Agreement of different methods for assessing sleep characteristics: a comparison of two actigraphs, wrist and hip placement, and self-report with polysomnography.

Objective: To assess the agreement of sleep parameters measured by two actigraphs (SOMNOwatch plus, ActiGraph GT3X+) at two different placements (wrist, hip) and of self-reported sleep with polysomnography (PSG).

Methods: We estimated agreement with PSG for total sleep time (TST), sleep onset latency (SOL), wake after sleep onset (WASO), number of awakenings after sleep onset (NASO), and sleep efficiency (SE%) for 100 participants of the general population, aged 18-75 years by judging mean differences to PSG and intervals of agreement using Bland-Altman plots.

Results: Mean difference to PSG for TST was 8.

Establishing the bidirectional relationship between depression and subclinical arteriosclerosis--rationale, design, and characteristics of the BiDirect Study.

Background: Depression and cardiovascular diseases due to arteriosclerosis are both frequent and impairing conditions. Depression and (subclinical) arteriosclerosis appear to be related in a bidirectional way, and it is plausible to assume a partly joint causal relationship. However, the biological mechanisms and the behavioral pathways that lead from depression to arteriosclerosis and vice versa remain to be exactly determined.