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PubMed1994

Electrophysiological investigation of thalamic neuronal mechanisms of motor disorders in parkinsonism: an influence of D2ergic transmission blockade on excitation and inhibition of relay neurons in motor thalamic nuclei of cat.

In acute experiments on cats anaesthetized with ketamine (25 mg/kg, i.m.) and immobilized with myorelaxine (2 mg/kg, i.v.) the activity of two groups of motor thalamic (nucleus ventralis anterior thalami-nucleus ventralis lateralis thalami) relay neurons was studied. The neurons (n = 7) receiving afferents from deep cerebellar nuclei and projecting to the motor area 4 gamma were included in the first group, and those (n = 12) receiving afferents from nucleus entopeduncularis and projecting to the supplementary motor area 6 were included in the second one. All changes in the background activity and reactions to cerebellothalamic or nucleus entopeduncularis stimulation developing under the influence of D2 receptor antagonist haloperidol (1.5-1.7 mg/kg, i.v.) have been studied in the same cell. Under haloperidol influence both groups of neurons showed a reliable decrease of background activity and generation of high frequency discharges accompanied by a shift in the mode of interspike interval histograms. A regular decrease of probability and increase of response latencies after stimulation of afferent input were observed in neurons receiving afferents from the cerebellum. In nucleus ventralis anterior thalami-nucleus ventralis lateralis thalami neurons with an inhibitory input from nucleus entopeduncularis, a shortening of inhibition from 17.5 +/- 3.6 to 9.1 +/- 1.8 ms (P < 0.05) under the haloperidol influence was evident. If the inhibition evoked by nucleus entopeduncularis stimulation consisted of two phases separated by a period of excitation (n = 4), the duration of the second phase of inhibition after haloperidol injection regularly increased and the excitation separating the phase of inhibition after haloperidol injection regularly increased and the excitation separating the phases of inhibition became more prominent. Observation on the spontaneous activity and reactions of the same neuron for 2 h or more showed a gradual moderation of the changes evoked by haloperidol. On the basis of data obtained it is concluded that the blockade of D2 receptors is followed by the increase of inhibitory processes in the relay neurons of motor thalamic nuclei. The suggestion is discussed that during the blockade of D2 receptors afferent impulsation to the motor cortex is being restricted and its influence on segmental apparatus of the spinal cord decreases. These conditions are beneficial for the development of spasticity (rigidity). At the same time, hyperpolarization of the relay neurons promotes the development of oscillatory processes at least in part of them and creates conditions for forming of tremor generators.

Action Potentials↗
PubMed1994

Prolonged warm ischemia and limb survival: case report.

A 21-year-old woman sustained a supracondylar crush injury of her arm. The extremity underwent severe ischemia for more than 16 hours after an unsuccessful brachial artery repair. The forearm muscles became rigid and the fingers could not be extended passively. Clinically these findings were felt to be similar to rigor mortis. Despite this dismal picture, secondary revascularization resulted in a highly functional hand with no loss of digits. Desperate attempts at revascularization in isolated extremity injury may be successful, despite prolonged warm ischemia time.

Adult↗
PubMed1976

Neuromyotonia: an unusual presentation of intrathoracic malignancy.

A 48 year old woman is described who presented with increasing muscular rigidity and who was found to have a mediastinal tumour. Electrophysiological studies revealed that the muscular stiffness resulted from very high frequency motor unit activity which outlasted voluntary effort, and which was abolished by nerve block. The abnormal activity may have arisen at the anterior horn cell level. Marked improvement followed the administration of diphenylhydantoin.

Anterior Horn Cells↗
PubMed1999

Dimensionality of parkinsonian signs in aging and Alzheimer's disease.

BACKGROUND: Parkinsonian signs are commonly found on the neurologic examination of older persons and are associated with morbidity and mortality. The extent to which parkinsonian signs in aging and Alzheimer's disease cluster in groups typical of Parkinson's disease has not been investigated previously. METHODS: The motor portion of the Unified Parkinson's Disease Rating Scale (UPDRS), or a version with minor modifications, was administered to more than 2,800 persons in three cohorts: (a) 637 older persons with a wide range of neurologic conditions participating in the Chicago Health and Aging Project, a study of common health problems of a random sample of older persons from a geographically defined biracial community population; (b) 638 relatively healthy and highly educated older persons from 25 Catholic religious communities participating in the Religious Orders Study, a longitudinal clinical-pathologic study of aging; and (c) 1,546 older persons undergoing evaluation for possible dementia at the Rush Alzheimer's Disease Center, an urban, tertiary care center that evaluates persons for possible dementia. Separate factor analyses were performed on each data set. Additional analyses examined the factor structure in subsets by gender and race. RESULTS: A similar grouping of items emerged in each cohort and did not differ substantially by gender or race. The factors corresponded closely with the traditional grouping of parkinsonian signs into bradykinesia, gait disturbance, rigidity, and tremor. CONCLUSIONS: The grouping of parkinsonian signs is consistent in diverse samples of older persons and does not vary substantially across gender or race. The results provide an empirical basis for summarizing the principal motoric manifestations of parkinsonism.

Aged↗
PubMed1976

Parkinsonian akinesia, rigidity and tremor in the monkey. Histopathological and neuropharmacological study.

Parkinsonian postural tremor and rigidity most likely involve the disruption of the dopaminergic (DA) nigrostriatal mechanisms and the corresponding rubro-olivo-cerebello-rubral loop without excluding the involvement of related dentato-rubral and dentato-thalamic nervous fascicles. The integrity of the magnocellular division of the red nucleus and of the rubrotegmentospinal pathway, however, is apparently essential for the expression of rigidity. Akinesia most likely results from the bilateral involvement of brain stem catecholaminergic (CA) mechanisms including the DA nigrostriatal pathways. Finally the integrity of the pallidothalamic fibers seems to represent an essential feature for the improvement of these motor disorders by DA agonists, suggesting that certain of these agents, such as apomorphine, exert their main effects through the neostriatal DA receptors.

Animals↗
PubMed1993

Reversal of rigidity and improvement in motor performance by subthalamic high-frequency stimulation in MPTP-treated monkeys.

In Parkinson's disease the loss of dopaminergic neurons in the substantia nigra is associated with global disorganization of basal ganglia activity and, in particular, with increased activity of the excitatory glutamatergic neurons of the subthalamic nucleus. Recent experimental studies have shown that parkinsonian symptoms can be alleviated by selective lesioning of the subthalamic nucleus in monkeys treated with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). We measured the effect of high-frequency stimulation of the subthalamic nucleus in two unilaterally MPTP-treated monkeys in order to determine whether it was possible to obtain reversible, gradual and controllable functional impairment of this structure. Clinical, mechanographic and electromyographic results demonstrate that this technique can alleviate parkinsonian rigidity and bradykinesia without causing dyskinesia or hemiballismus. This study supports the hypothesis that the subthalamic nucleus and its excitatory projections have an important role in the mechanisms sustaining the expression of parkinsonian motor changes, and suggests that high-frequency stimulation of the subthalamic nucleus could be included in treatment for parkinsonism.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed2005

Bilateral subthalamic nucleus stimulation improves balance control in Parkinson's disease.

BACKGROUND: Parkinson's disease (PD), the most common basal ganglia degenerative disease, affects balance control, especially when patients change balance strategy during postural tasks. Bilateral chronic stimulation of the subthalamic nucleus (STN) is therapeutically useful in advanced PD, and reduces the motor signs of patients. Nevertheless, the effects of STN stimulation on postural control are still debatable. AIMS: To assess the impact of bilateral STN stimulation on balance control in PD and to determine how basal ganglia related sensorimotor modifications act on neurosensorial organisation of balance and motor postural programming. METHODS: Twelve subjects aged 45-70 years underwent unified Parkinson's disease rating scale motor (part III) clinical tests, static and dynamic posturography, including sensory organisation and adaptation tests, shortly before and six months after bilateral implantation of electrodes into the STN. RESULTS: The postoperative static test showed an improvement in postural control precision both in eyes open and eyes closed conditions. The dynamic test highlighted the decreased number of falls and the ability of the patients to develop more appropriate sensorimotor strategies when stimulated. The sensory organisation test showed an improvement of equilibrium score and, thus, a better resolution of sensorial conflicts. CONCLUSIONS: STN stimulation allowed a reduction in rigidity and therefore an improvement in the ability to use muscular proprioception as reliable information, resulting in vestibulo-proprioceptive conflict suppression. STN stimulation has a synergistic effect with levodopa for postural control. Accordingly, non-dopaminergic pathways could be involved in postural regulation and STN stimulation may influence the functioning of these pathways.

Aged↗
PubMed1985

Effect of clorazepate in spasticity and rigidity: a quantitative study of reflexes and plasma concentrations.

The effect on increased myotatic reflexes of desmethyldiazepam, formed from its precursor clorazepate, was assessed in a double-blind cross-over study of 27 days duration. Eight patients with spasticity or rigidity were given placebo or active substance; first in loading doses for 2 days, then 5 mg every 12 h for a total of 10 days. A wash-out period of 7 days was interposed between the 2 10-day periods. Desmethyldiazepam had a normalizing effect on the increased phasic ankle reflexes seen in spasticity, but not on the increased tonic reflex seen in rigidity. The mean concentration of desmethyldiazepam in the steady state was 1227 nmol/l (range 600-1990 nmol/l). The plasma concentration of desmethyldiazepam tended to correlate with the percent decrease in phasic reflex activity (P = 0.08, 2-tailed). A slight drowsiness in 2 patients was the only side-effect seen. In conclusion, desmethyldiazepam given as clorazepate seems to be a suitable medicament in the treatment of spasticity.

Adult↗
PubMed1979

Spinal internuncial neurones in progressive encephalomyelitis with rigidity.

The clinical and pathological features of a fourth patient with progressive encephalomyelitis with rigidity are reported and compared with those previously described. It is suggested that the muscular rigidity, abnormal postures, painful muscular spasms, and myoclonus are a product of excessive and abnormal discharges of alpha motor neurones caused by their release from control by spinal internuncial neurones. A count of neuronal perikarya in the ventral horns confirmed that the disease selectively destroyed small and medium sized neurones, most of which were spinal internuncial neurones. Experimental, clinical, and pathological evidence concerning spinal internuncial neurones is reviewed and found to conform to this theory. The pathogenesis of opsoclonus may be similar.

Astrocytes↗
PubMed1984

[Cervico-mimetic meningeal symptom in acute diffuse lesions of the cerebral meninges].

The response of a patient in the form of a painful grimace at the examination of occipital rigidity is considered as an objective positive cervical-mimic symptom. Its informative value increases when diffuse muscular hypertonus and restlessness compound the study and interpretation of the major classic meningeal symptoms. In seven patients, a positive symptom made it possible to connect their state with acute diffuse meningeal pathology prior to a cerebrospinal fluid examination; a negative symptom allowed the exclusion of meningeal pathology in 13 patients which was confirmed by CSF examination. The author failed to find any reported data on this symptom.

Acute Disease↗
PubMedDate not supplied

[Characterization of the DURR (dynamic urethral resistance relation] in the study of function lower urinary tract symptoms in the male].

OBJECTIVES: To determine the type and to quantify the DURR phenomena in the male. METHODS: We conducted a clinical and urodynamic study in 31 male patients with functional lower urinary tract symptoms. RESULTS: DURR is produced by two types of mechanisms: urethral rigidity and contraction of the urethral wall. The patients with DURR produced by rigidity showed a higher score for irritative urinary symptoms. The patient with DURR produced by the contraction of the urethral wall had greater urodynamic consequences (increased opening pressure and PURR curve). The obstructive urinary symptoms were more intense when the DURR presented in the second phase of voiding (after reaching the maximum flow). CONCLUSIONS: The DURR phenomena have clinical and urodynamic consequences in males with functional lower urinary tract symptoms; therefore their type and quantity should be adequately determined.

Adult↗
PubMed1986

[Acute neurologic dysfunction associated with a hypodensity of the basal ganglia].

A previously healthy five years old boy, following a mild nonspecific upper respiratory infection developed, fever (39 degrees C), vomiting, clouding of consciousness and focal seizures. The CSF showed a mononuclear cell reaction with negative bacterial and viral cultures. A cranial CT scan on the 4th day of admission showed bilateral low density lesions on the basal ganglia region. After 30 days of severe involvement of muscle tone (rigidity) which kept the patient immobilized in bed and without a meaningful communication with his surroundings, improvement was noticed. A repeated CT scan 40 days after admission, was considered normal. Two months after the beginning of disease, patient's physical examination was normal. This case shows striking clinical and radiological similarities to the ones described by Aicardi and Goutieres in 1982 and most likely is explained by bilateral basal ganglia edema complicating viral encephalitis. Mumps virus, being so far, the most commonly implicated.

Basal Ganglia Diseases↗
PubMed1975

Treatment of parkinsonism with l-dopa and a decarboxylase inhibitor. An electrophysiological and clinical study.

Twelve parkinsonian patients with an unsatisfactory therapeutic result on L-Dopa alone due to nausea, vomiting and involuntary movements were treated WITH L-Dopa and decarboxylase inhibitor. The daily dose reached 800mg L-Dopa and 200 mg decarboxylase inhibitor. Single doses of each of the components were also given. Electrophysiological examination of hypokinesia, tremor and rigidity, and clinical observation revealed clear evidence of rapid improvement on small doses of L-Dopa combined with decarboxylase inhibitor. Most of the improvement occurred during the 1st week before the maximal dose was reached. A single oral dose of decarboxylase inhibitor resulted in an improvement, suggesting the presence in the organism of a small AMOUNT OF L-Dopa. This work also shows the absence of liver toxicity of the drug used. Elimination of the extracerebral side effects nausea and vomiting in our opinion is a principle advantage of the compound compared to L-Dopa alone, wheras abnormal involuntary movements, which were found in all patients, remain the limiting adverse side effect.

Aged↗
PubMed1987

Rigidity and dorsiflexion of the neck in progressive supranuclear palsy and the interstitial nucleus of Cajal.

Rigidity and dorsiflexion of the neck are typical signs in progressive supranuclear palsy, but the responsible areas in the brain are unknown. To examine whether bilateral lesions of the interstitial nucleus of Cajal (INC) in the midbrain tegmentum contribute to the signs of patients with progressive supranuclear palsy, we have made bilateral INC lesions in cats and tried to correlate these studies with clinical and pathological data, including our case of progressive supranuclear palsy. Bilateral INC lesioned cats showed dorsiflexion of the neck and impairment of vertical eye movement, similar to progressive supranuclear palsy patients. Analysis of the previous clinical-pathological studies and our case have shown that dorsiflexion of the neck in progressive supranuclear palsy patients was correlated more with INC lesions than lesions of the basal ganglia.

Aged↗
PubMed1988

Comparative study of neurological and myxoedematous cretinism associated with severe iodine deficiency.

The clinical and biochemical features of myxoedematous and neurological cretinism were studied in an endemic goitre area in Algeria (goitre prevalence 51.3%; endemic cretinism 1.1%; mean urinary iodine level 127.6 nmol/l). When comparing the data collected in six different villages of the area, significant negative correlations were found between the decrease in urinary iodide and iodide/thiocyanate ratio (I/SCN) and the increase in prevalences of visible goitres, endemic cretinism and transient neonatal hypothyroidism. The cretins were divided on clinical signs into two groups: myxoedematous (MC) and neurological (NC) cretinism. Differences were noted in the neurological signs and the type of deafness encountered in both types. Although some overlap did exist, proximal spasticity and rigidity were characteristic of NC. The hormonal profiles of the two groups, including TRH tests, were clearly different. The two groups were similar with regard to the percentage of palpable thyroids, the absence of antimicrosomal and anti-thyroglobulin antibodies, seropositive viral antibodies and thiocyanate concentrations in serum and urine. Thus it is unlikely that these factors have any significant aetiological role in NC. The data collected in the general population in this area and those obtained in the mothers of the myxoedematous and neurological cretins support the hypothesis that the neurological signs are the result of hypothyroxinaemia in the mothers and the fetus at different periods of pregnancy. They could be aggravated by neonatal hypothyroidism, which may be transient in NC and permanent in MC.

Adolescent↗
PubMed1994

The primate subthalamic nucleus. III. Changes in motor behavior and neuronal activity in the internal pallidum induced by subthalamic inactivation in the MPTP model of parkinsonism.

1. The effects of reversible and irreversible pharmacological manipulations of the neuronal activity in the subthalamic nucleus (STN) on parkinsonian motor signs and neuronal activity in the internal segment of the globus pallidus (GPi) were studied in African green monkeys rendered parkinsonian by treatment with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine. 2. Muscimol injections (< or = 1 microliter, 1 microgram/microliter) into STN reduced neuronal activity recorded at the injection site within minutes. This was immediately followed by reduced akinesia, tremor, and rigidity, as well as the emergence of dyskinesias in contralateral limbs. The motor effects were accompanied by generalized behavioral activation, lasted between 10 and 60 min, and were strongly dependent on the site of injection, with injections into the lateral "arm area" of STN first affecting contralateral arm movements and injections into the "leg" area affecting leg movements first. 3. Bicuculline injections (< or = 1 microliter, 1 microgram/microliter) into STN marginally increased the neuronal activity and induced neuronal discharge in bursts. Rigidity, akinesia, and tremor in the contralateral limbs were not changed. 4. Injections of ibotenic acid in two animals (2 and 7 microliters, 10 micrograms/microliters) resulted in 70 and 51% destruction of STN, respectively. Similarly to the muscimol injections, this resulted in a reduction of the neuronal activity, a reversal of parkinsonian motor signs, and the development of dyskinesias in the contralateral limbs. 5. Although tremor was significantly reduced after STN lesions, periodic oscillatory neuronal activity in GPi persisted. The strength of modulation of the neuronal oscillation was not significantly changed after STN lesion. 6. The percentage of cells in GPi exhibiting increases in discharge in response to torque application was significantly reduced after STN lesion. The magnitude and duration of the responses with increase in firing rate were reduced after STN lesioning. 7. These results support the hypothesis that abnormally increased tonic and phasic activity in STN leads to abnormal GPi activity and is a major factor in the development of parkinsonian motor signs. Furthermore they imply that cells in the basal ganglia have the intrinsic property of discharging in periodic bursts, which is unmasked under parkinsonian conditions.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed2001

Pathophysiology of bradykinesia in Parkinson's disease.

Bradykinesia means slowness of movement and is one of the cardinal manifestations of Parkinson's disease. Weakness, tremor and rigidity may contribute to but do not fully explain bradykinesia. We argue that bradykinesia results from a failure of basal ganglia output to reinforce the cortical mechanisms that prepare and execute the commands to move. The cortical deficit is most apparent in midline motor areas. This leads to particular difficulty with self-paced movements, prolonged reaction times and abnormal pre-movement EEG activity. Movements are often performed with normally timed EMG bursts but the amount of EMG activity is underscaled relative to the desired movement parameters. There are also abnormalities in sensory scaling and sensorimotor integration. The brain appears to be able to compensate to some degree for the basal ganglia deficit. There is overactivity in the lateral premotor areas during task performance and movements can be speeded by giving sensory cues. Attention to movement is also beneficial. However, we propose that the engagement of compensatory processes may also lead to reduced performance in other tasks. For example, patients' problems in performing more than one task at the same time could result from lack of sufficient resources both to compensate for their basal ganglia deficit and to run two tasks simultaneously. Surgical therapies are unlikely to work solely by normalizing basal ganglia output to that seen in healthy individuals. It seems more plausible that surgery removes an interfering signal that allows more efficient compensation by other structures.

Animals↗
PubMedDate not supplied

Mechanical factors of cardiovascular risk in systemic arterial hypertension. A new sign of arterial rigidity.

UNLABELLED: ANTECEDENT: By means of sphygmokinetocardiography (SKCG) we developed and arterial rigidity index (ARI) which measure the pulse wave aortic carotid reflexion time over the left ventricular ejection time (LVET). This index, together with the pulse wave velocity (PWV) and the pulse pressure (PP) are indicators of arterial stiffness. In this paper we measured these index in 27 systemic artery hypertension. Cases (group A, GA), with and without left ventricular hypertrophy (subgroups: A1 SGA1, n = 13, and A2, SGA2, n = 14), respectively, and 28 normotensive cases (group B, GB). PROTOCOL: In two occasions: after 3 minutes of sitting position (SP) and after 3 minute of logging in an upright position (UP), blood pressure, ARI, PP, PWV (aortic-hand finger distance/aorto-hand finger pulse time) and R-IV interval (electrocardiographic R wave-left early ventricular kinetocardiography deflexion) were measured. RESULTS: Demography was similar in GA and GB. Systolic, diastolic and pulse pressure were significantly higher in GA vs GB. LVET (ms) was lower in GA vs GB in SP (268 +/- 42 vs 274 +/- 40, p < 0.001, respectively) and higher postexercise UP (280 +/- 42 vs 244 +/- 46, p < 0.001). PWV m/s were higher in SP in GA vs GB (9.8 +/- 2.8 vs 7.4 +/- 1.2, p < 0.001, respectively) and in UP (10.1 +/- 1.9 vs 7.9 +/- 9, p < 0.001, respectively). ARI was lower in UP in GA vs GB (0.48 +/- 0.3 vs 0.80 +/- 0.3, p < 0.003). Correlation index of PP vs SBP, vs DBP and vs PWV were significant in SP and in UP. Height had a significant correlation vs ARI in SP and UP (r = 0.60, p < 0.01, and r = 0.42, p < 0.05, respectively). CONCLUSION: PWV is increased in GA vs GB patients. The ARI index is lower in GA vs GB cases in post exercise. PWV and PP showed a statistical significant correlation; height vs ARI had also a significant correlation: SKCG is a new method, that uses a not commercially instrument, which should have clinical application.

Biomechanical Phenomena↗