A novel quality assurance program for multiple sleep latency tests.

The Multiple Sleep Latency Test (MSLT) is the internationally recognized gold standard method for objectively measuring sleepiness. MSLT results are ultimately expressed in terms of the overall Mean Sleep Latency (MSL) and the total number of Sleep Onset REM Periods (SOREMPs). Based on these measures, the International Classification of Sleep Disorders (ICSD) has developed firm diagnostic criteria by which Narcolepsy is defined by a MSL <= 8 min with <= 2 SOREMPs, while Idiopathic Hypersomnia is defined by a MSL <= 8 min with <= 1 SOREMP. Once diagnosed, the wakefulness-promoting agent Modafinil is recommended for the treatment of the daytime sleepiness associated with these conditions. In Australia, Modafinil is expensive and its long-term use can create significant financial stress for many patients. Fortunately, the Pharmaceutical Benefits Scheme offers subsidised Modafinil for patients who return a MSL <= 10 min. MSLT results can thus have a significant impact on patients' lives in terms of both disease diagnosis and treatment. Recognising this fact, our lab has recently come to appreciate the fact that MSLT analysis is subject to the same subjective interpretation and inter-scorer reliability issues as standard polysomnography. In response, we have developed a quality assurance program that seeks to safeguard the integrity of our MSLTs. In accordance with this program, our MSLTs are initially analysed by the scientist who conducts the MSLT. The lab Quality Manager then creates a new score-data record and assigns the record to a second scientist, who rescores it without reference to the original analysis. The Quality Manager then records and compares the results to determine if there is a significant difference between the analyses in terms of MSLs and SOREMP counts. A significant difference is MSLs is defined as a difference of <= 1 min., or a difference that would result in a change in diagnosis based on the 8-minute ICSD threshold or a change in Modafinil ava