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Biomedical subjects

P A Ahmann

Publications and source records attributed to P A Ahmann.

At least 19 recordsLinked to original sources
PubMed2001

Placebo-controlled evaluation of amphetamine mixture-dextroamphetamine salts and amphetamine salts (Adderall): efficacy rate and side effects.

OBJECTIVE: The primary objective of this study was to determine the efficacy rate of Adderall in children newly diagnosed with attention-deficit/hyperactivity disorder (ADHD). A secondary objective was to address the severity of side effects associated with Adderall treatment in children with ADHD using the Barkley Side Effects Questionnaire (BSEQ). DESIGN: Randomized, double-blind, placebo-controlled crossover trial. SETTING: A large rural tertiary care clinic. PATIENTS: Participants were prospectively recruited from children 5 to 18 years of age referred for academic and/or attention problems; 154 children who met the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria for ADHD were enrolled. Interventions. Two doses of Adderall (0.15 mg/kg/dose and 0.3 mg/kg/dose) were compared with placebo in separate 2-week trials. Participants received each dosage regimen twice daily for 7 consecutive days. MEASUREMENTS AND MAIN RESULTS: Efficacy rates were determined by comparing Adderall with placebo during the low-dose crossover sequence and also during the high-dose crossover sequence. The criteria that defined a positive response to Adderall relative to placebo (with each patient serving as their own control) included an indication of response by at least 1 of 2 parent measures of children's behavior or at least 2 of 5 teacher measures of children's behavior. The Adderall efficacy rate was determined based on parent criteria alone, teacher criteria alone, and by a more stringent definition of response that required concurrence between parent and teacher criteria. The Adderall response rate in this study ranged from 59% when requiring concurrence between parent and teacher observers, to 82% when based on parent criteria alone. Overall, 137 of 154 participants (89%) showed a positive response by either the parent or teacher response criteria. Parents completed a modified version of the BSEQ during each week of the trial. Appetite, stomachaches, and insomnia were rated as worse by parents while children were receiving either dose of Adderall; headaches were rated as worse when children were receiving the higher dose of Adderall. Parents rated certain side effects, including staring/daydreaming, sadness, euphoria, and anxious/irritable, as worse during placebo regimens. CONCLUSIONS: We found that Adderall is highly efficacious in our population of youth diagnosed with ADHD. In addition, Adderall is well-tolerated with a side effect profile similar to that reported for other psychostimulants.

Adolescent↗
PubMed1998

Tiagabine for complex partial seizures: a randomized, add-on, dose-response trial.

OBJECTIVE: To determine the efficacy and tolerability of tiagabine, a new antiepileptic drug (AED) that inhibits gamma-aminobutyric acid (GABA) uptake, at 3 dose levels vs placebo as adjunctive therapy in patients with intractable complex partial seizures (CPS). DESIGN: Randomized, double-blind, placebo-controlled study with a parallel-group, add-on design, starting with a 12-week unblinded baseline phase followed by a 20-week double-blind treatment phase. SETTING: Twenty-one US medical centers. PATIENTS: Patients (N = 297) aged 12 to 77 years, previously diagnosed as having CPS and receiving stable regimens of 1 to 3 hepatic enzyme-inducing AEDs; divalproex sodium or valproic acid was allowed in combination with any of these drugs. INTERVENTIONS: Placebo or tiagabine 4 times a day at 16, 32, or 56 mg daily. MAIN OUTCOME MEASURES: Median change in 4-week CPS frequency and adverse events. RESULTS: Median decreases in 4-week CPS frequency for the 32-mg (-2.2) and 56-mg (-2.8) tiagabine groups were significantly greater than for the placebo (-0.7) group (P = .03 and P < .03, respectively); 20% and 29% of patients in the 32- and 56-mg groups had a 50% or greater reduction in the frequency of CPS vs 4% in the placebo group (P = .002 and P < .001, respectively). Adverse effects were similar for placebo and tiagabine except for a significantly greater incidence of dizziness in the 32-mg tiagabine group, tremor in the 32- and 56-mg groups, abnormal thinking (usually mental lethargy or difficulty concentrating) in the 56-mg group, and depressed mood in the 16- and 56-mg groups. CONCLUSIONS: Tiagabine is efficacious and well tolerated as adjunctive therapy for CPS; there is a clear dose-response relationship.

Adolescent↗
PubMed1998

Stimulant use and the potential for abuse in Wisconsin as reported by school administrators and longitudinally followed children.

The purpose of this study was to describe stimulant use and abuse as reported by school administrators and children diagnosed with attention deficit/hyperactivity disorder or attention deficit disorder inattentive. Five years after being identified as Ritalin responders, 161 children were surveyed regarding stimulant use and abuse. School principals in central Wisconsin were also surveyed regarding stimulant use and policies. No child believed stimulants as prescribed could lead to abuse. Sixteen percent of the children had been approached to sell, give, or trade their medication. During school hours, 44% of children and 37% of schools reported stimulants were stored unlocked. Not all schools had written policies regarding prescription drugs, and 10% permitted students to carry their own medication. Monitoring prescription usage, periodic reassessment of efficacy, and continuing education of family and teaching staff should be part of the multimodal treatment for this disorder. School policies should be developmentally sensitive.

Administrative Personnel↗
PubMed1994

Seizure exacerbation and status epilepticus related to carbamazepine-10,11-epoxide.

Over a 3-year period, we encountered 6 adults whose seizure control unexpectedly deteriorated with the occurrence of partial status epilepticus and daily multiple seizures. Analysis of the case histories and subsequent clinical follow-up for 1 1/2 to 3 years disclosed the following evidence that demonstrates the role of carbamazepine-epoxide in the development of the seizure exacerbation: (1) There were high serum carbamazepine-epoxide concentrations while serum carbamazepine concentrations were lower than or the same as baseline levels; (2) all patients were taking drugs that are known to increase serum carbamazepine-epoxide concentrations; (3) status epilepticus failed to respond to intravenous phenytoin loading; (4) seizure exacerbation in all patients was corrected by withholding carbamazepine dose; (5) seizure exacerbation recurred in 1 patient who resumed the same dose of carbamazepine; and (6) there were no prior status epilepticus or daily multiple seizures despite previous toxicities with other antiepileptic drugs in 3 patients. Our experience shows that inconspicuous elevation of carbamazepine-epoxide levels during polytherapy may precipitate a distinct state of drug toxicity characterized by severe exacerbation of seizures. Mental retardation may be a predisposition to this condition.

Adult↗
PubMed1994

Yield of sphenoidal recording in sleep-deprived outpatients.

We retrospectively reviewed the results of sphenoidal recordings performed after sleep deprivation in 101 consecutive outpatients whose prior scalp EEGs failed to show epileptiform discharges (EDs). These patients were suspected of having seizures of temporal lobe origin. Blinded reviews of the recordings by two electroencephalographers showed a tendency for sphenoidal recording to detect EDs at a higher rate than scalp recording, but the difference did not reach statistical significance (p = 0.06). However, EDs appeared exclusively at sphenoidal electrodes in 11 patients and exclusively at scalp electrodes in 3. The probability of detecting EDs with combined scalp and sphenoidal recordings was greater when spells were characterized by focal symptoms or signs. Except in three patients, initial EDs occurred during the first 30 min of recording. We recommend that post-sleep-deprivation recording be performed initially with scalp and other noninvasive electrodes (such as anterior temporal, ear, or cheek electrodes). If no EDs occur after 30 min, sphenoidal electrode insertion and recording may then be considered, especially in patients with spells characterized by focal signs or symptoms.

Adolescent↗
PubMed1993

Prognosis of photoparoxysmal response in nonepileptic patients.

Photoparoxysmal response (PPR) is sometimes incidentally encountered in EEGs performed for evaluation of nonepileptic symptoms. We conducted the first long-term study of a cohort of nonepileptic patients to determine their risk of having seizures subsequent to incidental recording of PPR. After 6 to 12 years (mean, 9 years), none of the 33 patients had had epileptic seizures. To identify prognostic factors associated with PPR, we performed a case-control study comparing the cohort with 33 age-matched patients who had had epileptic seizures prior to PPR recording. There was no statistically significant difference between the two groups with respect to the clinical or EEG data. Morphology of the PPR discharge was not different between the two groups. Contrary to what is widely believed, persistence of PPR discharges beyond stimulation was not associated with a high risk of developing seizures. Prognosis of PPR is age-dependent and seems favorable in adults without previous epileptic seizures.

Adolescent↗
PubMed1993

Placebo-controlled evaluation of Ritalin side effects.

OBJECTIVE: To address the frequency of side effects of Ritalin therapy in children with attention deficit hyperactivity disorder (ADHD) using the Barkeley Side Effects Questionnaire (BSEQ) in a clinical setting. DESIGN: Randomized double-blind placebo-controlled cross-over trial. SETTING: A large rural tertiary care clinic. PATIENTS: 234 consecutive children aged 5 through 15 years who met the Diagnostic and Statistical Manual of Mental Disorders (3rd ed, revised) criteria for ADHD were enrolled. Of these children, 206 had sufficient side effects data for analysis. INTERVENTIONS: 0.3 mg/kg per dose and 0.5 mg/kg per dose Ritalin compared to placebo in separate 2-week trials. Each treatment was given three times a day for 7 consecutive days. MEASUREMENTS AND MAIN RESULTS: Parents, blinded to the treatment assignment, assessed side effects via the BSEQ at baseline and at the end of each of the 4 treatment weeks. Univariate odds ratios (OR) were used to describe the magnitude of differences in observed side effects between Ritalin and placebo weeks of the trial for each of the items on the BSEQ. The frequency of the following side effects significantly increased with Ritalin therapy: insomnia (OR = 3.13, 95% confidence interval [CI] = (1.80,5.42)), appetite disturbance (OR = 19.00, 95% CI = (9.18,39.31)), stomachache (OR = 7.00, 95% CI = (3.29, 14.89)), headache (OR = 5.29, 95% CI = (2.51,11.15)), and dizziness (OR = 7.50, 95% CI = (1.93,29.13)). The frequency of the following side effects significantly decreased with Ritalin therapy: staring and daydreaming (OR = 0.47, 95% CI = (0.27,0.84)), irritability (OR = 0.33, 95% CI = (0.18,0.61)), anxiety (OR = 0.42, 95% CI = (0.23,0.76)), and nailbiting (OR = 0.19, 95% CI = (0.07, 0.53)). The incidence rates of the remaining BSEQ items did not differ significantly between the Ritalin and placebo weeks of the trial. CONCLUSION: The BSEQ proved to be clinically effective in tracking Ritalin side effects and should be incorporated into the routine evaluation and monitoring of ADHD patients for whom stimulants are prescribed.

Adolescent↗
PubMed1989

Posthemorrhagic hydrocephalus in high-risk preterm infants: natural history, management, and long-term outcome.

The natural history, medical management, and outcome in infants with progressive posthemorrhagic hydrocephalus after intraventricular hemorrhage were studied prospectively. Infants with asymptomatic severe posthemorrhagic hydrocephalus were managed with a predetermined protocol. Outcome between groups at 1 to 2 years and at more than 3 years was compared. The natural history study, restricted to the inborn population, revealed that posthemorrhagic hydrocephalus developed in 53 of 409 infants with intraventricular hemorrhage. The progression of hydrocephalus either was arrested or regressed in 35 of 53 infants; progression to severe hydrocephalus occurred in 18 of 53 infants. The severe posthemorrhagic hydrocephalus was asymptomatic in 16 of 18 infants. The management and outcome study included both inborn and outborn infants. Of 50 infants, 12 had symptomatic severe hydrocephalus and 38 had asymptomatic severe hydrocephalus. The 16 infants managed with close observation were as likely to remain shunt free as the 22 infants managed with serial lumbar punctures. Of 38 infants, 20 were managed without shunts. At 3 to 6 years, the outcome of infants in the close observation group did not differ from that in the lumbar puncture group. Long-term outcome of infants with progression to asymptomatic severe hydrocephalus did not differ from that of infants in whom disease progression was arrested. Poor outcome in infants with intraventricular hemorrhage and subsequent posthemorrhagic hydrocephalus was related to severity of hemorrhage and gestational age at birth less than 30 weeks. Because long-term outcome of infants with severe hydrocephalus did not differ from that of infants in whom the progression of hydrocephalus was arrested or whose condition improved before hydrocephalus became severe, we currently attempt medical management of these infants.

Brain Damage, Chronic↗
PubMed1987

Brain death in children: characteristic common carotid arterial velocity patterns measured with pulsed Doppler ultrasound.

The clinical criteria for brain death in children remain controversial. An accepted confirmatory test for brain death is the documented absence of intracranial blood flow, the most common methods being arteriography and radionuclide cerebral angiography. We correlated the common carotid arterial blood velocity patterns measured by pulsed Doppler ultrasound in 32 brain-dead infants and children with results of their clinical examinations and, whenever possible, with radionuclide cerebral angiography. A distinct, characteristic carotid arterial blood velocity waveform indicating absent cerebral blood flow appeared in 19 of the 23 brain-dead patients 4 months of age or older. The velocity patterns of the other four older children were similar, but not identical, to the characteristic waveform. The remaining nine brain-dead patients were infants 4 months of age or younger. These infants had velocity waveforms different from those of healthy infants, but also were totally different from the characteristic brain death pattern of older children. No patient had the characteristic brain death waveform without being clinically brain dead. Measurement of carotid arterial blood velocity with pulsed Doppler ultrasound is a repeatable, noninvasive, portable test useful for confirmation of brain death in children.

Blood Flow Velocity↗
PubMed1987

Neurologic outcome following pediatric resuscitation.

This study reports the survival rate and short-term neurologic outcome of children who sustained cardiac arrests at Henrietta Egleston Hospital for Children, a pediatric teaching hospital. A commonly held belief in pediatric centers has been that children tolerate the insult of cardiac arrest better than adults. Cardiac arrest was defined as the need for external or internal cardiac compressions. Critical care nurses specially trained for this project collected the arrest data and performed the serial neurological exams. Results showed that despite a low overall survival rate, neurological outcome appears to be good after the arrest even in patients who expire prior to discharge. Major neurologic deficits, such as hemiplegia and severe developmental delay, do not occur. Nursing implications of the study, which is in its second year, are discussed.

Adolescent↗
PubMed1986

Breath amplitude modulation of heart rate variability in normal full term neonates.

The relationship between heart rate variability and respiration patterns was investigated using spectral analysis techniques in nine full-term infants whose ages ranged from 39-75 h. All the infants were studied during sleep, although no attempt was made to classify rapid eye movement or nonrapid eye movement states prospectively. The data obtained were examined to determine which aspects of neonatal breathing patterns are correlated with heart rate variability. Three spectral regions of heart rate variability could be identified: a very low frequency region below 0.02 Hz; a low frequency region from 0.02-0.20 Hz; and a high frequency region above 0.20 Hz. The dominant heart rate variability activity in these neonates was seen in the very low and low frequency regions, with little activity in the high frequency regions. In contrast to older infants and adults, respiration and heart rate variability were not strongly related through a high frequency region respiratory sinus arrhythmia but rather through a breath amplitude sinus arrhythmia which occurs in the low frequency region of the spectrum. The prominent very low frequency activity and the low frequency activity ascribed to breath amplitude modulation may result from autonomic nervous system mediation of chemoregulation.

Arrhythmias, Cardiac↗
PubMed1985

Platelet-monoamine oxidase activity in Reye's syndrome.

Platelet and liver monoamine oxidase (MAO) activity (mean +/- SD) was evaluated in patients with liver-biopsy-proven Reye's syndrome. MAO was measured by a radioenzymatic technique with [3H]tyramine as a substrate. A marked decrease in MAO activity [3.3 +/- 2.4 nmol of [3H]4-hydroxyphenylacetic acid formed X (mg protein)-1 X h-1] was observed in platelets on admission in all patients (n = 13) with Reye's syndrome when compared with hospitalized patients without liver disease (n = 8) [9.8 +/- 2.5 nmol of [3H]4-hydroxyphenylacetic acid formed X (mg protein)-1 X h-1] and with liver disease (n = 10) [9.1 +/- 2.0 nmol of [3H]4-hydroxyphenylacetic acid formed X (mg protein)-1 X h-1]. Following recovery from the disease, platelet MAO approached levels that were not significantly different from those of controls. Contrastingly, reduction of hepatic MAO in Reye's syndrome was similar to that seen in patients with liver disease of different etiologies. These studies suggest that reduced platelet MAO activity is a specific abnormality in Reye's syndrome, and it may be representative of generalized impairment of mitochondrial function in these patients. Furthermore, the pattern of liver and platelet MAO activity in Reye's syndrome may allow for the differentiation of this disease from other hepatopathologic conditions.

Adolescent↗
PubMed1984

Hypercatecholaminemia in Reye's syndrome.

To evaluate the role of catecholamines in Reye's syndrome, a specific and sensitive radioenzymatic assay was used to study plasma and CSF concentration of dopamine, norepinephrine, and epinephrine in 14 patients with liver-biopsy-proven Reye's syndrome. The results (median and range) revealed significant (P less than .04, P less than .0024, and P less than .030, respectively) elevation in plasma dopamine (131, 0 to 1,193 pg/mL), norepinephrine (1,455, 20 to 5,271 pg/mL), and epinephrine (345, 7.6 to 2,504 pg/mL) at the onset of the disease when compared with the level of these neurotransmitters in a group of hospitalized patients without hepatic disorders. There was a positive correlation between plasma catecholamines and stage of coma on admission (r = .54 to .86; P less than .001 to .024). Furthermore, the concentration of dopamine, norepinephrine, and epinephrine in the CSF increased significantly during the development of cerebral edema in all patients with Reye's syndrome as compared with concentrations in a control population. Hypercatecholaminemia may contribute to the encephalopathy of Reye's syndrome.

Adolescent↗
PubMed1983

Range-gated pulsed Doppler ultrasonographic evaluation of carotid arterial blood flow in small preterm infants with patent ductus arteriosus.

Range-gated pulsed Doppler (RGPD) ultrasonography was utilized to study the effect of a patent ductus arteriosus (PDA) on carotid arterial blood flow in small preterm infants. Carotid arterial flow velocity studies were performed on 23 preterm infants, sampling right and left carotid arteries. Studies on seven infants after PDA ligation and on seven who developed no evidence of PDA were used as controls. A strong relationship was demonstrated between diastolic reversal in the carotid arteries and PDA. The results of this study indicate that the RGPD flow velocity curve from the carotid artery is more sensitive than M-mode echocardiography or clinical examination in detecting PDA, and that PDA in small preterm infants is associated with a distinct abnormality in the carotid arterial flow pattern.

Blood Flow Velocity↗
PubMed1983

Abnormal regulation of pyridoxal 5'-phosphate in Reye's syndrome.

Seeking to determine the effect of liver disease associated with Reye's syndrome on the regulation of plasma pyridoxal 5'-phosphate, we measured this compound in plasma from 11 patients with biopsy-proven Reye's syndrome. Its concentrations in plasma are significantly higher [37.5 (SD 6.13) micrograms/L] at the onset of the disease than after treatment [8.50 (SD 2.9) micrograms/L] or in a group of hospitalized patients with no evidence of liver disease [8.4 (SD 1.5) micrograms/L]. The concentration of pyridoxal 5'-phosphate in plasma at the time the patients entered the hospital correlated significantly with their activities of serum alanine aminotransferase.

Adolescent↗
PubMed1983

Relationship between pressure passivity and subependymal/intraventricular hemorrhage as assessed by pulsed Doppler ultrasound.

A prospective study was undertaken using a range-gated, pulsed Doppler velocimeter to study flowpressure relationships in the anterior cerebral artery. Serial velocity and pressure studies were performed with each infant serving as his or her own control. The hypothesis tested was that ill preterm infants sustaining subependymal/intraventricular hemorrhage would have absent autoregulation. The hypothesis has been tested in 88 studies on 32 infants. Of 32 infants studied, 15 were judged to be pressure passive; nine of these children bled. The other 17 infants were not pressure passive; eight of these children bled (P greater than .05). From these studies, it may be concluded that the pressure passive state is not the final common link in the genesis of subependymal/intravertricular hemorrhage. Pulsed Doppler ultrasound may provide an extremely useful noninvasive technique for studying both the arterial and venous sides of the cerebral circulation.

Blood Flow Velocity↗