The study of split-face phenomenon in patients with bulbar-involved amyotrophic lateral sclerosis
10.3760/cma.j.cn113694-20240609-00396
- VernacularTitle:颅段受累肌萎缩侧索硬化患者分裂脸现象研究
- Author:
Yu WANG
1
;
Li TIAN
1
;
Ju ZHU
1
;
Xiaohui SUN
1
;
Yanping REN
1
;
Zhecheng ZHANG
1
Author Information
1. 天津市第三中心医院神经内科，天津 300170
- Publication Type:Journal Article
- Keywords:
Amyotrophic lateral sclerosis;
Compound muscle action potential amplitude ratio;
Split-face phenomenon
- From:
Chinese Journal of Neurology
2025;58(2):130-137
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To explore the split-face phenomenon in patients with bulbar-involved amyotrophic lateral sclerosis (ALS) through clinical and electrophysiological studies.Methods:A total of 52 clinically definite and clinically probable cases of bulbar-involved ALS, diagnosed according to the World Federation of Neurology El Escorial criteria, were retrospectively collected in the Third Central Hospital of Tianjin from September 2019 to November 2022. And 58 patients with idiopathic facial nerve paralysis with onset time≤7 days who visited the Department of Neurology of the Third Central Hospital of Tianjin during the same period were collected as control group. The firm eye closure (FC) score and cheek bulge (CB) score were used to assess the clinical involvement of facial muscles (dividing into facial muscle involvement group and non-facial muscle involvement group) and the presence of the split-face phenomenon (strong eye closure and weak cheek bulging) in ALS patients. The compound muscle action potential (CMAP) amplitudes of the bilateral orbicularis oculi and orbicularis oris muscles were measured using the Nicolet EDX Viking electromyography/evoked potential system. The CMAP amplitude ratio was calculated. The facial nerve electrophysiological differences were compared between ALS patients with bulbar involvement and patients with idiopathic facial nerve paralysis. The analysis of electrophysiological data across various groups was carried out utilizing the Kruskal-Wallis H test, while pairwise comparisons between groups were executed employing the Bonferroni correction method. Additionally, a stepwise binary Logistic regression analysis was implemented to ascertain the factors associated with facial muscle involvement in patients with bulbar-involved ALS. The receiver operating characteristic (ROC) curve was used to assess the diagnostic accuracy of facial nerve electrophysiological testing in diagnosing ALS in the presence of symptoms of facial muscle involvement. Results:Among the 52 ALS patients with bulbar involvement, there were 20 cases (38.5%) with facial muscle involvements, all of which were bilateral; 16 patients (30.8%) exhibited weakness solely in the ability to puff their cheeks, 1 patient (1.9%) presented with weakness exclusively in closing the eyes, and 3 patients (5.8%) experienced weakness in both closing the eyes and puffing the cheeks. The Revised Amyotrophic Lateral Sclerosis Functional Rating Scale (ALSFRS-R) score of the facial muscle involvement group was lower compared to the non-facial muscle involvement group (36.90±9.20 vs 40.75±5.21, t=2.419, P=0.019), while the FC score and CB score were higher in the facial muscle involvement group [FC score: 0(0, 1) vs 0(0, 0), U=5.854, P<0.001; CB score: 4(3, 4) vs 0(0, 0), U=9.069, P<0.001], showing statistically significant differences. There was no statistically significant difference in the CMAP amplitude of the orbicularis oculi muscle between the facial muscle involvement group and the healthy side of the idiopathic facial nerve paralysis group, the affected side of the idiopathic facial nerve paralysis group, and the non-facial muscle involvement group (all P>0.05). The CMAP amplitude of the orbicularis oris muscle in the facial muscle involvement group [1 100.00 (775.00, 1 375.00) μV] was lower than that in the healthy side of the idiopathic facial nerve paralysis group [1 800.00 (1 400.00, 2 300.00) μV] and the non-facial muscle involvement group [1 555.00 (1 202.50, 1 980.00) μV], with statistically significant differences ( H=5.884, P<0.001; H=4.114, P<0.001). There was no statistically significant difference in the CMAP amplitude of the orbicularis oris muscle between the facial muscle involvement group and the affected side of the idiopathic facial nerve paralysis group ( P>0.05). The CMAP amplitude ratio of the orbicularis oculi/orbicularis oris muscles in the facial muscle involvement group [0.83(0.51, 1.14)] was higher than that in the healthy side of the idiopathic facial nerve paralysis group [0.55(0.39, 0.73)], the affected side of the idiopathic facial nerve paralysis group [0.57(0.40, 0.73)], and the non-facial muscle involvement group [0.60(0.42, 0.71)], with statistically significant differences ( H=-3.440, P=0.003; H=-3.433, P=0.004; H=-3.225, P=0.008). Logistic regression analysis revealed that the CMAP amplitude of orbicularis oris muscle ( OR=0.998,95% CI 0.997-0.999, P<0.001) and ALSFRS-R score ( OR=0.916,95% CI 0.857-0.979, P=0.010) were factors associated with facial muscle involvement in ALS patients with bulbar involvement. The ROC curve analysis results showed that the area under the curve (AUC) of the orbicularis oculi muscle CMAP was 0.629, the AUC of the orbicularis oris muscle CMAP was 0.838, and the AUC of the CMAP amplitude ratio of the orbicularis oculi/orbicularis oris muscles was 0.690 in the facial muscle involvement group. Conclusions:Patients with bulbar-involved ALS have split-face phenomenon characterized by strong eye closure and weak cheek bulging. When bulbar-involved ALS patients have symptoms of facial muscle involvement, the CMAP amplitude of the orbicularis oris muscle decreases significantly, whereas the CMAP amplitude of the orbicularis oculi muscle remains relatively stable, further illustrating the split phenomenon.
