The blink reflex in chronic renal failure.

The components of the electrically elicited blink reflex were investigated in 15 patients who were admitted to a chronic dialysis program because of chronic renal insufficiency with serum creatinine concentrations from 6.0 to 14.2 mg/dl. In addition, the conduction time in the facial nerve, the motor conduction velocities, and the distal motor latencies of the median and peroneal nerves were measured. In 13 of 15 patients (87%) there was at least one component of the blink reflex pathologically delayed. Bilateral prolongation of the latency of the component R1 was seen most frequently. In all pathological cases the distribution pattern of the responses revealed dysfunction in the brainstem. Correlating the values of blink reflex latencies, the period of dialysis, the values of serum creatinine and urea nitrogen, and the results of peripheral neurography, there was a significant relationship between the motor conduction velocity of the peroneal nerve and the latency of the early component R1. The value of these findings in reference to the known neurological symptomatology in chronic renal failure is discussed.