Protocol for studies involving the recording of electrodermal responses (skin conductance) from the hand

Transcription

1 1. Title Protocol for studies involving the recording of electrodermal responses (skin conductance) from the hand 2. Brief outline of nature and purpose of procedure Several research groups in psychiatry, experimental psychology and physiological sciences do research involving measurements of electrical activity from the surface of the skin. This is known as the recording of electrodermal activity (EDA), the skin conductance response (SCR) or historically, the galvanic skin response (GSR). EDA has been studied for more than 100 years using similar methodology and indexes the activity of the sympathetic nervous system. It is a simple method to employ and carries no significant risks to the participant. This protocol is intended to be used for studies where participants are adult volunteers. EDA recording is a class B invasive procedure and thus results in the ticking of a shaded box in section F of the CUREC Ethics Checklist. We do not anticipate that where participants are recruited by virtue of their experience of current or prior psychological symptoms (e.g. depression) that this raises any additional issues in relation to the use of EDA recording. Thus this protocol is equally applicable for studies of this nature. However it is possible that the inclusion of such participants may raise other ethical issues. This protocol does not seek to address these and independent ethical scrutiny or reference to other protocols and guidelines may be required. The EDA recording provides a measure of changes in the electrical conductance or resistance of the skin that originate primarily from movement of sweat within the eccrine sweat ducts. EDA fluctuates spontaneously and also in response to the presentation of stimuli which are novel, unexpected or significant, or by the omission of an expected response. A basic distinction can be made between tonic and phasic EDA. Phasic EDA refers to changes in EDA (increases or decreases in resistance/conductance) that are superimposed on a background tonic level of activity. EDA can be quantified in a number of ways. Sometimes researchers will be interested in spontaneous fluctuations in EDA (non-specific skin conductance responses NS-SCR) whilst at other times they will be interested in changes in skin conductance in response to the presentation of particular stimuli or the participant s conduct of particular activities (event-related SCR ER-SCR). A number of measurements of SCR can be derived. These include frequency over a particular recording period, amplitude (the mean amplitude averaged across trials where an ER-SCR is observed) and magnitude (the mean maximum amplitude averaged across all trials). These measures are derived through off-line analysis of data collected during experimental sessions. Usually a latency window of 1-4 seconds post-stimulus presentation is employed in order to identify skin conductance responses that are likely to originate from the stimulus presentation. On some occasions a longer post-stimulus window may be utilised, depending on the nature of the stimulus. In experimental paradigms, the SCR is usually recorded whilst people view stimuli, perform cognitive tasks or sit at rest. Recording of the SCR is achieved by measurement of current flow between two electrodes placed on the skin of the fingers or palm (see below for precise locations). A constant voltage is maintained between the two electrodes such that current flow reflects the recipricol of skin resistance. Electrode placement and preparation should typically take no more than 5 minutes. The participant is asked to wash their hands with a non-abrasive soap prior to electrode placement. Depending on the set-up employed, two electrodes will then be attached to either the volar surfaces of the medial phalanges, the volar surfaces of the distal phalanges or thenar and hypothenar eminences of the palms. Electrodes are usually attached to the non-dominant hand since this is less likely to be affected by cuts or callouses and since this leaves the dominant hand free to make responses (e.g. button presses). Silver-silver chloride cup electrodes are typically used. In order to establish electrical

2 contact between the skin surface and the electrodes, a unibase electrolyte paste is inserted into the cup electrodes, which can be attached to the skin surface either using double-sided adhesive collars, or in some custom made systems via specially designed Velcro pouches. Usually after the electrodes have been applied the participant will be asked to sit at rest for a few minutes to stabilise SCR activity before beginning cognitive tasks. 3. Training of research staff Training in application of electrodes and setting up the recording should be given by an experienced researcher, and no inexperienced person should be left in sole charge of an SCR study. 4. Methods for recruiting participants Participants for SCR studies are typically recruited via posters around the University (see example attached). It is acceptable to mention rewards in recruitment advertisements for this kind of study, where competent adults volunteer themselves to take part, and there is no significant risk to the participant other than boredom. 5. Information provided to participants The specific details provided to participants will vary depending on the study, but will always be on University headed paper and will always include: the name of the study the name(s) and status(es) (e.g. doctoral student) of the researchers carrying out the study and how to contact them the purpose and value of the study why potential participants are being invited to take part in the research (e.g. because they have or have not ever experienced particular psychological symptoms) what the study will involve for participants (description in lay language of all procedures including purposes, duration, location, frequency etc) that potential participants can ask questions about the study before they decide whether to participate that potential participants can choose whether they participate and, if they agree, they may withdraw from the study without penalty at any time by advising the researchers of this decision. (If the potential participants are students there should be particular reassurance that there is no academic penalty for non participation or withdrawal.) that the project has received ethics clearance through the University of Oxford s ethical approval process for research involving human participants who will have access to personal data provided, how the data will be stored; and what will happen to the data at the end of the project what benefits (direct or indirect) may accrue to the participants in the study what risks are involved in the study. The information sheet will also explain that the study carries no significant personal risk and that the data will be anonymised In addition, a verbal explanation will be given to all participants by the researcher conducting the

3 study. A draft information sheet is attached. 6. Consent of participants All participants sign a consent form which will always be on University headed paper and will always include: the name of the study the name and status (e.g. doctoral student) of the researcher collecting the information and how to contact him/her the purpose of the study declarations that the participant: has read the participant information sheet has had the opportunity to ask questions about the study and has received satisfactory answers to questions, and any additional details requested understands that s/he may withdraw from the study without penalty at any time by advising the researchers of this decision understands that this project has received ethics clearance through the University of Oxford s ethical approval process for research involving human participants understands who will have access to personal data provided, how the data will be stored; and what will happen to the data at the end of the project agrees to participate in this study. Participants will sign, print and date their names and the researchers who secure the consent will also sign, print and date their names. (see example attached) 7. Financial and other rewards to participants Participants are typically rewarded with payments or vouchers for music or books to compensate them for the time spent in the study. 8. Potential risks to participants/researchers/others and what will be done to minimise Risks to participants SCR recording has been used safely for many years, and we are aware of no cases of adverse events. During the session, participants are asked to indicate if they feel any discomfort, in which case the procedure is stopped. It is possible to pause the procedure if a participant needs to take a break or visit the bathroom, or if a fire alarm goes off. Skin conductance responses vary from individual to individual. Researchers undertake not to make any judgemental comments on the type of responses seen in individual participants, to avoid causing unnecessary anxiety. E.g. the researcher should not make a comment such as you ve only got very

4 small SCR responses. One consideration for researchers is hygiene: the sensors and instruments used to apply gel should be disinfected after each use. Risks to researchers Again, the main way to avoid risk is to adhere to a regime of hygiene. Hands are washed after any contact with the participant. 9. Monitoring and reporting of adverse or unforeseen events If a participant should become unwell during the test session, the session will be terminated. Such a case would be reported in the Departmental Safety Book. 10. Communication of results 11. Duty of care issues/confidentiality 12. Data Protection issues Each participant is given a code number, and this, rather than the name, is used to label all data from the study, including computerised SCR files and any paper records. If it is necessary to retain any personal information (e.g. contact details in the case that participants may be re-tested) the key linking codes to personal details will be kept in a locked filing cabinet. Data will be stored for a period of 10 years in accordance with guidelines imposed by major funding bodies. At the end of this time it will be destroyed. 13. Further information

5 Sample information sheet: on headed paper with contact details of researcher in header Research Study: WHAT EFFECT DOES MEDITATION HAVE ON INFORMATION PROCESSING? You are being invited to take part in a research study. Before you decide, it is important for you to understand why the research is being done and what it will involve. Please take time to read the following information carefully, and discuss it with others if you wish. Ask us if there is anything that is not clear or you would like more information. Take time to decide whether or not you wish to take part. Thank you for reading this. What is the purpose of this study? We are interested to find out more about the effects of short periods of meditation on the way that people process information. In order to do this we will monitor people s physiological responses (the electrical conductance of the skin on the hand) before and after a period of meditation, or a comparison activity, and whilst people complete a number of short computer-based tasks. What will happen if I take part? You would be invited to the Department of Psychiatry for testing. We would measure the electrical conductance of the skin on the palm of your non-dominant hand both whilst you sat resting and whilst you completed several short computer-based tasks. We would also ask you to complete a number of questionnaires during the session. The procedure for measuring skin conductance is harmless and painless and carries no significant risk to participants. The experimenter would first ask you to wash your hands with soap and water. They would then place two metal contacts (electrode sensors) on your palm. These would be attached to the skin with double-sided adhesive collars which could easily be removed at the end of the session (like a plaster). To make electrical contact, a gel would be placed under each metal contact. It is very unlikely that you would experience any discomfort during the placing of the electrode sensors. If however you did experience discomfort, we would terminate the experiment immediately without this having any negative consequences for you. The gel used to make the electrical contact is water based with a similar salt composition to sweat and washes away easily. Once the set-up is completed, you would be asked sit in a comfortable armchair and rest for ten minutes. A computer screen would then be wheeled in front of the chair. Words would be presented on the screen one at a time and you would be asked to make a judgement about each word and press a button to indicate your response. Following the task you would be asked to remain seated and you would be given a set of headphones to wear. You would then be asked to listen to instructions from a CD and try to focus completely on either your emotions or your experiences and sensations. We will also ask you to rate your mood several times over the course of the experiment and to complete a couple of questionnaires. Those who take part are reimbursed for their travel expenses and time. (It is permissible here to mention the amount of reimbursement)

6 What happens to the results of the research study? All the information we collect is kept strictly confidential. Data and test results will be identified by a code number only, and are kept in a locked filing cabinet or on passwordprotected computers. We plan to publish the results in a scientific journal, but would not normally give feedback about results to individual participants. Information about published papers can be found on our website ( Who is organising, funding and monitoring the research? The research is organised by xxx of Oxford University, and is funded by thewellcome Trust. This study has received ethics clearance through the University of Oxford s ethical approval process for research involving human participants. How to contact us: If you would be willing to take part in this study, or would like to discuss the research further with someone, please contact xx (doctoral student) at the following address/phone number: Thank you! Department of Psychiatry Warneford Hospital Headington Oxford OX3 9DU mood.project@psych.ox.ac.uk

7 Presented on Headed Paper CONSENT FORM Title of project: The purpose of this study [One line description of project here] Name of Responsible Investigators: [Please initial] Yes No 1. Have you read the Participant Information Sheet? 2. Have you had an opportunity to ask questions and discuss this study? 3. Have you received satisfactory answers to all your questions? 4. Have you received enough information about the study? 5. Who has explained the study to you? Dr/Mr/Mrs/Ms 6. Do you understand you are free to leave the study: at any time without having to give a reason for leaving and without affecting your future medical care? 7. Do you understand that this study has been approved by University of Oxford Central University Research Ethics Committee? 8. Do you understand that personal data will be identified using only a number code, will be accessed only by members of the research team and will be destroyed after a period of 10 years. 9. Are you aware that all information will be kept strictly confidential within the limits of the law and except in the rare circumstances in which it is judged that you or someone else is at immediate risk of serious harm? 10. Do you agree to take part in this study? Signature of Participant Date [NAME IN BLOCK LETTERS] Signature of Researcher Date [NAME IN BLOCK LETTERS]