Central Facial Palsy - Studies

Studies

In one study, the lab group primarily focused on the electrophysiological evaluation of corticonuclear descending fibers to the lower facial motor neurons in patients with central facial palsy, and the discussion of how central facial palsy can become mild from various recovery techniques. It was found that in normal subjects unilateral TMS stimulation of the motor cortex induced EMG responses from the perioral muscles. This finding supports other studies in favor that bilateral projection of the corticonuclear fibers of the lower facial muscles are present in humans and primates with normal function. The study also found that ipsilateral corticonuclear fibers were found in the lower facial muscles, which does not coincide with other papers. The variation could be from the selection of muscles used in the study as well as the different electrodes that were used.

The orbicularis oculi muscles are often examined in patients with facial paralysis. In the study, it was difficult to illicit any corticunuclear EMG responses from this area in both normal subjects and in patients with CFP . This could be because the cortical links and synapses of the upper facial muscles are limited in function and TMS could not presynaptically stimulate the correct areas observed in paralysis. These areas are important because they will stimulate the presynaptic preterminals in cortical neurons. Also, this stimulation to the brain can not be studied on healthy human subjects. The upper facial muscle ME responses could not be innervated by TMS and the low threshold of blink reflexes often interferes with the nature of corticobulbar influences.