Prior notification of trial participants by newsletter increased response rates: a randomized controlled trial.

OBJECTIVE: To assess the effectiveness of prenotification using a newsletter to increase questionnaire response rates within a randomized controlled trial (RCT). STUDY DESIGN AND SETTING: An RCT set within the context of the Medical Research Council's SCOOP trial of screening older women for fracture risk. RESULTS: A subsample of SCOOP participants were randomized in equal numbers to receive a newsletter approximately 6 weeks before the follow-up questionnaire or no newsletter. Of the 1,342 participants in the newsletter group, 1,291 (96.2%) returned their 24-month follow-up questionnaire compared with 1,271 of the 1,344 participants who were not allocated to receive the newsletter (94.6%). The difference of 1.6% was statistically significant (P=0.05), with an odds ratio (OR) of 1.45 (95% confidence interval [CI]: 1.01, 2.10). The newsletter and no newsletter groups required a similar number of reminders (OR 0.88, 95% CI: 0.73, 1.06), had a similar number with a complete primary outcome (OR 0.95, 95% CI: 0.57, 1.58), and took a similar time to respond (log rank 1.30, P=0.25). CONCLUSIONS: This study supports previous research that suggests that prenotification increases survey response rate: albeit a small absolute increase. No previous study has shown this to be so within the context of patients enrolled within an RCT. Trials that use newsletters to keep their participants informed of the study's progress should use the newsletter as a prenotification device as this will increase overall response rates.

Processing emotion from the eyes: a divided visual field and ERP study.

The right cerebral hemisphere is preferentially involved in recognising at least some facial expressions of emotion. We investigated whether there is a laterality effect in judging emotions from the eyes. In one task a pair of emotionally expressive eyes presented in central vision had to be physically matched to a subsequently presented set of eyes in one or other visual hemifield (eyes condition). In the second task a word was presented centrally followed by a set of eyes to left or right hemifield and the participant had to decide whether the word correctly described the emotion portrayed by the laterally presented set of eyes (word condition). Participants were a group of undergraduate students and a group of older volunteers (> 50). There was no visual hemifield difference in accuracy or raw response times in either task for either group, but log-transformed times showed an overall left hemifield advantage. Contrary to the right hemisphere ageing hypothesis, older participants showed no evidence of a relative right hemisphere decline in performance on the tasks. In the younger group mean peak amplitude of the N170 component of the EEG at lateral posterior electrode sites was significantly greater over the right hemisphere (T6/PO2) than the left (T5/PO1) in both the perceptual recognition task and the emotional judgement task. It was significantly greater for the task of judging emotion than in the eyes-matching task. In future it would be useful to combine electrophysiological techniques with lateralised visual input in studying lateralisation of emotion with older as well as younger participants.