Table 3.

Summary of clinical significance thresholds for critical and important outcome measures.

Outcome Tool	Clinical Significance Threshold*	Expected Change
Frequency of significant bed partner sleep disruption
CGI-I	1.5 points OR 65% of patients reporting change	Decrease Improvement
Frequency and/or intensity of dream enactment episodes
Simple motor behaviors (PSG—during REM sleep)	33% (10% for placebo studies) OR 50% of patients reporting change	Decrease Improvement
Complex motor behaviors (PSG—during REM sleep)	33% (10% for placebo studies) OR 50% of patients reporting change	Decrease Improvement
CGI-I	1.5 points OR 65% of patients reporting change	Decrease Improvement
RBDQ (Factor 2 score)	10% OR 50% of patients reporting change	Decrease Improvement
Treatment-related worsening in sedation or cognitive impairment
ESS	2 points OR 10% of patients reporting change	Increase Decline
KESS	2 points OR 10% of patients reporting change	Increase Decline
MMSE	3 points OR 10% of patients reporting change	Decrease Decline
Letter Fluency	10% OR 33% of patients reporting change	Decrease Decline
MFQ	1 point OR 10% of patients reporting change	Increase Decline
Treatment-related worsening in gait stability	10% of patients reporting change	Decline
Treatment-related worsening in symptoms of depression or anxiety
NPI	4 points OR 20% of patients reporting change	Increase Decline
Frequency and/or intensity of unpleasant dreams and nightmares
RBD frequency	33% (10% for placebo studies) OR 50% of patients reporting change	Decrease Improvement
RBD intensity	33% (10% for placebo studies) OR 50% of patients reporting change	Decrease Improvement
RBD episodes per week or month	33% (10% for placebo studies) OR 50% of patients reporting change	Decrease Improvement
RBDQ (Factor 1 score)	10% OR 50% of patients reporting change	Decrease Improvement
Change in REM motor tone—tonic and/or phasic
Phasic EMG%	10% OR 50% of patients with change in REM motor tone	Decrease Improvement
Tonic EMG%	10% OR 50% of patients with change in REM motor tone	Decrease Improvement
REM Atonia Index	10% OR 50% of patients with change in REM motor tone	Increase Improvement
Quality of life
SF-36 (physical score)	10% OR 50% of patients reporting change	Increase Improvement
SF-36 (mental score)	10% OR 40% of patients reporting change	Increase Improvement
UPDRS (total score)	4.1 points OR 50% of patients reporting change	Decrease Improvement
Schwab and England	20% OR 60% of patients reporting change	Increase Improvement
CGI-I	1.5 points OR 50% of patients reporting change	Decrease Improvement
Sleep quality
RBDQ (total score)	10% OR 50% of patients reporting change	Decrease Improvement
PSQI	3 points OR 50% of patients reporting change	Decrease Improvement
Daytime motor function
UPDRS (Part III score)	2.3 points OR 50% of patients reporting change	Decrease Improvement

^*The clinical significance thresholds apply to the comparison of post-treatment effects between intervention and placebo as well as a pre-post treatment difference. CGI-I = Clinical Global Impressions–Improvement Scale, EMG = electromyography, ESS = Epworth Sleepiness Scale, KESS = Korean Epworth Sleepiness Scale, MFQ = Mayo Fluctuation Questionnaire, MMSE = Mini-Mental State Examination, NPI = Neuro-psychiatric Inventory, PSQI = Pittsburgh Sleep Quality Index, RBD = rapid eye movement sleep behavior disorder, RBDQ = RBD Questionnaire (includes Korean, Japanese, and Hong Kong versions), REM = rapid eye movement, RWA = REM sleep without atonia, SF-36 = Short-Form Questionnaire (36-item), UPDRS = Unified Parkinson’s Disease Rating Scale.