We reviewed the evidence about the effect of audio-visual presentation of information used in the informed consent process for people considering entering a clinical trial. We compared this with the usual informed consent information (either written and/or verbal) and placebo (sham) audio-visual information.
Before taking part in a clinical trial, potential participants must be provided with detailed information, such as what they will be asked to do and any possible benefits or harms. Once they understand what is involved, and if they are happy to take part, they usually sign a consent form. This process is known as 'informed consent'. The problem is that consent forms use technical language that can be hard to for the average person to understand. Sometimes people agree to take part in a clinical trial even though they are unsure what is involved. Presenting the consent form information in an audio-visual format (for example, on a computer or DVD) might improve the informed consent process.
We searched for studies of audio-visual informed consent interventions which allocated people to an experimental or control group by a random or quasi-random process, published up until June 2012. We found 16 studies, involving a total of 1884 people. Nine studies included people considering real clinical trials, eight included people asked to imagine participating in a clinical trial (a hypothetical trial), with one including both. Most of the studies were conducted in the United States.
People were considering (or imagined considering) participation in a range of different clinical trials, including those testing cancer treatments and drugs for mental health problems. The audio-visual informed consent information was presented on computers, DVDs, videos and CD-ROMs. They included voice overs by professional actors, real patients talking about their experiences and a combination of words, pictures and audio to explain the technical concepts. In some studies, people also received the usual written informed consent forms and/or a face-to-face explanation by the study staff.
There is low to very low quality evidence that audio-visual consent interventions may slightly improve knowledge or understanding of the parent trial, but may make little or no difference to rate of participation or willingness to participate. Audio-visual presentation may improve participation satisfaction with the information provided. However its effect on satisfaction with other aspects of the process is not clear. There is not enough evidence to draw conclusions about anxiety arising from audio-visual informed consent. There is conflicting, very low quality evidence about whether audio-visual interventions take more or less time to administer, and no study measured researcher satisfaction with the informed consent process, nor ease of use.
We do not believe that any studies were funded by organisations with a vested interest in the results.
Quality of the evidence
The quality of evidence from real clinical trials was low, and from hypothetical clinical studies, very low. This is because of the small number of people in the studies, and some issues in the way they were conducted. If the next update of this review includes more studies of audio-visual informed consent presentation, it could change the results of this review.
The value of audio-visual interventions as a tool for helping to enhance the informed consent process for people considering participating in clinical trials remains largely unclear, although trends are emerging with regard to improvements in knowledge and satisfaction. Many relevant outcomes have not been evaluated in randomised trials. Triallists should continue to explore innovative methods of providing information to potential trial participants during the informed consent process, mindful of the range of outcomes that the intervention should be designed to achieve, and balancing the resource implications of intervention development and delivery against the purported benefits of any intervention.
More trials, adhering to CONSORT standards, and conducted in settings and populations underserved in this review, i.e. low- and middle-income countries and people with low literacy, would strengthen the results of this review and broaden its applicability. Assessing process measures, such as time taken to administer the intervention and researcher satisfaction, would inform the implementation of audio-visual consent materials.
Informed consent is a critical component of clinical research. Different methods of presenting information to potential participants of clinical trials may improve the informed consent process. Audio-visual interventions (presented, for example, on the Internet or on DVD) are one such method. We updated a 2008 review of the effects of these interventions for informed consent for trial participation.
To assess the effects of audio-visual information interventions regarding informed consent compared with standard information or placebo audio-visual interventions regarding informed consent for potential clinical trial participants, in terms of their understanding, satisfaction, willingness to participate, and anxiety or other psychological distress.
We searched: the Cochrane Central Register of Controlled Trials (CENTRAL), The Cochrane Library, issue 6, 2012; MEDLINE (OvidSP) (1946 to 13 June 2012); EMBASE (OvidSP) (1947 to 12 June 2012); PsycINFO (OvidSP) (1806 to June week 1 2012); CINAHL (EbscoHOST) (1981 to 27 June 2012); Current Contents (OvidSP) (1993 Week 27 to 2012 Week 26); and ERIC (Proquest) (searched 27 June 2012). We also searched reference lists of included studies and relevant review articles, and contacted study authors and experts. There were no language restrictions.
We included randomised and quasi-randomised controlled trials comparing audio-visual information alone, or in conjunction with standard forms of information provision (such as written or verbal information), with standard forms of information provision or placebo audio-visual information, in the informed consent process for clinical trials. Trials involved individuals or their guardians asked to consider participating in a real or hypothetical clinical study. (In the earlier version of this review we only included studies evaluating informed consent interventions for real studies).
Two authors independently assessed studies for inclusion and extracted data. We synthesised the findings using meta-analysis, where possible, and narrative synthesis of results. We assessed the risk of bias of individual studies and considered the impact of the quality of the overall evidence on the strength of the results.
We included 16 studies involving data from 1884 participants. Nine studies included participants considering real clinical trials, and eight included participants considering hypothetical clinical trials, with one including both. All studies were conducted in high-income countries.
There is still much uncertainty about the effect of audio-visual informed consent interventions on a range of patient outcomes. However, when considered across comparisons, we found low to very low quality evidence that such interventions may slightly improve knowledge or understanding of the parent trial, but may make little or no difference to rate of participation or willingness to participate. Audio-visual presentation of informed consent may improve participant satisfaction with the consent information provided. However its effect on satisfaction with other aspects of the process is not clear. There is insufficient evidence to draw conclusions about anxiety arising from audio-visual informed consent. We found conflicting, very low quality evidence about whether audio-visual interventions took more or less time to administer. No study measured researcher satisfaction with the informed consent process, nor ease of use.
The evidence from real clinical trials was rated as low quality for most outcomes, and for hypothetical studies, very low. We note, however, that this was in large part due to poor study reporting, the hypothetical nature of some studies and low participant numbers, rather than inconsistent results between studies or confirmed poor trial quality. We do not believe that any studies were funded by organisations with a vested interest in the results.