Erwin Cw

Subjective hypnotic efficacy of trazodone and zolpidem in DSMIII–R primary insomnia

Trazodone is an antidepressant which is used at low doses as a hypnotic. The hypnotic efficacy of trazodone in non‐depressed insomniacs is unknown, especially in comparison to hypnotic medications such as zolpidem. Following a placebo screening week, DSM‐IIIR defined primary insomniacs were randomized into a parallel‐group, double‐blind, 14‐day comparison of trazodone 50 mg, zolpidem 10 mg and placebo. Patients completed daily morning questionnaires and weekly office visits. Self‐reported sleep latencies were compared by the Cox proportional hazards regression technique; self‐reported sleep duration by ANOVA. During treatment Week 1, both drugs produced significantly shorter self‐reported sleep latencies and longer self‐reported sleep durations than placebo. Self‐reported sleep latency was significantly shorter with zolpidem than with trazodone. During Week 2, only the zolpidem group maintained a significantly shorter sleep latency than the placebo group, and self‐reported sleep duration did not vary significantly among groups. The incidence of adverse events was low in all groups. Both trazodone and zolpidem improved self‐reported sleep latency and duration of non‐depressed, primary insomniacs; zolpidem was somewhat more efficacious at the doses studied.

Intraoperative brainstem auditory evoked potentials Significant decrease in postoperative morbidity

Evoked potentials are commonly used for intraoperative monitoring of neural tissue under surgical threat despite the lack of unequivocal evidence demonstrating its effectiveness in preventing neural injury. This study retrospectively compares the auditory morbidity of posterior fossa microvascular decompressive surgery before and after the introduction of intraoperative brainstem auditory evoked potentials (BAEPs). All patients underwent a similar operative procedure performed by a single surgeon. The two groups were comparable with regards to age, sex, and indications for surgery. In the nonmonitored group, auditory morbidity had not declined with increasing experience of the surgeon. Ten of 152 patients (6.6%) suffered a profound hearing loss in the nonmonitored group. In the monitored group, none of 70 patients suffered a profound hearing loss. We attribute this significant decline (p = 0.02) in morbidity to the introduction of intraoperative BAEPs. We believe this to be the first demonstration of a significant decrease in operative morbidity directly associated with the use of intraoperative evoked potential monitoring.

Efficacy and Tolerability of 14-Day Administration of Zaleplon 5mg and 10mg for the Treatment of Primary Insomnia

AbstractObjective: The efficacy and tolerability of zaleplon 5mg and 10mg, a selective benzodiazepine subtype A receptor agonist, was evaluated during 14-day administration in a double-blind, placebo-controlled design, with triazolam included as an active comparator. Patients and Methods: Polysomnographic data, subjective reports, performance measures, and clinical assessments were made for 132 primary insomniacs, aged 18 to 60 years, during three baseline, 14 drug, and two discontinuation nights. Results: Polysomnographic data indicated that both doses of zaleplon shortened latency to persistent sleep relative to placebo, during early drug administration. By the end of the administration period the difference was no longer statistically significant, principally due to improvement in the placebo group. No effect on total sleep time or measures of awakenings was seen with either zaleplon dose. Triazolam increased total sleep time and reduced latency to persistent sleep compared with placebo on early drug nights, but not at the end of the 2-week administration. In general, subjective data were consistent with polysomnography findings. Clinical evaluations indicated that zaleplon was well tolerated and without residual effects or discontinuation effects. Adverse effects were infrequent, mild and no more common with zaleplon than with placebo. Conclusion: At the doses evaluated, zaleplon appeared to have hypnotic properties consistent with its pharmacokinetic profile, and a low likelihood of undesired effects.

Abnormal sensory evoked potentials in amyotrophic lateral sclerosis

We have reviewed sensory evoked potential (EP) findings in 17 patients with amyotrophic lateral sclerosis (ALS). Somatosensory EPs were abnormal in 7 of 16 patients after lower-extremity stimulation and in 2 of 16 patients after upper-extremity stimulation. Brainstem auditory EP abnormalities were found in 2 of 12 patients. No abnormalities were noted on pattern reversal visual EPs in 12 patients. Overall, 47% of all ALS patients studied had at least one EP abnormality. EP evidence of CNS sensory dysfunction in ALS is more frequent than that noted clinically or pathologically and offers further support to previous observations of sensory system involvement in ALS.

Effects of buspirone and diazepam, alone and in combination with alcohol, on skilled performance and evoked potentials

Effects of buspirone, 10 and 20 mg, and diazepam, 10 mg, on skilled performance and evoked responses, as well as their interactions with 0.8 g/kg of alcohol were investigated in 24 healthy men. Alcohol, 0.8 g/kg, caused the greatest performance impairment, followed closely by diazepam. Both doses of buspirone had lesser effects. Buspirone had primarily sedative effects which were short lasting, whereas diazepam impaired tracking and body balance in addition to being sedative. Both anxiolytics showed only slight additive interactions with the present dose of alcohol. A strong drug effect and a lesser but significant alcohol and a drug/alcohol interaction effect were seen on evoked potentials. Diazepam effects on evoked potentials were similar to alcohol, whereas buspirone in some instances appeared to reverse the alcohol effect. Pharmacokinetics of buspirone and diazepam were not significantly affected by concomitant administration of alcohol. The psychomotor side effect profile of a single anxiolytic dose of buspirone is preferable to a single 10-mg dose of diazepam.

Acute effects of electroconvulsive therapy on brain stem auditory-evoked potentials

The acute effects of electroconvulsive therapy on brain stem auditory evoked potentials were investigated in 6 psychiatric inpatients. Even during the induced seizure, no significant effects were noted, a finding consistent with the stability of these far-field potentials.

Evoked potential analysis: On-line signal optimization using a mini-computer☆

An automated computer-based system is described for the analysis of evoked potentials. All procedures are carried out in real-time A small computer performs the following functions; timing of random stimulus presentation, rejection of artifact contaminated responses, collection of digital data, computation of averaged evoked responses, computation of the Wiener filter, storage of the filtered and unfiltered averages and display of the resultant averages. The Wiener filter as described by Walter (1969) and Doyle (1975) is used to improve the estimate of the evoked potential by discriminating against frequencies likely to be contaminated with noise. The defining equation for the Wiener filter states that information at any frequency is to be weighted by the ratio of the power known to be in the signal (response) at that frequency over the corresponding power known to be in both the signal (response) and the noise (background EEG) at the same frequency. The technique requires the computation of the Fourier transform for each response in order to produce the power spectra necessary for the Wiener filter. Earlier reports dealing with this technique have usee large computers to analyze the evoked potential data off-line. The system described here allows for greater routine utilization of this powerful technique and the concomitant automated rejection of artifact contaminated responses. Highly improved estimates of the evoked potential are resultant using a minimal number of stimuli.

A review of electroencephalographic features of normal sleep.

Summary: The electrographic features of sleep have been studied intensively using both routine electroencephalography and polysomnography. The two sections of this paper describe and illustrate the major characteristics of sleep physiology and associated clinical electroencephalography. In the first section, criteria for definition of sleep stages are presented and correlated with the phasic and tonic physiological events noted to occur as a function of sleep stage. The phytogeny and ontogeny of sleep are discussed as well as the neurophysiological mechanisms that may underlie sleep control. The second section presents a clinically oriented description of the patterns and events of the sleep electroencephalogram as seen in a normal adult and pediatric population.

Delayed Development of Sensorineural Hearing Loss After Neonatal Hyperbilirubinemia: A Case Report with Brain Magnetic Resonance Imaging

Sensorineural hearing loss has long been known to be a clinical consequence of kernicterus. Brainstem auditory evoked potentials (BAEPs) that occur in hyperbilirubinemic infants, can be reversed in the neonatal priod by exchange transfusion. The case was reported in an infant with neonatal hyperbilirubinemia from hemolysis due to glucose‐6‐phosphate dehydrogenase (G6PD) deficiency and napthalene exposure. BAEPs showed that the baby had normal hearing at 30 decibels at 13 days of age. after exchange transfusions, but had developed profound bilateral sensorineural hearing loss by 7 months of age. The brain magnetic resonance imaging (MRI) findings at 7 months are also presented.

BAEPs IN INFANTS WITH MYELOMENINGOCELE AND LATER DEVELOPMENT OF CHIARI II MALFORMATION‐RELATED BRAINSTEM DYSFUNCTION

Thirty‐seven infants with myelomeningocele received brainstem auditory evoked potentials (BAEPs) at a median age of eight days. No infant had brainstem dysfunction at the time of testing. Median follow‐up was at 30 months. Of 12 infants who subsequently developed brainstem dysfunction at a median age of three months, 11 had had abnormal neonatal BAEPs. In contrast, only 10 of 25 infants who did not develop brainstem dysfunction had abnormal BAEPs. The mean average I‐V interpeak latencies was greater among those who developed symptoms than among those who did not. Neonatal BAEPs can identify a group of asymptomatic infants with myelomeningocele who need close follow‐up for the subsequent development of brainstem dysfunction.