Clinical application of visual evoked potentials in evaluation of the visual system in cerebral palsy. Studies on different modes of stimulation
Galas-Zgorzalewicz, B.; Zgorzalewicz-Stachowiak, Młgorzata.; Bartkowiak, Z.
Przeglad Lekarski 67(9): 702-705
2010
ISSN/ISBN: 0033-2240 PMID: 21387808 Document Number: 639812
In cerebral palsy (CP), besides the early systematic management of the motor disability, there is also a need for a detection of disturbances of visual capacity. The research aimed at presenting various types of visual evoked potentials (VEP) in evaluation of visual impairment in children with CP. VEPs were registered on 100 children and adolescents, aged 2-19 years, presenting spastic type of CP. According to the degree of patient's cooperation VEPs were elicited with checkerboard pattern reversal (PR), light emitting diodes (LEDs) goggles and flashing screen (F) stimulation. They were recorded by means of Multiliner (Toennies, Germany). Latencies of maximum positive deflection P100, predicting N75 component and following N145 as well as amplitudes of N75/P100 and P1001 N145 were analyzed. The results of VEP obtained in the study group were compared with data recorded from healthy subjects of matched age and sex. The patients were subject of ophthalmological examination prior to electrophysiological testing. Visual acuity ranged from apparently normal to lowered acuity of various degrees. Refractive errors appeared mostly in the form of hyperopia. The study showed that in children with CP, who underwent PR and F stimulation, the latencies of the N75, P100, N145 deflections were significantly longer and the amplitudes were shorter than in the control group. In case of LED stimulation only prolongation of P100 deflection reached statistically significant value in patients. Our results indicate that VEPs are objective noninvasive and reproducible means which enable assessment of the functional state of visual system in CP. The data of the present study support the role of VEP in identification of visual impairment that can be an important complementary tool in ophthalmological examination.