Evaluation of Vestibular Stimulation to Help Occasional Sleeplessness

Inclusion Criteria: * Males and females, ages 21- 50 attempts will be made to enroll equal distributions of males and females * Able and willing to provide written informed consent * Self reported habitual bedtime between 2100 and 0100 hours, which does not vary by more than 1 hour at least 5 nights per week * Self reported 7.5-9 hrs. habitual sleep time * Able to commit to 9 hrs of sleep opportunity throughout the study, but especially for the 3 nights prior to their PSG * Pass Berlin questionnaire, i.e. low likelihood of sleep disordered breathing * No history or evidence of RLS(restless leg syndrome) /PLMS (periodic limb movement syndrome) /Narcolepsy, no non-respiratory related sleep disorders. Exclusion Criteria: * Regular use of a pack or more per day of tobacco products * Typically consumes more than 2 (12 oz) caffeinated beverages per day * Self reported history of motion sickness * Participation in a study of investigational or marketed drugs or devices during the 30-day period prior to the start of the study or during the study * Clinically significant medical or psychiatric condition as determined by the investigator * Probable diagnosis of a current sleep disorder including but not limited to insomnia, sleep apnea, restless legs syndrome, or periodic limb movement disorder * History of current or recent (e.g. within past 5 years) alcohol, narcotic or any other drug abuse as defined by the Diagnostic and Statistical Manual of Mental Disorders of the American Psychiatric Association, 4th Edition (DSM-IV) * Currently works night shift or rotating shift * Travel or planned travel across more than 1 time zone within one week prior to randomization * Use of any medication that, in the opinion of the investigator, may alter sleep or wakefulness. (See Appendix E: Guideline For Medications Commonly Associated With Alterations Of Sleep / Wake Functioning). Subjects will undergo urine drug testing. * Consumption of more than 14 alcoholic drinks per week, or the recent consumption of more than 4 alcoholic drinks in one night. Subjects will be tested for alcohol, using a saliva test kit. * Pregnancy (will confirm absence of pregnancy with a urine or serum pregnancy test in women's of child bearing age). * Presence of a pacemaker * Presence of epilepsy or other uncontrolled medical conditions. * Prior participation in a VirtuSom protocol * History of vestibular disorders, (such as vertigo)