Abstract
Purpose: :
The goal of this study was to gain pilot data on whether the Welch Allyn Frequency Doubling Technology (FDT2 model) is sensitive to early/preclinical stages of Alzheimer’s disease (AD).
Methods: :
A cross-sectional study design was employed to compare the FDT test variables between healthy controls, mild AD patients and amnestic AD patients. 6 mild AD patients, 6 amnestic MCI patients and 6 healthy controls were recruited for the study. After exclusions and re-testing, 5 patients with early AD, 4 patients with amnestic MCI and 5 healthy demographically comparable older controls. Many participants were examined twice to address technical issues and confirm initial results.
Results: :
The FDT2 data were analyzed independently by two groups. Analysis by one statistician indicated that several variables appeared promising as discriminators of the three diagnostic groups (AD, MCI, HC-healthy controls): AD v. HC: test time (p=0.0031), peripheral/central (p=0.0034), mean deviation (average loss of entire field) (p=0.0118), and pattern standard deviation (irregularity in visual field) (p=0.0128).
Conclusions: :
The variables of average loss of entire visual field, irregularity in the visual field and test taking time appear promising as discriminators of AD, MCI and HC. A further phase of the study will increase the number of participants to be sufficient for multivariate analysis. It was determined that in the next phase of the study a sample of 30 HC, 30 MCI, and 30 early AD would be sufficient for multivariate analysis combining these or other FDT2 features as predictors of class membership.
Keywords: visual impairment: neuro-ophthalmological disease • visual fields