Table 3.
Summary of clinical significance thresholds for critical and important outcome measures.
| Outcome Tool | Clinical Significance Threshold* | Desired Change |
|---|---|---|
| Accident risk | 10% | Decrease |
| Cataplexy | — | — |
| Diary-based daily/weekly episode frequency | 25% | Decrease |
| Severity | 25% | Decrease |
| Cognitive performance | — | — |
| Psychomotor vigilance test—reciprocal reaction time | 10% | Increase |
| Difficulty waking in the morning | — | — |
| Varies | 0.5 standardized mean difference | Decrease |
| Disease severity | — | — |
| CGI | 1-point OR | Decrease |
| 33% of patients reporting change | Improvement | |
| PGI | 1-point OR | Decrease |
| 33% of patients reporting change | Improvement | |
| Frequency and duration of symptoms | 10% | Decrease |
| Number of d incapacitated | 10% | Decrease |
| Other quantitative tools | 10% | Improvement |
| Other qualitative tools | 33% of patients reporting change | Improvement |
| Excessive daytime sleepiness | — | — |
| ESS | 2 points | Decrease |
| ESS-CHAD | 2 points | Decrease |
| MWT | 2 min | Increase |
| MSLT | 1 min | Increase |
| SSS | 1 point | Decrease |
| Fatigue | — | — |
| FSS (global change) | 0.5 points | Decrease |
| SF-36 energy/vitality subscale | 3 points | Increase |
| BFI | 0.3 points | Increase |
| FIS | 4.8 points | Increase |
| MAF (global change) | 5.0 points | Increase |
| Mood | — | — |
| BDI | 5 points | Decrease |
| CDI | 6 points | Decrease |
| PHQ-2 | 1 point | Decrease |
| PHQ-9 | 2 points | Decrease |
| Quality of life | — | — |
| FOSQ | 1 point | Increase |
| PedsQL | 1 point | Increase |
| SF-36 | — | — |
| (Physical Component Summary) | 3 points | Increase |
| (Mental Component Summary) | 3 points | Increase |
| SF-12 | 4 points | Increase |
| Sleep inertia | — | — |
| Varies | 0.5 standardized mean difference | Decrease |
| Sleep quality | — | — |
| PSQI | 3 points | Decrease |
| PSG/actigraphy-based sleep efficiency (%) | 10% | Increase |
| Work/school performance/attendance | — | — |
| Varies | 0.5 standardized mean difference | Increase |
*The clinical significance threshold applies to the comparison of posttreatment effects between intervention and placebo as well as a pre-/post treatment difference. BDI = Beck’s Depression Inventory, BFI = Brief Fatigue Inventory, CDI = Children’s Depression Inventory, CGI = Clinical Global Impression of change, ESS = Epworth Sleepiness Scale; ESS-CHAD = Epworth Sleepiness Scale for Children and Adolescents, FIS = Fatigue Impact Scale, FSS = Fatigue Severity Scale, FOSQ = Functional Outcomes of Sleep Questionnaire, MAF = Multidimensional Assessment of Fatigue, MSLT = Multiple Sleep Latency Test, MWT = Maintenance of Wakefulness Test, PGI = Patient Global Impression of change, PedsQL = Pediatric Quality of Life Inventory, PHQ-2 = Patient Health Questionnaire-2, PHQ-9 = Patient Health Questionnaire-9, PSG = polysomnography, PSQI- Pittsburgh Sleep Quality Index, SF-12 = 12-Item Short-Form Health Survey, SF-36 = 36-Item Short-Form Health Survey, SSS = Stanford Sleepiness Scale.