Our sense of touch is vital for interacting with other people, and the world around us.

This study aims to improve our understanding of how touch is encoded by nerve fibres in the skin. We can do this using a technique called microneurography, which allows us to safely record signals directly from human nerves using very thin needle electrodes (sensors), whilst our participants are awake and comfortable, and can tell us what they feel.

For this experiment, we will be studying nerves in the Arm & Hand. This is what we call our region of interest. The nerves we target will be the: Antebrachial, Radial, or Median Nerves.

During recording, different types of touch, or tactile stimulation, will be applied to this region – this will include manual touch (by hand), brushing, indentation with a range of probes, and stimulation using computer-controlled stimulation devices which can deliver touch at precise forces and speeds.

The responses we record will teach us more about the touch system – particularly the system that perceives the kind of gentle touch that is important in social and caring contexts – and may also inform the development of tactile stimulation devices like the ones we use – which could in future be used to deliver touch-based therapy that is supported by neuroscientific evidence. The data collected may also contribute to student projects, which are conducted as part of a degree programme.

Please carefully read the information below, which tells you all about the study,

and what to expect if you choose to take part.

 You do not have to take part if you do not want to.

If you are interested in participating, please contact Adarsh Makdani (a.makdani@ljmu.ac.uk)

You have been invited because you already indicated an interest in our research, or because we reasonably believe you would be interested in taking part. If you meet the study criteria, we would like to hear from you.

• You are aged under 18.
• You cannot comfortably sit still for the duration of the experiment (approx. 4 hours).
• You have undergone microneurography on the same nerve in the last 3 months.
• You have nerve damage or neuropathy affecting nerves in the region of interest.
• You have a pacemaker, or any other implants sensitive to small electrical currents.
• You are or may be pregnant.
• You have a bleeding / blood-clotting disorder, such as haemophilia.
• You have a severe phobia of needles, or a history of fainting during blood tests or vaccinations.
• You have a severe allergy to medical tape or sticking plasters.
• You have severe eczema, dermatitis, or sensitive skin in the region of interest.
• You have a contagious skin, respiratory, or blood-borne infection.
• You have been ingesting alcohol, caffeine, or a lot of liquid on the day of the experiment.
• You are feeling unwell, or have any COVID-19 symptoms on the day of testing.

We have set these criteria for the safety of our participants and our research team.

If you have any questions or concerns about taking part, please get in touch.

If you would like to, you can also arrange to visit the lab and see the equipment in advance.

No. You can ask questions about the research before deciding whether to take part. If you do not want to take part that is OK.

You can withdraw at any time, without giving a reason, but we may need to keep information about you that we already have.

For questions about your data, please see the Data Protection section.

If you choose to take part, you will be invited to book one session at a mutually convenient date and time.

Testing primarily takes place in our lab in the Tom Reilly Building, at Liverpool John Moores University’s Byrom Street Campus in Liverpool. A testing session will typically last between 3 to 5 hours, depending on how well the recording is going.

• On the day, you will typically meet 2 or more members of the research team, who will be helping to conduct the study.
• When you arrive, we will take some time to go over this information sheet, in particular the exclusion criteria and study procedure. You will have the opportunity to discuss any concerns, and then you will be asked to complete a consent form, and health questionnaire which will help us identify any potential reasons why you should not take part, or where we might need to adapt our protocol. We then offer all participants a toilet break.
• When you are ready, you will be asked to sit in our adjustable chair. We will take some time to make you as comfortable as possible, whilst ensuring we have maximum access to the region of interest for this experiment – your ARM & HAND on your LEFT or RIGHT side, as appropriate.
• We will use a mouldable cushion to support you. We may also use an ultrasound imaging machine (like the one used in hospitals) to help us find the best position. Once we have achieved a good position for you, and us, we will attach & connect the sensors and cables needed to make our nerve recordings – the sensors we attach to you are self-adhesive (like plasters) or secured using medical tape.

From this point on, we will ask you to sit as still as possible.

The main technique we use is called Microneurography, which will allow us to record activity from your nerves whilst you are awake and comfortable.

• To do this, we will need to insert two 0.2 mm diameter needle electrodes through the skin – these are very fine, like acupuncture needles (about the thickness of 2 human hairs), and these act as sensors for the nerve signals. We will clean your skin with a sterile swab but won’t use anaesthetic as the needles are so fine it is often painless, or at most you will feel a fleeting sharp pinch. The first is inserted only a couple of millimetres into the skin and shouldn’t need to be moved. The other needle is our active electrode, and this will be guided through the skin and into the underlying target nerve. Depending on the nerve we are targeting, we may need to use very weak electrical pulses sent through the electrode, or ultrasound imaging to help us find our way into the nerve. This process should not be painful but may be mildly uncomfortable for short periods. We will always go at your pace and will use the sensations you tell us about to guide us.
• Once the electrode is in the nerve, we would expect to see “mass” activity – bio-electrical signals from many nerve cells (neurons) at once. These signals are the nerve impulses which are travelling to your spinal cord. They might be spontaneous, or in response to something, like a touch to skin. For our experiments, we need to isolate the signals from single neurons from the thousands of cells bundled together.
• To help us isolate a single neuron, we will stimulate the skin of the region of interest (using tactile stimulation such as gentle touch with a hand, or brushing), and adjust the position of the recording electrode in small steps, until a signal from a single neuron stands out from the noise.
• When we have a good signal, we will also try to localise the specific area that the neuron innervates – i.e. where on the skin it responds to touch the most. This is the receptive field. We will mark the receptive field using a marker and take measurements (using a tape measure) including the size of the receptive field, and the distance from the recording electrode.

We cannot predict what kind of neuron we will find, or where the receptive field will be, so our protocol is flexible. We will use a combination of standardised stimuli on the receptive field to evoke and record a response – this will include some or all of:

• Gentle, manual touch with the hand, such as tapping, pressure, and skin stretch.
• Indentation with nylon probes that are calibrated to apply specific forces ranging from imperceptibly low (~0.008 grams) to high (~300grams).
• Soft and rough brushes that we move across the receptive field at different speeds e.g. approx. 5 strokes with a make-up brush vs. a hair-dye brush, at 3cm/s and 30cm/s speeds.
• Computer-controlled tactile stimulation devices, such as the Rotary Tactile Stimulator (RTS) developed by DancerDesign in the UK.

• Some stimuli will need to be repeated a few times to capture enough responses for statistical analysis. The response data will allow us to identify and characterise the neuron(s) we are recording from. Each type of stimulation / stimulator will be explained to you in detail before we proceed. Nothing is done without your agreement. Some of the stimuli may be temporarily unpleasant (or mildly painful) when applied to the receptive field (such as the higher force nylon probes) - it is important that we study and compare responses to these types of touch as well, however our primary focus in this study is on gentle touch. All our procedures are extensively tested, and equipment is well maintained, and calibrated to safety limits.
• You will be encouraged to talk about your sensations as your perceptual experiences are just as important as the recordings. So that we can match signal to sensation, we may also ask you specific questions about the stimuli we use during or after the recording – this could include: rating the intensity of the sensation on a scale, picking descriptors to characterise the sensation from a standardised list (e.g. Touch Perception Task, McGill Pain Questionnaire), or being asked to give a description in your own words. Please remember, you have the right to decline to answer any questions you do not want to. We will always be happy to answer questions.
• We may need to take audio / video recordings or photographs of the procedures, and of the receptive field markings on your skin. We will explain what is being captured and why. Some photos and videos are required for data analysis – e.g. the shape and nature of the receptive fields, or to record the timing of stimulus and response. Other photos and videos may be captured to help with publication & dissemination of the research. We typically frame any photos or videos to avoid capturing identifying features. Where this is not possible, we would mask any identifying features prior to publication.

During the experiment you will be able to hear the nerve impulses that we are recording on a loudspeaker, and see them on screen in real-time, which is an exciting experience if you’re interested in neuroscience. We are happy to discuss the recordings with you, but this is not a diagnostic procedure, and we can’t draw any conclusions from individual recordings.

• Once we have recorded all that we can from any one neuron, if we have time and you are happy to continue, we will repeat our search process to find another single neuron.
• When the electrode is recording from the nerve, you should think of it as a critical period and stay as still and relaxed as possible. Outside of the critical period, you can make small movements to prevent fatigue.
• If you feel any strong or prolonged pain, if you need the toilet, have just had enough or need to stop for any reason, at any time, please let us know. We will safely remove the electrodes and sensors, and stop the experiment. Please note, once we remove the electrodes, we don’t tend to resume the session.

We hope you will be comfortable with the investigators recording videos and photographs of the procedure, the receptive field, and application of the tactile stimulation. You are free to ask us to stop any recording / photography at any time.

We will advise you in advance if any videos / photos are considered essential for analysis, and if stopping recording or photography would also require you to withdraw your participation.

With your explicit consent, photographs and videos taken of you may be used in the final report and any further outputs. Please notify the investigator if you require any restrictions on the use or availability of photographs or recordings at the time or in the future. Your name will not be attributed, however there is a chance that someone may recognise your image or voice. It is therefore important to take some time to think if there would be any implications for you if someone recognised your voice before you decide to consent to this.

Participating in the research is not anticipated to cause you any disadvantages or prolonged discomfort. Thousands of microneurography experiments have been conducted since 1965, with very few adverse reports.

However, as it is a minimally invasive procedure, there is the potential for side effects, which are discussed below. Where we report a side effect as “Rare” or “Very Rare”, it can be assumed that the side effect has never been reported.

• Transient Paraesthesia – Common: Some participants may feel a travelling sensation, tingling or pins-and-needles in the region of interest, during the recording, or afterwards if pressure is applied to needle insertion site. The sensations are short-lasting or transient, and insertion site is mildly sensitive to impact or pressure for 1 to 14 days.
• Fainting – Uncommon: Like with blood tests and vaccinations, people can feel faint or nauseous. This is an autonomic response and sometimes can’t be helped. If you feel unwell during the study, please tell us. We will pause and give you the opportunity to recover. If you continue to feel unwell, faint, or are sick, we will stop the experiment.
• Bleeding – Uncommon: Unlike needles used for blood tests, the thin needle electrodes are not designed to penetrate blood vessels. We also use anatomical markers to avoid blood vessels during insertion. No internal bleeding or blood vessel damage has ever been recorded. Uncommonly, participants may see a single drop of blood at the insertion site when the recording needle is removed. Bruising is rare.
• Mechanical Nerve Damage – Very Rare: The electrode may deform some neurons in the nerve, but they will regain their original positions when it is removed. There is no evidence of harm, however it is possible that a few cells of the thousands in the nerve bundle are temporarily damaged by this procedure. It is well known that such damage is quickly overcome (Seddon & Sunderland peripheral nerve injury classifications: I & II), however, as a precaution against damage and fatigue we do not study the same nerve more than once in 3 months.
• Infection - Very Rare: The electrodes are sterilized, and the research team is well trained. Infections have never been seen after these experiments. The risk for infection during these experiments is the same as or lower than the risk during a blood test.

If you do experience these, or any other side effects, or are concerned by anything you experience, please let us know. We will follow up via email after the experiment as it’s really important that we keep a record of people’s experiences.

There are no direct benefits to you. However, you will have the unique opportunity to see and hear your nerves in action!

This is one of the few labs in the world that uses microneurography to target individual neurons, and it is an opportunity to participate in pioneering neuroscience research. You are welcome to take photos and videos to document your experience, and share them with friends and family.

You will also be contributing significantly towards our understanding of peripheral nerve function, and our specifically the touch system – and all its implications for human interactions. You are also supporting the development of tactile stimulation devices like the ones we use – which could in future be used to deliver touch-based therapy that is supported by neuroscientific evidence.

You will receive up to £50 in Amazon shopping vouchers per session (depending on the length of the session), to cover your time and expenses.

• The information you provide as part of the study is the study data. Any study data from which you can be identified (e.g. from identifiers such as your name, date of birth, audio recording etc.), is known as personal data.
• Your participation in this study will involve the collection/use of personal data. Study data collected/used will also include more sensitive categories of personal data (special category personal data) relating to your health.
• We will keep personal data safe and secure. People who do not need to know who you are will not be able to see your name, contact details. We will limit access to your health data, and other personal data.

Personal data collected will include:

• Contact details. With your agreement, we would also like to store your contact details so that you may be contacted about future opportunities to participate in research studies.
• A record of consent (which will include your name).
• Study data. We will use a code/pseudonym so that you cannot be directly identified from the data. Study data will include photos and video recordings (which may include your voice and/or image).
• Study data / records of consent / contact details will be kept for at least 3 years after the study has finished, or as long as required to satisfy requirements for dissemination of research findings. If you agree to take part in this study, you will also have the option to take part in future research using your data saved from this study – such as future microneurography studies.
• Data will be stored securely on LJMU approved secure storage facilities, such as Microsoft OneDrive, or ctera FileStore, with strict access controls applied to any personal data. Physical data will be locked in secure on-site storage.
• We will write our reports in a way that no-one can work out that you took part in the study.

We are happy to discuss the recordings with you, but this is not a diagnostic procedure, and we can’t draw any conclusions from individual recordings. The investigator will not suggest the presence or absence of diagnosable conditions.

The study is not a clinical or personal assessment and the investigators cannot provide meaningful individual assessments.

If the investigator suspects they have found something unexpected, they may suggest that you to seek appropriate advice.

This study is organised by Liverpool John Moores University.

If you have a concern about any aspect of this study, please contact the study lead at LJMU:

Adarsh Makdani (a.makdani@ljmu.ac.uk). We will do our best to answer your query within 10 working days.

If you remain unhappy or wish to make a formal complaint, please contact the Chair of the Research Ethics Committee at Liverpool John Moores University who will seek to resolve the matter as soon as possible:

• Email: FullReviewUREC@ljmu.ac.uk;
• Tel: 0151 231 2121;
• Address: Research Innovation Services, Liverpool John Moores University, Exchange Station, Liverpool L2 2QP

Liverpool John Moores University is the data controller with respect to your personal data. Information about your rights with respect to your personal data is available from:

https://www.ljmu.ac.uk/legal/privacy-and-cookies/external-stakeholders-privacy-policy/research-participants-privacy-notice

You can also ask one of the study team, or contact us:

Contact details

Principal Investigator: Adarsh Makdani

LJMU Email address: a.makdani@ljmu.ac.uk

LJMU School/faculty: School of Psychology

LJMU telephone number: 0151 904 6348