Short latency visual evoked potentials in occupational exposure to organicsolvents

Objectives. Short latency visual evoked potentials (SVEP). in response to h igh-intensity flashes from light emitting diodes (LED). were used to detect subclinical effects along the visual pathway in four groups of subjects wi th different levels of exposure to gasoline. all within legally acceptable limits. Methods. Potentials and exposure levels were obtained from 31 subje cts with different occupational exposure levels to gasoline fumes. as well as from 17 non-exposed control subjects. SVEP were recorded from four elect rode sites (infra-orbital. C-z, P-z, O-z). in response to flashes presented to each eye in turn from goggle-mounted LEDs. SVEP components were defined after digital filtering. which eliminated the high-frequency oscillatory p otentials and accentuated five major components: a periocular P-30, attribu ted to the retina: a fronto-central N-50, attributed to the optic nerve. ce ntro-parietal P-65 and N-85, attributed to the optic tracts and radiation: and an occipital. cortical P-105. Results. The latencies of successive SVEP components of the exposed subjects showed a significant latency prolongati on compared to controls. beginning with activity attributed to the optic ne rve and increasing cumulatively with the later components. Retinal componen ts were not affected by the exposure to organic solvents. Among the exposed groups. differences in latency prolongation corresponded to occupational e xposure. Conclusion. The low-frequency components of SVEP were reliably mea sured and proved to be sensitive to subclinical effects of organic solvents on conduction along the visual pathway. These components are likely to be sensitive to other subcortical visual pathway lesions. but their clinical p romise needs further verification. (C) 2000 Editions scientifiques et medic ales Elsevier SAS.