Insomnia scale made available to Japanese patients
medwireNews: A Japanese version of the Athens Insomnia Scale (AIS-J) has been developed, giving researchers and clinicians a useful self-rating measure for diagnosing insomnia.
The AIS-J was found to have good internal consistency and was reliable in distinguishing patients with insomnia from those without the condition. It also showed a high correlation with alternative authorized scales for measuring insomnia symptoms.
“As the scale is both convenient to administer and has a high accuracy, the AIS-J can be expected to have high utility not only in epidemiological research but also for clinical evaluation,” say the study authors, led by Isa Okajima (Japan Somnology Center, Tokyo, Japan).
The team used a back-translation design to develop the AIS-J, which is based on the International Classification of Diseases-10 criteria. It has a two-factor structure, with items 1–5 determining the severity of nocturnal sleep problems, such as waking during the night, short sleep duration, and sleep quality, while items 6–8 measure daytime dysfunction, including daytime sleepiness.
Internal consistency was high, ranging from 0.78 to 0.88 for factors 1, 2, and the total score.
The AIS-J proved a valid measure, being significantly highly correlated with the Pittsburgh Sleep Quality Index and the Insomnia Severity Index.
The researchers also comment that, in diagnosing insomnia, the AIS-J not only differentiated patients with insomnia from those without the condition, but also those with primary insomnia from patients with depression or anxiety.
They calculate a cut-off AIS-J total score of 5.5 points for determining pathologic insomnia (primary or secondary) and 3.5 points when using just the five nocturnal items.
Therefore, according to the study, published in Psychiatry and Clinical Neurosciences, if a person scores 6 points or higher on the AIS-J, pathological insomnia can be diagnosed with a sensitivity of 92% and a specificity of 93%.
“These results suggest that the AIS-J has a high validity and that the scale is adequate for assessing insomnia symptoms,” say Okajima and colleagues.
They note, however, that they did not evaluate test–retest reliability and, as the study participants were all middle-aged, performance of the AIS-J in other age groups would need to be assessed.
Despite this, the team expects the scale “to be highly useful in a variety of clinical and research settings where there is a requirement for sleep problems to be quantified.”
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By Lucy Piper, Senior medwireNews Reporter