Allega OR, et al. – This investigation was planned to perform an Item Response Theory (IRT) analysis of the Biological Rhythms Interview for Assessment in Neuropsychiatry (BRIAN) and examine its relationships with objective sleep and rhythm disturbance measures. The authors concluded that the BRIAN displays promising external validity compared to objective parameters of circadian rhythmicity.

Methods

• For the purpose of this study, one hundred three subjects (31 bipolar, 32 major depression and 40 healthy volunteers) wore an actiwatch for 15 days, and completed a first morning urine sample and the BRIAN on day 15.
• After that, IRT analysis evaluated individual BRIAN items and their relationship to total score.
• Individual actiwatch records were processed to produce a sequence of transitions between rest/activity, and a likelihood of transitioning between states was calculated to examine sleep-wake dynamics.
• Cosinor analysis produced daily activity rhythms (DARs).
• Finally, Spearman correlations were utilized to evaluate the relationship between sleep/DAR variables and the BRIAN.

Results

• According to the findings obtained, IRT analyses demonstrated that 11 of 18 BRIAN items showed a high level of discrimination between item options across a range of BRIAN total scores.
• It was noted that total BRIAN score associated with wake after sleep onset, total activity count during sleep, and urinary 6-sulphatoxymelatonin.
• Findings revealed that BRIAN Activity domain associated with the daytime transition probability from rest to activity.