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Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Date data sharing statement initially provided
Type of registration
Prospectively registered

Titles & IDs
Public title
Photoreceptor-directed light therapy in Parkinson’s disease
Scientific title
Effect of photoreceptor-directed light therapy on sleep in Parkinson's disease
Secondary ID [1] 302676 0
Nil Known
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Parkinson's disease 319595 0
Circadian disruption 319915 0
Sleep disruption 319916 0
Condition category
Condition code
Neurological 317533 317533 0 0
Parkinson's disease

Study type
Description of intervention(s) / exposure
Supplemental light therapy:
Arm 1: High melanopsin light
Arm 2: Low melanopsin light

The ‘high’ melanopsin state has a relatively increased spectral component around the peak sensitivity of the melanopsin photopigment. The ‘low’ melanopsin state has a relatively reduced spectral component in that range compared with the ‘high’ state.
The melanopsin contrast between these states is approximately 25%. Each state’s total radiometric power is approximately 1.4W/m^2 (watts per square metre) and 2.8W/m^2 respectively, measured at 30cm. Of this, 0.445W/m^2 and 0.56W/m^2 respectively is acting on melanopsin photoreceptors, and both states have 0.808W/m^2 attributable to photometric luminance. Both states will not deliver more than the industry standard 10,000 lux at a 16cm viewing distance (e.g. approximately 5,000 lux).

The participant will view the light for 30 minutes daily at home for 4 weeks. The participant will be instructed face to face by one of the research team members on the use of the light.

We personalize the timing (morning or evening) of the daily (30min) light exposure based on a person’s chronotype to control for individual differences in activity and alertness in the morning and evening. Chronotypes will be determined with the Morningness Eveningness questionnaire.

Actigraphy data provide an additional control measure to ensure adherence to the light intervention methodologies; that is, if the participant incorrectly uses the light, the actigraphy data will return lower light exposure when light box should have been used.
Intervention code [1] 318959 0
Treatment: Devices
Comparator / control treatment
The comparator/control arm is the low melanopsin light.
Control group
Dose comparison

Primary outcome [1] 325567 0
Polysomnography (PSG) sleep latency > 8 min difference
Timepoint [1] 325567 0
Participants will be assessed at baseline (day 1-3) before light intervention, 4 weeks (primary timepoint) and 6 weeks post-commencement of light intervention.
Primary outcome [2] 325569 0
Polysomnography (PSG) sleep efficiency > 7 min difference
Timepoint [2] 325569 0
baseline (day 1-3 before light intervention), 4 weeks (primary timepoint) and 6 weeks after light intervention
Primary outcome [3] 325570 0
Dim Light Melatonin Onset determined from salivary samples > 65 min difference
Timepoint [3] 325570 0
baseline (day 1-3 before light intervention), 4 weeks (primary timepoint) and 6 weeks after light intervention
Secondary outcome [1] 388406 0
Pittsburgh Sleep Quality Index > 1.6 difference
Timepoint [1] 388406 0
baseline (day 1-3 before light intervention), 4 weeks and 6 weeks after light intervention
Secondary outcome [2] 388407 0
Epworth Sleepiness Scale > 4.6 difference
Timepoint [2] 388407 0
baseline (day 1-3 before light intervention), 4 weeks and 6 weeks after light intervention
Secondary outcome [3] 388408 0
Motor function: Gait: step velocity > 0.14 m/s difference
Timed walk test on pressure sensitive Mat
Timepoint [3] 388408 0
baseline (day 1-3 before light intervention), 4 weeks and 6 weeks after light intervention
Secondary outcome [4] 388409 0
Motor function: Tremor (postural) > 4 Hz difference
Resting tremor with accelerometer on left and right fingers
Timepoint [4] 388409 0
baseline (day 1-3 before light intervention), 4 weeks and 6 weeks after light intervention

Key inclusion criteria
• People with PD based on the unified Parkinson’s Disease Rating Scale (MDS-UPDRS) and Hoehn & Yahr staging (I-IV).
• Healthy eyes with no anterior eye disease (i.e. lens opacities < grade 2 based on LOCS III) and no signs of retinal or optic nerve disease (diabetic retinopathy, glaucoma or age-related macular degeneration) based on ophthalmic examination (determined by an ophthalmologist, PI Feigl)
• Living independently in the community and able to walk unaided

Minimum age
18 Years
Maximum age
No limit
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
• Inability to comply with study follow up
• Participants having travelled across 2 or more time zones within 90 days before start of the study
• Dementia based on MMSE (<24) and ACE (<82) assessments
• Deep brain stimulation, other device assisted therapies (i.e. red light therapy) or CNS surgery
• Any type of systemic disease or any medical condition (controlled or uncontrolled) other than PD that could be expected to significantly affect the health of a participant
• A periodic limb movement disorder index (PLMI) > 15/hour in PSG
• Significant sleep apnea (AHI apnoea-hypnoea index > 15 events/hour) and loss of REM atonia in PSG
• Recent or recurrent history of musculoskeletal injury or surgery

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Central randomisation by computer
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Simple randomisation using a randomisation table created by computer software (i.e. computerized sequence generation)
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?
The people receiving the treatment/s
The people administering the treatment/s
The people assessing the outcomes
The people analysing the results/data
Intervention assignment
Other design features
Not Applicable
Type of endpoint(s)
Statistical methods / analysis
Power and Sample size calculation are based on established formulae. Mean difference data (effect size) are based on published studies in PD.

All statistical analyses will be performed using SPSS (IBM SPSS, version 23; IBM Corporation, Armonk, NY, USA) and GraphPad Prism (GraphPad Software, Inc., CA, USA). The data will be screened for normality using the Shapiro-Wilk test. Means of the parametric data between the groups before and after light intervention will be compared using ANOVA and non-parametric data using Kruskal Wallis (Dunn’s multiple comparisons) analysis of variance to determine a group difference with p<0.05. Subsequent post-hoc comparison between groups will be assessed using Mann Whitney U test and Bonferroni corrections for multiple comparisons. Pearson or Spearman’s rank correlation coefficients will be calculated to assess bivariate associations. We use linear and logistic regression models to control for covariates (age, gender).

Recruitment status
Not yet recruiting
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment in Australia
Recruitment state(s)
Recruitment postcode(s) [1] 31810 0
4059 - Kelvin Grove

Funding & Sponsors
Funding source category [1] 307115 0
Name [1] 307115 0
Michael J Fox Foundation for Parkinson's Research
Address [1] 307115 0
Grand Central Station. P.O. Box 4777. New York, NY 10163-4777
Country [1] 307115 0
United States of America
Funding source category [2] 307116 0
Name [2] 307116 0
Shake IT Up Australia Foundation
Address [2] 307116 0
PO Box 710, Spit Junction NSW 2088
Country [2] 307116 0
Primary sponsor type
Queensland University of Technology
2 George St., Brisbane Queensland 4001
Secondary sponsor category [1] 307685 0
Name [1] 307685 0
Address [1] 307685 0
Country [1] 307685 0

Ethics approval
Ethics application status
Ethics committee name [1] 307228 0
QUT Office of Research and ethics Integrety (OREI)
Ethics committee address [1] 307228 0
GPO Box 2434 QLD 4000
Ethics committee country [1] 307228 0
Date submitted for ethics approval [1] 307228 0
Approval date [1] 307228 0
Ethics approval number [1] 307228 0

Brief summary
In this project, we will use a new therapeutic lighting technology developed by our team at Queensland University of Technology, that can provide preferentially directed light spectrums to increase melanopsin activity thus may improve non-motor circadian/sleep behavior and motor symptoms in people with PD.
Participants will be exposed to the light therapy at home every day for 30 minutes over 4 weeks and sleep and motor function will be assessed before, after 4 and 6 weeks of light intervention.

We hypothesize that using light to preferentially activate melanopsin cells in the eye will help people with Parkinson’s disease sleep better. A better sleep will also positively impact on their movements such as balance, gait and tremor during the day.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 106478 0
A/Prof Beatrix Feigl
Address 106478 0
Queensland University of Technology
60 Musk Avenue, Kelvin Grove 4059
Country 106478 0
Phone 106478 0
+61 07 31 38 6147
Fax 106478 0
Email 106478 0
Contact person for public queries
Name 106479 0
A/Prof Beatrix Feigl
Address 106479 0
Queensland University of Technology
60 Musk Avenue, Kelvin Grove 4059
Country 106479 0
Phone 106479 0
+61 07 31 38 6147
Fax 106479 0
Email 106479 0
Contact person for scientific queries
Name 106480 0
A/Prof Beatrix Feigl
Address 106480 0
Queensland University of Technology
60 Musk Avenue, Kelvin Grove 4059
Country 106480 0
Phone 106480 0
+61 07 31 38 6147
Fax 106480 0
Email 106480 0

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No/undecided IPD sharing reason/comment
Individual data will not be shared in line with participants confidentiality and according to ethical approval.
What supporting documents are/will be available?
No other documents available
Summary results
No Results