Trial Outcomes & Findings for Light Therapy for PD - Dose Selection (NCT NCT04291014)

Last Updated: 2026-03-05

Results Overview

The PDSS-2 (Parkinson's Disease Sleep Scale 2) has a total score range from 0 to 60 points. Each item on the scale is scored on a scale of 0 to 4, with higher scores indicating more severe sleep problems. The PDSS-2 is a 15-question instrument designed to simultaneously capture the multidimensional aspects of sleep-related problems and changes in sleep quality.

Recruitment status

COMPLETED

Study phase

Target enrollment

203 participants

Primary outcome timeframe

8 weeks

Results posted on

2026-03-05

Participant Flow

Participant milestones

Participant milestones
Measure	BWLT Once Daily Participants in this arm will receive bright white light therapy daily once a day (in the evening) SunRay Light Boxes: SunRay light boxes will be used to administer the light therapy.	BWLT Twice Daily Participants in this arm will receive bright white light therapy daily twice a day (morning and evening). SunRay Light Boxes: SunRay light boxes will be used to administer the light therapy.	BWLT Weekly Participants in this arm will receive bright white light therapy once weekly (in the evening). SunRay Light Boxes: SunRay light boxes will be used to administer the light therapy.	DRLT Twice Daily Participants in this arm will receive dim red light twice daily (morning and evening). SunRay Light Boxes: SunRay light boxes will be used to administer the light therapy.
Overall Study STARTED	37	39	37	37
Overall Study COMPLETED	36	33	35	32
Overall Study NOT COMPLETED	1	6	2	5

Reasons for withdrawal

Reasons for withdrawal
Measure	BWLT Once Daily Participants in this arm will receive bright white light therapy daily once a day (in the evening) SunRay Light Boxes: SunRay light boxes will be used to administer the light therapy.	BWLT Twice Daily Participants in this arm will receive bright white light therapy daily twice a day (morning and evening). SunRay Light Boxes: SunRay light boxes will be used to administer the light therapy.	BWLT Weekly Participants in this arm will receive bright white light therapy once weekly (in the evening). SunRay Light Boxes: SunRay light boxes will be used to administer the light therapy.	DRLT Twice Daily Participants in this arm will receive dim red light twice daily (morning and evening). SunRay Light Boxes: SunRay light boxes will be used to administer the light therapy.
Overall Study Withdrawal by Subject	1	6	2	5

Baseline Characteristics

Light Therapy for PD - Dose Selection

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	BWLT Once Daily n=37 Participants Participants in this arm will receive bright white light therapy daily once a day (in the evening) SunRay Light Boxes: SunRay light boxes will be used to administer the light therapy.	BWLT Twice Daily n=39 Participants Participants in this arm will receive bright white light therapy daily twice a day (morning and evening). SunRay Light Boxes: SunRay light boxes will be used to administer the light therapy.	BWLT Weekly n=37 Participants Participants in this arm will receive bright white light therapy once weekly (in the evening). SunRay Light Boxes: SunRay light boxes will be used to administer the light therapy.	DRLT Twice Daily n=37 Participants Participants in this arm will receive dim red light twice daily (morning and evening). SunRay Light Boxes: SunRay light boxes will be used to administer the light therapy.	Total n=150 Participants Total of all reporting groups
Age, Categorical <=18 years	0 Participants n=41 Participants	0 Participants n=35 Participants	0 Participants n=76 Participants	0 Participants n=565 Participants	0 Participants n=196 Participants
Age, Categorical Between 18 and 65 years	11 Participants n=41 Participants	20 Participants n=35 Participants	14 Participants n=76 Participants	14 Participants n=565 Participants	59 Participants n=196 Participants
Age, Categorical >=65 years	26 Participants n=41 Participants	19 Participants n=35 Participants	23 Participants n=76 Participants	23 Participants n=565 Participants	91 Participants n=196 Participants
Age, Continuous	67 years STANDARD_DEVIATION 8.1 • n=41 Participants	66 years STANDARD_DEVIATION 9.1 • n=35 Participants	68 years STANDARD_DEVIATION 9.2 • n=76 Participants	68 years STANDARD_DEVIATION 8.2 • n=565 Participants	67 years STANDARD_DEVIATION 8.6 • n=196 Participants
Sex: Female, Male Female	12 Participants n=41 Participants	13 Participants n=35 Participants	21 Participants n=76 Participants	11 Participants n=565 Participants	57 Participants n=196 Participants
Sex: Female, Male Male	25 Participants n=41 Participants	26 Participants n=35 Participants	16 Participants n=76 Participants	26 Participants n=565 Participants	93 Participants n=196 Participants
Race (NIH/OMB) American Indian or Alaska Native	0 Participants n=41 Participants	0 Participants n=35 Participants	0 Participants n=76 Participants	0 Participants n=565 Participants	0 Participants n=196 Participants
Race (NIH/OMB) Asian	3 Participants n=41 Participants	1 Participants n=35 Participants	1 Participants n=76 Participants	2 Participants n=565 Participants	7 Participants n=196 Participants
Race (NIH/OMB) Native Hawaiian or Other Pacific Islander	0 Participants n=41 Participants	0 Participants n=35 Participants	0 Participants n=76 Participants	0 Participants n=565 Participants	0 Participants n=196 Participants
Race (NIH/OMB) Black or African American	3 Participants n=41 Participants	2 Participants n=35 Participants	0 Participants n=76 Participants	0 Participants n=565 Participants	5 Participants n=196 Participants
Race (NIH/OMB) White	30 Participants n=41 Participants	34 Participants n=35 Participants	34 Participants n=76 Participants	35 Participants n=565 Participants	133 Participants n=196 Participants
Race (NIH/OMB) More than one race	0 Participants n=41 Participants	1 Participants n=35 Participants	1 Participants n=76 Participants	0 Participants n=565 Participants	2 Participants n=196 Participants
Race (NIH/OMB) Unknown or Not Reported	1 Participants n=41 Participants	1 Participants n=35 Participants	1 Participants n=76 Participants	0 Participants n=565 Participants	3 Participants n=196 Participants
Region of Enrollment United States	37 participants n=41 Participants	39 participants n=35 Participants	37 participants n=76 Participants	37 participants n=565 Participants	150 participants n=196 Participants

PRIMARY outcome

Timeframe: 8 weeks

Outcome measures

Outcome measures
Measure	BWLT Once Daily n=37 Participants Participants in this arm will receive bright white light therapy daily once a day (in the evening) SunRay Light Boxes: SunRay light boxes will be used to administer the light therapy.	BWLT Twice Daily n=39 Participants Participants in this arm will receive bright white light therapy daily twice a day (morning and evening). SunRay Light Boxes: SunRay light boxes will be used to administer the light therapy.	BWLT Weekly n=37 Participants Participants in this arm will receive bright white light therapy once weekly (in the evening). SunRay Light Boxes: SunRay light boxes will be used to administer the light therapy.	DRLT Twice Daily n=37 Participants Participants in this arm will receive dim red light twice daily (morning and evening). SunRay Light Boxes: SunRay light boxes will be used to administer the light therapy.
Parkinson's Disease Sleep Scale 2	-1.5202 score on a scale Interval -3.3051 to 0.2647	-2.5692 score on a scale Interval -4.4186 to -0.7198	-0.408 score on a scale Interval -2.2014 to 1.3853	-1.7608 score on a scale Interval -3.615 to 0.09342

SECONDARY outcome

Timeframe: 8 weeks

The Parkinson's Fatigue Scale (PFS-16) is a 16-item patient-rated scale that measures the presence of fatigue and its impact on daily function in patients with Parkinson's Disease. The scale includes seven items assessing the presence of fatigue and nine items measuring its impact on daily activities. The scoring range for the PFS-16 is from 1 to 5 (range 16-80), with higher scores indicating more severe fatigue. The scale is designed to exclude cognitive and emotional features of fatigue and is used to assess levels of fatigue and measure changes in response to treatment or lifestyle changes.

Outcome measures

Outcome measures
Measure	BWLT Once Daily n=37 Participants Participants in this arm will receive bright white light therapy daily once a day (in the evening) SunRay Light Boxes: SunRay light boxes will be used to administer the light therapy.	BWLT Twice Daily n=39 Participants Participants in this arm will receive bright white light therapy daily twice a day (morning and evening). SunRay Light Boxes: SunRay light boxes will be used to administer the light therapy.	BWLT Weekly n=37 Participants Participants in this arm will receive bright white light therapy once weekly (in the evening). SunRay Light Boxes: SunRay light boxes will be used to administer the light therapy.	DRLT Twice Daily n=37 Participants Participants in this arm will receive dim red light twice daily (morning and evening). SunRay Light Boxes: SunRay light boxes will be used to administer the light therapy.
Parkinson's Fatigue Scale 16	-2.1985 units on a scale Interval -5.5293 to 1.1322	-6.3956 units on a scale Interval -9.8407 to -2.9505	-0.519 units on a scale Interval -3.8617 to 2.8237	-3.8426 units on a scale Interval -7.2955 to -0.3897

SECONDARY outcome

Timeframe: 8 weeks

Outcome measures

Outcome measures
Measure	BWLT Once Daily n=37 Participants Participants in this arm will receive bright white light therapy daily once a day (in the evening) SunRay Light Boxes: SunRay light boxes will be used to administer the light therapy.	BWLT Twice Daily n=39 Participants Participants in this arm will receive bright white light therapy daily twice a day (morning and evening). SunRay Light Boxes: SunRay light boxes will be used to administer the light therapy.	BWLT Weekly n=37 Participants Participants in this arm will receive bright white light therapy once weekly (in the evening). SunRay Light Boxes: SunRay light boxes will be used to administer the light therapy.	DRLT Twice Daily n=37 Participants Participants in this arm will receive dim red light twice daily (morning and evening). SunRay Light Boxes: SunRay light boxes will be used to administer the light therapy.
Parkinson's Disease Sleep Scale 2	-1.5202 units on a scale Interval -3.3051 to 0.2647	-2.5692 units on a scale Interval -4.4186 to -0.7198	-0.408 units on a scale Interval -2.2014 to 1.3853	-1.7608 units on a scale Interval -3.615 to 0.09342

SECONDARY outcome

Timeframe: 8 weeks

Population: While LT logs were collected for all treatment arms, the secondary analysis for adherence using the GLMM was pre-specified to only compare the two active treatment groups of once and twice-daily BWLT. This was done to provide more information on the treatment group that would be potentially selected to carry forward in a phase III efficacy trial.

The secondary objective of adherence centered on frequency of use. Participants recorded light exposure duration and timing daily using a LT log. For each prescribed active treatment dose frequency (once-daily BWLT, twice-daily BWLT), a binary measure of adherence was recorded for each expected day based on whether or not they completed LT at the correct frequency. The overall percentage of those days where participants completed LT at the correct frequency were compared between the two daily BWLT treatments using a generalized linear mixed model.

Outcome measures

Outcome measures
Measure	BWLT Once Daily n=37 Participants Participants in this arm will receive bright white light therapy daily once a day (in the evening) SunRay Light Boxes: SunRay light boxes will be used to administer the light therapy.	BWLT Twice Daily n=39 Participants Participants in this arm will receive bright white light therapy daily twice a day (morning and evening). SunRay Light Boxes: SunRay light boxes will be used to administer the light therapy.	BWLT Weekly Participants in this arm will receive bright white light therapy once weekly (in the evening). SunRay Light Boxes: SunRay light boxes will be used to administer the light therapy.	DRLT Twice Daily Participants in this arm will receive dim red light twice daily (morning and evening). SunRay Light Boxes: SunRay light boxes will be used to administer the light therapy.
Adherence	83.39 percentage of adherence Interval 74.05 to 89.84	67.55 percentage of adherence Interval 54.69 to 78.21	—	—

Adverse Events

BWLT Once Daily

Serious events: 1 serious events

Other events: 5 other events

Deaths: 0 deaths

BWLT Twice Daily

Serious events: 0 serious events

Other events: 7 other events

Deaths: 0 deaths

BWLT Weekly

Serious events: 1 serious events

Other events: 4 other events

Deaths: 0 deaths

DRLT Twice Daily

Serious events: 3 serious events

Other events: 5 other events

Deaths: 0 deaths

Serious adverse events

Serious adverse events
Measure	BWLT Once Daily n=37 participants at risk Participants in this arm will receive bright white light therapy daily once a day (in the evening) SunRay Light Boxes: SunRay light boxes will be used to administer the light therapy.	BWLT Twice Daily n=39 participants at risk Participants in this arm will receive bright white light therapy daily twice a day (morning and evening). SunRay Light Boxes: SunRay light boxes will be used to administer the light therapy.	BWLT Weekly n=37 participants at risk Participants in this arm will receive bright white light therapy once weekly (in the evening). SunRay Light Boxes: SunRay light boxes will be used to administer the light therapy.	DRLT Twice Daily n=37 participants at risk Participants in this arm will receive dim red light twice daily (morning and evening). SunRay Light Boxes: SunRay light boxes will be used to administer the light therapy.
General disorders Syncope	0.00% 0/37 • Participants were monitored for AEs from the time they provide informed consent until 30 days following their completion of the study (including early termination), on average for 4 months. At that point, all ongoing AEs were followed to resolution.	0.00% 0/39 • Participants were monitored for AEs from the time they provide informed consent until 30 days following their completion of the study (including early termination), on average for 4 months. At that point, all ongoing AEs were followed to resolution.	0.00% 0/37 • Participants were monitored for AEs from the time they provide informed consent until 30 days following their completion of the study (including early termination), on average for 4 months. At that point, all ongoing AEs were followed to resolution.	2.7% 1/37 • Number of events 1 • Participants were monitored for AEs from the time they provide informed consent until 30 days following their completion of the study (including early termination), on average for 4 months. At that point, all ongoing AEs were followed to resolution.
General disorders Dehydration	0.00% 0/37 • Participants were monitored for AEs from the time they provide informed consent until 30 days following their completion of the study (including early termination), on average for 4 months. At that point, all ongoing AEs were followed to resolution.	0.00% 0/39 • Participants were monitored for AEs from the time they provide informed consent until 30 days following their completion of the study (including early termination), on average for 4 months. At that point, all ongoing AEs were followed to resolution.	0.00% 0/37 • Participants were monitored for AEs from the time they provide informed consent until 30 days following their completion of the study (including early termination), on average for 4 months. At that point, all ongoing AEs were followed to resolution.	2.7% 1/37 • Number of events 1 • Participants were monitored for AEs from the time they provide informed consent until 30 days following their completion of the study (including early termination), on average for 4 months. At that point, all ongoing AEs were followed to resolution.
Surgical and medical procedures Neck surgery	2.7% 1/37 • Number of events 1 • Participants were monitored for AEs from the time they provide informed consent until 30 days following their completion of the study (including early termination), on average for 4 months. At that point, all ongoing AEs were followed to resolution.	0.00% 0/39 • Participants were monitored for AEs from the time they provide informed consent until 30 days following their completion of the study (including early termination), on average for 4 months. At that point, all ongoing AEs were followed to resolution.	0.00% 0/37 • Participants were monitored for AEs from the time they provide informed consent until 30 days following their completion of the study (including early termination), on average for 4 months. At that point, all ongoing AEs were followed to resolution.	0.00% 0/37 • Participants were monitored for AEs from the time they provide informed consent until 30 days following their completion of the study (including early termination), on average for 4 months. At that point, all ongoing AEs were followed to resolution.
Skin and subcutaneous tissue disorders Basal cell carcinoma	0.00% 0/37 • Participants were monitored for AEs from the time they provide informed consent until 30 days following their completion of the study (including early termination), on average for 4 months. At that point, all ongoing AEs were followed to resolution.	0.00% 0/39 • Participants were monitored for AEs from the time they provide informed consent until 30 days following their completion of the study (including early termination), on average for 4 months. At that point, all ongoing AEs were followed to resolution.	0.00% 0/37 • Participants were monitored for AEs from the time they provide informed consent until 30 days following their completion of the study (including early termination), on average for 4 months. At that point, all ongoing AEs were followed to resolution.	2.7% 1/37 • Number of events 1 • Participants were monitored for AEs from the time they provide informed consent until 30 days following their completion of the study (including early termination), on average for 4 months. At that point, all ongoing AEs were followed to resolution.
Renal and urinary disorders Urinary tract infection	0.00% 0/37 • Participants were monitored for AEs from the time they provide informed consent until 30 days following their completion of the study (including early termination), on average for 4 months. At that point, all ongoing AEs were followed to resolution.	0.00% 0/39 • Participants were monitored for AEs from the time they provide informed consent until 30 days following their completion of the study (including early termination), on average for 4 months. At that point, all ongoing AEs were followed to resolution.	2.7% 1/37 • Number of events 1 • Participants were monitored for AEs from the time they provide informed consent until 30 days following their completion of the study (including early termination), on average for 4 months. At that point, all ongoing AEs were followed to resolution.	0.00% 0/37 • Participants were monitored for AEs from the time they provide informed consent until 30 days following their completion of the study (including early termination), on average for 4 months. At that point, all ongoing AEs were followed to resolution.

Other adverse events

Other adverse events
Measure	BWLT Once Daily n=37 participants at risk Participants in this arm will receive bright white light therapy daily once a day (in the evening) SunRay Light Boxes: SunRay light boxes will be used to administer the light therapy.	BWLT Twice Daily n=39 participants at risk Participants in this arm will receive bright white light therapy daily twice a day (morning and evening). SunRay Light Boxes: SunRay light boxes will be used to administer the light therapy.	BWLT Weekly n=37 participants at risk Participants in this arm will receive bright white light therapy once weekly (in the evening). SunRay Light Boxes: SunRay light boxes will be used to administer the light therapy.	DRLT Twice Daily n=37 participants at risk Participants in this arm will receive dim red light twice daily (morning and evening). SunRay Light Boxes: SunRay light boxes will be used to administer the light therapy.
Musculoskeletal and connective tissue disorders Back pain	5.4% 2/37 • Number of events 2 • Participants were monitored for AEs from the time they provide informed consent until 30 days following their completion of the study (including early termination), on average for 4 months. At that point, all ongoing AEs were followed to resolution.	0.00% 0/39 • Participants were monitored for AEs from the time they provide informed consent until 30 days following their completion of the study (including early termination), on average for 4 months. At that point, all ongoing AEs were followed to resolution.	0.00% 0/37 • Participants were monitored for AEs from the time they provide informed consent until 30 days following their completion of the study (including early termination), on average for 4 months. At that point, all ongoing AEs were followed to resolution.	0.00% 0/37 • Participants were monitored for AEs from the time they provide informed consent until 30 days following their completion of the study (including early termination), on average for 4 months. At that point, all ongoing AEs were followed to resolution.
Musculoskeletal and connective tissue disorders Musculoskeletal pain	5.4% 2/37 • Number of events 2 • Participants were monitored for AEs from the time they provide informed consent until 30 days following their completion of the study (including early termination), on average for 4 months. At that point, all ongoing AEs were followed to resolution.	2.6% 1/39 • Number of events 1 • Participants were monitored for AEs from the time they provide informed consent until 30 days following their completion of the study (including early termination), on average for 4 months. At that point, all ongoing AEs were followed to resolution.	0.00% 0/37 • Participants were monitored for AEs from the time they provide informed consent until 30 days following their completion of the study (including early termination), on average for 4 months. At that point, all ongoing AEs were followed to resolution.	0.00% 0/37 • Participants were monitored for AEs from the time they provide informed consent until 30 days following their completion of the study (including early termination), on average for 4 months. At that point, all ongoing AEs were followed to resolution.
General disorders Influenza like Illness	0.00% 0/37 • Participants were monitored for AEs from the time they provide informed consent until 30 days following their completion of the study (including early termination), on average for 4 months. At that point, all ongoing AEs were followed to resolution.	0.00% 0/39 • Participants were monitored for AEs from the time they provide informed consent until 30 days following their completion of the study (including early termination), on average for 4 months. At that point, all ongoing AEs were followed to resolution.	5.4% 2/37 • Number of events 2 • Participants were monitored for AEs from the time they provide informed consent until 30 days following their completion of the study (including early termination), on average for 4 months. At that point, all ongoing AEs were followed to resolution.	2.7% 1/37 • Number of events 1 • Participants were monitored for AEs from the time they provide informed consent until 30 days following their completion of the study (including early termination), on average for 4 months. At that point, all ongoing AEs were followed to resolution.
Infections and infestations Upper respiratory tract infection	0.00% 0/37 • Participants were monitored for AEs from the time they provide informed consent until 30 days following their completion of the study (including early termination), on average for 4 months. At that point, all ongoing AEs were followed to resolution.	2.6% 1/39 • Number of events 1 • Participants were monitored for AEs from the time they provide informed consent until 30 days following their completion of the study (including early termination), on average for 4 months. At that point, all ongoing AEs were followed to resolution.	5.4% 2/37 • Number of events 2 • Participants were monitored for AEs from the time they provide informed consent until 30 days following their completion of the study (including early termination), on average for 4 months. At that point, all ongoing AEs were followed to resolution.	5.4% 2/37 • Number of events 2 • Participants were monitored for AEs from the time they provide informed consent until 30 days following their completion of the study (including early termination), on average for 4 months. At that point, all ongoing AEs were followed to resolution.
Musculoskeletal and connective tissue disorders neck pain	0.00% 0/37 • Participants were monitored for AEs from the time they provide informed consent until 30 days following their completion of the study (including early termination), on average for 4 months. At that point, all ongoing AEs were followed to resolution.	5.1% 2/39 • Number of events 2 • Participants were monitored for AEs from the time they provide informed consent until 30 days following their completion of the study (including early termination), on average for 4 months. At that point, all ongoing AEs were followed to resolution.	0.00% 0/37 • Participants were monitored for AEs from the time they provide informed consent until 30 days following their completion of the study (including early termination), on average for 4 months. At that point, all ongoing AEs were followed to resolution.	0.00% 0/37 • Participants were monitored for AEs from the time they provide informed consent until 30 days following their completion of the study (including early termination), on average for 4 months. At that point, all ongoing AEs were followed to resolution.
Nervous system disorders Headache	2.7% 1/37 • Number of events 1 • Participants were monitored for AEs from the time they provide informed consent until 30 days following their completion of the study (including early termination), on average for 4 months. At that point, all ongoing AEs were followed to resolution.	7.7% 3/39 • Number of events 3 • Participants were monitored for AEs from the time they provide informed consent until 30 days following their completion of the study (including early termination), on average for 4 months. At that point, all ongoing AEs were followed to resolution.	0.00% 0/37 • Participants were monitored for AEs from the time they provide informed consent until 30 days following their completion of the study (including early termination), on average for 4 months. At that point, all ongoing AEs were followed to resolution.	5.4% 2/37 • Number of events 2 • Participants were monitored for AEs from the time they provide informed consent until 30 days following their completion of the study (including early termination), on average for 4 months. At that point, all ongoing AEs were followed to resolution.

Additional Information

Aleksandar Videnovic, MD, Associate Professor of Neurology

Massachusetts General Hospital

Phone: 617-724-3837

Email: [email protected]

Results disclosure agreements

Principal investigator is a sponsor employee
Publication restrictions are in place