Background and Purpose—Studies continue to reveal persistent gaps in stroke awareness despite existing stroke messages, especially when the length of time from message exposure increases. Therefore, there is a need to discover messages that promote long-term retention of stroke knowledge. We modified a standard stroke education poster using one health communications model, Extended Parallel Process, to assess its comparative effect on public stroke awareness and information retention.

Methods—This was a single blinded, randomized, pretest, posttest study using 2 age cohorts: younger (18 to 30 years) and older (50+ years). Stroke knowledge was measured by the 28-item Stroke Action Test taken before and after viewing either an Extended Parallel Process modified poster or a standard educational poster in widespread use and again 6 weeks later.

Results—Overall, there were 274 participants (222 younger and 52 older) with 139 randomly assigned to view the Extended Parallel Process poster and 135 assigned to view the standard poster. There was no significant difference (P>0.05) in the average Stroke Action Test score change between poster groups at all 3 testing intervals, although there was a nonsignificant greater drop in Stroke Action Test scores observed in the control group at the 6-week follow-up (-3.52 versus -2.60; P=0.46). The observed power for this difference was only 11% due to attrition of study participants (total 6-week follow-up, n=170). The younger group did significantly better on the Stroke Action Test from baseline to immediate posttest when viewing either poster (P<0.05).

Conclusions—A common stroke education poster modified according to the Extended Parallel Process model did not significantly increase stroke knowledge compared with a standard control. However, the Extended Parallel Process model may promote long-term stroke knowledge retention, although further studies are needed due to insufficient power from subject attrition.