Diagnostic value of blink reflex in multisystem atrophy, progressive supranuclear palsy and Parkinson disease

Abnormal blink reflex (BR) is a result of reticular brainstem pathways dysfunction and seems to be one of the features of brain degenerative disorders. The aim of the study was to estimate the diagnostic value of blink reflex in neurodegenerative diseases such as: multisystem atrophy (MSA), progressive supranuclear palsy (PSP) and Parkinson disease (PD). Material consisted of 99 patients with clinically probable MSA (51), PSP (28) and PD (20). MSA patients were divided into two subgroups, with dominant cerebellar (MSA-C) and parkinsonian signs (MSA-P). The mean age of patients was 64.9 years (47-79 years); males - 55.3%. Blink reflex was obtained in a typical way.

The significant differences in mean values of blink reflex latencies between PD and other subgroups (MSA-P, MSA-C, PSP) were found, but all of them were in normal range. In individual patients with PD and PSP (50% and 18%, respectively) delayed R2 latencies were recorded.

The most frequently abnormal blink reflexes, comparing the MSA, PSP and PD groups, were present in PD patients. We postulate that this may be explained by pathological influence of nigrostriatal pathway on the circuit linking the basal ganglia, cerebellum and brainstem.