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PubMedDate not supplied

Recovery plateau following stroke: fact or fiction?

PURPOSE: 'Plateau' is an expression frequently used in relation to decisions to discharge patients from physiotherapy following stroke. This paper critically considers the concept of recovery plateau in stroke, exploring (i) the evidence for plateau, (ii) potential contributing factors, and (iii) the consequences for patients, therapists and services. SEARCH STRATEGY: The concept of recovery plateau in stroke was reviewed drawing on standard critical appraisal methodology for the search strategy and critique. Electronic searches using Web of Knowledge, MEDLINE, CINAHL, Department of Health Website and the Cochrane Library from the earliest dates of coverage until February 2005 identified quantitative and qualitative literature related to stroke, plateau, recovery, outcome, rehabilitation and physiotherapy. DISCUSSION: The concept of plateau is ambiguous. Recovery has been considered to plateau within the first 6 months, yet recent studies indicate later recovery is possible. We suggest that 'plateau' relates not only to the patient's physical potential, but is influenced by how recovery is measured, the intensity and type of therapy, patients' actions and motivations, therapist values, and service limitations. CONCLUSION: 'Plateau' is conceptually more complex than previously considered. Current conceptualizations may limit potential recovery and hinder service development. Research into plateau which takes account of contextual issues of therapy provision is required.

Attitude of Health Personnel↗

PubMed2005

Electrical stimulation of the vagus nerve enhances cognitive and motor recovery following moderate fluid percussion injury in the rat.

Intermittent, chronically delivered electrical stimulation of the vagus nerve (VNS) is an FDA-approved procedure for the treatment of refractory complex/partial epilepsy in humans. Stimulation of the vagus has also been shown to enhance memory storage processes in laboratory rats and human subjects. Recent evidence suggests that some of these effects of VNS may be due to the activation of neurons in the nucleus locus coeruleus resulting in the release of norepinephrine (NE) throughout the neuraxis. Because antagonism of NE systems has been shown to delay recovery of function following brain damage, it is possible that enhanced release of NE in the CNS may facilitate recovery of function. To evaluate this hypothesis the lateral fluid percussion injury (LFP) model of traumatic brain injury was used and a variety of motor and cognitive behavioral tests were employed to assess recovery in pre-trained stimulated, control, and sham-injured laboratory rats. Two hours following moderate LFP, vagus nerve stimulation (30.0-sec trains of 0.5 mA, 20.0 Hz, biphasic pulses) was initiated. Stimulation continued in each animal's home cage at 30-min intervals for a period of 14 days, with the exception of brief periods when the animals were disconnected for behavioral assessments. Motor behaviors were evaluated every other day following LFP and tests included beam walk, locomotor placing, and skilled forelimb reaching. In each measure an enhanced rate of recovery and /or level of final performance was observed in the VNS-LFP animals compared to nonstimulated LFP controls. Behavior in the Morris water maze was assessed on days 11-14 following injury. Stimulated LFP animals showed significantly shorter latencies to find the hidden platform than did controls. Despite these behavioral effects, neurohistological examination did not reveal significant differences in lesion extent, density of fluorojade positive neurons, reactive astrocytes or numbers of spared neurons in the CA3 subarea of the hippocampus, at least at the one time point studied 15 days post-injury. These results support the idea that vagus nerve stimulation enhances the neural plasticity that underlies recovery of function following brain damage and provides indirect support for the hypothesis that enhanced NE release may mediate the effect. Importantly, since VNS facilitated both the rate of recovery and the extent of motor and cognitive recovery, these findings suggest that electrical stimulation of the vagus nerve may prove to be an effective non-pharmacological treatment for traumatic brain injury.

Animals↗

PubMed2006

Delayed intervention with transplants and neurotrophic factors supports recovery of forelimb function after cervical spinal cord injury in adult rats.

The adult central nervous system is capable of considerable anatomical reorganization and functional recovery after injury. Functional outcomes, however, vary greatly, depending upon size and location of injury, type and timing of intervention, and type of recovery and plasticity evaluated. The present study was undertaken to assess the recovery of skilled and unskilled forelimb function in adult rats after a C5/C6 spinal cord over-hemisection and delayed intervention with fetal spinal cord transplants and neurotrophins. Recovery of forelimb function was evaluated during both target reaching (a skilled behavior) and vertical exploration (an unskilled behavior). Anatomical tracing and immunohistochemistry were used to assess the growth of descending raphespinal, corticospinal, and rubrospinal fibers at the injury site, tracts that normally confer forelimb function. Delayed intervention with transplants and either brain-derived neurotrophic factor (BDNF) or neurotrophin-3 (NT-3) restored skilled left forelimb reaching to pre-injury levels. Animals showed recovery of normal reaching movements rather than compensation with abnormal movements. Transplants and NT-3 also improved right forelimb use during an unskilled vertical exploration, but not skilled right reaching. Intervention with fetal transplant tissue supported the growth of descending serotonergic, corticospinal, and rubrospinal fibers into the transplant at the lesion site. The addition of neurotrophins, however, did not significantly increase axonal growth at the lesion site. These studies suggest that the recovery of skilled and unskilled forelimb use is possible after a large cervical spinal cord injury following delayed intervention with fetal spinal cord and neurotrophins. Plasticity of both spared and axotomized descending pathways likely contributes to the functional recovery observed.

Animals↗

PubMed1992

Recovery of cognitive functions after anaesthesia with desflurane or isoflurane and nitrous oxide.

We studied recovery in 25 adult patients, ASA I, undergoing elective orthopaedic procedures after anaesthesia with 0.65 MAC desflurane (n = 16) or isoflurane (n = 9) with 60% nitrous oxide in oxygen. Early emergence from anaesthesia was assessed in the operating room by measuring time to spontaneous movement, cough, response to painful pinch, tracheal extubation, opening of the eyes and stating correct age, name and body parts. The return of cognitive functions in the late recovery phase was assessed in the post-anaesthesia care unit (PACU) by post-anaesthesia recovery scores (PARS), the Trieger dot test (TDT), and the digit substitution test (DST). In the early recovery phase, time to tracheal extubation, opening eyes, telling correct name, age and body parts occurred significantly faster in the desflurane group than in the isoflurane group (P < 0.05). The mean "triple orientation" time (to name, age, body parts) was 10.9 (SEM 0.9) min for desflurane, compared with 18.6 (2.5) min for isoflurane (P < 0.01). In the late recovery phase, desflurane patients had significantly greater PARS, more correct responses to the DST and fewer error responses to the TDT. Recovery times were not increased by increased duration of desflurane anaesthesia. The desflurane patients showed no delirium, minimal sedation and less shivering during the entire postoperative course. We conclude that desflurane anaesthesia was superior to isoflurane anaesthesia, not only in emergence, but also in the recovery of cognitive functions.

Adolescent↗

PubMed2003

Recovery of elderly patients from two or more hours of desflurane or sevoflurane anaesthesia.

BACKGROUND: The solubility of desflurane compared with sevoflurane suggests more rapid recovery from desflurane anaesthesia. This could be important after prolonged anaesthesia and fast recovery may be advantageous in the elderly where slow recovery of mental function is a concern. We compared emergence from desflurane vs sevoflurane in elderly patients undergoing two or more hours of anaesthesia. METHODS: Fifty ASA physical status I, II, or III patients, 65 yr of age or older, undergoing anaesthesia expected to last two or more hours were randomly assigned to receive desflurane/nitrous oxide or sevoflurane/nitrous oxide anaesthesia. Patients were given 1-2 microg x kg(-1) fentanyl i.v. and anaesthesia was induced with propofol 1.5-2.5 mg x kg(-1) i.v. and maintained with either desflurane 2-6% or sevoflurane 0.6-1.75% with nitrous oxide 65% in oxygen. Inspired anaesthetic concentrations were adjusted to obtain adequate surgical anaesthesia and to maintain mean arterial pressure within 20% of baseline values. Early and intermediate recovery times were recorded. Digit-Symbol Substitution Test (DSST) scores and Visual Analog Scale (VAS) scores for pain and nausea were recorded before pre-medication and every 15 min in the Post Anaesthesia Care Unit (PACU) until patients were discharged. RESULTS: Early recovery times are given as median, quartiles. The times to extubation (5 (4-9); 9 (5-13) min), eye opening (5 (3-5); 11 (8-16) min), squeezing fingers on command (7 (4-9); 12 (8-17) min); and orientation (7 (5-9); 16 (10-21) min) were significantly less (P<0.05) for desflurane than for sevoflurane. Intermediate recovery, as measured by the DSST and time to ready for discharge from the PACU (56 (35-81); 71 (61-81) min) was similar in the two groups. CONCLUSIONS: Early but not intermediate recovery times of elderly patients undergoing a wide range of surgical procedures requiring two or more hours of anaesthesia is significantly (P<or=0.05) faster after desflurane.

Aged↗

PubMed2005

Corticospinal regeneration into lumbar grey matter correlates with locomotor recovery after complete spinal cord transection and repair with peripheral nerve grafts, fibroblast growth factor 1, fibrin glue, and spinal fusion.

Knowledge of which tracts are essential for the recovery of locomotor function in rats after repair is unknown. To assess the mechanism of recovery, we examined the correlation between functional recovery and axonal regeneration. All rats underwent complete cord transection and repair with peripheral nerves, fibroblast growth factor 1, fibrin glue, and spinal fixation. Repaired rats recovered both motor-evoked potentials recorded at the lumbar level and locomotor function. Cord retransection rostral to the repair abolished the recovery, indicating improvement was due to long tract regeneration. To determine which long tracts correlated with recovery, a novel technique of simultaneous bidirectional axonal tracing and immunohistochemical examination of axonal type was used to quantitate the regeneration of corticospinal, rubrospinal, reticulospinal, vestibulospinal, raphespinal, propriospinal, serotonergic, and calcitonin gene-related peptide containing axons. Multiple linear regression analysis revealed recovery of function correlated only with regeneration of corticospinal axons into the gray matter of the lumbar spinal cord (R = 0.977, p < 0.02). For the first time, we show that regeneration of the corticospinal tract into the lumbar gray matter is a mechanism of functional locomotor recovery after complete cord transection and repair.

Amino Acids↗

PubMed1996

Spontaneous versus edrophonium-induced recovery from paralysis with mivacurium.

This study compared spontaneous with edrophonium-induced recovery of neuromuscular transmission (NMT) after mivacurium infusion. During nitrous oxide-narcotic-propofol anesthesia, the electromyogram (EMG) of the adductor pollicis (AP) was recorded and the movement of the first toe in response to stimulation of the posterior tibial nerve was noted. Mivacurium infusion was titrated to produce posttetanic count of 1-5 at the toe and absence of NMT at the AP. Thirty children were assigned to three groups on the basis of age. Edrophonium, 1 mg/kg, with atropine 10 micrograms/kg, was given after the mivacurium infusion when NMT of the AP was 1% or 10% of baseline. In the third group, spontaneous recovery was observed. Edrophonium given when NMT was 11% +/- 1% SEM produced the most rapid recovery, 7.5 +/- 0.6 min to a train-of-four (TOF) ratio (T4/T1) of 0.9 and the shortest interval from T4/T1 of 0.4-0.9, when residual block was likely to be underestimated, 4.8 +/- 0.6 min. Edrophonium given when block was greater produced recovery of the T4/T1 to 0.4 in 2.8 +/- 0.7 min, but the time from then to T4/T1 = 0.9 was 7.9 +/- 1.1 min, as long as during spontaneous recovery. Spontaneous recovery to T4/T1 = 0.9 occurred 12.9 +/- 0.7 min after the first measurable AP EMG. There was no significant relationship between duration of infusion, which ranged from 16 to 135 min, and time to appearance of AP EMG after the infusion, which averaged 3.1 +/- 0.5 min. We recommend that administration of edrophonium to induce reversal of mivacurium be delayed until two responses to a TOF stimuli are observed because this will produce the most rapid recovery and decrease the interval in which residual block may be underestimated.

Anesthesia Recovery Period↗

PubMed1992

Oxygen uptake during recovery following naloxone. Relationship with intraoperative heat loss.

The increased metabolic and respiratory demand during naloxone recovery from opioid-based anesthesia could be related to the return of thermoregulation in hypothermic patients and thus be avoided by preventing intraoperative hypothermia. In this study, we measured O2 uptake (VO2) during naloxone-induced recovery in two groups of patients to determine the effect of intraoperative heat loss on postoperative VO2 changes. In seven patients, intraoperative hypothermia was prevented (normothermic group), whereas hypothermia was allowed to develop in seven other patients (hypothermic group). Core and skin temperatures were measured throughout the study to calculate changes in body heat content. Before naloxone antagonism of fentanyl-supplemented anesthesia, core temperature (mean +/- SEM) was 36.8 +/- 0.1 degrees C in the normothermic group and 34.2 +/- 0.2 degrees C in the hypothermic group (P less than 0.001). After titrated administration of naloxone during recovery, VO2 and minute ventilation (VE) increased in the hypothermic group, by 114 +/- 37% and 97 +/- 52% respectively (P less than 0.05), with a three-fold increase in four patients. In the normothermic group, VO2 increased significantly less (25 +/- 5%), without any significant change in VE. The change in VO2 and VE was significantly greater in patients who were hypothermic. VO2 was integrated throughout the recovery period to calculate recovery energy expenditure. Recovery energy expenditure and intraoperative heat loss were highly correlated (r = 0.88; P less than 0.01). This study demonstrates that the metabolic and respiratory stresses associated with naloxone-induced recovery from opioid-based anesthesia depend on the intraoperative heat loss and can therefore be reduced by preventing intraoperative hypothermia.

Anesthesia Recovery Period↗

PubMedDate not supplied

Analysis of recovery processes after stroke by means of transcranial magnetic stimulation.

The objective of this study was to use motor evoked potentials (MEPs) to analyze the integrity of fast corticospinal functions as the neurophysiologic basis for motor recovery in stroke patients. This was a cohort study including 44 acute stroke patients with paralysis of the upper or the lower extremity. Motor evoked potentials of the abductor digiti minimi, the biceps brachii, the vastus medialis, and the tibialis anterior were performed within 10 days (mean, 6.9 days; range, 3 to 10 days) and 40 days (mean, 27.8 days; range, 14 to 40 days) after stroke onset. A separate score was defined for proximal and distal motor functions of the upper and lower extremity within the original Fugl-Meyer motor assessment. Motor performance was evaluated simultaneously with the MEP assessments and 26 weeks after stroke. For all the muscles in which a response was present during the first investigation, obvious recovery of the fast corticospinal functions occurred. For the abductor digiti minimi amplitude ratio and the vastus medialis MEP amplitude the differences between the two investigations were significant. An MEP response could be elicited in more cases at the second than on the first MEP assessment. A present MEP response during the first registration indicated nearly always subsequent motor recovery, both for proximal and distal motor functions of the upper and lower extremity. However, motor recovery was also observed in some patients for whom no MEP response could be elicited. Regression analysis showed significant relationships between the abductor digiti minimi (P = 0.020/0.004 [t1/t2])and biceps brachii (P = 0.020/0.004 [t1/t2]) MEP amplitude parameters and the 26-week hand and arm motor scores. No relationship existed between the tibialis anterior and the vastus medialis MEP parameters and the leg motor scores. Motor recovery manifests neurophysiologically often as the recovery of fast corticospinal functions. In many cases, assessment by MEPs is more sensitive than clinical examination to detect residual corticospinal functions, which forms the pathophysiologic basis for the predictive value of MEPs for motor recovery after stroke.

Adult↗

PubMed2004

Asynchronism of the recovery of baroreflex sensitivity, blood pressure, and consciousness from anesthesia in rats.

Anesthesia inhibits arterial baroreflex functions such as baroreflex sensitivity (BRS). The main objective of the present study was to determine the time course of BRS recovery from anesthesia and to determine whether BRS recovery is synchronous with the recovery of consciousness and blood pressure (BP). Experiments were performed in male Sprague-Dawley rats using different commonly used anesthetics at routine doses through intraperitoneal administration: (1) diazepam/ketamine, a mixture of diazepam (5 mg/kg) and ketamine (50 mg/kg); (2) chloral hydrate (0.3 g/kg); (3) sodium pentobarbital (30 mg/kg); and (4) urethane (1.0 g/kg). The anesthetic state, evaluated by algesthesia and cornea reflex, was maintained for 1-2.5 hours. The BRS, assessed by intravenous injection of phenylephrine, was inhibited rapidly and dramatically, with maximum depressions of 51%-80%. The BRS recovery time was approximately 5 hours for diazepam/ketamine, chloral hydrate, and pentobarbital, but more than 24 hours for urethane. Compared with BRS inhibition, BP reduction was less pronounced by 8% (not significant) for diazepam/ketamine and by 12%-30% for the others. The BP recovery time was approximately 2 hours, with the exception of chloral hydrate (>6 hours). In conclusion, after anesthesia, BRS inhibition is more obvious than BP reduction, and the recovery of BRS lags behind the recovery of consciousness or BP.

Anesthesia Recovery Period↗

PubMed2000

Reduced recovery of temporal contrast sensitivity after flicker stress in patients with glaucoma.

PURPOSE: To compare recovery of temporal contrast sensitivity after flicker stress between control subjects and patients with glaucoma. METHODS: Forty-three patients with primary open-angle glaucoma and secondary open-angle or normal-tension glaucoma of the Erlangen Glaucoma Registry and 30 healthy control subjects had their temporal contrast sensitivity measured at 37 Hz and their recovery time determined after monocular exposure to 30 seconds of 58% contrast full-field flicker. Recovery time of temporal contrast sensitivity was measured as the time interval from cessation of flicker until twice the threshold value was reached. RESULTS: Patients with glaucoma had a significant reduction in temporal contrast sensitivity (P < 0.001). Recovery time was also significantly longer in patients with glaucoma (23.8 +/- 24.1 seconds) than in control subjects (7.6 +/- 2.6 seconds; P < 0.001). There was a significant positive correlation between recovery time and mean visual field defect (0.5; P < 0.001) and a significant negative correlation between recovery time and neuroretinal rim area of the optic disc (0.32; P = 0.04). CONCLUSIONS: Recovery of temporal contrast sensitivity after flicker stress is impaired in some patients with glaucoma. This might be the result of functional impairment of the inner retina, outer retina, or both in glaucoma.

Adaptation, Ocular↗

PubMed2003

Occupational recovery after open-door type laminoplasty for patients with ossification of the posterior longitudinal ligament.

STUDY DESIGN: A cross-sectional survey of occupational recovery after surgery with patients who had ossification of the posterior longitudinal ligament. OBJECTIVES: To evaluate occupational recovery after open-door type laminoplasty for patients with ossification of the posterior longitudinal ligament. SUMMARY OF BACKGROUND DATA: The literature contains numerous reports on the surgical results of laminoplasty for ossification of the posterior longitudinal ligament, but very few reports are available on postoperative quality of life, and even fewer on occupational recovery after laminoplasty. METHODS: A cross-sectional survey was conducted of 301 patients with ossification of the posterior longitudinal ligament in the cervical spine who were employed before open-door type laminoplasty. Presurgical occupations were classified into three categories: light sedentary labor, light standing labor, and heavy labor. High-rise workers and professional drivers were analyzed separately. The subjects were rated by occupational category for determining the occupational recovery ratio. Factors analyzed for impact on recovery were pre- and postsurgery severity of myelopathy, duration of myelopathy, age at surgery, gender, and type of ossification of the posterior longitudinal ligament. RESULTS: Of the 301 patients studied, 160 (53%) returned to work. Poor recovery rates were observed for heavy labor, high-rise workers, and professional drivers. The period required for return to work did not significantly differ among occupational categories. Occupation, presurgery severity of myelopathy, and postsurgery severity of myelopathy were significantly correlated with occupational recovery. CONCLUSION: Patients' occupations should be carefully considered when designing postsurgery occupational rehabilitation programs, and patients should receive postoperative advice regarding the suitability of occupation.

Cross-Sectional Studies↗

PubMedDate not supplied

The role of rumination in recovery from reactivity: cardiovascular consequences of emotional states.

OBJECTIVE: While most investigations of the link between blood pressure responses and later disease have focused on acute reactivity during stressful tasks, there is some theoretical and empirical reason to believe that examining recovery and later re-creations of BP responses may also be useful. Two experiments explored situational determinants of sustained BP elevations, examining whether the extent of recovery and the ability to later mentally recreate the response are influenced by the magnitude or emotionality of the initial task and also whether preventing rumination after a stressor has ended speeds recovery. METHOD: Experiment 1, with 72 normotensive male and female undergraduates, examined BP and heart rate before, during, and after a task and also before, during, and after the mental re-creation of that task. Four tasks were used, designed to produce high initial reactivity with an emotional component (mental arithmetic with harassment), low reactivity with emotion (shock avoidance), high reactivity without emotion (physical exercise), or low reactivity without emotion (cold pressor). Experiment 2, with 20 normotensive male and female undergraduates, compared the cardiovascular recovery of persons who were either given a distractor task or just sat quietly immediately after a mental arithmetic task. RESULTS: Study 1 revealed that only the emotional tasks were associated with delayed BP recovery and elevations during later rumination. Blood pressure during recovery and later rumination was independent of the original reactivity. Experiment 2 found that participants with the distractor, who presumably could not ruminate, showed better BP recovery. CONCLUSIONS: Situations that put people at risk may include not just those that cause large BP elevations, but also emotion-producing situations that lead to sustained and recurring elevations.

Adult↗

PubMed2005

Endocrinological and catecholaminergic alterations during sleep deprivation and recovery in male rats.

Since previous data of our group showed increased concentrations in HPA axis hormones in sleep deprived rats, we hypothesized that this augmentation could produce effects in other hormonal systems, particularly in the sexual system. Considering that little is known about how the hormonal system changes during the recovery period after sleep deprivation (SD), our objective was to examine from what point SD alters sexual and stress-related hormones along with plasma catecholamine concentrations during 4 days. We also sought to verify the time course of their recovery after an equivalent period of recovery sleep. Rats were deprived of sleep by the platform technique for 1-4 days and were allowed to recover for the same period. Plasma catecholamines [dopamine (DA) and noradrenaline (NOR)], testosterone, estrone, progesterone, prolactin, corticosterone and adrenocorticotropic hormone (ACTH) concentrations were measured. Comparisons between groups showed that the SD procedure used in the present study produced marked alterations in almost all studied hormones from 24 h of SD, except for estrone and prolactin (which required 96 h of SD to become altered). Testosterone and estrone decreased, whereas progesterone, prolactin, corticosterone, ACTH, DA and NOR increased. During recovery period, progesterone, prolactin and corticosterone concentrations returned to control levels, whereas testosterone, estrone, NOR and DA did not. In addition, after 48 h of recovery ACTH and NOR decreased below control concentrations, remaining low until 96 h of sleep recovery. Thus, SD showed long lasting, differential effects upon these neurochemicals suggesting that each has its own pattern of responses to SD as well as variable periods of recovery.

Adrenocorticotropic Hormone↗

PubMed1997

Recovery and outcome after propofol and isoflurane anesthesia in patients undergoing laparoscopic hysterectomy.

BACKGROUND: Laparoscopic hysterectomy (LH) is expected to provide fast and comfortable recovery, plus an early return to normal daily activities. This study was carried out to compare the outcome after LH in patients anesthetized with isoflurane or propofol. METHODS: Sixty-two patients undergoing LH were randomized to receive either isoflurane-N2O or propofol-N2O anesthesia. The times when the patients could drink, void and walk were recorded. Recovery was also evaluated by the Digit Symbol Substitution Test in the postanesthesia care unit (PACU) 60 and 120 min after the operation. The patients were also given a questionnaire on their further recovery (return to daily activities, pain and nausea) to be filled out at home. RESULTS: Early recovery was significantly (P < 0.05) faster in the isoflurane group (eye opening within 3 min, orientation in 6 min) when compared to the propofol group (eye opening within 7 min, orientation in 14 min), but there was no significant difference in the other parameters of recovery. Most of the patients were discharged from the hospital on the first postoperative day in both groups. Twenty-five percent of the patients, however, stayed two nights in hospital, mainly for social reasons. No difference was found regarding the recovery at home: the patients resumed their normal daily activities on about the sixth postoperative day (median). CONCLUSIONS: It is concluded that both isoflurane and propofol are suitable anesthetics for LH. In this study recovery was not fast enough to make the patients suitable for same-day surgery.

Adult↗

PubMed2006

Circulating insulin-like growth factor I and functional recovery from spinal cord injury under enriched housing conditions.

Voluntary locomotor training as induced by enriched housing of rats stimulates recovery of locomotion after spinal cord injury (SCI). Generally it is thought that spinal neural networks of motor- and interneurons located in the ventral and intermediate laminae within the lumbar intumescence of the spinal cord, also referred to as central pattern generators (CPGs), are the 'producers of locomotion' and play a pivotal role in the amelioration of locomotor deficits after SCI. It has been suggested that locomotor training provides locomotor-specific sensory feedback into the CPGs, which stimulates remodeling of central nervous system pathways, including motor systems. Several molecules have been proposed to potentiate this process but the underlying mechanisms are not yet known. To understand these mechanisms, we studied the role of insulin-like growth factor (IGF) I in functional recovery from SCI under normal and enriched environment (EE) housing conditions. In a first experiment, we discovered that subcutaneous administration of IGF-I resulted in better locomotor recovery following SCI. In a second experiment, detailed analysis of the observed functional recovery induced by EE revealed full recovery of hindlimb coordination and stability of gait. This EE-dependent functional recovery was attenuated by alterations in the pre-synaptic bouton density within the ventral gray matter of the lumbar intumescence or CPG area. Neutralization of circulating IGF-I significantly blocked the effectiveness of EE housing on functional recovery and diminished the EE-induced alterations in pre-synaptic bouton density within the CPG area. These results support the use of IGF-I as a possible therapeutic aid in early rehabilitation after SCI.

Animals↗

PubMed2004

Parasympathetic effects on heart rate recovery after exercise.

BACKGROUND: Exercise and its recovery period are associated with increased risk of death relative to sedentary periods. They are also accompanied by dynamic changes in autonomic tone. Little information is available regarding parasympathetic effects during high-intensity exercise and recovery. METHODS: Ten normal subjects (five women; age 33 +/- 2 years) underwent exercise testing on a bicycle ergometer. On day 1, subjects exercised to maximum tolerated workload using a graded protocol with 5 minutes at maximal workload (peak heart rate achieved 174.7 +/- 5.4 bpm). On day 2, subjects performed the identical exercise protocol as on day 1; 1 minute into the maximum exercise stage, atropine (0.04 mg/kg) was administered. Heart rate was recorded every minute during exercise, and an electrocardiogram was recorded every minute in recovery for 10 minutes. The parasympathetic effect on heart rate was defined by the difference in heart rate with and without atropine. RESULTS: The parasympathetic effect during maximal exercise was 3.4 to 6 bpm (p < .05). During recovery, a large parasympathetic effect on heart rate was noted by 1 minute (22.8 bpm; p < .0002), increased until 4 minutes, and then remained stable until 10 minutes. Despite faster heart rates with parasympathetic blockade, the P-R interval was shorter (p < .002), consistent with a significant parasympathetic effect on the atrioventricular node in recovery. Evaluation of the Q-T-R-R relationship on the 2 days demonstrated significant changes in both the slope (p < .0001) and the intercept (p < .0001), consistent with a modification of ventricular repolarization by parasympathetic tone in recovery. CONCLUSION: These data indicate that in normal subjects, parasympathetic effects persist during high-intensity exercise and are prominent in the early phases of recovery. These parasympathetic effects may play an important role in prevention of sudden cardiac death during these periods of increased risk.

Adult↗

PubMed2000

Reactivity and recovery from different types of work measured by catecholamines and cortisol: a systematic literature overview.

OBJECTIVES: To review occupational health, laboratory, and sports literature on neuroendocrine reactivity and recovery from mental, combined mental and physical, or physical tasks. METHODS: A systematic literature search was performed in eight databases. Studies with catecholamines or cortisol as effect variables measured in blood, urine, or saliva were included. RESULTS: After application of inclusion and exclusion criteria, 77 studies from the initial 559 identified were taken into account. In occupational settings it was found that relatively few studies were conclusive about recovery, which formed a contrast with sports research. For reactivity and recovery up to 1 hour after performing the task, half of the studies considered physical tasks and more than two thirds showed incomplete recovery compared with baseline excretion of catecholamines and cortisol. Recovery extending to 3 days after the task was performed was often incomplete for cortisol after combined mentally and physically demanding tasks, and less often after solely mental or physical tasks. This type of recovery was more often incomplete for adrenaline (epinephrine) than for noradrenaline (norepinephrine), which was the case after mental as well as combined mental and physical tasks. CONCLUSIONS: The results from laboratory and sports research may be transferable to some occupations, but more research is needed on the course of recovery relative to health effects in occupational settings.

Biomarkers↗