VisionNCT00357409
GABA Levels in the Brains of Blind People
An observational study of Vision and Blind, run by National Institute of Neurological Disorders and Stroke (NINDS) at 1 site in United States.
Trial summary
In blind individuals, the occipital cortex becomes capable of processing tactile and auditory information, a phenomenon described as crossmodal plasticity. GABA is the major inhibitory neurotransmitter in the brain and a possible candidate to mediate this form of human plasticity. Read more about this study
- Who is it for?
- Ages 18 to 55 yearsHealthy volunteers can take part
- How many people
- 39 participants
- Where
- 1 siteUnited States
- Study dates
- 11 Feb 2002to 3 Mar 2008
- 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 to 55 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- All subjects must be between 18 and 55 years of age.
- Healthy sighted volunteers. Legally blind subjects with blindness secondary to retinal lesions or eye removal acquired at ages earlier than 4 years old (EARLY) and after 13 years of age (LATE). The rationale for the distinction is based in our previous studies that indicate different magnitude of brain plasticity depending on the age of acquisition of blindness.
Who cannot join
- Pregnant women tested after urine pregnancy test.
- Subjects with metal in the cranium except mouth.
- Subjects with metal fragments from occupational exposure or surgical clips in or near the brain.
- Subjects with blood vessel, cochlear or eye implants.
- Subjects with increased intracranial pressure as evaluated by clinical means.
- Subjects with cardiac or neural pacemakers.
- Subjects with intracardiac lines and implanted medication pumps.
Trial locations and contacts
1 site in 1 country.
United States1 site
National Institutes of Health Clinical Center, 9000 Rockville Pike
Bethesda, Maryland, 20892
About this study
Official title: GABA Levels in the Occipital Cortex of Blind Human Subjects
In blind individuals, the occipital cortex becomes capable of processing tactile and auditory information, a phenomenon described as crossmodal plasticity. GABA is the major inhibitory neurotransmitter in the brain and a possible candidate to mediate this form of human plasticity. We intend to use magnetic resonance spectroscopy (MRS) to measure GABA and hypothesize that GABA levels in the occipital cortex of blind humans will be lower than in sighted controls. Such decrease could possibly mediate compensatory changes in the occipital cortex of the blind.
Objective
Read more
Early blind subjects exhibit better tactile acuity than late blinds or sighted individuals. The purpose of the study is the determine GABA levels in the human occipital cortex after long-term light deprivation (blindness).
Study Population
Our experiments will make use of early blind, late blind, and sighted control subjects.
Design
Subject will be identified and will receive clinical and neurological examinations at the NIH. MRS studies will be performed at NIH MRI Center with 3Tesla Magnet. Each subject head will be positioned in an adjustable holder (designed for minimal motion and maximal comfort) such that a flat coil lay just below the occipital cortex. The sequence has been described before [33]. The individuals who perform the data analysis will be blind to the purpose of the experiments.
Outcome measures
The concentration of GABA from the 14 ml voxel over the visual cortex will be measured. Edited proton spectrum of GABA will be compared with the edited sub spectrum of creatine for a concentration reference.
Read the detailed description
In blind individuals, the occipital cortex becomes capable of processing tactile and auditory information, a phenomenon described as crossmodal plasticity. GABA is the major inhibitory neurotransmitter in the brain and a possible candidate to mediate this form of human plasticity. We intend to use magnetic resonance spectroscopy (MRS) to measure GABA and hypothesize that GABA levels in the occipital cortex of blind humans will be lower than in sighted controls. Such decrease could possibly mediate compensatory changes in the occipital cortex of the blind.
Objective
Early blind subjects exhibit better tactile acuity than late blinds or sighted individuals. The purpose of the study is the determine GABA levels in the human occipital cortex after long-term light deprivation (blindness).
Study Population
Our experiments will make use of early blind, late blind, and sighted control subjects.
Design
Subjects will be identified and will receive clinical and neurological examinations at the NIH. MRS studies will be performed at NIH MRI Center with 3Tesla Magnet. Each subject head will be positioned in an adjustable holder (designed for minimal motion and maximal comfort) such that a flat coil lay just below the occipital cortex. The sequence has been described before. The individuals who perform the data analysis will be blind to the purpose of the experiments.
Outcome measures
The concentration of GABA from the 14 ml voxel over the visual cortex will be measured. Edited proton spectrum of GABA will be compared with the edited sub spectrum of creatine for a concentration reference.
- Keywords
- GABA, Occipital, Vision, Plasticity, MRS, Blind
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted27 Jul 2006 (estimated)
- Study start11 Feb 2002
- Study completion3 Mar 2008
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 VisionStudies of the same condition, open and under way.
- More trials run by National Institute of Neurological Disorders and Stroke (NINDS)The sponsor's other registered studies.
- 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
- Enrolment
- 39 participants
Sponsor and investigators
- Sponsor type
- US National Institutes of Health
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT00357409
- Sponsor's protocol ID
- 020124
- Other IDs
- 02-N-0124
- Status last verified
- 3 Mar 2008
- First submitted
- 26 Jul 2006
- Last updated
- 2 Jul 2017
- Results posted
- No
Publications
Micheva KD, Beaulieu C. Neonatal sensory deprivation induces selective changes in the quantitative distribution of GABA-immunoreactive neurons in the rat barrel field cortex. J Comp Neurol. 1995 Oct 30;361(4):574-84. doi: 10.1002/cne.903610403.
PubMed 8576415
Study at a glance
From the registry record, last updated by the sponsor on 2 Jul 2017. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- GABA Levels in the Occipital Cortex of Blind Human Subjects
- ClinicalTrials.gov ID
- NCT00357409
- Acronym / sponsor ID
- 020124
- Keywords
- GABA, Occipital, Vision, Plasticity, MRS, Blind
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 39 participants
- Lead sponsor
- National Institute of Neurological Disorders and Stroke (NINDS)US National Institutes of Health
- Study start
- 11 Feb 2002
- Study completion
- 3 Mar 2008
- First posted
- 27 Jul 2006 (estimated)
- 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.
In blind individuals, the occipital cortex becomes capable of processing tactile and auditory information, a phenomenon described as crossmodal plasticity. GABA is the major inhibitory neurotransmitter in the brain and a possible candidate to mediate this form of human plasticity. We intend to use magnetic resonance spectroscopy (MRS) to measure GABA and hypothesize that GABA levels in the occipital cortex of blind humans will be lower than in sighted controls. Such decrease could possibly mediate compensatory changes in the occipital cortex of the blind.
Objective
Early blind subjects exhibit better tactile acuity than late blinds or sighted individuals. The purpose of the study is the determine GABA levels in the human occipital cortex after long-term light deprivation (blindness).
Study Population
Our experiments will make use of early blind, late blind, and sighted control subjects.
Design
Subject will be identified and will receive clinical and neurological examinations at the NIH. MRS studies will be performed at NIH MRI Center with 3Tesla Magnet. Each subject head will be positioned in an adjustable holder (designed for minimal motion and maximal comfort) such that a flat coil lay just below the occipital cortex. The sequence has been described before [33]. The individuals who perform the data analysis will be blind to the purpose of the experiments.
Outcome measures
The concentration of GABA from the 14 ml voxel over the visual cortex will be measured. Edited proton spectrum of GABA will be compared with the edited sub spectrum of creatine for a concentration reference.
Detailed description
In blind individuals, the occipital cortex becomes capable of processing tactile and auditory information, a phenomenon described as crossmodal plasticity. GABA is the major inhibitory neurotransmitter in the brain and a possible candidate to mediate this form of human plasticity. We intend to use magnetic resonance spectroscopy (MRS) to measure GABA and hypothesize that GABA levels in the occipital cortex of blind humans will be lower than in sighted controls. Such decrease could possibly mediate compensatory changes in the occipital cortex of the blind.
Objective
Early blind subjects exhibit better tactile acuity than late blinds or sighted individuals. The purpose of the study is the determine GABA levels in the human occipital cortex after long-term light deprivation (blindness).
Study Population
Our experiments will make use of early blind, late blind, and sighted control subjects.
Design
Subjects will be identified and will receive clinical and neurological examinations at the NIH. MRS studies will be performed at NIH MRI Center with 3Tesla Magnet. Each subject head will be positioned in an adjustable holder (designed for minimal motion and maximal comfort) such that a flat coil lay just below the occipital cortex. The sequence has been described before. The individuals who perform the data analysis will be blind to the purpose of the experiments.
Outcome measures
The concentration of GABA from the 14 ml voxel over the visual cortex will be measured. Edited proton spectrum of GABA will be compared with the edited sub spectrum of creatine for a concentration reference.
Study design
Who may qualify
- Ages
- 18 to 55 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (2 listed)
- All subjects must be between 18 and 55 years of age.
- Healthy sighted volunteers. Legally blind subjects with blindness secondary to retinal lesions or eye removal acquired at ages earlier than 4 years old (EARLY) and after 13 years of age (LATE). The rationale for the distinction is based in our previous studies that indicate different magnitude of brain plasticity depending on the age of acquisition of blindness.
Key exclusion criteria (7 listed)
- Pregnant women tested after urine pregnancy test.
- Subjects with metal in the cranium except mouth.
- Subjects with metal fragments from occupational exposure or surgical clips in or near the brain.
- Subjects with blood vessel, cochlear or eye implants.
- Subjects with increased intracranial pressure as evaluated by clinical means.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Primary outcome
Not reported in the source record.
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 2 Jul 2017.
- Background: PubMed 8576415Micheva KD, Beaulieu C. Neonatal sensory deprivation induces selective changes in the quantitative distribution of GABA-immunoreactive neurons in the rat barrel field cortex. J Comp Neurol. 1995 Oct 30;361(4):574-84. doi: 10.1002/cne.903610403.
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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 Vision and Blind, run by National Institute of Neurological Disorders and Stroke (NINDS) at 1 site in United States.
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 2 inclusion and 7 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 2 Jul 2017. 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 States. 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.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT00357409, 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 2 Jul 2017.