Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0038454 (stroke)
 147,016 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The objective of this study was to determine if 1,3-butanediol would reduce a neurologic deficit in rats exposed to ischemic-hypoxia (Levine rats). Age and weight matched male Sprague-Dawley rats were anesthetized with 2% halothane. The right common carotid and external jugular vein were ligated and cannulated and EEG screws were implanted followed by a 2 hour recovery period. Thirty minutes prior to exposure the rats received either 1,3-butanediol (47 mmole/kg i.v.; n = 11) or an equal volume of saline (n = 10). The rats were then exposed to 4.5% O2 until mean arterial blood pressure fell to 70 mm Hg. The oxygen level was then increased to 8% for 30 minutes, after which the rats were returned to room air. Posture, hemiparesis, circling, shuffling, activity, and ability to hang on to a vertical screen were scored 1 (normal) to 5 (severe deficit) at 2 and 20 hours after insult. The time to 70 mm Hg was extended from 7.9 +/- 0.9 min for saline treated rats to 19.0 +/- 2.3 min for the 1,3-butanediol treated rats (p less than 0.001). All eleven 1,3-butanediol treated rats survived the hypoxic insult; 90% (9/10) saline treated rats died. In an attempt to reduce the insult, six additional saline treated rats were switched to 8% O2 at 75 mm Hg and still 4/6 died. The mean score at 20 hours for three surviving saline treated rats was 3.4. A significantly better (p less than 0.002) mean 20 hour score for the surviving 8/11 1,3-butanediol treated rats was 1.2. 1,3-butanediol increases survival and decreases the neurologic deficits associated with this ischemic-hypoxic insult.
Stroke
PMID:Reduction of neurologic deficit by 1,3-butanediol induced ketosis in levine rats. 404 49

With the ultimate goal to better demonstrate the biomechanics of spastic paretic stiff-legged gait, we simulated the motion of this gait disability, based on actual kinematic gait data. We created and applied a seven link-segment forward dynamic model to the gait kinematics of five adult subjects with this gait disability as a result of stroke. Trunk and limb segment torques developed during the affected limb's swing period of gait were calculated via inverse dynamic techniques from the measured kinematic data and incorporated into the forward dynamic model to simulate motion. In each case, the simulated motion corresponded to the directly measured kinematics. The hip and knee torques were then altered to predict potential resultant changes in knee flexion. Preliminary results suggest a stronger effect of hip torque than knee torque on knee angle, which also qualitatively corresponded with clinical data. This study demonstrates the feasibility of forward dynamic modelling based on actual clinical data and provides a further means to analyze potential mechanisms of this gait disability. Copyright 1997 Elsevier Science B.V.
Gait Posture 1998 Mar 01
PMID:The modelling of adult spastic paretic stiff-legged gait swing period based on actual kinematic data. 1020 Mar 81

Moment arms of tibialis anterior (TA) and tibialis posterior (TP) about the subtalar and talocrural joint axes were measured in anatomic specimens both before and after split tendon transfers. These procedures are commonly performed to correct hindfoot varus, a gait deformity that is often seen in patients with cerebral palsy, stroke, and brain injury. Split tendon transfer significantly reduced the inversion moment arms of tibialis anterior and tibialis posterior at all subtalar joint angles except for the most everted position in the case of TA. Changes in subtalar joint moment arms produced by split tendon transfer, especially those seen in TA, were variable, suggesting that the procedure may be susceptible to technical errors, especially related to balancing tensions in the medial and lateral tendon halves. Talocrural joint moment arms of both muscles were preserved following split tendon transfer. This study presents the first measurements of the moment arms of split transferred muscles. These characterizations of the mechanics of split tendon transfer will aid in the planning and assessment of these procedures.
Gait Posture 2001 Dec
PMID:Changes in muscle moment arms following split tendon transfer of tibialis anterior and tibialis posterior. 1160 Mar 31

This study sought an operational definition of parkinsonism in elderly people (n = 2,914) who underwent a clinical examination in the Canadian Study of Health and Aging (CSHA). Parkinsonism was defined as having two of the following features: (1) bradykinesia of face or limbs, (2) resting tremor, (3) rigidity, and (4) abnormality of gait and posture. The association of parkinsonism with other parkinsonian-related features (prior diagnosis of Parkinson's disease, use of drugs with extrapyramidal side effects, and use of antiparkinsonian medications) and variables not expected to be related to parkinsonism (stroke and Hachinski score > 5) was determined. Parkinsonism was identified in 337 people (11.6%). It was significantly more likely with other parkinsonian-related characteristics, and was not associated with a history of stroke, but was slightly higher among those subjects with a Hachinski score > 5. Posture and gait abnormalities were significantly associated with other parkinsonian-related variables, but were also more common among subjects with stroke-related features. When the gait and posture disturbance category was excluded as a parkinsonian sign, the narrower definition was more specific but less sensitive in detecting cases with a clinical diagnosis of Parkinson's disease. Despite limitations, the approach presented in this article is a valid method to operationalize parkinsonism from the dataset.
 ...
PMID:Defining parkinsonism in the Canadian Study of Health and Aging. 1189 57

This study investigated the role of paresis, excessive antagonist coactivation, increased muscle-tendon passive stiffness and spasticity in the reduced stance phase plantarflexor moment (Mmax) and swing phase dorsiflexion during gait (DFmax) in subjects with a recent (<6 months post-stroke) hemiparesis (patients). The gait pattern of the paretic and non-paretic sides was evaluated in 30 patients (aged 57.8+/-10.8 years), whereas only one side was evaluated in 15 healthy controls (aged 59.1+/-9.8 years) while walking at natural and very slow speeds. Peak plantarflexor moment (Mmax) and peak medial gastrocnemius (MG) activation during the stance phase, as well as peak dorsiflexion angle (Dfmax) and peak tibialis anterior (TA) activation during the swing phase, were retained for analysis. In addition, a coactivation index and a plantarflexor spasticity index were calculated for both the stance and the swing phase, and plantarflexor passive stiffness was evaluated on an isokinetic dynamometer. The results showed that Mmax on the paretic and non-paretic sides were both reduced compared with control values at natural speed. This reduction was combined to a low MG activation (paresis) on the paretic side. On the non-paretic side, the reduced plantarflexor moment was related to excessive coactivation levels. The swing phase Dfmax tended to be reduced (not significantly) on the paretic side of the patients compared with control values. This reduction was neither associated with excessive antagonist coactivation nor to plantarflexor hyperactive stretch reflexes, but rather to an increased plantarflexor passive stiffness. In some of the patients, however, an increased TA activation that overcame the plantarflexor passive stiffness allowed for normal DFmax values. The functional consequences of the disturbed mechanisms of motor control observed in both the paretic and non-paretic sides are discussed.
Gait Posture 2002 Jun
PMID:Mechanisms of disturbed motor control in ankle weakness during gait after stroke. 1198 99

The purpose of this study was to (1) determine whether symmetry in temporal-distance (T-D) measures is accompanied by symmetry in kinetic measures during self-paced gait and (2) evaluate the effect of symmetry on gait speed in individuals with chronic stroke. A symmetry index was calculated for stance time, swing time, step length and vertical ground reaction force (GRF) for 28 individuals with stroke (age: 62.5+/-8.2 years). Spearman correlation revealed that (a) gait speed was correlated with the symmetry of temporal measures and GRF and (b) symmetry in GRF was correlated with symmetry in temporal but not distance measures of gait (P<0.05). The results provide support for promoting temporal and kinetic symmetry in the gait of persons with stroke.
Gait Posture 2003 Aug
PMID:Symmetry in vertical ground reaction force is accompanied by symmetry in temporal but not distance variables of gait in persons with stroke. 1285 97

The mixture of gait deviations seen in patients following a stroke is remarkably variable. An objective system for classification of gait patterns for this population could be used to guide treatment planning. Quantitated gait analysis was conducted for 47 individuals at admission to in-patient rehabilitation and again at 6 months post-stroke for 42 subjects. Non-hierarchical cluster analysis was used to classify the gait patterns of patients based on the temporal-spatial and kinematic parameters of walking. Four clusters of patients were identified at both assessment intervals. At the admission test walking velocity, peak knee extension in mid stance and peak dorsiflexion in swing were the three factors that best characterized the groups. At 6 months the explanatory variables were velocity, knee extension in terminal stance, and knee flexion in pre swing. Differences in muscle strength and muscle activation patterns during walking were identified between groups.
Gait Posture 2003 Aug
PMID:Use of cluster analysis for gait pattern classification of patients in the early and late recovery phases following stroke. 1285 7

The component of foot force generated by muscle action (F(m)) during pedaling in healthy humans has a nearly constant direction with increasing force magnitude. The present study investigated the effect of stroke on the control of foot force. Ten individuals with hemiparesis secondary to a cerebral vascular accident performed pushing efforts against translationally fixed and moving pedals on a custom stationary cycle ergometer. We found that while F(m) direction remained constant with increasing effort in both the fixed- and moving-crank conditions for both limbs, the orientation of that force component differed between limbs. The non-paretic limb produced the same F(m) orientation as seen previously in healthy humans. However, relative to the non-paretic limb, the paretic limb force line-of-action was shifted away from the hip and closer to the knee in the sagittal-plane for both pedal motion conditions. In the frontal plane, the paretic limb force line-of-action was shifted laterally, closer to parallel to the midline, for both pedal motion conditions. These shifts were consistent with previously reported lower limb muscle weakness and alterations in muscle activation observed during pedaling tasks following stroke. The finding of similar orientations for static and dynamic pushing efforts suggests that limb posture could be a trigger for relative muscle activation levels. The preservation of a constant direction in F(m) with increasing force magnitude post-stroke, despite an orientation shift, suggests that control of lower limb force may be organized by magnitude and direction and that these two aspects are differentially affected by stroke.
Gait Posture 2004 Feb
PMID:Foot force direction control during leg pushes against fixed and moving pedals in persons post-stroke. 1474 4

The purpose of this study was to identify 3D kinematic and kinetic gait profiles in individuals with chronic stroke and to determine whether the magnitude or pattern (shape and direction of curve) of these profiles relate to gait performance (as measured by self-selected gait speed). More than one type of kinematic and kinetic pattern was identified in all three planes in 20 individuals with stroke (age: 61.2+/-8.4 years). Persons in the "fast" speed group did not necessarily exhibit the gait patterns closest to the ones reported for healthy adults. For example, in the frontal plane, a variation from the typical pattern (i.e., a hip abductor pattern in swing) was more common among the "fast" group. Correlations revealed that in addition to the sagittal profiles, the magnitudes of the frontal and transverse profiles are also related to speed, particularly the frontal hip powers. The results support the importance of hip abductors, in addition to the sagittal plane muscle groups, for both the paretic and non-paretic limbs. Furthermore, profiles which resemble gait patterns of neurologically healthy adults do not necessarily result in the faster gait speeds for individuals with chronic stroke.
Gait Posture 2004 Oct
PMID:Magnitude and pattern of 3D kinematic and kinetic gait profiles in persons with stroke: relationship to walking speed. 1533 83

The aim of this study was to analyze the changes in the standing center of pressure (COP) in a hemiplegic adult population at the beginning and the end of in-patient rehabilitation. The trajectory of the COP was recorded on a force platform and was analyzed in terms of the frequency spectra of the center of gravity (COG), and the frequency spectra of the COP minus COG, a derived measure of neuromuscular stiffness. The study population consisted of eight hemiplegic subjects, median age of 53.5 years (range 27-79 years). The median interval between stroke and the first series of measures was 31 days (range 4-127) and the median interval between the two measures was 47.5 days (range 12-92). All the subjects were treated in an inpatient setting in a Neurorehabilitation Center. Our results showed that following rehabilitation, there was a reduction in the amplitude of the medio-lateral frequency spectra of the COP from a median of 5.651 mm (range 3.13-14.05) at the first measurement to 4.408 mm (range 2.40-8.58) at the second measurement. These changes were significant (p<0.05). Significant changes were also observed in the measure of COP minus COG, from 1.324 mm (range 0.92-2.63) on the first measure to 0.917 mm (range 0.46-1.53) on the second measure. In conclusion, the medio-lateral COP trajectory of hemiplegic subjects significantly improved during rehabilitation. We hypothesized that a major component of this improvement was the decrease in neuromuscular stiffness of the adductor and abductor muscles of the hips.
Gait Posture 2005 Jun
PMID:Changes in the standing posture of stroke patients during rehabilitation. 1588 30


1 2 3 4 5 6 7 8 9 10 Next >>