Dysphagia in amyotrophic lateral sclerosis: Quantification of bulbar motor dysfunction

Risdiplam improves subjective swallowing quality in non-ambulatory adult patients with 5q-spinal muscular atrophy despite advanced motor impairment

BACKGROUND

5q-associated spinal muscular atrophy (SMA) is characterized by the progressive loss of motor neurons with consecutive weakness and atrophy of the limb, respiratory, and bulbar muscles. While trunk and limb motor function improve or stabilize in adults with SMA under nusinersen and risdiplam treatment, the efficacy on bulbar function in this age group of patients remains uncertain. However, it is important to assess bulbar dysfunction, which frequently occurs in the disease course and is associated with increased morbidity and mortality.

METHODS

Bulbar function was evaluated prospectively in 25 non-ambulatory adults with type 2 and 3 SMA before and 4 and 12 months after risdiplam treatment initiation using the Sydney Swallow Questionnaire (SSQ) and the bulbar subscore of the Amyotrophic Lateral Sclerosis Functional Rating Scale Revised (b-ALSFRS-R). Extremity function was assessed using the Hammersmith Functional Motor Scale Expanded (HFMSE) and Revised Upper Limb Module (RULM).

RESULTS

Subjective swallowing quality, measured with the SSQ, improved after 12 months of therapy with risdiplam. For the b-ALSFRS-R, a non-significant trend towards improvement was observed. The RULM score improved after 12 months of risdiplam therapy, but not the HFMSE score. HFMSE and RULM scores did not correlate with the SSQ but the b-ALSFRS-R score at baseline.

CONCLUSIONS

The improvement in subjective swallowing quality under risdiplam treatment, despite an advanced disease stage with severe motor deficits, strengthens the importance of a standardized bulbar assessment in addition to established motor scores. This may reveal relevant treatment effects and help individualize treatment decisions in the future.

Diagnostic utility of different dysphagia screening tools to detect dysphagia in individuals with amyotrophic lateral sclerosis

OBJECTIVE

Dysphagia is a common and serious clinical symptom of amyotrophic lateral sclerosis (ALS). The study aimed to evaluate the diagnostic utility of four dysphagia screening tools in ALS, including the ALS Functional Rating Scale-Revised (ALSFRS-R) bulbar subscale, water-swallowing test (WST), Eating Assessment Tool-10 (EAT-10) and Sydney Swallow Questionnaire (SSQ).

METHODS

A total of 68 individuals from First Hospital, Shanxi medical university, were recruited in the study. The ALSFRS-R, WST, EAT-10, SSQ and the gold standard video fluoroscopic swallowing study (VFSS) were performed. The Penetration Aspiration Scale (PAS) during VFSS was assessed to identify unsafe swallowing (PAS ≥ 3) and aspiration (PAS ≥ 6). Receiver operator characteristic curve (ROC) analyses were performed to evaluate the accuracy of the 4 tools. Youden index was used to determine the ideal cut-off value for each tool.

RESULTS

Of the patients, 20.59% (14/68) presented unsafety swallowing and 16.18% (11/68) had aspiration. The four tools could effectively identify patients with unsafe swallowing and aspiration. The EAT-10 had the maximum AUC (0.873 and 0.963, respectively) among the tools in the diagnosis of unsafe swallowing and aspiration. To detect unsafe swallowing and aspiration, an EAT-10 score of 6 (sensitivity: 78.6%, specificity: 87.0%) and an EAT-10 score of 8 (sensitivity: 90.9%, specificity: 91.2%), were the most appropriate cut-off points, respectively.

CONCLUSIONS

The ALSFRS-R bulbar subscale, WST, EAT-10, and SSQ could effectively identify unsafe swallowing and aspiration in patients with ALS. Of the four tools, the EAT-10 was relatively accurate, safe, and convenient. Further studies including more patients should be conducted to verify the conclusions.

Comparison of Slow and Forced Vital Capacity on Ability to Evaluate Respiratory Function in Bulbar-Involved Amyotrophic Lateral Sclerosis

Background and Objective

The percent-predicted forced vital capacity (FVC%) in the pulmonary function test (PFT) is generally used to evaluate the respiratory function in amyotrophic lateral sclerosis (ALS). The slow vital capacity (SVC) is another method to evaluate the respiratory function. Some neurologists found that the FVC% was not reflective of respiratory symptoms and the percent-predicted SVC (SVC%) was found to be higher in some patients with bulbar-onset ALS. We aimed to compare the percent predicted SVC (SVC%) with FVC% in evaluating the respiratory function and investigate the associations between the associations between clinical characteristics and the difference between the SVC% and the FVC% (SVC%-FVC%) in bulbar-involved ALS patients.

Method

This prospective study included patients with bulbar-involved ALS who visited the Peking University Third Hospital between October 2020 and November 2021. They underwent comprehensive clinical assessments, including bulbar symptom assessments, revised ALS functional rating scale (ALSFRS-R), Rasch-Built Overall Amyotrophic Lateral Sclerosis Disability Scale (Roads), and PFTs. The group differences were analyzed using parametric and non-parametric tests.

Results

A total of 59 participants were initially enrolled, and 51 of them were included in the final analysis. In patients with bulbar-involved ALS, the SVC% (73.82 ± 21.95%) was significantly higher (p = 0.013) than the FVC% (71.42 ± 23.15%). After controlling for other relevant variables, a partial correlation analysis showed a significant correlation (r = −0.352, p = 0.041) between ALSFRS-R1 score and SVC%-FVC%.

Conclusion

Our prospective study found that the SVC% was significantly higher and more reflective of actual respiratory function than the FVC% in patients with bulbar-involved ALS. Furthermore, the severity of dysarthria was found to be positively correlated with SVC%-FVC%, providing a clinical marker for predicting SVC%-FVC%.