Table 2.

Results from trials of audiovisual interventions to improve patient comprehension in informed consent

Source	Study country	N	Mean patient age (and range if specified)	Patients’ education	Procedure	Intervention	Elements of patient comprehension assessed	Comprehension assessment tool	Timing of patient comprehension assessment relative to informed consent consultation*	Risk of bias for patient comprehension outcome†	Results	Group favored‡
Egekeze et al. (2016)	USA	67	54.2 y	All patients had a maximum completed level of academic achievement of a high school diploma	Knee corticosteroid injection	Group 1 : control (10-minute informed consent discussion scripted at an eighth-grade reading level on the basis of information from the knee arthritis section of the patient education website OrthoInfo) Group 2: received the same verbal consent as the control group while watching a 10-minute animated knee anatomy video (played on silent; research staff member pointed at images in the video during the discussion) Group 3: received the same verbal consent as the control group while holding an anatomic knee model; each participant touched specified aspects of the model that corresponded with the discussion	Unclear/ not specified	14-item multiple choice questions in interview format with 20 minute time limit	Immediately	Some concerns for bias	Control: mean score 71% (10.0 out of 14) Group 2: mean score 74% (10.3 of 14) Group 3: mean score 84% (11.7 out of 14) P = 0.019	Group 3 > group 2 > control
Lin et al. (2018)	Taiwan	142	Not specified	15% less than high school, 37% high school, 48% college	Trauma-related debridement surgery	Educational video (~15 minutes duration) developed by a panel of experts describing the surgery, anesthesia, benefits, risks, alternatives, and post-op recovery using advanced 2D graphics, audio narrative, written subtitles and captions in addition to standard consent (verbal information plus written consent form with information about the surgery similar to that on the video plus educational session with health care provider) versus standard consent alone (control)	Risks, general knowledge about procedure	10-item multiple choice questionnaire	Immediately	Some concerns for bias	Mean knowledge score 72.57% intervention vs. 61.67% control, P < 0.001 Mean improvement in knowledge from baseline 18.71 (SD 16.44) intervention vs. 10.83 (SD 11.23) control, P = 0.001	Intervention
Huber et al. (2012)	Germany	220	63.4 y	8.9%, none or basic (missing school-leaving qualification or uncompleted professional training), 52.7%, higher (having passed senior technical college or university), 39.4%, medium (all remaining patients)	Radical prostatectomy	Computer-based multimedia tool (developed by an “interdisciplinary group” and tested with patients and “lay people” before completing the final version) with an interface allowing the consenting physician to navigate between and highlight portions of graphics, illustrations, videos, and pictures in place of standard physician consent using a written consent form containing the same information (control)	Risks	“Remembered quantity” of risks	Early	Some concerns for bias	2.3 (SD 1.2) intervention vs. 2.4 (SD 1.4) control	Neither
Baenninger et al. (2018)	Switzerland	113	35.3 y (range 19.7 - 57.1)	Not specified	Refractive excimer laser treatment for refractive ophthalmologic error	8-minute video of surgeon giving standard information and treating a patient plus further animations of the procedure in addition to conventional face-to-face consultation with a surgeon versus conventional face-to-face consultation with a surgeon alone (control)	Risks, general knowledge about procedure	25-item paper-based true/false questionnaire	Not specified	Some concerns for bias	22 out of 25 mean score for both intervention and control, P = 0.975	Neither
Vo et al. (2018)	USA	63	Not specified	Not specified	Cataract Surgery	American Academy of Ophthalmology cataract surgery education video (4 minutes, 9 seconds long) prior to traditional face-to-face counseling with a surgeon versus traditional face-to-face counseling with a surgeon alone (control)	Risks, benefits, alternatives, general knowledge about procedure	Self-administered questionnaire with yes/no and 5 point scale items	Immediately	Some concerns for bias	79.4% (SD 2.82%) intervention) vs. 79.3% (SD 3.39%) control, P = 0.99	Neither
Pallett a et al. (2018)	USA	120	42.8 y	0.8% less than 24.6% high school, 74.6% higher education	Hysterectomy	10-minute video developed by the study investigators with audio script, illustrations, and animations addressing 11 key aspects of the informed consent discussion plus standard physician counseling versus standard physician counseling covering the same 11 key aspects alone (control)	Risks, general knowledge about procedure	Questionnaire with true/false and multiple choice items; 4 versions with each subject given each version in a different order at 4 time points	Immediately and delayed	Some concerns for bias	Immediate: 15.1% improvement in score (SD 2.04%) intervention vs. 5.2% (SD 2.1%) control, P = 0.009 Delayed, day of surgery: 8.3% improvement in score (SD 2.3%) intervention vs. 1.2% (SD 2.01%) control, P = 0.02 Delayed, 6 weeks post consent: scores back to baseline for both groups	Intervention
Lattuca et al. (2018)	France	843	67.3 y	36% primary school, 48% secondary school, 16% university or higher	Coronary angiography	5-minute video with 3D animations developed for the study with content derived from the national information and consent form and approved by the scientific committee of the French Society of Cardiology displayed to each patient on an individual 10″ tablet in addition to standard consent (oral information and national standard written form) versus standard consent alone (control)	Risks, general knowledge about procedure	16-item questionnaire	Immediately	Some concerns for bias	Overall score 11.8 intervention out of 16 (SD 2.8) vs. 9.5 control out of 16 (SD 3.1), P < 0.001	Intervention
Zhang et al. (2017)	China	80	Not specified	66% primary education, 23% secondary education or higher	Cataract surgery	6-miute educational video based on a video from the American Academy of Ophthalmology that included visual teaching aids, animation, music, and a script written in Mandarin and Cantonese by an “expert in ophthalmological patient-information needs” in addition to traditional verbal consent and consent documents versus traditional verbal consent and consent documents alone (control)	Risks, benefits, alternatives, general knowledge about procedure	10-item yes/no questionnaire	Immediately	Some concerns for bias	Accuracy rate 80.2% intervention vs. 77.5% control, P = 0.386	Neither
Armstrong et al. (2010)	USA	84	59.0 y	1.2% 1st through 8th, 17.9% 9th through 12th, 23.8% 1-3 years college, 57.1% 4 or more years college	Skin shave and punch biopsy	Dermatologists “obtained informed consent for skin biopsies using an educational video” with actual footage of shave and punch biopsy procedures displayed on a portable device (unclear whether in place of or in addition to standard consent) versus traditional face-to-face consent with a dermatologist alone (control)	Risks, general knowledge about procedure	6-item multiple choice questionnaire	Immediately	Some concerns for bias	Knowledge score 1.55 out of 6 (SD 1.71) intervention vs. 1.12 out of 6 (SD 1.71) control, P = 0.259	Neither
Bowers et al. (2015)	Canada	93	60.9 y (range 19 - 89)	Not specified	Endovascular aneurysm repair, peripheral angioplasty, Hickman catheter, and peripherally inserted central catheter insertion	2 minute computer-generated video presented on an electronic tablet by a medical student with simplistic anatomical visuals and information about the procedure after traditional verbal consent versus traditional verbal consent alone (control)	Risks, general knowledge about procedure	5-item written true/false test	Not specified	Some concerns for bias	"Intervention group had higher total comprehension scores” (numbers not reported)	Intervention
Clark et al. (2011)	USA	50	38.5 y	36% did not complete high school, 32% completed high school, 24% with some college or trade school, 8% with some graduate school	Elective cholecystectomy	PowerPoint presentation with illustrations of cholelithiasis and laparoscopy cholecystectomy shown after standard informed consent (surgical benefits, risks, and complications explained “in the usual fashion” by general surgery residents using a checklist who had been trained for the study and monitored in a previous 10-patient pilot study) versus standard informed consent alone (control)	Risks, benefits, general knowledge about procedure	10-item true/false questionnaire	Not specified	Some concerns for bias	Correct response rate 66% intervention vs. 68% control, no P value provided	Neither
Mishra et al. (2010)	Scotland	84	66.6 y (range 62 - 71)	Not specified	Coronary artery bypass graft surgery	Group 1: control (standard informed consent consultation) Group 2: informed consent consultation audio-recorded then participants given a tape containing general information about CABG Group 3: informed consent consultation audio-recorded then participants given a tape recording of their own consultation interview Tapes were sent by mail with a letter encouraging patients to listen to them as many times as they wished	Unclear/ not specified	Validated 16-item questionnaire administered in person with each answer scored on a scale of 0 (inadequate) to 3 (very good)	Not specified	Some concerns for bias	Control: mean score 13.79 out of 48 (SD 5.354) Group 2: mean score 19.64 out of 48 (SD 3.451) Group 3: mean score 31.97 out of 48 (SD 5.922) P < 0.001	Group 3 > group 2 > control
Ham et al. (2016)	South Korea	40	66.9 y	37.5% did not complete high school, 32.5% completed high school, 30% university of more	High-performance system photoselective vaporization of the prostate	Multimedia presentation containing the same content as conventional consent forms but utilizing pictures, illustrations, animations, and videos without voiceover explained by a physician in place of conventional consent (verbal explanation plus written document) versus conventional consent alone (control)	Risks, alternatives, general knowledge about procedure	15-item questionnaire	Immediately	Some concerns for bias	Mean score 10.6 out of 15 (SD 2.8) intervention vs. 9.9 out of 15 (SD 2.3) control, P = 0.332	Neither
Tipotsch-Maca et al. (2016)	Austria	123	71 y (range 56 - 90)	15% passed graduation examination	Cataract surgery	Computer-animated video in addition to standard consent (standardized face-to-face discussion following a checklist plus information brochure) versus standard consent alone (control)	Risks, alternatives, general knowledge about procedure	10-item multiple choice questionnaire	Immediately	Some concerns for bias	Mean number of correct answers 8.2 out of 10 (SD 0.5) intervention vs. 7.2 our of 10 (SD 0.7) control	Intervention
Wysocki et al. (2012)	Poland	58	57.5 y	Not specified	Mastectomy	12-minute video with additional information adapted from the National Cancer Institute (www.cancer.gov) presented by a breast cancer survivor in addition to routine informed consent (non-standardized conversation with the attending surgeon, practical information from nurses, basic informed consent form) versus routine informed consent alone (control)	Alternatives, general knowledge about procedure	"Self-administered questionnaire”	Early and delayed	Some concerns for bias	No overall score reported; greater percentage of intervention group correctly answered a question regarding treatment options within 24 hours and 7 days post-op (P = 0.010 and 0.036, respectively) with no difference at 30 days post-op, and no difference between groups on two other questionnaire items	Neither
Choi et al. (2015)	South Korea	51	22.4 y (range 18 - 27)	19.6% up to secondary education, 80.4% postsecondary education	Impacted mandibular third molar removal	Narrated slideshow with simple illustrations created in PowerPoint by “personnel at the Korean Academy of Dental Science” including audio and visual cues plus standard informed consent document versus standard informed consent (verbal explanation plus Korean Dental Association Informed Consent document)	Risks	Open-ended questionnaire form assessing recall of risks	Delayed	High risk of bias	No overall score reported; intervention group showed improvement over control in recall of only 2 out of 8 individual risks, P < 0.05, no significant difference in recall of all other risks, P > 0.1	Neither
Ellett et al. (2014)	Australia	41	36.1 y (range 19 - 51)	3% primary, 20% secondary including year 10, 34% secondary years 11 and 12, 26% graduate degree, 8% postgraduate degree	Operative laparoscopy for investigation and treatment of pelvic pain	Routine, standardized surgical consent followed by a 15-minute educational multimedia module containing voice, script developed by the study authors, and 3D computer animations versus routine surgical consent alone (control)	Risks, benefits, general knowledge about procedure	14-item true/ false/ unsure questionnaire	Immediately and delayed	High risk of bias	Immediate: mean score 11.3 out of 14 (SD 0.49) intervention vs. 7.9 out of 14 (SD 0.50) on immediate testing, P < 0.001 Delayed: no difference	Intervention
Karan a et al. (2011)	India	60	63.1 y	Mean formal education in years: 3.0	Cataract surgery	24″ × 36″ poster displaying nine images in addition to scripted verbal informed consent read by a native Tamil speaker versus scripted verbal informed consent read by a native Tamil speaker alone (control)	Risks, benefits, general knowledge about procedure	Oral 11-item true/false/don’t know quiz	Immediately and early	High risk of bias	Immediate: mean score 8.17 out of 11 intervention vs. 8.13 out of 11 control, P = 0.9361 Within 24 hours: mean score 8.71 out of 11 intervention vs. 7.39 out of 11 control, P = 0.0049, and mean improvement in score 3.6 intervention vs. 1.3 control, P = 0.002	Intervention
Winter et al. (2016)	Australia	88	54 y	27% did not complete high school, 73% secondary education or above	Cystoscopy and ureteric stent insertion	7:07-minute educational video with cartoon animation presented on an electronic tablet versus standard verbal consent with “urology registrar”	Unclear/ not specified	True/false and multiple choice questionnaire	Not specified	High risk of bias	23.26 out of 32 intervention vs. 20.13 out of 32 control, P < 0.001 17.8% increase in score when standard verbal consent group was crossed over to the intervention, P < 0.001 No significant difference in score when intervention group was crossed over to the control, P = 0.621	Intervention
Sharma et al. (2018)	USA	101	Not specified	Not specified	Functional endoscopic sinus surgery	One pre-operative and one immediate post-operative visit were video-recorded; intervention group was given access to their recordings via secured internet server to watch at their discretion, control group was not given access to their recordings	Risks, general knowledge about procedure	Paper-based questionnaire with multiple choice and yes/no items	Delayed	High risk of bias	Accurate recall of risks 66% intervention vs. 63% control Correct answers to questions regarding extent of surgery 4.46 out of 5 intervention vs. 4.27 out of 5 control “Not statistically significant” (no P value given)	Neither
Wilhelm et al. (2009)	Germany	212	53.2 y	59.9% did not complete high school, 40.1% high school degree or higher	Laparoscopic cholecystectomy	26-minute DVD designed by the Institute of Media Informatics of the University of Munich and the Department of Surgery of the Technische Universtät of Munich with text, 3D computer animations, video sequences, audio commentary, and an “education dialogue” between a surgeon and actor posing as a patient in addition to standard informed consent with a surgeon versus standard informed consent with a surgeon alone (control)	Risks, general knowledge about procedure	25-item multiple choice questionnaire	Delayed	High risk of bias	Mean score 19.88 out of 25 intervention vs 17.58 out of 25 control	Intervention

^*Immediately: within 1 hour of informed consent consultation; early: >1 hour but <24 hours of informed consent consultation, delayed: ≥ 24 hours after informed consent consultation

^†Assessed using the Cochrane Risk of Bias 2.0 tool, see Table 7 for details

^‡If a study reported an improvement in patient comprehension on a single item or multiple items of the comprehension assessment but if overall score did not improve, we considered neither or no group to be favored