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

Abstract

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. We therefore 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 vs. 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 to 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

Diagnostic utility of the amyotrophic lateral sclerosis Functional Rating Scale—Revised to detect pharyngeal dysphagia in individuals with amyotrophic lateral sclerosis

“…While this work represents the first attempt to examine the discriminant ability and clinical utility of the ALSFRS-R for detecting radiographically confirmed dysphagia, limitations need to be acknowledged. First, following typical analytic methods used in dysphagia research [ 30 , 31 ], the worst PAS score was utilized to determine swallowing safety status, which may have skewed outcomes towards impairment [ 26 ]. Given that we were interested in catching early impairment however, we feel that any potential bias was warranted.…”

“…However, the discriminant ability of the EAT-10 to detect global pharyngeal dysphagia in ALS, has not yet been established. In addition to PROMs, voluntary cough function is noted to significantly differ in individuals with ALS compared to healthy age and gender matched controls, contributing to the impaired ability to effectively expel tracheal aspirate and manage secretions in this population [26]. Given that peak expiratory flow is noted to be reduced by 50% in ALS patients with unsafe swallowing [27], voluntary cough peak expiratory flow (commonly known as peak cough flow testing) has been suggested as a screen to index one's physiologic airway defense capacity [28,29].…”

“…to be acknowledged. First, following typical analytic methods used in dysphagia research [30,31], the worst PAS score was utilized to determine swallowing safety status, which may have skewed outcomes towards impairment [26]. Given that we were interested in catching early impairment however, we feel that any potential bias was warranted.…”

Management of Dysphagia in Acquired and Progressive Neurologic Conditions

“…Collectively, much of the research relating to cough and swallow has shown that single hard cough airflow rates less than approximately 4.5 to 6 L/s (270-360 L/min) are associated with reduced swallow safety and dysphagia. [5][6][7] The research on sequential cough is less robust; however, Hegland and colleagues showed that, in PD, people without penetration or aspiration during swallowing had a more organized cough in terms of peak airflows and durations compared with those who did exhibit penetration or aspiration during swallowing. 8 While the measurement of peak cough airflow for a single There is a growing body of literature examining the use of reflexive, or induced, cough to identify the presence of penetration, aspiration, and swallowing dysfunction.…”

Differences in voluntary and reflexive cough strength in individuals with amyotrophic lateral sclerosis and healthy adults

“…Voluntary cough motor function can be objectively assessed using a peak flow meter, lending insight into the severity of dystussia 5 and the physiological capacity to cough and protect the airway. Compared with healthy matched controls, voluntary cough strength is noted to be reduced by 36% in individuals with ALS, 4 and those with a cough volume acceleration of less than 45.2 L/s/s were noted to be 5.6‐fold more to likely to penetrate or aspirate during swallowing 2 …”