The usefulness of the blink reflex in the early diagnosis of cranial nerve neuropathy associated with diabetes mellitus

BACKGROUND: Electrophysiological testing can be of value in early diagnosis of diabetic neuropathy. Limited data is available in the use of the blink reflex (BR) in diabetes mellitus (MD). AIM: is to evaluate the efficacy of BR in early diagnosis of cranial nerve neuropathy in DM. MATERIALS AND METHODS: 67 diabetes and 32 healthy controls-age and sex matched- were chosen. The diabetes were of type I and type II and of more than or less than 10 years duration. The BR was elicited by stimulation the supraorbital nerve using the Dantec Neuromatic 2000M machine. The latency of the components response recorded as R1, R2y (ipsilateral) and R2c (contralateral). A direct response was achieved by the stimulation of the facial nerve; a square wave of 200 msec. was used. RESULTS: No differences were noted when the two sides were compared in diabetic patients, while the difference was highly significant in the increased latency of R1, R2y and R2c each type of diabetes as compared to the control. Comparison of the types and duration of diabetes between each other showed no significant difference. Direct measurement of the latency response of the facial nerve gave a response in diabetics of both types and duration. CONCLUSION: the BR can be useful in the early diagnosis of diabetic neuropathy.