Study of anatomic location of blink reflex arch in patients with hemispheric strokes

Introduction: Blink reflex (BR) is a new electro diagnostic test mediated through a reflex arch with fifth cranial nerve in its afferent and seventh cranial nerve in its efferent side. BR responses are designed R1 , R2 and R2c responses. Anatomic locations of this reflex arch in central nervous system are still undefined and various results have been reported in different studies, for example in hemispheric strokes, exclusive abnormalities of R2 responses or abnormalities in both R1 and R2 (unilateral or bilateral) have been reported. Materials and Methods: Twenty patients with hemispheric strokes were evaluated during 1.5 year period and were compared with age and sex matched normal volunteers. BR was performed in similar circumstances in both groups and results were compared with each other. Findings: BR was abnormal in 19 patients and was normal in only one patient. R1 response was normal in 18 patients and was prolonged in two patients. R2 response was absent or prolonged in 18 patients (in 15 patients bilaterally) and was normal in two patients. The most prevalent observed risk factors in the study population were Hypertension and Diabetes mellitus respectively. Conclusion: BR was abnormal in 95% of the patients and R2 response abnormalities were detected in 90% of the patients (Bilateral in 75%). The most common observes pattern of BR abnormalities in hemispheric strokes was bilateral absence or prolongation of R2 responses.