Age-Related Macular Degeneration: the Effect of Training on Visual Performance and Neural Activity

Kristina Visscher, Ph.D.

University of Alabama School of Medicine

Grant Program:

David Mahoney Neuroimaging Program

Funded in:

December 2010, for 3 years

Funding Amount:

$200,000

Lay Summary

Determining how vision can be improved in patients with macular degeneration

Investigators will determine how macular degeneration modifies visual activity in the brain, and how this activity is further modified by training designed to increase the speed of patients’ cognitive processing.

About two million older adults have an advanced stage of macular degeneration. The disorder causes them to lose the ability to see in the center of their visual field, including parts of the eye’s retina called the “macula.” Ordinarily, this area is responsible for our visual ability to read, recognize faces and scrutinize objects and scenes. The visual information is passed on to the brain’s primary visual cortex, where it is processed. While macular degeneration destroys this key visual field, patients retain vision in the outer part of the retina. Many patients are able to compensate by using these spared visual areas, while others are not. The reasons for this disparity are not clear. Prior research in patients, however, indicates that a specific area of the brain’s primary visual cortex, called the “lesion projection zone,” remains active even though it receives no information from the retina. Activity in this zone may account for the ability by many patients with macular degeneration to compensate for their visual loss. The investigators, therefore, will use fMRI imaging to explore how macular degeneration modifies neural activity in the lesion projection zone, and how this neural activity is further modified by cognitive training.

They hypothesize that: (1) patients undergo remapping of their visual cortex, which represents development of alternative ways to focus attention; (2) standardized training designed to speed the pace of patients’ cognitive processing further modifies these neural changes; and (3) the extent to which patients improve their performance on visual tasks will correlate with the extent of the changes in the visual cortex that improve attention and also produce stronger connections with the brain’s motor cortex. Using fMRI imaging in 24 adults with macular degeneration and 24 healthy volunteers, they will first determine whether patients’ visual cortex has undergone visual remapping. Then, 12 of the patients will participate in a standardized cognitive training regimen designed to increase the speed at which they process cognitive information. All 24 patients will then be re-imaged, and investigators will determine whether the trained patients perform better on visual tasks compared to the untrained patients, and whether their improved performance is correlated with further changes in function in their visual cortex.

Significance: The research could lead to methods to tailor cognitive training to the needs of each individual patient with age-related macular degeneration to maximize residual visual skills.

Investigator Biographies

Kristina Visscher, Ph.D.

1982-1985 Ophthalmology Residency: University of Saskatchewan, Saskatoon, Canada.

1985-1986 Retina Fellowship: Presbyterian Medical Center, Denver, CO.

1986-1987 Low Vision Rehabilitation Fellowship: Pacific Medical Center, San Francisco, CA.

1992-1995 Assistant Professor: University of Missouri, Kansas City; Ophthalmology.

1992-1995 Adjunct Associate Professor: University of Kansas; Allied Health, Occupational Therapy.

1995-2001 Clinical Associate Professor: University of South Florida, Tampa; Ophthalmology.

1996-pres. Adjunct Clinical Associate Scientist: Schepens Eye Research Institute, Boston.

2000-2004 Associate Professor: University of Alabama, Birmingham; Ophthalmology.

2004-present Scientist (Affiliate): The Smith-Kettlewell Eye Research Institute, San Francisco.

2004-present Full time faculty: California Pacific Medical Center, San Francisco; Ophthalmology.

2009-present Adjunct Associate Professor: University of Kansas, Dept. of Ophthalmology, Kansas City

Honors

Recipient: Honor Award and Senior Achievement Award, American Academy of Ophthalmology (AAO).

Recipient: Meritorious Award for Outstanding Lifetime Contributions to Low Vision, Association for Education and Rehabilitation of the Blind and Visually Impaired (AER).

Past-member: Ophthalmic Practice Committee, AAO.

Past-chair: Low Vision Rehabilitation Committee, AAO.

Past-member: NEI’s Visual Impairment & Rehabilitation Panel.

Member: Editorial Board, Retinal Physician, 2005 to present.

Member: Professional Issues Committee, (AER), 2006 to present.

AAO representative: American Congress of Rehabilitation Medicine.

Advisor: National Eye Health Education Program.

Member: Scientific Advisory Board, Helen Keller Eye Research Foundation.

Board of Directors: Oakland Lions Blind Center

Participant: volunteer medical work in Africa, South America and Asia.