Upper and lower extremity robotic devices to promote motor recovery after stroke -recent developments

Successful motor rehabilitation of stroke, TBI and SCI subjects requires an intensive and task-specific therapy approach. Budget constrains limit a hand-to-hand therapy approach, so that intelligent machines may offer a solution to further promote motor recovery and to better understand motor control. This new field of automated or robot-assisted motor rehabilitation has emerged since the nineties. The article presents clinically viable devices for the upper and lower extremity rehabilitation, which have been developed by our group. The Bi-Manu-Track, enables the bilateral practice of a forearm and wrist movement, and is currently tested. For gait rehabilitation after stroke, the electromechanical gait trainer GT I has proven effective as compared to treadmill training with body weight support (BWS). The latest development is the HapticWalker, a robotic walking simulator for gait training, which allows the training of arbitrary daily life foot trajectories. The foot trajectories can be individually adjusted to each patient, in addition the machine will offer a sophisticated patient-machine-interaction. A prototype of the machine has been designed and built succesfully and is being evaluated at present. Technical possibilities are one aspect, but multi-centre trials and the consideration of unsubstantiated fears among therapists of being replaced by the machines will decide on the successful implementation of this most promising field to the benefit of patients.

Safety concept for robotic gait trainers

The work presents a newly developed safety concept for application of robotic walking simulators based on the principle of programmable footplates in gait rehabilitation. Unlike robotic hand devices or exoskeleton robots for gait training on treadmills, which can be built relatively lightweight and require only small drives which can hardly do harm to the patient, a programmable footplate walking simulator with permanent foot fixture essentially needs to have powerful drives in order to carry and move the full body weight of the patient. The developed safety concept comprises several redundant algorithms and devices in the real-time robot control software, electrical emergency stop circuitry and machine mechanics. The mechanical core is a machine design offering maximum passive security by covering all moving parts (i.e. robot drives and linkages) and a newly developed foot safety release binding, which is mounted on each footplate. The release binding allows a safe release from the footplate in all directions in any degree of freedom in the sagittal plane. It is combined with an ankle goniometer which is equipped with adjustable emergency stop limit switches, thus ensuring that the allowed ankle range-of-motion is not exceeded.

Combined transcranial direct current stimulation and robot-assisted arm training in subacute stroke patients: a pilot study

BACKGROUND AND PURPOSE

Preliminary reports suggest that central stimulation may enhance the effect of conventional physical therapies after stroke. This pilot study examines the safety and methodology of using transcranial direct stimulation (tDCS) with robot-assisted arm training (AT), to inform planning a larger randomised controlled trial.

SUBJECTS

Ten patients, after an ischaemic stroke 4-8 weeks before study onset, no history of epilepsy, participated. Eight had a cortical lesion and 2 had subcortical lesions: all had severe arm paresis and, co-incidentally, 5 had severe aphasia.

METHODS

Over six weeks, they received thirty 20 min-sessions of AT. During the first 7 minutes, 1.5mA of tDCS was applied, with the anode over the lesioned hemisphere and the cathode above the contralateral orbit. Arm and language impairment were assessed with the Fugl-Meyer motor score (FM, full range 0-66) and the Aachener Aphasie Test.

RESULTS

No major side effects occurred. Arm function of three patients (two with a subcortical lesion) improved significantly, with FM scores increasing from 6 to 28, 10 to 49 and 11 to 48. In the remaining seven patients, all with cortical lesions, arm function changed little, FM scores did not increase more than 5 points. Unexpectedly, aphasia improved in 4 patients.

CONCLUSIONS

These procedures are safe, and easy to use in a clinical setting. In future studies, patients should be stratified by degree of arm weakness and lesion site, also the unexpected aphasia improvement warrants following-up.

Tumeur vasculaire géante de l’adulte : angiome en touffe ou hémangioendothéliome kaposiforme

INTRODUCTION

Tufted angioma and kaposiform hemangioendothelioma are two rare benign but aggressive vascular tumours that occur mainly in children.

OBSERVATION

A 72 year-old man consulted for a 50 cm wide vascular tumour of the right shoulder which was increasing for 10 years. On histological examination there were features of tufted angioma and kaposiform hemangioendothelioma.

DISCUSSION

The tumour of this patient was atypical because of its big size never described before. The histological association of aspects which could correspond to tufted angioma and kaposiform hemangioendothelioma seems to confirm recent publications which support the hypothesis that these two tumours are two evolutive stages of one and only entity.

Possible impact of dopamine SPECT on decision-making for drug treatment in Parkinsonian syndrome

Single-photon emission computed tomography (SPECT) markers allow measuring the integrity of the brain dopaminergic system in vivo. We used dopamine transporter (DAT) SPECT with [(123)I]FP-CIT and dopamine D(2)/D(3) receptor SPECT with [(123)I]IBZM to evaluate whether there is a reduction of DAT and/or D(2)/D(3) receptor SPECT in treated and untreated patients with Parkinsonian syndrome (PS). We found that almost a quarter of our patients treated with anti-Parkinsonian medication prior to SPECT imaging did not show evidence of a presynaptic dopaminergic deficit while 37% of untreated patients were diagnosed as having Parkinson's disease. 17% of treated patients had additional loss of D(2)/D(3) receptor binding capacity in concordance with the clinical follow-up diagnoses of multiple system atrophy, progressive nuclear palsy, and vascular Parkinsonism. Apart from 38% clinically uncertain cases, SPECT was in concordance with 75% of initial clinical diagnoses. 25% were reclassified as indicated by SPECT findings and confirmed by a 1.5-year clinical follow-up. We conclude that dopamine SPECT may support establishing or refuting the clinical diagnosis and, therefore, help to make the decision for or against dopaminomimetic treatment in cases with PS.

[Mandatory continuing medical education: did the doctors follow the rule? A survey in the state of Vaud]

In 2000, after a deep controversy, the FMH decided to make continuous medical education (CME) compulsory for all physicians practicing in Switzerland. In this study we report the results of two surveys performed between 2000 and 2002 among physicians practicing in the state of Vaud. Our data show that the rule was successfully implemented by most practitioners, both primary care physicians and specialists. This led to a strong increase of the number of encounters between members of the profession as well as an improvement of the quality of the CME, thus showing the relevance of the measure.

Computerized Arm Training Improves the Motor Control of the Severely Affected Arm After Stroke

Background and Purpose— To compare a computerized arm trainer (AT), allowing repetitive practice of passive and active bilateral forearm and wrist movement cycle, and electromyography-initiated electrical stimulation (ES) of the paretic wrist extensor in severely affected subacute stroke patients.

Method— A total of 44 patients, 4 to 8 weeks after stroke causing severe arm paresis (Fugl–Meyer Motor Score [FM, 0 to 66] <18), were randomly assigned to either AT or ES. All patients practiced 20 minutes every workday for 6 weeks. AT patients performed 800 repetitions per session with the robot and ES patients performed 60 to 80 wrist extensions per session. The primary outcome measure was the blindly assessed FM (0 to 66), and the secondary measures were the upper limb muscle power (Medical Research Council [MRC] sum, 0 to 45) and muscle tone (Ashworth score sum, 0 to 25), assessed at the beginning and end of treatment and at 3-month follow-up.

Results— The AT group had a higher Barthel Index score at baseline, but the groups were otherwise homogenous. As expected, FM and MRC sum scores improved overtime in both groups but significantly more in the robot AT group. The initial Barthel Index score had no influence. In the robot AT group, FM score was 15 points higher at study end and 13 points higher at 3-month follow-up than the control ES group. MRC sum score was 15 points higher at study end and at 3-month follow-up compared with the control ES group. Muscle tone remained unchanged, and no side effects occurred.

Conclusion— The computerized active arm training produced a superior improvement in upper limb motor control and power compared with ES in severely affected stroke patients. This is probably attributable to the greater number of repetitions and the bilateral approach.

D2 dopamine receptor occupancy, risperidone plasma level and extrapyramidal motor symptoms in previously drug-free schizophrenic patients

RATIONALE

A relationship between high D2 occupancy (above 80%) and extrapyramidal-motor symptoms under neuroleptic treatment has been observed in several neuroimaging studies.

OBJECTIVES

We investigated the striatal dopamine D2 receptor occupancy, risperidone plasma level and extrapyramidal-motor symptoms in drug-free schizophrenic patients.

METHODS

Ten schizophrenic patients were treated with 3 - 6 mg risperidone daily. After four weeks administration, a [(123)I]iodobenzamide ([(123)I]IBZM)-single photon emission tomography (SPET) scan for determination of D2 receptor occupancy was carried out (in eight responders) and compared to a control group. Plasma concentrations of risperidone and its active metabolite 9-hydroxyrisperidone (active moiety) were determined by high performance liquid chromatography and electrochemical detection. Extrapyramidal-motor symptoms were assessed by means of the Simpson-Angus-Scale and a handwriting test before treatment and coincident with the scan.

RESULTS

The D2 receptor occupancy (Mean 62%, SD 13%) positively correlated with the plasma level of the risperidone active moiety as well as with the reduction in handwriting area. Multiple linear regression revealed an inherent relationship with a coefficient of determination of r = 0.956 (p = 0.02). No clinical relevant extrapyramidal-motor symptoms were observed.

CONCLUSIONS

In drug-free schizophrenic responders, the simultaneous assessment of both plasma level and reduction in handwriting area may be a useful clinical tool for a surrogate estimate of D2 receptor occupancy under risperidone treatment. This may help to minimize or even prevent extrapyramidal-motor symptoms.

High negative predictive value of slow lymphatic drainage on metastatic node spread detection in malignant limb and trunk cutaneous melanoma

AIM

Harvesting of the "sentinel lymph node" (SLN) as identified by lymphoscintigraphy (LSG) is becoming increasingly important in the staging of patients with malignant melanoma. The purpose of the current study was to determine whether the appearance time of the LSG had a prognostic value in predicting metastasis dissemination in thick cutaneous malignant melanoma.

METHODS

Between July 1999 and July 2003, 88 consecutive patients with histologically proven melanoma with a Breslow's thickness > 1 mm, without clinical or radiological evidence of lymph node involvement or metastasis, prospectively underwent lymphoscintigraphy with 32 Mbq Tc 99m sulfur colloid prior to sentinel lymphadenectomy with sentinel lymph node (SLN) histological examination.

RESULTS

LSG was performed in 88 patients with limb and trunk melanoma and identified a total of 149 sentinel nodes. Pathological examination revealed lymph node involvement in 21 patients (24%). All positive SLNs were imaged with a scintigraphic appearance time of less than 30 min. With a scintigraphic appearance time greater than 30 min, the negative predictive value (NPV) of spread in the SLN was 100% (27/27)(CI 87-100%).

CONCLUSION

The strong NPV of LSG in identifying "slow" sentinel lymph nodes in patients with no clinical evidence of lymph node involvement suggests that patients could be spared sentinel lymph node biopsy when LSG detects "slow" sentinel lymph nodes. Another prospective study will be required to confirm that the scintigraphic appearance time of sentinel lymph nodes is an important predictive parameter of metastatic disease in sentinel lymph nodes and consequently might reduce the number of sentinel lymph node biopsies.

Pr�operative Bildgebung

With the progressive development of soft- and hardware, the acceptance of image-guided neurosurgery has increased dramatically. Additional image data are required to analyze the nature and the dimensions of pathological processes and the surrounding tissue. In this context, fMRI, SPECT, PET, as well as special modalities of CT and MR imaging, are routinely used. Secondary post-processing options are used to detect intracerebral lesions as well as adjacent functional eloquent regions in the parenchymatous organ pre- and intraoperatively. The integration of different image information guarantees the precise planning and realization of surgical maneuvers. The segmentation of interesting structures and risk structures, as well as their implementation in the neuronavigation systems, help to avoid additional intraoperative traumatization and offer a higher level of safety and precision. In this article the value and limitations of presurgical imaging will be discussed.

[Development of a robotic walking simulator for gait rehabilitation]

Restoration of gait is a major concern of rehabilitation after stroke or spinal cord injury. Modern concepts of motor learning favour a task-specific repetitive approach, i.e. "whoever wants to learn to walk again must walk." However, the physical demands this places on the therapist, is a limiting factor in the clinical routine setting. This article describes a robotic walking simulator for gait training that enables wheelchair-bound subjects to freely carry out repetitive practicing of an individually adapted gait pattern under simulation of the manual guidance of an experienced therapist. The technical principle applied makes use of programmable footplates with permanent foot/machine contact in combination with compliance control. The solution chosen comprises a planar parallel-serial hybrid kinematic system with three degrees of freedom that moves the feet in the sagittal plane. Gait analysis while floor walking and stair climbing, clinical practicability and safety aspects were the basis for the design. A variable compliance control enables man-machine interaction, ranging from purely position controlled movement to full compliance during swing phase above a virtual ground profile. In full compliance mode the robotic walking simulator behaves like a haptic device. The concept presented offers new prospects for individualized gait rehabilitation.