Influence of age and gender on the jaw-stretch and blink reflexes

Abstract

The aim of this study is to investigate the influence of age and gender on jaw-stretch and blink reflexes (BR). Thirty "young" (26.5+/-0.7 years) and thirty "old" (47.8+/-1.8 years) healthy adults were included. Short-latency stretch reflex responses were evoked in the masseter and temporalis muscles by fast jaw-stretches, and BR in orbicularis oculi muscle were evoked by painful electrical pulses (0.5 ms duration), delivered by a concentric electrode placed on the left lower forehead close to the supraorbital foramen. For the jaw-stretch reflex, the pre-stimulus EMG activity in the old subjects was significantly lower than that of the young subjects in the right and left masseter and temporalis muscles (P<0.006), whereas there was no difference in the results between males and females. The normalized peak-to-peak amplitude of the EMG in the left masseter and left and right temporalis muscles was significantly lower in the old subjects compared with the young subjects (P<0.02). Females had significantly higher normalized peak-to-peak EMG amplitudes compared with males in the right masseter and left temporalis muscles (P<0.05). The old subjects had significantly lower root mean square (RMS) (P=0.01) and average (P<0.02) BR values in the right and left orbicularis oculi muscles, and lower area under the curve (AUC) (P=0.02) values in the left orbicularis oculi muscle compared with the young subjects. Female subjects had significantly lower AUC (P=0.02) in the left orbicularis oculi muscle compared with males. The old subjects had significantly later offset (P<0.003) and longer duration (P<0.001) in the left orbicularis oculi compared with the young subjects. The results of the present study demonstrated a significant effect of both age and gender on stretch and BR and suggested that these variables should be taken into consideration in the interpretation of brainstem reflexes in basic and clinical studies.

The effect of sex and chronic low back pain on back muscle reflex responses

“…In the present study, even though we attempted to solve this problem, Ang150ms was still signiWcantly higher in women but, fortunately, not to the extent to inXuence the reXex responses according to the ANCOVA results. The literature on this topic is mixed, showing shorter latencies and higher amplitudes in women for the jaw muscles (Peddireddy et al 2006;van Selms et al 2005), while no sex eVect was found for the triceps surae (Blackburn et al 2008) and quadriceps (Moore et al 2002). The available literature does not support an explanation based on diVerences in spinal stiVness.…”

Fiber type and myosin heavy chain compositions of adult pretarsal orbicularis oculi muscle

“…Although MyHC IIX content appeared to increase with aging in the linear regression plot, the P value was not significant. Previous studies have demonstrated an age-related reduction in amplitude and peak velocity of spontaneous and voluntary blinks (Peddireddy et al 2006;Wouters et al 2001). Therefore, reduction of the IIA fiber area and the relative MyHC IIA composition in human POOM may play a role in the decrease of the muscle contraction speed during aging.…”

Diet‐induced obesity decreases rate‐dependent depression in the Hoffmann’s reflex in adult mice

“…Similarly, few studies have reported muscle stretch reflex sex differences. However, a study of human jaw muscle stretch reflexes showed greater reflex amplitude in females than in males (Peddireddy et al ), while a study of back reflexes showed larger reflex amplitudes in males (Larivière et al ). Further studies are needed to better understand whether there are consistent sex differences in H‐reflex and/or stretch reflex amplitudes and the physiological relevance of those differences.…”