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Biomedical subjects

J M Waltz

Publications and source records attributed to J M Waltz.

At least 19 recordsLinked to original sources
PubMed1997

Spinal cord stimulation: a quarter century of development and investigation. A review of its development and effectiveness in 1,336 cases.

The past two and a half decades have seen the development of a spinal cord stimulator from the early 2-electrode fixed system to the present multielectrode computerized systems. During these 25 years, spinal cord stimulation has been studied in the treatment of motor disorders. The effectiveness was studied in 1,336 cases, including cerebral palsy (456), dystonia (173), torticollis (90), multiple sclerosis (130), spinocerebellar degeneration (71), spinal cord injury (303) and posttraumatic brain injury (113). It has become increasingly evident that the maximum therapeutic effect is achieved by virtue of the applied field variables of the spinal cord level stimulated, the field configuration, its polarity, and the frequency of the stimulation. These observations have led to investigational corollaries of the therapeutic specificity of the applied field, the neurophysiologic mechanisms of these fields and the underlying abnormal neurophysiologic substrate, which may indeed be secondary to abnormalities in the nerve impulse itself.

Cerebral Palsy↗
PubMed1987

Spinal cord stimulation and motor disorders.

Spinal cord stimulation has been investigated by us during the past 10 years in the treatment of various disorders of the motor system. The effectiveness was studied in 735 cases, including cerebral palsy (212), dystonia (129), torticollis (66), spinal cord injury (169), and degenerative diseases (159). Our results indicate that in properly selected patients, stimulating the spinal neural axis is therapeutically effective in the majority of the cases treated. Our data demonstrate that the level stimulated, the pattern and the polarity of the applied field, and the frequency of the stimulation are critical to achieve a satisfactory therapeutic result and must be individualized in each patient.

Adolescent↗
PubMed1986

Spinal cord stimulation revisited: psychological effects.

97 patients undergoing spinal cord stimulation (SCS) were studied for a median of 24 days after initiation of treatment. SCS was associated with significant improvement in memory, visuo-spatial integration, activation, cognitive efficiency, attention and overall psychological status. Significant emotional improvement in self-image, anxiety and depression was also confirmed following SCS. Diagnosis did not differentially affect psychological outcome except for relief of anxiety, which was less pronounced in the case of torticollis and multiple sclerosis. The role of spinal cord modulation of behavioral activation and physiological arousal was discussed.

Adolescent↗
PubMed1985

Spinal cord stimulation in the treatment of spasmodic torticollis.

This report presents our observations in 63 patients undergoing chronic spinal cord stimulation for treatment of spasmodic torticollis. In this series there were 23 patients (36.5%) who demonstrated marked improvement, characterized by no evidence of torticollis, full range of motility of the head and neck and no pain. Moderate improvement was found in 20 patients (31.8%) who showed minimal residual torticollis, but had full motility and no pain. There were 5 patients (7.9%) considered mildly improved who demonstrated decrease in their torticollic position, spasms and pain, but retained some element of torticollis and/or some limitation of motility. Correlations were made demonstrating the effect on the results of age, sex, electrode array, the configuration of the applied field and the parameters of stimulation.

Adult↗
PubMed1985

Ventricular fluid somatostatin concentration decreases in childhood-onset dystonia.

Somatostatin was measured in CSF from individuals with a variety of neurologic diseases. In ventricular CSF, somatostatin concentration was significantly lower in individuals with childhood-onset dystonia than in individuals with other forms of dystonia or with other disorders. Severity of childhood dystonia correlated with somatostatin concentration, suggesting a progressive dysfunction of somatostatin-containing neurons with increasing disease severity. There were no significant differences in somatostatin concentration in lumbar CSF. Multiple forms of immunoreactive somatostatin were found in a pool of lumbar CSF from normal individuals. Labeled somatostatin administered intra-arterially to rats failed to cross the blood-brain barrier.

Adolescent↗
PubMed1983

Decreased ventricular fluid norepinephrine metabolite in childhood-onset dystonia.

3-methoxy-4-hydroxyphenylglycol (MHPG), the primary brain metabolite of norepinephrine (NE), was measured in ventricular fluid from 51 patients with dystonia, other movement disorders, or hydrocephalus. The dystonic patients were divided into three categories: childhood-onset form with early limb dystonia and rapid progression to generalized symptoms, more localized and benign adult-onset dystonia, and symptomatic dystonia. Patients with the childhood form had significantly lower ventricular fluid MHPG levels (8.7 +/- 0.6 ng per milliliter) than other dystonic patients (11.4 +/- 1 ng per milliliter), age-matched controls with neurologic disease (11.7 +/- 1.1 ng per milliliter), or other movement disorders (11.8 +/- 0.7 ng per milliliter). Decreased ventricular fluid MHPG levels suggest a possible abnormality of brain NE function in childhood dystonia.

Adolescent↗
PubMed1981

Free and conjugated dopamine in human ventricular fluid.

Free dopamine and an acid hydrolyzable conjugate of dopamine were measured in human ventricular fluid specimens with a radioenzymatic assay and by high performance liquid chromatography (HPLC) with electrochemical detection. Only trace amounts of free norepinephrine and dopamine were detected in ventricular fluid from patients with movement disorders. When the ventricular fluid was hydrolyzed by heating in HClO4 by lyophilization in dilute HClO4, however, a substantial amount of free dopamine was released. Values for free plus conjugated dopamine in ventricular fluid from patients who had never taken L-DOPA ranged from 139 to 340 pg/ml when determined by HPLC and from 223 to 428 pg/ml when measured radioenzymatically. The correlation coefficient for values obtained by the two methods in the same sample of CSF was 0.94 (P less than 0.001). Patients who had been treated with L-DOPA had higher levels of conjugated dopamine in their ventricular CSF which correlated inversely with the time between the last dose of L-DOPA and withdrawal of the ventricular fluid. Additionally, one patient with acute cerebral trauma had elevated levels of free norepinephrine and both free and conjugated dopamine in his ventricular fluid. Conjugation may be an important inactivation pathway for released dopamine in man.

Chromatography, High Pressure Liquid↗
PubMed1981

Multiple-lead spinal cord stimulation: technique.

This report is a continuation of our previous report on chronic spinal cord stimulation in disorders of the motor system. Improved statistics were observed following changing from the early conventional two-electrode system to a newly developed four-electrode system. The success of the four-electrode system lies in the analysis of both the electrode combinations and the frequency of stimulation. These are carried out on each patient and remain the most critical aspect of the technique. The details of the multiple lead system--the technique of implantation and protocols for carrying out electrode and frequency analysis--are presented.

Cerebral Palsy↗
PubMed1981

Multi-lead spinal cord stimulation for control of motor disorders.

This report presents observations in 160 patients undergoing chronic spinal cord stimulation for various disorders of the motor system and compares the results obtained using older conventional two-electrode bipolar stimulation with a newly developed four-electrode multiple level system. Improvement was noted in 84% of the 75 patients with cerebral palsy, 67% of the 42 patients with dystonia, 62% of the 21 patients with torticollis and 73% of the 22 patients with post-traumatic neurologic loss. Significant improvements were noted when comparing the two-electrode system with the new multiple level electrode. Marked to moderately improved patients increased from 57 to 84% in cerebral palsy, from 44 to 82% in dystonia, from 53 to 75% in torticollis and from 53 to 80% in dystonia, from 53 to 75% in torticollis and from 53 to 80% in posttraumatic neurologic conditions. There was a corresponding marked drop in unimproved patients in each condition.

Adolescent↗
PubMed1981

Multiple sclerosis. Oligodendrocyte survival and proliferation in an active established lesion.

Oligodendrocytes have been studied ultrastructurally in relationship to areas of active demyelination in multiple sclerosis. The tissue came from a central nervous system plaque sampled at biopsy during a neurosurgical procedure to correct severe intention tremor in a case of chronic progressive multiple sclerosis. Cells interpreted as oligodendrocytes were abundant within the demyelinated zone, were easily identifiable, and sometimes occurred as nests of cells suggestive of proliferation. Oligodendrocytes were also common within areas of active demyelination where numerous macrophages displayed active phagocytosis of myelin. These oligodendrocytes were paler and perhaps represented residual, surviving cells. In the relatively normal white matter adjacent to the plaque, increased numbers of oligodendrocytes occurred in association with remyelination. In the demyelinated zone, the astrocyte:macrophage:oligodendrocyte ratio was 1:2.25:4.5; within the region of ongoing demyelination, 1:4:4; and in the adjacent white matter, 1:0.1:2.1. On the basis of an apparent proliferation and survival of oligodendrocytes, the findings support the notions that there is no selective depletion of oligodendrocytes either during or shortly following central nervous system demyelination in multiple sclerosis, and that the myelin sheath is the primary target.

Adult↗
PubMed1976

Chronic cerebellar stimulation in epilepsy. Clinical and anatomical studies.

Ten of 15 patients subjected to chronic cerebellar stimulation have had previously intractable seizures modified or inhibited up to periods of three years. Stimulation of anterior lobe appears to be more efficacious than stimulation of posterior lobe. Cerebellar biopsies, obtained in five patients at the time of stimulator placement, revealed in every instance a reduction in the molecular layer, decreased or absent Purkinje cells, and decreased stellate cells. One unimproved patient died during a seizure 17 months after stimulation was initiated. Histological examination of the brain did not reveal tissue damage attributable to the stimulator. There is no evidence of any adverse effect of chronic cerebellar stimulation in humans who have undergone stimulation for periods up to three years.

Adolescent↗
PubMed1976

Chronic cerebellar stimulation in cerebral palsy.

Data are presented for the first 50 patients with cerebral palsy who underwent chronic cerebellar stimulation for symptom alleviation. We observed significant shorter and longer term improvement in spasticity as well as athetosis, speech, and functional status. Continuing increments in improvement were noted as a function of time on stimulation. In many instances, psychometric test scores and behavior also were improved. There was one death in this series. There were no neurologic complications due to cerebellar stimulation. The results of this study warrant the judicious use of cerebellar stimulation for symptomatic and functional relief in cerebral palsy.

Activities of Daily Living↗