Simulated Driving Study in Restless Legs Syndrome

Lane position variability (LPV) was defined as the standard deviation of lane position, and was measured from the center line of the 26 foot wide 2-lane paved road to the center of the vehicle. Change from baseline in overall LPV was calculated as the Day 16 mean LPV over the 1-hour drive minus the Baseline mean LPV over the 1-hour drive. The Day 16 measurement is at the time of maximum concentration (Tmax) for both GEn and DPH.

Lane position variability (LPV) was defined as the standard deviation of lane position, and was measured from the center line of the 26 foot wide 2-lane paved road to the center of the vehicle. Change from baseline in overall LPV was calculated as the Day 14 (in the evening) or Day 15 (in the morning after GEn dosed at 5 PM) mean LPV over the 1-hour drive minus the Baseline (Day -1 or Day 1) mean LPV over the 1-hour drive.

Lane position was measured from the center line of the 26 foot wide 2-lane paved road to the center of the vehicle. Change from baseline in overall average lane position was calculated as the Day 14 (in the evening), 15 (in the morning after GEn dosed at 5 PM), or 16 (assessment at Tmax of GEn and DPH) mean lane position over the 1-hour drive minus the Baseline (Days -1 and 1) mean lane position over the 1-hour drive.

Speed variability was defined as the standard deviation of the speed (measured in miles per hour). Participants were instructed to maintain a speed of 55 miles per hour during the test drive. Change from baseline in overall speed variability was calculated as the Day 14 (in the evening), 15 (in the morning), or 16 (at Tmax of GEn and DPH) mean speed variability over the 1-hour drive minus the Baseline (Days -1 and 1) mean speed variability over the 1-hour drive.

Participants were instructed to maintain a speed of 55 miles per hour during the driving assessment. Change from baseline in overall average speed was calculated as the Day 14 (in the evening), 15 (in the morning), or 16 (at Tmax of GEn and DPH) mean speed over the 1-hour drive minus the Baseline (Days -1 and 1) mean speed over the 1-hour drive.

A simulated crash was defined as a collision with an oncoming car or obstacle (e.g., tree) or when the distance to the center line was greater than 18 feet on either side of the road.

Brake reaction time was assessed as the time it took for each participant to move their foot off the accelerator and onto the brake pedal after the appearance of a stop sign on the simulation screen. Change from baseline was calculated as the Day 14, 15, or 16 mean reaction time minus the Baseline (Days -1 and 1) mean reaction time.

Alertness VAS was completed immediately before and after each simulated driving assessment. Participants indicated their alertness by marking a vertical line on a horizontal scale anchored by responses "extremely sleepy" and "extremely alert." VAS score was determined by measuring the distance in millimeters (mm) from the left hand end of the line to the point the participant marked. Scores ranged from 0-100 mm, with higher scores indicating more alertness and lower scores indicating more sleepiness. Change score was calculated as the Day 14, 15, or 16 VAS score minus the Baseline VAS score.

The Epworth Sleepiness Scale (ESS) is a questionnaire designed to evaluate daytime sleepiness. Participants were asked to rate how likely they were to doze or fall asleep during 8 activities on a scale of 0 ("would never do") to 3 ("high chance of dozing"). The total score ranges from 0-24, with a score greater than 10 representing excessive daytime sleepiness (an increased chance of dozing). Change from baseline was calculated as the Day 14 total score minus the Baseline total score.

The BAC was designed as a comprehensive measure of cognitive function, including 6 individual tests: Verbal Memory Recall, Digit Sequencing, Token Motor Task, Verbal Fluency, Symbol Coding, and Tower of London. The composite/total BAC score is calculated by scoring each individual test, comparing each score to a healthy control sample (matched for sex and age category) to create z-scores, summing the z-scores, and rescaling the sum. The composite score range is -2127.8 to 1878.8, with higher scores indicating better cognition.

Participants were presented with 15 words and asked to recall as many as possible; the procedure was repeated 5 times. The total number of words recalled correctly across the 5 administrations of the list was the participant's Verbal Memory Recall score (range: 0-75). The scaled test score was calculated as ((BAC component raw test score - healthy control sample test mean)/healthy control sample test standard deviation); a healthy control sample was matched to the participant's sex and age category. The scaled test score range is -7.37 to 4.86; higher scaled scores indicate better cognition.

Participants (par.) were presented with sets of numbers of increasing length and asked to tell the experimenter the numbers in order from lowest to highest. The task has 7 levels; the first level had 2 digits in the set (e.g., 5, 2); the second level had 3 digits in the set, etc. The number of times the par. correctly arranged the numbers was recorded as the score for each level. The DSS is the sum of the 7 level scores (range: 0-28). The scaled test score was calculated as indicated for the Verbal Memory Test and ranges from -6.68 to 2.73; higher scaled scores indicate better cognition.

Participants were given 100 plastic tokens and asked to place them in a container, 2 at a time, as quickly as possible for 60 seconds. The number of tokens correctly placed in the container was the Token Motor Task score (range: 0-100). The BAC was conducted prior to each simulated driving test. The Token Motor Task scaled test score was calculated as indicated for the Verbal Memory Test. Change from baseline was calculated as the Day composite score minus the Baseline composite score. The scaled test score range is -6.95 to 3.35, with higher scaled scores indicating better cognition.

Verbal Fluency included one semantic fluency and two letter fluency tasks. Participants were given 60 seconds to name as many words as possible within a given semantic category (supermarket items), and in two separate trials, participants were given 60 seconds to generate as many words as possible that began with a given letter. The total number of words from all of the 3 trials was the Verbal Fluency score (range: 0-150). The scaled test score was calculated as indicated for the Verbal Memory Test. The scaled test score range is -5 to 10.83; higher scaled scores indicate better cognition.

Participants were given a list of numbers (numerals 1-9) that were each associated with a unique symbol. Participants decoded a list of 110 symbols as quickly as possible in 90 seconds. The total number of symbols correctly decoded was the Symbol Coding Score (range: 0-110). The Symbol Coding scaled test score was calculated as indicated for the Verbal Memory Test. Change from baseline was calculated as the Day composite score minus the Baseline composite score. The scaled test score range is -7 to 10.08, with higher scaled scores indicating better cognition.

Participants (par.) were asked to look at 2 pictures simultaneously; each picture showed 3 different colored balls arranged on 3 pegs. Par. were to estimate the number of times the balls in 1 picture would have to be moved to make the arrangement of balls identical to that of the second picture. Par. were allowed 20 seconds to respond to each pair of pictures. The number of correct items was the TOL Score (range: 0-22). The TOL scaled test score was calculated as indicated for the Verbal Memory Test. The scaled test score range is -7.53 to 2.76; higher scaled scores indicate better cognition.

The IRLS Rating scale is a measure of RLS disease severity and reflects the participant-reported assessment of primary sensory and motor features and associated sleep problems in RLS. Items are included that assess the impact of symptoms on participants' mood, daily life, and activities. The total score ranges from 0-40 points, with 40 being the most severe. The scale assesses symptoms over the week prior to measurement.

The CGI scale is a widely used tool designed to allow clinicians to rate the severity of illness and the change of the disease severity over time based on a seven-point rating scale, with a score of 1 being "very much improved" and a score of 7 being "very much worse" compared to baseline.

The investigator-rated CGI-I is a clinician-rated assessment designed to allow clinicians to rate the change of their participant's disease severity over time based on a seven-point scale, with a score of 1 being "very much improved," and a score of 7 being "very much worse" compared to baseline. For this endpoint, "response" was defined as a rating of "very much improved" or "much improved" (score of 1 or 2 on the scale) compared to baseline.

The participant-rated CGI-I scale is a self-rated assessment designed to allow participants to rate the change of their disease severity over time based on a seven-point scale, with a score of 1 being "very much improved" and a score of 7 being "very much worse".

The participant-rated CGI-I is a self-rated assessment designed to allow participants to rate the change of their disease severity over time based on a seven-point scale, with a score of 1 being "very much improved," and a score of 7 being "very much worse." "Response" was defined as a rating of "very much improved" or "much improved" (score of 1 or 2 on the scale).

The 24-Hour RLS Record is a diary in which participants report the presence and severity of RLS symptoms (none, mild, moderate, or severe) for a 24-hour period, in 30-min increments beginning at 8AM on the day prior to the visit. For Arms 2 and 3, upper limits of the confidence intervals are not available, as they are beyond the 24-hour time frame.

The 24-Hour RLS Record is a diary in which participants report the presence and severity of RLS symptoms (none, mild, moderate, or severe) for a 24-hour period, in 30-min increments beginning at 8AM on the day prior to the visit.

The 24-Hour RLS Record is a diary in which participants report the presence and severity of RLS symptoms (none, mild, moderate, or severe) for a 24-hour period, in 30-minute increments. The period was divided into 7 four-hour intervals (8 AM to 12 PM, 12 PM to 4 PM, 4 PM to 8 PM, 6 PM to 10 PM, 8 PM to 12 Midnight, Midnight to 4 AM, and 4 AM to 8 AM).

The PSQ is designed to evaluate sleep quality, ability to function, and the degree to which RLS symptoms interfere with sleep.

The PghSD assessed participant's previous night's sleep. Change from baseline was calculated as the Day 14 (in the evening), 15 (in the morning), and 16 (at Tmax of GEn and DPH) value minus the Baseline (Days -1 and 1) value. Latency to sleep onset (time to fall asleep) and wake time after sleep onset are expressed in minutes.

The PghSD assessed a participant's previous night's sleep. Change from baseline was calculated as the Day 14 (in the evening), 15 (in the morning after dose), and 16 (at Tmax)value minus the Baseline (Days -1 and 1) value. Total sleep time is expressed in hours.

The PghSD assessed a participant's previous night's sleep. Sleep quality was assessed using a Visual Analogue Scale (VAS). Participants indicated their sleep quality by marking a vertical line on a horizontal scale anchored by responses "very bad" and "very good." VAS score was determined by measuring the distance in millimeters (mm) from the left hand end of the line to the point that the participant marked. Scores ranged from 0 to 100 mm with higher scores indicating better sleep quality and lower scores indicating worse sleep quality.