The influence of attention on visual evoked potentials in normal adults and dementias

In normal subjects (n = 58, 22-71 y) the influence of the attention level on the VEP latency is studied, as is done in an additional small group of dementias (n = 14). The motor reaction time test (MRT) was selected to measure the attention level. The MRT was administered simultaneously with the VEP (checkerboard pattern reversal). By comparing VEP in test and non-test situations it proved that administration of MRT during VEP examination does not influence the VEP latencies. In dementias the motor reaction time is delayed but the degree of MRT delay did not correlate with the VEP latencies. This holds true for healthy volunteers as well as for demented patients. It is thus concluded that the latency increase of the late peaks of the VEP in dementias cannot be attributed to attentional deficits.