Color visual evoked potentials in children with type 1 diabetes: Relationship to metabolic control

PURPOSE. To examine the association between metabolic control (HbA _1c) and the chromatic mechanisms of children with type 1 diabetes (T1D), by using the color visual evoked potential (VEP). METHODS. Fifty children with T1D (age range, 6-12.9 years) and 33 age-matched control subjects were tested. VEPs were recorded by placing five electrodes on the scalp according to the International 10/20 System of Electrode Placement. Active electrodes O1, O2, and Oz were placed over the visual cortex. Short-wavelength (S), and long- and medium-wavelength (LM) color stimuli consisted of vertical, photometric isoluminant (1 cyc/deg) gratings presented in a pattern onset (100 ms)- offset (400 ms) mode. Achromatic vertical gratings were presented at 3 cyc/deg. Primary outcome measure was VEP latency. The relationship between S, LM, and achromatic VEP latency, and HbA_1c was determined by ANCOVA regression. RESULTS. S-, LM-, achromatic VEP latencies were not associated significantly with HbA_1c. Pubertal status, however, was associated significantly (P = 0.0114) and selectively with S-VEP latency. Pubertal children with T1D had delayed (mean delay, 9.5 ms) S-VEP latencies when compared with the prepubertal children with T1D. However, there was no statistically significant difference (P = 0.1573) in the effect of pubertal status on S-VEP latency between the T1D and control groups. CONCLUSIONS. Pubertal status rather than HbA_1c appears to affect selectively the S-VEP latency of preteen children with T1D. Further study is warranted to determine whether the delay in S-VEP latency in pubertal children with T1D changes over time and whether this change could be a predictive marker for future development of background diabetic retinopathy.