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Biomedical subjects

R D Staton

Publications and source records attributed to R D Staton.

At least 19 recordsLinked to original sources
PubMed1990

Performance of children with ADHD on tests sensitive to frontal lobe dysfunction.

The performances of 20 children with attention deficit hyperactivity disorder (ADHD) were compared with those of 20 matched normal controls on a battery of neuropsychological tests. The ADHD children exhibited impaired function in reading comprehension, verbal learning and memory, and on the Information, Arithmetic, Digit Span, Block Design, and Coding subtests of the Wechsler Intelligence Scale for Children-Revised, but they performed nearly normally on measures of verbal and design fluency and on the Wisconsin Card Sorting Test. The hypothesis that disturbances in frontal lobe function related to impulse control may be responsible for the cognitive impairments observed in ADHD was not supported. Inability to control and direct attention appears to be more central to the pathophysiology of this disorder.

Attention↗
PubMed1989

A pilot controlled study of the use of imipramine to reduce myotonia.

It has been hypothesized that myotonic dystrophy is caused by a generalized disorder of membrane aminergic and petidergic receptors. A single uncontrolled study has suggested that the affective symptomatology and muscular disability of this disorder might be improved by tricyclic antidepressant treatment. In the present study, 12 adult patients with myotonic dystrophy (age range 18-55 yr) were treated with imipramine and placebo in a double-blind crossover paradigm. Both grip and percussion myotonia were significantly improved by imipramine treatment independent of change in depressive symptomatology. Serum drug levels revealed nonlinear elimination kinetics for imipramine in this patient population.

Adult↗
PubMed1988

The electroencephalographic pattern during electroconvulsive therapy: V. Observations on the origins of phase III delta energy and the mechanism of action of ECT.

The generation of the spike-wave activity of Phase III of ECT seizures is attributed to the recurrence of synchronized, prolonged periods of intense inhibitory current flow (hyperpolarization), and associated rebound spike bursts, produced by the inhibitory circuit relationships and intrinsic electrophysiological properties of thalamic neurons. An anatomical and neurophysiological model of the development of generalized, synchronous 3-Hz spike-wave seizure activity is proposed which outlines the origin, maintenance, slowing, and termination of this fundamental seizure rhythm. Phase III inhibitory current flow (delta energy) and/or spike bursts may bring about therapeutic benefit by initiating a chain of agonist-independent and agonist-dependent events which results in long-term augmentation of serotonergic and noradrenergic neurotransmission and diminution of cholinergic neurotransmission in the forebrain. A specific anatomical and functional model of the mechanism of action of ECT is proposed, in which: (1) adrenergic and cholinergic pathways in the forebrain are assumed to be massively stimulated during ECT seizures, whereas serotonergic pathways are assumed to be inhibited during these seizures; (2) the beneficial effects of ECT are considered to be more dependent upon ECT-induced changes in 5-HT neurotransmission than upon alteration of noradrenergic function; (3) these beneficial effects involve up-regulation of 5-HT2 and down-regulation of M1- and M2-muscarinic receptor densities by both agonist-independent and agonist-dependent mechanisms, coupled with functional augmentation of noradrenergic neurotransmission; and (4) these effects may be brought about by Phase III inhibitory current flow- and/or spike burst-induced alteration of the function of second-messenger generator systems.

Delta Rhythm↗
PubMed1986

The electroencephalographic pattern during electroconvulsive therapy. III. Analysis of frontotemporal and nasopharyngeal spectral energy.

This study analyzes the frontotemporal and nasopharyngeal spectral energy of an ECT-induced seizure, in order to investigate the origin of the final Phase III activity, which contains most of the seizure's energy. Data supports these findings: energy in the delta frequency band is responsible for the generation, propagation, and maintenance of Phase III of the ECT-induced seizure; the synchronous "delta-firing" depolarizations of Phase III are recurrently initiated by an ECT-induced "generator" process; higher magnitudes of energy are generated centrally than are generated laterally during Phase III; and the lessened memory impairment associated with nondominant unilateral ECT is attributable to the markedly lower peak and total energies observed in the unstimulated temporal lobe.

Brain↗
PubMed1986

The electroencephalographic pattern during electroconvulsive therapy. IV. Spectral energy distributions with methohexital, innovar and ketamine anesthesias.

During Phase III of nondominant unilateral ECT seizures, total energy, total peak energy, total delta energy, and 1/2-power duration of total delta energy are all less (shorter) in the unstimulated, dominant hemisphere than they are in the stimulated hemisphere. Interhemispheric differences in total energy are greatest in the lateral frontotemporal cortex, where they average 40 percent with both methohexital and ketamine anesthesias in F8 greater than F7 and T4 greater than T3. This circumstance probably explains the characteristic memory sparing associated with nondominant unilateral ECT. The magnitudes of total and peak energies in each frequency band decrease in the order: delta greater than theta greater than alpha greater than beta. Delta energy constitutes approximately three-fourths of the unilateral ECT seizure's total energy, and Phase III delta energy may be the therapeutically effective agent in this treatment. Seizures induced during ketamine anesthesia are associated with a higher percentage of delta energy, with higher magnitudes of total energy and of total and peak delta energy, and with longer 1/2-power durations of delta energy. Nondominant unilateral ECT with ketamine anesthesia offers promise as the treatment of choice for patients resistant to ECT administered with methohexital anesthesia.

Anesthetics↗
PubMed1985

Antidepressant treatment of children: clinical relapse is unrelated to tricyclic plasma concentrations.

Plasma concentrations of imipramine and amitriptyline and their desmethylated metabolites were measured in 20 children being treated for major depressive illness 2 wk. and 5 to 10 wk. after achieving drug dosages of 2.25 mg/kg body weight. At 2 wk. all children had exhibited clinical improvement, but by 10 wk. 4 of the 10 children treated with imipramine and 5 of the 10 children treated with amitriptyline had experienced clinical relapse of depressive symptoms. Tricyclic antidepressant plasma concentrations and ratios were comparable in the subgroups of children who maintained their clinical improvement and those who relapsed. There was no evidence of a systematic decline in plasma tricyclic antidepressant concentrations in those children who relapsed.

Adolescent↗
PubMed1982

Right hemisphere involvement in learning disability, attention deficit disorder, and childhood major depressive disorder.

Learning disability, attentional disorder and childhood major depression are frequent diagnoses in children with behavioral disturbances and impaired school performance. All three disorders are associated with right cerebral hemisphere dysfunction. Anatomical disturbance of right hemisphere function results in learning disability and/or attentional disorder. The physiological disturbance of right hemisphere function produced by a major depressive episode results in additional learning disability and/or attentional disorder.

Attention↗
PubMed1982

Reduplicative paramnesia: a disconnection syndrome of memory.

A case of post-traumatic reduplicative paramnesia (Capgras syndrome) is presented in which the patient experiences duplications in all three spheres of orientation (time, place, person). We postulate that these duplications are the result of a disconnection of new memory registration from past memory stores. The patient is unable to integrate present cues with premorbid experience, and bases judgments of his present orientation upon recollections from the past. A deep lesion at the right posterior hippocampus and temporo-parieto-occipital junction is suggested as the site of this postulated primary memory disconnection, based upon neuropsychological testing and CAT scan results. This right temporal atrophy and memory disconnection appears to have induced immature personality changes.

Adult↗
PubMed1982

The electroencephalographic pattern during electroconvulsive therapy II. Preliminary analysis of spectral energy.

Computer assisted energy-spectral analyses were obtained on EEG recordings of unilateral non-dominant hemisphere ECT-induced seizures using the different pre-ECT anesthetic agents methohexital (Brevital), Innovar, and ketamine (Ketalar). The previously postulated predominance of electrical energy over the stimulated (right) hemisphere early in ECT-induced seizures is confirmed. There appears to be marked reduction in total seizure energy with methohexital anesthesia, whereas ketamine anesthesia appears to be associated with increased overall seizure energy. The greatest right to left energy transfer during the seizure occurred with Innovar anesthesia.

Adult↗