Healthy Adult ParticipantsNCT07635979
Physiological Responses to Upper Limb NMES
A study testing Firefly NMES device in people with Healthy Adult Participants, run by Kieron.Day at 1 site in United Kingdom.
Trial summary
The primary objective of this study is to explore the application of the Firefly® device for delivering NMES to anatomically defined regions of the upper limb and to observe associated physiological changes. Read more about this study
- Who is it for?
- Ages 18 to 45 years
- Conditions the study is for
- Healthy Adult Participants
- What is being tested?
- Firefly NMES device
- Type of treatment
- Medical device
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 10 participants
- Where
- 1 siteUnited Kingdom
- Study dates
- 19 Sep 2025to 3 Oct 2025
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 45 years
- All sexes
- No healthy volunteers
- Adult
Who may be able to join
- Aged 18 to 45 years (inclusive)
- No known history of vascular or neurological conditions affecting the upper extremities
- Able to read, understand, and communicate in English to ensure informed consent and safe participation in the study
Who cannot join
- Presence of any condition that contraindicates the use of neuromuscular electrical stimulation (e.g., implanted pacemaker, epilepsy)
- Current or recent injury to the upper limbs that may interfere with stimulation or measurement
- Anatomical variations in the brachial artery or axillary vein, specifically vascular branching outside expected anatomical locations, as identified by ultrasound, which may impair accurate blood flow measurement or device placement
- Currently participating in another interventional or physiological research study or having done so within the past 30 days.
- Currently pregnant
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Exploring Local Physiological Changes in the Arm During NMES Using the Firefly® Device
The primary objective of this study is to explore the application of the Firefly® device for delivering NMES to anatomically defined regions of the upper limb and to observe associated physiological changes. Specifically, the study will assess alterations in arterial and venous blood flow, as well as local muscle oxygen saturation, as potential indicators of muscle perfusion during NMES.
Read the detailed description
Participants will undergo NMES using the Firefly® device, applied to two predefined regions of the upper limb: one targeting the anterior arm nerve bundle (a collective term referring to motor and sensory nerves within the anterior and medial compartments of the upper arm, including the musculocutaneous and adjacent (median, medial cutaneous, ulnar and radial) nerves, and the other targeting the median nerve in the proximal forearm.
Vascular responses will be assessed at two sites, the brachial artery and axillary vein, using Doppler ultrasound. For each nerve-vascular site pairing, NMES will alternate between stimulation OFF and ON conditions (10 OFF and 10 ON cycles), comprising one stimulation block of approximately 20 minutes. Each participant will complete four stimulation blocks in total.
During both ON and OFF phases, blood flow volume and haemodynamic parameters, including peak systolic velocity (PSV), end-diastolic velocity (EDV), and resistive index (RI), will be recorded. Additionally, local muscle oxygen saturation (SmO₂) will be continuously monitored using functional near-infrared spectroscopy (fNIRS) to assess tissue-level physiological changes.
The total study participation time per individual is approximately 2 hours.
- Conditions
- Healthy Adult Participants
- Being tested
- Firefly NMES device
- Keywords
- Blood Circulation, Neuromuscular Electrical Stimulation, Muscle Contraction, Hemodynamics
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Firefly NMES deviceDevice
Firefly NMES device applied to the upper limb during a single-visit exploratory pysiological study
| Study group | Role | What they receive |
|---|---|---|
| Single experimental arm: Firefly NMES | Experimental | Not described Receives: Device: Firefly NMES device |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in upper-limb blood flow volume during NMES (ON vs OFF)
Within-subject change in upper-limb blood flow volume (mL/min) measured using Doppler ultrasound during neuromuscular electrical stimulation (NMES) delivered via the Firefly device, comparing stimulation ON versus OFF conditions. Measurements will be collected across repeated stimulation cycles at predefined upper-limb stimulation zones and vascular assessment sites.
Measured: During single study visit (approximately 2 hours), across repeated stimulation ON/OFF cycles
Change in upper-limb peak systolic velocity during NMES (ON vs OFF)
Within-subject change in upper-limb peak systolic velocity (PSV; cm/s) measured using Doppler ultrasound during NMES delivered via the Firefly device, comparing stimulation ON versus OFF conditions across repeated stimulation cycles at predefined upper-limb stimulation zones and vascular assessment sites.
Measured: During a single study visit (approximately 2 hours), across repeated stimulation ON/OFF cycles.
Change in upper-limb end-diastolic velocity during NMES (ON vs OFF)
Within-subject change in upper-limb end-diastolic velocity (EDV; cm/s) measured using Doppler ultrasound during NMES delivered via the Firefly device, comparing stimulation ON versus OFF conditions across repeated stimulation cycles at predefined upper-limb stimulation zones and vascular assessment sites.
Measured: During a single study visit (approximately 2 hours), across repeated stimulation ON/OFF cycles.
Change in upper-limb resistive index during NMES (ON vs OFF)
Within-subject change in upper-limb resistive index (RI; unitless ratio) derived from Doppler ultrasound measurements during NMES delivered via the Firefly device, comparing stimulation ON versus OFF conditions across repeated stimulation cycles at predefined upper-limb stimulation zones and vascular assessment sites.
Measured: During a single study visit (approximately 2 hours), across repeated stimulation ON/OFF cycles.
Change in upper-limb muscle oxygen saturation during NMES (ON vs OFF)
Within-subject change in upper-limb muscle oxygen saturation (SmO₂; %) measured continuously using functional near-infrared spectroscopy (fNIRS) during NMES delivered via the Firefly device, comparing stimulation ON versus OFF conditions across repeated stimulation cycles at predefined upper-limb stimulation zones and assessment sites.
Measured: During a single study visit (approximately 2 hours), across repeated stimulation ON/OFF cycles.
Secondary outcomes (1)
Incidence of adverse events and device-related effects
Number and type of adverse events (AEs), serious adverse events (SAEs), adverse device effects (ADEs), serious adverse device effects (SADEs), and device deficiencies observed during study participation.
Measured: During single study visit (approximately 2 hours)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted9 Jun 2026
- Study start19 Sep 2025
- Primary completion3 Oct 2025
- Study completion3 Oct 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Healthy Adult ParticipantsStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Not applicable
- Intervention model
- Single group
- Model description
- This is a single-centre, within-subject exploratory study designed to evaluate the physiological effects of NMES applied to the upper limb using the Firefly® device. A repeated-measures design will be used to compare physiological parameters under alternating stimulation OFF and ON conditions.
- Masking
- None (open label)
- Enrolment
- 10 participants (actual)
Sponsor and investigators
- Lead sponsor
- Kieron.Day
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor-investigator, Kieron.Day, Firstkind Ltd
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07635979
- Sponsor's protocol ID
- FFR-ARM-002
- Other IDs
- FFR-ARM-002
- Status last verified
- Jun 2026
- First submitted
- 10 Apr 2026
- Last updated
- 9 Jun 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: Available upon request
Study at a glance
From the registry record, last updated by the sponsor on 9 Jun 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Exploring Local Physiological Changes in the Arm During NMES Using the Firefly® Device
- ClinicalTrials.gov ID
- NCT07635979
- Acronym / sponsor ID
- FFR-ARM-002
- Conditions
- Healthy Adult Participants
- Keywords
- Blood Circulation, Neuromuscular Electrical Stimulation, Muscle Contraction, Hemodynamics
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 10 participants (actual)
- Lead sponsor
- Kieron.DayIndustry (pharma, biotech, devices)
- Study start
- 19 Sep 2025 (actual)
- Primary completion
- 3 Oct 2025 (actual)
- Study completion
- 3 Oct 2025 (actual)
- First posted
- 9 Jun 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The primary objective of this study is to explore the application of the Firefly® device for delivering NMES to anatomically defined regions of the upper limb and to observe associated physiological changes. Specifically, the study will assess alterations in arterial and venous blood flow, as well as local muscle oxygen saturation, as potential indicators of muscle perfusion during NMES.
Detailed description
Participants will undergo NMES using the Firefly® device, applied to two predefined regions of the upper limb: one targeting the anterior arm nerve bundle (a collective term referring to motor and sensory nerves within the anterior and medial compartments of the upper arm, including the musculocutaneous and adjacent (median, medial cutaneous, ulnar and radial) nerves, and the other targeting the median nerve in the proximal forearm.
Vascular responses will be assessed at two sites, the brachial artery and axillary vein, using Doppler ultrasound. For each nerve-vascular site pairing, NMES will alternate between stimulation OFF and ON conditions (10 OFF and 10 ON cycles), comprising one stimulation block of approximately 20 minutes. Each participant will complete four stimulation blocks in total.
During both ON and OFF phases, blood flow volume and haemodynamic parameters, including peak systolic velocity (PSV), end-diastolic velocity (EDV), and resistive index (RI), will be recorded. Additionally, local muscle oxygen saturation (SmO₂) will be continuously monitored using functional near-infrared spectroscopy (fNIRS) to assess tissue-level physiological changes.
The total study participation time per individual is approximately 2 hours.
Study design
- Primary purpose
- Basic science
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
- Model description
- This is a single-centre, within-subject exploratory study designed to evaluate the physiological effects of NMES applied to the upper limb using the Firefly® device. A repeated-measures design will be used to compare physiological parameters under alternating stimulation OFF and ON conditions.
| Arm | Type | Receives |
|---|---|---|
| Single experimental arm: Firefly NMES | Experimental | Device: Firefly NMES device |
Who may qualify
- Ages
- 18 to 45 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult
Key inclusion criteria (3 listed)
- Aged 18 to 45 years (inclusive)
- No known history of vascular or neurological conditions affecting the upper extremities
- Able to read, understand, and communicate in English to ensure informed consent and safe participation in the study
Key exclusion criteria (5 listed)
- Presence of any condition that contraindicates the use of neuromuscular electrical stimulation (e.g., implanted pacemaker, epilepsy)
- Current or recent injury to the upper limbs that may interfere with stimulation or measurement
- Anatomical variations in the brachial artery or axillary vein, specifically vascular branching outside expected anatomical locations, as identified by ultrasound, which may impair accurate blood flow measurement or device placement
- Currently participating in another interventional or physiological research study or having done so within the past 30 days.
- Currently pregnant
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Firefly NMES deviceFirefly NMES device applied to the upper limb during a single-visit exploratory pysiological study | Device | Single experimental arm: Firefly NMES |
Primary outcome
Change in upper-limb blood flow volume during NMES (ON vs OFF)
Time frame: During single study visit (approximately 2 hours), across repeated stimulation ON/OFF cycles
Within-subject change in upper-limb blood flow volume (mL/min) measured using Doppler ultrasound during neuromuscular electrical stimulation (NMES) delivered via the Firefly device, comparing stimulation ON versus OFF conditions. Measurements will be collected across repeated stimulation cycles at predefined upper-limb stimulation zones and vascular assessment sites.
Change in upper-limb peak systolic velocity during NMES (ON vs OFF)
Time frame: During a single study visit (approximately 2 hours), across repeated stimulation ON/OFF cycles.
Within-subject change in upper-limb peak systolic velocity (PSV; cm/s) measured using Doppler ultrasound during NMES delivered via the Firefly device, comparing stimulation ON versus OFF conditions across repeated stimulation cycles at predefined upper-limb stimulation zones and vascular assessment sites.
Change in upper-limb end-diastolic velocity during NMES (ON vs OFF)
Time frame: During a single study visit (approximately 2 hours), across repeated stimulation ON/OFF cycles.
Within-subject change in upper-limb end-diastolic velocity (EDV; cm/s) measured using Doppler ultrasound during NMES delivered via the Firefly device, comparing stimulation ON versus OFF conditions across repeated stimulation cycles at predefined upper-limb stimulation zones and vascular assessment sites.
Change in upper-limb resistive index during NMES (ON vs OFF)
Time frame: During a single study visit (approximately 2 hours), across repeated stimulation ON/OFF cycles.
Within-subject change in upper-limb resistive index (RI; unitless ratio) derived from Doppler ultrasound measurements during NMES delivered via the Firefly device, comparing stimulation ON versus OFF conditions across repeated stimulation cycles at predefined upper-limb stimulation zones and vascular assessment sites.
Change in upper-limb muscle oxygen saturation during NMES (ON vs OFF)
Time frame: During a single study visit (approximately 2 hours), across repeated stimulation ON/OFF cycles.
Within-subject change in upper-limb muscle oxygen saturation (SmO₂; %) measured continuously using functional near-infrared spectroscopy (fNIRS) during NMES delivered via the Firefly device, comparing stimulation ON versus OFF conditions across repeated stimulation cycles at predefined upper-limb stimulation zones and assessment sites.
1 secondary outcome
Incidence of adverse events and device-related effects
Time frame: During single study visit (approximately 2 hours)
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 9 Jun 2026.
- Individual participant dataSharing planned: Yes. Available upon request
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Firefly NMES device in people with Healthy Adult Participants, run by Kieron.Day at 1 site in United Kingdom.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 5 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 9 Jun 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United Kingdom. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in upper-limb blood flow volume during NMES (ON vs OFF) (time frame: During single study visit (approximately 2 hours), across repeated stimulation ON/OFF cycles). The study lists 5 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 9 Jun 2026.