Characteristics of impaired voluntary cough function in individuals with amyotrophic lateral sclerosis.

OBJECTIVE: Although cough impairment (dystussia) is common in individuals with amyotrophic lateral sclerosis (ALS) and contributes to a reduced physiologic capacity to defend the airway, characteristics of dystussia have not yet been delineated. Therefore, we aimed to compare voluntary cough spirometry airflow patterns between individuals with ALS and healthy age and gender-matched controls. METHODS: Thirty-two individuals with a diagnosis of probable-definite ALS (El-Escorial Criterion) and 29 healthy age and gender-matched controls underwent voluntary cough spirometry testing. Two blinded raters derived six objective voluntary cough airflow measures including: peak inspiratory phase duration, peak inspiratory flow rate, compression phase duration, peak expiratory rise time, peak expiratory flow rate, and cough volume acceleration. Independent samples t-tests with Cohen's d effect sizes were performed between Healthy versus ALS groups for cough metrics (alpha =0.05). RESULTS: ALS individuals demonstrated prolonged inspiratory phase and expiratory phase rise time durations, reduced inspiratory and expiratory flow rates, and lower cough volume acceleration during voluntary cough production compared with healthy controls (p < 0.05). No differences in compression phase duration were observed (p > 0.05). CONCLUSIONS: This study compared characteristics of voluntary cough airflow patterns of individuals with ALS to healthy-matched controls. Findings identified impairments in both inspiratory and expiratory voluntary cough airflow, resulting in slower, weaker, and thus less effectiveness voluntary cough production in ALS individuals. These data afford insight into the impaired physiology underlying inadequate airway clearance and secretion management in individuals with ALS.

Combined respiratory training in an individual with C9orf72 amyotrophic lateral sclerosis.

This case study examined the impact of a respiratory strength training program targeting inspiratory and expiratory musculature in an individual with C9orf72 amyotrophic lateral sclerosis (ALS). The individual tolerated 24 months of respiratory training completed at home, 50 repetitions per day, and 5 days per week. Significant increases in maximum inspiratory pressure (from 71 to 134 centimeters of water), maximum expiratory pressure (from 108 to 197 centimeters of water) and peak cough flow (from 331 to 655 Liters per minute) were noted and forced vital capacity remained unchanged. A moderate intensity respiratory strength training program applied early in the disease progression improved function in this C9orf72 ALS individual.

Reduced pharyngeal constriction is associated with impaired swallowing efficiency in Amyotrophic Lateral Sclerosis (ALS).

BACKGROUND: Swallowing inefficiency is a prevalent but understudied problem in individuals with Amyotrophic Lateral Sclerosis (ALS). Although reduced pharyngeal constriction has been identified as a mechanism contributing to swallowing inefficiency following stroke, this relationship has not been empirically tested in the ALS population. This study sought to characterize profiles of swallowing efficiency in a sample of ALS patients and investigate relationships between pharyngeal constriction and swallowing efficiency. METHODS: Twenty-six adults with ALS underwent videofluoroscopic swallowing studies, involving 3 mL-thin, 20 mL-thin, and 3 mL-pudding boluses. Full-length recordings were segmented into bolus clips and randomized for analysis. We recorded the total number of swallows per bolus and obtained normalized pixel-based measures of pharyngeal constriction area and post-swallow residue in the vallecular and pyriform sinuses. Linear mixed models with Spearman's correlations were used to determine relationships between pharyngeal constriction and swallowing efficiency, with added factors of bolus volume and thickness. KEY RESULTS: Individuals with ALS demonstrated reduced pharyngeal constriction and increased vallecular and pyriform sinus residue, compared to norms. Reduced pharyngeal constriction had a significant effect on the presence of vallecular and pyriform sinus residue as well as the number of swallows per bolus. Increased bolus thickness was associated with increased vallecular residue, while increased bolus volume was associated with reduced pharyngeal constriction. Results were significant at P < 0.05. CONCLUSIONS & INFERENCES: Our results suggest that reduced pharyngeal constriction is a significant physiological parameter related to swallow inefficiency in ALS. Future work is needed to corroborate these preliminary results and investigate factors to mitigate such impairments.