Attention and Visual Perception

Completed

Conditions studied: Focal Lesions, Focal Brain Lesion

In brief

The NIMH is conducting studies aimed at gaining a better understanding of the areas of the brain that are involved in different types of mental processes. This study will focus on brain regions involved in visual perception and attention. Healthy normal volunteers and people who have had a stroke or undergone neurosurgery may be eligible for this study. Candidates must be 18 years of age or older, They must not have a history of a psychiatric disorder, including depression, anxiety, psychosis, or neurological disease other than stroke or the previous neurosurgery. Participants undergo the following tests and procedures during four or more visits to the NIH Clinical Center: * Physical and neurological examinations and depression rating scale. * Cognitive testing: Subjects complete written tests, sit at a computer and make decisions about what they are shown by pressing keys, or answer questions from a test examiner. * Behavioral training: Subjects practice performing a cognitive task that involves looking at and making decisions about visual images that appear on a computer screen. * Magnetic resonance imaging (MRI): Subjects undergo MRI scanning while they perform the task they previously practiced. The MRI scanner is a metal cylinder surrounded by a strong magnetic field. During the procedure, subjects lie still for up to 10 minutes at a time on a table that can slide in and out of the cylinder. The entire MRI scanning session takes about one hour. There are multiple scans which each can take up to 10 minutes. They may be asked to return for one or two additional scanning sessions. During the behavioral training or MRI scanning, special pieces of equipment that monitor eye movements may be used. Some subjects may be asked to return to NIH for an additional visit to participate in a magnetoencephalographic scan. This test uses several sensors applied to the scalp to measure very small changes in magnetic fields. This is another way to measure brain activity.

Key facts

Study ID

NCT00111293

Run by

National Institute of Mental Health (NIMH)

People needed

8

Starts

2005-05-16

Expected to finish

2010-05-14

Last updated by the study team

2017-07-02

Who can join

Age: 18 and older, up to 80. Sex: any. Healthy volunteers: accepted.

You may not qualify if…

• The following criteria will be used to exclude patients or healthy volunteers from participation in this study:
• Patients with language impairments that prevent them from understanding our tasks or follow instructions will be excluded.
• Patients with a WAIS-R Full-Scale IQ of less than 75 will be excluded.
• Patients with severe cognitive dysfunction as assessed by the neuropsychological tests.
• Subjects with moderate or severe depression as assessed by the Beck Depression Inventory (scores greater than 18).
• Patients who cannot perform control tasks to the same level of performance as the control subjects will be excluded.
• Subjects with contraindication to MRI scanning will be excluded from any testing which involves the use of MRI. These contraindications include subjects with the following devices or conditions: a) central nervous system aneurysm clips; b) implanted neural stimulator; c) implanted cardiac pacemaker or defibrillator; d) cochlear implant; e) ocular foreign body (e.g., metal shavings); f) insulin pump; g) metal shrapnel or bullet; h) any implanted device that is incompatible with MRI.
• Subjects with a history of any neurological or psychiatric disorder not related to the focal lesion (e.g., epilepsy, schizophrenia, etc.)
• Subjects with any previous head injuries not related to the focal lesion.
• Subjects with a history of drug or alcohol abuse or addiction (determined by a qualified neurologist/psychiatrist).
• Subjects with conditions that preclude entry into the scanner (e.g., morbid obesity, claustrophobia, etc.) will not be included in brain imaging studies.
• Female subjects of child-bearing age will be excluded from brain imaging studies if they are pregnant or refuse to undergo a urine pregnancy test.
• Subjects with visual, auditory, motor, or language problems that would prohibit them from being able to properly perform the visual attention tasks, to understand instructions, indicate their responses, or to communicate with the experimenter via an intercom system.
• Subjects who have undergone radiation treatment or chemotherapy during a one-year period prior to the experiment.

Where it is running

• National Institutes of Health Clinical Center, 9000 Rockville Pike — Bethesda, Maryland, United States

Full record on ClinicalTrials.gov

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