Biomedical subjects
Publications and source records attributed to R Genicot.
The blind from birth has a slower psychomotor development than the normal child because he must palliate the deficiency of visual information by the development of suppletory senses and integrate these information to the structuration of environment. An early assistance by a multidisciplinary team with an important participation of the family will however permit a harmonious development.
OBJECTIVE: To investigate whether colored glasses influence the habituation of visual evoked potentials. BACKGROUND: We have previously shown that during pattern-reversal stimulations lasting 2 minutes the amplitude of the visual evoked potential increases in migraine with and without aura between attacks, whereas it decreases in healthy volunteers. Red light was found to increase visually evoked EEG fast activity only in children with migraine with aura. Wearing rose-tinted glasses for 4 months decreased attack frequency in parallel with a reduction of the visually evoked EEG fast activity. METHODS: We compared the change in amplitude of the visual evoked potential using five different tinted glasses in 12 patients with migraine with aura and in 10 healthy volunteers. During continuous stimulation at 3.1 Hz, five blocks of 50 responses were sequentially averaged using red, yellow, green, blue, and grey glasses and without glasses in a random order and analyzed in terms of latencies and N1-P1 amplitudes. Amplitude changes were calculated for each block by comparison with the first block in every condition and analyzed statistically using Zerbe's method. RESULTS: In healthy volunteers, the visual evoked potential amplitude increased with red glasses compared to without glasses (P = .05) or with green glasses (P = .03). In patients with migraine with aura, no significant difference was detected using colored glasses. Our findings in healthy volunteers are in line with earlier reports of increased excitability of the human visual cortex when exposed to red light. The lack of such a pattern in patients with migraine with aura suggests that the visual cortex is interictally hypoexcitable rather than hyperexcitable, which is consistent with studies of transcranial magnetic stimulation.
Among photosensitive patients, the use of colored filters sometimes leads to a clear improvement of comfort. After a general review of theory, we start on the way we take care of these patients and the way filters are fitted and made. We only present here a preliminary work. A subsequent study or accurate informations of colored filters will be published later. The aim is to set up a methodic procedure in order to find the best selection of the recommended spectral curve and the best way to follow the progress of the patient as regards the wearing and the effect of the filter. An overview of our cases is presented.
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