Interaction between alcohol consumption and use of peripheral arterial tone home sleep apnea tests for sleep apnea evaluation.

OBJECTIVE/BACKGROUND: Home sleep apnea tests utilizing peripheral arterial tone (PAT HSAT) detect sleep disordered breathing by measuring various physiologic measures including changes in arterial volume in the finger. Validation tests comparing PAT HSAT to simultaneous polysomnography (PSG) have demonstrated a high correlation. Alcohol increases peripheral vasodilation, which may alter arterial tone in the finger. Validation studies have not evaluated for an interaction between alcohol consumption and PAT HSAT measures. PATIENTS/METHODS: We describe an in-depth evaluation of a 53-year-old man who consumes alcohol on nightly basis. He underwent a series of 5 diagnostic studies under different conditions: three PAT HSATs (two nights with and another without alcohol) and two polysomnograms (one night with and another without alcohol). RESULTS: Obstructive sleep apnea (OSA) was found on both polysomnograms but only on the PAT HSAT without alcohol, raising the possibility of two false negative PAT HSAT results after alcohol consumption. CONCLUSIONS: This report demonstrates the need for further investigations into the performance of PAT HSATs with and without alcohol. In the meantime we recommend that testing be done without alcohol and over the course of multiple nights.

Fast and slow implementations of relaxed-clock methods show similar patterns of accuracy in estimating divergence times.

Phylogenetic analyses are using increasingly larger data sets for estimating divergence times. With this increase in data sizes, the computation time required is becoming a bottleneck in evolutionary investigations. Our recent study of two relaxed-clock programs (BEAST and MultiDivTime [MDT]) showed their usefulness in time estimation; however, they place a significant computational time burden on biologists even for moderately small data sets. Here, we report speed and accuracy of another relaxed-clock program (MCMCTree, MC2T). We find it to be much faster than both MDT and BEAST while producing comparable time estimates. These results will encourage the analysis of larger data sets as well as the evaluation of the robustness of estimated times to changes in the model of evolutionary rates and clock calibrations.