading response and during preswing; (b) frontal plane: recovery of the normal patterns for both hip and knee adduction-abduction moments during the entire stance phase. The examination of ground reaction forces reveals the recovery of frontal component features. The EMG traces show the normal biphasic pattern for the operated subjects as compared to the untreated subjects. The results suggest that the gait parameters shift towards normal value patterns.

Normal gait is differentially influenced by the otoliths.

Postural control depends on the integration of vestibular, somatosensory and visual orientation signals. The otolith contribution to postural control is achieved by the integration of otolith inputs and peripheral afferent inputs involved in crossed reflex pathways. This study shows that a functional linkage between otolith signals and activity in lower limb muscles is detectable in normal human gait. The otolith input appears to dominate particularly the neck proprioceptive and gaze motor influences during normal gait. This is demonstrated by an increase of tibialis anterior muscle activity during retroflexion of the head/neck, leading to an increased stability and counteracting possible perturbations. It is also shown by decrease of coordination during the movement caused by larger displacement of the centre of gravity demonstrated in vector diagrams.

Muscular effort and musculo-skeletal disorders in piano students: electromyographic, clinical and preventive aspects.

An investigation was made on the relationship between music practice and musculo-skeletal disorders among piano students, with the main aim of developing health education programmes that would improve the performance and health of the students. The investigation covered three areas: (a) Analysis of study organization and main musculo-skeletal complaints achieved by a questionnaire distributed to all piano students at the Milan Conservatory. (b) Vocational electromyographic analysis of the effort exerted by the various muscle groups of the trunk, of the shoulder and shoulder blade girdle, and of the arm during performance of a standard set of piano exercises, an unseen passage and a passage of maximum difficulty. This analysis was made on a sample of six subjects. (c) A series of preventive measures was developed on the basis of a critical assessment of the results (38% of the students practised for excessively long periods without breaks; 62% had from 1 to 5 complaints, the most affected sites being the spine and the trapezius muscles). These consisted largely of a health education programme aimed at helping the students to suitably organize practice and rest periods and in instructing them in appropriate exercises for relaxation and stretching of overused muscle groups and strengthening the supporting muscle groups. Changes in lifestyle were also suggested.