Robot-assisted therapy for long-term upper-limb impairment after stroke

BACKGROUND

Effective rehabilitative therapies are needed for patients with long-term deficits after stroke.

METHODS

In this multicenter, randomized, controlled trial involving 127 patients with moderate-to-severe upper-limb impairment 6 months or more after a stroke, we randomly assigned 49 patients to receive intensive robot-assisted therapy, 50 to receive intensive comparison therapy, and 28 to receive usual care. Therapy consisted of 36 1-hour sessions over a period of 12 weeks. The primary outcome was a change in motor function, as measured on the Fugl-Meyer Assessment of Sensorimotor Recovery after Stroke, at 12 weeks. Secondary outcomes were scores on the Wolf Motor Function Test and the Stroke Impact Scale. Secondary analyses assessed the treatment effect at 36 weeks.

RESULTS

At 12 weeks, the mean Fugl-Meyer score for patients receiving robot-assisted therapy was better than that for patients receiving usual care (difference, 2.17 points; 95% confidence interval [CI], -0.23 to 4.58) and worse than that for patients receiving intensive comparison therapy (difference, -0.14 points; 95% CI, -2.94 to 2.65), but the differences were not significant. The results on the Stroke Impact Scale were significantly better for patients receiving robot-assisted therapy than for those receiving usual care (difference, 7.64 points; 95% CI, 2.03 to 13.24). No other treatment comparisons were significant at 12 weeks. Secondary analyses showed that at 36 weeks, robot-assisted therapy significantly improved the Fugl-Meyer score (difference, 2.88 points; 95% CI, 0.57 to 5.18) and the time on the Wolf Motor Function Test (difference, -8.10 seconds; 95% CI, -13.61 to -2.60) as compared with usual care but not with intensive therapy. No serious adverse events were reported.

CONCLUSIONS

In patients with long-term upper-limb deficits after stroke, robot-assisted therapy did not significantly improve motor function at 12 weeks, as compared with usual care or intensive therapy. In secondary analyses, robot-assisted therapy improved outcomes over 36 weeks as compared with usual care but not with intensive therapy. (ClinicalTrials.gov number, NCT00372411.)

Body-weight-supported treadmill rehabilitation after stroke

BACKGROUND

Locomotor training, including the use of body-weight support in treadmill stepping, is a physical therapy intervention used to improve recovery of the ability to walk after stroke. The effectiveness and appropriate timing of this intervention have not been established.

METHODS

We stratified 408 participants who had had a stroke 2 months earlier according to the extent of walking impairment--moderate (able to walk 0.4 to <0.8 m per second) or severe (able to walk <0.4 m per second)--and randomly assigned them to one of three training groups. One group received training on a treadmill with the use of body-weight support 2 months after the stroke had occurred (early locomotor training), the second group received this training 6 months after the stroke had occurred (late locomotor training), and the third group participated in an exercise program at home managed by a physical therapist 2 months after the stroke (home-exercise program). Each intervention included 36 sessions of 90 minutes each for 12 to 16 weeks. The primary outcome was the proportion of participants in each group who had an improvement in functional walking ability 1 year after the stroke.

RESULTS

At 1 year, 52.0% of all participants had increased functional walking ability. No significant differences in improvement were found between early locomotor training and home exercise (adjusted odds ratio for the primary outcome, 0.83; 95% confidence interval [CI], 0.50 to 1.39) or between late locomotor training and home exercise (adjusted odds ratio, 1.19; 95% CI, 0.72 to 1.99). All groups had similar improvements in walking speed, motor recovery, balance, functional status, and quality of life. Neither the delay in initiating the late locomotor training nor the severity of the initial impairment affected the outcome at 1 year. Ten related serious adverse events were reported (occurring in 2.2% of participants undergoing early locomotor training, 3.5% of those undergoing late locomotor training, and 1.6% of those engaging in home exercise). As compared with the home-exercise group, each of the groups receiving locomotor training had a higher frequency of dizziness or faintness during treatment (P=0.008). Among patients with severe walking impairment, multiple falls were more common in the group receiving early locomotor training than in the other two groups (P=0.02).

CONCLUSIONS

Locomotor training, including the use of body-weight support in stepping on a treadmill, was not shown to be superior to progressive exercise at home managed by a physical therapist. (Funded by the National Institute of Neurological Disorders and Stroke and the National Center for Medical Rehabilitation Research; LEAPS ClinicalTrials.gov number, NCT00243919.).

Plantarflexor weakness as a limiting factor of gait speed in stroke subjects and the compensating role of hip flexors

OBJECTIVE

To determine, using the Muscular Utilization Ratio (MUR) method, whether plantarflexor weakness is among the factors preventing stroke subjects from walking at faster speeds. Potential compensations by the hip flexors were also examined.

DESIGN

A convenience sample of 17 chronic stroke subjects in a context of a descriptive study.

BACKGROUND

Gait speed is correlated with the residual strength of the muscles involved in gait in stroke subjects. However, it has not been established if this residual strength limits gait speed.

METHODS

Kinetic and kinematic data for comfortable and maximal gait speeds were collected on the paretic side, and were used to determine the moments in plantarflexion (mechanical demand: MUR numerator) during the push-off phase. The maximal potential moment (MUR denominator) of the plantarflexors during gait was predicted using an equation derived from dynamometric data collected with a Biodex system. The MURs of the plantarflexors were then calculated at every 1% interval of the push-off phase. The pull-off phase of gait and the hip flexor strength were also examined.

RESULTS

Ten subjects of the sample had a MUR value between 80 and 150% at maximal gait speed. These subjects produced the lowest peak torques in plantarflexion. Each of the four fastest subjects of this group had a large hip flexion moment during the pull-off phase of gait and produced high hip flexion torque values on the dynamometer. Each of the seven remaining subjects had a MUR value under 70% when they walked at maximal speed.

CONCLUSIONS

Weakness of the plantarflexors should be considered as one factor limiting gait speed in 10 hemiparetic subjects. Some subjects with weak plantarflexors could walk rapidly because they compensated with the hip flexors. For the remaining stroke subjects, factors other than weakness of the plantarflexors have to be considered in order to explain the reduction in their gait speed.

Muscle strengthening and physical conditioning to reduce impairment and disability in chronic stroke survivors

OBJECTIVE

To evaluate the impact of a program of muscle strengthening and physical conditioning on impairment and disability in chronic stroke subjects.

DESIGN

A randomized pretest and posttest control group, followed by a single-group pretest and posttest design.

SUBJECTS

Thirteen community-dwelling stroke survivors of at least 9 months.

INTERVENTION

A 10-week (3 days/week) program consisting of a warm-up, aerobic exercises, lower extremity muscle strengthening, and a cool-down.

MAIN OUTCOME MEASURES

Peak isokinetic torque of the major muscle groups of the affected lower limb, quadriceps and ankle plantarflexor spasticity, gait speed, rate of stair climbing, the Human Activity Profile (HAP), and the Nottingham Health Profile (NHP) were recorded twice for the treatment group and three times for the control group.

RESULTS

Significant improvements were found for all the selected outcome measures (HAP, NHP, and gait speed) for the treatment group (p < .001). In terms of overall training effects, the 13 subjects demonstrated increases in strength of the affected major muscle groups, in HAP and NHP profiles, and in gait speed and rate of stair climbing without concomitant increases in either quadriceps or ankle plantarflexor spasticity.

CONCLUSIONS

The 10-week combined program of muscle strengthening and physical conditioning resulted in gains in all measures of impairment and disability. These gains were not associated with measurable changes of spasticity in either quadriceps or ankle plantarflexors.

Frontal and sagittal plane analyses of the stair climbing task in healthy adults aged over 40 years: what are the challenges compared to level walking?

OBJECTIVE

This study compared stair climbing and level walking in healthy adults aged over 40 years.

DESIGN

Eleven subjects performed at their comfortable speed.

BACKGROUND

The number of parameters studied during stair climbing has been limited, in particular in the frontal plane.

METHODS

Time-distance parameters and three-dimensional kinematic data were obtained using foot-switches and an Optotrak system. Ground reaction forces were collected with a force platform embedded in the second step of the staircase or in the ground for level walking. Relative angles were calculated using a Cardanic rotation matrix and the net moments and the powers at the ankle, knee and hip joints were estimated with an inverse dynamic approach.

RESULTS

A significant longer mean cycle duration and a shorter proportion of time in stance was obtained for stair climbing as compared to level walking. Profiles of the frontal plane joint angles, moments and powers indicated a different action of the hip abductors across tasks to control the pelvis in stance. Profiles of the sagittal plane confirmed the dominant role of the knee extensors during stair climbing but revealed also a knee-hip energy generation pattern that allows the avoidance of the intermediate step.

CONCLUSIONS

Results suggest environment specific adaptations of the neuro-musculo-skeletal system that should be considered in the rehabilitation of stair climbing in patients.

RELEVANCE

This study highlights the challenges of stair climbing compared to level walking in a within subject design. Key features of stair climbing that are important for the rehabilitation of step management are also reported.

Subcortical aphasia

We critically review the literature on subcortical aphasia, suggest that a number of traditional concepts regarding mechanisms of aphasia are inconsistent with now abundant data, and propose several new hypotheses. The absence of aphasia in 17 reported cases of dominant hemisphere striatocapsular infarction and the finding of nearly every conceivable pattern of language impairment in 33 different reported cases of striatocapsular infarction provide strong evidence against a major direct role of the basal ganglia in language and against disconnection or diaschisis as mechanisms of nonthalamic subcortical aphasia. However, detailed consideration of the vascular events leading to striatocapsular infarction strongly suggests that associated linguistic deficits are predominantly related to sustained cortical hypoperfusion and infarction not visible on structural imaging studies. Thalamic disconnection, as may occur with striatocapsular infarcts with extension to the temporal stem and putamenal hemorrhages, may also contribute to the language deficits in some patients. Review of the literature on thalamic infarction, in conjunction with previously unreported anatomic details of four cases, suggests that what infarcts in the tuberothalamic artery territory and the occasional infarcts in the paramedian artery territory associated with aphasia have in common is damage to the frontal lobe-inferior thalamic peduncle-nucleus reticularis-center median system that may be involved in regulating the thalamic gate in attentional processes. Disruption of attentional gating in the pulvinar and lateral posterior nuclei resulting from such lesions may impair selection of specific neuronal networks in the projection field of these nuclei that serve as the substrate for lexical-semantic function, which is in effect a disruption of a type of working memory, as defined by Goldman-Rakic. We define this as a defect of selective engagement.

How the blood talks to the brain parenchyma and the paraventricular nucleus of the hypothalamus during systemic inflammatory and infectious stimuli

There are exciting new developments regarding the molecular mechanisms involved in the influence of circulating proinflammatory molecules within cells of the blood-brain barrier (BBB) during systemic immune challenges. These molecules, when present in the circulation, have the ability to trigger a series of events in cascade, leading to either the mitogen-activated protein (MAP) kinases/nuclear factor kappa B (NF-kappaB) or the janus kinase (JAK)/signal transducer and activator of transcription (STAT) transduction pathways in vascular-associated cells of the central nervous system (CNS). The brain blood vessels exhibit both constitutive and induced expression of receptors for different proinflammatory ligands that have the ability to stimulate these signaling molecules. Depending on the challenges and the cytokines involved, the transduction signal(s) solicited in cells of the BBB may orient the neuronal activity in a very specific manner in activating the transcription and production of soluble factors, such as prostaglandins (PGs). It is interesting to note that cytokines as well as systemic localized inflammation stimulate the cells of the BBB in a nonselective manner (i.e., within both large blood vessels and small capillaries across the brain). This nonselectivity raises several questions with regard to the localized neuronal activation induced by different experimental models of inflammation and cytokines. It is possible that the selectivity of the neuronal response is a consequence of the fine interaction between nonparenchymal synthesis of soluble mediators and expression of specific receptors for these ligands within parenchymal elements of different brain nuclei. This review will present the recent developments on this concept and the mechanisms that take place in cells of the BBB, which lead to the neuronal circuits involved in restoring the body's homeostasis during systemic immunogenic challenges. The induction of fever, the hypothalamic-pituitary adrenal (HPA) axis, and other autonomic functions are among the physiological outcomes necessary for the protection of the mammalian organism in the presence of foreign material.

Creative innovation: possible brain mechanisms

This article reviews and develops some theories about the neurobiological basis of creative innovation (CI). CI is defined as the ability to understand and express novel orderly relationships. A high level of general intelligence, domain-specific knowledge and special skills are necessary components of creativity. Specialized knowledge is stored in specific portions of the temporal and parietal lobes. Some anatomic studies suggest that talented people might have alterations of specific regions of the posterior neocortical architecture, but further systematic studies are needed. Intelligence, knowledge and special skills, however, are not sufficient for CI. Developing alternative solutions or divergent thinking has been posited to be a critical element of CI, and clinical as well as functional imaging studies suggest that the frontal lobes are important for these activities. The frontal lobes have strong connections with the polymodal and supramodal regions of the temporal and parietal lobes where concepts and knowledge are stored. These connections might selectively inhibit and activate portions of posterior neocortex and thus be important for developing alternative solutions. Although extensive knowledge and divergent thinking together are critical for creativity they alone are insufficient for allowing a person to find the thread that unites. Finding this thread might require the binding of different forms of knowledge, stored in separate cortical modules that have not been previously associated. Thus, CI might require the co-activation and communication between regions of the brain that ordinarily are not strongly connected. The observations that CI often occurs during levels of low arousal and that many people with depression are creative suggests that alterations of neurotransmitters such as norepinephrine might be important in CI. High levels of norepinephrine, produced by high rates of locus coeruleus firing, restrict the breadth of concept representations and increase the signal to noise ratio, but low levels of norepinephrine shift the brain toward intrinsic neuronal activation with an increase in the size of distributed concept representations and co-activation across modular networks. In addition to being important in divergent thinking, the frontal lobes are also the primary cortical region that controls the locus coeruleus-norepinephrine system. Thus creative people may be endowed with brains that are capable of storing extensive specialized knowledge in their temporoparietal cortex, be capable of frontal mediated divergent thinking and have a special ability to modulate the frontal lobe-locus coeruleus (norepinephrine) system, such that during creative innovation cerebral levels of norepinephrine diminish, leading to the discovery of novel orderly relationships.

Effects of circulating tumor necrosis factor on the neuronal activity and expression of the genes encoding the tumor necrosis factor receptors (p55 and p75) in the rat brain: a view from the blood-brain barrier

Tumor necrosis factor is a potent activator of myeloid cells, which acts via two cell-surface receptors, the p55 and p75 tumor necrosis factor receptors. The present study describes the cellular distribution of both receptor messenger RNAs across the rat brain under basal conditions and in response to systemic injection with the bacterial endotoxin lipopolysaccharide and recombinant rat tumor necrosis factor-alpha. Time-related induction of the messenger RNA encoding c-fos, cyclo-oxygenase-2 enzyme and the inhibitory factor kappa B alpha was assayed as an index of activated neurons and cells of the microvasculature by intravenous tumor necrosis factor-alpha challenge. The effect of the proinflammatory cytokine on the hypothalamic-pituitary-adrenal axis was determined by measuring the transcriptional activity of corticotropin-releasing factor and plasma corticosterone levels. Constitutive expression of p55 messenger RNA was detected in the circumventricular organs, choroid plexus, leptomeninges, the ependymal lining cells of the ventricular walls and along the blood vessels, whereas p75 transcript was barely detectable in the brain under basal conditions. Immunogenic insults caused up-regulation of both tumor necrosis factor receptors in barrier-associated structures, as well as over the blood vessels, an event that was associated with a robust activation of the microvasculature. Indeed, intravenous tumor necrosis factor-alpha provoked a rapid and transient transcription of inhibitory factor kappa B alpha and cyclo-oxygenase-2 within cells of the blood-brain barrier, and a dual-labeling technique provided the anatomical evidence that the endothelium of the brain capillaries expressed inhibitory factor kappa B alpha. Circulating tumor necrosis factor-alpha also rapidly stimulated c-fos expression in nuclei involved in the autonomic control, including the bed nucleus of the stria terminalis, the paraventricular nucleus of the hypothalamus, the central nucleus of the amygdala, the nucleus of the solitary tract and the ventrolateral medulla. A delayed c-fos mRNA induction was detected in the circumventricular organs, organum vascularis of the lamina terminalis, the subfornical organ, the median eminence and the area postrema. The paraventricular nucleus of the hypothalamus exhibited expression of corticotropin-releasing factor primary transcript that was associated with a sharp increase in the plasma corticosterone levels 1h after intravenous tumor necrosis factor-alpha administration. Taken together, these data provide the evidence that p55 is the most abundant tumor necrosis factor receptor in the central nervous system and is expressed in barrier-associated structures. Circulating tumor necrosis factor has the ability to directly activate the endothelium of the brain's large blood vessels and small capillaries, which may produce soluble molecules (such as prostaglandins) to vehicle the signal through parenchymal elements. The pattern of c-fos-inducible nuclei suggests complex neuronal circuits solicited by the cytokine to activate neuroendocrine corticotropin-releasing factor and the corticotroph axis, a key physiological response for the appropriate control of the systemic inflammatory response.

Analysis of the clinical factors determining natural and maximal gait speeds in adults with a stroke

The objective of this study was to identify the most important clinical variables determining gait speed in persons with stroke. Sixteen chronic stroke subjects (mean age, 47.9 (+/-15.6) yr; mean time post-stroke, 43.9 (+/-36.5) mo) able to walk independently without a brace participated in the study. The impairments in motor function, sensation of the paretic lower limb, and balance were evaluated with the Fugl-Meyer Assessment. A spasticity index was used to assess the muscle tone of the plantarflexors. The maximal strengths in plantarflexion and hip flexion were measured with a Biodex dynamometric system. Cinematography and foot-contact data collected on the paretic side were used to determine the comfortable and maximal gait speeds. The level of association between gait speeds and the clinical variables were first examined with Pearson's correlation coefficients and, then, with multiple linear regression analyses using the stepwise method. Results revealed that the motor function of the lower limb, balance, and hip flexion strength were significantly related to comfortable and maximal gait speeds (0.5 < r < 0.88; P < 0.05). For the comfortable gait speed, the regression analysis selected only the hip flexor strength as a significant variable (R2 = 0.69). For maximal gait speed, the variables retained were hip flexor strength, sensation at the lower limb, and plantarflexor strength (R2 = 0.85). The present results suggest that strength and sensation at the lower limb are important factors to consider in determining the gait capacity of chronic stroke subjects.

A possible pathophysiologic substrate of attention deficit hyperactivity disorder

The attention deficit hyperactivity disorder (ADHD) is associated with defective attention and response inhibition and motor restlessness. Inattention, defective response inhibition, and impersistence are more commonly seen in adults with right than with left hemisphere dysfunction. In light of this fact and because children with ADHD not only appear to demonstrate these symptoms but also neglect the left side and have decreased activation of their right neostriatum, we propose that these children have a right hemisphere dysfunction. In addition, because both inattention and defective response inhibition can be seen in children with ADHD and in patients and animals who have frontal lobe and striatal dysfunction, we propose that children with ADHD have dysfunction in a right-sided frontal-striatal system. Motor restlessness may reflect frontal lobe dysfunction due to impairment of the mesocortical dopamine system.

Protocol for the Locomotor Experience Applied Post-stroke (LEAPS) trial: a randomized controlled trial

BACKGROUND

Locomotor training using body weight support and a treadmill as a therapeutic modality for rehabilitation of walking post-stroke is being rapidly adopted into clinical practice. There is an urgent need for a well-designed trial to determine the effectiveness of this intervention. The objective of the Locomotor Experience Applied Post-Stroke (LEAPS) trial is to determine if there is a difference in the proportion of participants who recover walking ability at one year post-stroke when randomized to a specialized locomotor training program (LTP), conducted at 2- or 6-months post-stroke, or those randomized to a home based non-specific, low intensity exercise intervention (HEP) provided 2 months post-stroke. We will determine if the timing of LTP delivery affects gait speed at 1 year and whether initial impairment severity interacts with the timing of LTP. The effect of number of treatment sessions will be determined by changes in gait speed taken pre-treatment and post-12, -24, and -36 sessions.

METHODS/DESIGN

We will recruit 400 adults with moderate or severe walking limitations within 30 days of stroke onset. At two months post stroke, participants are stratified by locomotor impairment severity as determined by overground walking speed and randomly assigned to one of three groups: (a) LTP-Early; (b) LTP-Late or (c) Home Exercise Program -Early. The LTP program includes body weight support on a treadmill and overground training. The LTP and HEP interventions are delivered for 36 sessions over 12 weeks. Primary outcome measure include successful walking recovery defined as the achievement of a 0.4 m/s gait speed or greater by persons with initial severe gait impairment or the achievement of a 0.8 m/s gait speed or greater by persons with initial moderate gait impairment.LEAPS is powered to detect a 20% difference in the proportion of participants achieving successful locomotor recovery between the LTP groups and the HEP group, and a 0.1 m/s mean difference in gait speed change between the two LTP groups.

DISCUSSION

The goal of this single-blinded, phase III randomized clinical trial is to provide evidence to guide post-stroke walking recovery programs.

TRIAL REGISTRATION

NCT00243919.

Repetitive transcranial magnetic stimulation as an adjunct to constraint-induced therapy: an exploratory randomized controlled trial

OBJECTIVE

To test the potential adjuvant effect of repetitive transcranial magnetic stimulation (rTMS) on motor learning in a group of stroke survivors undergoing constraint-induced therapy (CIT) for upper-limb hemiparesis.

DESIGN

This was a prospective randomized, double-blind, sham-controlled, parallel group study. Nineteen individuals, one or more years poststroke, were randomized to either a rTMS + CIT (n = 9) or a sham rTMS + CIT (n = 10) group and participated in the 2-wk intervention.

RESULTS

Regardless of group assignment, participants demonstrated significant gains on the primary outcome measures: the Wolf Motor Function Test (WMFT) and the Motor Activity Log (MAL)--Amount of Use, and on secondary outcome measures including the Box and Block Test (BBT) and the MAL--How Well. Participants receiving rTMS failed to show differential improvement on either primary outcome measure.

CONCLUSIONS

Although this study provided further evidence that even relatively brief sessions of CIT can have a substantial effect, it provided no support for adjuvant use of rTMS.

Conduction aphasia and the arcuate fasciculus: A reexamination of the Wernicke-Geschwind model

Wernicke, and later Geschwind, posited that the critical lesion in conduction aphasia is in the dominant hemisphere's arcuate fasciculus. This white matter pathway was thought to connect the anterior language production areas with the posterior language areas that contain auditory memories of words (a phonological lexicon). Alternatively, conduction aphasia might be induced by cortical dysfunction, which impairs the phonological output lexicon. We observed an epileptic patient who, during cortical stimulation of her posterior superior temporal gyrus, demonstrated frequent phonemic paraphasias, decreased repetition of words, and yet had intact semantic knowledge, a pattern consistent with conduction aphasia. These findings suggest that cortical dysfunction alone may induce conduction aphasia.

Effects of muscle strengthening and physical conditioning training on temporal, kinematic and kinetic variables during gait in chronic stroke survivors

The purpose of this study was to evaluate the impact of a combined program of muscle strengthening and physical conditioning on gait performance in subjects with chronic stroke, using a single group pre- and post-test design. Thirteen subjects were recruited for the 10-week program (3 days/week), which consisted of warm-up, aerobic exercises, lower extremity muscle strengthening and cool-down. Data from cinematographic film and a force plate obtained during multiple walking trials were used in a four-segment kinetic model to yield spatiotemporal, kinematic and kinetic variables. Gait analysis revealed that the 10 week training resulted in significant increases in gait speed associated with improvements in walking patterns as determined by increases in selected kinematic and kinetic measures. After training, subjects were able to generate higher levels of powers and demonstrated increases in positive work performed by the ankle plantar flexor and hip flexor/extensor muscles.

Regulation of the gene encoding tumor necrosis factor alpha (TNF-alpha) in the rat brain and pituitary in response in different models of systemic immune challenge

Tumor necrosis factor (TNF)-alpha is usually referred to as a proinflammatory cytokine that plays a central role in initiating the cascade of other cytokines and factors for an appropriate immune response to infection. Like systemic phagocytes, recent studies have reported that specific cellular populations of the CNS have the ability to express and release the proinflammatory cytokine in response to peripheral administration of the bacterial endotoxin lipopolysaccharide (LPS). Whether such phenomenon represents a general mechanism of systemic immunogenic stimuli and how the severity of the challenge may influence TNF-alpha transcription in the brain has yet to be defined. Adult male rats were sacrificed 1, 3, 6, 12, 24 and 48 hours (h) after intraperitoneal (IP) injection of LPS (25-250 microg/100 g) or intramuscular (IM) injection of turpentine. Brains and pituitary glands were removed, cut, and TNF-alpha mRNA assayed by in situ hybridization using a full-length rat cRNA probe. The results show no positive signal under basal conditions or following sterile inflammation into the left hind limb. Systemic LPS caused a profound increase in the expression of the gene encoding TNF-alpha in the leptomeninges, choroid plexus (chp) and all sensorial circumventricular organs (CVOs). Interestingly, a migratory-like pattern of TNF-alpha-positive cells became apparent around the sensorial CVOs at 3 h, while a ubiquitous-like positive signal was found throughout the brain 6 h after the injection with the highest dose of LPS. The IP LPS injection also stimulated TNF-alpha transcription in the anterior pituitary lobe; the signal was maximal 1 h after the injection and returned gradually to basal levels at 12 h, whereas the mRNA encoding the cytokine was detected later in the neurohypophysis, i.e. 3 and 6 h post challenge. Dual-labeling procedure provided the evidence of an LPS-dependent induction of TNF-alpha in different phagocytic cellular populations of the brain, including parenchymal microglial cells during severe endotoxemia. The fact that these myeloid-derived cells have the ability to express the LPS receptor CD14 in the brain may well explain the transcriptional activation of the cytokine in response to the bacterial endotoxin, but not to systemic localized inflammation.

Effects of left frontal transcranial magnetic stimulation on depressed mood, cognition, and corticomotor threshold

BACKGROUND

The pathophysiology of depression may include synaptic hypoactivity of left prefrontal cortex. Several groups of investigators have described improved mood associated with rapid transcranial magnetic stimulation (rTMS) but have not looked for possible cognitive side effects associated with left prefrontal magnetic stimulation.

METHODS

We measured the effects of left prefrontal rTMS on mood, cognition, and motor evoked potential threshold in 10 patients with medication-resistant major depression.

RESULTS

In a 2-week open trial of left prefrontal rTMS off antidepressant medications, scores on the Hamilton Rating Scale for Depression and the Beck Depression Inventory decreased by 41% and 40%, respectively. After resuming pre-rTMS antidepressant medication, improvement in mood was still significant at 1 and 3 months later. rTMS had no adverse effects on neuropsychological performance. rTMS treatments were associated with significant decreases in motor evoked potential threshold in the 9 of 10 patients who remained off psychotropic medications during the 2-week treatment period.

CONCLUSIONS

These preliminary data suggest that left prefrontal rTMS is safe and improves mood in patients with medication-resistant major depression. Changes in motor evoked potential threshold suggest that prefrontal rTMS may alter brain activity at sites remote from the stimulation. Double-blind, sham-controlled studies are needed.

Standing balance assessment in ASIA D paraplegic and tetraplegic participants: concurrent validity of the Berg Balance Scale

STUDY DESIGNS

Longitudinal and correlational study with repeated measures.

OBJECTIVES

The aim of this study was to test the concurrent validity of the Berg Balance Scale (BBS) for a spinal cord injury (SCI) population.

PARTICIPANTS

A total of 32 individuals with an ASIA D SCI walking 10 m independently, with or without walking assistive devices.

SETTING

An intensive rehabilitation center in Montréal, Canada.

METHODS

Subjects were evaluated on the BBS, the Walking Index for Spinal Cord Injury (WISCI II), the Spinal Cord Injury Functional Ambulation Inventory (SCI-FAI), the 10-m walk test (10MWT) and the Timed Up and Go (TUG). Individuals were reassessed during rehabilitation when progressing to a device providing less support or to unassisted gait.

RESULTS

All walking tests were highly correlated with the BBS (0.714<Rs<0.816, P<or=0.01). A significant ceiling effect was found on the BBS, the WISCI and on most subsections of the SCI-FAI. Assistive devices used for walking relate well to the BBS score (Spearman's rho 0.714, P<0.01).

CONCLUSION

The BBS is an appropriate assessment of standing balance for individuals with SCI. Complementary evaluation with the 10MWT or the 2MWT is recommended to supplement the ceiling effect on the BBS.

Effect of Verb Network Strengthening Treatment (VNeST) on Lexical Retrieval of Content Words in Sentences in Persons with Aphasia

BACKGROUND: Verb Network Strengthening Treatment (VNeST) is a semantic treatment that aims to improve lexical retrieval of content words in sentence context by promoting systematic retrieval of verbs (e.g., measure) and their thematic roles (i.e., agent (doer of the action, e.g., carpenter, chef)) and patient (receiver of the action, e.g., lumber, sugar)). VNeST is influenced by Loverso and colleagues (e.g., Loverso, Selinger, and Prescott, 1979), who used "verb as core" treatment to improve sentence production with encouraging results, and McRae and colleagues, who showed that verbs prime typical agents (e.g., pray-nun) and patients (arrest-criminal) (Ferretti, McRae, & Hatherell, 2001) and vice-versa (McRae, Hare, Elman, & Ferretti, 2005). AIMS: There are four specific questions in this study. Does training a set of verbs using VNeST generalize to the ability to produce 1) an agent (carpenter), trained verb (measure), and patient (stairs) in response to novel picture stimuli and 2) an agent (nurse), untrained semantically related verb (weigh), and patient (baby) in response to novel picture stimuli? 3) Are generalization effects maintained?, and 4) Does VNeST generalize to the ability to retrieve nouns and verbs not directly related to treatment items in single word naming, picture description and connected speech tasks? METHODS #ENTITYSTARTX00026; PROCEDURES: Four participants with aphasia participated. Participants received VNeST, which involves retrieval of agent-patient pairs (e.g., chef/sugar, surveyor/land) related to trained verbs (e.g., measure), two times per week. A single subject, repeated probe, multiple baseline experimental design was used. Generalization to sentence production for sentences containing trained verbs and untrained semantically related verbs was tested weekly. OUTCOMES #ENTITYSTARTX00026; RESULTS: Results demonstrated generalization to lexical retrieval of content words in sentences with trained and untrained verbs across participants. Additionally, pre- to post-treatment generalization was observed on single verb and noun naming and lexical retrieval in sentences across a variety of tasks across participants. Generalization to connected speech was observed for 3 of 4 participants. CONCLUSIONS: Though preliminary, these results indicate that VNeST may be effective in promoting generalization from single word naming to connected speech in persons with moderate aphasia. A number of clinical implications related to treatment efficiency are discussed.

Droperidol lengthens cardiac repolarization due to block of the rapid component of the delayed rectifier potassium current

INTRODUCTION

Torsades de pointes have been observed during treatment with droperidol, a butyrophenone neuroleptic agent. Our objectives were (1) to characterize the effects of droperidol on cardiac repolarization and (2) to evaluate effects of droperidol on a major time-dependent outward potassium current involved in cardiac repolarization (I(K)r).

METHODS AND RESULTS

Isolated, buffer-perfused guinea pig hearts (n = 32) were stimulated at different pacing cycle lengths (150 to 250 msec) and exposed to droperidol in concentrations ranging from 10 to 300 nmol/L. Droperidol increased monophasic action potential duration measured at 90% repolarization (MAPD90) in a concentration-dependent manner by 9.8+/-2.3 msec (7.3%+/-0.7%) at 10 nmol/L but by 32.7+/-3.6 msec (25.7%+/-2.2%) at 300 nmol/L (250-msec cycle length). Increase in MAPD90 also was reverse frequency dependent. As noted previously, droperidol 300 nmol/L increased MAPD90 by 32.7+/-3.6 msec (25.7%+/-2.2%) at a pacing cycle length of 250 msec but by only 14.1+/-1.3 msec (13.6%+/-2.3%) at a pacing cycle length of 150 msec. Patch clamp experiments performed in isolated guinea pig ventricular myocytes demonstrated that droperidol decreases the time-dependent outward K+ current elicited by short depolarizations (250 msec; I(K)250) in a concentration-dependent manner. Estimated IC50 for I(K)250, which mostly underlies I(K)r, was 28 nmol/L. Finally, HERG K+ current elicited in HEK293 cells expressing high levels of HERG protein was decreased 50% by droperidol 32.2 nmol/L.

CONCLUSION

Potent block of I(K)r by droperidol is likely to underlie QT prolongation observed in patients treated at therapeutic plasma concentrations (10 to 400 nmol/L) of the drug.

Pupil sparing in oculomotor palsy: a brief review

The clinical dictum that pupil sparing in oculomotor nerve palsy predicts an extraaxial ischemic lesion while pupil involvement predicts an extraaxial compressive lesion has some important exceptions. Two case reports and a review of the literature disclose that pupil sparing occurs in a small proportion of intraaxial and compressive subarachnoid oculomotor nerve lesions and in a large proportion of compressive cavernous sinus oculomotor nerve lesions. Careful examination is also necessary to separate examples of apparent pupil sparing in cases of aberrant regeneration and in some instances of cavernous sinus compression.

Increased discrimination of "false memories" in autism spectrum disorder

Individuals with autism spectrum disorder (ASD) have impaired ability to use context, which may manifest as alterations of relatedness within the semantic network. However, impairment in context use may be more difficult to detect in high-functioning adults with ASD. To test context use in this population, we examined the influence of context on memory by using the "false memory" test. In the false memory task, lists of words were presented to high-functioning subjects with ASD and matched controls. Each list consists of words highly related to an index word not on the list. Subjects are then given a recognition test. Positive responses to the index words represent false memories. We found that individuals with ASD are able to discriminate false memory items from true items significantly better than are control subjects. Memory in patients with ASD may be more accurate than in normal individuals under certain conditions. These results also suggest that semantic representations comprise a less distributed network in high-functioning adults with ASD. Furthermore, these results may be related to the unusually high memory capacities found in some individuals with ASD. Research directed at defining the range of tasks performed superiorly by high-functioning individuals with ASD will be important for optimal vocational rehabilitation.

Effects of Task-Specific and Impairment-Based Training Compared With Usual Care on Functional Walking Ability After Inpatient Stroke Rehabilitation

Background. After inpatient stroke rehabilitation, many people still cannot participate in community activities because of limited walking ability. Objective. To compare the effectiveness of 2 conceptually different, early physical therapy (PT) interventions to usual care (UC) in improving walking 6 months after stroke. Methods. The Locomotor Experience Applied Post-Stroke (LEAPS) study was a single-blind, randomized controlled trial conducted in 408 adults with disabling hemiparetic stroke. Participants were stratified at baseline (2 months) by impairment in walking speed: severe (<0.4 m/s) or moderate (0.4 to <0.8 m/s). Between 2 and 6 months, they received either only UC (n = 143) or UC plus 36 therapist-provided sessions of either (1) walking training on a treadmill using body-weight support and practice overground at clinics (locomotor training program [LTP], n = 139) or (2) impairment-based strength and balance exercise at home (home exercise program [HEP], n = 126). Results. LTP participants were 18% more likely to transition to a higher functional walking level: severe to >0.4 m/s and moderate to >0.8 m/s than UC participants (95% confidence interval [CI] = 7%-29%), and HEP participants were 17% more likely to transition (95% CI = 5%-29%). Mean gain in walking speed in LTP participants was 0.13 m/s greater (95% CI = 0.09-0.18) and in HEP participants, 0.10 m/s greater (95% CI = 0.05-0.14) than in UC participants. Conclusions. Progressive PT, using either walking training on a treadmill and overground, conducted in a clinic, or strength and balance exercises conducted at home, was superior to UC in improving walking, regardless of severity of initial impairment.

Category-specific naming deficits for objects and actions: semantic attribute and grammatical role hypotheses

Research on category-specific naming deficits and on noun and verb naming has raised questions about how organization of knowledge in the brain impacts word retrieval. The semantic attribute hypothesis posits that lexical access is mediated by brain systems that process the most definitive attributes of specific concepts. For example, it has been suggested that the most definitive attribute of living things is their visual form, whereas the most definitive attribute of non-living things is their function. The competing grammatical role hypothesis posits that access to a word depends on the grammatical role it plays in a sentence. Since nouns and verbs have different roles, it is assumed that the brain uses different systems to process them. These two hypotheses were tested in experimental subjects who had undergone left anterior temporal lobectomy (LATL) or right anterior temporal lobectomy (RATL) by assessing confrontation naming of living things, tools/implements, non-human actions, and human actions. The names of living things and implements are nouns and the names of actions are verbs. Within each grammatical class, items were characterized either predominantly by visual attributes (living things and non-human actions) or by attributes related to human activity (implements and human actions). Our results support the semantic attribute hypothesis. Patients with LATL were worse at naming tools/implements and human actions than RATL patients. Dysfunction in or removal of the left anterior temporal lobe disrupts fronto-temporal connections from the uncinate fasciculus. These connections may mediate activation of action-related information (i.e. movement plan and/or motor use) that facilitates the retrieval of names for tools/implements and human actions.

Moral distress in the neonatal intensive care unit: caregiver's experience

BACKGROUND

The Neonatal Intensive Care Unit (NICU) can be ethically charged, which can create challenges for health-care workers.

OBJECTIVE

To determine the frequency with which nurses and residents have experienced ethical confrontations and what factors are associated with increased frequency.

DESIGN/METHODS

An anonymous questionnaire was distributed to nurses in a university center, a high-risk obstetric service, a maternity hospital NICU with 85% in-born patients and an outborn NICU, most of whose preterm admissions are those with surgical complications. Obstetric and pediatric residents in the four universities of the province also received the questionnaire, which included demographics, opinions regarding the gestational age threshold at which resuscitation of a premature infant with bradycardia was appropriate, knowledge of cerebral palsy (CP) outcomes (as an indicator of knowledge about long-term sequelae of prematurity) and questions about ethical confrontation in the NICU.

RESULTS

Two hundred and seventy-nine caregivers participated (115 full time nurses and 164 residents). All the distributed questionnaires were completed. Frequent ethical confrontation was reported by 35% of the nurses and 19% of the residents. Among the nurses, moral distress differed significantly between work environments. Nurses working in an out-born NICU and obstetric nurses were more likely to overestimate CP prevalence (P<0.05). Nurses who overestimated CP rates had higher thresholds for resuscitation and were more likely to experience ethical confrontations. Of the residents, 60% were pediatric and 40% obstetric. All groups of residents frequently overestimated the prevalence of CP, and knowledge differed significantly by residency program (P<0.05). The residents who overestimated CP rates had higher thresholds for resuscitation, had more incorrect answers regarding prematurity outcomes and were less likely to have ethical confrontations.

CONCLUSIONS

A large proportion of nurses and residents report frequent ethical confrontations. Many residents and nurses have limited knowledge of outcomes and high threshold for resuscitation. Ethical confrontation is more common among nurses with poor knowledge about outcomes, and less common in residents with poor knowledge about outcomes.