P237 Cough frequency in acute stroke: Abstract P237 Table 1

Abstract

Introduction and objectivesFew studies have investigated cough frequency in neurological patient groups, in which cough may be impaired or increased in the presence of aspiration. This study aimed to (1) validate the Leicester Cough Monitor (LCM) on a stroke unit, where background coughs might contaminate one patient’s cough recordings; and (2) observe cough frequency longitudinally in a convenience sample of acute stroke survivors.MethodsTo validate the LCM, 15-minute recordings were made from 5 patients on a stroke unit. LCM results were compared with real-time cough counts by a researcher present in the room (visual and auditory). To observe cough frequency longitudinally, 21 stroke survivors underwent 24-hour LCM recordings at baseline (<2 weeks post stroke), week 1 and 4. Participants (14 men, mean (SD) age 60 (15) years) had moderate stroke impairment (median (IQR) NIHSS score 8 (5, 11)) with cortical (n = 9), subcortical (n = 9), brainstem (n = 2) and cerebellar (n = 1) strokes. Five randomly selected recordings were analysed by a second researcher, blinded to subject characteristics and not present during the recordings.ResultsIn the validation study, the real-time observer counted 67 subject coughs plus 81 background coughs in total. The LCM returned a subject cough count of 68, not significantly different to the observer’s count (p = 0.99) with excellent agreement (ICC 0.996, 95% CI: 0.967, >0.999). Inter-rater reliability for LCM hourly cough counts was good (ICC 0.973, 95% CI: 0.789, 0.997). In the longitudinal cohort, average cough frequency was higher at baseline and reduced over time, with wide individual variability (Table 1) and higher cough frequency during day-time. There were no significant associations between cough frequency and sex, age, stroke site, stroke severity, swallowing safety, smoking status or ACE-inhibitor use.Abstract P237 Table 124-hour cough frequency (median, range) following acute stroke. Baseline assessments were conducted within 2 weeks of stroke24-hour cough frequencyBaseline(n = 21)Week 1(n = 20)Week 4(n = 17)Total number of coughs118 (4, 375)60 (6, 217)56 (1, 186)Hourly coughs5 (0, 16)2 (0, 9)2 (0, 8)Day time coughsa86 (4, 282)30 (6, 159)41 (1, 108)Hourly day time coughs6 (0, 20)2 (0, 11)3 (0, 8)Night time coughsa21 (0, 112)18 (0, 58)9 (0, 90)Hourly night time coughs2 (0,11)2 (0, 6)1 (0, 9) aday time: 08:00–22:00, night time: 22:00–08:00.ConclusionsThis study is limited due to the small sample size and should be regarded as exploratory. It was possible to validate the LCM for application on an acute stroke unit. The findings might serve hypothesis-generation: For example, is cough frequency after stroke increased, indicating sub-clinical levels of swallowing impairment and aspiration threat, which trigger frequent protective coughs?

Predictive Value of Cough Frequency in Addition to Aspiration Risk for Increased Risk of Pneumonia in Dysphagic Stroke Survivors: A Clinical Pilot Study

“…In their population, coughing and choking episodes were common but infrequently associated with overt chest infection. Kulnik et al, 2015, in their longitudinal one-month observational study, noted that average nocturnal cough frequency as measured with the Leicester Cough Monitor [36] in acute-stroke survivors was higher at baseline and reduced over time, with wide individual variability [25]. Their results support our suggestion that frequent protective coughs triggered in response to frequent aspiration events may constitute the underlying mechanism by which higher cough frequency indicates increased pneumonia risk.…”

“…In connection with dysphagia, most cough research has focused on assessing reflex cough sensitivity or volitional cough strength, but there has been very little research on the role of cough frequency in the context of post-stroke dysphagia [23]. Only very few studies have explored cough frequency in neurological patient groups [24,25]. The incidence of coughs can be measured either by patient selfreport, counting of cough episodes by an observer, or by portable cough monitors that are commercially available.…”