Visual control of locomotion in Parkinson's disease.
The effect of placing parallel lines on the walking surface on parkinsonian gait was evaluated. To identify the kind of visual cues (static or dynamic) required for the control of locomotion, we tested two visual conditions: normal lighting and stroboscopic illumination (three flashes/s), the latter acting to suppress dynamic visual cues completely. Sixteen subjects with idiopathic Parkinson's disease (nine males, seven females; mean age 68.8 years) and the same number of age-matched controls (seven males; nine females, mean age 67.5 years) were studied. During the baseline phase, Parkinson's disease patients walked with a short-stepped, slow velocity pattern. The double limb support duration was increased and the step cadence was reduced relative to normal. Under normal lighting, visual cues from the lines on the walking surface induced a significant improvement in gait velocity and stride length in Parkinson's disease patients. With stroboscopic illumination and without lines, both groups reduced their stride length and velocity but the changes were significant only in the Parkinson's disease group, indicating greater dependence on dynamic visual information. When stroboscopic light was used with stripes on the floor, the improvement in gait due to the stripes was suppressed in parkinsonian patients. These results demonstrate that the perceived motion of stripes, induced by the patient's walking, is essential to improve the gait parameters and thus favour the hypothesis of a specific visual-motor pathway which is particularly responsive to rapidly moving targets. Previous studies have proposed a cerebellar circuit, allowing the visual stimuli to by-pass the damaged basal ganglia. (+info)
Development of a 12-min treadmill walk test at a self-selected pace for the evaluation of cardiorespiratory fitness in adult men.
The direct measurement of true maximal oxygen uptake (VO2max) and oxygen uptake corresponding to anaerobic threshold (VO2AT) is not always practical, especially in middle age and older populations. Therefore, the purpose of this study was to develop a simple test that could accurately estimate cardiorespiratory fitness using a submaximal treadmill walking protocol for middle age, older, sedentary individuals and patients with chronic disease. Subjects for this study were 42 men (44.9 +/- 15.7 years), which included 17 patients with coronary heart disease (57.0 +/- 9.6 years). VO2peak and VO2AT were measured using a treadmill protocol (VO2peak; 38.4 +/- 11.6 ml/kg/min, VO2AT; 22.9 +/- 7.4 ml/kg/min). This simple test assessed the total distance covered in 12 minutes on the treadmill at an intensity corresponding to either 1) 11 on the Borg scale of ratings of perceived exertion (RPE11), 2) 13 on the Borg scale of ratings of perceived exertion (RPE13), or 3) "Optimal" by subjective judgment. The correlation coefficients between VO2peak or VO2AT and total distance at the three intensities (RPE11; 950 +/- 100 m, RPE13; 1080 +/- 140 m Optimal; 1050 +/- 110 m) were statistically significant, ranging from 0.72 to 0.85. The test-retest reliability coefficient on 12 subjects was 0.98. The oxygen uptake (VO2) was measured during the three walk tests on 15 subjects. There were no significant changes in submaximal VO2 values from min 4 to min 12 (RPE11; 19.8 +/- 4.7 ml/kg/min, RPE13; 24.1 +/- 4.9 ml/kg/min, Optimal; 23.1 +/- 4.8 ml/kg/min) in any of the three tests. Similarly, the three submaximal VO2 values did not differ from the VO2AT value (21.2 +/- 8.3 ml/kg/min) obtained in the initial maximal test. These results suggest that the 12-min submaximal treadmill walk test (STWT) is a valid method for the assessment of VO2peak and VO2AT. Therefore, the STWT could be a useful performance test for evaluating cardiorespiratory fitness in middle age, older, sedentary individuals and patients with chronic disease. (+info)
Maturation of gait dynamics: stride-to-stride variability and its temporal organization in children.
In very young children, immature control of posture and gait results in unsteady locomotion. In children of approximately 3 yr of age, gait appears relatively mature; however, it is unknown whether the dynamics of walking change beyond this age. Because stride dynamics depend on neural control, we hypothesized that motor control would continue to develop beyond age 3. To test this hypothesis, we measured the gait cycle duration on a stride-by-stride basis in 50 healthy 3- to 14-yr-old children (25 girls). Measurements of stride-to-stride variability were significantly larger both in the 3- and 4-yr-old children, compared with the 6- and 7-yr-old children, and in the 6- and 7-yr-old children, compared with the 11- to 14-yr-old children. Measurements of the temporal organization of gait also revealed significant age-dependent changes. The effects of age persisted even after adjusting for height. These findings indicate that mature stride dynamics may not be completely developed even in healthy 7-yr-old children and that different aspects of stride dynamics mature at different ages. (+info)
A clinical guide to assess the role of lower limb extensor overactivity in hemiplegic gait disorders.
BACKGROUND AND PURPOSE: The aim of this study was to assess the role of knee and ankle extensor overactivity in the hemiplegic gait observed in stroke victims and to propose a clinical guide for selecting patients before treatment of a supposed disabling spasticity. METHODS: A standardized physical examination procedure was performed in 135 consecutive stroke patients. All patients were able to walk without human assistance. The period after stroke ranged from 3 to 24 months (mean, 11.5+/-7.25 months). Spasticity was evaluated with the stroke victim in sitting position and during walking. Overactivity of the quadriceps was considered disabling when inducing inability to flex the knee during the swing phase despite adequate control of knee flexion in sitting and standing positions; overactivity of the triceps surae was considered to be disabling when heel strike was not possible despite good control of the ankle flexion in sitting position; triceps retraction was also considered. RESULTS: Disabling overactivity was observed in 56 (41.5%) patients: 11 times for the quadriceps femoris, 21 times for the triceps surae, and 21 times for both muscles. It was considered to be the main disorder impairing gait among only 16 (12%) patients: 9 for the quadriceps alone, 3 for the triceps alone, and 4 for both. Sitting spasticity of the lower limb was not predictive of disabling overactivity during walking. CONCLUSIONS: Extensor muscle overactivity is one of the components of gait disorders in stroke patients. The difficulty in assessing spasticity and its real causal effect in gait disturbances are discussed. A clinical guide is proposed. (+info)
Standard osteopathic manipulative treatment acutely improves gait performance in patients with Parkinson's disease.
Patients with Parkinson's disease exhibit a variety of motor deficits which can ultimately result in complete disability. The primary objective of this study was to quantitatively evaluate the effect of osteopathic manipulative treatment (OMT) on the gait of patients with Parkinson's disease. Ten patients with idiopathic Parkinson's disease and a group of eight age-matched normal control subjects were subjected to an analysis of gait before and after a single session of an OMT protocol. A separate group of 10 patients with Parkinson's disease was given a sham-control procedure and tested in the same manner. In the treated group of patients with Parkinson's disease, statistically significant increases were observed in stride length, cadence, and the maximum velocities of upper and lower extremities after treatment. There were no significant differences observed in the control groups. The data demonstrate that a single session of an OMT protocol has an immediate impact on Parkinsonian gait. Osteopathic manipulation may be an effective physical treatment method in the management of movement deficits in patients with Parkinson's disease. (+info)
Relationship of lesion location to clinical outcome following microelectrode-guided pallidotomy for Parkinson's disease.
The purpose of this study was to examine the relationship between lesion location and clinical outcome following globus pallidus internus (GPi) pallidotomy for advanced Parkinson's disease. Thirty-three patients were prospectively studied with extensive neurological examinations before and at 6 and 12 months following microelectrode-guided pallidotomy. Lesion location was characterized using volumetric MRI. The position of lesions within the posteroventral region of the GPi was measured, from anteromedial to posterolateral along an axis parallel to the internal capsule. To relate lesion position to clinical outcome, hierarchical multiple regression analysis was used. The variance in outcome measures that was related to preoperative scores and lesion volume was first calculated, and then the remaining variance attributable to lesion location was determined. Lesion location along the anteromedial-to-posterolateral axis within the GPi influenced the variance in total score on the Unified Parkinson's Disease Rating Scale in the postoperative 'off' period, and in 'on' period dyskinesia scores. Within the posteroventral GPi, anteromedial lesions were associated with greater improvement in 'off' period contralateral rigidity and 'on' period dyskinesia, whereas more centrally located lesions correlated with better postoperative scores of contralateral akinesia and postural instability/gait disturbance. Improvement in contralateral tremor was weakly related to lesion location, being greater with posterolateral lesions. We conclude that improvement in specific motor signs in Parkinson's disease following pallidotomy is related to lesion position within the posteroventral GPi. These findings are consistent with the known segregated but parallel organization of specific motor circuits in the basal ganglia, and may explain the variability in clinical outcome after pallidotomy and therefore have important therapeutic implications. (+info)
Reassessment of unilateral pallidotomy in Parkinson's disease. A 2-year follow-up study.
Unilateral pallidotomy has gained popularity in treating the motor symptoms of Parkinson's disease. We present the results of a 2-year post-pallidotomy follow-up study. Using the Unified Parkinson's Disease Rating Scale (UPDRS), the Goetz dyskinesia scale and the Purdue Pegboard Test (PPBT), we evaluated 20 patients at regular intervals both off and on medications for 2 years post-pallidotomy. There were no significant changes in the dosages of antiparkinsonian medications from 3 months pre-pallidotomy to 2 years post-pallidotomy. On the side contralateral to the operation, the improvements were preserved in 'on'-state dyskinesia (83% reduction from pre-pallidotomy to 2 years post-pallidotomy, P < 0.001) and 'off'-state tremor (90% reduction from pre-pallidotomy to 2 years post-pallidotomy, P = 0.005). There were no statistically significant differences between pre-pallidotomy scores and those at 2 years post-pallidotomy in ipsilateral dyskinesia, axial dyskinesia, 'off'- or 'on'-state PPBT, 'off'-state Activities of Daily Living (ADL) and 'off'-state gait and postural stability. After 2 years, the 'on'-state ADL scores worsened by 75%, compared with pre-pallidotomy (P = 0.005). We conclude that 2 years after pallidotomy, the improvements in dyskinesia and tremor on the side contralateral to pallidotomy are preserved, while the initial improvements in most other deficits disappear, either because of progression of pathology or loss of the early efficacy achieved by surgery. (+info)
Impaired modulation of quadriceps tendon jerk reflex during spastic gait: differences between spinal and cerebral lesions.
In healthy subjects, functionally appropriate modulation of short latency leg muscle reflexes occurs during gait. This modulation has been ascribed, in part, to changes in presynaptic inhibition of Ia afferents. The changes in modulation of quadriceps tendon jerk reflexes during gait of healthy subjects were compared with those of hemi- or paraparetic spastic patients. The spasticity was due to unilateral cerebral infarction or traumatic spinal cord injury, respectively. The modulation of the quadriceps femoris tendon jerk reflex at 16 phases of the step cycle was studied. The reflex responses obtained during treadmill walking were compared with control values obtained during gait-mimicking standing postures with corresponding levels of voluntary muscle contraction and knee angles. In healthy subjects the size of the reflexes was profoundly modulated and was generally depressed throughout the step cycle. In patients with spinal lesion the reflex depression during gait was almost removed and was associated with weak or no modulation during the step cycle. In patients with cerebral lesion there was less depression of the reflex size associated with a reduced reflex modulation on the affected side compared with healthy subjects. On the 'unaffected' side of these patients reflex modulation was similar to that of healthy subjects, but the reflex size during gait was not significantly different from standing control values. These observations suggest that the mechanisms responsible for the depression of reflex size and the modulation normally seen during gait in healthy subjects are impaired to different extents in spasticity of spinal or cerebral origin, possibly due to the unilateral preservation of fibre tracts in hemiparesis. (+info)