The specific objectives of this experiment were:
Crewmembers that experience SMS were treated with PMZ. This delineated participants as test subjects versus control subjects. Before the first PMZ dose, participants collected a saliva sample; thereafter, saliva samples were collected at 1, 2, 4, 8, 24, 36, and 48 hours post-PMZ consumption. During the same time, participants ranked themselves using the Stanford Sleepiness Score (SSS), a standardized sleepiness index. The SSS consists of seven numbered statements describing subjective levels of sleepiness/alertness with 1 equal to wide awake and 7 equal to no longer fighting sleep/sleep onset soon. This entire protocol was repeated each time PMZ was taken. If a crewmember elected to take PMZ before sleep, saliva samples were collected pre-dose, just before sleep, immediately upon wake-up, one hour after wake-up, and at 24, 36, and 48 hours post-dose.
Both test subjects and/or control subjects wore a small light-weight activity and light recording device (Actiwatch). As soon as possible upon entry into orbit on flight day 1 (FD1), the crewmember donned the watch and wore it continuously throughout the flight. In addition to wearing the watch, crewmembers also recorded sleep time in a short paper sleep log every morning within 15 minutes of awakening. On the last day of the mission, the crewmember doffed and stowed the Actiwatch.
Approximately 30 days after landing (R+30), crewmembers who took PMZ in flight also participated in one additional data collection session. During a 48-hour data collection period, participants wore the Actiwatch activity monitor, took the same dosage and form of PMZ that was used in flight, completed the SSS, collected eight saliva samples following the same schedule as in flight, and recorded sleep times once a day.
There were a number of parameters that could be analyzed to measure performance on the PILOT at specific times during the approach and landing. In addition, the system provided a composite score (the JNM score) at the end of each landing. The investigators found no significant effect of PMZ on the JNM composite score and no significant correlation between the JNM score and the Stanford Sleepiness Scale. However, there were a number of points during the approach and landing where pitch and roll errors were significantly larger following PMZ compared to Placebo-saline (at 2-4 after drug administration). Unfortunately, due to hardware problems, approximately 50% of the individual parameter data were lost and unavailable for repeated measures analyses. Nonetheless, despite the loss of a large portion of this data differences between PMZ and Placebo in X and Y runway position approached significance.
Overall, the data supported the conclusion that PMZ affects landing performance. Moreover, it is important to note that the participants were all highly skilled at approach and landing tasks and that the conditions were all nominal. Under these conditions, it was expected that much higher doses of medications or alcohol are required to significantly disrupt performance. This leads investigators to suggest that PMZ (50mg IM) would be expected to produce greater disruption of task performance if the individual is not over-trained in the task, or if task performance occurs under off-nominal conditions.
This experiment has concluded. Results will be available once the investigator publishes her findings.
|Mission||Launch/Start Date||Landing/End Date||Duration|
|Expedition 13||03/22/2006||09/24/2006||186 days|
|Expedition 15||04/07/2007||10/21/2007||197 days|
|Expedition 16||10/10/2007||04/19/2008||192 days|