Biomechanical analysis of body movements of myoelectric prosthesis users during standardized clinical tests

Objective: The objective clinical evaluation of user's capabilities to handle their prosthesis is done using various tests which primarily focus on the task completion speed and do not explicitly account for the potential presence of compensatory motions. Given that the excessive body compensation is a common indicator of inadequate prosthesis control, tests which include subjective observations on the quality of performed motions have been introduced. However, these metrics are then influenced by the examiner's opinions, skills, and training making them harder to standardize across patient pools and compare across different prosthetic technologies. Here we aim to objectively quantify the severity of body compensations present in myoelectric prosthetic hand users and evaluate the extent to which traditional objective clinical scores are still able to capture them. Methods: We have instructed 9 below-elbow prosthesis users and 9 able-bodied participants to complete three established objective clinical tests: Box-and-Blocks-Test, Clothespin-Relocation-Test, and Southampton-Hand-Assessment-Procedure. During all tests, upper-body kinematics has been recorded. Results: While the analysis showed that there are some correlations between the achieved clinical scores and the individual body segment travel distances and average speeds, there were only weak correlations between the clinical scores and the observed ranges of motion. At the same time, the compensations were observed in all prosthesis users and, for the most part, they were substantial across the tests. Conclusion: The sole reliance on the currently available objective clinical assessment methods seems inadequate as the compensatory movements are prominent in prosthesis users and yet not sufficiently accounted for

The long-term effects of an implantable drop foot stimulator on gait in hemiparetic patients

Drop foot is a frequent abnormality in gait after central nervous system lesions. Different treatment strategies are available to functionally restore dorsal extension during swing phase in gait. Orthoses as well as surface and implantable devices for electrical stimulation of the peroneal nerve may be used in patients who do not regain good dorsal extension. While several studies investigated the effects of implanted systems on walking speed and gait endurance, only a few studies have focussed on the system’s impact on kinematics and long-term outcomes. Therefore, our aim was to further investigate the effects of the implanted system ActiGait on gait kinematics and spatiotemporal parameters for the first time with a 1-year follow-up period. 10 patients were implanted with an ActiGait stimulator, with 8 patients completing baseline and follow-up assessments. Assessments included a 10-m walking test, video-based gait analysis and a Visual Analogue Scale (VAS) for health status. At baseline, gait analysis was performed without any assistive device as well as with surface electrical stimulation. At follow-up patients walked with the ActiGait system switched off and on. The maximum dorsal extension of the ankle at initial contact increased significantly between baseline without stimulation and follow-up with ActiGait (p = 0.018). While the spatio-temporal parameters did not seem to change much with the use of ActiGait in convenient walking speed, patients did walk faster when using surface stimulation or ActiGait compared to no stimulation at the 10-m walking test at their fastest possible walking speed. Patients rated their health better at the 1-year follow-up. In summary, a global improvement in gait kinematics compared to no stimulation was observed and the long-term safety of the device could be confirmed

The genetic versus pharmacological invalidation of the cannabinoid CB1 receptor results in differential effects on non-associative memory and forebrain monoamine concentrations in mice

Original article can be found at: http://www.sciencedirect.com/science/journal/10747427 Copyright Elsevier Inc. DOI : 10.1016/j.nlm.2007.07.013Peer reviewe

Enhanced cognitive performance and cheerful mood by standardized extracts of Piper methysticum (Kava-kava)

‘The definitive version is available at www3.interscience.wiley.com '. Copyright John Wiley & Sons, Ltd. DOI: 10.1002/hup.581 [Full text of this article is not available in the UHRA]Peer reviewe

Contralateral increase in thigmotactic scanning following unilateral cryogenic barrel-cortex lesion in mice

Original article can be found at: http://www.sciencedirect.com Copyright Elsevier [Full text of this article is not available in the UHRA]Adult C57BL/6 mice received uni- or bilateral cryogenic or sham-lesions over the barrel field and their exploratory behaviour was assessed in an open field between 1 and 7 days post-lesion. Bilateral cortical lesions produced a short-lasting increase in thigmotactic scanning with both sides of the face on the first day of testing. Mice with a unilateral barrel-cortex lesion showed more contralateral wall scanning with a recovery to behavioural symmetry after 5–7 days. Furthermore, the increase in contralateral thigmotaxis was most pronounced in animals with damage to the left barrel field, indicative of a lateralization of the lesion-induced behavioural changes. The cortical lesions did not influence locomotor activity and the rate of habituation to the open field (habituation ‘learning’). Referring to recent electrophysiological findings, we hypothesize that the lesion established a lateralized source of increased neuronal excitability within the affected barrel-cortex, leading to more behaviour with its corresponding vibrissae. Alternatively, if the lesion results in contralateral ‘neglect’ in terms of input, the increased scanning with the affected vibrissae may reflect an attempt of the system to compensate for this with an increase in usage.Peer reviewe

Repeated treatment with cholecystokinin octapeptide improves maze performance in aged Fischer 344 rats

Original article can be found at: http://www.sciencedirect.com Copyright Elsevier Inc. [Full text of this article is not available in the UHRA]Previous studies have shown that sulfated cholecystokinin octapeptide (CCK-8S) can improve learning in adult rodents when administered systemically or into the central nucleus of amygdala. Here we analyzed the effect of repeated intraperitoneal (i.p.) injection of CCK-8S on the performance of 26-month-old Fischer 344 rats in different versions of the Morris water maze and in a rota-rod test of motor coordination. Old rats were injected daily with different doses of CCK-8S (0.32 to 8.0 μg/kg; IP) 10 min before the behavioral tests. Control groups included vehicle-injected old and adult (3-month-old) F 344 rats. To control for a possible development of tolerance to the behavioral effects of repeated CCK-8S administration, groups of aged rats were included which were subjected to an acute rather than a repeated CCK injection schedule. The repeated administration of CCK-8S did not influence the performance of the old rats in the hidden-platform version of the maze. In addition, the acute treatment with CCK-8S failed to modify navigation performance in this task, suggesting that drug-tolerance may not account for the lack of behavioral effects seen after repeated CCK-8S injection. During the ‘probe trial’, the percentage of animals per group, which swam exactly across the former platform site, was markedly increased in aged rats treated repeatedly with 1.6 μg/kg CCK-8S. This might be indicative of improved retention of the prior platform location and/or a higher resistance of the learned escape response to extinction. The specificity of the effect of CCK-8S on processes related to spatial learning and memory is supported by the lack of effect on motor performance.Peer reviewe

The CB1 cannabinoid receptor antagonist AM251 blocks amphetamine-induced behavioural sensitization together with monoamine changes in the mouse nucleus accumbens and hippocampus

Original article can be found at: http://www.sciencedirect.com/ Copyright Elsevier [Full text of this article is not available in the UHRA]Endogenous cannabinoids modulate the activity of dopamine reward pathways and may play a role in the development of behavioural sensitization to psychostimulants. Here, we investigated the effects of the CB1 cannabinoid receptor antagonist AM251 on amphetamine-induced locomotor sensitization in mice. Furthermore, we measured post-mortem monoamine concentrations in nucleus accumbens and hippocampus after termination of the behavioural tests. The results can be summarized as follows: Mice pre-treated with AM251 (3 mg/kg; i.p.) showed less sensitivity to the psychomotor stimulant as well as locomotor sensitizing effects of amphetamine (2 mg/kg; i.p.) resembling previous results obtained with CB1 receptor-deficient animals. Furthermore, the behavioural effects of AM251 were paralleled by increased dopamine concentration in nucleus accumbens and increased serotonin concentration/turnover rate in hippocampus, respectively. The present data indicate that under normal conditions activation of the CB1 receptor facilitates those adaptive responses elicited by repeated psychostimulant administration and resulting in sensitization, possibly by reducing dopamine biosynthesis and serotonin turnover in the nucleus accumbens and hippocampus.Peer reviewe

Comparison of neurokinin SP with diazepam in effects on memory and fear parameters in the elevated T-maze free exploration paradigm

Original article can be found at: http://www.sciencedirect.com Copyright Elsevier Inc. [Full text of this article is not availabe in the UHRA]The elevated T-maze was combined with a free exploration protocol, which, in contrast to the conventional procedure, dispenses with handling of the animals during the experimental sessions. This allows measurement of fear indexes derived from the elevated plus-maze as well as assessment of acquisition of open arm avoidance and open arm escape in one continuous session. Retention of the different fear-responses is measured 72 h later without drug treatment. In order to assess the effects of two known anxiolytics in this paradigm, rats received an IP injection of diazepam (1 to 4 mg/kg), substance P (5 to 500 μg/kg) or vehicle (1 ml/kg) and were tested on the T-maze for 5 min. Diazepam elevated open arm activity, indicative of an anxiolytic effect. The drug also increased the latency to escape from the open arms, but did not significantly affect acquisition of open arm avoidance. During the retention trial, diazepam in higher doses impaired the performance of both fear-responses, suggestive of an anterograde amnesic effect. Substance P did not influence acquisition and retention of open arm avoidance and escape. However, in high doses, the peptide increased the sojourn time in the central arena of the maze, indicating reduced fear and, hence, a dissociation between anxiolytic and amnesic effects. The present findings demonstrate that the elevated T-maze free exploration paradigm is sensitive to anxiolytic and memory-modulating effects of drugs.Peer reviewe

Hyperanxiety produced by periaqueductal gray injection of chondroitin sulphate glycosaminoglycan

Original article can be found at: http://www.neuroreport.com Copyright Lippincott Williams & Wilkins [Full text of this article is not available in the UHRA]We examined the effects of chondroitin sulphate C (CSC) on fear and anxiety parameters following injection of the glycosaminoglycan into the dorsal periaqueductal gray. Rats with chronically implanted cannulae were administered CSC (0.4 or 4.0 nmol) or vehicle (saline, 0.2 μl) and exposed to the elevated plus-maze test of emotionality. Intra-periaqueductal gray injection of CSC produced a dose-dependent anxiogenic effect as indicated by reduced entries into and time spent on the open arms, fewer excursions into the end of the open arms and by increased stretched attend posture, flat back approach and closed arm peeping-out behaviour. The behavioural effects of CSC appeared to be anxioselective, since the glycosaminoglycan did not influence measures of general (exploratory) activity, such as number of entries into the enclosed arms and amount of scanning, rearing and grooming. The present results show that CSC can produce an anxiogenic-like profile after injection into the dorsal periaqueductal gray. This is the first such report implicating an endogenous matrix glycosaminoglycan in neural mechanisms governing fear and anxiety.Peer reviewe