Condition category
Signs and Symptoms
Date applied
Date assigned
Last edited
Prospectively registered
Overall trial status
Recruitment status

Plain English Summary

Background and study aims
This study aims to discover if we can compare the pain felt by patients with a measurement of how their faces move. Facial movements will be assessed using muscle activity sensors worn like a pair of glasses/goggles that measure underlying muscle activity. Past studies show facial expression is sensitive to the intensity of pain. Laboratory studies looking at pain in volunteers suggest facial electromyography (EMG) to measure muscle activity could be a useful tool to determine the pain an individual is suffering. This may have particular relevance to patients where communication is limited such as patients with dementia.

Who can participate?
Patients aged 18 and over requiring hand surgery under local anaesthetic at the Queen Victoria Hospital

What does the study involve?
Whilst they are receiving the anaesthetic injection the participant’s facial muscle response is recorded non-invasively using specialized goggles containing muscle sensors. Simultaneously the participant’s experience of pain is recorded using a self-reported visual analogue score (VAS). Pain expectation is also considered, and anxiety traits and status are assessed before the intervention.

What are the possible benefits and risks of participating?
The results will further the scientific understanding of facial EMG responses and may benefit patients in the future who are unable to communicate with their clinicians. Furthermore patients are often keen to be involved in research as it gives them an opportunity to 'give back' to the healthcare service that cares for them. Participants may feel that completing questionnaires are laborious or intrusive. For this reason, the questionnaires used have been carefully selected to minimise the amount of time demanded of patients and in order to only address pertinent questions. During Patient and Public Involvement (PPI) consultation survey gathered for the purpose of the study patients were happy to have additional monitoring in place during their routine clinical procedure. A local anaesthetic injection is painful but is necessary for surgery to take place. The participants will not be subjected to any additional painful procedures.

Where is the study run from?
Queen Victoria Hospital (UK)

When is the study starting and how long is it expected to run for?
June 2019 to June 2021

Who is funding the study?
National Institute for Health Research (NIHR) (UK)

Who is the main contact?
Mr Julian Giles

Trial website

Contact information



Primary contact

Mr Julian Giles


Contact details

Queen Victoria Hospital
Holtye Road
East Grinstead
RH19 3DZ
United Kingdom
+44 (0)1342 314000

Additional identifiers

EudraCT number

Nil known number

Nil known

Protocol/serial number


Study information

Scientific title

A comparison of facial muscle responses with reported pain scores in patients undergoing a routine clinical procedure


Study hypothesis

The researchers intend to look at how the facial muscle activity readings measured during routine clinical care correlate with the participant's own reported real-time pain score during the procedure. They intend to use a visual analogue scale (VAS) pain score linked into a computer which will give a real-time self-reported pain score that they can then compare to the readings to that measured directly from the face. The VAS is a pain rating scale first used by Hayes and Patterson in 1921. It is the most widely used and validated scoring system in the subjective measurement of pain. It is based on self-reported measures of symptoms that are recorded with a single handwritten mark placed at one point along the length of a 10-cm line that represents a continuum between the two ends of the scale - “no pain” on the left end (0 cm) of the scale and the “worst pain” on the right end of the scale (10 cm). More recently digital methods using a sliding scale have superseded the paper version. These have been externally validated and are widely used in both experimental and clinical medicine.

Ethics approval

Approval pending, South Central - Oxford C - Research Ethics Committee (Level 3, Block B, Whitefriars Building, Lewins Mead, Bristol, BS1 2NT; Tel: +44 (0)207 104 8290, +44 (0)207 104 8041; Email:, ref: 19/SC/0274

Study design

Single-centre observational study

Primary study design


Secondary study design

Trial setting


Trial type


Patient information sheet

Not available in web format, please use contact details to request a participant information sheet.


Measuring pain felt by patients with a measurement of how their faces move


Patients receive a local anaesthetic injection before a planned hand operation. Whilst they are receiving the injection the facial muscle response is recorded non-invasively using specialized goggles containing muscle sensors. The data received from the facial muscle sensors will be correlated against the self-reported pain scores using a real-time visual analogue scale for a time period including baseline, during local anaesthetic injection and post injection. Measuring facial muscle activity using electromyography can be cumbersome due to the need for electrodes coated with conductive gel, adhesive pads and multiple trailing cables. Therefore we will use a new sensor system that simplifies the data collection by incorporating the sensors into a single system worn on the face like a pair of glasses. Pain expectation will also be considered, as well as participant anxiety traits and status prior to intervention.

Intervention type



Not Applicable

Drug names

Primary outcome measure

1. The timing and magnitude of the muscle response from the peri-orbital muscles to the painful stimulus (a local anaesthetic injection to the finger), recorded non-invasively using specialized goggles containing muscle sensors at baseline, during painful stimulus and post stimulus
2. Pain measured using a visual analogue scale (VAS) pain score linked into a computer at baseline, during painful stimulus and post stimulus

Secondary outcome measures

1. The amplitude of peri-orbital facial muscle activity (Corrugator Supercilii + Orbicularis Oculi), recorded non-invasively using specialized goggles containing muscle sensors at baseline, during painful stimulus and post stimulus
2. Heart rate and heart rate variability, measured using sensors in the specialised goggles and using a continuous ECG recording at baseline, during painful stimulus and post stimulus

Overall trial start date


Overall trial end date


Reason abandoned (if study stopped)


Participant inclusion criteria

1. Adult age 18+ with full capacity
2. ASA I (normal, healthy) and II (mild systemic disease; no functional limitation)
3. Fluent in English

1. Patients have received superficial trauma to the hand only
2. Patient is due to have examination and operation performed under local anaesthesia only
3. A digital ring block is planned for anaesthesia/analgesia during the procedure
4. No sedation/intravenous opioids are due to be administered
5. Oral analgesia via WHO analgesic ladder is permitted

Participant type


Age group




Target number of participants


Participant exclusion criteria

1. A history of chronic pain on long term opiates
2. A diagnosis of dementia/long-term memory impairment
3. Previous facial surgery (previous minor facial laceration suturing does not exclude)
4. Cosmetic facial procedures, e.g. botox injection or cosmetic “fillers”
5. Past history of facial neuromuscular disease eg Bell’s palsy
6. Pregnant

Recruitment start date


Recruitment end date



Countries of recruitment

United Kingdom

Trial participating centre

Queen Victoria Hospital
Holtye Road
East Grinstead
RH19 3DZ
United Kingdom

Sponsor information


Queen Victoria Hospital

Sponsor details

Holtye Road
East Grinstead
RH19 3DZ
United Kingdom
+44 (0)1342 414000

Sponsor type

Hospital/treatment centre



Funder type


Funder name

National Institute for Health Research

Alternative name(s)


Funding Body Type

government organisation

Funding Body Subtype

National government


United Kingdom

Results and Publications

Publication and dissemination plan

Planned publication in a high impact peer-reviewed journal – intend to publish Summer 2021.

IPD sharing statement
The datasets generated and/or analysed during the current study during this study will be included in the subsequent results publication.

Intention to publish date


Participant level data


Basic results (scientific)

Publication list

Publication citations

Additional files

Editorial Notes

27/06/2019: Trial's existence confirmed by ethics committee.