Timed repetitive ankle jerk responses in early diabetic neuropathy.

A 14-year experience with timed repetitive ankle jerk (TRAJ) testing provides fundamental insights into diabetic neuropathy (DN), both its diagnosis and treatment. Advantages of TRAJ include ease of performance, relative economy of the equipment, reproducibility of results, and a parameter that encompasses the entire reflex arc. Euthyroid patients with features suggesting DN often have prolongation of ankle jerk responses on one or both sides only after repetitive stimulation. Prolongation of TRAJ responses were elicited from 41% of overt diabetics and from 27% and 30% of patients with decreased glucose tolerance demonstrated by morning or afternoon testing, respectively. This characteristic response appears to reflect altered neuromuscular function in DN and was not encountered in patients with myasthenia gravis or thyroid dysfunction in the absence of concomitant glucose metabolic aberrations.