Roflumilast and Donepezil to Reverse Scopolamine Induced Cognitive Deficits in Healthy Adults

VRM measures the ability to encode and subsequently retrieve verbal information. This task begins with the first presentation phase in which 18 words are shown in turn on the screen. The participant is then asked to recall as many words as possible during the first immediate recall phase. The same 18 words are then shown in a second presentation phase which is followed by a second immediate recall phase. After a delay of approximately 20-30 minutes, a delayed recall stage is completed. The possible range of correct responses is 0 (worst) to 18 (best). Higher number of correct responses in the test indicates a better outcome. A negative change from baseline indicates a worsening of the score.

PAL assesses visuospatial associative learning and memory. Boxes are displayed on the screen and open in a randomised order to reveal a number of patterns. The patterns are then displayed in the middle of the screen, one at a time, and the participant must touch the box where the pattern was originally located. If the participant makes an error, the patterns are re-presented to remind the participant of their locations. If the participant has not responded correctly within six attempts, ie, one presentation and five re-presentations, the task is terminated. As the task progresses the difficulty level increases with the number of patterns to be remembered. For participants who fail to complete all levels, an adjusted total is calculated that takes into account errors predicted in the stages that were not attempted. The possible range for total errors is 0 (best) to 91 (worst). Fewer number of errors in the test indicates a better outcome.

RVP is a task of continuous performance and visual sustained attention. The task consists of a 2-minute practice stage and a 7-minute assessed stage. There is a white box in the centre of the screen in which single digits from 2 to 9 appear one at a time in a pseudo-random order at a rate of 100 digits per minute. Participants must detect target sequences of digits (2-4-6, 3-5-7, and 4-6-8) and touch a button when they see the last digit of a target sequence. Nine target sequences appear every 100 numbers. A prime (A') is a signal detection measure that reflects target sensitivity regardless of the participant's tendency, or bias, to respond. Detection sensitivity for RVP A' prime: 0 to 1. Lower numbers in the test indicates worsening in the performance.

RVP is a task of continuous performance and visual sustained attention. The task consists of a 2-minute practice stage and a 7-minute assessed stage. There is a white box in the centre of the screen in which single digits from 2 to 9 appear one at a time in a pseudo-random order at a rate of 100 digits per minute. Participants must detect target sequences of digits (2-4-6, 3-5-7, and 4-6-8) and touch a button when they see the last digit of a target sequence. Nine target sequences appear every 100 numbers. Assessment will be based on a median latency. The possible range for RVP median latency is 100 (worst) to 1900 (best). Higher number in the test indicates a better outcome. "Median latency" is a measure captured by computerized test measure and given as "one" time value (between 100 and 1900). The "mean" of these values is presented.

SWM assesses the ability to retain spatial information and manipulate it in working memory. In this task, colored boxes are shown on the screen, and participants must search for blue tokens by touching the colored boxes to open them. When the blue token has been found the participant has to place the token in the black column ('home') on the right-hand side of the screen by touching this area. The participant must not return to a box where a token has previously been found. The task becomes more difficult as the number of boxes increases (one trial at each of 6-box and 8-box stages; three trials at each of 10-box and 12-box stages). Between Errors is the total number of times the participant revisits a box in which a token has previously been found in the same problem. The possible range of errors is 0 (best) to 1040 (worst). Lower number of errors in the test indicates a better outcome.

An Adverse Event (AE) is defined as any untoward medical occurrence in a clinical investigation participant administered a drug; it does not necessarily have to have a causal relationship with this treatment. An AE can therefore be any unfavorable and unintended sign (eg, a clinically significant abnormal laboratory finding), symptom, or disease temporally associated with the use of a drug, whether or not it is considered related to the drug. A TEAE is defined as any adverse event, regardless of relationship to study drug that occurs or worsens after the first dose of study drug and no more than 14 days after the last dose of study drug.

The percentage of participants with any markedly abnormal standard safety laboratory values, including hematology, serum chemistries, and urinalysis. LLN=lower limit of normal. ULN=upper limit of normal.

The percentage of participants who meet markedly abnormal criteria for vital signs, including oral body temperature, respiration rate, pulse, and resting blood pressure and after standing.

The percentage of participants who meet markedly abnormal criteria specified by the protocol and statistical analysis plan=abnormal clinically significant.