Abstract
Purpose::
To test the concordance across sessions of fMRI data with 5 paradigms in normally sighted subjects and patients with macular disease.
Methods::
We recruited 10 normally sighted subjects (7 males, 3 females; age range, 23 to 70 years), and five patients (1 male, 4 females; age range, 44 to 82 years) with macular disease due to age-related macular degeneration (3) or Stargardt disease (2). Subjects performed the 5 tasks during fMRI with a 3.0 Tesla scanner (GE Healthcare, Waukesha, WI). The five eye movement paradigms were: 1) a visually guided dot saccade task; 2) a smooth pursuit task; 3) a letter saccade task where a letter moved and changed unpredictably, with a finger switch response required when the letter changed to a vowel; 4) a 3 letter word recognition task; and, 5) a 6 letter word recognition task. Subjects performed these tasks in the scanner on three separate sessions. Brain activation patterns were analyzed using NIVANA 2.5 analysis software (MRIx Technologies, Bannockburn, IL) by separating the whole brain into 4 regions of interest (ROIs); frontal lobe, parietal lobe, temporal lobe, and occipital lobe. The percentage of activation for each lobe was calculated. For each paradigm, intra-class correlations were performed for each ROI between sessions to identify the reproducibility of activation patterns.
Results::
The intra-class correlations ranged from 0.34 to 0.69, p’s < 0.05 for the frontal lobe, 0.48 to 0.82, p’s < 0.01 for the parietal lobe, 0.56 to 0.73, p’s < 0.005 for the temporal lobe, and 0.67 to 0.86, p’s < 0.001 for the occipital lobe.
Conclusions::
These findings show that fMRI cortical activation patterns are reproducible in normal individuals and patients across multiple testing sessions with potential for measuring outcomes of vision rehabilitation. The highest reliability was found for the temporal and occipital lobes, which was consistent with the nature of the tasks.
Keywords: visual cortex • neuro-ophthalmology: cortical function/rehabilitation • retinal degenerations: hereditary