A 2015 systematic review of 15,521 men found "no indications of differences in racial variability", and stated that it was not possible to draw any conclusions about size and race from the available literature and that further research needed to be conducted.According to Aaron Spitz, a urologist, many websites and studies promoting variation of penis size between races use unscientific methods of collecting information and often ignore contradictory evidence. He concludes that "when you really take a good look at the naked data, there’s not a whole lot there [showing racial variation in penis size]." Size preferences among sexual partners
In a 1994 cover story by Psychology Today, 1,500 readers (about two-thirds women) were surveyed about male body image. Many of the women were not particularly concerned with penis size, and over 71% thought men overemphasized the importance of penis size and shape. Generally, the women polled cared more about width than men thought, and less about length than men thought, although the strength of caring for either among women showed a similar pattern. In a small study conducted by University of Texas–Pan American and published in 2001 in BMC Womens Health, 50 undergraduate women were surveyed by two popular male athletes on campus about their perceptions of sexual satisfaction and it was concluded that the width of a penis feels better than the length of a penis, when subjects are asked to choose between the two (size was left unspecified).
It comprises a lot of electrodes which measure physiological variables related to sleep. Polysomnography often includes electroencephalography, electromyography, electrocardiography, muscle activity and respiratory function.Polysomnography is helpful to identify the very short sleep onset latency period, the very efficient sleep (more than 90%), the increased slow wave sleep, and sometimes an elevated amount of sleep spindles in idiopathic hypersomnia patients. Multiple sleep latency test (MSLT)
The multiple sleep latency test (MSLT) is an objective tool which indicates the degree of sleepiness by measuring the sleep latency (i.e. the speed of falling asleep). It also gives information regarding the presence of abnormal REM sleep onset episodes. During that test, patients have a series of opportunities to sleep at 2-h intervals across the day in a darkened room and with no external alerting influences.The MSLT is often administered the day after recording the polysomnography, and the mean sleep latency score is often found to be around (or less than) 8 minutes in idiopathic hypersomnia patients. Some patients might even have a sleep onset latency of 5 minutes or less. These patients are often even more aware of sleeping during naps than narcolepsy patients. Actigraphy
Actigraphy, which operates by analyzing the patients limb movements, is used to record the sleep and wake cycles. In order to report them, the patient has to wear continuously a device on his or her wrist, which looks like a watch and does not contain any electrodes. The advantage actigraphy shows over polysomnography is that it is possible to record for 24-hours a day for weeks.