Role of blink reflex in diagnosis of subclinical cranial neuropathy in diabetic mellitus type II.

BACKGROUND AND OBJECTIVES

Peripheral neuropathy (PN) is one of the late complications of diabetes mellitus. Cranial nerves III, VII, and V are among the most commonly affected in diabetic patients. Traditional electrodiagnosis (Edx) studies are a useful method for diagnosis of PN and symptomatic cranial neuropathy, and may not be useful for detecting subclinical involvement of cranial nerves. The main objective of this study is to evaluate the role of blink reflex (BR) for early diagnosis of cranial neuropathy in diabetic patients with PN.

DESIGN

A prospective study was performed on NIDDM patients with PN. One hundred eighty-eight subjects were included in our study in which 142 acted as healthy subjects and 46 as diabetic patients. Patients were excluded with prior history of cranial nerve lesions, stroke, or any other disease with polyneuropathy or drug-induced neuropathy. Routine nerve conduction studies were performed, and only patients with PN were included in this study.

RESULTS

Abnormalities were found in 54.4% of patients. R1, IR2, and CR2 were prolonged relative to the healthy group. Statistically there was no significant difference in R/D ratio of patients (P=0.201). Also, there was a positive correlation between R1, IR2, and CR2 latencies with duration of diabetes and severity of polyneuropathy, but not for R/D. The greatest correlation was shown in R1 latency (69.9% abnormality).

CONCLUSION

BR is a noninvasive and very useful method for the evaluation and diagnosis of subclinical cranial nerve involvement in diabetic patients.