Effects of Prism Adaption and rTMS on Brain Connectivity and Visual Representation
| Status: | Recruiting |
|---|---|
| Conditions: | Healthy Studies, Neurology |
| Therapuetic Areas: | Neurology, Other |
| Healthy: | No |
| Age Range: | 18 - 75 |
| Updated: | 8/18/2018 |
| Start Date: | September 21, 2016 |
| End Date: | May 31, 2019 |
| Contact: | Selene Schintu |
| Email: | schintus@mail.nih.gov |
| Phone: | (301) 496-5829 |
Background:
After a stroke, the balance between the two halves of the brain can be lost. This may cause
people to lose the ability to perceive a side of space. This is called neglect. Having people
wear prism glasses (called PA) can reduce neglect symptoms. Researchers want to find out more
about how PA, and whether it restores the balance in the brain.
Objective:
To learn how prism adaption temporarily changes vision and connections in the brain.
Eligibility:
People ages 18 75 with brain damage of the right side of the brain from a stroke or other
cause, leading to neglect.
Healthy volunteers ages 18 75.
Design:
Participants will have 1 3 visits.
Participants will be screened with a neurological exam. They may also have:
Tests of thinking and vision
Tests to see which eye and hand they prefer
A pregnancy test
All participants will:
Answer questions about their personality, style of thinking, and beliefs.
Do simple tasks on paper or computer
Have magnetic resonance imaging. They will lie on a table that can slide in and out of a
cylinder in a strong magnetic field. Participants will lie still or do computer tasks in the
scanner.
Participants may also have:
Transcranial magnetic stimulation. A brief electrical current passes through a wire coil on
the scalp. This creates a magnetic pulse that affects brain activity. Participants may be
asked to tense certain muscles or perform simple actions or tasks.
PA. They will sit in front of a board and point to a dot on it while they wear prism glasses
that shift vision to the left or right.
After a stroke, the balance between the two halves of the brain can be lost. This may cause
people to lose the ability to perceive a side of space. This is called neglect. Having people
wear prism glasses (called PA) can reduce neglect symptoms. Researchers want to find out more
about how PA, and whether it restores the balance in the brain.
Objective:
To learn how prism adaption temporarily changes vision and connections in the brain.
Eligibility:
People ages 18 75 with brain damage of the right side of the brain from a stroke or other
cause, leading to neglect.
Healthy volunteers ages 18 75.
Design:
Participants will have 1 3 visits.
Participants will be screened with a neurological exam. They may also have:
Tests of thinking and vision
Tests to see which eye and hand they prefer
A pregnancy test
All participants will:
Answer questions about their personality, style of thinking, and beliefs.
Do simple tasks on paper or computer
Have magnetic resonance imaging. They will lie on a table that can slide in and out of a
cylinder in a strong magnetic field. Participants will lie still or do computer tasks in the
scanner.
Participants may also have:
Transcranial magnetic stimulation. A brief electrical current passes through a wire coil on
the scalp. This creates a magnetic pulse that affects brain activity. Participants may be
asked to tense certain muscles or perform simple actions or tasks.
PA. They will sit in front of a board and point to a dot on it while they wear prism glasses
that shift vision to the left or right.
OBJECTIVES:
The ability to efficiently select information from the environment relies on a balanced
interaction between the right and left hemispheres. Hemispatial neglect, most frequently
following damage to the right hemisphere, has been hypothesized to result from the breakdown
of this interhemispheric balance. There is evidence from transcranial stimulation studies
that the breakdown of this interhemispheric balance is reflected in fronto-parietal
connectivity. The primary goal of this study is to test whether altering the balance between
the left and right hemispheres, with repetitive transcranial magnetic stimulation (rTMS) or
prism adaptation (PA), will affect functional connectivity measured with functional magnetic
resonance imaging (fMRI). We will also explore the relationship between the changes in
functional connectivity and behavioral performances.
STUDY POPULATION: Healthy adult volunteers and patients with neglect after a right hemisphere
damage.
DESIGN: The study contains three experiments. Experiment 1 is designed to investigate the
mechanism of the changes induced by PA in both resting state functional connectivity in
neglect patients and healthy volunteers (a two-arm parallel study). Experiment 2 is designed
to investigate the mechanism of the changes in resting state functional connectivity induced
by lPA, rPA, nPA in healthy volunteers with right dominant eyes and lPA in healthy volunteer
with left dominant eye (a four-arm parallel study). Experiment 3 is designed to see if
inhibitory rTMS over the right posterior parietal cortex (PPC) can influence functional
connectivity and visuospatial bias in healthy volunteers (a crossover study).
OUTCOME MEASURES: For all three experiments the primary outcome measure is the change (or
difference) in fronto-parietal resting state connectivity between post and pre PA or rTMS
procedure. The secondary outcome measures are the changes in visual field representation and
in visuo-motor and cognitive behavior accompanying these manipulations.
The ability to efficiently select information from the environment relies on a balanced
interaction between the right and left hemispheres. Hemispatial neglect, most frequently
following damage to the right hemisphere, has been hypothesized to result from the breakdown
of this interhemispheric balance. There is evidence from transcranial stimulation studies
that the breakdown of this interhemispheric balance is reflected in fronto-parietal
connectivity. The primary goal of this study is to test whether altering the balance between
the left and right hemispheres, with repetitive transcranial magnetic stimulation (rTMS) or
prism adaptation (PA), will affect functional connectivity measured with functional magnetic
resonance imaging (fMRI). We will also explore the relationship between the changes in
functional connectivity and behavioral performances.
STUDY POPULATION: Healthy adult volunteers and patients with neglect after a right hemisphere
damage.
DESIGN: The study contains three experiments. Experiment 1 is designed to investigate the
mechanism of the changes induced by PA in both resting state functional connectivity in
neglect patients and healthy volunteers (a two-arm parallel study). Experiment 2 is designed
to investigate the mechanism of the changes in resting state functional connectivity induced
by lPA, rPA, nPA in healthy volunteers with right dominant eyes and lPA in healthy volunteer
with left dominant eye (a four-arm parallel study). Experiment 3 is designed to see if
inhibitory rTMS over the right posterior parietal cortex (PPC) can influence functional
connectivity and visuospatial bias in healthy volunteers (a crossover study).
OUTCOME MEASURES: For all three experiments the primary outcome measure is the change (or
difference) in fronto-parietal resting state connectivity between post and pre PA or rTMS
procedure. The secondary outcome measures are the changes in visual field representation and
in visuo-motor and cognitive behavior accompanying these manipulations.
- INCLUSION CRITERIA:
Inclusion Criteria for all participants:
All participants must have had a neurological examination by a NINDS physician within the
last two years, a clinical MRI within the last year, and be able to read, write and speak
English.
Experiment 2 requires 63 healthy volunteers having right dominant eye and 21 volunteers
having left dominant eye. Therefore, healthy volunteers with left dominant eye will be
recruited until the necessary number is reached. We estimate we will have to screen 150
healthy volunteers. Participants for whom the study was not completed due to technical
problems and who did not undergo prism adaptation or TMS will be retested and data from the
incomplete session will not be analyzed.
A-Inclusion Criteria for Healthy volunteers/Age-matched Controls
Experiment 1
- Age 18-75 (inclusive; we will try to match this to the stroke group)
- Montreal Cognitive Assessment score greater than or equal to 26
- Absence of neglect at time of testing (Diller test score less than or equal to 2)
Experiments 2 and 3
- Right-handedness
- Age 18-35 (inclusive)
- Twelve or more years of education
- Are able to see a dot of size 0.2 inches at a distance of 22.5 inches without glasses
or with contact lenses (only for Experiment 2)
B-Inclusion Criteria for Patients
Experiment 1
- Age 18-75 (inclusive)
- Montreal Cognitive Assessment score greater than or equal to 26
- A right hemisphere stroke or other focal, non-progressive, brain lesion resulting in
neglect
- Minimum of 30 days from lesion onset to testing
- Evidence of neglect at time of testing (Diller test score greater than or equal to 5)
EXCLUSION CRITERIA:
A- Exclusion Criteria for Healthy volunteers
- Significant illness affecting the central nervous system
- History of seizure (for Experiment 3)
- Inability to give informed consent
- Concurrent use of sedating medications
- Trained to write in other than left to right direction
- Ferromagnetic metal in the cranial cavity or eye, e.g. aneurysm clip, implanted neural
stimulator, cochlear implant, or ocular foreign body
- Implanted cardiac pacemaker or auto-defibrillator or pump
- Non-removable body piercing
- Claustrophobia
- Inability to lie supine for 1.5 hour
- Pregnancy
- Members of the NINDS Behavioral Neurology Unit (BNU)
B- Exclusion Criteria for Patients and Age-matched Controls:
- Significant illness affecting the central nervous system, other than right hemisphere
lesion causing neglect in patients
- Inability to give informed consent
- Concurrent use of sedating medications
- Ferromagnetic metal in the cranial cavity or eye, e.g. aneurysm clip, implanted neural
stimulator, cochlear implant, or ocular foreign body
- Implanted cardiac pacemaker or auto-defibrillator or pump
- Non-removable body piercing
- Claustrophobia
- Inability to lie supine for 1.5 hour
- Pregnancy
- Members of the NINDS Behavioral Neurology Unit (BNU)
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...
Click here to add this to my saved trials
