Melatonin for sleep EEG.

Melatonin 3 mg and secobarbital 100 mg assigned randomly were given to 40 psychiatric patients for sleep induction during EEG recording. Nine patients who did sleep naturally comprised a comparison group. EEGs were read blind; most were interpreted as mildly abnormal or within normal limits. No statistically significant differences between the three groups were observed in response to photic stimulation, hyperventilation or in frequency of paroxysmal variants. The electroencephalographer was able to identify the melatonin patients significantly more accurately than those who received secobarbital on the basis of lack of EEG manifestations of fast frequencies typical of barbiturate effects. Self-assessments of drowsiness, anxiety and performance on a perceptual-motor task were similar in the melatonin and secobarbital patients. However, the secobarbital group showed more impairment on a locomotion test than those who received melatonin or slept spontaneously. The results suggest that melatonin is a plausible alternative for EEG sleep sedation, especially for ambulatory patients.

Sleep induction for EEG revisited: technical note.

Forty-two patients each were randomly assigned in equal numbers to receive either zolpidem or secobarbital for sleep EEG recording. Three groups were compared; zolpidem, secobarbital and a control group of patients who drowsed spontaneously. All patients were evaluated before and immediately after the EEG and several hours later with measures of anxiety, perceptual-motor performance, locomotion, and subjective judgments of sleepiness. EEG response to standard activation procedures, signs of drowsiness and sleep and overall diagnoses were compared among the three groups. No differences emerged in demographic measures, psychiatric diagnoses, current drug treatment and experience with hypnotics. There were no statistically significant differences among the three groups or between the patients receiving the hypnotics on the anxiety performance and locomotion measures or degree of alertness. As a result of the experimental design, the unmedicated control patients showed EEG signs of drowsiness and sleep significantly sooner than patients receiving hypnotics. They also showed more slow or paroxysmal activity in response to hyperventilation, which may have been due to their greater effort. These results led us to retain secobarbital as the hypnotic for EEG sleep, mainly for economic reasons.

Deep advective transport of lithogenic particles in panama basin.

Sediment traps were deployed at several depths between 660 and 3800 meters in the Panama Basin. The flux of lithogenic particles increased with increasing depth. This increase was due primarily to particles of beidellite (a smectite clay), which was identical to the clay occurring in bottom sediment on the continental slope to the west of the sediment trap mooring. The beidellite vertical flux at the Panama Basin station increased when an easterly current prevailed and decreased when the current reversed, indicating that a major portion of smectite was transported horizontally at mid-water depth to the mooring site from the nearby continental slope.