Influence of posture on blink reflex prepulse inhibition induced by somatosensory inputs from upper and lower limbs.

BACKGROUND: Prepulse inhibition (PPI) is a neurophysiological phenomenon whereby a weak stimulus modulates the reflex response to a subsequent strong stimulus. Its physiological purpose is to avoid interruption of sensory processing by subsequent disturbing stimuli at the subcortical level, thereby preventing undesired motor reactions. An important hub in the PPI circuit is the pedunculopontine nucleus, which is also involved in the control of posture and sleep/wakefulness. OBJECTIVE: To study the effect of posture (supine versus standing) on PPI, induced by somatosensory prepulses to either upper or lower limb. PPI was measured as the percentage inhibition of the blink reflex response to electrical supraorbital nerve (SON) stimulation. METHODS: Sixteen healthy volunteers underwent bilateral blink reflex recordings following SON stimulation either alone (baseline) or preceded by an electrical prepulse to the median nerve (MN) or sural nerve (SN), both in supine and standing. Stimulus intensity was 8 times sensory threshold for SON, and 2 times sensory threshold for MN and SN, respectively. Eight stimuli were applied in each condition. RESULTS: Baseline blink reflex parameters did not differ significantly between the two postures. Prepulse stimulation to MN and SN caused significant inhibition of R2. In supine but not in standing, R2 was significantly more inhibited by MN than by SN prepulses. In standing, SN stimulation caused significantly more inhibition of R2 than in supine, while the inhibition caused by MN prepulses did not differ significantly between postures. SIGNIFICANCE: PPI induced by lower limb afferent input may contribute to postural control while standing.

Transcranial magnetic stimulation studies in complex regional pain syndrome type I: A review.

The sensory and motor cortical representation corresponding to the affected limb is altered in patients with complex regional pain syndrome (CRPS). Transcranial magnetic stimulation (TMS) represents a useful non-invasive approach for studying cortical physiology. If delivered repetitively, TMS can also modulate cortical excitability and induce long-lasting neuroplastic changes. In this review, we performed a systematic search of all studies using TMS to explore cortical excitability/plasticity and repetitive TMS (rTMS) for the treatment of CRPS. Literature searches were conducted using PubMed and EMBASE. We identified 8 articles matching the inclusion criteria. One hundred fourteen patients (76 females and 38 males) were included in these studies. Most of them have applied TMS in order to physiologically characterize CRPS type I. Changes in motor cortex excitability and brain mapping have been reported in CRPS-I patients. Sensory and motor hyperexcitability are in the most studies bilateral and likely involve corresponding regions within the central nervous system rather than the entire hemisphere. Conversely, sensorimotor integration and plasticity were found to be normal in CRPS-I. TMS examinations also revealed that the nature of motor dysfunction in CRPS-I patients differs from that observed in patients with functional movement disorders, limb immobilization, or idiopathic dystonia. TMS studies may thus lead to the implementation of correct rehabilitation strategies in CRPS-I patients. Two studies have begun to therapeutically use rTMS. This non-invasive brain stimulation technique could have therapeutic utility in CRPS, but further well-designed studies are needed to corroborate initial findings.

Low-frequency rTMS of the unaffected hemisphere in stroke patients: A systematic review.

The aim of this review was to summarize the evidence for the effectiveness of low-frequency (LF) repetitive transcranial magnetic stimulation (rTMS) over the unaffected hemisphere in promoting functional recovery after stroke. We performed a systematic search of the studies using LF-rTMS over the contralesional hemisphere in stroke patients and reviewed the 67 identified articles. The studies have been gathered together according to the time interval that had elapsed between the stroke onset and the beginning of the rTMS treatment. Inhibitory rTMS of the contralesional hemisphere can induce beneficial effects on stroke patients with motor impairment, spasticity, aphasia, hemispatial neglect and dysphagia, but the therapeutic clinical significance is unclear. We observed considerable heterogeneity across studies in the stimulation protocols. The use of different patient populations, regardless of lesion site and stroke aetiology, different stimulation parameters and outcome measures means that the studies are not readily comparable, and estimating real effectiveness or reproducibility is very difficult. It seems that careful experimental design is needed and it should consider patient selection aspects, rTMS parameters and clinical assessment tools. Consecutive sessions of rTMS, as well as the combination with conventional rehabilitation therapy, may increase the magnitude and duration of the beneficial effects. In an increasing number of studies, the patients have been enrolled early after stroke. The prolonged follow-up in these patients suggests that the effects of contralesional LF-rTMS can be long-lasting. However, physiological evidence indicating increased synaptic plasticity, and thus, a more favourable outcome, in the early enrolled patients, is still lacking. Carefully designed clinical trials designed are required to address this question. LF rTMS over unaffected hemisphere may have therapeutic utility, but the evidence is still preliminary and the findings need to be confirmed in further randomized controlled trials.

[ARMOR: an electromechanical robot for upper limb training following stroke. A prospective randomised controlled pilot study]. / ARMOR: Elektromechanischer Roboter für das Bewegungstraining der oberen Extremität nach Schlaganfall. Prospektive randomisierte kontrollierte Pilotstudie.

PURPOSE: Due to the complexity of the upper motor neuron syndrome, functional improvement in the paretic upper limb after stroke continues to be a challenge in neurorehabilitation. Robot-assisted training has been shown to be useful in relearning gait. In order to achieve similar results in the upper limb, an electromechanical arm robot (ARMOR), capable of moving all joints through complex patterns, has been developed. MATERIAL AND METHOD: Eight patients following stroke of different etiologies were included in a clinical AB-BA cross-over study comparing ARMOR training with EMG-triggered neuromuscular electrical stimulation (EMG-NMES). Chedoke-McMaster Stroke Assessment, modified Ashworth Scale, goniometry (Neutral-0-Method), dynamometry and Functional Dexterity Test served as outcome measures. RESULTS: ARMOR training resulted in more improvement of muscle tone (p = 0.004), range of movement (ROM) (p = 0.005) and dexterity, but less improvement of strength, than EMG-NMES. Chedoke-McMaster Stroke Assessment showed improvement of at least one point in shoulder pain and arm and hand activity during ARMOR training, while these values did not change with EMG-NMS. Better results of ARMOR training were achieved in the earlier phase (A1) than in the later phase (A2). CONCLUSION: This study demonstrates the positive effect of automatised training with a new electromechanical arm robot (ARMOR), and documents its clinical applicability in the rehabilitation of the paretic upper extremity in stroke patients.

Intrathecal baclofen therapy for spasticity of cerebral origin: cerebral palsy and brain injury.

Spasticity affects approximately 66% of individuals with cerebral palsy and 14% of the 100,000 individuals who, each year, experience brain injury in the US. This spasticity interferes with motor function and limits range of motion. It may cause pain and impede mobility, transfers, activities of daily living, sitting posture, and sleep. In addition, spasticity can contribute to the formation of pressure sores and joint contractures and make nursing or caregiving difficult. Several treatment options are available for intractable spasticity. For some diagnoses, oral medications are still the treatment of choice, while in other settings injection therapy may be more appropriate. If, however, they are ineffective or cause too many side effects, intrathecal baclofen therapy (ITB) may be a valuable alternative. ITB is effective, nondestructive, titratable, and reversible. In addition, it is associated with fewer CNS-related side effects than oral Lioresal (Novartis Pharma AG, Basel, Switzerland). Intrathecal baclofen therapy may improve range of motion, facilitate movement, reduce the patient's expenditure of energy, facilitate nursing, reduce the risk of developing contractures, and, in some cases, diminish pain resulting from spasticity and/or spasms. It also may improve speech, gait, upper extremity function, and activities of daily living, including communication, eating, dressing, hygiene, and other aspects of self-care. A recent study shows that treatment with intrathecal baclofen reduces the need for corrective orthopedic surgeries. Patient selection should be done in a multidisciplinary spasticity setting, where the expertise for different treatment modalities is available. Patients must be screened for response to the drug prior to implantation of the drug delivery pump. Maintenance doses for intrathecal baclofen range from 22 to 1400 µg/day, with most patients adequately maintained on 90-703 µg/day. Complications, while rare, are most often related to the drug delivery catheter. Intrathecal baclofen treatment may be cost effective, primarily due to a reduced need for hospitalizations and treatment of adverse events related to uncontrolled spasticity, and may improve quality of life. Intrathecal baclofen shows long-term efficacy in both higher and lower level patients with cerebral origin spasticity.

Epileptic seizure associated with intracerebroventricular and intrathecal morphine bolus.

We report on two patients with morphine-related seizures associated with either intrathecal or intracerebroventricular administration. Both patients had a history of malignant tumor and both experienced the seizures following bolus application of morphine, while even higher dosages were well tolerated when continuously infused. Seizures occurred without signs of intoxication. Initiation of intrathecal morphine therapy and bolus application should be performed carefully and only when constant monitoring is provided for at least 12 h. Animal data and possible mechanisms for morphine-related seizures are discussed.

[Care of stroke patients by relatives--social support and coping strategies]. / Pflege von Schlaganfallpatienten durch Angehörige--soziale Unterstützung und Bewältigungsstrategien.

OBJECTIVE: To assess the coping ability and the social support of relatives looking after patients who have had a stroke. Of special interest was to ascertain how coping behaviour and social support differed between short-term (caring period of 3-6 months) and long-term (caring period longer than 2 years) carers. Differences in social networking between relatives and a control group (no caring tasks) were also assessed. SUBJECTS AND METHODS: A questionnaire based on the well-established "Berne coping forms" and another on social support were filled in by 20 relatives (18 women, two men; mean age 50.6 years) after a short-term caring period of up to 6 months and 20 relatives after a caring period longer than 2 years (14 women, six men; mean age 64.9 years) and a control group (27 women, 10 men; mean age 57.8 years). RESULTS: Among the total group of relatives the coping strategies (listed by order of importance) were: "passive cooperation", "acceptance", and "lending a hand". The short- and long-term carers showed no significant differences in these strategies. However, there were significant deficits in social support between the relatives and the controls as to practical support (P < 0.05), social integration (P < 0.01), social support received (P < 0.01), social burden (P < 0.01) and the caring persons (P < 0.05). There was no difference regarding social support between the short- and long-term carers. CONCLUSIONS: The results confirm the importance of social support for relatives who look after stroke patients. Every form of psychosocial help should be given at the time the patient is discharged to home care. This would require day clinics and short-term places in nursing homes.

The impact of jejunal transplant peristalsis on enteric flora.

The importance of phase III of the migrating myoelectric complex (MMC) for homeostasis of enteric flora is well documented. The goal of this study was to evaluate in an isogeneic rat model the effect of MMC changes on the self-purging capacity of the jejunal graft. The proximal 25% of the entire jejunoileum of Lewis rats was transplanted orthotopically. Electrodes were then fixed to the graft. Native bowel of five rats and five rats with analogue jejunal segmentation served as controls. Myoelectric recordings were carried out until day 21, when animals were killed for bacteriologic analysis of the segments analyzed myoelectrically and the of neighboring gut. MMCs were observed in all animals during all recordings. Phase III was irregular in transplants because of long-lasting periods of phase III absence alternating with phase III occurring more frequently. The variation coefficient of phase III periodicity calculated for grafts was 48.74, for native bowel 14.79, and for segmented jejunum 22.9. Enteric flora found in all specimens consisted of colonic-like microorganisms. Titers of microorganisms in grafts did not differ from control segments. These findings show that phase III periodicity is severely altered in jejunal grafts. Homeostasis of enteric flora, however, is not influenced by the transplant procedure.

Early determination of neurological outcome after prehospital cardiopulmonary resuscitation.

BACKGROUND AND PURPOSE: Although there are various methods of determining neurological prognosis after cardiopulmonary resuscitation, the final outcome of patients often remains unclear for quite a long time. METHODS: We investigated 30 consecutively admitted patients who had been successfully resuscitated by the team of the local mobile intensive care unit after cardiac arrest. Determinations of the period of anoxia and of the cardiopulmonary resuscitation time, clinical investigation, echocardiography, electroencephalography, evoked potentials, magnetic resonance imaging, and magnetic resonance spectroscopy were performed. RESULTS: Demonstration of brain lactate in proton magnetic resonance spectroscopy (P < .01) and absent N20 waves in short-latency somatosensory evoked potentials (P < .01) proved to be significant in terms of a poor prognosis. Correlations between both duration of anoxia and cardiopulmonary resuscitation time and neurological outcome could be shown as well (both P < .05). CONCLUSIONS: Proton magnetic resonance spectroscopy and short-latency evoked potentials are of great benefit in the prognostic evaluation after cardiopulmonary resuscitation.

Presence of Klùver-Bucy syndrome as a positive prognostic feature for the remission of traumatic prolonged disturbances of consciousness.

After severe brain injury a prolonged disturbance of consciousness may occur, sometimes with transient apallic syndrome (awakening without awareness of self and surroundings). Klùver-Bucy is described in the literature as a typical post-traumatic remission phase, in which the patients show an increase of oral automatisms and/or of sexual drive. The study describes Klùver-Bucy syndrome as a sign associated with favourable prognosis in the outcome of traumatic disturbances of consciousness in survivors of head trauma. Seventy-seven patients who had suffered severe brain injury due to traffic accidents entered into the study. All had experienced a relatively benign clinical course since they recovered full awareness, that is were able to communicate with their relatives. The occurrence of prolonged coma, of apallic syndrome and of Klùver-Bucy syndrome are related to outcome date in regards to the patient's work and family function at a mean of 32 months later. In particular, the duration of the apallic syndrome (duration of unconsciousness) was significantly correlated with the global outcome of the patients (p < 0.001).

Sleep spindles in the initial stages of the vegetative state.

The aim of this study was to look for the presence of spindling in the different stages of remission of the vegetative state to underline all possible correlations with lesional sites, severity of coma and final outcome. The nocturnal polygraphic recordings from 30 patients were examined: 20 (15M, 5F, mean age 31.7 years, range 16-41) had originally suffered a traumatic brain injury, 10 (4M, 6F, mean age 40.5 years, range 24-48) had hypoxic brain lesions. Evidence of spindling, always reduced in density and duration, was found in 44% of these patients, prevalently in the traumatic patients (53.3% versus 30% of hypoxic patients). No subjects in the full stage 0, 0-1 of the vegetative state (apallic syndrome) presented spindling. No significant correlation was found between spindling and the following parameters: gender, the time between the onset of coma and the polygraphic recording, or the site of the lesion.

Sleep in the last remission stages of vegetative state of traumatic nature.

Polygraphic studies were carried out on 20 patients (13 male, 7 female, average age 25.3 years) in the last remission stages of a traumatically caused vegetative state (apallic syndrome: stages V-VIII according to Gerstenbrand's classification). The presence of all the stages of NREM and REM sleep was observed in all patients, as was typical spindling activity. With respect to patients in the first remission stages of vegetative state, the total sleep time (TST) was seen to increase as a percentage of the total time in bed (95%) and with respect to TST, the periods of waking after a period of sleep diminished (wake after sleep onset: 9.73%). Stage I decreased (10.39%), while stages II-III-IV increased (32.36%, 4.29% and 6.04% respectively). There was a clear increase in the REM percentage (37.19%); spindling rate and index both increased (4.9/min and 12.1 respectively).

Post-traumatic mutism.

We report on the infrequent verbalisation disorder called "post-traumatic mutism" observed in 12 subjects with severe traumatic head injuries. These patients during the recovery of their conditions showed for a certain period a speechlessness even though some of them could communicate through gestures and writing. The nature and the possible mechanism of the disorder are discussed.

Myoelectric activity during small bowel allograft rejection.

The effect of rejection on myoelectric activity of an orthotopically transplanted small intestinal segment (group I, N = 14) was studied. Electrodes were placed on grafts and recipient small bowel. Isografts (group II, N = 5) and native bowel (group III, N = 5) served as controls. The first morphological signs of rejection were seen on day 6 and steadily progressed until day 11, when the cellular infiltrate involved all layers of the bowel wall. Slow-wave frequencies remained unchanged throughout the observation period. No difference was detectable between grafts (group I: 31.9 +/- 1.65; group II: 31.36 +/- 0.7) and native bowel after transection (group I: 32.16 +/- 1.78; group II: 31.50 +/- 1.01), which was different (P = 0.0001) from intact bowel of group III animals (38.4 +/- 0.81). Irregular MMCs were detectable in grafts from day 5 on and replaced after food intake by random spiking activities. At day 8, spiking activities disappeared in allografts, which showed a still preserved mucosal architecture, while slow-wave activities continued. These findings demonstrate that intestinal allografts during rejection develop paralysis before mucosal destruction is established, which might be of clinical relevance.