Buccopalpebral reflex in Parkinson disease and blink reflex study

OBJECTIVE: To define a new primitive reflex named the buccopalpebral reflex (BPR), and to investigate this reflex clinically and neurophysiologically in patients with Parkinson disease.

METHODS: This prospectively designed study included 17 patients, 9 BPR positive patients, and 8 BPR negative patients in Ankara Research and Training Hospital, Ankara, Turkey, and was carried out between January and December 2008. All patients had Parkinson disease without any medication. Using the blink reflex technique, 3 branches of the trigeminal nerve were stimulated. Additionally, the Mini Mental State Examination (MMSE), the Unified Parkinson’s Disease Rating Scale (UPDRS), the Hoehn and Yahr Score (HYS), the blink frequency, and the duration of Parkinson disease was also matched between the 2 groups.

RESULTS: In patients with positive BPR, 5 had tremor and the remaining 4 had bradykinesia as a dominant symptom, while all other patients with negative BPR had only tremor. When blink reflex findings were compared between the 2 groups, R2 and contralateral R2 latencies that were taken by supraorbital stimulus were significantly shorter in the BPR positive patients. There were no statistically significant differences in terms of MMSE, UPDRS, HYS, and frequency of blinking, and duration of illness between the 2 groups.

CONCLUSION: This reflex may be an indicator of sensitivity or decrease of threshold level such as Myerson’s sign, in which there is no inhibition in glabella reflex. The blink reflex findings support this hypothesis.