The influence of age in peripheral facial palsy on brainstem reflex excitability

Neuronal plasticity is expected to be different at different ages and adaptive changes developing after peripheral facial palsy (PFP) may provide a clue in this respect.

To investigate the difference in the reorganization developing after facial nerve damage between patients who developed PFP at childhood-youth and middle-old age.

Twenty-two patients were divided into two groups according to the age-at-onset of PFP; young (PFP 1), and elderly (PFP 2). Two age-matched control groups (C 1 and C 2) comprised of 32 healthy subjects were included in the study. The latency, R(2) area, and recovery of the R(2) area of the blink reflex were investigated.

ANOVA and Bonferroni tests were used.

The R(2) areas were significantly greater on the intact side of the PFP 1 group as compared to that in the control group ( P =0.012). The recovery of R2 component was significantly enhanced on the symptomatic (P = 0.027), and intact (P = 0.041) sides in PFP 1 as compared to that in the C 2 group at the stimulus interval of 600 ms. Significant enhanced recovery was noted at 200 ms stimulus interval on the symptomatic side of the two PFP groups (PFP 1, P = 0.05 and PFP 2, P = 0.025) and on the intact side of the PFP 1 group (P =0.035) as compared to that in the control groups.

Young age-at-onset of PFP is associated with more prominent excitability changes developing at the neuronal and interneuronal level.