Diagnostic performance of single airflow channel recording (ApneaLink) in home diagnosis of sleep apnea.

BACKGROUND: ApneaLink is a novel single-channel screening device for sleep apnea detection which is based on pressure-transduced measurement of oronasal airflow, summarised as respiratory disturbance index per hour of recording time (RDI(ApneaLink)). We tested ApneaLink's diagnostic performance in a patient population with high prevalence of sleep apnea.

METHODS: ApneaLink was applied simultaneously with in-laboratory polysomnography (PSG) (n = 102, 24 female, age 54.7 years) and sequentially with PSG in the unattended home setting (n = 131, 37 female, age 59.1 years). Predictive values were computed for apnea-defining thresholds of apnea-hypopnea index (AHI) >or= 5/h, >or=10/h, >or=15/h. Night-to-night variability (NNV) was assessed over three consecutive nights (n = 55, 10 female, age 48.9 years).

RESULTS: RDI(ApneaLink) correlated well with apnea-hypopnea index on PSG (PSG(AHI)) on simultaneous (r = 0.98, bias -0.7) and unattended home application (r = 0.95, bias -0.6). Predictive values were highest at AHI >or= 10/h (in-laboratory: sensitivity 91.1%, specificity 87.5%, LR+ (positive likelihood ratio) 7.4, LR- 0.1; home: sensitivity 80%, specificity 85.5%, LR+5.5, LR- 0.2). NNV was low (V = 0.58 +/- 0.44, range 0-1.69).

CONCLUSION: ApneaLink is an accurate screening tool for sleep apnea in a population with high prevalence of the disorder.