SummaryExcessive daytime sleepiness is a complaint characterizing many disorders of the wakefulnesssleep cycle. This paper addresses the complaint of sleepiness objectively by an attempt to differentiate a group of control subjects from a group of patients with unambiguous narcolepsy. Fourteen control and 27 narcoleptic subjects were evaluated by one of three protocols involving nocturnal recordings, detailed interviews, and 5 or more 20-min opportunities to sleep offered at 2-h intervals beginning at 10.00 o'clock, ±30 min. Each 20-min opportunity to sleep was given to subjects lying in a darkened quiet room and asked to try to fall asleep. Polysomnographic variables were monitored and sleep was scored in 30-sec epochs by standard criteria. The interval from the start of each test to the first epoch of NREM (including stage 1 sleep) or REM sleep was called sleep latency. In two of the protocols, the subjects were awakened immediately after sleep onset. In the third protocol, the subjects were awakened after 10 min of sleep. Narcoleptics consistently fell asleep much more readily than did control subjects. We conclude that the Multiple Sleep Latency test, in addition to providing opportunities to clinically document sleep onset REM sleep periods, can demonstrate pathological sleepiness. Based on these data, we suggest that an average sleep latency less than 5 min be set as the minimum cutoff point for pathological sleepiness.Excessive daytime sleepiness (EDS) is a complaint characterizing many disorders of the wakefulness-sleep cycle (Guilleminault and Dement 1977). Despite the potential dangers to life and property of EDS, complaints are frequently unevaluated by physicians because there are few objective tools available to confirm pathological sleepiness.Traditional approaches to the study of sleepiness have included performance tests such as those developed to evaluate the consequences of sleep deprivation and various work-rest schedules (e.g., Wilkinson el al. 1968), and pupillography (Yoss et al. 1969). These approaches rely on a statistical relationship between an operational definition of sleep deprivation or a subjective measurement of sleepiness on the one hand and a behavioral or psychophysiological parameter on the other hand.More recently, Carskadon and Dement (1977) suggested that sleep latency (defined as the time between the point when an individual tries to sleep and the point when electroencephalographic patterns of sleep first develop) measured repeatedly in controlled nap situations might prove a useful tool in evaluating pathological sleepiness.Such a multiple nap procedure offers several advantages over performance testing, subjective tests, and pupillography. First, the concept of sleep latency as a measure of sleepiness has face validity, since presumably one who is sleepy will fall asleep more quickly than one who is not sleepy. Second, the use of sleep latency as a measurement of sleepiness is less subject to the confounding influences of muscle fatigue, motivation and practice than are...

Five patients with nocturnal myoclonus (periodic leg movements during sleep), mean age 59.6 years, were monitored polygraphically for fifteen successive nights. Using a double-blind drug study design with placebo at baseline, we investigated the effect of baclofen on these patients. All patients had the repetitive sleep-related abnormal movements during both the baseline nights and those on which baclofen had been administered. The number of movements varied during the four baseline nights, but the movements induced sleep fragmentation, i.e., very short electroencephalographic changes. Baclofen increased the number of movements but decreased their amplitude during non-rapid eye movement (REM) sleep and shortened the interval between movements. Its effect on sleep was dose related: as dosages increased, delta sleep progressively increased and REM sleep decreased. Sleep fragmentation resulting from muscle twitches decreased, as indicated by the diminution in alpha electroencephalographic arousals and K complexes. Baclofen dosages of 20 mg and 40 mg were the most efficacious.

Six young adult patients with grade I myotonic dystrophy and a complaint of daytime somnolence underwent 36-hour polygraphic monitoring, dynamometric and electromyographic studies before and under baclofen (60 mg/daily). Patients with the most severe daytime sleepiness had pathologic Sleep Apnea Indexes. After 6 weeks' ingestion of baclofen, no subjective or objective effect on patient symptomatology was found.

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