Are polysomnographic measures of sleep correlated to alexithymia? A study on laboratory-adapted sleepers

Since recent findings have pointed to a correlation between alexithymia and measures of poor sleep quality during the first night of adaptation to a sleep laboratory, the aim of the current study was to assess the same relation in healthy laboratory-adapted sleepers. As a further measure of rapid eye movement (REM) sleep characteristics, REM density was also measured.

Twenty-seven male subjects, without sleep or psychiatric disorders, filled out the 20-item Toronto Alexithymia Scale (TAS-20) and slept for two consecutive undisturbed nights. Polysomnography and REM density were measured in the postadaptation night.

Alexithymia scores did not correlate significantly with any polysomnographic variable or with REM density. Only the Externally Oriented Thinking (EOT) subscale showed a negative association with REM latency. Multiple regression on selected sleep measures as predictors confirmed these results.

Results do not extend to normal sleep the association previously found between alexithymia and a poor quality of sleep during the adaptation night in the sleep laboratory. The only polysomnographic measure showing an association, albeit little, with one facet of alexithymia was REM latency.