Abstract:

Objective To detect risk factors of silent aspiration in patients with amyotrophic lateral sclerosis (ALS) and the diagnostic value of ALSFRS-R scale. Methods A total of 68 patients with ALS were recruited in our study. According to the results of Videofluoroscopic Swallowing Study (VFSS), patients were divided into the silent aspiration group (9 cases) and the non-silent aspiration group (59 cases). The muscle strength of neck and limb was assessed using the Medical Research Council score (MRC) scale, and the independent influencing factors of silent aspiration were assessed using Logistic regression analysis. Receiver operating characteristic (ROC) curve was used to analyze the diagnostic value of ALSFRS-R bulbar subscales and swallowing items for silent aspiration. Results The results of univariate analysis showed that compared with the non-silent aspiration group, cervical flexor muscle strength and right proximal upper limb muscle strength were decreased in the silent aspiration group (P<0.05), and the proportion of patients with bulbar onset was higher in the silent aspiration group (P<0.05). Multivariate Logistic regression analysis showed that patients with limb onset were less likely to have occult aspiration than those of bulbar onset (OR=0.001, 95%CI: 0.000-0.222, P=0.014). The higher the cervical flexor muscle strength was, the less the risk of occult aspiration was (OR=0.089, 95%CI: 0.010-0.814, P=0.032). The results of ROC curve showed that the ALSFRS-R bulbar subscales and swallowing items had limit clinical diagnostic value for ALS patients with silent aspiration, and the areas under the curve (AUC) were 0.774 (95%CI：0.741-0.924) and 0.781 (95%CI： 0.757-0.934), respectively (P<0.05). When the Youden index was the maximum, the optimal cut-off value of ALSFRS-R bulbar subscales was 11, and the sensitivity and specificity for the diagnosis of silent aspiration were 88.89% and 57.63%, respectively. The optimal cut-off value of ALSFRS-R swallowing items was 3, and the sensitivity and specificity for the diagnosis of silent aspiration were 77.78% and 67.80%, respectively. Conclusion For ALS patients with bulbar onset and poor cervical flexor muscle strength, attention should be paid to the screening of dysphagia and early clinical intervention. ALSFRS-R bulbar subscales and swallowing items have limited diagnostic value for silent aspiration, and new scales need to be developed to assess the risk of silent aspiration in ALS patients.

Key words: amyotrophic lateral sclerosis, silent aspiration, cervical flexor muscle, ALSFRS-R