Trigeminal NeuralgiaTNBRNCT05328661
Pathophysiological Mechanisms of Trigeminal Neuralgia - Neurophysiological Assessment of the Blink-reflex
An observational study of Trigeminal Neuralgia, run by Danish Headache Center at 1 site in Denmark.
Trial summary
This study aims to increase the understanding of the pathophysiology of trigeminal neuralgia by investigating the potential association between blink reflex abnormalities and phenotypical traits e.g. clinical characteristics and neuroimaging findings. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Trigeminal Neuralgia
- What is being tested?
- Blink reflex
- How many people
- 60 participants
- Where
- 1 siteDenmark
- Study dates
- 1 May 2021to 1 Dec 2022
- Phase
- Observational
- 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 years and older
- All sexes
- Adult, Older adult
Study population: Trigemnal neuralgia patients either with classic or idopathic TN
Who may be able to join
- Subjects of both sexes with trigeminal neuralgia must meet the following inclusion criteria to be eligible for participation:
- Age 18 years or older
- Must be able to give Signed Informed Consent prior to study entry. Appendix X
- Must fulfill the ICHD-3 diagnostic criteria1 for classical, idiopathic or secondary TN.
- Has had a 3.0 Tesla MRI according to the trigeminal neuralgia protocol, maximum 2 years before or after the assessment of the blink-reflex.
- Has had a semi-structured interview and neurological examination by the independent assessors, maximum 2 years before or after the assessment of the blink-reflex.
Who cannot join
- Subjects will be excluded if one of the following exclusion criteria is met:
- If the patient is not able to give informed consent due to mental challenges
- Previous neurosurgical treatment (microvascular decompression and/or ablative procedures) for trigeminal neuralgia
- Bilateral trigeminal neuralgia
- Symptomatic trigeminal neuralgia
- Findings of sensory abnormalities detected at clinical neurological examination
Trial locations and contacts
1 site in 1 country.
About this study
This study aims to increase the understanding of the pathophysiology of trigeminal neuralgia by investigating the potential association between blink reflex abnormalities and phenotypical traits e.g. clinical characteristics and neuroimaging findings.
Read the detailed description
We hypothesize:
Patients with classical trigeminal neuralgia have a prolonged latency and reduced amplitudes of the blink-reflex on the pain side compared to patients with idiopathic TN
The latency and amplitudes of the blink-reflex is normal in patients with idiopathic trigeminal neuralgia
Patients with concomitant persistent pain have a prolonged latency and reduced amplitudes of the blink reflex on the pain side compared to patients with pure paroxysmal TN
More men than women have a prolonged latency and reduced amplitudes of the blink reflex
Patients with neurovascular contact with morphological changes have prolonged latency and reduced amplitudes of the blink reflex compared to patients with simple neurovascular contact
Patients with secondary TN have prolonged latency and reduced amplitudes of the blink reflex compared to patients with simple neurovascular contact
Patients with neurovascular contact with morphological changes have prolonged latency and reduced amplitudes of the blink reflex on the pain side compared to the non-pain side
Study population
All patients with the diagnosis of primary or secondary trigeminal neuralgia, seen in the outpatient clinic at the Danish Headache Center will be screened for eligibility to participate the study. Clinical routine is not influenced by participation in this observational study. Patients will be offered the same treatment as patients not participating.
Setting
All patients with classic, idiopathic and symptomatic TN who have an appointment with a physician at the outpatient clinic at the Danish Headache Center as part of their work-up will, when they arrive at the center for their appointment, be asked if they want to participate in the study. The patients will be asked consecutively and there will be no prior recruitment of the patients. See recruitment below section 6.1. The study will not influence decisions regarding treatment of TN for the patients included in this protocol. Patients will be treated at the discretion of their own physician and the assessments listed below, are an integrated part of the clinical work-up and follow-up.
Assessments
Standardised data obtained from the medical chart
The following data will be obtained and registered from the medical chart of each patient that is included in the study:
Gender, date of birth, family history of TN or other facial pain
Duration and localization of TN, use of and response to previous medical treatments
Severity of pain at the time of examination - using Verbal Numerical Rating Scale (VNRS)
Location and trigger factors for TN
Previous neurosurgical treatment for TN
Additional concomitant diseases and medication
Type and dosage of TN related medication, if any
The result of the neurological exam.
Short interview on the examination day
On the day of the blink reflex examination, each patient will be asked by a trained biomedical laboratory scientist, nurse or medical student about the following:
Then the number of paroxysms
The current level of pain (VNRS)
The current dosage of TN medicine, will be on the day of neurophysiological assessments.
The trained personnel will not ask about the side of pain and will not know the result of the MRI evaluation, so they are blinded in terms of side of pain and what type of TN patient they investigate.
Neuroradiological assessment
The 3.0 Tesla MRI, performed according to a special TN protocol will be evaluated by a neuroradiologist, blinded for pain side. The neuro imaging data will be taken from the patient electronic journal. The following data will be registered:
Degree (no contact, simple contact, displacement/compression or atrophy of the nerve), location and type (arterial, venous or mixed) of NVC
Neurophysiological assessment (blink-reflex)
Electromyographic Recording:
We want to record signals from both eyes (see image). Channel 1: left eye. Channel 2: right eye
After connecting the cables to Channels 1 and 2 we can connect the electrodes to the black and red terminal wires: Black cable à active electrode: placed on the midline of the lower eyelid (orbicularis oculi muscles). Red cable à reference electrode: lateral to the eye (where the bone is superficial) We need one Green cable àground electrode: forehead or shoulder.
- Conditions
- Trigeminal Neuralgia
- Being tested
- Blink reflex
- Medical subject headings
- Trigeminal Neuralgia
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Blink reflexDiagnostic test
The stimulator is directly connected to the right side of the frontal board. The sponge must be soaked in water or saline before being inserted into the stimulator. Dry them a bit to avoid leaking on the stimulator (it could create a bridge between the two poles). We want to stimulate the supraorbital nerve at its emergence from the eyebrow arch (the supraorbital foramen in the supra-orbital margin bone is easy to palpate 1 cm laterally to the root of the nose). We place the stimulator above the emergence of the supraorbital nerve, with the distal pole placed below. The final intensity of stimulation is generally between 5 to 10 mA, but higher intensities sometime are required.
What is being measured
The primary outcome is the main question the study is designed to answer.
Latency and amplitude of blink reflex on the pain side of classical trigeminal neuralgia patients.
We place the stimulator above the emergence of the supraorbital nerve, with the distal pole placed below. The subject could be in a sitting or supine position. He keeps his eyes opened and relaxed. The final intensity of stimulation is generally between 5to 10mA, but higher intensities sometime are required. We don't start from this intensity, but we increase it gradually from 2mA, in steps of 1-2mA. The time between consecutive stimuli must not be under 45 seconds, in order to avoid habituation. Before the stimuli is delivered, we look at the real-time activity box to be sure that the subject is relaxed. We aim to record at least 2-3 consecutive sweeps with a stable latency of the R1 and R2 components.
Measured: 1 year
Secondary outcomes (1)
Latency and amplitude of blink reflex on the pain side of idiopathic trigeminal neuralgia patients
We place the stimulator above the emergence of the supraorbital nerve, with the distal pole placed below. The subject could be in a sitting or supine position. He keeps his eyes opened and relaxed. The final intensity of stimulation is generally between 5to 10mA, but higher intensities sometime are required. We don't start from this intensity, but we increase it gradually from 2mA, in steps of 1-2mA. The time between consecutive stimuli must not be under 45 seconds, in order to avoid habituation. Before the stimuli is delivered, we look at the real-time activity box to be sure that the subject is relaxed. We aim to record at least 2-3 consecutive sweeps with a stable latency of the R1 and R2 components.
Measured: 1 year
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted14 Apr 2022
- Study start1 May 2021
- Primary completion1 Sep 2022
- Study completion1 Dec 2022
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Trigeminal NeuralgiaStudies 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
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 60 participants (actual)
Sponsor and investigators
- Lead sponsor
- Danish Headache Center
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Henrik Schytz, Danish Headache Center
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05328661
- Sponsor's protocol ID
- DanishHC180322Blink
- Acronym
- TNBR
- Status last verified
- Jan 2025
- First submitted
- 18 Mar 2022
- Last updated
- 30 Jan 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
Bjerring B, Maarbjerg S, Heinskou T, Bendtsen L, Nikolic M, Grillo V, Icco R, Schytz HW. Comparison of the blink reflex in classical and idiopathic trigeminal neuralgia. Cephalalgia. 2023 Jul;43(7):3331024231191136. doi: 10.1177/03331024231191136.
PubMed 37525973
Study at a glance
From the registry record, last updated by the sponsor on 30 Jan 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Pathophysiological Mechanisms of Trigeminal Neuralgia - Neurophysiological Assessment of the Blink-reflex
- ClinicalTrials.gov ID
- NCT05328661
- Acronym / sponsor ID
- TNBR / DanishHC180322Blink
- Conditions
- Trigeminal Neuralgia
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 60 participants (actual)
- Lead sponsor
- Danish Headache CenterUniversity, hospital or other
- Study start
- 1 May 2021 (actual)
- Primary completion
- 1 Sep 2022 (actual)
- Study completion
- 1 Dec 2022 (actual)
- First posted
- 14 Apr 2022 (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.
This study aims to increase the understanding of the pathophysiology of trigeminal neuralgia by investigating the potential association between blink reflex abnormalities and phenotypical traits e.g. clinical characteristics and neuroimaging findings.
Detailed description
We hypothesize:
Patients with classical trigeminal neuralgia have a prolonged latency and reduced amplitudes of the blink-reflex on the pain side compared to patients with idiopathic TN
The latency and amplitudes of the blink-reflex is normal in patients with idiopathic trigeminal neuralgia
Patients with concomitant persistent pain have a prolonged latency and reduced amplitudes of the blink reflex on the pain side compared to patients with pure paroxysmal TN
More men than women have a prolonged latency and reduced amplitudes of the blink reflex
Patients with neurovascular contact with morphological changes have prolonged latency and reduced amplitudes of the blink reflex compared to patients with simple neurovascular contact
Patients with secondary TN have prolonged latency and reduced amplitudes of the blink reflex compared to patients with simple neurovascular contact
Patients with neurovascular contact with morphological changes have prolonged latency and reduced amplitudes of the blink reflex on the pain side compared to the non-pain side
Study population
All patients with the diagnosis of primary or secondary trigeminal neuralgia, seen in the outpatient clinic at the Danish Headache Center will be screened for eligibility to participate the study. Clinical routine is not influenced by participation in this observational study. Patients will be offered the same treatment as patients not participating.
Setting
All patients with classic, idiopathic and symptomatic TN who have an appointment with a physician at the outpatient clinic at the Danish Headache Center as part of their work-up will, when they arrive at the center for their appointment, be asked if they want to participate in the study. The patients will be asked consecutively and there will be no prior recruitment of the patients. See recruitment below section 6.1. The study will not influence decisions regarding treatment of TN for the patients included in this protocol. Patients will be treated at the discretion of their own physician and the assessments listed below, are an integrated part of the clinical work-up and follow-up.
Assessments
Standardised data obtained from the medical chart
The following data will be obtained and registered from the medical chart of each patient that is included in the study:
Gender, date of birth, family history of TN or other facial pain
Duration and localization of TN, use of and response to previous medical treatments
Severity of pain at the time of examination - using Verbal Numerical Rating Scale (VNRS)
Location and trigger factors for TN
Previous neurosurgical treatment for TN
Additional concomitant diseases and medication
Type and dosage of TN related medication, if any
The result of the neurological exam.
Short interview on the examination day
On the day of the blink reflex examination, each patient will be asked by a trained biomedical laboratory scientist, nurse or medical student about the following:
Then the number of paroxysms
The current level of pain (VNRS)
The current dosage of TN medicine, will be on the day of neurophysiological assessments.
The trained personnel will not ask about the side of pain and will not know the result of the MRI evaluation, so they are blinded in terms of side of pain and what type of TN patient they investigate.
Neuroradiological assessment
The 3.0 Tesla MRI, performed according to a special TN protocol will be evaluated by a neuroradiologist, blinded for pain side. The neuro imaging data will be taken from the patient electronic journal. The following data will be registered:
Degree (no contact, simple contact, displacement/compression or atrophy of the nerve), location and type (arterial, venous or mixed) of NVC
Neurophysiological assessment (blink-reflex)
Electromyographic Recording:
We want to record signals from both eyes (see image). Channel 1: left eye. Channel 2: right eye
After connecting the cables to Channels 1 and 2 we can connect the electrodes to the black and red terminal wires: Black cable à active electrode: placed on the midline of the lower eyelid (orbicularis oculi muscles). Red cable à reference electrode: lateral to the eye (where the bone is superficial) We need one Green cable àground electrode: forehead or shoulder.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Age groups
- Adult, Older adult
- Study population
- Trigemnal neuralgia patients either with classic or idopathic TN
Key inclusion criteria (6 listed)
- Subjects of both sexes with trigeminal neuralgia must meet the following inclusion criteria to be eligible for participation:
- Age 18 years or older
- Must be able to give Signed Informed Consent prior to study entry. Appendix X
- Must fulfill the ICHD-3 diagnostic criteria1 for classical, idiopathic or secondary TN.
- Has had a 3.0 Tesla MRI according to the trigeminal neuralgia protocol, maximum 2 years before or after the assessment of the blink-reflex.
Key exclusion criteria (6 listed)
- Subjects will be excluded if one of the following exclusion criteria is met:
- If the patient is not able to give informed consent due to mental challenges
- Previous neurosurgical treatment (microvascular decompression and/or ablative procedures) for trigeminal neuralgia
- Bilateral trigeminal neuralgia
- Symptomatic trigeminal neuralgia
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 |
|---|---|---|
| Blink reflexThe stimulator is directly connected to the right side of the frontal board. The sponge must be soaked in water or saline before being inserted into the stimulator. Dry them a bit to avoid leaking on the stimulator (it could create a bridge between the two poles). We want to stimulate the supraorbital nerve at its emergence from the eyebrow arch (the supraorbital foramen in the supra-orbital margin bone is easy to palpate 1 cm laterally to the root of the nose). We place the stimulator above the emergence of the supraorbital nerve, with the distal pole placed below. The final intensity of stimulation is generally between 5 to 10 mA, but higher intensities sometime are required. | Diagnostic test | – |
Primary outcome
Latency and amplitude of blink reflex on the pain side of classical trigeminal neuralgia patients.
Time frame: 1 year
We place the stimulator above the emergence of the supraorbital nerve, with the distal pole placed below. The subject could be in a sitting or supine position. He keeps his eyes opened and relaxed. The final intensity of stimulation is generally between 5to 10mA, but higher intensities sometime are required. We don't start from this intensity, but we increase it gradually from 2mA, in steps of 1-2mA. The time between consecutive stimuli must not be under 45 seconds, in order to avoid habituation. Before the stimuli is delivered, we look at the real-time activity box to be sure that the subject is relaxed. We aim to record at least 2-3 consecutive sweeps with a stable latency of the R1 and R2 components.
1 secondary outcome
Latency and amplitude of blink reflex on the pain side of idiopathic trigeminal neuralgia patients
Time frame: 1 year
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 30 Jan 2025.
- Derived from this study: PubMed 37525973Bjerring B, Maarbjerg S, Heinskou T, Bendtsen L, Nikolic M, Grillo V, Icco R, Schytz HW. Comparison of the blink reflex in classical and idiopathic trigeminal neuralgia. Cephalalgia. 2023 Jul;43(7):3331024231191136. doi: 10.1177/03331024231191136.
- Individual participant dataSharing planned: No
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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?
An observational study of Trigeminal Neuralgia, run by Danish Headache Center at 1 site in Denmark.
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 6 inclusion and 6 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 30 Jan 2025. 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 Denmark. 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?
Latency and amplitude of blink reflex on the pain side of classical trigeminal neuralgia patients. (time frame: 1 year). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT05328661, which also lists 1 linked publication.
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 30 Jan 2025.