Pupillary dilatation test and Fourier analysis of pupillary oscillations in patients with multiple sclerosis.

Recently we investigated 29 patients aged between 31 and 60 years with multiple sclerosis by means of two new techniques. The first technique was based on pupillary dilatation response to the topical application of the cholinergic antagonist tropicamide. The second technique was the Fourier analysis of pupillary oscillations for measurement of central activation, carried out without and under the influence of a cognitive task. The multiple sclerosis group had a pupillary dilatation of 31.9% after 40 min. Under the influence of a cognitive task the patient group revealed lower amplitudes of pupillary oscillations reflecting a decreased capacity for cognitive activation.