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

Background: 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.
Aims: To investigate the difference in the reorganization developing after facial nerve damage between patients who developed PFP at childhood-youth and middle-old age.
Patients and methods: 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, R₂ area, and recovery of the R₂ area of the blink reflex were investigated.
Statistical analysis : anova and Bonferroni tests were used.
Results: The R₂ 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.
Conclusion : Young age-at-onset of PFP is associated with more prominent excitability changes developing at the neuronal and interneuronal level.