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Aims: The aim of this study was to test the utility of blink reflex in detecting sub-cranial neuropathy in the early course of Guillain Barre syndrome (GBS).
Study Design: The study was a case control study with 5 clinically diagnosed patients of GBS and 5 age and sex matched healthy controls.
Place and Duration of Study: Department of Physiology, Pt. B.D. Sharma, Rohtak, Haryana, India. The duration was six months.
Methodology: A total of 5 patients (4 men, 1 women; age range 9-70 years) clinically diagnosed patients of GBS in 1st week of illness, sent for electro-diagnostic evaluation to the department of Physiology from the department of Medicine were included. Motor conduction studies (median, ulnar, tibial & peroneal), sensory conduction studies (median & sural nerves), F wave studies and blink reflex analysis were carried out on both cases and 5 healthy controls.
Results: Out of the Five patients, four had decreased conduction velocity (CV) & amplitude for median & ulnar nerves while 1 patient had normal CV & amplitude. Three patients had a decrease in CV & amplitude for tibial & peroneal nerves; one patient had decreased CV & amplitude for tibial nerve while one had conduction block for both nerves. Decreased sensory CV was seen in all 5 patients in the upper limb; while 3 had normal sural nerve CV. Two patients had decreased sural nerve velocity. F wave was completely absent (prolonged F wave latency) in 3 patients in the upper limb; in 2 cases it was decreased. In the lower limb, f wave was completely absent. A statistically significant increase in R1 latency of blink reflex was seen in all 5 patients on both right & left sides. Increased latency of R2 (ipsilateral) & R2 (contralateral) were also seen.
Conclusion: The abnormalities of blink reflex most likely represent demyelination in either the facial and/or the trigeminal nerves reflecting the multifocal nature of demyelination in GBS. So blink Reflex can be a useful tool for detection of clinically silent cranial neuropathy in GBS.