Sam Messin

Wrist actigraphic measures of sleep and rhythms.

With a piezo-electric activity transducer, wrist activity recordings were made simultaneously with EEG, EOG and EMG recordings. Wrist activity alone was used to estimate Total Sleep Time and blind independent scoring of sleep and wakefulness by EEG-EOG-EMG was done. Correlations between the two methods were termined for minutes of Sleep (r = 0.98), Total Sleep Period (r = 0.95) and minutes of Wake Time Within Sleep (r = 0.85). Continuous wrist activity recordings may thus provide inexpensive but very accurate estimates of Sleep Time.

Natural light exposure of young adults

Bright light has a role in natural coordination of mammalian circadian and seasonal rhythms. In humans, the light intensity must probably exceed 2000 lux to be optimal. Natural light exposures of 10 healthy adults were measured over a 24-hour period, using forehead illumination transducers connected to a portable computer. The subjects varied markedly in duration and timing of exposures to light greater than 2000 lux. On average, the subjects experienced bright light for only 90 minutes per day, less than the 3-8 hours of bright light necessary to maximally synchronize human circadian rhythms. These results suggest that natural and artificial light exposure for many Americans may be suboptimal for circadian and seasonal synchronization.

The Application and Utilization of an Ambulatory Recording System for the Screening of Sleep Disorders

ABSTRACT.It has become apparent in the last few years that many sleep complaints expressed by patients may involve cessation of breathing during sleep (apnea) or severe leg jerks (periodic movements in sleep-PMS), causing brief arousals throughout the night. The most commonly used practice for screening of these two disorders has been an all-night laboratory polysomnogram, which records sleep/wake, respiration, and leg movements. This technique involves, for the patient, a high cost, restriction of movement, and an unfamiliar and sometimes frightening setting. During the last few years our laboratory has used a portable ambulatory recording method to screen for sleep apnea and PMS, establishing a reliable and comfortable screening procedure in the patients own home. The overall cost of an initial screening is thus reduced, as is the time spent by the technician who, in the laboratory, would monitor the patient all night. This method allows more patients to be screened by one technician and allows easy ap...

An implantable eye movement transducer

Abstract A small implantable piezo-ceramic transducer provides a sensitive eye movement detector which is insensitive to EEG artifact.