Effect of Manual Editing of Total Recording Time: Implications for Home Sleep Apnea Testing

Study objectives: Type 3 home sleep apnea tests may underestimate the apnea-hypopnea index (AHI) due to overestimation of total sleep time (TST). We aimed to evaluate the effect of manual editing of the total recording time (TRT) on the TST and AHI.

Methods: Thirty 15-channel in-home polysomnography studies (AHI 0 to 30 events/h) scored using American Academy of Sleep Medicine criteria were rescored by two blinded polysomnologists after data from electroencephalogram, electrooculogram, and electromyogram were masked. In method 1, periods of probable wakefulness and artifact were manually edited and removed from analysis. Method 2 identified TST as the TRT without manual editing. Paired t-tests were used to compare the TST and AHI between these methods. Sensitivity and specificity of each method were calculated for gold standard AHI cutoffs of ≥ 5 and ≥ 15 events/h.

Results: TST (mean [standard deviation, SD]) by polysomnography, method 1, and method 2 was 366.0 (70.1), 447.1 (59.0), and 542 (61.9) min, respectively. The corresponding AHI was 12.5 (8.2), 10.8 (7.0), and 9.1 (6.1) events/h, respectively. Compared to polysomnography, both alternative methods overestimated the TST (method 1: mean difference [SD] 81.1 [56.1] min, method 2: 176.0 [89.7] min; both p < 0.001) and underestimated the AHI (method 1: mean difference [SD] -1.6 [3.3], method 2: -3.3 [3.9]; both p < 0.001). The sensitivity was 100% and 70.0% for method 1, and 91.3% and 40.0% for method 2 for identifying sleep-disordered breathing using AHI cutoffs of ≥ 5 and ≥ 15 events/h, respectively.

Conclusions: Manual editing of TRT reduces the overestimation of TST and improves the sensitivity for identifying studies with sleep-disordered breathing.

Commentary: A commentary on this article appears in this issue on page 9.