Loss of Depotentiation in Focal Dystonia
| Status: | Recruiting |
|---|---|
| Conditions: | Healthy Studies, Neurology, Orthopedic |
| Therapuetic Areas: | Neurology, Orthopedics / Podiatry, Other |
| Healthy: | No |
| Age Range: | 18 - Any |
| Updated: | 3/27/2019 |
| Start Date: | September 20, 2017 |
| End Date: | December 31, 2021 |
| Contact: | Elaine P Considine, R.N. |
| Email: | considinee@ninds.nih.gov |
| Phone: | (301) 435-8518 |
Background
Focal dystonia is a brain disorder. It affects a muscle or muscles in a specific part of the
body. Researchers think it may be related to excessive training or practice. They want to
know more about how much training might trigger focal dystonia.
Objectives:
To study why people develop focal dystonia. To study how brain plasticity changes with focal
dystonia.
Eligibility:
People at least 18 years of age with focal dystonia.
Healthy volunteers the same age are also needed.
Design:
Participants will be screened with a physical exam and questions. They may have blood and
urine tests.
Participants will have up to 3 testing visits.
Participants will have small electrodes stuck on the skin on the hands or arms. Muscle
activity will be recorded.
Participants will have transcranial magnetic stimulation (TMS). A wire coil will be placed
onto the scalp. A brief electrical current will pass through the coil. The current will
create a magnetic field that affects brain activity.
Participants may be asked to tense certain muscles or do simple actions during TMS.
A nerve at the wrist will get weak electrical stimulation. The stimulation may be paired with
TMS for very short times.
Participants will receive repeated magnetic pulses. Participants will receive a total of 150
pulses during a 10-second period. An entire testing visit will last about 3 hours.
Focal dystonia is a brain disorder. It affects a muscle or muscles in a specific part of the
body. Researchers think it may be related to excessive training or practice. They want to
know more about how much training might trigger focal dystonia.
Objectives:
To study why people develop focal dystonia. To study how brain plasticity changes with focal
dystonia.
Eligibility:
People at least 18 years of age with focal dystonia.
Healthy volunteers the same age are also needed.
Design:
Participants will be screened with a physical exam and questions. They may have blood and
urine tests.
Participants will have up to 3 testing visits.
Participants will have small electrodes stuck on the skin on the hands or arms. Muscle
activity will be recorded.
Participants will have transcranial magnetic stimulation (TMS). A wire coil will be placed
onto the scalp. A brief electrical current will pass through the coil. The current will
create a magnetic field that affects brain activity.
Participants may be asked to tense certain muscles or do simple actions during TMS.
A nerve at the wrist will get weak electrical stimulation. The stimulation may be paired with
TMS for very short times.
Participants will receive repeated magnetic pulses. Participants will receive a total of 150
pulses during a 10-second period. An entire testing visit will last about 3 hours.
Objectives
Simulation paradigms can induce plastic changes in brain excitability. Paired associative
stimulation (PAS) with an interstimulus interval of 25 ms (PAS25) induces a long-term
potentiation (LTP)-like effect while that at an interval of 10 ms (PAS10) induces a long-term
depression (LTD)-like effect. The LTP-like effect induced by PAS25 is exaggerated in patients
with focal dystonia. The LTD-like effect with PAS10 is also increased in focal dystonia but
not in the target area of PAS. Depotentiation refers to the reversal of LTP by which LTP is
abolished by a following procedure that has no effect when it is given alone. Brain-derived
neurotrophic factor has a variety of roles in modulating both LTP and LTD. The Val66Met
single nucleotide polymorphism is related to abnormal cortical plasticity. In this protocol,
we propose a study to test the hypothesis that depotentiation is weaker in focal dystonia
patients compared to healthy controls. In addition, motor cortical inhibition is decreased in
focal dystonia. We will test the changes in motor cortical inhibition following different
interventional procedures in focal dystonia. We will also test the relationship between
depotentiation and LTP/LTD-like effects in focal dystonia patients.
Study population
We intend to study up to 20 patients with focal dystonia and 20 age-matched healthy
volunteers. Subjects will complete up to 3 study visits involving 3 different interventional
procedures. Various outcome measures will be performed during each study visit.
Design
This is a hypothesis-driven study. We will compare the depotentiation effect in patients with
focal dystonia to that in healthy volunteers. Patients will be evaluated with a clinical
rating scale during the screening visit. Three interventional procedures will be tested
during three study visits. Specifically, PAS25-cTBS150 tests the primary hypothesis with a
depotentiation effect. PAS25 tests LTP-like effect and PAS10 tests the LTD-like effect. We
will investigate the difference in outcome measures between patients and healthy volunteers
after the interventional procedures. We will perform genetic tests to identify the
brain-derived neurotrophic factor genotype in the patients and healthy volunteers.
Outcome measures
The primary outcome measure is motor-evoked potential (MEP) induced by transcranial magnetic
stimulation immediately after the interventional procedure of PAS25-cTBS150. We will compare
MEP amplitude in patients with that in healthy volunteers to identify whether depotentiation
is weaker in focal dystonia. The secondary outcome measures are MEP amplitudes at other time
points after the PAS25-cTBS150 procedure. We will also perform exploratory studies to
investigate the effects of interventional procedures of PAS25 and PAS10 alone. We will test
the relationship between depotentiation and LTP/LTD-like effects in focal dystonia. We will
also study other exploratory outcome measures such as: resting and active motor threshold,
MEP recruitment curve, excitability of motor cortical circuits (short- and long-interval
intracortical inhibition, and intracortical facilitation) after three different
interventional procedures.
Simulation paradigms can induce plastic changes in brain excitability. Paired associative
stimulation (PAS) with an interstimulus interval of 25 ms (PAS25) induces a long-term
potentiation (LTP)-like effect while that at an interval of 10 ms (PAS10) induces a long-term
depression (LTD)-like effect. The LTP-like effect induced by PAS25 is exaggerated in patients
with focal dystonia. The LTD-like effect with PAS10 is also increased in focal dystonia but
not in the target area of PAS. Depotentiation refers to the reversal of LTP by which LTP is
abolished by a following procedure that has no effect when it is given alone. Brain-derived
neurotrophic factor has a variety of roles in modulating both LTP and LTD. The Val66Met
single nucleotide polymorphism is related to abnormal cortical plasticity. In this protocol,
we propose a study to test the hypothesis that depotentiation is weaker in focal dystonia
patients compared to healthy controls. In addition, motor cortical inhibition is decreased in
focal dystonia. We will test the changes in motor cortical inhibition following different
interventional procedures in focal dystonia. We will also test the relationship between
depotentiation and LTP/LTD-like effects in focal dystonia patients.
Study population
We intend to study up to 20 patients with focal dystonia and 20 age-matched healthy
volunteers. Subjects will complete up to 3 study visits involving 3 different interventional
procedures. Various outcome measures will be performed during each study visit.
Design
This is a hypothesis-driven study. We will compare the depotentiation effect in patients with
focal dystonia to that in healthy volunteers. Patients will be evaluated with a clinical
rating scale during the screening visit. Three interventional procedures will be tested
during three study visits. Specifically, PAS25-cTBS150 tests the primary hypothesis with a
depotentiation effect. PAS25 tests LTP-like effect and PAS10 tests the LTD-like effect. We
will investigate the difference in outcome measures between patients and healthy volunteers
after the interventional procedures. We will perform genetic tests to identify the
brain-derived neurotrophic factor genotype in the patients and healthy volunteers.
Outcome measures
The primary outcome measure is motor-evoked potential (MEP) induced by transcranial magnetic
stimulation immediately after the interventional procedure of PAS25-cTBS150. We will compare
MEP amplitude in patients with that in healthy volunteers to identify whether depotentiation
is weaker in focal dystonia. The secondary outcome measures are MEP amplitudes at other time
points after the PAS25-cTBS150 procedure. We will also perform exploratory studies to
investigate the effects of interventional procedures of PAS25 and PAS10 alone. We will test
the relationship between depotentiation and LTP/LTD-like effects in focal dystonia. We will
also study other exploratory outcome measures such as: resting and active motor threshold,
MEP recruitment curve, excitability of motor cortical circuits (short- and long-interval
intracortical inhibition, and intracortical facilitation) after three different
interventional procedures.
- INCLUSION CRITERIA:
Inclusion criteria for healthy controls:
- At least 18 years old.*
- Able to give informed consent.
- Able to comply with all study procedures.
- Abstain from alcohol for at least 48 hours prior to each study visit and caffeine on
the day of the visit.
- Have no neurological or psychiatric disorders established by history and
physical/neurological examination.
- = A maximum of 10 subjects who are over the age of 70 will be screened for
plasticity. If none of these subjects have plasticity, we will not accrue any
more subjects over the age of 70.
Inclusion criteria for focal dystonia patients:
- At least 18-years old.*
- Able to give informed consent.
- Able to comply with all study procedures.
- Abstain from alcohol for at least 48 hours prior to each visit of the study and
caffeine on the day of the visit.
- Have an established diagnosis of focal dystonia.
- No botulinum toxin injections at least in the past 3 months.
- = A maximum of 10 subjects who are over the age of 70 will be screened for
plasticity. If none of these subjects have plasticity, we will not accrue any
more subjects over the age of 70.
EXCLUSION CRITERIA:
- Self-reported consumption of > 14 alcoholic drinks/week for a man and > 7 alcoholic
drinks/week for a woman.
- Focal dystonia patients: presence of abnormal findings on neurological examination
except for the diagnosis of focal dystonia. Healthy volunteers: no abnormal findings
on neurological examination.
- History of or current brain tumor, stroke, head trauma with loss of consciousness,
epilepsy or seizures.
- Have a Baclofen pump, or have neurostimulators for pain.
- Pregnant or breastfeeding women.
- Current episode of major depression or any major psychiatric illness.
- Taking medications that act directly on the central nervous system such as
anti-epileptics, anti-histamines, anti-parkinsonian medication, medication for
insomnia, anti-depressants, anti-anxiety medication.
- Presence of any metal in the eye or skull area such as a brain stimulator, shrapnel,
surgical metal, clips in the brain, cochlear implants, metal fragments in the eye.
- Presence of pacemaker, intracardiac lines, implanted pumps or stimulators.
- Known hearing loss.
- Cognitive impairment.
- NIH staff from HMCS.
We found this trial at
1
site
9000 Rockville Pike
Bethesda, Maryland 20892
Bethesda, Maryland 20892
301-496-2563
Phone: 800-411-1222
National Institutes of Health Clinical Center The National Institutes of Health (NIH) Clinical Center in...
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