Relationship of Adrenal Cortical Function to Flicker Fusion Thresholds

¹ From the Departments of Medicine and Psychiatry, Harvard Medical School, and the Medical Clinic, Peter Bent Brigham Hospital, Boston, Massachusetts

Flicker fusion thresholds and adrenal steroid levels were observed in normal subjects and in patients with Addison's disease to investigate perceptual acuity and adrenal function. Observations were made without exogenous adrenal stimulation and also after administration of intravenous ACTH and oral Meticorten. In some normal subjects an 8:00 a.m. flicker fusion threshold was correlated with the subsequent 24-hour urinary excretion of 17-hydroxycorticoids. ACTH stimulation prevented the normal diurnal fall in flicker fusion rate. In patients with Addison's disease, the flicker fusion rate increased progressively with higher doses of hormonal replacement until optimal levels were exceeded. A fall in flicker fusion rate sometimes heralded an adrenal crisis.