A 37-year-old man presented with right eyelid ptosis, which disappeared when the patient opened his mouth and reappeared when he closed his mouth. Synkinetic activation of the left orbicularis oculi muscle when attempting to voluntarily open the right eyelid was also present. Symptoms had been present since birth. The subject's family history revealed that both his father and two paternal uncles were affected by the same disorder.
The neurological examination disclosed no further abnormality while the ophthalmological examination revealed eterophory at distance and vertical strabismus. Electromyography (EMG) recordings from the facial muscles were normal, as were the brainstem auditory evoked potentials.
The control group for the neuroradiological examinations comprised 29 age- and sex-matched healthy subjects (41+-5.6 years). Twenty out of the 29 healthy volunteers were also involved in the neurophysiological investigations (age: 37+-5.0 years). Both the MGJWS patient and the healthy subjects gave their written informed consent to the experimental procedures, which were approved by the Ethics Committee of University of Rome "Sapienza" and conducted in accordance with the Declaration of Helsinki.
The kinematics of the eyelid and jaw movement was recorded using a 3D optoelectronic motion system (SMART motion system, BTS, Milan, Italy). The displacement of the reflective marker taped on the centre of the lower margin of the upper eyelid and on the mental prominence of the jaw in three-dimensional space was reconstructed off-line by a dedicated software (SMART Analyzer, BTS, Milan, Italy). Onset, offset, duration, peak velocity and amplitude were automatically computed for each downward and upward eyelid and jaw movement. Differences between the onset of eyelid and jaw movement were calculated. The Paired-sample T test was used to compare the onset of the upper eyelid and jaw movements during jaw opening and closing. Pearson's correlation coefficient was used to analyse movement duration of eyelid and jaw opening and closing movements.
The blink reflex, the masseter inhibitory reflex and the blink reflex recovery cycle were performed according to previously described techniques. The blink reflex recovery cycle was studied by delivering paired electrical shocks to the supraorbital nerve at interstimulus intervals (ISI) of 250 and 500 ms. The R2 recovery index was also calculated.
All the subjects underwent an MR imaging examination on a 3T scanner system (Intera Achieva, Philips Medical Systems, Best, The Netherlands). Diffusion-weighted images were corrected for head motion and eddy current distortions using FDT (FMRIB's Diffusion Toolbox 2.0), after which brain tissue was segmented using BET. Tensor fitting employed a constrained non-linear least squares procedure (CAMINO), followed by Fractional Anisotropy (FA) map estimation. Voxelwise statistical analysis of the data was carried out using Tract-Based Spatial Statistics (TBSS). TBSS projects all the subjects' FA data onto a mean FA tract skeleton, before applying voxelwise cross-subject statistics. The latter included full correction for multiple comparisons over space using permutation-based non-parametric inference (50,000 permutations). P-values were calculated and corrected for multiple comparisons using the "2D" parameter settings with threshold-free cluster enhancement.