Visual evoked responses in megaloblastic anemia.

ABSTRACT

Pattern shift visual evoked responses (PSVER) were studied in thirty patients suffering from severe megaloblastic anemia (mean Hb level was 4.25 +/- 1.22 g/dL) of nutritional origin. All patients lacked clinical stigmata of visual and neurologic impairment. Mean P100 latency in thirty age and sex matched controls was 96.35 +/- 6.75 ms (range 86-108 ms) and mean amplitude was 10.37 +/- 3.88 microV (range 4.8-20.8 microV). Mean P100 latency in megaloblastic anemia was 114.77 +/- 11.68 (range 91-142) ms, P < 001 vs. control) and mean amplitude was 8.85 +/- 2.8 microV (range 5.1-16.2 microV). Seventy percent cases had prolonged latency of P 100. After correction of anemia with therapeutic doses of vitamin B12 and folic acid in three months (mean Hb level was 12.08 +/- 1.86 g/dL), the mean P100 latency was 105.13 +/- 9.30 ms (range 92-121 ms P < 0.001 vs. controls) and mean amplitude was 10.72 +/- 4.13 microV (range 5.1-21.4 microV). There was significant improvement in P100 latency after correction of anemia (P < 0.01). There was a negative correlation between P100 latency and hemoglobin levels, though it was statistically not significant.