Introduction: For the first time visual after-images have been used in patients with Alzheimer's disease (AD). This is a simple, non-invasive system for analysis of visual pathway function, disorders of which it is hoped may be related to the patient's condition.
Objective: To obtain a method for early diagnosis which may also be used for follow-up and evaluation of the disease over a the course of time. We wished to ascertain whether patients with AD have alterations in the perception of visual after-images, and ascertain whether use of after-images is effective.
Patients and methods: We used a portable perimeter for post-images in 20 patients with Alzheimer's disease and in 20 normal persons. The results of two different tests were analysed, measuring the time taken for the after-image to disappear from the visual field of those being examined and trying to detect whether there was a relationship between the state of the person and the results of the test. It was shown statistically that the time taken for the after-image to disappear was less in the patients than in healthy persons, and this rapid rate of disappearance is directly related to the severity of the disease.
Conclusion: We consider that the use of after-images is simple, effective and useful for early diagnosis and confirmation of patients with EA and their follow-up.