BlindnessNCT00059189
Brain Plasticity of Verbal Memory in the Blind
An observational study of Blindness, run by National Institute of Neurological Disorders and Stroke (NINDS) at 1 site in United States.
Trial summary
This study will examine whether blind people develop changes in the brain that improve memory function. Previous studies have shown that blind people, on average, perform better in memory tasks than sighted people. Read more about this study
- Who is it for?
- Any ageHealthy volunteers can take part
- Conditions the study is for
- Blindness
- What is being tested?
- Magstim Rapid Magnetic Stimulator
- Type of treatment
- Medical device
- How many people
- 85 participants
- Where
- 1 siteUnited States
- Study dates
- Apr 2003to Apr 2005
- 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 Any age
- All sexes
- Healthy volunteers accepted
- Child, Adult, Older adult
Who may be able to join
- Blind Subjects: Early and late blind subjects (aged 18 or over) will be included in this protocol. Handedness will be assessed by the Edinburgh inventory scale. All experimental sessions will be studied on outpatient basis.
- Sighted Subjects: Healthy sighted (normal or corrected-to normal vision) matched in age, sex and level of education to the blind subjects. Handedness will be assessed by the Edinburgh inventory scale.
Who cannot join
- Exclusion criteria for the study will be any current medical or surgical condition or psychiatric or neurological illness. Furthermore, any individual who is on medication with potential influence on nervous system function, who has a history of surgery with metallic implants or known history of metallic particles in the eye, cardiac pacemaker, intracardiac lines, neural stimulators, cochlear implants, pregnancy, or history of drug abuse, will be excluded from the study.
Trial locations and contacts
1 site in 1 country.
United States1 site
National Institute of Neurological Disorders and Stroke (NINDS)
Bethesda, Maryland, 20892
About this study
Official title: Cross-Modal Plasticity of Verbal Memory in the Blind
This study will examine whether blind people develop changes in the brain that improve memory function. Previous studies have shown that blind people, on average, perform better in memory tasks than sighted people. A possible reason for this is that parts of the brain that process visual information in sighted individuals are engaged in processing mnemonic (remembering) information in blind people.
Blind and sighted people 18 years of age and older are eligible for this study. Healthy, sighted individuals may participate in Part 1 of the study, which is designed to find appropriate words to use in tests for Part 2 of the study. Part 2 will include sighted people and blind people. It will examine whether the (visual) brain in blind people is processing mnemonic information in a way that helps with day-to-day memory functions. Blind participants in this study must have lost their sight by age 4. Candidates will be screened with a medical interview and examination and a brief test of short-term and long-term verbal memory. Sighted patients will also be tested for visual memory and for handedness.
Read more
Part 1 - Word Recognition Testing (2 sessions)
- Session 1: Participants listen to a number of words over a loudspeaker and try to remember them for a memory test that will be given 30 minutes later. For the test, subjects listen to words again and press one of three buttons as quickly as possible after hearing the word. The buttons signal whether the subject does or does not recognize the word with a 1) high level of confidence or 2) low level of confidence.
- Session 2: Participants hear a noun over a loudspeaker and have to find an appropriate verb for it, such as the verb (read) for the noun (book).
Part 2 - MRI Scanning and TMS Experiments (5 - 7 sessions)
- Magnetic resonance imaging (MRI): Participants perform the same procedures as described above for Part 1 while undergoing MRI of the brain. For this test, the subject lies on a table inside the MRI scanner - a narrow cylindrical tube with a strong magnetic field. Scanning time varies from 20 minutes to 3 hours, with most scans lasting between 45 and 90 minutes. (Earphones are used to hear the words for this test instead of a loudspeaker.)
- Transcranial magnetic stimulation (TMS): Participants undergo TMS while performing the same procedures described for Part 1. For TMS, a wire coil is held over the scalp. A brief electrical current is passed through the coil, creating a magnetic pulse that stimulates the brain. Subjects may hear a click and feel a pulling sensation on the skin under the coil. There may be a twitch in muscles of the arm or leg. During the TMS, electrical muscle activity is recorded through the electrodes with a computer or other recording device. Each session lasts a maximum of 3 hours.
Read the detailed description
Cross-modal plasticity refers to the concept that the cortex normally responsive to one sensory modality, when deprived of its usual input, becomes responsive to inputs from other sensory modalities. In blind subjects, the visual cortex processes somatosensory and auditory information. A recent functional imaging study found that verbal memory recall and verb generation significantly activated the primary visual cortex in early blind humans. The magnitude of occipital activation was positively correlated with subsequent performance on verbal memory and verb generation tasks. These results raised the untested hypothesis that the primary visual cortex may be the neural substrate mediating superior verbal memory performance in early blind individuals. The purpose of this protocol is to test this hypothesis.
The first experiment will identify the magnitude of activation in cortical areas associated with successful verbal memory encoding and retrieval, and with verb generation, in blind individuals and sighted controls. The expected outcome is increased involvement of the visual cortex in the early blind group. In the second experiment, we will test the hypothesis that disruption of activity of the activated visual cortex (using TMS) will have deleterious effects on verbal memory encoding and verb generation in early blind subjects, but not in late blind subjects nor sighted controls. The TMS experiment is necessary to identify a cause-effect link between occipital activation and improved memory performance.
Experiment 1: We plan to study early blind subjects, late blind subjects and sighted controls during encoding into and retrieval from episodic verbal memory, and during verb generation, using functional magnetic resonance imaging (fMRI). The primary outcome measure will be the number of voxels significantly activated in primary visual cortex in early blind subjects vs. late blind subjects and sighted controls. Experiment 2: We plan to apply rTMS over left primary visual cortex, left prefrontal cortex, and a control site during encoding of words into and retrieval of words from episodic memory (primary task), and during a verb generation task. Sighted volunteers, early blind and late blind subjects will be studied. The primary outcome measure will be performance on a memory test during rTMS applied to different sites in the different groups. This investigation is important because it can provide novel evidence on a hierarchically high function of the primary visual cortex in the blind.
- Conditions
- Blindness
- Being tested
- Magstim Rapid Magnetic Stimulator
- Keywords
- Occipital Cortex, Prefrontal Cortex, Transcranial Magnetic Stimulation, Inhibition, Cortical Excitability, Blindness, Healthy Volunteer, HV
- Medical subject headings
- Blindness, Inhibition, Psychological
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Magstim Rapid Magnetic StimulatorDevice
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted21 Apr 2003 (estimated)
- Study startApr 2003
- Study completionApr 2005
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (3)Papers the sponsor has linked to this study.
- Other trials for BlindnessStudies 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
- 85 participants
Sponsor and investigators
- Sponsor type
- US National Institutes of Health
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT00059189
- Sponsor's protocol ID
- 030163
- Other IDs
- 03-N-0163
- Status last verified
- Apr 2005
- First submitted
- 19 Apr 2003
- Last updated
- 4 Mar 2008
- Results posted
- No
Publications
Alho K, Kujala T, Paavilainen P, Summala H, Naatanen R. Auditory processing in visual brain areas of the early blind: evidence from event-related potentials. Electroencephalogr Clin Neurophysiol. 1993 Jun;86(6):418-27. doi: 10.1016/0013-4694(93)90137-k.
PubMed 7686476Bridgers SL, Delaney RC. Transcranial magnetic stimulation: an assessment of cognitive and other cerebral effects. Neurology. 1989 Mar;39(3):417-9. doi: 10.1212/wnl.39.3.417.
PubMed 2927652Burton H, Snyder AZ, Diamond JB, Raichle ME. Adaptive changes in early and late blind: a FMRI study of verb generation to heard nouns. J Neurophysiol. 2002 Dec;88(6):3359-71. doi: 10.1152/jn.00129.2002.
PubMed 12466452
Study at a glance
From the registry record, last updated by the sponsor on 4 Mar 2008. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Cross-Modal Plasticity of Verbal Memory in the Blind
- ClinicalTrials.gov ID
- NCT00059189
- Acronym / sponsor ID
- 030163
- Conditions
- Blindness
- Keywords
- Occipital Cortex, Prefrontal Cortex, Transcranial Magnetic Stimulation, Inhibition, Cortical Excitability, Blindness, Healthy Volunteer, HV
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 85 participants
- Lead sponsor
- National Institute of Neurological Disorders and Stroke (NINDS)US National Institutes of Health
- Study start
- Apr 2003
- Study completion
- Apr 2005
- First posted
- 21 Apr 2003 (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.
This study will examine whether blind people develop changes in the brain that improve memory function. Previous studies have shown that blind people, on average, perform better in memory tasks than sighted people. A possible reason for this is that parts of the brain that process visual information in sighted individuals are engaged in processing mnemonic (remembering) information in blind people.
Blind and sighted people 18 years of age and older are eligible for this study. Healthy, sighted individuals may participate in Part 1 of the study, which is designed to find appropriate words to use in tests for Part 2 of the study. Part 2 will include sighted people and blind people. It will examine whether the (visual) brain in blind people is processing mnemonic information in a way that helps with day-to-day memory functions. Blind participants in this study must have lost their sight by age 4. Candidates will be screened with a medical interview and examination and a brief test of short-term and long-term verbal memory. Sighted patients will also be tested for visual memory and for handedness.
Part 1 - Word Recognition Testing (2 sessions)
- Session 1: Participants listen to a number of words over a loudspeaker and try to remember them for a memory test that will be given 30 minutes later. For the test, subjects listen to words again and press one of three buttons as quickly as possible after hearing the word. The buttons signal whether the subject does or does not recognize the word with a 1) high level of confidence or 2) low level of confidence.
- Session 2: Participants hear a noun over a loudspeaker and have to find an appropriate verb for it, such as the verb (read) for the noun (book).
Part 2 - MRI Scanning and TMS Experiments (5 - 7 sessions)
- Magnetic resonance imaging (MRI): Participants perform the same procedures as described above for Part 1 while undergoing MRI of the brain. For this test, the subject lies on a table inside the MRI scanner - a narrow cylindrical tube with a strong magnetic field. Scanning time varies from 20 minutes to 3 hours, with most scans lasting between 45 and 90 minutes. (Earphones are used to hear the words for this test instead of a loudspeaker.)
- Transcranial magnetic stimulation (TMS): Participants undergo TMS while performing the same procedures described for Part 1. For TMS, a wire coil is held over the scalp. A brief electrical current is passed through the coil, creating a magnetic pulse that stimulates the brain. Subjects may hear a click and feel a pulling sensation on the skin under the coil. There may be a twitch in muscles of the arm or leg. During the TMS, electrical muscle activity is recorded through the electrodes with a computer or other recording device. Each session lasts a maximum of 3 hours.
Detailed description
Cross-modal plasticity refers to the concept that the cortex normally responsive to one sensory modality, when deprived of its usual input, becomes responsive to inputs from other sensory modalities. In blind subjects, the visual cortex processes somatosensory and auditory information. A recent functional imaging study found that verbal memory recall and verb generation significantly activated the primary visual cortex in early blind humans. The magnitude of occipital activation was positively correlated with subsequent performance on verbal memory and verb generation tasks. These results raised the untested hypothesis that the primary visual cortex may be the neural substrate mediating superior verbal memory performance in early blind individuals. The purpose of this protocol is to test this hypothesis.
The first experiment will identify the magnitude of activation in cortical areas associated with successful verbal memory encoding and retrieval, and with verb generation, in blind individuals and sighted controls. The expected outcome is increased involvement of the visual cortex in the early blind group. In the second experiment, we will test the hypothesis that disruption of activity of the activated visual cortex (using TMS) will have deleterious effects on verbal memory encoding and verb generation in early blind subjects, but not in late blind subjects nor sighted controls. The TMS experiment is necessary to identify a cause-effect link between occipital activation and improved memory performance.
Experiment 1: We plan to study early blind subjects, late blind subjects and sighted controls during encoding into and retrieval from episodic verbal memory, and during verb generation, using functional magnetic resonance imaging (fMRI). The primary outcome measure will be the number of voxels significantly activated in primary visual cortex in early blind subjects vs. late blind subjects and sighted controls. Experiment 2: We plan to apply rTMS over left primary visual cortex, left prefrontal cortex, and a control site during encoding of words into and retrieval of words from episodic memory (primary task), and during a verb generation task. Sighted volunteers, early blind and late blind subjects will be studied. The primary outcome measure will be performance on a memory test during rTMS applied to different sites in the different groups. This investigation is important because it can provide novel evidence on a hierarchically high function of the primary visual cortex in the blind.
Study design
Who may qualify
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Child, Adult, Older adult
Key inclusion criteria (2 listed)
- Blind Subjects: Early and late blind subjects (aged 18 or over) will be included in this protocol. Handedness will be assessed by the Edinburgh inventory scale. All experimental sessions will be studied on outpatient basis.
- Sighted Subjects: Healthy sighted (normal or corrected-to normal vision) matched in age, sex and level of education to the blind subjects. Handedness will be assessed by the Edinburgh inventory scale.
Key exclusion criteria (1 listed)
- Exclusion criteria for the study will be any current medical or surgical condition or psychiatric or neurological illness. Furthermore, any individual who is on medication with potential influence on nervous system function, who has a history of surgery with metallic implants or known history of metallic particles in the eye, cardiac pacemaker, intracardiac lines, neural stimulators, cochlear implants, pregnancy, or history of drug abuse, will be excluded from the study.
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 |
|---|---|---|
| Magstim Rapid Magnetic Stimulator | Device | – |
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 4 Mar 2008.
- Background: PubMed 7686476Alho K, Kujala T, Paavilainen P, Summala H, Naatanen R. Auditory processing in visual brain areas of the early blind: evidence from event-related potentials. Electroencephalogr Clin Neurophysiol. 1993 Jun;86(6):418-27. doi: 10.1016/0013-4694(93)90137-k.
- Background: PubMed 2927652Bridgers SL, Delaney RC. Transcranial magnetic stimulation: an assessment of cognitive and other cerebral effects. Neurology. 1989 Mar;39(3):417-9. doi: 10.1212/wnl.39.3.417.
- Background: PubMed 12466452Burton H, Snyder AZ, Diamond JB, Raichle ME. Adaptive changes in early and late blind: a FMRI study of verb generation to heard nouns. J Neurophysiol. 2002 Dec;88(6):3359-71. doi: 10.1152/jn.00129.2002.
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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 Blindness, 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 1 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 4 Mar 2008. 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 NCT00059189, which also lists 3 linked publications.
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 4 Mar 2008.