Nocturnal myoclonus: treatment efficacy of clonazepam and temazepam.

Clonazepam (1 mg h.s.) and temazepam (30 mg h.s.) were studied in 10 patients diagnosed as having insomnia with nocturnal myoclonus. Each subject underwent two nocturnal polysomnographic recordings while drug-free, two during treatment with clonazepam, and two during treatment with temazepam. Treatment sessions were 7 days long, and recordings were done on nights 6 and 7 of the treatment sessions. A 14-day washout period separated the treatment sessions. The order of drugs used in the first and second treatment sessions was randomized. Objective and subjective sleep laboratory data showed that both drugs improved the sleep of patients with insomnia in association with nocturnal myoclonus. Neither drug significantly reduced the number of nocturnal myoclonic events. Sleep changes were consistent with those produced by sedative benzodiazepines in general. Thus, the data support clinical reports that clonazepam, a benzodiazepine marketed for the indication of seizure, is useful in improving sleep disturbances associated with nocturnal myoclonus. Temazepam, a benzodiazepine marketed for the indication of insomnia, was found to be a suitable alternative to clonazepam in the treatment of insomnia associated with nocturnal myoclonus. The present data and other studies suggest the need for a model that explains why leg movements and sleep disturbances may wax and wane independently.

REM sleep episodes during the maintenance of wakefulness test in patients with sleep apnea syndrome and patients with narcolepsy.

Twelve patients with sleep apnea, 12 narcoleptic patients, and 10 controls were given 20-min opportunities to remain awake while sitting comfortably. Test sessions were administered at 10:00, 12:00, 14:00, 16:00, and 18:00. Apneic and narcoleptic subjects were less capable of maintaining wakefulness than controls. Patients with sleep apnea had an average of 1.4 daytime rapid eye movement (REM) episodes with the peak incidence at 14:00. Narcoleptics also had sleep onset REM periods (mean of 2.7), whereas none of the controls had REM episodes during the daytime testing. Narcoleptic and control groups differed in the probability of REM occurring at each session. There were time-of-day differences in the probability of REM occurring between patient groups. The amount of stage REM the night preceding testing was unrelated to the occurrence of REM episodes during the day in either patient group. In addition, there were notable differences in the frequency of sleep onset REM periods when patients were sitting as opposed to being supine during nap studies. Sleep latency and frequency of REM episodes on the maintenance of wakefulness test were independent of the subject's age. The maintenance of wakefulness test proved unsatisfactory as a diagnostic procedure, but appeared useful as an adjunct procedure in the evaluation of treatment efficacy of hypersomnia.

Forty-eight-hour polysomnographic evaluation of narcolepsy.

Eleven narcoleptic and 11 control subjects completed five multiple sleep latency test (MSLT) procedures with instructions to "fall asleep" while supine and five maintenance of wakefulness test (MWT) procedures with instructions to "remain awake" while comfortably sitting. Narcoleptic subjects had a shorter sleep latency and a higher frequency of sleep onset REM periods (SOREMPs) on both daytime tests than controls. Each group had a longer sleep latency on the MWT than MSLT. For patients with narcolepsy, the differences between the two daytime procedures suggest the tests measure distinct aspects of sleep-wake tendency. Sleep latency on the MSLT did not correlate with sleep latency on the MWT for narcoleptic subjects. Furthermore, the number of SOREMPs during the MSLT for narcoleptic subjects did not correlate with the number of SOREMP during the MWT. Measures of nocturnal REM sleep for narcoleptic subjects correlated with sleep latency on the MSLT. In particular, REM latency at night was highly predictive of the magnitude of hypersomnia for patients with narcolepsy. Sleep latency at night tended to relate to sleep latency on the daytime tests for controls. Patients with narcolepsy had a shorter sleep latency, more frequent arousals, and a shorter REM latency than control subjects across the 2 nights of study.

Treatment of narcolepsy: objective studies on methylphenidate, pemoline, and protriptyline.

Methylphenidate, pemoline, and protriptyline were studied for their treatment efficacy in narcolepsy. A low, intermediate, and high dose level of each drug was studied for 1 week. For methylphenidate the doses were 10, 30, or 60 mg/day; for pemoline, 18.75, 56.25, or 112.5 mg/day; and for protriptyline 10, 30, or 60 mg/day. The order of dose levels was random from subject to subject and the daily dose was divided into thirds and taken in identically appearing capsules morning, noon, and afternoon. Subjects were 6 narcoleptic patients studied on methylphenidate (5 women and 1 man; mean age 54.5 + 11.7 years), 7 narcoleptic patients studied on pemoline (5 women and 2 men; mean age 43.0 + 7.1 years), and 4 narcoleptic patients studied on protriptyline (2 women and 2 men; mean age 42.5 + 16.9 years). Testing consisted of day-long sessions occurring at the end of each dose level and involving a clinical status questionnaire as well as maintenance of wakefulness, Wilkinson addition, and Digit-Symbol Substitution tests. Results were compared with 9 control subjects with no sleep disorder (5 women and 4 men; mean age 39.2 + 8.4 years) who were given placebo that was purported to be a "stimulant drug" and tested in a similar manner. Results demonstrated profound differences in ability to stay awake and perform between narcoleptic patients and controls. Data also suggested that methylphenidate significantly improves ability to stay awake. Pemoline seems to improve ability to perform. Protriptyline does not significantly alter ability to stay awake or to perform.

Obstructive sleep apnea and body weight.

A patient with obstructive sleep apnea was monitored five times during three years while his weight fluctuated within a range of 26 kg. The number of apneas per hour of sleep varied from 59.6 at 111 kg of weight to 3.1 at 85 kg. The relation between apneas per hour of sleep and body weight was a logarithmic function. A modest decrease in weight was thus associated with a disproportionally larger decrease in the rate of apneas. Typical SaO2 levels during the apneic episodes also had a logarithmic relation with body weight. Apnea-related sinus bradycardia and sinus tachycardia were only present at the highest weight. The results suggested that dieting and weight loss lead to an improvement in sleep apnea and related sequelae.

Tobacco use by narcoleptics and daytime sleep tendency.

The nocturnal sleep and daytime sleep tendency were assessed in 10 narcoleptics who regularly smoked cigarettes and 10 narcoleptics who did not use tobacco. Standard sleep-wake polygraphic measures were recorded during the 24-h study. There were no statistical differences between groups in terms of nighttime sleep structure, although tobacco use resulted in a decreased sleep duration. Smokers tended to fall asleep more rapidly than non-smokers throughout daytime multiple sleep latency testing. The data failed to demonstrate a daytime arousal effect of tobacco for patients with narcolepsy.

Human auditory evoked potentials: reliability of intensity functions.

This investigation assessed the relative reliability of the human auditory evoked potential (AEP) amplitude-intensity and latency-intensity functions. Averaged AEP waveforms to 10 levels of stimulus magnitude were obtained from bipolar recordings. Variability and slope of group functions were constant, as indicated by nonsignificant differences in day-to-day residual variances and intersession regression coefficients. Periodic change in amplitude or latency thus indicated a shift of the entire function. Individual N1--P2 amplitude-intensity functions were similarly reliable, while individual P2--N2 amplitude and latency measures tended to be more variable. No significant differences were obtained across sessions for regression coefficients based on either group or individual data. Intersession AEP amplitude and latency apparently varied systematically with stimulus intensity.

Determination of sleep latency in polysomnographic evaluations of daytime somnolence in patients with sleep apnea and patients with narcolepsy.

Sleep onset during the multiple sleep latency test was scored by three criteria for 21 patients with narcolepsy and 21 patients with obstructive sleep apnea: a single epoch of stage 1, three consecutive epochs of stage 1, and a single epoch of stage 2 or REM. Mean sleep latency for both groups was predictably shortest using a single epoch of stage 1 and longest using a single epoch of stage 2 or REM. All estimates of sleep latency were highly correlated. It was concluded that a single epoch of any stage of sleep is an appropriate measure of sleep latency for patients with narcolepsy, although a modified scoring system should be developed for patients with sleep apnea. The obstructive apneic episodes prevented or delayed sleep onset on 4.8% to 33.3% of trials depending on the specific criteria used to determine sleep latency. Such apnea-related interruptions to sleep should be taken into account when assessing daytime somnolence in patients with sleep apnea.

Hypersomnia and the perception of sleep-wake states: some preliminary findings.

35 hypersomniacs (20 with obstructive sleep apnea and 15 with narcolepsy) and 15 controls estimated sleep latency during systematic trials of attempting to remain awake during the day. The error in subjective assessment of sleep latency was more variable for both patient groups than for controls. In addition, narcoleptics could not provide a determination of sleep latency or differentiate sleep-wake states on nearly 23% of all trials. Ratings on a subjective sleepiness scale did not covary with objective sleep latency for any hypersomniac. The findings suggested that patients with either sleep apnea or narcolepsy had difficulty differentiating sleep and quiet wakefulness during the day.

Diurnal periodicity of the human vertex potential.

Averaged auditory evoked potential waveforms were recorded from the vertex of human subjects 3, 9, and 15 hr. after awakening. Responses to pure tones of 60 and 80 dB SL were obtained at each session. Amplitude measures of N1-P2 and P2-N2 components were largest in the morning followed by a gradual attenuation across sessions. Waveforms amplitude during the late evening ranged from 85% to 91% of the morning amplitude.

Articulatory phonology: an overview.

An overview of the basic ideas of articulatory phonology is presented, along with selected examples of phonological patterning for which the approach seems to provide a particularly insightful account. In articulatory phonology, the basic units of phonological contrast are gestures, which are also abstract characterizations of articulatory events, each with an intrinsic time or duration. Utterances are modeled as organized patterns (constellations) of gestures, in which gestural units may overlap in time. The phonological structures defined in this way provide a set of articulatorily based natural classes. Moreover, the patterns of overlapping organization can be used to specify important aspects of the phonological structure of particular languages, and to account, in a coherent and general way, for a variety of different types of phonological variation. Such variation includes allophonic variation and fluent speech alternations, as well as 'coarticulation' and speech errors. Finally, it is suggested that the gestural approach clarifies our understanding of phonological development, by positing that prelinguistic units of action are harnessed into (gestural) phonological structures through differentiation and coordination.

Some notes on syllable structure in articulatory phonology.

Two approaches to seeking stable patterns in the gestural organization of speech are examined: local organization (individual gestures coordinated with other individual gestures) and global organization (gestures forming larger conglomerates). Articulatory evidence from American English words with a variety of initial consonants and clusters shows that syllable-initial consonants form a global organization (indexed by a metric we term the C-center) that is coordinated with the syllable's vowel gesture. For syllable-final consonants, however, the evidence suggests that a local organization is employed: The first postvocalic consonant gesture is coordinated with the vowel gesture. Implications of these different styles of organization for the perceptual and phonological structure of speech are discussed.

Maintenance of wakefulness test: a polysomnographic technique for evaluation treatment efficacy in patients with excessive somnolence.

Ten patients with narcolepsy were given five 20 min opportunities to remain awake throughout the day. Trials were offered at 2 h intervals beginning at 10:00. Polysomnographic variables were monitored during each trial. Sleep latency increased when patients were instructed to maintain wakefulness compared to when instructed to sleep; however, sleep latencies were still lower for narcoleptics than for control subjects. Unexpectedly, we were not always able to document patients' reports of increased ability to stay awake. The findings suggested that clinical data on symptom control in narcolepsy do not predict ability to stay awake. Objective measures of the ability are potentially more useful in evaluating treatment.

Triazolam diminishes daytime sleepiness and sleep fragmentation in patients with periodic leg movements in sleep.

Fifteen subjects (9 men and 6 women) exhibiting objective evidence of excessive daytime somnolence and periodic leg movements in sleep underwent 4-7 days of treatment with triazolam (0.25 or 0.50 mg) and placebo in a double-blind crossover design. One night of polysomnography followed by daytime multiple sleep latency testing were conducted on the first and last days of each treatment block. By the last day of treatment, the mean multiple sleep latency test score after triazolam (9.0 minutes) was significantly greater than that after placebo (5.7 minutes). Thus, triazolam treatment led to a decrease in daytime somnolence. Triazolam also improved sleep architecture and continuity; it increased total sleep time, decreased the number of awakenings and arousals, and decreased stage 1 and increased stage 2 percentages. Although the frequency of periodic electromyographic bursts remained unchanged, the frequency of associated arousals decreased after treatment. Short-term treatment with triazolam is thus effective in diminishing daytime sleepiness and in improving sleep architecture, continuity and duration in patients with periodic leg movements in sleep. These effects do not seem to be mediated through a decrease in periodic leg movement activity.

Extracting dynamic parameters from speech movement data.

A quantitative characterization of articulatory movements, using the parameter values of a linear second-order dynamical system, was developed in order to compare classes of movements, in particular, classes defined by linguistic factors such as syllable position, stress, and vowel quality. Movements of the lower lip in utterances such as ['bibebib] and [babe'bab] were partitioned into sections ("windows") in two ways: at successive displacement peaks and valleys, and at the right edge of plateau regions around such extreme values. The linguistic factors affected natural frequency in similar ways regardless of whether damping ratio was permitted to vary or held fixed at one of several different values. Damping ratio was generally unaffected by the linguistic factors. For the most part, the type of partition or window did not affect the patterns of the results, with the exception of the closing gesture out of the reduced syllable.