An initial Medline search for articles on the Multiple Sleep Latency Test (MSLT) and Maintenance of Wakefulness Test (MWT) was performed on January 7, 2000. The following string of search terms was used: Multiple Sleep Latency Test or MSLT or Maintenance of Wakefulness or MWT or hypersomnia or hypersomnolence or daytime alertness, daytime sleepiness or daytime wakefulness or daytime somnolence. The search was limited to human research and only to articles published in English, French, or Japanese. This generated a total of 3,162 references. There were 2,864 in English, 199 in French, and 99 in Japanese. Similar searches on Psych Lit and Carl UnCover databases revealed no additional articles. An initial screening excluded the following: publications prior to 1976, articles in non-peer reviewed journals, and book chapters. This resulted in 2,195 potentially relevant articles.
All articles were screened based on title and English language abstract, if provided, to select studies that employed the MSLT or MWT. The inclusion criteria were publication in peer-reviewed journal and use of the MSLT or MWT. The exclusion criteria included abstracts, reviews, theoretical papers, editorials, case studies, drug studies, and human leukocyte antigen (HLA) studies. Studies using narcolepsy patients who were required to have sleep-onset of rapid eye movement periods (SOREMPs) on a previous MSLT were also excluded. Studies where the results of the MSLT were not given were also excluded. This resulted in a total of 495 potentially relevant articles. A second screening of the titles and abstracts not selected was performed by two other reviewers and an additional 150 papers were added to the potentially relevant list of articles for a total of 645 (495+ 150) papers for subsequent review.
On October 18, 2000, an additional Medline search was done to update the initial one using the same terms and conditions for the time period 1999-2000. This resulted in an additional 122 new citations. Review of these titles and abstracts, using the same inclusion and exclusion criteria as above, resulted in an additional 28 potentially relevant articles for a total of 673 (645+28). "Pearling," the process of manually scanning bibliography lists from manuscripts captured on the searches for additional relevant references not detected by Medline, netted an additional 15 citations. This resulted in a total of 688 (673+15) references.
On August 28, 2002, another Medline search was performed using the same terms and conditions for the time period 2000-2002. This resulted in 434 citations being identified. Using the same exclusion-inclusion criteria, 34 potentially relevant articles were identified for a total of (688 + 34) 722 references.
On October 9, 2003, a final Medline search was performed using the same terms and conditions for the time period 2002-2003. This resulted in 56 citations being identified. Using the same exclusion-inclusion criteria, 56 potentially relevant articles were identified for a total of (722+56) 778 references.
The titles and abstracts of the 778 papers were each screened by two reviewers to select those with adequately described data relevant to one of eight topics. Two topics were randomly assigned to each reviewer. Inclusion criteria were study appropriate to topic, test means, and standard deviations (SD) or standard error of the means (SEM) provided. Exclusion criteria included non-standard test procedure. If there was not enough information in the title and abstract to make a determination, the article was obtained and examined in more detail to determine acceptability. The topics and numbers of references (in parentheses) identified in each group for further review included:
- Number of sleep-onset of rapid eye movement periods in narcolepsy (28)
- Sleep latency mean on MSLT in narcolepsy (40)
- Sleep latency mean on MSLT or MWT in idiopathic hypersomnia (13)
- Sleep latency mean on MSLT or MWT pre- and post-treatment of obstructive sleep apnea (OSA), periodic limb movement disorder (PLMD), insomnia and restless legs syndrome (RLS) (106)
- Sleep latency mean on MSLT or MWT in medical and neurological conditions (45)
- Sleep latency mean on MSLT or MWT on safety (33)
- MSLT or MWT in pre- and post-drug treatment (74)
The pre- and post-drug treatment topic was added after all articles had been screened to exclude drug studies, so all 2,195 citations were again screened for this topic. Normative data was not pre-selected but obtained from other articles when found.